net/ipv4/ipvs/ip_vs_proto_tcp.c

   1 /*
   2  * ip_vs_proto_tcp.c:   TCP load balancing support for IPVS
   3  *
   4  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   5  *              Julian Anastasov <ja@ssi.bg>
   6  *
   7  *              This program is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  * Changes:
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/ip.h>
  18 #include <linux/tcp.h>                  /* for tcphdr */
  19 #include <net/ip.h>
  20 #include <net/tcp.h>                    /* for csum_tcpudp_magic */
  21 #include <linux/netfilter.h>
  22 #include <linux/netfilter_ipv4.h>
  23
  24 #include <net/ip_vs.h>
  25
  26
  27 static struct ip_vs_conn *
  28 tcp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  29                 const struct iphdr *iph, unsigned int proto_off, int inverse)
  30 {
  31         __be16 _ports[2], *pptr;
  32
  33         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  34         if (pptr == NULL)
  35                 return NULL;
  36
  37         if (likely(!inverse)) {
  38                 return ip_vs_conn_in_get(iph->protocol,
  39                                          iph->saddr, pptr[0],
  40                                          iph->daddr, pptr[1]);
  41         } else {
  42                 return ip_vs_conn_in_get(iph->protocol,
  43                                          iph->daddr, pptr[1],
  44                                          iph->saddr, pptr[0]);
  45         }
  46 }
  47
  48 static struct ip_vs_conn *
  49 tcp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  50                  const struct iphdr *iph, unsigned int proto_off, int inverse)
  51 {
  52         __be16 _ports[2], *pptr;
  53
  54         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  55         if (pptr == NULL)
  56                 return NULL;
  57
  58         if (likely(!inverse)) {
  59                 return ip_vs_conn_out_get(iph->protocol,
  60                                           iph->saddr, pptr[0],
  61                                           iph->daddr, pptr[1]);
  62         } else {
  63                 return ip_vs_conn_out_get(iph->protocol,
  64                                           iph->daddr, pptr[1],
  65                                           iph->saddr, pptr[0]);
  66         }
  67 }
  68
  69
  70 static int
  71 tcp_conn_schedule(struct sk_buff *skb,
  72                   struct ip_vs_protocol *pp,
  73                   int *verdict, struct ip_vs_conn **cpp)
  74 {
  75         struct ip_vs_service *svc;
  76         struct tcphdr _tcph, *th;
  77
  78         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
  79         if (th == NULL) {
  80                 *verdict = NF_DROP;
  81                 return 0;
  82         }
  83
  84         if (th->syn &&
  85             (svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
  86                                      ip_hdr(skb)->daddr, th->dest))) {
  87                 if (ip_vs_todrop()) {
  88                         /*
  89                          * It seems that we are very loaded.
  90                          * We have to drop this packet :(
  91                          */
  92                         ip_vs_service_put(svc);
  93                         *verdict = NF_DROP;
  94                         return 0;
  95                 }
  96
  97                 /*
  98                  * Let the virtual server select a real server for the
  99                  * incoming connection, and create a connection entry.
 100                  */
 101                 *cpp = ip_vs_schedule(svc, skb);
 102                 if (!*cpp) {
 103                         *verdict = ip_vs_leave(svc, skb, pp);
 104                         return 0;
 105                 }
 106                 ip_vs_service_put(svc);
 107         }
 108         return 1;
 109 }
 110
 111
 112 static inline void
 113 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
 114                      __be16 oldport, __be16 newport)
 115 {
 116         tcph->check =
 117                 csum_fold(ip_vs_check_diff4(oldip, newip,
 118                                  ip_vs_check_diff2(oldport, newport,
 119                                                 ~csum_unfold(tcph->check))));
 120 }
 121
 122
 123 static int
 124 tcp_snat_handler(struct sk_buff *skb,
 125                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 126 {
 127         struct tcphdr *tcph;
 128         const unsigned int tcphoff = ip_hdrlen(skb);
 129
 130         /* csum_check requires unshared skb */
 131         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 132                 return 0;
 133
 134         if (unlikely(cp->app != NULL)) {
 135                 /* Some checks before mangling */
 136                 if (pp->csum_check && !pp->csum_check(skb, pp))
 137                         return 0;
 138
 139                 /* Call application helper if needed */
 140                 if (!ip_vs_app_pkt_out(cp, skb))
 141                         return 0;
 142         }
 143
 144         tcph = (void *)ip_hdr(skb) + tcphoff;
 145         tcph->source = cp->vport;
 146
 147         /* Adjust TCP checksums */
 148         if (!cp->app) {
 149                 /* Only port and addr are changed, do fast csum update */
 150                 tcp_fast_csum_update(tcph, cp->daddr, cp->vaddr,
 151                                      cp->dport, cp->vport);
 152                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 153                         skb->ip_summed = CHECKSUM_NONE;
 154         } else {
 155                 /* full checksum calculation */
 156                 tcph->check = 0;
 157                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 158                 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
 159                                                 skb->len - tcphoff,
 160                                                 cp->protocol, skb->csum);
 161                 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
 162                           pp->name, tcph->check,
 163                           (char*)&(tcph->check) - (char*)tcph);
 164         }
 165         return 1;
 166 }
 167
 168
 169 static int
 170 tcp_dnat_handler(struct sk_buff *skb,
 171                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 172 {
 173         struct tcphdr *tcph;
 174         const unsigned int tcphoff = ip_hdrlen(skb);
 175
 176         /* csum_check requires unshared skb */
 177         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 178                 return 0;
 179
 180         if (unlikely(cp->app != NULL)) {
 181                 /* Some checks before mangling */
 182                 if (pp->csum_check && !pp->csum_check(skb, pp))
 183                         return 0;
 184
 185                 /*
 186                  *      Attempt ip_vs_app call.
 187                  *      It will fix ip_vs_conn and iph ack_seq stuff
 188                  */
 189                 if (!ip_vs_app_pkt_in(cp, skb))
 190                         return 0;
 191         }
 192
 193         tcph = (void *)ip_hdr(skb) + tcphoff;
 194         tcph->dest = cp->dport;
 195
 196         /*
 197          *      Adjust TCP checksums
 198          */
 199         if (!cp->app) {
 200                 /* Only port and addr are changed, do fast csum update */
 201                 tcp_fast_csum_update(tcph, cp->vaddr, cp->daddr,
 202                                      cp->vport, cp->dport);
 203                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 204                         skb->ip_summed = CHECKSUM_NONE;
 205         } else {
 206                 /* full checksum calculation */
 207                 tcph->check = 0;
 208                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 209                 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
 210                                                 skb->len - tcphoff,
 211                                                 cp->protocol, skb->csum);
 212                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 213         }
 214         return 1;
 215 }
 216
 217
 218 static int
 219 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
 220 {
 221         const unsigned int tcphoff = ip_hdrlen(skb);
 222
 223         switch (skb->ip_summed) {
 224         case CHECKSUM_NONE:
 225                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 226         case CHECKSUM_COMPLETE:
 227                 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 228                                       skb->len - tcphoff,
 229                                       ip_hdr(skb)->protocol, skb->csum)) {
 230                         IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 231                                          "Failed checksum for");
 232                         return 0;
 233                 }
 234                 break;
 235         default:
 236                 /* No need to checksum. */
 237                 break;
 238         }
 239
 240         return 1;
 241 }
 242
 243
 244 #define TCP_DIR_INPUT           0
 245 #define TCP_DIR_OUTPUT          4
 246 #define TCP_DIR_INPUT_ONLY      8
 247
 248 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 249         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 250         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 251         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 252 };
 253
 254 /*
 255  *      Timeout table[state]
 256  */
 257 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 258         [IP_VS_TCP_S_NONE]              =       2*HZ,
 259         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 260         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 261         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 262         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 263         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 264         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 265         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 266         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 267         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 268         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 269         [IP_VS_TCP_S_LAST]              =       2*HZ,
 270 };
 271
 272 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 273         [IP_VS_TCP_S_NONE]              =       "NONE",
 274         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 275         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 276         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 277         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 278         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 279         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 280         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 281         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 282         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 283         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 284         [IP_VS_TCP_S_LAST]              =       "BUG!",
 285 };
 286
 287 #define sNO IP_VS_TCP_S_NONE
 288 #define sES IP_VS_TCP_S_ESTABLISHED
 289 #define sSS IP_VS_TCP_S_SYN_SENT
 290 #define sSR IP_VS_TCP_S_SYN_RECV
 291 #define sFW IP_VS_TCP_S_FIN_WAIT
 292 #define sTW IP_VS_TCP_S_TIME_WAIT
 293 #define sCL IP_VS_TCP_S_CLOSE
 294 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 295 #define sLA IP_VS_TCP_S_LAST_ACK
 296 #define sLI IP_VS_TCP_S_LISTEN
 297 #define sSA IP_VS_TCP_S_SYNACK
 298
 299 struct tcp_states_t {
 300         int next_state[IP_VS_TCP_S_LAST];
 301 };
 302
 303 static const char * tcp_state_name(int state)
 304 {
 305         if (state >= IP_VS_TCP_S_LAST)
 306                 return "ERR!";
 307         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 308 }
 309
 310 static struct tcp_states_t tcp_states [] = {
 311 /*      INPUT */
 312 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 313 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 314 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 315 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 316 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 317
 318 /*      OUTPUT */
 319 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 320 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 321 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 322 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 323 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 324
 325 /*      INPUT-ONLY */
 326 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 327 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 328 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 329 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 330 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 331 };
 332
 333 static struct tcp_states_t tcp_states_dos [] = {
 334 /*      INPUT */
 335 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 336 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 337 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 338 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 339 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 340
 341 /*      OUTPUT */
 342 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 343 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 344 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 345 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 346 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 347
 348 /*      INPUT-ONLY */
 349 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 350 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 351 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 352 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 353 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 354 };
 355
 356 static struct tcp_states_t *tcp_state_table = tcp_states;
 357
 358
 359 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 360 {
 361         int on = (flags & 1);           /* secure_tcp */
 362
 363         /*
 364         ** FIXME: change secure_tcp to independent sysctl var
 365         ** or make it per-service or per-app because it is valid
 366         ** for most if not for all of the applications. Something
 367         ** like "capabilities" (flags) for each object.
 368         */
 369         tcp_state_table = (on? tcp_states_dos : tcp_states);
 370 }
 371
 372 static int
 373 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 374 {
 375         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 376                                        tcp_state_name_table, sname, to);
 377 }
 378
 379 static inline int tcp_state_idx(struct tcphdr *th)
 380 {
 381         if (th->rst)
 382                 return 3;
 383         if (th->syn)
 384                 return 0;
 385         if (th->fin)
 386                 return 1;
 387         if (th->ack)
 388                 return 2;
 389         return -1;
 390 }
 391
 392 static inline void
 393 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 394               int direction, struct tcphdr *th)
 395 {
 396         int state_idx;
 397         int new_state = IP_VS_TCP_S_CLOSE;
 398         int state_off = tcp_state_off[direction];
 399
 400         /*
 401          *    Update state offset to INPUT_ONLY if necessary
 402          *    or delete NO_OUTPUT flag if output packet detected
 403          */
 404         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 405                 if (state_off == TCP_DIR_OUTPUT)
 406                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 407                 else
 408                         state_off = TCP_DIR_INPUT_ONLY;
 409         }
 410
 411         if ((state_idx = tcp_state_idx(th)) < 0) {
 412                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 413                 goto tcp_state_out;
 414         }
 415
 416         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 417
 418   tcp_state_out:
 419         if (new_state != cp->state) {
 420                 struct ip_vs_dest *dest = cp->dest;
 421
 422                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 423                           "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
 424                           pp->name,
 425                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 426                           th->syn? 'S' : '.',
 427                           th->fin? 'F' : '.',
 428                           th->ack? 'A' : '.',
 429                           th->rst? 'R' : '.',
 430                           NIPQUAD(cp->daddr), ntohs(cp->dport),
 431                           NIPQUAD(cp->caddr), ntohs(cp->cport),
 432                           tcp_state_name(cp->state),
 433                           tcp_state_name(new_state),
 434                           atomic_read(&cp->refcnt));
 435                 if (dest) {
 436                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 437                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 438                                 atomic_dec(&dest->activeconns);
 439                                 atomic_inc(&dest->inactconns);
 440                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 441                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 442                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 443                                 atomic_inc(&dest->activeconns);
 444                                 atomic_dec(&dest->inactconns);
 445                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 446                         }
 447                 }
 448         }
 449
 450         cp->timeout = pp->timeout_table[cp->state = new_state];
 451 }
 452
 453
 454 /*
 455  *      Handle state transitions
 456  */
 457 static int
 458 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 459                      const struct sk_buff *skb,
 460                      struct ip_vs_protocol *pp)
 461 {
 462         struct tcphdr _tcph, *th;
 463
 464         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 465         if (th == NULL)
 466                 return 0;
 467
 468         spin_lock(&cp->lock);
 469         set_tcp_state(pp, cp, direction, th);
 470         spin_unlock(&cp->lock);
 471
 472         return 1;
 473 }
 474
 475
 476 /*
 477  *      Hash table for TCP application incarnations
 478  */
 479 #define TCP_APP_TAB_BITS        4
 480 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 481 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 482
 483 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 484 static DEFINE_SPINLOCK(tcp_app_lock);
 485
 486 static inline __u16 tcp_app_hashkey(__be16 port)
 487 {
 488         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 489                 & TCP_APP_TAB_MASK;
 490 }
 491
 492
 493 static int tcp_register_app(struct ip_vs_app *inc)
 494 {
 495         struct ip_vs_app *i;
 496         __u16 hash;
 497         __be16 port = inc->port;
 498         int ret = 0;
 499
 500         hash = tcp_app_hashkey(port);
 501
 502         spin_lock_bh(&tcp_app_lock);
 503         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 504                 if (i->port == port) {
 505                         ret = -EEXIST;
 506                         goto out;
 507                 }
 508         }
 509         list_add(&inc->p_list, &tcp_apps[hash]);
 510         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 511
 512   out:
 513         spin_unlock_bh(&tcp_app_lock);
 514         return ret;
 515 }
 516
 517
 518 static void
 519 tcp_unregister_app(struct ip_vs_app *inc)
 520 {
 521         spin_lock_bh(&tcp_app_lock);
 522         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 523         list_del(&inc->p_list);
 524         spin_unlock_bh(&tcp_app_lock);
 525 }
 526
 527
 528 static int
 529 tcp_app_conn_bind(struct ip_vs_conn *cp)
 530 {
 531         int hash;
 532         struct ip_vs_app *inc;
 533         int result = 0;
 534
 535         /* Default binding: bind app only for NAT */
 536         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 537                 return 0;
 538
 539         /* Lookup application incarnations and bind the right one */
 540         hash = tcp_app_hashkey(cp->vport);
 541
 542         spin_lock(&tcp_app_lock);
 543         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 544                 if (inc->port == cp->vport) {
 545                         if (unlikely(!ip_vs_app_inc_get(inc)))
 546                                 break;
 547                         spin_unlock(&tcp_app_lock);
 548
 549                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 550                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 551                                   __func__,
 552                                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 553                                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 554                                   inc->name, ntohs(inc->port));
 555                         cp->app = inc;
 556                         if (inc->init_conn)
 557                                 result = inc->init_conn(inc, cp);
 558                         goto out;
 559                 }
 560         }
 561         spin_unlock(&tcp_app_lock);
 562
 563   out:
 564         return result;
 565 }
 566
 567
 568 /*
 569  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 570  */
 571 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 572 {
 573         spin_lock(&cp->lock);
 574         cp->state = IP_VS_TCP_S_LISTEN;
 575         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 576         spin_unlock(&cp->lock);
 577 }
 578
 579
 580 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
 581 {
 582         IP_VS_INIT_HASH_TABLE(tcp_apps);
 583         pp->timeout_table = tcp_timeouts;
 584 }
 585
 586
 587 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
 588 {
 589 }
 590
 591
 592 struct ip_vs_protocol ip_vs_protocol_tcp = {
 593         .name =                 "TCP",
 594         .protocol =             IPPROTO_TCP,
 595         .num_states =           IP_VS_TCP_S_LAST,
 596         .dont_defrag =          0,
 597         .appcnt =               ATOMIC_INIT(0),
 598         .init =                 ip_vs_tcp_init,
 599         .exit =                 ip_vs_tcp_exit,
 600         .register_app =         tcp_register_app,
 601         .unregister_app =       tcp_unregister_app,
 602         .conn_schedule =        tcp_conn_schedule,
 603         .conn_in_get =          tcp_conn_in_get,
 604         .conn_out_get =         tcp_conn_out_get,
 605         .snat_handler =         tcp_snat_handler,
 606         .dnat_handler =         tcp_dnat_handler,
 607         .csum_check =           tcp_csum_check,
 608         .state_name =           tcp_state_name,
 609         .state_transition =     tcp_state_transition,
 610         .app_conn_bind =        tcp_app_conn_bind,
 611         .debug_packet =         ip_vs_tcpudp_debug_packet,
 612         .timeout_change =       tcp_timeout_change,
 613         .set_state_timeout =    tcp_set_state_timeout,
 614 };