src/pconn.cc

   1
   2 /*
   3  * $Id: pconn.cc,v 1.33 2002/10/13 20:35:02 robertc Exp $
   4  *
   5  * DEBUG: section 48    Persistent Connections
   6  * AUTHOR: Duane Wessels
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "Store.h"
  38
  39 struct _pconn {
  40     hash_link hash;             /* must be first */
  41     int *fds;
  42     int nfds_alloc;
  43     int nfds;
  44 };
  45 typedef struct _pconn pconn;
  46
  47 #define PCONN_FDS_SZ    8       /* pconn set size, increase for better memcache hit rate */
  48 #define PCONN_HIST_SZ (1<<16)
  49 int client_pconn_hist[PCONN_HIST_SZ];
  50 int server_pconn_hist[PCONN_HIST_SZ];
  51
  52 static PF pconnRead;
  53 static PF pconnTimeout;
  54 static const char *pconnKey(const char *host, u_short port);
  55 static hash_table *table = NULL;
  56 static struct _pconn *pconnNew(const char *key);
  57 static void pconnDelete(struct _pconn *p);
  58 static void pconnRemoveFD(struct _pconn *p, int fd);
  59 static OBJH pconnHistDump;
  60 static MemPool *pconn_fds_pool = NULL;
  61 CBDATA_TYPE(pconn);
  62
  63
  64
  65 static const char *
  66 pconnKey(const char *host, u_short port)
  67 {
  68     LOCAL_ARRAY(char, buf, SQUIDHOSTNAMELEN + 10);
  69     snprintf(buf, SQUIDHOSTNAMELEN + 10, "%s.%d", host, (int) port);
  70     return buf;
  71 }
  72
  73 static struct _pconn *
  74 pconnNew(const char *key)
  75 {
  76     pconn *p;
  77     CBDATA_INIT_TYPE(pconn);
  78     p = cbdataAlloc(pconn);
  79     p->hash.key = xstrdup(key);
  80     p->nfds_alloc = PCONN_FDS_SZ;
  81     p->fds = (int *)memPoolAlloc(pconn_fds_pool);
  82     debug(48, 3) ("pconnNew: adding %s\n", hashKeyStr(&p->hash));
  83     hash_join(table, &p->hash);
  84     return p;
  85 }
  86
  87 static void
  88 pconnDelete(struct _pconn *p)
  89 {
  90     debug(48, 3) ("pconnDelete: deleting %s\n", hashKeyStr(&p->hash));
  91     hash_remove_link(table, (hash_link *) p);
  92     if (p->nfds_alloc == PCONN_FDS_SZ)
  93         memPoolFree(pconn_fds_pool, p->fds);
  94     else
  95         xfree(p->fds);
  96     xfree(p->hash.key);
  97     cbdataFree(p);
  98 }
  99
 100 static void
 101 pconnRemoveFD(struct _pconn *p, int fd)
 102 {
 103     int i;
 104     for (i = 0; i < p->nfds; i++) {
 105         if (p->fds[i] == fd)
 106             break;
 107     }
 108     assert(i < p->nfds);
 109     debug(48, 3) ("pconnRemoveFD: found FD %d at index %d\n", fd, i);
 110     for (; i < p->nfds - 1; i++)
 111         p->fds[i] = p->fds[i + 1];
 112     if (--p->nfds == 0)
 113         pconnDelete(p);
 114 }
 115
 116 static void
 117 pconnTimeout(int fd, void *data)
 118 {
 119     struct _pconn *p = (_pconn *)data;
 120     assert(table != NULL);
 121     debug(48, 3) ("pconnTimeout: FD %d %s\n", fd, hashKeyStr(&p->hash));
 122     pconnRemoveFD(p, fd);
 123     comm_close(fd);
 124 }
 125
 126 static void
 127 pconnRead(int fd, void *data)
 128 {
 129     LOCAL_ARRAY(char, buf, 256);
 130     struct _pconn *p = (_pconn *)data;
 131     int n;
 132     assert(table != NULL);
 133     statCounter.syscalls.sock.reads++;
 134     n = FD_READ_METHOD(fd, buf, 256);
 135     debug(48, 3) ("pconnRead: %d bytes from FD %d, %s\n", n, fd,
 136         hashKeyStr(&p->hash));
 137     pconnRemoveFD(p, fd);
 138     comm_close(fd);
 139 }
 140
 141 static void
 142 pconnHistDump(StoreEntry * e)
 143 {
 144     int i;
 145     storeAppendPrintf(e,
 146         "Client-side persistent connection counts:\n"
 147         "\n"
 148         "\treq/\n"
 149         "\tconn      count\n"
 150         "\t----  ---------\n");
 151     for (i = 0; i < PCONN_HIST_SZ; i++) {
 152         if (client_pconn_hist[i] == 0)
 153             continue;
 154         storeAppendPrintf(e, "\t%4d  %9d\n", i, client_pconn_hist[i]);
 155     }
 156     storeAppendPrintf(e,
 157         "\n"
 158         "Server-side persistent connection counts:\n"
 159         "\n"
 160         "\treq/\n"
 161         "\tconn      count\n"
 162         "\t----  ---------\n");
 163     for (i = 0; i < PCONN_HIST_SZ; i++) {
 164         if (server_pconn_hist[i] == 0)
 165             continue;
 166         storeAppendPrintf(e, "\t%4d  %9d\n", i, server_pconn_hist[i]);
 167     }
 168 }
 169
 170 /* ========== PUBLIC FUNCTIONS ============================================ */
 171
 172
 173 void
 174 pconnInit(void)
 175 {
 176     int i;
 177     assert(table == NULL);
 178     table = hash_create((HASHCMP *) strcmp, 229, hash_string);
 179     for (i = 0; i < PCONN_HIST_SZ; i++) {
 180         client_pconn_hist[i] = 0;
 181         server_pconn_hist[i] = 0;
 182     }
 183     pconn_fds_pool = memPoolCreate("pconn_fds", PCONN_FDS_SZ * sizeof(int));
 184
 185     cachemgrRegister("pconn",
 186         "Persistent Connection Utilization Histograms",
 187         pconnHistDump, 0, 1);
 188     debug(48, 3) ("persistent connection module initialized\n");
 189 }
 190
 191 void
 192 pconnPush(int fd, const char *host, u_short port)
 193 {
 194     struct _pconn *p;
 195     int *old;
 196     LOCAL_ARRAY(char, key, SQUIDHOSTNAMELEN + 10);
 197     LOCAL_ARRAY(char, desc, FD_DESC_SZ);
 198     if (fdNFree() < (RESERVED_FD << 1)) {
 199         debug(48, 3) ("pconnPush: Not many unused FDs\n");
 200         comm_close(fd);
 201         return;
 202     } else if (shutting_down) {
 203         comm_close(fd);
 204         return;
 205     }
 206     assert(table != NULL);
 207     strcpy(key, pconnKey(host, port));
 208     p = (struct _pconn *) hash_lookup(table, key);
 209     if (p == NULL)
 210         p = pconnNew(key);
 211     if (p->nfds == p->nfds_alloc) {
 212         debug(48, 3) ("pconnPush: growing FD array\n");
 213         p->nfds_alloc <<= 1;
 214         old = p->fds;
 215         p->fds = (int *)xmalloc(p->nfds_alloc * sizeof(int));
 216         xmemcpy(p->fds, old, p->nfds * sizeof(int));
 217         if (p->nfds == PCONN_FDS_SZ)
 218             memPoolFree(pconn_fds_pool, old);
 219         else
 220             xfree(old);
 221     }
 222     p->fds[p->nfds++] = fd;
 223     commSetSelect(fd, COMM_SELECT_READ, pconnRead, p, 0);
 224     commSetTimeout(fd, Config.Timeout.pconn, pconnTimeout, p);
 225     snprintf(desc, FD_DESC_SZ, "%s idle connection", host);
 226     fd_note(fd, desc);
 227     debug(48, 3) ("pconnPush: pushed FD %d for %s\n", fd, key);
 228 }
 229
 230 int
 231 pconnPop(const char *host, u_short port)
 232 {
 233     struct _pconn *p;
 234     hash_link *hptr;
 235     int fd = -1;
 236     LOCAL_ARRAY(char, key, SQUIDHOSTNAMELEN + 10);
 237     assert(table != NULL);
 238     strcpy(key, pconnKey(host, port));
 239     hptr = (hash_link *)hash_lookup(table, key);
 240     if (hptr != NULL) {
 241         p = (struct _pconn *) hptr;
 242         assert(p->nfds > 0);
 243         fd = p->fds[0];
 244         pconnRemoveFD(p, fd);
 245         commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
 246         commSetTimeout(fd, -1, NULL, NULL);
 247     }
 248     return fd;
 249 }
 250
 251 void
 252 pconnHistCount(int what, int i)
 253 {
 254     if (i >= PCONN_HIST_SZ)
 255         i = PCONN_HIST_SZ - 1;
 256     /* what == 0 for client, 1 for server */
 257     if (what == 0)
 258         client_pconn_hist[i]++;
 259     else if (what == 1)
 260         server_pconn_hist[i]++;
 261     else
 262         assert(0);
 263 }