err.no Git - linux-2.6/blob - net/ipv4/ipvs/ip_vs_proto_tcp.c

   1 /*
   2  * ip_vs_proto_tcp.c:   TCP load balancing support for IPVS
   3  *
   4  * Version:     $Id: ip_vs_proto_tcp.c,v 1.3 2002/11/30 01:50:35 wensong Exp $
   5  *
   6  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   7  *              Julian Anastasov <ja@ssi.bg>
   8  *
   9  *              This program is free software; you can redistribute it and/or
  10  *              modify it under the terms of the GNU General Public License
  11  *              as published by the Free Software Foundation; either version
  12  *              2 of the License, or (at your option) any later version.
  13  *
  14  * Changes:
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/ip.h>
  20 #include <linux/tcp.h>                  /* for tcphdr */
  21 #include <net/ip.h>
  22 #include <net/tcp.h>                    /* for csum_tcpudp_magic */
  23 #include <linux/netfilter.h>
  24 #include <linux/netfilter_ipv4.h>
  25
  26 #include <net/ip_vs.h>
  27
  28
  29 static struct ip_vs_conn *
  30 tcp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  31                 const struct iphdr *iph, unsigned int proto_off, int inverse)
  32 {
  33         __be16 _ports[2], *pptr;
  34
  35         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  36         if (pptr == NULL)
  37                 return NULL;
  38
  39         if (likely(!inverse)) {
  40                 return ip_vs_conn_in_get(iph->protocol,
  41                                          iph->saddr, pptr[0],
  42                                          iph->daddr, pptr[1]);
  43         } else {
  44                 return ip_vs_conn_in_get(iph->protocol,
  45                                          iph->daddr, pptr[1],
  46                                          iph->saddr, pptr[0]);
  47         }
  48 }
  49
  50 static struct ip_vs_conn *
  51 tcp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  52                  const struct iphdr *iph, unsigned int proto_off, int inverse)
  53 {
  54         __be16 _ports[2], *pptr;
  55
  56         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  57         if (pptr == NULL)
  58                 return NULL;
  59
  60         if (likely(!inverse)) {
  61                 return ip_vs_conn_out_get(iph->protocol,
  62                                           iph->saddr, pptr[0],
  63                                           iph->daddr, pptr[1]);
  64         } else {
  65                 return ip_vs_conn_out_get(iph->protocol,
  66                                           iph->daddr, pptr[1],
  67                                           iph->saddr, pptr[0]);
  68         }
  69 }
  70
  71
  72 static int
  73 tcp_conn_schedule(struct sk_buff *skb,
  74                   struct ip_vs_protocol *pp,
  75                   int *verdict, struct ip_vs_conn **cpp)
  76 {
  77         struct ip_vs_service *svc;
  78         struct tcphdr _tcph, *th;
  79
  80         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
  81         if (th == NULL) {
  82                 *verdict = NF_DROP;
  83                 return 0;
  84         }
  85
  86         if (th->syn &&
  87             (svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
  88                                      ip_hdr(skb)->daddr, th->dest))) {
  89                 if (ip_vs_todrop()) {
  90                         /*
  91                          * It seems that we are very loaded.
  92                          * We have to drop this packet :(
  93                          */
  94                         ip_vs_service_put(svc);
  95                         *verdict = NF_DROP;
  96                         return 0;
  97                 }
  98
  99                 /*
 100                  * Let the virtual server select a real server for the
 101                  * incoming connection, and create a connection entry.
 102                  */
 103                 *cpp = ip_vs_schedule(svc, skb);
 104                 if (!*cpp) {
 105                         *verdict = ip_vs_leave(svc, skb, pp);
 106                         return 0;
 107                 }
 108                 ip_vs_service_put(svc);
 109         }
 110         return 1;
 111 }
 112
 113
 114 static inline void
 115 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
 116                      __be16 oldport, __be16 newport)
 117 {
 118         tcph->check =
 119                 csum_fold(ip_vs_check_diff4(oldip, newip,
 120                                  ip_vs_check_diff2(oldport, newport,
 121                                                 ~csum_unfold(tcph->check))));
 122 }
 123
 124
 125 static int
 126 tcp_snat_handler(struct sk_buff *skb,
 127                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 128 {
 129         struct tcphdr *tcph;
 130         const unsigned int tcphoff = ip_hdrlen(skb);
 131
 132         /* csum_check requires unshared skb */
 133         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 134                 return 0;
 135
 136         if (unlikely(cp->app != NULL)) {
 137                 /* Some checks before mangling */
 138                 if (pp->csum_check && !pp->csum_check(skb, pp))
 139                         return 0;
 140
 141                 /* Call application helper if needed */
 142                 if (!ip_vs_app_pkt_out(cp, skb))
 143                         return 0;
 144         }
 145
 146         tcph = (void *)ip_hdr(skb) + tcphoff;
 147         tcph->source = cp->vport;
 148
 149         /* Adjust TCP checksums */
 150         if (!cp->app) {
 151                 /* Only port and addr are changed, do fast csum update */
 152                 tcp_fast_csum_update(tcph, cp->daddr, cp->vaddr,
 153                                      cp->dport, cp->vport);
 154                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 155                         skb->ip_summed = CHECKSUM_NONE;
 156         } else {
 157                 /* full checksum calculation */
 158                 tcph->check = 0;
 159                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 160                 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
 161                                                 skb->len - tcphoff,
 162                                                 cp->protocol, skb->csum);
 163                 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
 164                           pp->name, tcph->check,
 165                           (char*)&(tcph->check) - (char*)tcph);
 166         }
 167         return 1;
 168 }
 169
 170
 171 static int
 172 tcp_dnat_handler(struct sk_buff *skb,
 173                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 174 {
 175         struct tcphdr *tcph;
 176         const unsigned int tcphoff = ip_hdrlen(skb);
 177
 178         /* csum_check requires unshared skb */
 179         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 180                 return 0;
 181
 182         if (unlikely(cp->app != NULL)) {
 183                 /* Some checks before mangling */
 184                 if (pp->csum_check && !pp->csum_check(skb, pp))
 185                         return 0;
 186
 187                 /*
 188                  *      Attempt ip_vs_app call.
 189                  *      It will fix ip_vs_conn and iph ack_seq stuff
 190                  */
 191                 if (!ip_vs_app_pkt_in(cp, skb))
 192                         return 0;
 193         }
 194
 195         tcph = (void *)ip_hdr(skb) + tcphoff;
 196         tcph->dest = cp->dport;
 197
 198         /*
 199          *      Adjust TCP checksums
 200          */
 201         if (!cp->app) {
 202                 /* Only port and addr are changed, do fast csum update */
 203                 tcp_fast_csum_update(tcph, cp->vaddr, cp->daddr,
 204                                      cp->vport, cp->dport);
 205                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 206                         skb->ip_summed = CHECKSUM_NONE;
 207         } else {
 208                 /* full checksum calculation */
 209                 tcph->check = 0;
 210                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 211                 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
 212                                                 skb->len - tcphoff,
 213                                                 cp->protocol, skb->csum);
 214                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 215         }
 216         return 1;
 217 }
 218
 219
 220 static int
 221 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
 222 {
 223         const unsigned int tcphoff = ip_hdrlen(skb);
 224
 225         switch (skb->ip_summed) {
 226         case CHECKSUM_NONE:
 227                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 228         case CHECKSUM_COMPLETE:
 229                 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 230                                       skb->len - tcphoff,
 231                                       ip_hdr(skb)->protocol, skb->csum)) {
 232                         IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 233                                          "Failed checksum for");
 234                         return 0;
 235                 }
 236                 break;
 237         default:
 238                 /* No need to checksum. */
 239                 break;
 240         }
 241
 242         return 1;
 243 }
 244
 245
 246 #define TCP_DIR_INPUT           0
 247 #define TCP_DIR_OUTPUT          4
 248 #define TCP_DIR_INPUT_ONLY      8
 249
 250 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 251         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 252         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 253         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 254 };
 255
 256 /*
 257  *      Timeout table[state]
 258  */
 259 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 260         [IP_VS_TCP_S_NONE]              =       2*HZ,
 261         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 262         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 263         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 264         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 265         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 266         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 267         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 268         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 269         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 270         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 271         [IP_VS_TCP_S_LAST]              =       2*HZ,
 272 };
 273
 274 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 275         [IP_VS_TCP_S_NONE]              =       "NONE",
 276         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 277         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 278         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 279         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 280         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 281         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 282         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 283         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 284         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 285         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 286         [IP_VS_TCP_S_LAST]              =       "BUG!",
 287 };
 288
 289 #define sNO IP_VS_TCP_S_NONE
 290 #define sES IP_VS_TCP_S_ESTABLISHED
 291 #define sSS IP_VS_TCP_S_SYN_SENT
 292 #define sSR IP_VS_TCP_S_SYN_RECV
 293 #define sFW IP_VS_TCP_S_FIN_WAIT
 294 #define sTW IP_VS_TCP_S_TIME_WAIT
 295 #define sCL IP_VS_TCP_S_CLOSE
 296 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 297 #define sLA IP_VS_TCP_S_LAST_ACK
 298 #define sLI IP_VS_TCP_S_LISTEN
 299 #define sSA IP_VS_TCP_S_SYNACK
 300
 301 struct tcp_states_t {
 302         int next_state[IP_VS_TCP_S_LAST];
 303 };
 304
 305 static const char * tcp_state_name(int state)
 306 {
 307         if (state >= IP_VS_TCP_S_LAST)
 308                 return "ERR!";
 309         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 310 }
 311
 312 static struct tcp_states_t tcp_states [] = {
 313 /*      INPUT */
 314 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 315 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 316 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 317 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 318 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 319
 320 /*      OUTPUT */
 321 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 322 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 323 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 324 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 325 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 326
 327 /*      INPUT-ONLY */
 328 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 329 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 330 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 331 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 332 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 333 };
 334
 335 static struct tcp_states_t tcp_states_dos [] = {
 336 /*      INPUT */
 337 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 338 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 339 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 340 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 341 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 342
 343 /*      OUTPUT */
 344 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 345 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 346 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 347 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 348 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 349
 350 /*      INPUT-ONLY */
 351 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 352 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 353 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 354 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 355 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 356 };
 357
 358 static struct tcp_states_t *tcp_state_table = tcp_states;
 359
 360
 361 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 362 {
 363         int on = (flags & 1);           /* secure_tcp */
 364
 365         /*
 366         ** FIXME: change secure_tcp to independent sysctl var
 367         ** or make it per-service or per-app because it is valid
 368         ** for most if not for all of the applications. Something
 369         ** like "capabilities" (flags) for each object.
 370         */
 371         tcp_state_table = (on? tcp_states_dos : tcp_states);
 372 }
 373
 374 static int
 375 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 376 {
 377         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 378                                        tcp_state_name_table, sname, to);
 379 }
 380
 381 static inline int tcp_state_idx(struct tcphdr *th)
 382 {
 383         if (th->rst)
 384                 return 3;
 385         if (th->syn)
 386                 return 0;
 387         if (th->fin)
 388                 return 1;
 389         if (th->ack)
 390                 return 2;
 391         return -1;
 392 }
 393
 394 static inline void
 395 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 396               int direction, struct tcphdr *th)
 397 {
 398         int state_idx;
 399         int new_state = IP_VS_TCP_S_CLOSE;
 400         int state_off = tcp_state_off[direction];
 401
 402         /*
 403          *    Update state offset to INPUT_ONLY if necessary
 404          *    or delete NO_OUTPUT flag if output packet detected
 405          */
 406         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 407                 if (state_off == TCP_DIR_OUTPUT)
 408                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 409                 else
 410                         state_off = TCP_DIR_INPUT_ONLY;
 411         }
 412
 413         if ((state_idx = tcp_state_idx(th)) < 0) {
 414                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 415                 goto tcp_state_out;
 416         }
 417
 418         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 419
 420   tcp_state_out:
 421         if (new_state != cp->state) {
 422                 struct ip_vs_dest *dest = cp->dest;
 423
 424                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 425                           "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
 426                           pp->name,
 427                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 428                           th->syn? 'S' : '.',
 429                           th->fin? 'F' : '.',
 430                           th->ack? 'A' : '.',
 431                           th->rst? 'R' : '.',
 432                           NIPQUAD(cp->daddr), ntohs(cp->dport),
 433                           NIPQUAD(cp->caddr), ntohs(cp->cport),
 434                           tcp_state_name(cp->state),
 435                           tcp_state_name(new_state),
 436                           atomic_read(&cp->refcnt));
 437                 if (dest) {
 438                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 439                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 440                                 atomic_dec(&dest->activeconns);
 441                                 atomic_inc(&dest->inactconns);
 442                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 443                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 444                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 445                                 atomic_inc(&dest->activeconns);
 446                                 atomic_dec(&dest->inactconns);
 447                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 448                         }
 449                 }
 450         }
 451
 452         cp->timeout = pp->timeout_table[cp->state = new_state];
 453 }
 454
 455
 456 /*
 457  *      Handle state transitions
 458  */
 459 static int
 460 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 461                      const struct sk_buff *skb,
 462                      struct ip_vs_protocol *pp)
 463 {
 464         struct tcphdr _tcph, *th;
 465
 466         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 467         if (th == NULL)
 468                 return 0;
 469
 470         spin_lock(&cp->lock);
 471         set_tcp_state(pp, cp, direction, th);
 472         spin_unlock(&cp->lock);
 473
 474         return 1;
 475 }
 476
 477
 478 /*
 479  *      Hash table for TCP application incarnations
 480  */
 481 #define TCP_APP_TAB_BITS        4
 482 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 483 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 484
 485 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 486 static DEFINE_SPINLOCK(tcp_app_lock);
 487
 488 static inline __u16 tcp_app_hashkey(__be16 port)
 489 {
 490         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 491                 & TCP_APP_TAB_MASK;
 492 }
 493
 494
 495 static int tcp_register_app(struct ip_vs_app *inc)
 496 {
 497         struct ip_vs_app *i;
 498         __u16 hash;
 499         __be16 port = inc->port;
 500         int ret = 0;
 501
 502         hash = tcp_app_hashkey(port);
 503
 504         spin_lock_bh(&tcp_app_lock);
 505         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 506                 if (i->port == port) {
 507                         ret = -EEXIST;
 508                         goto out;
 509                 }
 510         }
 511         list_add(&inc->p_list, &tcp_apps[hash]);
 512         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 513
 514   out:
 515         spin_unlock_bh(&tcp_app_lock);
 516         return ret;
 517 }
 518
 519
 520 static void
 521 tcp_unregister_app(struct ip_vs_app *inc)
 522 {
 523         spin_lock_bh(&tcp_app_lock);
 524         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 525         list_del(&inc->p_list);
 526         spin_unlock_bh(&tcp_app_lock);
 527 }
 528
 529
 530 static int
 531 tcp_app_conn_bind(struct ip_vs_conn *cp)
 532 {
 533         int hash;
 534         struct ip_vs_app *inc;
 535         int result = 0;
 536
 537         /* Default binding: bind app only for NAT */
 538         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 539                 return 0;
 540
 541         /* Lookup application incarnations and bind the right one */
 542         hash = tcp_app_hashkey(cp->vport);
 543
 544         spin_lock(&tcp_app_lock);
 545         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 546                 if (inc->port == cp->vport) {
 547                         if (unlikely(!ip_vs_app_inc_get(inc)))
 548                                 break;
 549                         spin_unlock(&tcp_app_lock);
 550
 551                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 552                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 553                                   __func__,
 554                                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 555                                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 556                                   inc->name, ntohs(inc->port));
 557                         cp->app = inc;
 558                         if (inc->init_conn)
 559                                 result = inc->init_conn(inc, cp);
 560                         goto out;
 561                 }
 562         }
 563         spin_unlock(&tcp_app_lock);
 564
 565   out:
 566         return result;
 567 }
 568
 569
 570 /*
 571  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 572  */
 573 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 574 {
 575         spin_lock(&cp->lock);
 576         cp->state = IP_VS_TCP_S_LISTEN;
 577         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 578         spin_unlock(&cp->lock);
 579 }
 580
 581
 582 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
 583 {
 584         IP_VS_INIT_HASH_TABLE(tcp_apps);
 585         pp->timeout_table = tcp_timeouts;
 586 }
 587
 588
 589 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
 590 {
 591 }
 592
 593
 594 struct ip_vs_protocol ip_vs_protocol_tcp = {
 595         .name =                 "TCP",
 596         .protocol =             IPPROTO_TCP,
 597         .dont_defrag =          0,
 598         .appcnt =               ATOMIC_INIT(0),
 599         .init =                 ip_vs_tcp_init,
 600         .exit =                 ip_vs_tcp_exit,
 601         .register_app =         tcp_register_app,
 602         .unregister_app =       tcp_unregister_app,
 603         .conn_schedule =        tcp_conn_schedule,
 604         .conn_in_get =          tcp_conn_in_get,
 605         .conn_out_get =         tcp_conn_out_get,
 606         .snat_handler =         tcp_snat_handler,
 607         .dnat_handler =         tcp_dnat_handler,
 608         .csum_check =           tcp_csum_check,
 609         .state_name =           tcp_state_name,
 610         .state_transition =     tcp_state_transition,
 611         .app_conn_bind =        tcp_app_conn_bind,
 612         .debug_packet =         ip_vs_tcpudp_debug_packet,
 613         .timeout_change =       tcp_timeout_change,
 614         .set_state_timeout =    tcp_set_state_timeout,
 615 };