When using OpenSSL, trust intermediate CAs from trusted stores (#383)

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

/*
 * Copyright (C) 1996-2019 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/* DEBUG: section 85    Client-side Request Routines */

/*
 * General logic of request processing:
 *
 * We run a series of tests to determine if access will be permitted, and to do
 * any redirection. Then we call into the result clientStream to retrieve data.
 * From that point on it's up to reply management.
 */

#include "squid.h"
#include "acl/FilledChecklist.h"
#include "acl/Gadgets.h"
#include "anyp/PortCfg.h"
#include "base/AsyncJobCalls.h"
#include "client_side.h"
#include "client_side_reply.h"
#include "client_side_request.h"
#include "ClientRequestContext.h"
#include "clientStream.h"
#include "comm/Connection.h"
#include "comm/Write.h"
#include "err_detail_type.h"
#include "errorpage.h"
#include "fd.h"
#include "fde.h"
#include "format/Token.h"
#include "gopher.h"
#include "helper.h"
#include "helper/Reply.h"
#include "http.h"
#include "http/Stream.h"
#include "HttpHdrCc.h"
#include "HttpReply.h"
#include "HttpRequest.h"
#include "ip/NfMarkConfig.h"
#include "ip/QosConfig.h"
#include "ipcache.h"
#include "log/access_log.h"
#include "MemObject.h"
#include "Parsing.h"
#include "profiler/Profiler.h"
#include "proxyp/Header.h"
#include "redirect.h"
#include "rfc1738.h"
#include "SquidConfig.h"
#include "SquidTime.h"
#include "Store.h"
#include "StrList.h"
#include "tools.h"
#include "wordlist.h"
#if USE_AUTH
#include "auth/UserRequest.h"
#endif
#if USE_ADAPTATION
#include "adaptation/AccessCheck.h"
#include "adaptation/Answer.h"
#include "adaptation/Iterator.h"
#include "adaptation/Service.h"
#if ICAP_CLIENT
#include "adaptation/icap/History.h"
#endif
#endif
#if USE_OPENSSL
#include "ssl/ServerBump.h"
#include "ssl/support.h"
#endif

#if LINGERING_CLOSE
#define comm_close comm_lingering_close
#endif

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

#if FOLLOW_X_FORWARDED_FOR
static void clientFollowXForwardedForCheck(allow_t answer, void *data);
#endif /* FOLLOW_X_FORWARDED_FOR */

ErrorState *clientBuildError(err_type, Http::StatusCode, char const *url, Ip::Address &, HttpRequest *, const AccessLogEntry::Pointer &);

CBDATA_CLASS_INIT(ClientRequestContext);

/* Local functions */
/* other */
static void clientAccessCheckDoneWrapper(allow_t, void *);
#if USE_OPENSSL
static void sslBumpAccessCheckDoneWrapper(allow_t, void *);
#endif
static int clientHierarchical(ClientHttpRequest * http);
static void clientInterpretRequestHeaders(ClientHttpRequest * http);
static HLPCB clientRedirectDoneWrapper;
static HLPCB clientStoreIdDoneWrapper;
static void checkNoCacheDoneWrapper(allow_t, void *);
SQUIDCEXTERN CSR clientGetMoreData;
SQUIDCEXTERN CSS clientReplyStatus;
SQUIDCEXTERN CSD clientReplyDetach;
static void checkFailureRatio(err_type, hier_code);

ClientRequestContext::~ClientRequestContext()
{
    /*
     * Release our "lock" on our parent, ClientHttpRequest, if we
     * still have one
     */

    if (http)
        cbdataReferenceDone(http);

    delete error;
    debugs(85,3, "ClientRequestContext destructed, this=" << this);
}

ClientRequestContext::ClientRequestContext(ClientHttpRequest *anHttp) :
    http(cbdataReference(anHttp)),
    acl_checklist(NULL),
    redirect_state(REDIRECT_NONE),
    store_id_state(REDIRECT_NONE),
    host_header_verify_done(false),
    http_access_done(false),
    adapted_http_access_done(false),
#if USE_ADAPTATION
    adaptation_acl_check_done(false),
#endif
    redirect_done(false),
    store_id_done(false),
    no_cache_done(false),
    interpreted_req_hdrs(false),
    toClientMarkingDone(false),
#if USE_OPENSSL
    sslBumpCheckDone(false),
#endif
    error(NULL),
    readNextRequest(false)
{
    debugs(85, 3, "ClientRequestContext constructed, this=" << this);
}

CBDATA_CLASS_INIT(ClientHttpRequest);

ClientHttpRequest::ClientHttpRequest(ConnStateData * aConn) :
#if USE_ADAPTATION
    AsyncJob("ClientHttpRequest"),
#endif
    request(NULL),
    uri(NULL),
    log_uri(NULL),
    req_sz(0),
    calloutContext(NULL),
    maxReplyBodySize_(0),
    entry_(NULL),
    loggingEntry_(NULL),
    conn_(NULL)
#if USE_OPENSSL
    , sslBumpNeed_(Ssl::bumpEnd)
#endif
#if USE_ADAPTATION
    , request_satisfaction_mode(false)
    , request_satisfaction_offset(0)
#endif
{
    setConn(aConn);
    al = new AccessLogEntry;
    al->cache.start_time = current_time;
    if (aConn) {
        al->tcpClient = clientConnection = aConn->clientConnection;
        al->cache.port = aConn->port;
        al->cache.caddr = aConn->log_addr;
        al->proxyProtocolHeader = aConn->proxyProtocolHeader();

#if USE_OPENSSL
        if (aConn->clientConnection != NULL && aConn->clientConnection->isOpen()) {
            if (auto ssl = fd_table[aConn->clientConnection->fd].ssl.get())
                al->cache.sslClientCert.resetWithoutLocking(SSL_get_peer_certificate(ssl));
        }
#endif
    }
    dlinkAdd(this, &active, &ClientActiveRequests);
}

/*
 * returns true if client specified that the object must come from the cache
 * without contacting origin server
 */
bool
ClientHttpRequest::onlyIfCached()const
{
    assert(request);
    return request->cache_control &&
           request->cache_control->hasOnlyIfCached();
}

/**
 * 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)
{
    // Can be set at compile time with -D compiler flag
#ifndef FAILURE_MODE_TIME
#define FAILURE_MODE_TIME 300
#endif

    if (hcode == HIER_NONE)
        return;

    // don't bother when ICP is disabled.
    if (Config.Port.icp <= 0)
        return;

    static double magic_factor = 100.0;
    double n_good;
    double n_bad;

    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_SECURE_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;

    debugs(33, DBG_CRITICAL, "WARNING: Failure Ratio at "<< std::setw(4)<<
           std::setprecision(3) << request_failure_ratio);

    debugs(33, DBG_CRITICAL, "WARNING: ICP going into HIT-only mode for " <<
           FAILURE_MODE_TIME / 60 << " minutes...");

    hit_only_mode_until = squid_curtime + FAILURE_MODE_TIME;

    request_failure_ratio = 0.8;    /* reset to something less than 1.0 */
}

ClientHttpRequest::~ClientHttpRequest()
{
    debugs(33, 3, "httpRequestFree: " << uri);
    PROF_start(httpRequestFree);

    // Even though freeResources() below may destroy the request,
    // we no longer set request->body_pipe to NULL here
    // because we did not initiate that pipe (ConnStateData did)

    /* the ICP check here was erroneous
     * - StoreEntry::releaseRequest was always called if entry was valid
     */

    logRequest();

    loggingEntry(NULL);

    if (request)
        checkFailureRatio(request->errType, al->hier.code);

    freeResources();

#if USE_ADAPTATION
    announceInitiatorAbort(virginHeadSource);

    if (adaptedBodySource != NULL)
        stopConsumingFrom(adaptedBodySource);
#endif

    if (calloutContext)
        delete calloutContext;

    clientConnection = NULL;

    if (conn_)
        cbdataReferenceDone(conn_);

    /* moving to the next connection is handled by the context free */
    dlinkDelete(&active, &ClientActiveRequests);

    PROF_stop(httpRequestFree);
}

/**
 * Create a request and kick it off
 *
 * \retval 0     success
 * \retval -1    failure
 *
 * TODO: Pass in the buffers to be used in the inital Read request, as they are
 * determined by the user
 */
int
clientBeginRequest(const HttpRequestMethod& method, char const *url, CSCB * streamcallback,
                   CSD * streamdetach, ClientStreamData streamdata, HttpHeader const *header,
                   char *tailbuf, size_t taillen, const MasterXaction::Pointer &mx)
{
    size_t url_sz;
    ClientHttpRequest *http = new ClientHttpRequest(NULL);
    HttpRequest *request;
    StoreIOBuffer tempBuffer;
    if (http->al != NULL)
        http->al->cache.start_time = current_time;
    /* this is only used to adjust the connection offset in client_side.c */
    http->req_sz = 0;
    tempBuffer.length = taillen;
    tempBuffer.data = tailbuf;
    /* client stream setup */
    clientStreamInit(&http->client_stream, clientGetMoreData, clientReplyDetach,
                     clientReplyStatus, new clientReplyContext(http), streamcallback,
                     streamdetach, streamdata, tempBuffer);
    /* make it visible in the 'current acctive requests list' */
    /* Set flags */
    /* internal requests only makes sense in an
     * accelerator today. TODO: accept flags ? */
    http->flags.accel = true;
    /* allow size for url rewriting */
    url_sz = strlen(url) + Config.appendDomainLen + 5;
    http->uri = (char *)xcalloc(url_sz, 1);
    strcpy(http->uri, url); // XXX: polluting http->uri before parser validation

    if ((request = HttpRequest::FromUrl(http->uri, mx, method)) == NULL) {
        debugs(85, 5, "Invalid URL: " << http->uri);
        return -1;
    }

    /*
     * now update the headers in request with our supplied headers.
     * HttpRequest::FromUrl() should return a blank header set, but
     * we use Update to be sure of correctness.
     */
    if (header)
        request->header.update(header);

    /* http struct now ready */

    /*
     * build new header list *? TODO
     */
    request->flags.accelerated = http->flags.accel;

    /* this is an internally created
     * request, not subject to acceleration
     * target overrides */
    /*
     * FIXME? Do we want to detect and handle internal requests of internal
     * objects ?
     */

    /* Internally created requests cannot have bodies today */
    request->content_length = 0;

    request->client_addr.setNoAddr();

#if FOLLOW_X_FORWARDED_FOR
    request->indirect_client_addr.setNoAddr();
#endif /* FOLLOW_X_FORWARDED_FOR */

    request->my_addr.setNoAddr();   /* undefined for internal requests */

    request->my_addr.port(0);

    request->http_ver = Http::ProtocolVersion();

    http->initRequest(request);

    /* optional - skip the access check ? */
    http->calloutContext = new ClientRequestContext(http);

    http->calloutContext->http_access_done = false;

    http->calloutContext->redirect_done = true;

    http->calloutContext->no_cache_done = true;

    http->doCallouts();

    return 0;
}

bool
ClientRequestContext::httpStateIsValid()
{
    ClientHttpRequest *http_ = http;

    if (cbdataReferenceValid(http_))
        return true;

    http = NULL;

    cbdataReferenceDone(http_);

    return false;
}

#if FOLLOW_X_FORWARDED_FOR
/**
 * clientFollowXForwardedForCheck() checks the content of X-Forwarded-For:
 * against the followXFF ACL, or cleans up and passes control to
 * clientAccessCheck().
 *
 * The trust model here is a little ambiguous. So to clarify the logic:
 * - we may always use the direct client address as the client IP.
 * - these trust tests merey tell whether we trust given IP enough to believe the
 *   IP string which it appended to the X-Forwarded-For: header.
 * - if at any point we don't trust what an IP adds we stop looking.
 * - at that point the current contents of indirect_client_addr are the value set
 *   by the last previously trusted IP.
 * ++ indirect_client_addr contains the remote direct client from the trusted peers viewpoint.
 */
static void
clientFollowXForwardedForCheck(allow_t answer, void *data)
{
    ClientRequestContext *calloutContext = (ClientRequestContext *) data;

    if (!calloutContext->httpStateIsValid())
        return;

    ClientHttpRequest *http = calloutContext->http;
    HttpRequest *request = http->request;

    if (answer.allowed() && request->x_forwarded_for_iterator.size() != 0) {

        /*
         * Remove the last comma-delimited element from the
         * x_forwarded_for_iterator and use it to repeat the cycle.
         */
        const char *p;
        const char *asciiaddr;
        int l;
        Ip::Address addr;
        p = request->x_forwarded_for_iterator.termedBuf();
        l = request->x_forwarded_for_iterator.size();

        /*
        * XXX x_forwarded_for_iterator should really be a list of
        * IP addresses, but it's a String instead.  We have to
        * walk backwards through the String, biting off the last
        * comma-delimited part each time.  As long as the data is in
        * a String, we should probably implement and use a variant of
        * strListGetItem() that walks backwards instead of forwards
        * through a comma-separated list.  But we don't even do that;
        * we just do the work in-line here.
        */
        /* skip trailing space and commas */
        while (l > 0 && (p[l-1] == ',' || xisspace(p[l-1])))
            --l;
        request->x_forwarded_for_iterator.cut(l);
        /* look for start of last item in list */
        while (l > 0 && ! (p[l-1] == ',' || xisspace(p[l-1])))
            --l;
        asciiaddr = p+l;
        if ((addr = asciiaddr)) {
            request->indirect_client_addr = addr;
            request->x_forwarded_for_iterator.cut(l);
            calloutContext->acl_checklist = clientAclChecklistCreate(Config.accessList.followXFF, http);
            if (!Config.onoff.acl_uses_indirect_client) {
                /* override the default src_addr tested if we have to go deeper than one level into XFF */
                Filled(calloutContext->acl_checklist)->src_addr = request->indirect_client_addr;
            }
            calloutContext->acl_checklist->nonBlockingCheck(clientFollowXForwardedForCheck, data);
            return;
        }
    }

    /* clean up, and pass control to clientAccessCheck */
    if (Config.onoff.log_uses_indirect_client) {
        /*
        * Ensure that the access log shows the indirect client
        * instead of the direct client.
        */
        http->al->cache.caddr = request->indirect_client_addr;
        if (ConnStateData *conn = http->getConn())
            conn->log_addr = request->indirect_client_addr;
    }
    request->x_forwarded_for_iterator.clean();
    request->flags.done_follow_x_forwarded_for = true;

    if (answer.conflicted()) {
        debugs(28, DBG_CRITICAL, "ERROR: Processing X-Forwarded-For. Stopping at IP address: " << request->indirect_client_addr );
    }

    /* process actual access ACL as normal. */
    calloutContext->clientAccessCheck();
}
#endif /* FOLLOW_X_FORWARDED_FOR */

static void
hostHeaderIpVerifyWrapper(const ipcache_addrs* ia, const Dns::LookupDetails &dns, void *data)
{
    ClientRequestContext *c = static_cast<ClientRequestContext*>(data);
    c->hostHeaderIpVerify(ia, dns);
}

void
ClientRequestContext::hostHeaderIpVerify(const ipcache_addrs* ia, const Dns::LookupDetails &dns)
{
    Comm::ConnectionPointer clientConn = http->getConn()->clientConnection;

    // note the DNS details for the transaction stats.
    http->request->recordLookup(dns);

    // Is the NAT destination IP in DNS?
    if (ia && ia->have(clientConn->local)) {
        debugs(85, 3, "validate IP " << clientConn->local << " possible from Host:");
        http->request->flags.hostVerified = true;
        http->doCallouts();
        return;
    }
    debugs(85, 3, HERE << "FAIL: validate IP " << clientConn->local << " possible from Host:");
    hostHeaderVerifyFailed("local IP", "any domain IP");
}

void
ClientRequestContext::hostHeaderVerifyFailed(const char *A, const char *B)
{
    // IP address validation for Host: failed. Admin wants to ignore them.
    // NP: we do not yet handle CONNECT tunnels well, so ignore for them
    if (!Config.onoff.hostStrictVerify && http->request->method != Http::METHOD_CONNECT) {
        debugs(85, 3, "SECURITY ALERT: Host header forgery detected on " << http->getConn()->clientConnection <<
               " (" << A << " does not match " << B << ") on URL: " << http->request->effectiveRequestUri());

        // NP: it is tempting to use 'flags.noCache' but that is all about READing cache data.
        // The problems here are about WRITE for new cache content, which means flags.cachable
        http->request->flags.cachable = false; // MUST NOT cache (for now)
        // XXX: when we have updated the cache key to base on raw-IP + URI this cacheable limit can go.
        http->request->flags.hierarchical = false; // MUST NOT pass to peers (for now)
        // XXX: when we have sorted out the best way to relay requests properly to peers this hierarchical limit can go.
        http->doCallouts();
        return;
    }

    debugs(85, DBG_IMPORTANT, "SECURITY ALERT: Host header forgery detected on " <<
           http->getConn()->clientConnection << " (" << A << " does not match " << B << ")");
    if (const char *ua = http->request->header.getStr(Http::HdrType::USER_AGENT))
        debugs(85, DBG_IMPORTANT, "SECURITY ALERT: By user agent: " << ua);
    debugs(85, DBG_IMPORTANT, "SECURITY ALERT: on URL: " << http->request->effectiveRequestUri());

    // IP address validation for Host: failed. reject the connection.
    clientStreamNode *node = (clientStreamNode *)http->client_stream.tail->prev->data;
    clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
    assert (repContext);
    repContext->setReplyToError(ERR_CONFLICT_HOST, Http::scConflict,
                                http->request->method, NULL,
                                http->getConn()->clientConnection->remote,
                                http->request,
                                NULL,
#if USE_AUTH
                                http->getConn() != NULL && http->getConn()->getAuth() != NULL ?
                                http->getConn()->getAuth() : http->request->auth_user_request);
#else
                                NULL);
#endif
    node = (clientStreamNode *)http->client_stream.tail->data;
    clientStreamRead(node, http, node->readBuffer);
}

void
ClientRequestContext::hostHeaderVerify()
{
    // Require a Host: header.
    const char *host = http->request->header.getStr(Http::HdrType::HOST);

    if (!host) {
        // TODO: dump out the HTTP/1.1 error about missing host header.
        // otherwise this is fine, can't forge a header value when its not even set.
        debugs(85, 3, HERE << "validate skipped with no Host: header present.");
        http->doCallouts();
        return;
    }

    if (http->request->flags.internal) {
        // TODO: kill this when URL handling allows partial URLs out of accel mode
        //       and we no longer screw with the URL just to add our internal host there
        debugs(85, 6, HERE << "validate skipped due to internal composite URL.");
        http->doCallouts();
        return;
    }

    // Locate if there is a port attached, strip ready for IP lookup
    char *portStr = NULL;
    char *hostB = xstrdup(host);
    host = hostB;
    if (host[0] == '[') {
        // IPv6 literal.
        portStr = strchr(hostB, ']');
        if (portStr && *(++portStr) != ':') {
            portStr = NULL;
        }
    } else {
        // Domain or IPv4 literal with port
        portStr = strrchr(hostB, ':');
    }

    uint16_t port = 0;
    if (portStr) {
        *portStr = '\0'; // strip the ':'
        if (*(++portStr) != '\0') {
            char *end = NULL;
            int64_t ret = strtoll(portStr, &end, 10);
            if (end == portStr || *end != '\0' || ret < 1 || ret > 0xFFFF) {
                // invalid port details. Replace the ':'
                *(--portStr) = ':';
                portStr = NULL;
            } else
                port = (ret & 0xFFFF);
        }
    }

    debugs(85, 3, "validate host=" << host << ", port=" << port << ", portStr=" << (portStr?portStr:"NULL"));
    if (http->request->flags.intercepted || http->request->flags.interceptTproxy) {
        // verify the Host: port (if any) matches the apparent destination
        if (portStr && port != http->getConn()->clientConnection->local.port()) {
            debugs(85, 3, "FAIL on validate port " << http->getConn()->clientConnection->local.port() <<
                   " matches Host: port " << port << " (" << portStr << ")");
            hostHeaderVerifyFailed("intercepted port", portStr);
        } else {
            // XXX: match the scheme default port against the apparent destination

            // verify the destination DNS is one of the Host: headers IPs
            ipcache_nbgethostbyname(host, hostHeaderIpVerifyWrapper, this);
        }
    } else if (!Config.onoff.hostStrictVerify) {
        debugs(85, 3, "validate skipped.");
        http->doCallouts();
    } else if (strlen(host) != strlen(http->request->url.host())) {
        // Verify forward-proxy requested URL domain matches the Host: header
        debugs(85, 3, "FAIL on validate URL domain length " << http->request->url.host() << " matches Host: " << host);
        hostHeaderVerifyFailed(host, http->request->url.host());
    } else if (matchDomainName(host, http->request->url.host()) != 0) {
        // Verify forward-proxy requested URL domain matches the Host: header
        debugs(85, 3, "FAIL on validate URL domain " << http->request->url.host() << " matches Host: " << host);
        hostHeaderVerifyFailed(host, http->request->url.host());
    } else if (portStr && port != http->request->url.port()) {
        // Verify forward-proxy requested URL domain matches the Host: header
        debugs(85, 3, "FAIL on validate URL port " << http->request->url.port() << " matches Host: port " << portStr);
        hostHeaderVerifyFailed("URL port", portStr);
    } else if (!portStr && http->request->method != Http::METHOD_CONNECT && http->request->url.port() != http->request->url.getScheme().defaultPort()) {
        // Verify forward-proxy requested URL domain matches the Host: header
        // Special case: we don't have a default-port to check for CONNECT. Assume URL is correct.
        debugs(85, 3, "FAIL on validate URL port " << http->request->url.port() << " matches Host: default port " << http->request->url.getScheme().defaultPort());
        hostHeaderVerifyFailed("URL port", "default port");
    } else {
        // Okay no problem.
        debugs(85, 3, "validate passed.");
        http->request->flags.hostVerified = true;
        http->doCallouts();
    }
    safe_free(hostB);
}

/* This is the entry point for external users of the client_side routines */
void
ClientRequestContext::clientAccessCheck()
{
#if FOLLOW_X_FORWARDED_FOR
    if (!http->request->flags.doneFollowXff() &&
            Config.accessList.followXFF &&
            http->request->header.has(Http::HdrType::X_FORWARDED_FOR)) {

        /* we always trust the direct client address for actual use */
        http->request->indirect_client_addr = http->request->client_addr;
        http->request->indirect_client_addr.port(0);

        /* setup the XFF iterator for processing */
        http->request->x_forwarded_for_iterator = http->request->header.getList(Http::HdrType::X_FORWARDED_FOR);

        /* begin by checking to see if we trust direct client enough to walk XFF */
        acl_checklist = clientAclChecklistCreate(Config.accessList.followXFF, http);
        acl_checklist->nonBlockingCheck(clientFollowXForwardedForCheck, this);
        return;
    }
#endif

    if (Config.accessList.http) {
        acl_checklist = clientAclChecklistCreate(Config.accessList.http, http);
        acl_checklist->nonBlockingCheck(clientAccessCheckDoneWrapper, this);
    } else {
        debugs(0, DBG_CRITICAL, "No http_access configuration found. This will block ALL traffic");
        clientAccessCheckDone(ACCESS_DENIED);
    }
}

/**
 * Identical in operation to clientAccessCheck() but performed later using different configured ACL list.
 * The default here is to allow all. Since the earlier http_access should do a default deny all.
 * This check is just for a last-minute denial based on adapted request headers.
 */
void
ClientRequestContext::clientAccessCheck2()
{
    if (Config.accessList.adapted_http) {
        acl_checklist = clientAclChecklistCreate(Config.accessList.adapted_http, http);
        acl_checklist->nonBlockingCheck(clientAccessCheckDoneWrapper, this);
    } else {
        debugs(85, 2, HERE << "No adapted_http_access configuration. default: ALLOW");
        clientAccessCheckDone(ACCESS_ALLOWED);
    }
}

void
clientAccessCheckDoneWrapper(allow_t answer, void *data)
{
    ClientRequestContext *calloutContext = (ClientRequestContext *) data;

    if (!calloutContext->httpStateIsValid())
        return;

    calloutContext->clientAccessCheckDone(answer);
}

void
ClientRequestContext::clientAccessCheckDone(const allow_t &answer)
{
    acl_checklist = NULL;
    err_type page_id;
    Http::StatusCode status;
    debugs(85, 2, "The request " << http->request->method << ' ' <<
           http->uri << " is " << answer <<
           "; last ACL checked: " << (AclMatchedName ? AclMatchedName : "[none]"));

#if USE_AUTH
    char const *proxy_auth_msg = "<null>";
    if (http->getConn() != NULL && http->getConn()->getAuth() != NULL)
        proxy_auth_msg = http->getConn()->getAuth()->denyMessage("<null>");
    else if (http->request->auth_user_request != NULL)
        proxy_auth_msg = http->request->auth_user_request->denyMessage("<null>");
#endif

    if (!answer.allowed()) {
        // auth has a grace period where credentials can be expired but okay not to challenge.

        /* Send an auth challenge or error */
        // XXX: do we still need aclIsProxyAuth() ?
        bool auth_challenge = (answer == ACCESS_AUTH_REQUIRED || aclIsProxyAuth(AclMatchedName));
        debugs(85, 5, "Access Denied: " << http->uri);
        debugs(85, 5, "AclMatchedName = " << (AclMatchedName ? AclMatchedName : "<null>"));
#if USE_AUTH
        if (auth_challenge)
            debugs(33, 5, "Proxy Auth Message = " << (proxy_auth_msg ? proxy_auth_msg : "<null>"));
#endif

        /*
         * 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, answer != ACCESS_AUTH_REQUIRED);

        http->logType.update(LOG_TCP_DENIED);

        if (auth_challenge) {
#if USE_AUTH
            if (http->request->flags.sslBumped) {
                /*SSL Bumped request, authentication is not possible*/
                status = Http::scForbidden;
            } else if (!http->flags.accel) {
                /* Proxy authorisation needed */
                status = Http::scProxyAuthenticationRequired;
            } else {
                /* WWW authorisation needed */
                status = Http::scUnauthorized;
            }
#else
            // need auth, but not possible to do.
            status = Http::scForbidden;
#endif
            if (page_id == ERR_NONE)
                page_id = ERR_CACHE_ACCESS_DENIED;
        } else {
            status = Http::scForbidden;

            if (page_id == ERR_NONE)
                page_id = ERR_ACCESS_DENIED;
        }

        Ip::Address tmpnoaddr;
        tmpnoaddr.setNoAddr();
        error = clientBuildError(page_id, status,
                                 NULL,
                                 http->getConn() != NULL ? http->getConn()->clientConnection->remote : tmpnoaddr,
                                 http->request, http->al
                                );

#if USE_AUTH
        error->auth_user_request =
            http->getConn() != NULL && http->getConn()->getAuth() != NULL ?
            http->getConn()->getAuth() : http->request->auth_user_request;
#endif

        readNextRequest = true;
    }

    /* ACCESS_ALLOWED continues here ... */
    xfree(http->uri);
    http->uri = SBufToCstring(http->request->effectiveRequestUri());
    http->doCallouts();
}

#if USE_ADAPTATION
void
ClientHttpRequest::noteAdaptationAclCheckDone(Adaptation::ServiceGroupPointer g)
{
    debugs(93,3,HERE << this << " adaptationAclCheckDone called");

#if ICAP_CLIENT
    Adaptation::Icap::History::Pointer ih = request->icapHistory();
    if (ih != NULL) {
        if (getConn() != NULL && getConn()->clientConnection != NULL) {
            ih->rfc931 = getConn()->clientConnection->rfc931;
#if USE_OPENSSL
            if (getConn()->clientConnection->isOpen()) {
                ih->ssluser = sslGetUserEmail(fd_table[getConn()->clientConnection->fd].ssl.get());
            }
#endif
        }
        ih->log_uri = log_uri;
        ih->req_sz = req_sz;
    }
#endif

    if (!g) {
        debugs(85,3, HERE << "no adaptation needed");
        doCallouts();
        return;
    }

    startAdaptation(g);
}

#endif

static void
clientRedirectAccessCheckDone(allow_t answer, void *data)
{
    ClientRequestContext *context = (ClientRequestContext *)data;
    ClientHttpRequest *http = context->http;
    context->acl_checklist = NULL;

    if (answer.allowed())
        redirectStart(http, clientRedirectDoneWrapper, context);
    else {
        Helper::Reply const nilReply(Helper::Error);
        context->clientRedirectDone(nilReply);
    }
}

void
ClientRequestContext::clientRedirectStart()
{
    debugs(33, 5, HERE << "'" << http->uri << "'");
    http->al->syncNotes(http->request);
    if (Config.accessList.redirector) {
        acl_checklist = clientAclChecklistCreate(Config.accessList.redirector, http);
        acl_checklist->nonBlockingCheck(clientRedirectAccessCheckDone, this);
    } else
        redirectStart(http, clientRedirectDoneWrapper, this);
}

/**
 * This methods handles Access checks result of StoreId access list.
 * Will handle as "ERR" (no change) in a case Access is not allowed.
 */
static void
clientStoreIdAccessCheckDone(allow_t answer, void *data)
{
    ClientRequestContext *context = static_cast<ClientRequestContext *>(data);
    ClientHttpRequest *http = context->http;
    context->acl_checklist = NULL;

    if (answer.allowed())
        storeIdStart(http, clientStoreIdDoneWrapper, context);
    else {
        debugs(85, 3, "access denied expected ERR reply handling: " << answer);
        Helper::Reply const nilReply(Helper::Error);
        context->clientStoreIdDone(nilReply);
    }
}

/**
 * Start locating an alternative storeage ID string (if any) from admin
 * configured helper program. This is an asynchronous operation terminating in
 * ClientRequestContext::clientStoreIdDone() when completed.
 */
void
ClientRequestContext::clientStoreIdStart()
{
    debugs(33, 5,"'" << http->uri << "'");

    if (Config.accessList.store_id) {
        acl_checklist = clientAclChecklistCreate(Config.accessList.store_id, http);
        acl_checklist->nonBlockingCheck(clientStoreIdAccessCheckDone, this);
    } else
        storeIdStart(http, clientStoreIdDoneWrapper, this);
}

static int
clientHierarchical(ClientHttpRequest * http)
{
    HttpRequest *request = http->request;
    HttpRequestMethod method = request->method;

    // intercepted requests MUST NOT (yet) be sent to peers unless verified
    if (!request->flags.hostVerified && (request->flags.intercepted || request->flags.interceptTproxy))
        return 0;

    /*
     * 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;

    /*
     * This is incorrect: authenticating requests can be sent via a hierarchy
     * (they can even be cached if the correct headers are set on the reply)
     */
    if (request->flags.auth)
        return 0;

    if (method == Http::METHOD_TRACE)
        return 1;

    if (method != Http::METHOD_GET)
        return 0;

    if (request->flags.loopDetected)
        return 0;

    if (request->url.getScheme() == AnyP::PROTO_HTTP)
        return method.respMaybeCacheable();

    if (request->url.getScheme() == AnyP::PROTO_GOPHER)
        return gopherCachable(request);

    if (request->url.getScheme() == AnyP::PROTO_CACHE_OBJECT)
        return 0;

    return 1;
}

static void
clientCheckPinning(ClientHttpRequest * http)
{
    HttpRequest *request = http->request;
    HttpHeader *req_hdr = &request->header;
    ConnStateData *http_conn = http->getConn();

    /* Internal requests such as those from ESI includes may be without
     * a client connection
     */
    if (!http_conn)
        return;

    request->flags.connectionAuthDisabled = http_conn->port->connection_auth_disabled;
    if (!request->flags.connectionAuthDisabled) {
        if (Comm::IsConnOpen(http_conn->pinning.serverConnection)) {
            if (http_conn->pinning.auth) {
                request->flags.connectionAuth = true;
                request->flags.auth = true;
            } else {
                request->flags.connectionProxyAuth = true;
            }
            // These should already be linked correctly.
            assert(request->clientConnectionManager == http_conn);
        }
    }

    /* check if connection auth is used, and flag as candidate for pinning
     * in such case.
     * Note: we may need to set flags.connectionAuth even if the connection
     * is already pinned if it was pinned earlier due to proxy auth
     */
    if (!request->flags.connectionAuth) {
        if (req_hdr->has(Http::HdrType::AUTHORIZATION) || req_hdr->has(Http::HdrType::PROXY_AUTHORIZATION)) {
            HttpHeaderPos pos = HttpHeaderInitPos;
            HttpHeaderEntry *e;
            int may_pin = 0;
            while ((e = req_hdr->getEntry(&pos))) {
                if (e->id == Http::HdrType::AUTHORIZATION || e->id == Http::HdrType::PROXY_AUTHORIZATION) {
                    const char *value = e->value.rawBuf();
                    if (strncasecmp(value, "NTLM ", 5) == 0
                            ||
                            strncasecmp(value, "Negotiate ", 10) == 0
                            ||
                            strncasecmp(value, "Kerberos ", 9) == 0) {
                        if (e->id == Http::HdrType::AUTHORIZATION) {
                            request->flags.connectionAuth = true;
                            may_pin = 1;
                        } else {
                            request->flags.connectionProxyAuth = true;
                            may_pin = 1;
                        }
                    }
                }
            }
            if (may_pin && !request->pinnedConnection()) {
                // These should already be linked correctly. Just need the ServerConnection to pinn.
                assert(request->clientConnectionManager == http_conn);
            }
        }
    }
}

static void
clientInterpretRequestHeaders(ClientHttpRequest * http)
{
    HttpRequest *request = http->request;
    HttpHeader *req_hdr = &request->header;
    bool no_cache = false;

    request->imslen = -1;
    request->ims = req_hdr->getTime(Http::HdrType::IF_MODIFIED_SINCE);

    if (request->ims > 0)
        request->flags.ims = true;

    if (!request->flags.ignoreCc) {
        if (request->cache_control) {
            if (request->cache_control->hasNoCache())
                no_cache=true;

            // RFC 2616: treat Pragma:no-cache as if it was Cache-Control:no-cache when Cache-Control is missing
        } else if (req_hdr->has(Http::HdrType::PRAGMA))
            no_cache = req_hdr->hasListMember(Http::HdrType::PRAGMA,"no-cache",',');
    }

    if (request->method == Http::METHOD_OTHER) {
        no_cache=true;
    }

    if (no_cache) {
#if USE_HTTP_VIOLATIONS

        if (Config.onoff.reload_into_ims)
            request->flags.nocacheHack = true;
        else if (refresh_nocache_hack)
            request->flags.nocacheHack = true;
        else
#endif

            request->flags.noCache = true;
    }

    /* ignore range header in non-GETs or non-HEADs */
    if (request->method == Http::METHOD_GET || request->method == Http::METHOD_HEAD) {
        // XXX: initialize if we got here without HttpRequest::parseHeader()
        if (!request->range)
            request->range = req_hdr->getRange();

        if (request->range) {
            request->flags.isRanged = true;
            clientStreamNode *node = (clientStreamNode *)http->client_stream.tail->data;
            /* XXX: This is suboptimal. We should give the stream the range set,
             * and thereby let the top of the stream set the offset when the
             * size becomes known. As it is, we will end up requesting from 0
             * for evey -X range specification.
             * RBC - this may be somewhat wrong. We should probably set the range
             * iter up at this point.
             */
            node->readBuffer.offset = request->range->lowestOffset(0);
            http->range_iter.pos = request->range->begin();
            http->range_iter.end = request->range->end();
            http->range_iter.valid = true;
        }
    }

    /* Only HEAD and GET requests permit a Range or Request-Range header.
     * If these headers appear on any other type of request, delete them now.
     */
    else {
        req_hdr->delById(Http::HdrType::RANGE);
        req_hdr->delById(Http::HdrType::REQUEST_RANGE);
        request->ignoreRange("neither HEAD nor GET");
    }

    if (req_hdr->has(Http::HdrType::AUTHORIZATION))
        request->flags.auth = true;

    clientCheckPinning(http);

    if (!request->url.userInfo().isEmpty())
        request->flags.auth = true;

    if (req_hdr->has(Http::HdrType::VIA)) {
        String s = req_hdr->getList(Http::HdrType::VIA);
        /*
         * ThisCache cannot be a member of Via header, "1.1 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.loopDetected = true;
        }

#if USE_FORW_VIA_DB
        fvdbCountVia(s.termedBuf());

#endif

        s.clean();
    }

#if USE_FORW_VIA_DB

    if (req_hdr->has(Http::HdrType::X_FORWARDED_FOR)) {
        String s = req_hdr->getList(Http::HdrType::X_FORWARDED_FOR);
        fvdbCountForw(s.termedBuf());
        s.clean();
    }

#endif

    request->flags.cachable = http->request->maybeCacheable();

    if (clientHierarchical(http))
        request->flags.hierarchical = true;

    debugs(85, 5, "clientInterpretRequestHeaders: REQ_NOCACHE = " <<
           (request->flags.noCache ? "SET" : "NOT SET"));
    debugs(85, 5, "clientInterpretRequestHeaders: REQ_CACHABLE = " <<
           (request->flags.cachable ? "SET" : "NOT SET"));
    debugs(85, 5, "clientInterpretRequestHeaders: REQ_HIERARCHICAL = " <<
           (request->flags.hierarchical ? "SET" : "NOT SET"));

}

void
clientRedirectDoneWrapper(void *data, const Helper::Reply &result)
{
    ClientRequestContext *calloutContext = (ClientRequestContext *)data;

    if (!calloutContext->httpStateIsValid())
        return;

    calloutContext->clientRedirectDone(result);
}

void
clientStoreIdDoneWrapper(void *data, const Helper::Reply &result)
{
    ClientRequestContext *calloutContext = (ClientRequestContext *)data;

    if (!calloutContext->httpStateIsValid())
        return;

    calloutContext->clientStoreIdDone(result);
}

void
ClientRequestContext::clientRedirectDone(const Helper::Reply &reply)
{
    HttpRequest *old_request = http->request;
    debugs(85, 5, HERE << "'" << http->uri << "' result=" << reply);
    assert(redirect_state == REDIRECT_PENDING);
    redirect_state = REDIRECT_DONE;

    // Put helper response Notes into the transaction state record (ALE) eventually
    // do it early to ensure that no matter what the outcome the notes are present.
    if (http->al)
        http->al->syncNotes(old_request);

    UpdateRequestNotes(http->getConn(), *old_request, reply.notes);

    switch (reply.result) {
    case Helper::TimedOut:
        if (Config.onUrlRewriteTimeout.action != toutActBypass) {
            http->calloutsError(ERR_GATEWAY_FAILURE, ERR_DETAIL_REDIRECTOR_TIMEDOUT);
            debugs(85, DBG_IMPORTANT, "ERROR: URL rewrite helper: Timedout");
        }
        break;

    case Helper::Unknown:
    case Helper::TT:
        // Handler in redirect.cc should have already mapped Unknown
        // IF it contained valid entry for the old URL-rewrite helper protocol
        debugs(85, DBG_IMPORTANT, "ERROR: URL rewrite helper returned invalid result code. Wrong helper? " << reply);
        break;

    case Helper::BrokenHelper:
        debugs(85, DBG_IMPORTANT, "ERROR: URL rewrite helper: " << reply);
        break;

    case Helper::Error:
        // no change to be done.
        break;

    case Helper::Okay: {
        // #1: redirect with a specific status code    OK status=NNN url="..."
        // #2: redirect with a default status code     OK url="..."
        // #3: re-write the URL                        OK rewrite-url="..."

        const char *statusNote = reply.notes.findFirst("status");
        const char *urlNote = reply.notes.findFirst("url");

        if (urlNote != NULL) {
            // HTTP protocol redirect to be done.

            // TODO: change default redirect status for appropriate requests
            // Squid defaults to 302 status for now for better compatibility with old clients.
            // HTTP/1.0 client should get 302 (Http::scFound)
            // HTTP/1.1 client contacting reverse-proxy should get 307 (Http::scTemporaryRedirect)
            // HTTP/1.1 client being diverted by forward-proxy should get 303 (Http::scSeeOther)
            Http::StatusCode status = Http::scFound;
            if (statusNote != NULL) {
                const char * result = statusNote;
                status = static_cast<Http::StatusCode>(atoi(result));
            }

            if (status == Http::scMovedPermanently
                    || status == Http::scFound
                    || status == Http::scSeeOther
                    || status == Http::scPermanentRedirect
                    || status == Http::scTemporaryRedirect) {
                http->redirect.status = status;
                http->redirect.location = xstrdup(urlNote);
                // TODO: validate the URL produced here is RFC 2616 compliant absolute URI
            } else {
                debugs(85, DBG_CRITICAL, "ERROR: URL-rewrite produces invalid " << status << " redirect Location: " << urlNote);
            }
        } else {
            // URL-rewrite wanted. Ew.
            urlNote = reply.notes.findFirst("rewrite-url");

            // prevent broken helpers causing too much damage. If old URL == new URL skip the re-write.
            if (urlNote != NULL && strcmp(urlNote, http->uri)) {
                AnyP::Uri tmpUrl;
                if (tmpUrl.parse(old_request->method, urlNote)) {
                    HttpRequest *new_request = old_request->clone();
                    new_request->url = tmpUrl;
                    debugs(61, 2, "URL-rewriter diverts URL from " << old_request->effectiveRequestUri() << " to " << new_request->effectiveRequestUri());

                    // update the new request to flag the re-writing was done on it
                    new_request->flags.redirected = true;

                    // unlink bodypipe from the old request. Not needed there any longer.
                    if (old_request->body_pipe != NULL) {
                        old_request->body_pipe = NULL;
                        debugs(61,2, HERE << "URL-rewriter diverts body_pipe " << new_request->body_pipe <<
                               " from request " << old_request << " to " << new_request);
                    }

                    http->resetRequest(new_request);
                    old_request = nullptr;
                } else {
                    debugs(85, DBG_CRITICAL, "ERROR: URL-rewrite produces invalid request: " <<
                           old_request->method << " " << urlNote << " " << old_request->http_ver);
                }
            }
        }
    }
    break;
    }

    /* FIXME PIPELINE: This is innacurate during pipelining */

    if (http->getConn() != NULL && Comm::IsConnOpen(http->getConn()->clientConnection))
        fd_note(http->getConn()->clientConnection->fd, http->uri);

    assert(http->uri);

    http->doCallouts();
}

/**
 * This method handles the different replies from StoreID helper.
 */
void
ClientRequestContext::clientStoreIdDone(const Helper::Reply &reply)
{
    HttpRequest *old_request = http->request;
    debugs(85, 5, "'" << http->uri << "' result=" << reply);
    assert(store_id_state == REDIRECT_PENDING);
    store_id_state = REDIRECT_DONE;

    // Put helper response Notes into the transaction state record (ALE) eventually
    // do it early to ensure that no matter what the outcome the notes are present.
    if (http->al)
        http->al->syncNotes(old_request);

    UpdateRequestNotes(http->getConn(), *old_request, reply.notes);

    switch (reply.result) {
    case Helper::Unknown:
    case Helper::TT:
        // Handler in redirect.cc should have already mapped Unknown
        // IF it contained valid entry for the old helper protocol
        debugs(85, DBG_IMPORTANT, "ERROR: storeID helper returned invalid result code. Wrong helper? " << reply);
        break;

    case Helper::TimedOut:
    // Timeouts for storeID are not implemented
    case Helper::BrokenHelper:
        debugs(85, DBG_IMPORTANT, "ERROR: storeID helper: " << reply);
        break;

    case Helper::Error:
        // no change to be done.
        break;

    case Helper::Okay: {
        const char *urlNote = reply.notes.findFirst("store-id");

        // prevent broken helpers causing too much damage. If old URL == new URL skip the re-write.
        if (urlNote != NULL && strcmp(urlNote, http->uri) ) {
            // Debug section required for some very specific cases.
            debugs(85, 9, "Setting storeID with: " << urlNote );
            http->request->store_id = urlNote;
            http->store_id = urlNote;
        }
    }
    break;
    }

    http->doCallouts();
}

/** Test cache allow/deny configuration
 *  Sets flags.cachable=1 if caching is not denied.
 */
void
ClientRequestContext::checkNoCache()
{
    if (Config.accessList.noCache) {
        acl_checklist = clientAclChecklistCreate(Config.accessList.noCache, http);
        acl_checklist->nonBlockingCheck(checkNoCacheDoneWrapper, this);
    } else {
        /* unless otherwise specified, we try to cache. */
        checkNoCacheDone(ACCESS_ALLOWED);
    }
}

static void
checkNoCacheDoneWrapper(allow_t answer, void *data)
{
    ClientRequestContext *calloutContext = (ClientRequestContext *) data;

    if (!calloutContext->httpStateIsValid())
        return;

    calloutContext->checkNoCacheDone(answer);
}

void
ClientRequestContext::checkNoCacheDone(const allow_t &answer)
{
    acl_checklist = NULL;
    if (answer.denied()) {
        http->request->flags.noCache = true; // do not read reply from cache
        http->request->flags.cachable = false; // do not store reply into cache
    }
    http->doCallouts();
}

#if USE_OPENSSL
bool
ClientRequestContext::sslBumpAccessCheck()
{
    if (!http->getConn()) {
        http->al->ssl.bumpMode = Ssl::bumpEnd; // SslBump does not apply; log -
        return false;
    }

    const Ssl::BumpMode bumpMode = http->getConn()->sslBumpMode;
    if (http->request->flags.forceTunnel) {
        debugs(85, 5, "not needed; already decided to tunnel " << http->getConn());
        if (bumpMode != Ssl::bumpEnd)
            http->al->ssl.bumpMode = bumpMode; // inherited from bumped connection
        return false;
    }

    // If SSL connection tunneling or bumping decision has been made, obey it.
    if (bumpMode != Ssl::bumpEnd) {
        debugs(85, 5, HERE << "SslBump already decided (" << bumpMode <<
               "), " << "ignoring ssl_bump for " << http->getConn());

        // We need the following "if" for transparently bumped TLS connection,
        // because in this case we are running ssl_bump access list before
        // the doCallouts runs. It can be removed after the bug #4340 fixed.
        // We do not want to proceed to bumping steps:
        //  - if the TLS connection with the client is already established
        //    because we are accepting normal HTTP requests on TLS port,
        //    or because of the client-first bumping mode
        //  - When the bumping is already started
        if (!http->getConn()->switchedToHttps() &&
                !http->getConn()->serverBump())
            http->sslBumpNeed(bumpMode); // for processRequest() to bump if needed and not already bumped
        http->al->ssl.bumpMode = bumpMode; // inherited from bumped connection
        return false;
    }

    // If we have not decided yet, decide whether to bump now.

    // Bumping here can only start with a CONNECT request on a bumping port
    // (bumping of intercepted SSL conns is decided before we get 1st request).
    // We also do not bump redirected CONNECT requests.
    if (http->request->method != Http::METHOD_CONNECT || http->redirect.status ||
            !Config.accessList.ssl_bump ||
            !http->getConn()->port->flags.tunnelSslBumping) {
        http->al->ssl.bumpMode = Ssl::bumpEnd; // SslBump does not apply; log -
        debugs(85, 5, HERE << "cannot SslBump this request");
        return false;
    }

    // Do not bump during authentication: clients would not proxy-authenticate
    // if we delay a 407 response and respond with 200 OK to CONNECT.
    if (error && error->httpStatus == Http::scProxyAuthenticationRequired) {
        http->al->ssl.bumpMode = Ssl::bumpEnd; // SslBump does not apply; log -
        debugs(85, 5, HERE << "no SslBump during proxy authentication");
        return false;
    }

    if (error) {
        debugs(85, 5, "SslBump applies. Force bump action on error " << errorTypeName(error->type));
        http->sslBumpNeed(Ssl::bumpBump);
        http->al->ssl.bumpMode = Ssl::bumpBump;
        return false;
    }

    debugs(85, 5, HERE << "SslBump possible, checking ACL");

    ACLFilledChecklist *aclChecklist = clientAclChecklistCreate(Config.accessList.ssl_bump, http);
    aclChecklist->nonBlockingCheck(sslBumpAccessCheckDoneWrapper, this);
    return true;
}

/**
 * A wrapper function to use the ClientRequestContext::sslBumpAccessCheckDone method
 * as ACLFilledChecklist callback
 */
static void
sslBumpAccessCheckDoneWrapper(allow_t answer, void *data)
{
    ClientRequestContext *calloutContext = static_cast<ClientRequestContext *>(data);

    if (!calloutContext->httpStateIsValid())
        return;
    calloutContext->sslBumpAccessCheckDone(answer);
}

void
ClientRequestContext::sslBumpAccessCheckDone(const allow_t &answer)
{
    if (!httpStateIsValid())
        return;

    const Ssl::BumpMode bumpMode = answer.allowed() ?
                                   static_cast<Ssl::BumpMode>(answer.kind) : Ssl::bumpSplice;
    http->sslBumpNeed(bumpMode); // for processRequest() to bump if needed
    http->al->ssl.bumpMode = bumpMode; // for logging

    if (bumpMode == Ssl::bumpTerminate) {
        const Comm::ConnectionPointer clientConn = http->getConn() ? http->getConn()->clientConnection : nullptr;
        if (Comm::IsConnOpen(clientConn)) {
            debugs(85, 3, "closing after Ssl::bumpTerminate ");
            clientConn->close();
        }
        return;
    }

    http->doCallouts();
}
#endif

/*
 * Identify requests that do not go through the store and client side stream
 * and forward them to the appropriate location. All other requests, request
 * them.
 */
void
ClientHttpRequest::processRequest()
{
    debugs(85, 4, request->method << ' ' << uri);

    const bool untouchedConnect = request->method == Http::METHOD_CONNECT && !redirect.status;

#if USE_OPENSSL
    if (untouchedConnect && sslBumpNeeded()) {
        assert(!request->flags.forceTunnel);
        sslBumpStart();
        return;
    }
#endif

    if (untouchedConnect || request->flags.forceTunnel) {
        getConn()->stopReading(); // tunnels read for themselves
        tunnelStart(this);
        return;
    }

    httpStart();
}

void
ClientHttpRequest::httpStart()
{
    PROF_start(httpStart);
    // XXX: Re-initializes rather than updates. Should not be needed at all.
    logType.update(LOG_TAG_NONE);
    debugs(85, 4, logType.c_str() << " for '" << uri << "'");

    /* no one should have touched this */
    assert(out.offset == 0);
    /* Use the Stream Luke */
    clientStreamNode *node = (clientStreamNode *)client_stream.tail->data;
    clientStreamRead(node, this, node->readBuffer);
    PROF_stop(httpStart);
}

#if USE_OPENSSL

void
ClientHttpRequest::sslBumpNeed(Ssl::BumpMode mode)
{
    debugs(83, 3, HERE << "sslBump required: "<< Ssl::bumpMode(mode));
    sslBumpNeed_ = mode;
}

// called when comm_write has completed
static void
SslBumpEstablish(const Comm::ConnectionPointer &, char *, size_t, Comm::Flag errflag, int, void *data)
{
    ClientHttpRequest *r = static_cast<ClientHttpRequest*>(data);
    debugs(85, 5, HERE << "responded to CONNECT: " << r << " ? " << errflag);

    assert(r && cbdataReferenceValid(r));
    r->sslBumpEstablish(errflag);
}

void
ClientHttpRequest::sslBumpEstablish(Comm::Flag errflag)
{
    // Bail out quickly on Comm::ERR_CLOSING - close handlers will tidy up
    if (errflag == Comm::ERR_CLOSING)
        return;

    if (errflag) {
        debugs(85, 3, HERE << "CONNECT response failure in SslBump: " << errflag);
        getConn()->clientConnection->close();
        return;
    }

    // We lack HttpReply which logRequest() uses to log the status code.
    // TODO: Use HttpReply instead of the "200 Connection established" string.
    al->http.code = 200;

#if USE_AUTH
    // Preserve authentication info for the ssl-bumped request
    if (request->auth_user_request != NULL)
        getConn()->setAuth(request->auth_user_request, "SSL-bumped CONNECT");
#endif

    assert(sslBumpNeeded());
    getConn()->switchToHttps(request, sslBumpNeed_);
}

void
ClientHttpRequest::sslBumpStart()
{
    debugs(85, 5, HERE << "Confirming " << Ssl::bumpMode(sslBumpNeed_) <<
           "-bumped CONNECT tunnel on FD " << getConn()->clientConnection);
    getConn()->sslBumpMode = sslBumpNeed_;

    AsyncCall::Pointer bumpCall = commCbCall(85, 5, "ClientSocketContext::sslBumpEstablish",
                                  CommIoCbPtrFun(&SslBumpEstablish, this));

    if (request->flags.interceptTproxy || request->flags.intercepted) {
        CommIoCbParams &params = GetCommParams<CommIoCbParams>(bumpCall);
        params.flag = Comm::OK;
        params.conn = getConn()->clientConnection;
        ScheduleCallHere(bumpCall);
        return;
    }

    // send an HTTP 200 response to kick client SSL negotiation
    // TODO: Unify with tunnel.cc and add a Server(?) header
    static const char *const conn_established = "HTTP/1.1 200 Connection established\r\n\r\n";
    Comm::Write(getConn()->clientConnection, conn_established, strlen(conn_established), bumpCall, NULL);
}

#endif

bool
ClientHttpRequest::gotEnough() const
{
    /** TODO: should be querying the stream. */
    int64_t contentLength =
        memObject()->getReply()->bodySize(request->method);
    assert(contentLength >= 0);

    if (out.offset < contentLength)
        return false;

    return true;
}

void
ClientHttpRequest::storeEntry(StoreEntry *newEntry)
{
    entry_ = newEntry;
}

void
ClientHttpRequest::loggingEntry(StoreEntry *newEntry)
{
    if (loggingEntry_)
        loggingEntry_->unlock("ClientHttpRequest::loggingEntry");

    loggingEntry_ = newEntry;

    if (loggingEntry_)
        loggingEntry_->lock("ClientHttpRequest::loggingEntry");
}

void
ClientHttpRequest::initRequest(HttpRequest *aRequest)
{
    assignRequest(aRequest);
    if (const auto csd = getConn()) {
        if (!csd->notes()->empty())
            request->notes()->appendNewOnly(csd->notes().getRaw());
    }
    // al is created in the constructor
    assert(al);
    if (!al->request) {
        al->request = request;
        HTTPMSGLOCK(al->request);
        al->syncNotes(request);
    }
}

void
ClientHttpRequest::resetRequest(HttpRequest *newRequest)
{
    assert(request != newRequest);
    clearRequest();
    assignRequest(newRequest);
    xfree(uri);
    uri = SBufToCstring(request->effectiveRequestUri());
}

void
ClientHttpRequest::assignRequest(HttpRequest *newRequest)
{
    assert(newRequest);
    assert(!request);
    const_cast<HttpRequest *&>(request) = newRequest;
    HTTPMSGLOCK(request);
    setLogUriToRequestUri();
}

void
ClientHttpRequest::clearRequest()
{
    HttpRequest *oldRequest = request;
    HTTPMSGUNLOCK(oldRequest);
    const_cast<HttpRequest *&>(request) = nullptr;
    absorbLogUri(nullptr);
}

/*
 * doCallouts() - This function controls the order of "callout"
 * executions, including non-blocking access control checks, the
 * redirector, and ICAP.  Previously, these callouts were chained
 * together such that "clientAccessCheckDone()" would call
 * "clientRedirectStart()" and so on.
 *
 * The ClientRequestContext (aka calloutContext) class holds certain
 * state data for the callout/callback operations.  Previously
 * ClientHttpRequest would sort of hand off control to ClientRequestContext
 * for a short time.  ClientRequestContext would then delete itself
 * and pass control back to ClientHttpRequest when all callouts
 * were finished.
 *
 * This caused some problems for ICAP because we want to make the
 * ICAP callout after checking ACLs, but before checking the no_cache
 * list.  We can't stuff the ICAP state into the ClientRequestContext
 * class because we still need the ICAP state after ClientRequestContext
 * goes away.
 *
 * Note that ClientRequestContext is created before the first call
 * to doCallouts().
 *
 * If one of the callouts notices that ClientHttpRequest is no
 * longer valid, it should call cbdataReferenceDone() so that
 * ClientHttpRequest's reference count goes to zero and it will get
 * deleted.  ClientHttpRequest will then delete ClientRequestContext.
 *
 * Note that we set the _done flags here before actually starting
 * the callout.  This is strictly for convenience.
 */

tos_t aclMapTOS (acl_tos * head, ACLChecklist * ch);
Ip::NfMarkConfig aclFindNfMarkConfig (acl_nfmark * head, ACLChecklist * ch);

void
ClientHttpRequest::doCallouts()
{
    assert(calloutContext);

    if (!calloutContext->error) {
        // CVE-2009-0801: verify the Host: header is consistent with other known details.
        if (!calloutContext->host_header_verify_done) {
            debugs(83, 3, HERE << "Doing calloutContext->hostHeaderVerify()");
            calloutContext->host_header_verify_done = true;
            calloutContext->hostHeaderVerify();
            return;
        }

        if (!calloutContext->http_access_done) {
            debugs(83, 3, HERE << "Doing calloutContext->clientAccessCheck()");
            calloutContext->http_access_done = true;
            calloutContext->clientAccessCheck();
            return;
        }

#if USE_ADAPTATION
        if (!calloutContext->adaptation_acl_check_done) {
            calloutContext->adaptation_acl_check_done = true;
            if (Adaptation::AccessCheck::Start(
                        Adaptation::methodReqmod, Adaptation::pointPreCache,
                        request, NULL, calloutContext->http->al, this))
                return; // will call callback
        }
#endif

        if (!calloutContext->redirect_done) {
            calloutContext->redirect_done = true;

            if (Config.Program.redirect) {
                debugs(83, 3, HERE << "Doing calloutContext->clientRedirectStart()");
                calloutContext->redirect_state = REDIRECT_PENDING;
                calloutContext->clientRedirectStart();
                return;
            }
        }

        if (!calloutContext->adapted_http_access_done) {
            debugs(83, 3, HERE << "Doing calloutContext->clientAccessCheck2()");
            calloutContext->adapted_http_access_done = true;
            calloutContext->clientAccessCheck2();
            return;
        }

        if (!calloutContext->store_id_done) {
            calloutContext->store_id_done = true;

            if (Config.Program.store_id) {
                debugs(83, 3,"Doing calloutContext->clientStoreIdStart()");
                calloutContext->store_id_state = REDIRECT_PENDING;
                calloutContext->clientStoreIdStart();
                return;
            }
        }

        if (!calloutContext->interpreted_req_hdrs) {
            debugs(83, 3, HERE << "Doing clientInterpretRequestHeaders()");
            calloutContext->interpreted_req_hdrs = 1;
            clientInterpretRequestHeaders(this);
        }

        if (!calloutContext->no_cache_done) {
            calloutContext->no_cache_done = true;

            if (Config.accessList.noCache && request->flags.cachable) {
                debugs(83, 3, HERE << "Doing calloutContext->checkNoCache()");
                calloutContext->checkNoCache();
                return;
            }
        }
    } //  if !calloutContext->error

    // Set appropriate MARKs and CONNMARKs if needed.
    if (getConn() && Comm::IsConnOpen(getConn()->clientConnection)) {
        ACLFilledChecklist ch(nullptr, request, nullptr);
        ch.al = calloutContext->http->al;
        ch.src_addr = request->client_addr;
        ch.my_addr = request->my_addr;
        ch.syncAle(request, log_uri);

        if (!calloutContext->toClientMarkingDone) {
            calloutContext->toClientMarkingDone = true;
            tos_t tos = aclMapTOS(Ip::Qos::TheConfig.tosToClient, &ch);
            if (tos)
                Ip::Qos::setSockTos(getConn()->clientConnection, tos);

            const auto packetMark = aclFindNfMarkConfig(Ip::Qos::TheConfig.nfmarkToClient, &ch);
            if (!packetMark.isEmpty())
                Ip::Qos::setSockNfmark(getConn()->clientConnection, packetMark.mark);

            const auto connmark = aclFindNfMarkConfig(Ip::Qos::TheConfig.nfConnmarkToClient, &ch);
            if (!connmark.isEmpty())
                Ip::Qos::setNfConnmark(getConn()->clientConnection, Ip::Qos::dirAccepted, connmark);
        }
    }

#if USE_OPENSSL
    // Even with calloutContext->error, we call sslBumpAccessCheck() to decide
    // whether SslBump applies to this transaction. If it applies, we will
    // attempt to bump the client to serve the error.
    if (!calloutContext->sslBumpCheckDone) {
        calloutContext->sslBumpCheckDone = true;
        if (calloutContext->sslBumpAccessCheck())
            return;
        /* else no ssl bump required*/
    }
#endif

    if (calloutContext->error) {
        // XXX: prformance regression. c_str() reallocates
        SBuf storeUriBuf(request->storeId());
        const char *storeUri = storeUriBuf.c_str();
        StoreEntry *e = storeCreateEntry(storeUri, storeUri, request->flags, request->method);
#if USE_OPENSSL
        if (sslBumpNeeded()) {
            // We have to serve an error, so bump the client first.
            sslBumpNeed(Ssl::bumpClientFirst);
            // set final error but delay sending until we bump
            Ssl::ServerBump *srvBump = new Ssl::ServerBump(request, e, Ssl::bumpClientFirst);
            errorAppendEntry(e, calloutContext->error);
            calloutContext->error = NULL;
            getConn()->setServerBump(srvBump);
            e->unlock("ClientHttpRequest::doCallouts+sslBumpNeeded");
        } else
#endif
        {
            // send the error to the client now
            clientStreamNode *node = (clientStreamNode *)client_stream.tail->prev->data;
            clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
            assert (repContext);
            repContext->setReplyToStoreEntry(e, "immediate SslBump error");
            errorAppendEntry(e, calloutContext->error);
            calloutContext->error = NULL;
            if (calloutContext->readNextRequest && getConn())
                getConn()->flags.readMore = true; // resume any pipeline reads.
            node = (clientStreamNode *)client_stream.tail->data;
            clientStreamRead(node, this, node->readBuffer);
            e->unlock("ClientHttpRequest::doCallouts-sslBumpNeeded");
            return;
        }
    }

    cbdataReferenceDone(calloutContext->http);
    delete calloutContext;
    calloutContext = NULL;
#if HEADERS_LOG

    headersLog(0, 1, request->method, request);
#endif

    debugs(83, 3, HERE << "calling processRequest()");
    processRequest();

#if ICAP_CLIENT
    Adaptation::Icap::History::Pointer ih = request->icapHistory();
    if (ih != NULL)
        ih->logType = logType;
#endif
}

void
ClientHttpRequest::setLogUriToRequestUri()
{
    assert(request);
    const auto canonicalUri = request->canonicalCleanUrl();
    absorbLogUri(xstrndup(canonicalUri, MAX_URL));
}

void
ClientHttpRequest::setLogUriToRawUri(const char *rawUri, const HttpRequestMethod &method)
{
    assert(rawUri);
    // Should(!request);

    // TODO: SBuf() performance regression, fix by converting rawUri to SBuf
    char *canonicalUri = urlCanonicalCleanWithoutRequest(SBuf(rawUri), method, AnyP::UriScheme());

    absorbLogUri(AnyP::Uri::cleanup(canonicalUri));

    char *cleanedRawUri = AnyP::Uri::cleanup(rawUri);
    al->setVirginUrlForMissingRequest(SBuf(cleanedRawUri));
    xfree(cleanedRawUri);
}

void
ClientHttpRequest::absorbLogUri(char *aUri)
{
    xfree(log_uri);
    const_cast<char *&>(log_uri) = aUri;
}

void
ClientHttpRequest::setErrorUri(const char *aUri)
{
    assert(!uri);
    assert(aUri);
    // Should(!request);

    uri = xstrdup(aUri);
    // TODO: SBuf() performance regression, fix by converting setErrorUri() parameter to SBuf
    const SBuf errorUri(aUri);
    const auto canonicalUri = urlCanonicalCleanWithoutRequest(errorUri, HttpRequestMethod(), AnyP::UriScheme());
    absorbLogUri(xstrndup(canonicalUri, MAX_URL));

    al->setVirginUrlForMissingRequest(errorUri);
}

#if USE_ADAPTATION
/// Initiate an asynchronous adaptation transaction which will call us back.
void
ClientHttpRequest::startAdaptation(const Adaptation::ServiceGroupPointer &g)
{
    debugs(85, 3, HERE << "adaptation needed for " << this);
    assert(!virginHeadSource);
    assert(!adaptedBodySource);
    virginHeadSource = initiateAdaptation(
                           new Adaptation::Iterator(request, NULL, al, g));

    // we could try to guess whether we can bypass this adaptation
    // initiation failure, but it should not really happen
    Must(initiated(virginHeadSource));
}

void
ClientHttpRequest::noteAdaptationAnswer(const Adaptation::Answer &answer)
{
    assert(cbdataReferenceValid(this));     // indicates bug
    clearAdaptation(virginHeadSource);
    assert(!adaptedBodySource);

    switch (answer.kind) {
    case Adaptation::Answer::akForward:
        handleAdaptedHeader(const_cast<Http::Message*>(answer.message.getRaw()));
        break;

    case Adaptation::Answer::akBlock:
        handleAdaptationBlock(answer);
        break;

    case Adaptation::Answer::akError:
        handleAdaptationFailure(ERR_DETAIL_CLT_REQMOD_ABORT, !answer.final);
        break;
    }
}

void
ClientHttpRequest::handleAdaptedHeader(Http::Message *msg)
{
    assert(msg);

    if (HttpRequest *new_req = dynamic_cast<HttpRequest*>(msg)) {
        // update the new message to flag whether URL re-writing was done on it
        if (request->effectiveRequestUri() != new_req->effectiveRequestUri())
            new_req->flags.redirected = true;
        resetRequest(new_req);
        assert(request->method.id());
    } else if (HttpReply *new_rep = dynamic_cast<HttpReply*>(msg)) {
        debugs(85,3,HERE << "REQMOD reply is HTTP reply");

        // subscribe to receive reply body
        if (new_rep->body_pipe != NULL) {
            adaptedBodySource = new_rep->body_pipe;
            int consumer_ok = adaptedBodySource->setConsumerIfNotLate(this);
            assert(consumer_ok);
        }

        clientStreamNode *node = (clientStreamNode *)client_stream.tail->prev->data;
        clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
        assert(repContext);
        repContext->createStoreEntry(request->method, request->flags);

        request_satisfaction_mode = true;
        request_satisfaction_offset = 0;
        storeEntry()->replaceHttpReply(new_rep);
        storeEntry()->timestampsSet();

        if (!adaptedBodySource) // no body
            storeEntry()->complete();
        clientGetMoreData(node, this);
    }

    // we are done with getting headers (but may be receiving body)
    clearAdaptation(virginHeadSource);

    if (!request_satisfaction_mode)
        doCallouts();
}

void
ClientHttpRequest::handleAdaptationBlock(const Adaptation::Answer &answer)
{
    request->detailError(ERR_ACCESS_DENIED, ERR_DETAIL_REQMOD_BLOCK);
    AclMatchedName = answer.ruleId.termedBuf();
    assert(calloutContext);
    calloutContext->clientAccessCheckDone(ACCESS_DENIED);
    AclMatchedName = NULL;
}

void
ClientHttpRequest::resumeBodyStorage()
{
    if (!adaptedBodySource)
        return;

    noteMoreBodyDataAvailable(adaptedBodySource);
}

void
ClientHttpRequest::noteMoreBodyDataAvailable(BodyPipe::Pointer)
{
    assert(request_satisfaction_mode);
    assert(adaptedBodySource != NULL);

    if (size_t contentSize = adaptedBodySource->buf().contentSize()) {
        const size_t spaceAvailable = storeEntry()->bytesWanted(Range<size_t>(0,contentSize));

        if (spaceAvailable < contentSize ) {
            // No or partial body data consuming
            typedef NullaryMemFunT<ClientHttpRequest> Dialer;
            AsyncCall::Pointer call = asyncCall(93, 5, "ClientHttpRequest::resumeBodyStorage",
                                                Dialer(this, &ClientHttpRequest::resumeBodyStorage));
            storeEntry()->deferProducer(call);
        }

        if (!spaceAvailable)
            return;

        if (spaceAvailable < contentSize )
            contentSize = spaceAvailable;

        BodyPipeCheckout bpc(*adaptedBodySource);
        const StoreIOBuffer ioBuf(&bpc.buf, request_satisfaction_offset, contentSize);
        storeEntry()->write(ioBuf);
        // assume StoreEntry::write() writes the entire ioBuf
        request_satisfaction_offset += ioBuf.length;
        bpc.buf.consume(contentSize);
        bpc.checkIn();
    }

    if (adaptedBodySource->exhausted())
        endRequestSatisfaction();
    // else wait for more body data
}

void
ClientHttpRequest::noteBodyProductionEnded(BodyPipe::Pointer)
{
    assert(!virginHeadSource);
    // should we end request satisfaction now?
    if (adaptedBodySource != NULL && adaptedBodySource->exhausted())
        endRequestSatisfaction();
}

void
ClientHttpRequest::endRequestSatisfaction()
{
    debugs(85,4, HERE << this << " ends request satisfaction");
    assert(request_satisfaction_mode);
    stopConsumingFrom(adaptedBodySource);

    // TODO: anything else needed to end store entry formation correctly?
    storeEntry()->complete();
}

void
ClientHttpRequest::noteBodyProducerAborted(BodyPipe::Pointer)
{
    assert(!virginHeadSource);
    stopConsumingFrom(adaptedBodySource);

    debugs(85,3, HERE << "REQMOD body production failed");
    if (request_satisfaction_mode) { // too late to recover or serve an error
        request->detailError(ERR_ICAP_FAILURE, ERR_DETAIL_CLT_REQMOD_RESP_BODY);
        const Comm::ConnectionPointer c = getConn()->clientConnection;
        Must(Comm::IsConnOpen(c));
        c->close(); // drastic, but we may be writing a response already
    } else {
        handleAdaptationFailure(ERR_DETAIL_CLT_REQMOD_REQ_BODY);
    }
}

void
ClientHttpRequest::handleAdaptationFailure(int errDetail, bool bypassable)
{
    debugs(85,3, HERE << "handleAdaptationFailure(" << bypassable << ")");

    const bool usedStore = storeEntry() && !storeEntry()->isEmpty();
    const bool usedPipe = request->body_pipe != NULL &&
                          request->body_pipe->consumedSize() > 0;

    if (bypassable && !usedStore && !usedPipe) {
        debugs(85,3, HERE << "ICAP REQMOD callout failed, bypassing: " << calloutContext);
        if (calloutContext)
            doCallouts();
        return;
    }

    debugs(85,3, HERE << "ICAP REQMOD callout failed, responding with error");

    clientStreamNode *node = (clientStreamNode *)client_stream.tail->prev->data;
    clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
    assert(repContext);

    calloutsError(ERR_ICAP_FAILURE, errDetail);

    if (calloutContext)
        doCallouts();
}

void
ClientHttpRequest::callException(const std::exception &ex)
{
    if (const auto clientConn = getConn() ? getConn()->clientConnection : nullptr) {
        if (Comm::IsConnOpen(clientConn)) {
            debugs(85, 3, "closing after exception: " << ex.what());
            clientConn->close(); // initiate orderly top-to-bottom cleanup
            return;
        }
    }
    debugs(85, DBG_IMPORTANT, "ClientHttpRequest exception without connection. Ignoring " << ex.what());
    // XXX: Normally, we mustStop() but we cannot do that here because it is
    // likely to leave Http::Stream and ConnStateData with a dangling http
    // pointer. See r13480 or XXX in Http::Stream class description.
}
#endif

// XXX: modify and use with ClientRequestContext::clientAccessCheckDone too.
void
ClientHttpRequest::calloutsError(const err_type error, const int errDetail)
{
    // The original author of the code also wanted to pass an errno to
    // setReplyToError, but it seems unlikely that the errno reflects the
    // true cause of the error at this point, so I did not pass it.
    if (calloutContext) {
        Ip::Address noAddr;
        noAddr.setNoAddr();
        ConnStateData * c = getConn();
        calloutContext->error = clientBuildError(error, Http::scInternalServerError,
                                NULL,
                                c != NULL ? c->clientConnection->remote : noAddr,
                                request,
                                al
                                                );
#if USE_AUTH
        calloutContext->error->auth_user_request =
            c != NULL && c->getAuth() != NULL ? c->getAuth() : request->auth_user_request;
#endif
        calloutContext->error->detailError(errDetail);
        calloutContext->readNextRequest = true;
        if (c != NULL)
            c->expectNoForwarding();
    }
    //else if(calloutContext == NULL) is it possible?
}