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         struct ip_vs_iphdr iph;
  78
  79         ip_vs_fill_iphdr(AF_INET, skb_network_header(skb), &iph);
  80
  81         th = skb_header_pointer(skb, iph.len, sizeof(_tcph), &_tcph);
  82         if (th == NULL) {
  83                 *verdict = NF_DROP;
  84                 return 0;
  85         }
  86
  87         if (th->syn &&
  88             (svc = ip_vs_service_get(AF_INET, skb->mark, iph.protocol,
  89                                      &iph.daddr, th->dest))) {
  90                 if (ip_vs_todrop()) {
  91                         /*
  92                          * It seems that we are very loaded.
  93                          * We have to drop this packet :(
  94                          */
  95                         ip_vs_service_put(svc);
  96                         *verdict = NF_DROP;
  97                         return 0;
  98                 }
  99
 100                 /*
 101                  * Let the virtual server select a real server for the
 102                  * incoming connection, and create a connection entry.
 103                  */
 104                 *cpp = ip_vs_schedule(svc, skb);
 105                 if (!*cpp) {
 106                         *verdict = ip_vs_leave(svc, skb, pp);
 107                         return 0;
 108                 }
 109                 ip_vs_service_put(svc);
 110         }
 111         return 1;
 112 }
 113
 114
 115 static inline void
 116 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
 117                      __be16 oldport, __be16 newport)
 118 {
 119         tcph->check =
 120                 csum_fold(ip_vs_check_diff4(oldip, newip,
 121                                  ip_vs_check_diff2(oldport, newport,
 122                                                 ~csum_unfold(tcph->check))));
 123 }
 124
 125
 126 static int
 127 tcp_snat_handler(struct sk_buff *skb,
 128                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 129 {
 130         struct tcphdr *tcph;
 131         const unsigned int tcphoff = ip_hdrlen(skb);
 132
 133         /* csum_check requires unshared skb */
 134         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 135                 return 0;
 136
 137         if (unlikely(cp->app != NULL)) {
 138                 /* Some checks before mangling */
 139                 if (pp->csum_check && !pp->csum_check(skb, pp))
 140                         return 0;
 141
 142                 /* Call application helper if needed */
 143                 if (!ip_vs_app_pkt_out(cp, skb))
 144                         return 0;
 145         }
 146
 147         tcph = (void *)ip_hdr(skb) + tcphoff;
 148         tcph->source = cp->vport;
 149
 150         /* Adjust TCP checksums */
 151         if (!cp->app) {
 152                 /* Only port and addr are changed, do fast csum update */
 153                 tcp_fast_csum_update(tcph, cp->daddr.ip, cp->vaddr.ip,
 154                                      cp->dport, cp->vport);
 155                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 156                         skb->ip_summed = CHECKSUM_NONE;
 157         } else {
 158                 /* full checksum calculation */
 159                 tcph->check = 0;
 160                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 161                 tcph->check = csum_tcpudp_magic(cp->vaddr.ip, cp->caddr.ip,
 162                                                 skb->len - tcphoff,
 163                                                 cp->protocol, skb->csum);
 164                 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
 165                           pp->name, tcph->check,
 166                           (char*)&(tcph->check) - (char*)tcph);
 167         }
 168         return 1;
 169 }
 170
 171
 172 static int
 173 tcp_dnat_handler(struct sk_buff *skb,
 174                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 175 {
 176         struct tcphdr *tcph;
 177         const unsigned int tcphoff = ip_hdrlen(skb);
 178
 179         /* csum_check requires unshared skb */
 180         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 181                 return 0;
 182
 183         if (unlikely(cp->app != NULL)) {
 184                 /* Some checks before mangling */
 185                 if (pp->csum_check && !pp->csum_check(skb, pp))
 186                         return 0;
 187
 188                 /*
 189                  *      Attempt ip_vs_app call.
 190                  *      It will fix ip_vs_conn and iph ack_seq stuff
 191                  */
 192                 if (!ip_vs_app_pkt_in(cp, skb))
 193                         return 0;
 194         }
 195
 196         tcph = (void *)ip_hdr(skb) + tcphoff;
 197         tcph->dest = cp->dport;
 198
 199         /*
 200          *      Adjust TCP checksums
 201          */
 202         if (!cp->app) {
 203                 /* Only port and addr are changed, do fast csum update */
 204                 tcp_fast_csum_update(tcph, cp->vaddr.ip, cp->daddr.ip,
 205                                      cp->vport, cp->dport);
 206                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 207                         skb->ip_summed = CHECKSUM_NONE;
 208         } else {
 209                 /* full checksum calculation */
 210                 tcph->check = 0;
 211                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 212                 tcph->check = csum_tcpudp_magic(cp->caddr.ip, cp->daddr.ip,
 213                                                 skb->len - tcphoff,
 214                                                 cp->protocol, skb->csum);
 215                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 216         }
 217         return 1;
 218 }
 219
 220
 221 static int
 222 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
 223 {
 224         const unsigned int tcphoff = ip_hdrlen(skb);
 225
 226         switch (skb->ip_summed) {
 227         case CHECKSUM_NONE:
 228                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 229         case CHECKSUM_COMPLETE:
 230                 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 231                                       skb->len - tcphoff,
 232                                       ip_hdr(skb)->protocol, skb->csum)) {
 233                         IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 234                                          "Failed checksum for");
 235                         return 0;
 236                 }
 237                 break;
 238         default:
 239                 /* No need to checksum. */
 240                 break;
 241         }
 242
 243         return 1;
 244 }
 245
 246
 247 #define TCP_DIR_INPUT           0
 248 #define TCP_DIR_OUTPUT          4
 249 #define TCP_DIR_INPUT_ONLY      8
 250
 251 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 252         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 253         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 254         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 255 };
 256
 257 /*
 258  *      Timeout table[state]
 259  */
 260 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 261         [IP_VS_TCP_S_NONE]              =       2*HZ,
 262         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 263         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 264         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 265         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 266         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 267         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 268         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 269         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 270         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 271         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 272         [IP_VS_TCP_S_LAST]              =       2*HZ,
 273 };
 274
 275 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 276         [IP_VS_TCP_S_NONE]              =       "NONE",
 277         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 278         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 279         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 280         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 281         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 282         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 283         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 284         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 285         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 286         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 287         [IP_VS_TCP_S_LAST]              =       "BUG!",
 288 };
 289
 290 #define sNO IP_VS_TCP_S_NONE
 291 #define sES IP_VS_TCP_S_ESTABLISHED
 292 #define sSS IP_VS_TCP_S_SYN_SENT
 293 #define sSR IP_VS_TCP_S_SYN_RECV
 294 #define sFW IP_VS_TCP_S_FIN_WAIT
 295 #define sTW IP_VS_TCP_S_TIME_WAIT
 296 #define sCL IP_VS_TCP_S_CLOSE
 297 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 298 #define sLA IP_VS_TCP_S_LAST_ACK
 299 #define sLI IP_VS_TCP_S_LISTEN
 300 #define sSA IP_VS_TCP_S_SYNACK
 301
 302 struct tcp_states_t {
 303         int next_state[IP_VS_TCP_S_LAST];
 304 };
 305
 306 static const char * tcp_state_name(int state)
 307 {
 308         if (state >= IP_VS_TCP_S_LAST)
 309                 return "ERR!";
 310         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 311 }
 312
 313 static struct tcp_states_t tcp_states [] = {
 314 /*      INPUT */
 315 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 316 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 317 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 318 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 319 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 320
 321 /*      OUTPUT */
 322 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 323 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 324 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 325 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 326 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 327
 328 /*      INPUT-ONLY */
 329 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 330 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 331 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 332 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 333 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 334 };
 335
 336 static struct tcp_states_t tcp_states_dos [] = {
 337 /*      INPUT */
 338 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 339 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 340 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 341 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 342 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 343
 344 /*      OUTPUT */
 345 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 346 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 347 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 348 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 349 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 350
 351 /*      INPUT-ONLY */
 352 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 353 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 354 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 355 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 356 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 357 };
 358
 359 static struct tcp_states_t *tcp_state_table = tcp_states;
 360
 361
 362 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 363 {
 364         int on = (flags & 1);           /* secure_tcp */
 365
 366         /*
 367         ** FIXME: change secure_tcp to independent sysctl var
 368         ** or make it per-service or per-app because it is valid
 369         ** for most if not for all of the applications. Something
 370         ** like "capabilities" (flags) for each object.
 371         */
 372         tcp_state_table = (on? tcp_states_dos : tcp_states);
 373 }
 374
 375 static int
 376 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 377 {
 378         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 379                                        tcp_state_name_table, sname, to);
 380 }
 381
 382 static inline int tcp_state_idx(struct tcphdr *th)
 383 {
 384         if (th->rst)
 385                 return 3;
 386         if (th->syn)
 387                 return 0;
 388         if (th->fin)
 389                 return 1;
 390         if (th->ack)
 391                 return 2;
 392         return -1;
 393 }
 394
 395 static inline void
 396 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 397               int direction, struct tcphdr *th)
 398 {
 399         int state_idx;
 400         int new_state = IP_VS_TCP_S_CLOSE;
 401         int state_off = tcp_state_off[direction];
 402
 403         /*
 404          *    Update state offset to INPUT_ONLY if necessary
 405          *    or delete NO_OUTPUT flag if output packet detected
 406          */
 407         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 408                 if (state_off == TCP_DIR_OUTPUT)
 409                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 410                 else
 411                         state_off = TCP_DIR_INPUT_ONLY;
 412         }
 413
 414         if ((state_idx = tcp_state_idx(th)) < 0) {
 415                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 416                 goto tcp_state_out;
 417         }
 418
 419         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 420
 421   tcp_state_out:
 422         if (new_state != cp->state) {
 423                 struct ip_vs_dest *dest = cp->dest;
 424
 425                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 426                           "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
 427                           pp->name,
 428                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 429                           th->syn? 'S' : '.',
 430                           th->fin? 'F' : '.',
 431                           th->ack? 'A' : '.',
 432                           th->rst? 'R' : '.',
 433                           NIPQUAD(cp->daddr.ip), ntohs(cp->dport),
 434                           NIPQUAD(cp->caddr.ip), ntohs(cp->cport),
 435                           tcp_state_name(cp->state),
 436                           tcp_state_name(new_state),
 437                           atomic_read(&cp->refcnt));
 438                 if (dest) {
 439                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 440                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 441                                 atomic_dec(&dest->activeconns);
 442                                 atomic_inc(&dest->inactconns);
 443                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 444                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 445                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 446                                 atomic_inc(&dest->activeconns);
 447                                 atomic_dec(&dest->inactconns);
 448                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 449                         }
 450                 }
 451         }
 452
 453         cp->timeout = pp->timeout_table[cp->state = new_state];
 454 }
 455
 456
 457 /*
 458  *      Handle state transitions
 459  */
 460 static int
 461 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 462                      const struct sk_buff *skb,
 463                      struct ip_vs_protocol *pp)
 464 {
 465         struct tcphdr _tcph, *th;
 466
 467         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 468         if (th == NULL)
 469                 return 0;
 470
 471         spin_lock(&cp->lock);
 472         set_tcp_state(pp, cp, direction, th);
 473         spin_unlock(&cp->lock);
 474
 475         return 1;
 476 }
 477
 478
 479 /*
 480  *      Hash table for TCP application incarnations
 481  */
 482 #define TCP_APP_TAB_BITS        4
 483 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 484 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 485
 486 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 487 static DEFINE_SPINLOCK(tcp_app_lock);
 488
 489 static inline __u16 tcp_app_hashkey(__be16 port)
 490 {
 491         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 492                 & TCP_APP_TAB_MASK;
 493 }
 494
 495
 496 static int tcp_register_app(struct ip_vs_app *inc)
 497 {
 498         struct ip_vs_app *i;
 499         __u16 hash;
 500         __be16 port = inc->port;
 501         int ret = 0;
 502
 503         hash = tcp_app_hashkey(port);
 504
 505         spin_lock_bh(&tcp_app_lock);
 506         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 507                 if (i->port == port) {
 508                         ret = -EEXIST;
 509                         goto out;
 510                 }
 511         }
 512         list_add(&inc->p_list, &tcp_apps[hash]);
 513         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 514
 515   out:
 516         spin_unlock_bh(&tcp_app_lock);
 517         return ret;
 518 }
 519
 520
 521 static void
 522 tcp_unregister_app(struct ip_vs_app *inc)
 523 {
 524         spin_lock_bh(&tcp_app_lock);
 525         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 526         list_del(&inc->p_list);
 527         spin_unlock_bh(&tcp_app_lock);
 528 }
 529
 530
 531 static int
 532 tcp_app_conn_bind(struct ip_vs_conn *cp)
 533 {
 534         int hash;
 535         struct ip_vs_app *inc;
 536         int result = 0;
 537
 538         /* Default binding: bind app only for NAT */
 539         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 540                 return 0;
 541
 542         /* Lookup application incarnations and bind the right one */
 543         hash = tcp_app_hashkey(cp->vport);
 544
 545         spin_lock(&tcp_app_lock);
 546         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 547                 if (inc->port == cp->vport) {
 548                         if (unlikely(!ip_vs_app_inc_get(inc)))
 549                                 break;
 550                         spin_unlock(&tcp_app_lock);
 551
 552                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 553                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 554                                   __func__,
 555                                   NIPQUAD(cp->caddr.ip), ntohs(cp->cport),
 556                                   NIPQUAD(cp->vaddr.ip), ntohs(cp->vport),
 557                                   inc->name, ntohs(inc->port));
 558                         cp->app = inc;
 559                         if (inc->init_conn)
 560                                 result = inc->init_conn(inc, cp);
 561                         goto out;
 562                 }
 563         }
 564         spin_unlock(&tcp_app_lock);
 565
 566   out:
 567         return result;
 568 }
 569
 570
 571 /*
 572  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 573  */
 574 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 575 {
 576         spin_lock(&cp->lock);
 577         cp->state = IP_VS_TCP_S_LISTEN;
 578         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 579         spin_unlock(&cp->lock);
 580 }
 581
 582
 583 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
 584 {
 585         IP_VS_INIT_HASH_TABLE(tcp_apps);
 586         pp->timeout_table = tcp_timeouts;
 587 }
 588
 589
 590 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
 591 {
 592 }
 593
 594
 595 struct ip_vs_protocol ip_vs_protocol_tcp = {
 596         .name =                 "TCP",
 597         .protocol =             IPPROTO_TCP,
 598         .num_states =           IP_VS_TCP_S_LAST,
 599         .dont_defrag =          0,
 600         .appcnt =               ATOMIC_INIT(0),
 601         .init =                 ip_vs_tcp_init,
 602         .exit =                 ip_vs_tcp_exit,
 603         .register_app =         tcp_register_app,
 604         .unregister_app =       tcp_unregister_app,
 605         .conn_schedule =        tcp_conn_schedule,
 606         .conn_in_get =          tcp_conn_in_get,
 607         .conn_out_get =         tcp_conn_out_get,
 608         .snat_handler =         tcp_snat_handler,
 609         .dnat_handler =         tcp_dnat_handler,
 610         .csum_check =           tcp_csum_check,
 611         .state_name =           tcp_state_name,
 612         .state_transition =     tcp_state_transition,
 613         .app_conn_bind =        tcp_app_conn_bind,
 614         .debug_packet =         ip_vs_tcpudp_debug_packet,
 615         .timeout_change =       tcp_timeout_change,
 616         .set_state_timeout =    tcp_set_state_timeout,
 617 };