Removed some old unused code, found by Moez Mahfoudh

[thirdparty/squid.git] / src / client_side.cc

/*
 * $Id: client_side.cc,v 1.518 2000/12/17 07:18:56 hno Exp $
 *
 * DEBUG: section 33    Client-side Routines
 * AUTHOR: Duane Wessels
 *
 * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from the
 *  Internet community.  Development is led by Duane Wessels of the
 *  National Laboratory for Applied Network Research and funded by the
 *  National Science Foundation.  Squid is Copyrighted (C) 1998 by
 *  the Regents of the University of California.  Please see the
 *  COPYRIGHT file for full details.  Squid incorporates software
 *  developed and/or copyrighted by other sources.  Please see the
 *  CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"

#if IPF_TRANSPARENT
#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#include <netinet/tcp.h>
#include <net/if.h>
#if HAVE_IP_FIL_COMPAT_H
#include <ip_fil_compat.h>
#elif HAVE_NETINET_IP_FIL_COMPAT_H
#include <netinet/ip_fil_compat.h>
#elif HAVE_IP_COMPAT_H
#include <ip_compat.h>
#elif HAVE_NETINET_IP_COMPAT_H
#include <netinet/ip_compat.h>
#endif
#if HAVE_IP_FIL_H
#include <ip_fil.h>
#elif HAVE_NETINET_IP_FIL_H
#include <netinet/ip_fil.h>
#endif
#if HAVE_IP_NAT_H
#include <ip_nat.h>
#elif HAVE_NETINET_IP_NAT_H
#include <netinet/ip_nat.h>
#endif
#endif

#if LINUX_NETFILTER
#include <linux/netfilter_ipv4.h>
#endif


#if LINGERING_CLOSE
#define comm_close comm_lingering_close
#endif

static const char *const crlf = "\r\n";

#define FAILURE_MODE_TIME 300

/* Local functions */

static CWCB clientWriteComplete;
static CWCB clientWriteBodyComplete;
static PF clientReadRequest;
static PF connStateFree;
static PF requestTimeout;
static PF clientLifetimeTimeout;
static int clientCheckTransferDone(clientHttpRequest *);
static int clientGotNotEnough(clientHttpRequest *);
static void checkFailureRatio(err_type, hier_code);
static void clientProcessMiss(clientHttpRequest *);
static void clientBuildReplyHeader(clientHttpRequest * http, HttpReply * rep);
static clientHttpRequest *parseHttpRequestAbort(ConnStateData * conn, const char *uri);
static clientHttpRequest *parseHttpRequest(ConnStateData *, method_t *, int *, char **, size_t *);
static RH clientRedirectDone;
static void clientCheckNoCache(clientHttpRequest *);
static void clientCheckNoCacheDone(int answer, void *data);
static STCB clientHandleIMSReply;
static int clientGetsOldEntry(StoreEntry * new, StoreEntry * old, request_t * request);
static int checkAccelOnly(clientHttpRequest *);
#if USE_IDENT
static IDCB clientIdentDone;
#endif
static int clientOnlyIfCached(clientHttpRequest * http);
static STCB clientSendMoreData;
static STCB clientCacheHit;
static void clientSetKeepaliveFlag(clientHttpRequest *);
static void clientPackRangeHdr(const HttpReply * rep, const HttpHdrRangeSpec * spec, String boundary, MemBuf * mb);
static void clientPackTermBound(String boundary, MemBuf * mb);
static void clientInterpretRequestHeaders(clientHttpRequest *);
static void clientProcessRequest(clientHttpRequest *);
static void clientProcessExpired(void *data);
static void clientProcessOnlyIfCachedMiss(clientHttpRequest * http);
static int clientCachable(clientHttpRequest * http);
static int clientHierarchical(clientHttpRequest * http);
static int clientCheckContentLength(request_t * r);
static DEFER httpAcceptDefer;
static log_type clientProcessRequest2(clientHttpRequest * http);
static int clientReplyBodyTooLarge(int clen);
static int clientRequestBodyTooLarge(int clen);

static int
checkAccelOnly(clientHttpRequest * http)
{
    /* return TRUE if someone makes a proxy request to us and
     * we are in httpd-accel only mode */
    if (!Config2.Accel.on)
        return 0;
    if (Config.onoff.accel_with_proxy)
        return 0;
    if (http->request->protocol == PROTO_CACHEOBJ)
        return 0;
    if (http->flags.accel)
        return 0;
    return 1;
}

#if USE_IDENT
static void
clientIdentDone(const char *ident, void *data)
{
    ConnStateData *conn = data;
    if (ident)
        xstrncpy(conn->ident, ident, sizeof(conn->ident));
    else
        xstrncpy(conn->ident, "-", sizeof(conn->ident));
}
#endif

static aclCheck_t *
clientAclChecklistCreate(const acl_access * acl, const clientHttpRequest * http)
{
    aclCheck_t *ch;
    ConnStateData *conn = http->conn;
    ch = aclChecklistCreate(acl,
        http->request,
        conn->ident);
#if USE_IDENT
    /*
     * hack for ident ACL. It needs to get full addresses, and a
     * place to store the ident result on persistent connections...
     */
    ch->conn = conn;
    cbdataLock(ch->conn);
#endif
    return ch;
}

void
clientAccessCheck(void *data)
{
    clientHttpRequest *http = data;
    if (checkAccelOnly(http)) {
        /* deny proxy requests in accel_only mode */
        debug(33, 1) ("clientAccessCheck: proxy request denied in accel_only mode\n");
        clientAccessCheckDone(ACCESS_DENIED, http);
        return;
    }
    http->acl_checklist = clientAclChecklistCreate(Config.accessList.http, http);
    aclNBCheck(http->acl_checklist, clientAccessCheckDone, http);
}

/*
 * returns true if client specified that the object must come from the cache
 * without contacting origin server
 */
static int
clientOnlyIfCached(clientHttpRequest * http)
{
    const request_t *r = http->request;
    assert(r);
    return r->cache_control &&
        EBIT_TEST(r->cache_control->mask, CC_ONLY_IF_CACHED);
}

StoreEntry *
clientCreateStoreEntry(clientHttpRequest * h, method_t m, request_flags flags)
{
    StoreEntry *e;
    /*
     * For erroneous requests, we might not have a h->request,
     * so make a fake one.
     */
    if (h->request == NULL)
        h->request = requestLink(requestCreate(m, PROTO_NONE, null_string));
    e = storeCreateEntry(h->uri, h->log_uri, flags, m);
    h->sc = storeClientListAdd(e, h);
#if DELAY_POOLS
    delaySetStoreClient(h->sc, delayClient(h->request));
#endif
    storeClientCopy(h->sc, e, 0, 0, CLIENT_SOCK_SZ,
        memAllocate(MEM_CLIENT_SOCK_BUF), clientSendMoreData, h);
    return e;
}

void
clientAccessCheckDone(int answer, void *data)
{
    clientHttpRequest *http = data;
    int page_id = -1;
    http_status status;
    ErrorState *err = NULL;
    char *proxy_auth_msg = NULL;
    debug(33, 2) ("The request %s %s is %s, because it matched '%s'\n",
        RequestMethodStr[http->request->method], http->uri,
        answer == ACCESS_ALLOWED ? "ALLOWED" : "DENIED",
        AclMatchedName ? AclMatchedName : "NO ACL's");
    if (http->acl_checklist->auth_user)
        proxy_auth_msg = http->acl_checklist->auth_user->message;
    http->acl_checklist = NULL;
    if (answer == ACCESS_ALLOWED) {
        safe_free(http->uri);
        http->uri = xstrdup(urlCanonical(http->request));
        assert(http->redirect_state == REDIRECT_NONE);
        http->redirect_state = REDIRECT_PENDING;
        redirectStart(http, clientRedirectDone, http);
    } else {
        debug(33, 5) ("Access Denied: %s\n", http->uri);
        debug(33, 5) ("AclMatchedName = %s\n",
            AclMatchedName ? AclMatchedName : "<null>");
        debug(33, 5) ("Proxy Auth Message = %s\n",
            proxy_auth_msg ? proxy_auth_msg : "<null>");
        /*
         * NOTE: get page_id here, based on AclMatchedName because
         * if USE_DELAY_POOLS is enabled, then AclMatchedName gets
         * clobbered in the clientCreateStoreEntry() call
         * just below.  Pedro Ribeiro <pribeiro@isel.pt>
         */
        page_id = aclGetDenyInfoPage(&Config.denyInfoList, AclMatchedName);
        http->log_type = LOG_TCP_DENIED;
        http->entry = clientCreateStoreEntry(http, http->request->method,
            null_request_flags);
        if (answer == ACCESS_REQ_PROXY_AUTH || aclIsProxyAuth(AclMatchedName)) {
            if (!http->flags.accel) {
                /* Proxy authorisation needed */
                status = HTTP_PROXY_AUTHENTICATION_REQUIRED;
            } else {
                /* WWW authorisation needed */
                status = HTTP_UNAUTHORIZED;
            }
            if (page_id <= 0)
                page_id = ERR_CACHE_ACCESS_DENIED;
        } else {
            status = HTTP_FORBIDDEN;
            if (page_id <= 0)
                page_id = ERR_ACCESS_DENIED;
        }
        err = errorCon(page_id, status);
        err->request = requestLink(http->request);
        err->src_addr = http->conn->peer.sin_addr;
        err->proxy_auth_msg = proxy_auth_msg;
        err->callback_data = NULL;
        errorAppendEntry(http->entry, err);
    }
}

static void
clientRedirectDone(void *data, char *result)
{
    clientHttpRequest *http = data;
    request_t *new_request = NULL;
    request_t *old_request = http->request;
    debug(33, 5) ("clientRedirectDone: '%s' result=%s\n", http->uri,
        result ? result : "NULL");
    assert(http->redirect_state == REDIRECT_PENDING);
    http->redirect_state = REDIRECT_DONE;
    if (result) {
        http_status status = atoi(result);
        if (status == 301 || status == 302) {
            char *t = result;
            if ((t = strchr(result, ':')) != NULL) {
                http->redirect.status = status;
                http->redirect.location = xstrdup(t + 1);
            } else {
                debug(33, 1) ("clientRedirectDone: bad input: %s\n", result);
            }
        }
        if (strcmp(result, http->uri))
            new_request = urlParse(old_request->method, result);
    }
    if (new_request) {
        safe_free(http->uri);
        http->uri = xstrdup(urlCanonical(new_request));
        new_request->http_ver = old_request->http_ver;
        httpHeaderAppend(&new_request->header, &old_request->header);
        new_request->client_addr = old_request->client_addr;
        new_request->my_addr = old_request->my_addr;
        new_request->my_port = old_request->my_port;
        new_request->flags.redirected = 1;
        if (old_request->user_ident[0])
            xstrncpy(new_request->user_ident, old_request->user_ident,
                USER_IDENT_SZ);
        if (old_request->body) {
            new_request->body = xmalloc(old_request->body_sz);
            xmemcpy(new_request->body, old_request->body, old_request->body_sz);
            new_request->body_sz = old_request->body_sz;
        }
        new_request->content_length = old_request->content_length;
        new_request->flags.proxy_keepalive = old_request->flags.proxy_keepalive;
        requestUnlink(old_request);
        http->request = requestLink(new_request);
    }
    clientInterpretRequestHeaders(http);
#if HEADERS_LOG
    headersLog(0, 1, request->method, request);
#endif
    fd_note(http->conn->fd, http->uri);
    clientCheckNoCache(http);
}

static void
clientCheckNoCache(clientHttpRequest * http)
{
    if (Config.accessList.noCache && http->request->flags.cachable) {
        http->acl_checklist = clientAclChecklistCreate(Config.accessList.noCache, http);
        aclNBCheck(http->acl_checklist, clientCheckNoCacheDone, http);
    } else {
        clientCheckNoCacheDone(http->request->flags.cachable, http);
    }
}

void
clientCheckNoCacheDone(int answer, void *data)
{
    clientHttpRequest *http = data;
    http->request->flags.cachable = answer;
    http->acl_checklist = NULL;
    clientProcessRequest(http);
}

static void
clientProcessExpired(void *data)
{
    clientHttpRequest *http = data;
    char *url = http->uri;
    StoreEntry *entry = NULL;
    debug(33, 3) ("clientProcessExpired: '%s'\n", http->uri);
    assert(http->entry->lastmod >= 0);
    /*
     * check if we are allowed to contact other servers
     * @?@: Instead of a 504 (Gateway Timeout) reply, we may want to return 
     *      a stale entry *if* it matches client requirements
     */
    if (clientOnlyIfCached(http)) {
        clientProcessOnlyIfCachedMiss(http);
        return;
    }
    http->request->flags.refresh = 1;
    http->old_entry = http->entry;
    http->old_sc = http->sc;
    /*
     * Assert that 'http' is already a client of old_entry.  If 
     * it is not, then the beginning of the object data might get
     * freed from memory before we need to access it.
     */
    assert(http->sc->callback_data == http);
    entry = storeCreateEntry(url,
        http->log_uri,
        http->request->flags,
        http->request->method);
    /* NOTE, don't call storeLockObject(), storeCreateEntry() does it */
    http->sc = storeClientListAdd(entry, http);
#if DELAY_POOLS
    /* delay_id is already set on original store client */
    delaySetStoreClient(http->sc, delayClient(http->request));
#endif
    http->request->lastmod = http->old_entry->lastmod;
    debug(33, 5) ("clientProcessExpired: lastmod %d\n", (int) entry->lastmod);
    http->entry = entry;
    http->out.offset = 0;
    fwdStart(http->conn->fd, http->entry, http->request);
    /* Register with storage manager to receive updates when data comes in. */
    if (EBIT_TEST(entry->flags, ENTRY_ABORTED))
        debug(33, 0) ("clientProcessExpired: found ENTRY_ABORTED object\n");
    storeClientCopy(http->sc, entry,
        http->out.offset,
        http->out.offset,
        CLIENT_SOCK_SZ,
        memAllocate(MEM_CLIENT_SOCK_BUF),
        clientHandleIMSReply,
        http);
}

static int
clientGetsOldEntry(StoreEntry * new_entry, StoreEntry * old_entry, request_t * request)
{
    const http_status status = new_entry->mem_obj->reply->sline.status;
    if (0 == status) {
        debug(33, 5) ("clientGetsOldEntry: YES, broken HTTP reply\n");
        return 1;
    }
    /* If the reply is a failure then send the old object as a last
     * resort */
    if (status >= 500 && status < 600) {
        debug(33, 3) ("clientGetsOldEntry: YES, failure reply=%d\n", status);
        return 1;
    }
    /* If the reply is anything but "Not Modified" then
     * we must forward it to the client */
    if (HTTP_NOT_MODIFIED != status) {
        debug(33, 5) ("clientGetsOldEntry: NO, reply=%d\n", status);
        return 0;
    }
    /* If the client did not send IMS in the request, then it
     * must get the old object, not this "Not Modified" reply */
    if (!request->flags.ims) {
        debug(33, 5) ("clientGetsOldEntry: YES, no client IMS\n");
        return 1;
    }
    /* If the client IMS time is prior to the entry LASTMOD time we
     * need to send the old object */
    if (modifiedSince(old_entry, request)) {
        debug(33, 5) ("clientGetsOldEntry: YES, modified since %d\n",
            (int) request->ims);
        return 1;
    }
    debug(33, 5) ("clientGetsOldEntry: NO, new one is fine\n");
    return 0;
}


static void
clientHandleIMSReply(void *data, char *buf, ssize_t size)
{
    clientHttpRequest *http = data;
    StoreEntry *entry = http->entry;
    MemObject *mem;
    const char *url = storeUrl(entry);
    int unlink_request = 0;
    StoreEntry *oldentry;
    int recopy = 1;
    http_status status;
    debug(33, 3) ("clientHandleIMSReply: %s, %d bytes\n", url, (int) size);
    if (entry == NULL) {
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    }
    if (size < 0 && !EBIT_TEST(entry->flags, ENTRY_ABORTED)) {
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    }
    mem = entry->mem_obj;
    status = mem->reply->sline.status;
    if (EBIT_TEST(entry->flags, ENTRY_ABORTED)) {
        debug(33, 3) ("clientHandleIMSReply: ABORTED '%s'\n", url);
        /* We have an existing entry, but failed to validate it */
        /* Its okay to send the old one anyway */
        http->log_type = LOG_TCP_REFRESH_FAIL_HIT;
        storeUnregister(http->sc, entry, http);
        storeUnlockObject(entry);
        entry = http->entry = http->old_entry;
        http->sc = http->old_sc;
    } else if (STORE_PENDING == entry->store_status && 0 == status) {
        debug(33, 3) ("clientHandleIMSReply: Incomplete headers for '%s'\n", url);
        if (size >= CLIENT_SOCK_SZ) {
            /* will not get any bigger than that */
            debug(33, 3) ("clientHandleIMSReply: Reply is too large '%s', using old entry\n", url);
            /* use old entry, this repeats the code abovez */
            http->log_type = LOG_TCP_REFRESH_FAIL_HIT;
            storeUnregister(http->sc, entry, http);
            storeUnlockObject(entry);
            entry = http->entry = http->old_entry;
            http->sc = http->old_sc;
            /* continue */
        } else {
            storeClientCopy(http->sc, entry,
                http->out.offset + size,
                http->out.offset,
                CLIENT_SOCK_SZ,
                buf,
                clientHandleIMSReply,
                http);
            return;
        }
    } else if (clientGetsOldEntry(entry, http->old_entry, http->request)) {
        /* We initiated the IMS request, the client is not expecting
         * 304, so put the good one back.  First, make sure the old entry
         * headers have been loaded from disk. */
        oldentry = http->old_entry;
        http->log_type = LOG_TCP_REFRESH_HIT;
        if (oldentry->mem_obj->request == NULL) {
            oldentry->mem_obj->request = requestLink(mem->request);
            unlink_request = 1;
        }
        /* Don't memcpy() the whole reply structure here.  For example,
         * www.thegist.com (Netscape/1.13) returns a content-length for
         * 304's which seems to be the length of the 304 HEADERS!!! and
         * not the body they refer to.  */
        httpReplyUpdateOnNotModified(oldentry->mem_obj->reply, mem->reply);
        storeTimestampsSet(oldentry);
        storeUnregister(http->sc, entry, http);
        http->sc = http->old_sc;
        storeUnlockObject(entry);
        entry = http->entry = oldentry;
        entry->timestamp = squid_curtime;
        if (unlink_request) {
            requestUnlink(entry->mem_obj->request);
            entry->mem_obj->request = NULL;
        }
    } else {
        /* the client can handle this reply, whatever it is */
        http->log_type = LOG_TCP_REFRESH_MISS;
        if (HTTP_NOT_MODIFIED == mem->reply->sline.status) {
            httpReplyUpdateOnNotModified(http->old_entry->mem_obj->reply,
                mem->reply);
            storeTimestampsSet(http->old_entry);
            http->log_type = LOG_TCP_REFRESH_HIT;
        }
        storeUnregister(http->old_sc, http->old_entry, http);
        storeUnlockObject(http->old_entry);
        recopy = 0;
    }
    http->old_entry = NULL;     /* done with old_entry */
    http->old_sc = NULL;
    assert(!EBIT_TEST(entry->flags, ENTRY_ABORTED));
    if (recopy) {
        storeClientCopy(http->sc, entry,
            http->out.offset,
            http->out.offset,
            CLIENT_SOCK_SZ,
            buf,
            clientSendMoreData,
            http);
    } else {
        clientSendMoreData(data, buf, size);
    }
}

int
modifiedSince(StoreEntry * entry, request_t * request)
{
    int object_length;
    MemObject *mem = entry->mem_obj;
    time_t mod_time = entry->lastmod;
    debug(33, 3) ("modifiedSince: '%s'\n", storeUrl(entry));
    if (mod_time < 0)
        mod_time = entry->timestamp;
    debug(33, 3) ("modifiedSince: mod_time = %d\n", (int) mod_time);
    if (mod_time < 0)
        return 1;
    /* Find size of the object */
    object_length = mem->reply->content_length;
    if (object_length < 0)
        object_length = contentLen(entry);
    if (mod_time > request->ims) {
        debug(33, 3) ("--> YES: entry newer than client\n");
        return 1;
    } else if (mod_time < request->ims) {
        debug(33, 3) ("-->  NO: entry older than client\n");
        return 0;
    } else if (request->imslen < 0) {
        debug(33, 3) ("-->  NO: same LMT, no client length\n");
        return 0;
    } else if (request->imslen == object_length) {
        debug(33, 3) ("-->  NO: same LMT, same length\n");
        return 0;
    } else {
        debug(33, 3) ("--> YES: same LMT, different length\n");
        return 1;
    }
}

void
clientPurgeRequest(clientHttpRequest * http)
{
    StoreEntry *entry;
    ErrorState *err = NULL;
    HttpReply *r;
    http_status status;
    http_version_t version;
    debug(33, 3) ("Config2.onoff.enable_purge = %d\n", Config2.onoff.enable_purge);
    if (!Config2.onoff.enable_purge) {
        http->log_type = LOG_TCP_DENIED;
        err = errorCon(ERR_ACCESS_DENIED, HTTP_FORBIDDEN);
        err->request = requestLink(http->request);
        err->src_addr = http->conn->peer.sin_addr;
        http->entry = clientCreateStoreEntry(http, http->request->method, null_request_flags);
        errorAppendEntry(http->entry, err);
        return;
    }
    http->log_type = LOG_TCP_MISS;
    /* Release both IP and object cache entries */
    ipcacheInvalidate(http->request->host);
    if ((entry = storeGetPublic(http->uri, METHOD_GET)) == NULL) {
        status = HTTP_NOT_FOUND;
    } else {
        storeRelease(entry);
        status = HTTP_OK;
    }
    debug(33, 4) ("clientPurgeRequest: Not modified '%s'\n",
        storeUrl(entry));
    /*
     * Make a new entry to hold the reply to be written
     * to the client.
     */
    http->entry = clientCreateStoreEntry(http, http->request->method, null_request_flags);
    httpReplyReset(r = http->entry->mem_obj->reply);
    httpBuildVersion(&version, 1, 0);
    httpReplySetHeaders(r, version, status, NULL, NULL, 0, 0, -1);
    httpReplySwapOut(r, http->entry);
    storeComplete(http->entry);
}

int
checkNegativeHit(StoreEntry * e)
{
    if (!EBIT_TEST(e->flags, ENTRY_NEGCACHED))
        return 0;
    if (e->expires <= squid_curtime)
        return 0;
    if (e->store_status != STORE_OK)
        return 0;
    return 1;
}

void
clientUpdateCounters(clientHttpRequest * http)
{
    int svc_time = tvSubMsec(http->start, current_time);
    ping_data *i;
    HierarchyLogEntry *H;
    statCounter.client_http.requests++;
    if (isTcpHit(http->log_type))
        statCounter.client_http.hits++;
    if (http->log_type == LOG_TCP_HIT)
        statCounter.client_http.disk_hits++;
    else if (http->log_type == LOG_TCP_MEM_HIT)
        statCounter.client_http.mem_hits++;
    if (http->request->err_type != ERR_NONE)
        statCounter.client_http.errors++;
    statHistCount(&statCounter.client_http.all_svc_time, svc_time);
    /*
     * The idea here is not to be complete, but to get service times
     * for only well-defined types.  For example, we don't include
     * LOG_TCP_REFRESH_FAIL_HIT because its not really a cache hit
     * (we *tried* to validate it, but failed).
     */
    switch (http->log_type) {
    case LOG_TCP_REFRESH_HIT:
        statHistCount(&statCounter.client_http.nh_svc_time, svc_time);
        break;
    case LOG_TCP_IMS_HIT:
        statHistCount(&statCounter.client_http.nm_svc_time, svc_time);
        break;
    case LOG_TCP_HIT:
    case LOG_TCP_MEM_HIT:
    case LOG_TCP_OFFLINE_HIT:
        statHistCount(&statCounter.client_http.hit_svc_time, svc_time);
        break;
    case LOG_TCP_MISS:
    case LOG_TCP_CLIENT_REFRESH_MISS:
        statHistCount(&statCounter.client_http.miss_svc_time, svc_time);
        break;
    default:
        /* make compiler warnings go away */
        break;
    }
    H = &http->request->hier;
    switch (H->alg) {
    case PEER_SA_DIGEST:
        statCounter.cd.times_used++;
        break;
    case PEER_SA_ICP:
        statCounter.icp.times_used++;
        i = &H->ping;
        if (0 != i->stop.tv_sec && 0 != i->start.tv_sec)
            statHistCount(&statCounter.icp.query_svc_time,
                tvSubUsec(i->start, i->stop));
        if (i->timeout)
            statCounter.icp.query_timeouts++;
        break;
    case PEER_SA_NETDB:
        statCounter.netdb.times_used++;
        break;
    default:
        break;
    }
}

static void
httpRequestFree(void *data)
{
    clientHttpRequest *http = data;
    clientHttpRequest **H;
    ConnStateData *conn = http->conn;
    StoreEntry *e;
    request_t *request = http->request;
    MemObject *mem = NULL;
    debug(33, 3) ("httpRequestFree: %s\n", storeUrl(http->entry));
    if (!clientCheckTransferDone(http)) {
#if MYSTERIOUS_CODE
        /*
         * DW: this seems odd here, is it really needed?  It causes
         * incomplete transfers to get logged with "000" status
         * code because http->entry becomes NULL.
         */
        if ((e = http->entry)) {
            http->entry = NULL;
            storeUnregister(http->sc, e, http);
            storeUnlockObject(e);
        }
#endif
        if (http->entry && http->entry->ping_status == PING_WAITING)
            storeReleaseRequest(http->entry);
    }
    assert(http->log_type < LOG_TYPE_MAX);
    if (http->entry)
        mem = http->entry->mem_obj;
    if (http->out.size || http->log_type) {
        http->al.icp.opcode = ICP_INVALID;
        http->al.url = http->log_uri;
        debug(33, 9) ("httpRequestFree: al.url='%s'\n", http->al.url);
        if (mem) {
            http->al.http.code = mem->reply->sline.status;
            http->al.http.content_type = strBuf(mem->reply->content_type);
        }
        http->al.cache.caddr = conn->log_addr;
        http->al.cache.size = http->out.size;
        http->al.cache.code = http->log_type;
        http->al.cache.msec = tvSubMsec(http->start, current_time);
        if (request) {
            Packer p;
            MemBuf mb;
            memBufDefInit(&mb);
            packerToMemInit(&p, &mb);
            httpHeaderPackInto(&request->header, &p);
            http->al.http.method = request->method;
            http->al.http.version = request->http_ver;
            http->al.headers.request = xstrdup(mb.buf);
            http->al.hier = request->hier;
            if (request->user_ident[0])
                http->al.cache.ident = request->user_ident;
            else
                http->al.cache.ident = conn->ident;
            packerClean(&p);
            memBufClean(&mb);
        }
        accessLogLog(&http->al);
        clientUpdateCounters(http);
        clientdbUpdate(conn->peer.sin_addr, http->log_type, PROTO_HTTP, http->out.size);
    }
    if (http->acl_checklist)
        aclChecklistFree(http->acl_checklist);
    if (request)
        checkFailureRatio(request->err_type, http->al.hier.code);
    safe_free(http->uri);
    safe_free(http->log_uri);
    safe_free(http->al.headers.request);
    safe_free(http->al.headers.reply);
    safe_free(http->redirect.location);
    stringClean(&http->range_iter.boundary);
    if ((e = http->entry)) {
        http->entry = NULL;
        storeUnregister(http->sc, e, http);
        http->sc = NULL;
        storeUnlockObject(e);
    }
    /* old_entry might still be set if we didn't yet get the reply
     * code in clientHandleIMSReply() */
    if ((e = http->old_entry)) {
        http->old_entry = NULL;
        storeUnregister(http->old_sc, e, http);
        http->old_sc = NULL;
        storeUnlockObject(e);
    }
    requestUnlink(http->request);
    assert(http != http->next);
    assert(http->conn->chr != NULL);
    H = &http->conn->chr;
    while (*H) {
        if (*H == http)
            break;
        H = &(*H)->next;
    }
    assert(*H != NULL);
    *H = http->next;
    http->next = NULL;
    dlinkDelete(&http->active, &ClientActiveRequests);
    cbdataFree(http);
}

/* This is a handler normally called by comm_close() */
static void
connStateFree(int fd, void *data)
{
    ConnStateData *connState = data;
    clientHttpRequest *http;
    debug(33, 3) ("connStateFree: FD %d\n", fd);
    assert(connState != NULL);
    clientdbEstablished(connState->peer.sin_addr, -1);  /* decrement */
    while ((http = connState->chr) != NULL) {
        assert(http->conn == connState);
        assert(connState->chr != connState->chr->next);
        httpRequestFree(http);
    }
    if (connState->in.size == CLIENT_REQ_BUF_SZ)
        memFree(connState->in.buf, MEM_CLIENT_REQ_BUF);
    else
        safe_free(connState->in.buf);
    /* XXX account connState->in.buf */
    pconnHistCount(0, connState->nrequests);
    cbdataFree(connState);
#ifdef _SQUID_LINUX_
    /* prevent those nasty RST packets */
    {
        char buf[SQUID_TCP_SO_RCVBUF];
        while (read(fd, buf, SQUID_TCP_SO_RCVBUF) > 0);
    }
#endif
}

static void
clientInterpretRequestHeaders(clientHttpRequest * http)
{
    request_t *request = http->request;
    const HttpHeader *req_hdr = &request->header;
    int no_cache = 0;
    const char *str;
    request->imslen = -1;
    request->ims = httpHeaderGetTime(req_hdr, HDR_IF_MODIFIED_SINCE);
    if (request->ims > 0)
        request->flags.ims = 1;
    if (httpHeaderHas(req_hdr, HDR_PRAGMA)) {
        String s = httpHeaderGetList(req_hdr, HDR_PRAGMA);
        if (strListIsMember(&s, "no-cache", ','))
            no_cache++;
        stringClean(&s);
    }
    request->cache_control = httpHeaderGetCc(req_hdr);
    if (request->cache_control)
        if (EBIT_TEST(request->cache_control->mask, CC_NO_CACHE))
            no_cache++;
    /* Work around for supporting the Reload button in IE browsers
     * when Squid is used as an accelerator or transparent proxy,
     * by turning accelerated IMS request to no-cache requests.
     * Now knows about IE 5.5 fix (is actually only fixed in SP1, 
     * but we can't tell whether we are talking to SP1 or not so 
     * all 5.5 versions are treated 'normally').
    */
    if (Config.onoff.ie_refresh) {
        if (http->flags.accel && request->flags.ims) {
           if ( (str = httpHeaderGetStr(req_hdr, HDR_USER_AGENT)) ) {
               if (strstr(str, "MSIE 5.01") != NULL)
                   no_cache++;
               else if (strstr(str, "MSIE 5.0") != NULL)
                   no_cache++;
               else if (strstr(str, "MSIE 4.") != NULL)
                   no_cache++;
               else if (strstr(str, "MSIE 3.") != NULL)
                   no_cache++;
            }
        }
    }

    if (no_cache) {
#if HTTP_VIOLATIONS
        if (Config.onoff.reload_into_ims)
            request->flags.nocache_hack = 1;
        else if (refresh_nocache_hack)
            request->flags.nocache_hack = 1;
        else
#endif
            request->flags.nocache = 1;
    }
    /* ignore range header in non-GETs */
    if (request->method == METHOD_GET) {
        request->range = httpHeaderGetRange(req_hdr);
        if (request->range)
            request->flags.range = 1;
    }
    if (httpHeaderHas(req_hdr, HDR_AUTHORIZATION))
        request->flags.auth = 1;
    if (request->login[0] != '\0')
        request->flags.auth = 1;
    if (httpHeaderHas(req_hdr, HDR_VIA)) {
        String s = httpHeaderGetList(req_hdr, HDR_VIA);
        /*
         * ThisCache cannot be a member of Via header, "1.0 ThisCache" can.
         * Note ThisCache2 has a space prepended to the hostname so we don't
         * accidentally match super-domains.
         */
        if (strListIsSubstr(&s, ThisCache2, ',')) {
            debugObj(33, 1, "WARNING: Forwarding loop detected for:\n",
                request, (ObjPackMethod) & httpRequestPack);
            request->flags.loopdetect = 1;
        }
#if FORW_VIA_DB
        fvdbCountVia(strBuf(s));
#endif
        stringClean(&s);
    }
#if USE_USERAGENT_LOG
    if ((str = httpHeaderGetStr(req_hdr, HDR_USER_AGENT)))
        logUserAgent(fqdnFromAddr(http->conn->peer.sin_addr), str);
#endif
#if USE_REFERER_LOG
    if ((str = httpHeaderGetStr(req_hdr, HDR_REFERER)))
        logReferer(fqdnFromAddr(http->conn->peer.sin_addr), str,
            http->log_uri);
#endif
#if FORW_VIA_DB
    if (httpHeaderHas(req_hdr, HDR_X_FORWARDED_FOR)) {
        String s = httpHeaderGetList(req_hdr, HDR_X_FORWARDED_FOR);
        fvdbCountForw(strBuf(s));
        stringClean(&s);
    }
#endif
    if (request->method == METHOD_TRACE) {
        request->max_forwards = httpHeaderGetInt(req_hdr, HDR_MAX_FORWARDS);
    }
    if (clientCachable(http))
        request->flags.cachable = 1;
    if (clientHierarchical(http))
        request->flags.hierarchical = 1;
    debug(33, 5) ("clientInterpretRequestHeaders: REQ_NOCACHE = %s\n",
        request->flags.nocache ? "SET" : "NOT SET");
    debug(33, 5) ("clientInterpretRequestHeaders: REQ_CACHABLE = %s\n",
        request->flags.cachable ? "SET" : "NOT SET");
    debug(33, 5) ("clientInterpretRequestHeaders: REQ_HIERARCHICAL = %s\n",
        request->flags.hierarchical ? "SET" : "NOT SET");
}

/*
 * clientSetKeepaliveFlag() sets request->flags.proxy_keepalive.
 * This is the client-side persistent connection flag.  We need
 * to set this relatively early in the request processing
 * to handle hacks for broken servers and clients.
 */
static void
clientSetKeepaliveFlag(clientHttpRequest * http)
{
    request_t *request = http->request;
    const HttpHeader *req_hdr = &request->header;
    debug(33, 3) ("clientSetKeepaliveFlag: http_ver = %d.%d\n",
        request->http_ver.major, request->http_ver.minor);
    debug(33, 3) ("clientSetKeepaliveFlag: method = %s\n",
        RequestMethodStr[request->method]);
    if (!Config.onoff.client_pconns)
        request->flags.proxy_keepalive = 0;
    else if (httpMsgIsPersistent(request->http_ver, req_hdr))
        request->flags.proxy_keepalive = 1;
}

static int
clientCheckContentLength(request_t * r)
{
    switch (r->method) {
    case METHOD_PUT:
    case METHOD_POST:
        /* PUT/POST requires a request entity */
        return (r->content_length >= 0);
    case METHOD_GET:
    case METHOD_HEAD:
        /* We do not want to see a request entity on GET/HEAD requests */
        return (r->content_length <= 0);
    default:
        /* For other types of requests we don't care */
        return 1;
    }
    /* NOT REACHED */
}

static int
clientCachable(clientHttpRequest * http)
{
    const char *url = http->uri;
    request_t *req = http->request;
    method_t method = req->method;
    if (req->protocol == PROTO_HTTP)
        return httpCachable(method);
    /* FTP is always cachable */
    if (req->protocol == PROTO_GOPHER)
        return gopherCachable(url);
    if (req->protocol == PROTO_WAIS)
        return 0;
    if (method == METHOD_CONNECT)
        return 0;
    if (method == METHOD_TRACE)
        return 0;
    if (req->protocol == PROTO_CACHEOBJ)
        return 0;
    return 1;
}

/* Return true if we can query our neighbors for this object */
static int
clientHierarchical(clientHttpRequest * http)
{
    const char *url = http->uri;
    request_t *request = http->request;
    method_t method = request->method;
    const wordlist *p = NULL;

    /* IMS needs a private key, so we can use the hierarchy for IMS only
     * if our neighbors support private keys */
    if (request->flags.ims && !neighbors_do_private_keys)
        return 0;
    if (request->flags.auth)
        return 0;
    if (method == METHOD_TRACE)
        return 1;
    if (method != METHOD_GET)
        return 0;
    /* scan hierarchy_stoplist */
    for (p = Config.hierarchy_stoplist; p; p = p->next)
        if (strstr(url, p->key))
            return 0;
    if (request->flags.loopdetect)
        return 0;
    if (request->protocol == PROTO_HTTP)
        return httpCachable(method);
    if (request->protocol == PROTO_GOPHER)
        return gopherCachable(url);
    if (request->protocol == PROTO_WAIS)
        return 0;
    if (request->protocol == PROTO_CACHEOBJ)
        return 0;
    return 1;
}

int
isTcpHit(log_type code)
{
    /* this should be a bitmap for better optimization */
    if (code == LOG_TCP_HIT)
        return 1;
    if (code == LOG_TCP_IMS_HIT)
        return 1;
    if (code == LOG_TCP_REFRESH_FAIL_HIT)
        return 1;
    if (code == LOG_TCP_REFRESH_HIT)
        return 1;
    if (code == LOG_TCP_NEGATIVE_HIT)
        return 1;
    if (code == LOG_TCP_MEM_HIT)
        return 1;
    if (code == LOG_TCP_OFFLINE_HIT)
        return 1;
    return 0;
}

/*
 * returns true if If-Range specs match reply, false otherwise
 */
static int
clientIfRangeMatch(clientHttpRequest * http, HttpReply * rep)
{
    const TimeOrTag spec = httpHeaderGetTimeOrTag(&http->request->header, HDR_IF_RANGE);
    /* check for parsing falure */
    if (!spec.valid)
        return 0;
    /* got an ETag? */
    if (spec.tag.str) {
        ETag rep_tag = httpHeaderGetETag(&rep->header, HDR_ETAG);
        debug(33, 3) ("clientIfRangeMatch: ETags: %s and %s\n",
            spec.tag.str, rep_tag.str ? rep_tag.str : "<none>");
        if (!rep_tag.str)
            return 0;           /* entity has no etag to compare with! */
        if (spec.tag.weak || rep_tag.weak) {
            debug(33, 1) ("clientIfRangeMatch: Weak ETags are not allowed in If-Range: %s ? %s\n",
                spec.tag.str, rep_tag.str);
            return 0;           /* must use strong validator for sub-range requests */
        }
        return etagIsEqual(&rep_tag, &spec.tag);
    }
    /* got modification time? */
    if (spec.time >= 0) {
        return http->entry->lastmod <= spec.time;
    }
    assert(0);                  /* should not happen */
    return 0;
}

/* returns expected content length for multi-range replies
 * note: assumes that httpHdrRangeCanonize has already been called
 * warning: assumes that HTTP headers for individual ranges at the
 *          time of the actuall assembly will be exactly the same as
 *          the headers when clientMRangeCLen() is called */
static int
clientMRangeCLen(clientHttpRequest * http)
{
    int clen = 0;
    HttpHdrRangePos pos = HttpHdrRangeInitPos;
    const HttpHdrRangeSpec *spec;
    MemBuf mb;

    assert(http->entry->mem_obj);

    memBufDefInit(&mb);
    while ((spec = httpHdrRangeGetSpec(http->request->range, &pos))) {

        /* account for headers for this range */
        memBufReset(&mb);
        clientPackRangeHdr(http->entry->mem_obj->reply,
            spec, http->range_iter.boundary, &mb);
        clen += mb.size;

        /* account for range content */
        clen += spec->length;

        debug(33, 6) ("clientMRangeCLen: (clen += %d + %d) == %d\n",
            mb.size, spec->length, clen);
    }
    /* account for the terminating boundary */
    memBufReset(&mb);
    clientPackTermBound(http->range_iter.boundary, &mb);
    clen += mb.size;

    memBufClean(&mb);
    return clen;
}

/* adds appropriate Range headers if needed */
static void
clientBuildRangeHeader(clientHttpRequest * http, HttpReply * rep)
{
    HttpHeader *hdr = rep ? &rep->header : 0;
    const char *range_err = NULL;
    request_t *request = http->request;
    assert(request->range);
    /* check if we still want to do ranges */
    if (!rep)
        range_err = "no [parse-able] reply";
    else if (rep->sline.status != HTTP_OK)
        range_err = "wrong status code";
    else if (httpHeaderHas(hdr, HDR_CONTENT_RANGE))
        range_err = "origin server does ranges";
    else if (rep->content_length < 0)
        range_err = "unknown length";
    else if (rep->content_length != http->entry->mem_obj->reply->content_length)
        range_err = "INCONSISTENT length";      /* a bug? */
    else if (httpHeaderHas(&http->request->header, HDR_IF_RANGE) && !clientIfRangeMatch(http, rep))
        range_err = "If-Range match failed";
    else if (!httpHdrRangeCanonize(http->request->range, rep->content_length))
        range_err = "canonization failed";
    else if (httpHdrRangeIsComplex(http->request->range))
        range_err = "too complex range header";
    else if (!request->flags.cachable)  /* from we_do_ranges in http.c */
        range_err = "non-cachable request";
    /* get rid of our range specs on error */
    if (range_err) {
        debug(33, 3) ("clientBuildRangeHeader: will not do ranges: %s.\n", range_err);
        httpHdrRangeDestroy(http->request->range);
        http->request->range = NULL;
    } else {
        const int spec_count = http->request->range->specs.count;
        int actual_clen = -1;

        debug(33, 3) ("clientBuildRangeHeader: range spec count: %d virgin clen: %d\n",
            spec_count, rep->content_length);
        assert(spec_count > 0);
        /* ETags should not be returned with Partial Content replies? */
        httpHeaderDelById(hdr, HDR_ETAG);
        /* append appropriate header(s) */
        if (spec_count == 1) {
            HttpHdrRangePos pos = HttpHdrRangeInitPos;
            const HttpHdrRangeSpec *spec = httpHdrRangeGetSpec(http->request->range, &pos);
            assert(spec);
            /* append Content-Range */
            httpHeaderAddContRange(hdr, *spec, rep->content_length);
            /* set new Content-Length to the actual number of bytes
             * transmitted in the message-body */
            actual_clen = spec->length;
        } else {
            /* multipart! */
            /* generate boundary string */
            http->range_iter.boundary = httpHdrRangeBoundaryStr(http);
            /* delete old Content-Type, add ours */
            httpHeaderDelById(hdr, HDR_CONTENT_TYPE);
            httpHeaderPutStrf(hdr, HDR_CONTENT_TYPE,
                "multipart/byteranges; boundary=\"%s\"",
                strBuf(http->range_iter.boundary));
            /* Content-Length is not required in multipart responses
             * but it is always nice to have one */
            actual_clen = clientMRangeCLen(http);
        }

        /* replace Content-Length header */
        assert(actual_clen >= 0);
        httpHeaderDelById(hdr, HDR_CONTENT_LENGTH);
        httpHeaderPutInt(hdr, HDR_CONTENT_LENGTH, actual_clen);
        debug(33, 3) ("clientBuildRangeHeader: actual content length: %d\n", actual_clen);
    }
}

/*
 * filters out unwanted entries from original reply header
 * adds extra entries if we have more info than origin server
 * adds Squid specific entries
 */
static void
clientBuildReplyHeader(clientHttpRequest * http, HttpReply * rep)
{
    HttpHeader *hdr = &rep->header;
    int is_hit = isTcpHit(http->log_type);
    request_t *request = http->request;
#if DONT_FILTER_THESE
    /* but you might want to if you run Squid as an HTTP accelerator */
    /* httpHeaderDelById(hdr, HDR_ACCEPT_RANGES); */
    httpHeaderDelById(hdr, HDR_ETAG);
#endif
    httpHeaderDelById(hdr, HDR_PROXY_CONNECTION);
    /* here: Keep-Alive is a field-name, not a connection directive! */
    httpHeaderDelByName(hdr, "Keep-Alive");
    /* remove Set-Cookie if a hit */
    if (is_hit)
        httpHeaderDelById(hdr, HDR_SET_COOKIE);
    /* handle Connection header */
    if (httpHeaderHas(hdr, HDR_CONNECTION)) {
        /* anything that matches Connection list member will be deleted */
        String strConnection = httpHeaderGetList(hdr, HDR_CONNECTION);
        const HttpHeaderEntry *e;
        HttpHeaderPos pos = HttpHeaderInitPos;
        /*
         * think: on-average-best nesting of the two loops (hdrEntry
         * and strListItem) @?@
         */
        /*
         * maybe we should delete standard stuff ("keep-alive","close")
         * from strConnection first?
         */
        while ((e = httpHeaderGetEntry(hdr, &pos))) {
            if (strListIsMember(&strConnection, strBuf(e->name), ','))
                httpHeaderDelAt(hdr, pos);
        }
        httpHeaderDelById(hdr, HDR_CONNECTION);
        stringClean(&strConnection);
    }
    /* Handle Ranges */
    if (request->range)
        clientBuildRangeHeader(http, rep);
    /*
     * Add a estimated Age header on cache hits.
     */
    if (is_hit) {
        /*
         * Remove any existing Age header sent by upstream caches
         * (note that the existing header is passed along unmodified
         * on cache misses)
         */
        httpHeaderDelById(hdr, HDR_AGE);
        /*
         * This adds the calculated object age. Note that the details of the
         * age calculation is performed by adjusting the timestamp in
         * storeTimestampsSet(), not here.
         *
         * BROWSER WORKAROUND: IE sometimes hangs when receiving a 0 Age
         * header, so don't use it unless there is a age to report. Please
         * note that Age is only used to make a conservative estimation of
         * the objects age, so a Age: 0 header does not add any useful
         * information to the reply in any case.
         */
        if (http->entry->timestamp > -1)
            if (http->entry->timestamp < squid_curtime)
                httpHeaderPutInt(hdr, HDR_AGE,
                    squid_curtime - http->entry->timestamp);
    }
    /* Append X-Cache */
    httpHeaderPutStrf(hdr, HDR_X_CACHE, "%s from %s",
        is_hit ? "HIT" : "MISS", getMyHostname());
#if USE_CACHE_DIGESTS
    /* Append X-Cache-Lookup: -- temporary hack, to be removed @?@ @?@ */
    httpHeaderPutStrf(hdr, HDR_X_CACHE_LOOKUP, "%s from %s:%d",
        http->lookup_type ? http->lookup_type : "NONE",
        getMyHostname(), ntohs(Config.Sockaddr.http->s.sin_port));
#endif
    if (httpReplyBodySize(request->method, rep) < 0) {
        debug(33, 3) ("clientBuildReplyHeader: can't keep-alive, unknown body size\n");
        request->flags.proxy_keepalive = 0;
    }
    /* Signal keep-alive if needed */
    httpHeaderPutStr(hdr,
        http->flags.accel ? HDR_CONNECTION : HDR_PROXY_CONNECTION,
        request->flags.proxy_keepalive ? "keep-alive" : "close");
#if ADD_X_REQUEST_URI
    /*
     * Knowing the URI of the request is useful when debugging persistent
     * connections in a client; we cannot guarantee the order of http headers,
     * but X-Request-URI is likely to be the very last header to ease use from a
     * debugger [hdr->entries.count-1].
     */
    httpHeaderPutStr(hdr, HDR_X_REQUEST_URI,
        http->entry->mem_obj->url ? http->entry->mem_obj->url : http->uri);
#endif
}

static HttpReply *
clientBuildReply(clientHttpRequest * http, const char *buf, size_t size)
{
    HttpReply *rep = httpReplyCreate();
    size_t k = headersEnd(buf, size);
    if (k && httpReplyParse(rep, buf, k)) {
        /* enforce 1.0 reply version */
        httpBuildVersion(&rep->sline.version, 1, 0);
        /* do header conversions */
        clientBuildReplyHeader(http, rep);
        /* if we do ranges, change status to "Partial Content" */
        if (http->request->range)
            httpStatusLineSet(&rep->sline, rep->sline.version,
                HTTP_PARTIAL_CONTENT, NULL);
    } else {
        /* parsing failure, get rid of the invalid reply */
        httpReplyDestroy(rep);
        rep = NULL;
        /* if we were going to do ranges, backoff */
        if (http->request->range) {
            /* this will fail and destroy request->range */
            clientBuildRangeHeader(http, rep);
        }
    }
    return rep;
}

/*
 * clientCacheHit should only be called until the HTTP reply headers
 * have been parsed.  Normally this should be a single call, but
 * it might take more than one.  As soon as we have the headers,
 * we hand off to clientSendMoreData, clientProcessExpired, or
 * clientProcessMiss.
 */
static void
clientCacheHit(void *data, char *buf, ssize_t size)
{
    clientHttpRequest *http = data;
    StoreEntry *e = http->entry;
    MemObject *mem;
    request_t *r = http->request;
    debug(33, 3) ("clientCacheHit: %s, %d bytes\n", http->uri, (int) size);
    if (http->entry == NULL) {
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        debug(33, 3) ("clientCacheHit: request aborted\n");
        return;
    } else if (size < 0) {
        /* swap in failure */
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        debug(33, 3) ("clientCacheHit: swapin failure for %s\n", http->uri);
        http->log_type = LOG_TCP_SWAPFAIL_MISS;
        if ((e = http->entry)) {
            http->entry = NULL;
            storeUnregister(http->sc, e, http);
            http->sc = NULL;
            storeUnlockObject(e);
        }
        clientProcessMiss(http);
        return;
    }
    assert(size > 0);
    mem = e->mem_obj;
    assert(!EBIT_TEST(e->flags, ENTRY_ABORTED));
    if (mem->reply->sline.status == 0) {
        /*
         * we don't have full reply headers yet; either wait for more or
         * punt to clientProcessMiss.
         */
        if (e->mem_status == IN_MEMORY || e->store_status == STORE_OK) {
            memFree(buf, MEM_CLIENT_SOCK_BUF);
            clientProcessMiss(http);
        } else if (size == CLIENT_SOCK_SZ && http->out.offset == 0) {
            memFree(buf, MEM_CLIENT_SOCK_BUF);
            clientProcessMiss(http);
        } else {
            debug(33, 3) ("clientCacheHit: waiting for HTTP reply headers\n");
            storeClientCopy(http->sc, e,
                http->out.offset + size,
                http->out.offset,
                CLIENT_SOCK_SZ,
                buf,
                clientCacheHit,
                http);
        }
        return;
    }
    /*
     * Got the headers, now grok them
     */
    assert(http->log_type == LOG_TCP_HIT);
    if (checkNegativeHit(e)) {
        http->log_type = LOG_TCP_NEGATIVE_HIT;
        clientSendMoreData(data, buf, size);
    } else if (r->method == METHOD_HEAD) {
        /*
         * RFC 2068 seems to indicate there is no "conditional HEAD"
         * request.  We cannot validate a cached object for a HEAD
         * request, nor can we return 304.
         */
        if (e->mem_status == IN_MEMORY)
            http->log_type = LOG_TCP_MEM_HIT;
        clientSendMoreData(data, buf, size);
    } else if (refreshCheckHTTP(e, r) && !http->flags.internal) {
        debug(33, 5) ("clientCacheHit: in refreshCheck() block\n");
        /*
         * We hold a stale copy; it needs to be validated
         */
        /*
         * The 'need_validation' flag is used to prevent forwarding
         * loops between siblings.  If our copy of the object is stale,
         * then we should probably only use parents for the validation
         * request.  Otherwise two siblings could generate a loop if
         * both have a stale version of the object.
         */
        r->flags.need_validation = 1;
        if (e->lastmod < 0) {
            /*
             * Previous reply didn't have a Last-Modified header,
             * we cannot revalidate it.
             */
            http->log_type = LOG_TCP_MISS;
            clientProcessMiss(http);
        } else if (r->flags.nocache) {
            /*
             * This did not match a refresh pattern that overrides no-cache
             * we should honour the client no-cache header.
             */
            http->log_type = LOG_TCP_CLIENT_REFRESH_MISS;
            clientProcessMiss(http);
        } else if (r->protocol == PROTO_HTTP) {
            /*
             * Object needs to be revalidated
             * XXX This could apply to FTP as well, if Last-Modified is known.
             */
            http->log_type = LOG_TCP_REFRESH_MISS;
            clientProcessExpired(http);
        } else {
            /*
             * We don't know how to re-validate other protocols. Handle
             * them as if the object has expired.
             */
            http->log_type = LOG_TCP_MISS;
            clientProcessMiss(http);
        }
        memFree(buf, MEM_CLIENT_SOCK_BUF);
    } else if (r->flags.ims) {
        /*
         * Handle If-Modified-Since requests from the client
         */
        if (mem->reply->sline.status != HTTP_OK) {
            debug(33, 4) ("clientCacheHit: Reply code %d != 200\n",
                mem->reply->sline.status);
            memFree(buf, MEM_CLIENT_SOCK_BUF);
            http->log_type = LOG_TCP_MISS;
            clientProcessMiss(http);
        } else if (modifiedSince(e, http->request)) {
            http->log_type = LOG_TCP_IMS_HIT;
            clientSendMoreData(data, buf, size);
        } else {
            time_t timestamp = e->timestamp;
            MemBuf mb = httpPacked304Reply(e->mem_obj->reply);
            http->log_type = LOG_TCP_IMS_HIT;
            memFree(buf, MEM_CLIENT_SOCK_BUF);
            storeUnregister(http->sc, e, http);
            http->sc = NULL;
            storeUnlockObject(e);
            e = clientCreateStoreEntry(http, http->request->method, null_request_flags);
            /*
             * Copy timestamp from the original entry so the 304
             * reply has a meaningful Age: header.
             */
            e->timestamp = timestamp;
            http->entry = e;
            httpReplyParse(e->mem_obj->reply, mb.buf, mb.size);
            storeAppend(e, mb.buf, mb.size);
            memBufClean(&mb);
            storeComplete(e);
        }
    } else {
        /*
         * plain ol' cache hit
         */
        if (e->mem_status == IN_MEMORY)
            http->log_type = LOG_TCP_MEM_HIT;
        else if (Config.onoff.offline)
            http->log_type = LOG_TCP_OFFLINE_HIT;
        clientSendMoreData(data, buf, size);
    }
}

/* put terminating boundary for multiparts */
static void
clientPackTermBound(String boundary, MemBuf * mb)
{
    memBufPrintf(mb, "\r\n--%s--\r\n", strBuf(boundary));
    debug(33, 6) ("clientPackTermBound: buf offset: %d\n", mb->size);
}

/* appends a "part" HTTP header (as in a multi-part/range reply) to the buffer */
static void
clientPackRangeHdr(const HttpReply * rep, const HttpHdrRangeSpec * spec, String boundary, MemBuf * mb)
{
    HttpHeader hdr;
    Packer p;
    assert(rep);
    assert(spec);

    /* put boundary */
    debug(33, 5) ("clientPackRangeHdr: appending boundary: %s\n", strBuf(boundary));
    /* rfc2046 requires to _prepend_ boundary with <crlf>! */
    memBufPrintf(mb, "\r\n--%s\r\n", strBuf(boundary));

    /* stuff the header with required entries and pack it */
    httpHeaderInit(&hdr, hoReply);
    if (httpHeaderHas(&rep->header, HDR_CONTENT_TYPE))
        httpHeaderPutStr(&hdr, HDR_CONTENT_TYPE, httpHeaderGetStr(&rep->header, HDR_CONTENT_TYPE));
    httpHeaderAddContRange(&hdr, *spec, rep->content_length);
    packerToMemInit(&p, mb);
    httpHeaderPackInto(&hdr, &p);
    packerClean(&p);
    httpHeaderClean(&hdr);

    /* append <crlf> (we packed a header, not a reply) */
    memBufPrintf(mb, crlf);
}

/*
 * extracts a "range" from *buf and appends them to mb, updating
 * all offsets and such.
 */
static void
clientPackRange(clientHttpRequest * http,
    HttpHdrRangeIter * i,
    const char **buf,
    ssize_t * size,
    MemBuf * mb)
{
    const ssize_t copy_sz = i->debt_size <= *size ? i->debt_size : *size;
    off_t body_off = http->out.offset - i->prefix_size;
    assert(*size > 0);
    assert(i->spec);
    /*
     * intersection of "have" and "need" ranges must not be empty
     */
    assert(body_off < i->spec->offset + i->spec->length);
    assert(body_off + *size > i->spec->offset);
    /*
     * put boundary and headers at the beginning of a range in a
     * multi-range
     */
    if (http->request->range->specs.count > 1 && i->debt_size == i->spec->length) {
        assert(http->entry->mem_obj);
        clientPackRangeHdr(
            http->entry->mem_obj->reply,        /* original reply */
            i->spec,            /* current range */
            i->boundary,        /* boundary, the same for all */
            mb
            );
    }
    /*
     * append content
     */
    debug(33, 3) ("clientPackRange: appending %d bytes\n", copy_sz);
    memBufAppend(mb, *buf, copy_sz);
    /*
     * update offsets
     */
    *size -= copy_sz;
    i->debt_size -= copy_sz;
    body_off += copy_sz;
    *buf += copy_sz;
    http->out.offset = body_off + i->prefix_size;       /* sync */
    /*
     * paranoid check
     */
    assert(*size >= 0 && i->debt_size >= 0);
}

/* returns true if there is still data available to pack more ranges
 * increments iterator "i"
 * used by clientPackMoreRanges */
static int
clientCanPackMoreRanges(const clientHttpRequest * http, HttpHdrRangeIter * i, ssize_t size)
{
    /* first update "i" if needed */
    if (!i->debt_size) {
        if ((i->spec = httpHdrRangeGetSpec(http->request->range, &i->pos)))
            i->debt_size = i->spec->length;
    }
    assert(!i->debt_size == !i->spec);  /* paranoid sync condition */
    /* continue condition: need_more_data && have_more_data */
    return i->spec && size > 0;
}

/* extracts "ranges" from buf and appends them to mb, updating all offsets and such */
/* returns true if we need more data */
static int
clientPackMoreRanges(clientHttpRequest * http, const char *buf, ssize_t size, MemBuf * mb)
{
    HttpHdrRangeIter *i = &http->range_iter;
    /* offset in range specs does not count the prefix of an http msg */
    off_t body_off = http->out.offset - i->prefix_size;
    assert(size >= 0);
    /* check: reply was parsed and range iterator was initialized */
    assert(i->prefix_size > 0);
    /* filter out data according to range specs */
    while (clientCanPackMoreRanges(http, i, size)) {
        off_t start;            /* offset of still missing data */
        assert(i->spec);
        start = i->spec->offset + i->spec->length - i->debt_size;
        debug(33, 3) ("clientPackMoreRanges: in:  offset: %d size: %d\n",
            (int) body_off, size);
        debug(33, 3) ("clientPackMoreRanges: out: start: %d spec[%d]: [%d, %d), len: %d debt: %d\n",
            (int) start, (int) i->pos, i->spec->offset, (int) (i->spec->offset + i->spec->length), i->spec->length, i->debt_size);
        assert(body_off <= start);      /* we did not miss it */
        /* skip up to start */
        if (body_off + size > start) {
            const size_t skip_size = start - body_off;
            body_off = start;
            size -= skip_size;
            buf += skip_size;
        } else {
            /* has not reached start yet */
            body_off += size;
            size = 0;
            buf = NULL;
        }
        /* put next chunk if any */
        if (size) {
            http->out.offset = body_off + i->prefix_size;       /* sync */
            clientPackRange(http, i, &buf, &size, mb);
            body_off = http->out.offset - i->prefix_size;       /* sync */
        }
    }
    assert(!i->debt_size == !i->spec);  /* paranoid sync condition */
    debug(33, 3) ("clientPackMoreRanges: buf exhausted: in:  offset: %d size: %d need_more: %d\n",
        (int) body_off, size, i->debt_size);
    if (i->debt_size) {
        debug(33, 3) ("clientPackMoreRanges: need more: spec[%d]: [%d, %d), len: %d\n",
            (int) i->pos, i->spec->offset, (int) (i->spec->offset + i->spec->length), i->spec->length);
        /* skip the data we do not need if possible */
        if (i->debt_size == i->spec->length)    /* at the start of the cur. spec */
            body_off = i->spec->offset;
        else
            assert(body_off == i->spec->offset + i->spec->length - i->debt_size);
    } else if (http->request->range->specs.count > 1) {
        /* put terminating boundary for multiparts */
        clientPackTermBound(i->boundary, mb);
    }
    http->out.offset = body_off + i->prefix_size;       /* sync */
    return i->debt_size > 0;
}

static int
clientReplyBodyTooLarge(int clen)
{
    if (0 == Config.maxReplyBodySize)
        return 0;               /* disabled */
    if (clen < 0)
        return 0;               /* unknown */
    if (clen > Config.maxReplyBodySize)
        return 1;               /* too large */
    return 0;
}

static int
clientRequestBodyTooLarge(int clen)
{
    if (0 == Config.maxRequestBodySize)
        return 0;               /* disabled */
    if (clen < 0)
        return 0;               /* unknown, bug? */
    if (clen > Config.maxRequestBodySize)
        return 1;               /* too large */
    return 0;
}

/*
 * accepts chunk of a http message in buf, parses prefix, filters headers and
 * such, writes processed message to the client's socket
 */
static void
clientSendMoreData(void *data, char *buf, ssize_t size)
{
    clientHttpRequest *http = data;
    StoreEntry *entry = http->entry;
    ConnStateData *conn = http->conn;
    int fd = conn->fd;
    HttpReply *rep = NULL;
    const char *body_buf = buf;
    ssize_t body_size = size;
    MemBuf mb;
    ssize_t check_size = 0;
    debug(33, 5) ("clientSendMoreData: %s, %d bytes\n", http->uri, (int) size);
    assert(size <= CLIENT_SOCK_SZ);
    assert(http->request != NULL);
    dlinkDelete(&http->active, &ClientActiveRequests);
    dlinkAdd(http, &http->active, &ClientActiveRequests);
    debug(33, 5) ("clientSendMoreData: FD %d '%s', out.offset=%d \n",
        fd, storeUrl(entry), (int) http->out.offset);
    if (conn->chr != http) {
        /* there is another object in progress, defer this one */
        debug(33, 1) ("clientSendMoreData: Deferring %s\n", storeUrl(entry));
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    } else if (entry && EBIT_TEST(entry->flags, ENTRY_ABORTED)) {
        /* call clientWriteComplete so the client socket gets closed */
        clientWriteComplete(fd, NULL, 0, COMM_OK, http);
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    } else if (size < 0) {
        /* call clientWriteComplete so the client socket gets closed */
        clientWriteComplete(fd, NULL, 0, COMM_OK, http);
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    } else if (size == 0) {
        /* call clientWriteComplete so the client socket gets closed */
        clientWriteComplete(fd, NULL, 0, COMM_OK, http);
        memFree(buf, MEM_CLIENT_SOCK_BUF);
        return;
    }
    if (http->out.offset == 0) {
        if (Config.onoff.log_mime_hdrs) {
            size_t k;
            if ((k = headersEnd(buf, size))) {
                safe_free(http->al.headers.reply);
                http->al.headers.reply = xcalloc(k + 1, 1);
                xstrncpy(http->al.headers.reply, buf, k);
            }
        }
        rep = clientBuildReply(http, buf, size);
        if (rep && clientReplyBodyTooLarge(rep->content_length)) {
            ErrorState *err = errorCon(ERR_TOO_BIG, HTTP_FORBIDDEN);
            err->request = requestLink(http->request);
            storeUnregister(http->sc, http->entry, http);
            http->sc = NULL;
            storeUnlockObject(http->entry);
            http->entry = clientCreateStoreEntry(http, http->request->method,
                null_request_flags);
            errorAppendEntry(http->entry, err);
            httpReplyDestroy(rep);
            return;
        } else if (rep) {
            body_size = size - rep->hdr_sz;
            assert(body_size >= 0);
            body_buf = buf + rep->hdr_sz;
            http->range_iter.prefix_size = rep->hdr_sz;
            debug(33, 3) ("clientSendMoreData: Appending %d bytes after %d bytes of headers\n",
                body_size, rep->hdr_sz);
        } else if (size < CLIENT_SOCK_SZ && entry->store_status == STORE_PENDING) {
            /* wait for more to arrive */
            storeClientCopy(http->sc, entry,
                http->out.offset + size,
                http->out.offset,
                CLIENT_SOCK_SZ,
                buf,
                clientSendMoreData,
                http);
            return;
        }
        /* reset range iterator */
        http->range_iter.pos = HttpHdrRangeInitPos;
    } else if (!http->request->range) {
        /* Avoid copying to MemBuf for non-range requests */
        /* Note, if we're here, then 'rep' is known to be NULL */
        http->out.offset += body_size;
        comm_write(fd, buf, size, clientWriteBodyComplete, http, NULL);
        /* NULL because clientWriteBodyComplete frees it */
        return;
    }
    if (http->request->method == METHOD_HEAD) {
        if (rep) {
            /* do not forward body for HEAD replies */
            body_size = 0;
            http->flags.done_copying = 1;
        } else {
            /*
             * If we are here, then store_status == STORE_OK and it
             * seems we have a HEAD repsponse which is missing the
             * empty end-of-headers line (home.mira.net, phttpd/0.99.72
             * does this).  Because clientBuildReply() fails we just
             * call this reply a body, set the done_copying flag and
             * continue...
             */
            http->flags.done_copying = 1;
        }
    }
    /* write headers and/or body if any */
    assert(rep || (body_buf && body_size));
    /* init mb; put status line and headers if any */
    if (rep) {
        mb = httpReplyPack(rep);
        http->out.offset += rep->hdr_sz;
        check_size += rep->hdr_sz;
#if HEADERS_LOG
        headersLog(0, 0, http->request->method, rep);
#endif
        httpReplyDestroy(rep);
        rep = NULL;
    } else {
        memBufDefInit(&mb);
    }
    /* append body if any */
    if (http->request->range) {
        /* Only GET requests should have ranges */
        assert(http->request->method == METHOD_GET);
        /* clientPackMoreRanges() updates http->out.offset */
        /* force the end of the transfer if we are done */
        if (!clientPackMoreRanges(http, body_buf, body_size, &mb))
            http->flags.done_copying = 1;
    } else if (body_buf && body_size) {
        http->out.offset += body_size;
        check_size += body_size;
        memBufAppend(&mb, body_buf, body_size);
    }
    if (!http->request->range && http->request->method == METHOD_GET)
        assert(check_size == size);
    /* write */
    comm_write_mbuf(fd, mb, clientWriteComplete, http);
    /* if we don't do it, who will? */
    memFree(buf, MEM_CLIENT_SOCK_BUF);
}

/*
 * clientWriteBodyComplete is called for MEM_CLIENT_SOCK_BUF's
 * written directly to the client socket, versus copying to a MemBuf
 * and going through comm_write_mbuf.  Most non-range responses after
 * the headers probably go through here.
 */
static void
clientWriteBodyComplete(int fd, char *buf, size_t size, int errflag, void *data)
{
    /*
     * NOTE: clientWriteComplete doesn't currently use its "buf"
     * (second) argument, so we pass in NULL.
     */
    clientWriteComplete(fd, NULL, size, errflag, data);
    memFree(buf, MEM_CLIENT_SOCK_BUF);
}

static void
clientKeepaliveNextRequest(clientHttpRequest * http)
{
    ConnStateData *conn = http->conn;
    StoreEntry *entry;
    debug(33, 3) ("clientKeepaliveNextRequest: FD %d\n", conn->fd);
    conn->defer.until = 0;      /* Kick it to read a new request */
    httpRequestFree(http);
    if ((http = conn->chr) == NULL) {
        debug(33, 5) ("clientKeepaliveNextRequest: FD %d reading next req\n",
            conn->fd);
        fd_note(conn->fd, "Reading next request");
        /*
         * Set the timeout BEFORE calling clientReadRequest().
         */
        commSetTimeout(conn->fd, Config.Timeout.pconn, requestTimeout, conn);
        /*
         * CYGWIN has a problem and is blocking on read() requests when there
         * is no data present.
         * This hack may hit performance a little, but it's better than 
         * blocking!.
         */
#ifdef _SQUID_CYGWIN_
        commSetSelect(conn->fd, COMM_SELECT_READ, clientReadRequest, conn, 0);
#else
        clientReadRequest(conn->fd, conn);      /* Read next request */
#endif
        /*
         * Note, the FD may be closed at this point.
         */
    } else if ((entry = http->entry) == NULL) {
        /*
         * this request is in progress, maybe doing an ACL or a redirect,
         * execution will resume after the operation completes.
         */
    } else {
        debug(33, 1) ("clientKeepaliveNextRequest: FD %d Sending next\n",
            conn->fd);
        assert(entry);
        if (0 == storeClientCopyPending(http->sc, entry, http)) {
            if (EBIT_TEST(entry->flags, ENTRY_ABORTED))
                debug(33, 0) ("clientKeepaliveNextRequest: ENTRY_ABORTED\n");
            storeClientCopy(http->sc, entry,
                http->out.offset,
                http->out.offset,
                CLIENT_SOCK_SZ,
                memAllocate(MEM_CLIENT_SOCK_BUF),
                clientSendMoreData,
                http);
        }
    }
}

static void
clientWriteComplete(int fd, char *bufnotused, size_t size, int errflag, void *data)
{
    clientHttpRequest *http = data;
    StoreEntry *entry = http->entry;
    int done;
    http->out.size += size;
    debug(33, 5) ("clientWriteComplete: FD %d, sz %d, err %d, off %d, len %d\n",
        fd, size, errflag, (int) http->out.offset, entry ? objectLen(entry) : 0);
    if (size > 0) {
        kb_incr(&statCounter.client_http.kbytes_out, size);
        if (isTcpHit(http->log_type))
            kb_incr(&statCounter.client_http.hit_kbytes_out, size);
    }
    if (errflag) {
        /*
         * just close the socket, httpRequestFree will abort if needed
         */
        comm_close(fd);
    } else if (NULL == entry) {
        comm_close(fd);         /* yuk */
    } else if (EBIT_TEST(entry->flags, ENTRY_ABORTED)) {
        comm_close(fd);
    } else if ((done = clientCheckTransferDone(http)) != 0 || size == 0) {
        debug(33, 5) ("clientWriteComplete: FD %d transfer is DONE\n", fd);
        /* We're finished case */
        if (httpReplyBodySize(http->request->method, entry->mem_obj->reply) < 0) {
            debug(33, 5) ("clientWriteComplete: closing, content_length < 0\n");
            comm_close(fd);
        } else if (!done) {
            debug(33, 5) ("clientWriteComplete: closing, !done\n");
            comm_close(fd);
        } else if (clientGotNotEnough(http)) {
            debug(33, 5) ("clientWriteComplete: client didn't get all it expected\n");
            comm_close(fd);
        } else if (http->request->flags.proxy_keepalive) {
            debug(33, 5) ("clientWriteComplete: FD %d Keeping Alive\n", fd);
            clientKeepaliveNextRequest(http);
        } else {
            comm_close(fd);
        }
    } else if (clientReplyBodyTooLarge((int) http->out.offset)) {
        comm_close(fd);
    } else {
        /* More data will be coming from primary server; register with 
         * storage manager. */
        if (EBIT_TEST(entry->flags, ENTRY_ABORTED))
            debug(33, 0) ("clientWriteComplete 2: ENTRY_ABORTED\n");
        storeClientCopy(http->sc, entry,
            http->out.offset,
            http->out.offset,
            CLIENT_SOCK_SZ,
            memAllocate(MEM_CLIENT_SOCK_BUF),
            clientSendMoreData,
            http);
    }
}

/*
 * client issued a request with an only-if-cached cache-control directive;
 * we did not find a cached object that can be returned without
 *     contacting other servers;
 * respond with a 504 (Gateway Timeout) as suggested in [RFC 2068]
 */
static void
clientProcessOnlyIfCachedMiss(clientHttpRequest * http)
{
    char *url = http->uri;
    request_t *r = http->request;
    ErrorState *err = NULL;
    debug(33, 4) ("clientProcessOnlyIfCachedMiss: '%s %s'\n",
        RequestMethodStr[r->method], url);
    http->al.http.code = HTTP_GATEWAY_TIMEOUT;
    err = errorCon(ERR_ONLY_IF_CACHED_MISS, HTTP_GATEWAY_TIMEOUT);
    err->request = requestLink(r);
    err->src_addr = http->conn->peer.sin_addr;
    if (http->entry) {
        storeUnregister(http->sc, http->entry, http);
        http->sc = NULL;
        storeUnlockObject(http->entry);
    }
    http->entry = clientCreateStoreEntry(http, r->method, null_request_flags);
    errorAppendEntry(http->entry, err);
}

/* 
 * Return true if we should force a cache miss on this range request.
 * entry must be non-NULL.
 */
static int
clientCheckRangeForceMiss(StoreEntry * entry, HttpHdrRange * range)
{
    /*
     * If the range_offset_limit is NOT in effect, there
     * is no reason to force a miss.
     */
    if (0 == httpHdrRangeOffsetLimit(range))
        return 0;
    /*
     * Here, we know it's possibly a hit.  If we already have the
     * whole object cached, we won't force a miss.
     */
    if (STORE_OK == entry->store_status)
        return 0;               /* we have the whole object */
    /*
     * Now we have a hit on a PENDING object.  We need to see
     * if the part we want is already cached.  If so, we don't
     * force a miss.
     */
    assert(NULL != entry->mem_obj);
    if (httpHdrRangeFirstOffset(range) <= entry->mem_obj->inmem_hi)
        return 0;
    /*
     * Even though we have a PENDING copy of the object, we
     * don't want to wait to reach the first range offset,
     * so we force a miss for a new range request to the
     * origin.
     */
    return 1;
}

static log_type
clientProcessRequest2(clientHttpRequest * http)
{
    request_t *r = http->request;
    StoreEntry *e;
    e = http->entry = storeGetPublic(http->uri, r->method);
    if (r->method == METHOD_HEAD && e == NULL) {
        /* We can generate a HEAD reply from a cached GET object */
        e = http->entry = storeGetPublic(http->uri, METHOD_GET);
    }
    /* Release negatively cached IP-cache entries on reload */
    if (r->flags.nocache)
        ipcacheInvalidate(r->host);
#if HTTP_VIOLATIONS
    else if (r->flags.nocache_hack)
        ipcacheInvalidate(r->host);
#endif
#if USE_CACHE_DIGESTS
    http->lookup_type = e ? "HIT" : "MISS";
#endif
    if (NULL == e) {
        /* this object isn't in the cache */
        debug(33, 3) ("clientProcessRequest2: storeGet() MISS\n");
        return LOG_TCP_MISS;
    }
    if (Config.onoff.offline) {
        debug(33, 3) ("clientProcessRequest2: offline HIT\n");
        http->entry = e;
        return LOG_TCP_HIT;
    }
    if (http->redirect.status) {
        /* force this to be a miss */
        http->entry = NULL;
        return LOG_TCP_MISS;
    }
    if (!storeEntryValidToSend(e)) {
        debug(33, 3) ("clientProcessRequest2: !storeEntryValidToSend MISS\n");
        http->entry = NULL;
        return LOG_TCP_MISS;
    }
    if (EBIT_TEST(e->flags, ENTRY_SPECIAL)) {
        /* Special entries are always hits, no matter what the client says */
        debug(33, 3) ("clientProcessRequest2: ENTRY_SPECIAL HIT\n");
        http->entry = e;
        return LOG_TCP_HIT;
    }
#if HTTP_VIOLATIONS
    if (e->store_status == STORE_PENDING) {
        if (r->flags.nocache || r->flags.nocache_hack) {
            debug(33, 3) ("Clearing no-cache for STORE_PENDING request\n\t%s\n",
                storeUrl(e));
            r->flags.nocache = 0;
            r->flags.nocache_hack = 0;
        }
    }
#endif
    if (r->flags.nocache) {
        debug(33, 3) ("clientProcessRequest2: no-cache REFRESH MISS\n");
        http->entry = NULL;
        ipcacheInvalidate(r->host);
        return LOG_TCP_CLIENT_REFRESH_MISS;
    }
    if (NULL == r->range) {
        (void) 0;
    } else if (httpHdrRangeWillBeComplex(r->range)) {
        /*
         * Some clients break if we return "200 OK" for a Range
         * request.  We would have to return "200 OK" for a _complex_
         * Range request that is also a HIT. Thus, let's prevent HITs
         * on complex Range requests
         */
        debug(33, 3) ("clientProcessRequest2: complex range MISS\n");
        http->entry = NULL;
        return LOG_TCP_MISS;
    } else if (clientCheckRangeForceMiss(e, r->range)) {
        debug(33, 3) ("clientProcessRequest2: forcing miss due to range_offset_limit\n");
        http->entry = NULL;
        return LOG_TCP_MISS;
    }
    debug(33, 3) ("clientProcessRequest2: default HIT\n");
    http->entry = e;
    return LOG_TCP_HIT;
}

static void
clientProcessRequest(clientHttpRequest * http)
{
    char *url = http->uri;
    request_t *r = http->request;
    int fd = http->conn->fd;
    HttpReply *rep;
    http_version_t version;
    debug(33, 4) ("clientProcessRequest: %s '%s'\n",
        RequestMethodStr[r->method],
        url);
    if (r->method == METHOD_CONNECT) {
        http->log_type = LOG_TCP_MISS;
        sslStart(fd, url, r, &http->out.size, &http->al.http.code);
        return;
    } else if (r->method == METHOD_PURGE) {
        clientPurgeRequest(http);
        return;
    } else if (r->method == METHOD_TRACE) {
        if (r->max_forwards == 0) {
            http->entry = clientCreateStoreEntry(http, r->method, null_request_flags);
            storeReleaseRequest(http->entry);
            storeBuffer(http->entry);
            rep = httpReplyCreate();
            httpBuildVersion(&version, 1, 0);
            httpReplySetHeaders(rep, version, HTTP_OK, NULL, "text/plain",
                httpRequestPrefixLen(r), 0, squid_curtime);
            httpReplySwapOut(rep, http->entry);
            httpReplyDestroy(rep);
            httpRequestSwapOut(r, http->entry);
            storeComplete(http->entry);
            return;
        }
        /* yes, continue */
        http->log_type = LOG_TCP_MISS;
    } else if (r->content_length >= 0) {
        /*
         * Need to initialize pump even if content-length: 0
         */
        http->log_type = LOG_TCP_MISS;
        /* XXX oof, POST can be cached! */
        pumpInit(fd, r, http->uri);
    } else {
        http->log_type = clientProcessRequest2(http);
    }
    debug(33, 4) ("clientProcessRequest: %s for '%s'\n",
        log_tags[http->log_type],
        http->uri);
    http->out.offset = 0;
    if (NULL != http->entry) {
        storeLockObject(http->entry);
        storeCreateMemObject(http->entry, http->uri, http->log_uri);
        http->entry->mem_obj->method = r->method;
        http->sc = storeClientListAdd(http->entry, http);
#if DELAY_POOLS
        delaySetStoreClient(http->sc, delayClient(r));
#endif
        storeClientCopy(http->sc, http->entry,
            http->out.offset,
            http->out.offset,
            CLIENT_SOCK_SZ,
            memAllocate(MEM_CLIENT_SOCK_BUF),
            clientCacheHit,
            http);
    } else {
        /* MISS CASE, http->log_type is already set! */
        clientProcessMiss(http);
    }
}

/*
 * Prepare to fetch the object as it's a cache miss of some kind.
 */
static void
clientProcessMiss(clientHttpRequest * http)
{
    char *url = http->uri;
    request_t *r = http->request;
    ErrorState *err = NULL;
    debug(33, 4) ("clientProcessMiss: '%s %s'\n",
        RequestMethodStr[r->method], url);
    /*
     * We might have a left-over StoreEntry from a failed cache hit
     * or IMS request.
     */
    if (http->entry) {
        if (EBIT_TEST(http->entry->flags, ENTRY_SPECIAL)) {
            debug(33, 0) ("clientProcessMiss: miss on a special object (%s).\n", url);
            debug(33, 0) ("\tlog_type = %s\n", log_tags[http->log_type]);
            storeEntryDump(http->entry, 1);
        }
        storeUnregister(http->sc, http->entry, http);
        http->sc = NULL;
        storeUnlockObject(http->entry);
        http->entry = NULL;
    }
    if (clientOnlyIfCached(http)) {
        clientProcessOnlyIfCachedMiss(http);
        return;
    }
    /*
     * Deny loops when running in accelerator/transproxy mode.
     */
    if (http->flags.accel && r->flags.loopdetect) {
        http->al.http.code = HTTP_FORBIDDEN;
        err = errorCon(ERR_ACCESS_DENIED, HTTP_FORBIDDEN);
        err->request = requestLink(r);
        err->src_addr = http->conn->peer.sin_addr;
        http->entry = clientCreateStoreEntry(http, r->method, null_request_flags);
        errorAppendEntry(http->entry, err);
        return;
    }
    assert(http->out.offset == 0);
    http->entry = clientCreateStoreEntry(http, r->method, r->flags);
    if (http->redirect.status) {
        HttpReply *rep = httpReplyCreate();
#if LOG_TCP_REDIRECTS
        http->log_type = LOG_TCP_REDIRECT;
#endif
        storeReleaseRequest(http->entry);
        httpRedirectReply(rep, http->redirect.status, http->redirect.location);
        httpReplySwapOut(rep, http->entry);
        httpReplyDestroy(rep);
        storeComplete(http->entry);
        return;
    }
    if (http->flags.internal)
        r->protocol = PROTO_INTERNAL;
    fwdStart(http->conn->fd, http->entry, r);
}

static clientHttpRequest *
parseHttpRequestAbort(ConnStateData * conn, const char *uri)
{
    clientHttpRequest *http = memAllocate(MEM_CLIENTHTTPREQUEST);
    cbdataAdd(http, memFree, MEM_CLIENTHTTPREQUEST);
    http->conn = conn;
    http->start = current_time;
    http->req_sz = conn->in.offset;
    http->uri = xstrdup(uri);
    http->log_uri = xstrndup(uri, MAX_URL);
    http->range_iter.boundary = StringNull;
    dlinkAdd(http, &http->active, &ClientActiveRequests);
    return http;
}

/*
 *  parseHttpRequest()
 * 
 *  Returns
 *   NULL on error or incomplete request
 *    a clientHttpRequest structure on success
 */
static clientHttpRequest *
parseHttpRequest(ConnStateData * conn, method_t * method_p, int *status,
    char **prefix_p, size_t * req_line_sz_p)
{
    char *inbuf = NULL;
    char *mstr = NULL;
    char *url = NULL;
    char *req_hdr = NULL;
    http_version_t http_ver;
    char *token = NULL;
    char *t = NULL;
    char *end;
    size_t header_sz;           /* size of headers, not including first line */
    size_t prefix_sz;           /* size of whole request (req-line + headers) */
    size_t url_sz;
    size_t req_sz;
    method_t method;
    clientHttpRequest *http = NULL;
#if IPF_TRANSPARENT
    struct natlookup natLookup;
    static int natfd = -1;
    static int siocgnatl_cmd = SIOCGNATL & 0xff;
    int x;
#endif
#if LINUX_NETFILTER
    size_t sock_sz = sizeof(conn->me);
#endif

    if ((req_sz = headersEnd(conn->in.buf, conn->in.offset)) == 0) {
        debug(33, 5) ("Incomplete request, waiting for end of headers\n");
        *status = 0;
        *prefix_p = NULL;
        *method_p = METHOD_NONE;
        return NULL;
    }
    assert(req_sz <= conn->in.offset);
    /* Use memcpy, not strdup! */
    inbuf = xmalloc(req_sz + 1);
    xmemcpy(inbuf, conn->in.buf, req_sz);
    *(inbuf + req_sz) = '\0';

    /* pre-set these values to make aborting simpler */
    *prefix_p = inbuf;
    *method_p = METHOD_NONE;
    *status = -1;

    /* Barf on NULL characters in the headers */
    if (strlen(inbuf) != req_sz) {
        debug(33, 1) ("parseHttpRequest: Requestheader contains NULL characters\n");
        return parseHttpRequestAbort(conn, "error:invalid-request");
    }
    /* Look for request method */
    if ((mstr = strtok(inbuf, "\t ")) == NULL) {
        debug(33, 1) ("parseHttpRequest: Can't get request method\n");
        return parseHttpRequestAbort(conn, "error:invalid-request-method");
    }
    method = urlParseMethod(mstr);
    if (method == METHOD_NONE) {
        debug(33, 1) ("parseHttpRequest: Unsupported method '%s'\n", mstr);
        return parseHttpRequestAbort(conn, "error:unsupported-request-method");
    }
    debug(33, 5) ("parseHttpRequest: Method is '%s'\n", mstr);
    *method_p = method;

    /* look for URL+HTTP/x.x */
    if ((url = strtok(NULL, "\n")) == NULL) {
        debug(33, 1) ("parseHttpRequest: Missing URL\n");
        return parseHttpRequestAbort(conn, "error:missing-url");
    }
    while (xisspace(*url))
        url++;
    t = url + strlen(url);
    assert(*t == '\0');
    token = NULL;
    while (t > url) {
        t--;
        if (xisspace(*t) && !strncmp(t + 1, "HTTP/", 5)) {
            token = t + 1;
            break;
        }
    }
    while (t > url && xisspace(*t))
        *(t--) = '\0';
    debug(33, 5) ("parseHttpRequest: URI is '%s'\n", url);
    if (token == NULL) {
        debug(33, 3) ("parseHttpRequest: Missing HTTP identifier\n");
#if RELAXED_HTTP_PARSER
        httpBuildVersion(&http_ver, 0, 9);      /* wild guess */
#else
        return parseHttpRequestAbort(conn, "error:missing-http-ident");
#endif
    } else {
        if (sscanf(token + 5, "%d.%d", &http_ver.major, &http_ver.minor) != 2) {
            debug(33, 3) ("parseHttpRequest: Invalid HTTP identifier.\n");
            return parseHttpRequestAbort(conn, "error: invalid HTTP-ident");
        }
        debug(33, 6) ("parseHttpRequest: Client HTTP version %d.%d.\n", http_ver.major, http_ver.minor);
    }

    /*
     * Process headers after request line
     */
    req_hdr = strtok(NULL, null_string);
    header_sz = req_sz - (req_hdr - inbuf);
    if (0 == header_sz) {
        debug(33, 3) ("parseHttpRequest: header_sz == 0\n");
        *status = 0;
        return NULL;
    }
    assert(header_sz > 0);
    debug(33, 3) ("parseHttpRequest: req_hdr = {%s}\n", req_hdr);
    end = req_hdr + header_sz;
    debug(33, 3) ("parseHttpRequest: end = {%s}\n", end);

    prefix_sz = end - inbuf;
    *req_line_sz_p = req_hdr - inbuf;
    debug(33, 3) ("parseHttpRequest: prefix_sz = %d, req_line_sz = %d\n",
        (int) prefix_sz, (int) *req_line_sz_p);
    assert(prefix_sz <= conn->in.offset);

    /* Ok, all headers are received */
    http = memAllocate(MEM_CLIENTHTTPREQUEST);
    cbdataAdd(http, memFree, MEM_CLIENTHTTPREQUEST);
    http->http_ver = http_ver;
    http->conn = conn;
    http->start = current_time;
    http->req_sz = prefix_sz;
    http->range_iter.boundary = StringNull;
    *prefix_p = xmalloc(prefix_sz + 1);
    xmemcpy(*prefix_p, conn->in.buf, prefix_sz);
    *(*prefix_p + prefix_sz) = '\0';
    dlinkAdd(http, &http->active, &ClientActiveRequests);

    debug(33, 5) ("parseHttpRequest: Request Header is\n%s\n", (*prefix_p) + *req_line_sz_p);
    if ((t = strchr(url, '#'))) /* remove HTML anchors */
        *t = '\0';

    /* handle internal objects */
    if (internalCheck(url)) {
        /* prepend our name & port */
        http->uri = xstrdup(internalLocalUri(NULL, url));
        http->flags.internal = 1;
        http->flags.accel = 1;
    }
    /* see if we running in Config2.Accel.on, if so got to convert it to URL */
    else if (Config2.Accel.on && *url == '/') {
        /* prepend the accel prefix */
        if (opt_accel_uses_host && (t = mime_get_header(req_hdr, "Host"))) {
            int vport = (int) Config.Accel.port;
            char *q;
            /* If a Host: header was specified, use it to build the URL 
             * instead of the one in the Config file. */
            /*
             * XXX Use of the Host: header here opens a potential
             * security hole.  There are no checks that the Host: value
             * corresponds to one of your servers.  It might, for example,
             * refer to www.playboy.com.  The 'dst' and/or 'dst_domain' ACL 
             * types should be used to prevent httpd-accelerators 
             * handling requests for non-local servers */
            strtok(t, " /;@");
            if ((q = strchr(t, ':'))) {
                *q++ = '\0';
                vport = atoi(q);
            }
            url_sz = strlen(url) + 32 + Config.appendDomainLen +
                strlen(t);
            http->uri = xcalloc(url_sz, 1);
            snprintf(http->uri, url_sz, "http://%s:%d%s",
                t, vport, url);
        } else if (vhost_mode) {
            int vport;
            /* Put the local socket IP address as the hostname */
            url_sz = strlen(url) + 32 + Config.appendDomainLen;
            http->uri = xcalloc(url_sz, 1);
            if (vport_mode)
                vport = (int) ntohs(http->conn->me.sin_port);
            else
                vport = (int) Config.Accel.port;
#if IPF_TRANSPARENT
            natLookup.nl_inport = http->conn->me.sin_port;
            natLookup.nl_outport = http->conn->peer.sin_port;
            natLookup.nl_inip = http->conn->me.sin_addr;
            natLookup.nl_outip = http->conn->peer.sin_addr;
            natLookup.nl_flags = IPN_TCP;
            if (natfd < 0)
                natfd = open(IPL_NAT, O_RDONLY, 0);
            if (natfd < 0) {
                debug(50, 1) ("parseHttpRequest: NAT open failed: %s\n",
                    xstrerror());
                return parseHttpRequestAbort(conn, "error:nat-open-failed");
            }
            /*
             * IP-Filter changed the type for SIOCGNATL between
             * 3.3 and 3.4.  It also changed the cmd value for
             * SIOCGNATL, so at least we can detect it.  We could
             * put something in configure and use ifdefs here, but
             * this seems simpler.
             */
            if (63 == siocgnatl_cmd) {
                struct natlookup *nlp = &natLookup;
                x = ioctl(natfd, SIOCGNATL, &nlp);
            } else {
                x = ioctl(natfd, SIOCGNATL, &natLookup);
            }
            if (x < 0) {
                if (errno != ESRCH) {
                    debug(50, 1) ("parseHttpRequest: NAT lookup failed: ioctl(SIOCGNATL)\n");
                    close(natfd);
                    natfd = -1;
                    return parseHttpRequestAbort(conn, "error:nat-lookup-failed");
                } else
                    snprintf(http->uri, url_sz, "http://%s:%d%s",
                        inet_ntoa(http->conn->me.sin_addr),
                        vport, url);
            } else
                snprintf(http->uri, url_sz, "http://%s:%d%s",
                    inet_ntoa(natLookup.nl_realip),
                    vport, url);
#else
#if LINUX_NETFILTER
          /* If the call fails the address structure will be unchanged */
          getsockopt(conn->fd, SOL_IP, SO_ORIGINAL_DST, &conn->me, &sock_sz );
            debug(33, 5) ("parseHttpRequest: addr = %s", inet_ntoa(conn->me.sin_addr) );
#endif
            snprintf(http->uri, url_sz, "http://%s:%d%s",
                inet_ntoa(http->conn->me.sin_addr),
                vport, url);
#endif
            debug(33, 5) ("VHOST REWRITE: '%s'\n", http->uri);
        } else {
            url_sz = strlen(Config2.Accel.prefix) + strlen(url) +
                Config.appendDomainLen + 1;
            http->uri = xcalloc(url_sz, 1);
            snprintf(http->uri, url_sz, "%s%s", Config2.Accel.prefix, url);
        }
        http->flags.accel = 1;
    } else {
        /* URL may be rewritten later, so make extra room */
        url_sz = strlen(url) + Config.appendDomainLen + 5;
        http->uri = xcalloc(url_sz, 1);
        strcpy(http->uri, url);
        http->flags.accel = 0;
    }
    if (!stringHasCntl(http->uri))
        http->log_uri = xstrndup(http->uri, MAX_URL);
    else
        http->log_uri = xstrndup(rfc1738_escape_unescaped(http->uri), MAX_URL);
    debug(33, 5) ("parseHttpRequest: Complete request received\n");
    xfree(inbuf);
    *status = 1;
    return http;
}

static int
clientReadDefer(int fdnotused, void *data)
{
    ConnStateData *conn = data;
    return conn->defer.until > squid_curtime;
}

static void
clientReadRequest(int fd, void *data)
{
    ConnStateData *conn = data;
    int parser_return_code = 0;
    int k;
    request_t *request = NULL;
    int size;
    void *p;
    method_t method;
    clientHttpRequest *http = NULL;
    clientHttpRequest **H = NULL;
    char *prefix = NULL;
    ErrorState *err = NULL;
    fde *F = &fd_table[fd];
    int len = conn->in.size - conn->in.offset - 1;
    debug(33, 4) ("clientReadRequest: FD %d: reading request...\n", fd);
    statCounter.syscalls.sock.reads++;
    size = read(fd, conn->in.buf + conn->in.offset, len);
    if (size > 0) {
        fd_bytes(fd, size, FD_READ);
        kb_incr(&statCounter.client_http.kbytes_in, size);
    }
    /*
     * Don't reset the timeout value here.  The timeout value will be
     * set to Config.Timeout.request by httpAccept() and
     * clientWriteComplete(), and should apply to the request as a
     * whole, not individual read() calls.  Plus, it breaks our
     * lame half-close detection
     */
    commSetSelect(fd, COMM_SELECT_READ, clientReadRequest, conn, 0);
    if (size == 0) {
        if (conn->chr == NULL) {
            /* no current or pending requests */
            comm_close(fd);
            return;
        } else if (!Config.onoff.half_closed_clients) {
            /* admin doesn't want to support half-closed client sockets */
            comm_close(fd);
            return;
        }
        /* It might be half-closed, we can't tell */
        debug(33, 5) ("clientReadRequest: FD %d closed?\n", fd);
        F->flags.socket_eof = 1;
        conn->defer.until = squid_curtime + 1;
        conn->defer.n++;
        fd_note(fd, "half-closed");
        return;
    } else if (size < 0) {
        if (!ignoreErrno(errno)) {
            debug(50, 2) ("clientReadRequest: FD %d: %s\n", fd, xstrerror());
            comm_close(fd);
            return;
        } else if (conn->in.offset == 0) {
            debug(50, 2) ("clientReadRequest: FD %d: no data to process (%s)\n", fd, xstrerror());
            return;
        }
        /* Continue to process previously read data */
        size = 0;
    }
    conn->in.offset += size;
    /* Skip leading (and trailing) whitespace */
    while (conn->in.offset > 0) {
        int nrequests;
        size_t req_line_sz;
        while (conn->in.offset > 0 && xisspace(conn->in.buf[0])) {
            xmemmove(conn->in.buf, conn->in.buf + 1, conn->in.offset - 1);
            conn->in.offset--;
        }
        conn->in.buf[conn->in.offset] = '\0';   /* Terminate the string */
        if (conn->in.offset == 0)
            break;
        /* Limit the number of concurrent requests to 2 */
        for (H = &conn->chr, nrequests = 0; *H; H = &(*H)->next, nrequests++);
        if (nrequests >= 2) {
            debug(33, 3) ("clientReadRequest: FD %d max concurrent requests reached\n", fd);
            debug(33, 5) ("clientReadRequest: FD %d defering new request until one is done\n", fd);
            conn->defer.until = squid_curtime + 100;    /* Reset when a request is complete */
            break;
        }
        /* Process request */
        http = parseHttpRequest(conn,
            &method,
            &parser_return_code,
            &prefix,
            &req_line_sz);
        if (!http)
            safe_free(prefix);
        if (http) {
            assert(http->req_sz > 0);
            conn->in.offset -= http->req_sz;
            assert(conn->in.offset >= 0);
            debug(33, 5) ("conn->in.offset = %d\n", (int) conn->in.offset);
            /*
             * If we read past the end of this request, move the remaining
             * data to the beginning
             */
            if (conn->in.offset > 0)
                xmemmove(conn->in.buf, conn->in.buf + http->req_sz, conn->in.offset);
            /* add to the client request queue */
            for (H = &conn->chr; *H; H = &(*H)->next);
            *H = http;
            conn->nrequests++;
            /*
             * I wanted to lock 'http' here since its callback data for 
             * clientLifetimeTimeout(), but there's no logical place to
             * cbdataUnlock if the timeout never happens.  Maybe its safe
             * enough to assume that if the FD is open, and the timeout
             * triggers, that 'http' is valid.
             */
            commSetTimeout(fd, Config.Timeout.lifetime, clientLifetimeTimeout, http);
            if (parser_return_code < 0) {
                debug(33, 1) ("clientReadRequest: FD %d Invalid Request\n", fd);
                err = errorCon(ERR_INVALID_REQ, HTTP_BAD_REQUEST);
                err->request_hdrs = xstrdup(conn->in.buf);
                http->entry = clientCreateStoreEntry(http, method, null_request_flags);
                errorAppendEntry(http->entry, err);
                safe_free(prefix);
                break;
            }
            if ((request = urlParse(method, http->uri)) == NULL) {
                debug(33, 5) ("Invalid URL: %s\n", http->uri);
                err = errorCon(ERR_INVALID_URL, HTTP_BAD_REQUEST);
                err->src_addr = conn->peer.sin_addr;
                err->url = xstrdup(http->uri);
                http->al.http.code = err->http_status;
                http->entry = clientCreateStoreEntry(http, method, null_request_flags);
                errorAppendEntry(http->entry, err);
                safe_free(prefix);
                break;
            } else {
                /* compile headers */
                /* we should skip request line! */
                if (!httpRequestParseHeader(request, prefix + req_line_sz))
                    debug(33, 1) ("Failed to parse request headers: %s\n%s\n",
                        http->uri, prefix);
                /* continue anyway? */
            }
            request->flags.accelerated = http->flags.accel;
            if (!http->flags.internal) {
                if (internalCheck(strBuf(request->urlpath))) {
                    if (internalHostnameIs(request->host) &&
                        request->port == ntohs(Config.Sockaddr.http->s.sin_port)) {
                        http->flags.internal = 1;
                    } else if (internalStaticCheck(strBuf(request->urlpath))) {
                        xstrncpy(request->host, internalHostname(), SQUIDHOSTNAMELEN);
                        request->port = ntohs(Config.Sockaddr.http->s.sin_port);
                        http->flags.internal = 1;
                    }
                }
            }
            /*
             * cache the Content-length value in request_t.
             */
            request->content_length = httpHeaderGetInt(&request->header,
                HDR_CONTENT_LENGTH);
            request->flags.internal = http->flags.internal;
            safe_free(prefix);
            safe_free(http->log_uri);
            http->log_uri = xstrdup(urlCanonicalClean(request));
            request->client_addr = conn->peer.sin_addr;
            request->my_addr = conn->me.sin_addr;
            request->my_port = ntohs(conn->me.sin_port);
            request->http_ver = http->http_ver;
            if (!urlCheckRequest(request)) {
                err = errorCon(ERR_UNSUP_REQ, HTTP_NOT_IMPLEMENTED);
                err->src_addr = conn->peer.sin_addr;
                err->request = requestLink(request);
                request->flags.proxy_keepalive = 0;
                http->al.http.code = err->http_status;
                http->entry = clientCreateStoreEntry(http, request->method, null_request_flags);
                errorAppendEntry(http->entry, err);
                break;
            }
            if (0 == clientCheckContentLength(request)) {
                err = errorCon(ERR_INVALID_REQ, HTTP_LENGTH_REQUIRED);
                err->src_addr = conn->peer.sin_addr;
                err->request = requestLink(request);
                http->al.http.code = err->http_status;
                http->entry = clientCreateStoreEntry(http, request->method, null_request_flags);
                errorAppendEntry(http->entry, err);
                break;
            }
            http->request = requestLink(request);
            /*
             * We need to set the keepalive flag before doing some
             * hacks for POST/PUT requests below.  Maybe we could
             * set keepalive flag even earlier.
             */
            clientSetKeepaliveFlag(http);
            /*
             * break here if the request has a content-length
             * because there is a reqeust body following and we
             * don't want to parse it as though it was new request.
             */
            if (request->content_length >= 0) {
                int copy_len = XMIN(conn->in.offset, request->content_length);
                if (copy_len > 0) {
                    assert(conn->in.offset >= copy_len);
                    request->body_sz = copy_len;
                    request->body = xmalloc(request->body_sz);
                    xmemcpy(request->body, conn->in.buf, request->body_sz);
                    conn->in.offset -= copy_len;
                    if (conn->in.offset)
                        xmemmove(conn->in.buf, conn->in.buf + copy_len, conn->in.offset);
                }
                /*
                 * if we didn't get the full body now, then more will
                 * be arriving on the client socket.  Lets cancel
                 * the read handler until this request gets forwarded.
                 */
                if (request->body_sz < request->content_length)
                    commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
                if (request->content_length < 0)
                    (void) 0;
                else if (clientRequestBodyTooLarge(request->content_length)) {
                    err = errorCon(ERR_TOO_BIG, HTTP_REQUEST_ENTITY_TOO_LARGE);
                    err->request = requestLink(request);
                    http->entry = clientCreateStoreEntry(http,
                        METHOD_NONE, null_request_flags);
                    errorAppendEntry(http->entry, err);
                    break;
                }
            }
            clientAccessCheck(http);
            continue;           /* while offset > 0 */
        } else if (parser_return_code == 0) {
            /*
             *    Partial request received; reschedule until parseHttpRequest()
             *    is happy with the input
             */
            k = conn->in.size - 1 - conn->in.offset;
            if (k == 0) {
                if (conn->in.offset >= Config.maxRequestHeaderSize) {
                    /* The request is too large to handle */
                    debug(33, 1) ("Request header is too large (%d bytes)\n",
                        (int) conn->in.offset);
                    debug(33, 1) ("Config 'request_header_max_size'= %d bytes.\n",
                        Config.maxRequestHeaderSize);
                    err = errorCon(ERR_TOO_BIG, HTTP_REQUEST_ENTITY_TOO_LARGE);
                    http = parseHttpRequestAbort(conn, "error:request-too-large");
                    /* add to the client request queue */
                    for (H = &conn->chr; *H; H = &(*H)->next);
                    *H = http;
                    http->entry = clientCreateStoreEntry(http, METHOD_NONE, null_request_flags);
                    errorAppendEntry(http->entry, err);
                    return;
                }
                /* Grow the request memory area to accomodate for a large request */
                conn->in.size += CLIENT_REQ_BUF_SZ;
                if (conn->in.size == 2 * CLIENT_REQ_BUF_SZ) {
                    p = conn->in.buf;   /* get rid of fixed size Pooled buffer */
                    conn->in.buf = xcalloc(2, CLIENT_REQ_BUF_SZ);
                    xmemcpy(conn->in.buf, p, CLIENT_REQ_BUF_SZ);
                    memFree(p, MEM_CLIENT_REQ_BUF);
                } else
                    conn->in.buf = xrealloc(conn->in.buf, conn->in.size);
                /* XXX account conn->in.buf */
                debug(33, 3) ("Handling a large request, offset=%d inbufsize=%d\n",
                    (int) conn->in.offset, conn->in.size);
                k = conn->in.size - 1 - conn->in.offset;
            }
            break;
        }
    }
}

/* general lifetime handler for HTTP requests */
static void
requestTimeout(int fd, void *data)
{
#if THIS_CONFUSES_PERSISTENT_CONNECTION_AWARE_BROWSERS_AND_USERS
    ConnStateData *conn = data;
    ErrorState *err;
    debug(33, 3) ("requestTimeout: FD %d: lifetime is expired.\n", fd);
    if (fd_table[fd].rwstate) {
        /*
         * Some data has been sent to the client, just close the FD
         */
        comm_close(fd);
    } else if (conn->nrequests) {
        /*
         * assume its a persistent connection; just close it
         */
        comm_close(fd);
    } else {
        /*
         * Generate an error
         */
        err = errorCon(ERR_LIFETIME_EXP, HTTP_REQUEST_TIMEOUT);
        err->url = xstrdup("N/A");
        /*
         * Normally we shouldn't call errorSend() in client_side.c, but
         * it should be okay in this case.  Presumably if we get here
         * this is the first request for the connection, and no data
         * has been written yet
         */
        assert(conn->chr == NULL);
        errorSend(fd, err);
        /*
         * if we don't close() here, we still need a timeout handler!
         */
        commSetTimeout(fd, 30, requestTimeout, conn);
        /*
         * Aha, but we don't want a read handler!
         */
        commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
    }
#else
    /*
     * Just close the connection to not confuse browsers
     * using persistent connections. Some browsers opens
     * an connection and then does not use it until much
     * later (presumeably because the request triggering
     * the open has already been completed on another
     * connection)
     */
    debug(33, 3) ("requestTimeout: FD %d: lifetime is expired.\n", fd);
    comm_close(fd);
#endif
}

static void
clientLifetimeTimeout(int fd, void *data)
{
    clientHttpRequest *http = data;
    ConnStateData *conn = http->conn;
    debug(33, 1) ("WARNING: Closing client %s connection due to lifetime timeout\n",
        inet_ntoa(conn->peer.sin_addr));
    debug(33, 1) ("\t%s\n", http->uri);
    comm_close(fd);
}

static int
httpAcceptDefer(int fdunused, void *dataunused)
{
    static time_t last_warn = 0;
    if (fdNFree() >= RESERVED_FD)
        return 0;
    if (last_warn + 15 < squid_curtime) {
        debug(33, 0) ("WARNING! Your cache is running out of filedescriptors\n");
        last_warn = squid_curtime;
    }
    return 1;
}

/* Handle a new connection on HTTP socket. */
void
httpAccept(int sock, void *data)
{
    int *N = data;
    int fd = -1;
    ConnStateData *connState = NULL;
    struct sockaddr_in peer;
    struct sockaddr_in me;
    int max = INCOMING_HTTP_MAX;
#if USE_IDENT
    static aclCheck_t identChecklist;
#endif
    commSetSelect(sock, COMM_SELECT_READ, httpAccept, NULL, 0);
    while (max-- && !httpAcceptDefer(sock, NULL)) {
        memset(&peer, '\0', sizeof(struct sockaddr_in));
        memset(&me, '\0', sizeof(struct sockaddr_in));
        if ((fd = comm_accept(sock, &peer, &me)) < 0) {
            if (!ignoreErrno(errno))
                debug(50, 1) ("httpAccept: FD %d: accept failure: %s\n",
                    sock, xstrerror());
            break;
        }
        debug(33, 4) ("httpAccept: FD %d: accepted\n", fd);
        connState = memAllocate(MEM_CONNSTATEDATA);
        cbdataAdd(connState, memFree, MEM_CONNSTATEDATA);
        connState->peer = peer;
        connState->log_addr = peer.sin_addr;
        connState->log_addr.s_addr &= Config.Addrs.client_netmask.s_addr;
        connState->me = me;
        connState->fd = fd;
        connState->in.size = CLIENT_REQ_BUF_SZ;
        connState->in.buf = memAllocate(MEM_CLIENT_REQ_BUF);
        /* XXX account connState->in.buf */
        comm_add_close_handler(fd, connStateFree, connState);
        if (Config.onoff.log_fqdn)
            fqdncache_gethostbyaddr(peer.sin_addr, FQDN_LOOKUP_IF_MISS);
        commSetTimeout(fd, Config.Timeout.request, requestTimeout, connState);
#if USE_IDENT
        identChecklist.src_addr = peer.sin_addr;
        identChecklist.my_addr = me.sin_addr;
        identChecklist.my_port = ntohs(me.sin_port);
        if (aclCheckFast(Config.accessList.identLookup, &identChecklist))
            identStart(&me, &peer, clientIdentDone, connState);
#endif
        commSetSelect(fd, COMM_SELECT_READ, clientReadRequest, connState, 0);
        commSetDefer(fd, clientReadDefer, connState);
        clientdbEstablished(peer.sin_addr, 1);
        assert(N);
        (*N)++;
    }
}

#define SENDING_BODY 0
#define SENDING_HDRSONLY 1
static int
clientCheckTransferDone(clientHttpRequest * http)
{
    int sending = SENDING_BODY;
    StoreEntry *entry = http->entry;
    MemObject *mem;
    http_reply *reply;
    int sendlen;
    if (entry == NULL)
        return 0;
    /*
     * For now, 'done_copying' is used for special cases like
     * Range and HEAD requests.
     */
    if (http->flags.done_copying)
        return 1;
    /*
     * Handle STORE_OK objects.
     * objectLen(entry) will be set proprely.
     */
    if (entry->store_status == STORE_OK) {
        if (http->out.offset >= objectLen(entry))
            return 1;
        else
            return 0;
    }
    /*
     * Now, handle STORE_PENDING objects
     */
    mem = entry->mem_obj;
    assert(mem != NULL);
    assert(http->request != NULL);
    reply = mem->reply;
    if (reply->hdr_sz == 0)
        return 0;               /* haven't found end of headers yet */
    else if (reply->sline.status == HTTP_OK)
        sending = SENDING_BODY;
    else if (reply->sline.status == HTTP_NO_CONTENT)
        sending = SENDING_HDRSONLY;
    else if (reply->sline.status == HTTP_NOT_MODIFIED)
        sending = SENDING_HDRSONLY;
    else if (reply->sline.status < HTTP_OK)
        sending = SENDING_HDRSONLY;
    else if (http->request->method == METHOD_HEAD)
        sending = SENDING_HDRSONLY;
    else
        sending = SENDING_BODY;
    /*
     * Figure out how much data we are supposed to send.
     * If we are sending a body and we don't have a content-length,
     * then we must wait for the object to become STORE_OK.
     */
    if (sending == SENDING_HDRSONLY)
        sendlen = reply->hdr_sz;
    else if (reply->content_length < 0)
        return 0;
    else
        sendlen = reply->content_length + reply->hdr_sz;
    /*
     * Now that we have the expected length, did we send it all?
     */
    if (http->out.offset < sendlen)
        return 0;
    else
        return 1;
}

static int
clientGotNotEnough(clientHttpRequest * http)
{
    int cl = httpReplyBodySize(http->request->method, http->entry->mem_obj->reply);
    int hs = http->entry->mem_obj->reply->hdr_sz;
    assert(cl >= 0);
    if (http->out.offset < cl + hs)
        return 1;
    return 0;
}

/*
 * This function is designed to serve a fairly specific purpose.
 * Occasionally our vBNS-connected caches can talk to each other, but not
 * the rest of the world.  Here we try to detect frequent failures which
 * make the cache unusable (e.g. DNS lookup and connect() failures).  If
 * the failure:success ratio goes above 1.0 then we go into "hit only"
 * mode where we only return UDP_HIT or UDP_MISS_NOFETCH.  Neighbors
 * will only fetch HITs from us if they are using the ICP protocol.  We
 * stay in this mode for 5 minutes.
 * 
 * Duane W., Sept 16, 1996
 */

static void
checkFailureRatio(err_type etype, hier_code hcode)
{
    static double magic_factor = 100.0;
    double n_good;
    double n_bad;
    if (hcode == HIER_NONE)
        return;
    n_good = magic_factor / (1.0 + request_failure_ratio);
    n_bad = magic_factor - n_good;
    switch (etype) {
    case ERR_DNS_FAIL:
    case ERR_CONNECT_FAIL:
    case ERR_READ_ERROR:
        n_bad++;
        break;
    default:
        n_good++;
    }
    request_failure_ratio = n_bad / n_good;
    if (hit_only_mode_until > squid_curtime)
        return;
    if (request_failure_ratio < 1.0)
        return;
    debug(33, 0) ("Failure Ratio at %4.2f\n", request_failure_ratio);
    debug(33, 0) ("Going into hit-only-mode for %d minutes...\n",
        FAILURE_MODE_TIME / 60);
    hit_only_mode_until = squid_curtime + FAILURE_MODE_TIME;
    request_failure_ratio = 0.8;        /* reset to something less than 1.0 */
}

void
clientHttpConnectionsOpen(void)
{
    sockaddr_in_list *s;
    int fd;
    for (s = Config.Sockaddr.http; s; s = s->next) {
        if (MAXHTTPPORTS == NHttpSockets) {
            debug(1, 1) ("WARNING: You have too many 'http_port' lines.\n");
            debug(1, 1) ("         The limit is %d\n", MAXHTTPPORTS);
            continue;
        }
        enter_suid();
        fd = comm_open(SOCK_STREAM,
            0,
            s->s.sin_addr,
            ntohs(s->s.sin_port),
            COMM_NONBLOCKING,
            "HTTP Socket");
        leave_suid();
        if (fd < 0)
            continue;
        comm_listen(fd);
        commSetSelect(fd, COMM_SELECT_READ, httpAccept, NULL, 0);
        /*
         * We need to set a defer handler here so that we don't
         * peg the CPU with select() when we hit the FD limit.
         */
        commSetDefer(fd, httpAcceptDefer, NULL);
        debug(1, 1) ("Accepting HTTP connections at %s, port %d, FD %d.\n",
            inet_ntoa(s->s.sin_addr),
            (int) ntohs(s->s.sin_port),
            fd);
        HttpSockets[NHttpSockets++] = fd;
    }
    if (NHttpSockets < 1)
        fatal("Cannot open HTTP Port");
}

void
clientHttpConnectionsClose(void)
{
    int i;
    for (i = 0; i < NHttpSockets; i++) {
        if (HttpSockets[i] >= 0) {
            debug(1, 1) ("FD %d Closing HTTP connection\n", HttpSockets[i]);
            comm_close(HttpSockets[i]);
            HttpSockets[i] = -1;
        }
    }
    NHttpSockets = 0;
}