src/pconn.cc

   1
   2 /*
   3  * $Id: pconn.cc,v 1.31 2001/04/14 00:03:23 hno 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
  38 struct _pconn {
  39     hash_link hash;             /* must be first */
  40     int *fds;
  41     int nfds_alloc;
  42     int nfds;
  43 };
  44
  45 #define PCONN_FDS_SZ    8       /* pconn set size, increase for better memcache hit rate */
  46 #define PCONN_HIST_SZ (1<<16)
  47 int client_pconn_hist[PCONN_HIST_SZ];
  48 int server_pconn_hist[PCONN_HIST_SZ];
  49
  50 static PF pconnRead;
  51 static PF pconnTimeout;
  52 static const char *pconnKey(const char *host, u_short port);
  53 static hash_table *table = NULL;
  54 static struct _pconn *pconnNew(const char *key);
  55 static void pconnDelete(struct _pconn *p);
  56 static void pconnRemoveFD(struct _pconn *p, int fd);
  57 static OBJH pconnHistDump;
  58 static MemPool *pconn_data_pool = NULL;
  59 static MemPool *pconn_fds_pool = NULL;
  60
  61 static const char *
  62 pconnKey(const char *host, u_short port)
  63 {
  64     LOCAL_ARRAY(char, buf, SQUIDHOSTNAMELEN + 10);
  65     snprintf(buf, SQUIDHOSTNAMELEN + 10, "%s.%d", host, (int) port);
  66     return buf;
  67 }
  68
  69 static struct _pconn *
  70 pconnNew(const char *key)
  71 {
  72     struct _pconn *p = memPoolAlloc(pconn_data_pool);
  73     p->hash.key = xstrdup(key);
  74     p->nfds_alloc = PCONN_FDS_SZ;
  75     p->fds = memPoolAlloc(pconn_fds_pool);
  76     debug(48, 3) ("pconnNew: adding %s\n", hashKeyStr(&p->hash));
  77     hash_join(table, &p->hash);
  78     return p;
  79 }
  80
  81 static void
  82 pconnDelete(struct _pconn *p)
  83 {
  84     debug(48, 3) ("pconnDelete: deleting %s\n", hashKeyStr(&p->hash));
  85     hash_remove_link(table, (hash_link *) p);
  86     if (p->nfds_alloc == PCONN_FDS_SZ)
  87         memPoolFree(pconn_fds_pool, p->fds);
  88     else
  89         xfree(p->fds);
  90     xfree(p->hash.key);
  91     memPoolFree(pconn_data_pool, p);
  92 }
  93
  94 static void
  95 pconnRemoveFD(struct _pconn *p, int fd)
  96 {
  97     int i;
  98     for (i = 0; i < p->nfds; i++) {
  99         if (p->fds[i] == fd)
 100             break;
 101     }
 102     assert(i < p->nfds);
 103     debug(48, 3) ("pconnRemoveFD: found FD %d at index %d\n", fd, i);
 104     for (; i < p->nfds - 1; i++)
 105         p->fds[i] = p->fds[i + 1];
 106     if (--p->nfds == 0)
 107         pconnDelete(p);
 108 }
 109
 110 static void
 111 pconnTimeout(int fd, void *data)
 112 {
 113     struct _pconn *p = data;
 114     assert(table != NULL);
 115     debug(48, 3) ("pconnTimeout: FD %d %s\n", fd, hashKeyStr(&p->hash));
 116     pconnRemoveFD(p, fd);
 117     comm_close(fd);
 118 }
 119
 120 static void
 121 pconnRead(int fd, void *data)
 122 {
 123     LOCAL_ARRAY(char, buf, 256);
 124     struct _pconn *p = data;
 125     int n;
 126     assert(table != NULL);
 127     statCounter.syscalls.sock.reads++;
 128     n = FD_READ_METHOD(fd, buf, 256);
 129     debug(48, 3) ("pconnRead: %d bytes from FD %d, %s\n", n, fd,
 130         hashKeyStr(&p->hash));
 131     pconnRemoveFD(p, fd);
 132     comm_close(fd);
 133 }
 134
 135 static void
 136 pconnHistDump(StoreEntry * e)
 137 {
 138     int i;
 139     storeAppendPrintf(e,
 140         "Client-side persistent connection counts:\n"
 141         "\n"
 142         "\treq/\n"
 143         "\tconn      count\n"
 144         "\t----  ---------\n");
 145     for (i = 0; i < PCONN_HIST_SZ; i++) {
 146         if (client_pconn_hist[i] == 0)
 147             continue;
 148         storeAppendPrintf(e, "\t%4d  %9d\n", i, client_pconn_hist[i]);
 149     }
 150     storeAppendPrintf(e,
 151         "\n"
 152         "Server-side persistent connection counts:\n"
 153         "\n"
 154         "\treq/\n"
 155         "\tconn      count\n"
 156         "\t----  ---------\n");
 157     for (i = 0; i < PCONN_HIST_SZ; i++) {
 158         if (server_pconn_hist[i] == 0)
 159             continue;
 160         storeAppendPrintf(e, "\t%4d  %9d\n", i, server_pconn_hist[i]);
 161     }
 162 }
 163
 164 /* ========== PUBLIC FUNCTIONS ============================================ */
 165
 166
 167 void
 168 pconnInit(void)
 169 {
 170     int i;
 171     assert(table == NULL);
 172     table = hash_create((HASHCMP *) strcmp, 229, hash_string);
 173     for (i = 0; i < PCONN_HIST_SZ; i++) {
 174         client_pconn_hist[i] = 0;
 175         server_pconn_hist[i] = 0;
 176     }
 177     pconn_data_pool = memPoolCreate("pconn_data", sizeof(struct _pconn));
 178     pconn_fds_pool = memPoolCreate("pconn_fds", PCONN_FDS_SZ * sizeof(int));
 179
 180     cachemgrRegister("pconn",
 181         "Persistent Connection Utilization Histograms",
 182         pconnHistDump, 0, 1);
 183     debug(48, 3) ("persistent connection module initialized\n");
 184 }
 185
 186 void
 187 pconnPush(int fd, const char *host, u_short port)
 188 {
 189     struct _pconn *p;
 190     int *old;
 191     LOCAL_ARRAY(char, key, SQUIDHOSTNAMELEN + 10);
 192     LOCAL_ARRAY(char, desc, FD_DESC_SZ);
 193     if (fdNFree() < (RESERVED_FD << 1)) {
 194         debug(48, 3) ("pconnPush: Not many unused FDs\n");
 195         comm_close(fd);
 196         return;
 197     } else if (shutting_down) {
 198         comm_close(fd);
 199         return;
 200     }
 201     assert(table != NULL);
 202     strcpy(key, pconnKey(host, port));
 203     p = (struct _pconn *) hash_lookup(table, key);
 204     if (p == NULL)
 205         p = pconnNew(key);
 206     if (p->nfds == p->nfds_alloc) {
 207         debug(48, 3) ("pconnPush: growing FD array\n");
 208         p->nfds_alloc <<= 1;
 209         old = p->fds;
 210         p->fds = xmalloc(p->nfds_alloc * sizeof(int));
 211         xmemcpy(p->fds, old, p->nfds * sizeof(int));
 212         if (p->nfds == PCONN_FDS_SZ)
 213             memPoolFree(pconn_fds_pool, old);
 214         else
 215             xfree(old);
 216     }
 217     p->fds[p->nfds++] = fd;
 218     commSetSelect(fd, COMM_SELECT_READ, pconnRead, p, 0);
 219     commSetTimeout(fd, Config.Timeout.pconn, pconnTimeout, p);
 220     snprintf(desc, FD_DESC_SZ, "%s idle connection", host);
 221     fd_note(fd, desc);
 222     debug(48, 3) ("pconnPush: pushed FD %d for %s\n", fd, key);
 223 }
 224
 225 int
 226 pconnPop(const char *host, u_short port)
 227 {
 228     struct _pconn *p;
 229     hash_link *hptr;
 230     int fd = -1;
 231     LOCAL_ARRAY(char, key, SQUIDHOSTNAMELEN + 10);
 232     assert(table != NULL);
 233     strcpy(key, pconnKey(host, port));
 234     hptr = hash_lookup(table, key);
 235     if (hptr != NULL) {
 236         p = (struct _pconn *) hptr;
 237         assert(p->nfds > 0);
 238         fd = p->fds[0];
 239         pconnRemoveFD(p, fd);
 240         commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
 241         commSetTimeout(fd, -1, NULL, NULL);
 242     }
 243     return fd;
 244 }
 245
 246 void
 247 pconnHistCount(int what, int i)
 248 {
 249     if (i >= PCONN_HIST_SZ)
 250         i = PCONN_HIST_SZ - 1;
 251     /* what == 0 for client, 1 for server */
 252     if (what == 0)
 253         client_pconn_hist[i]++;
 254     else if (what == 1)
 255         server_pconn_hist[i]++;
 256     else
 257         assert(0);
 258 }