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   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_ipv4.h>
  24
  25 #include <net/ip_vs.h>
  26
  27
  28 static struct ip_vs_conn *
  29 tcp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  30                 const struct iphdr *iph, unsigned int proto_off, int inverse)
  31 {
  32         __be16 _ports[2], *pptr;
  33
  34         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  35         if (pptr == NULL)
  36                 return NULL;
  37
  38         if (likely(!inverse)) {
  39                 return ip_vs_conn_in_get(iph->protocol,
  40                                          iph->saddr, pptr[0],
  41                                          iph->daddr, pptr[1]);
  42         } else {
  43                 return ip_vs_conn_in_get(iph->protocol,
  44                                          iph->daddr, pptr[1],
  45                                          iph->saddr, pptr[0]);
  46         }
  47 }
  48
  49 static struct ip_vs_conn *
  50 tcp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  51                  const struct iphdr *iph, unsigned int proto_off, int inverse)
  52 {
  53         __be16 _ports[2], *pptr;
  54
  55         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
  56         if (pptr == NULL)
  57                 return NULL;
  58
  59         if (likely(!inverse)) {
  60                 return ip_vs_conn_out_get(iph->protocol,
  61                                           iph->saddr, pptr[0],
  62                                           iph->daddr, pptr[1]);
  63         } else {
  64                 return ip_vs_conn_out_get(iph->protocol,
  65                                           iph->daddr, pptr[1],
  66                                           iph->saddr, pptr[0]);
  67         }
  68 }
  69
  70
  71 static int
  72 tcp_conn_schedule(struct sk_buff *skb,
  73                   struct ip_vs_protocol *pp,
  74                   int *verdict, struct ip_vs_conn **cpp)
  75 {
  76         struct ip_vs_service *svc;
  77         struct tcphdr _tcph, *th;
  78
  79         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
  80         if (th == NULL) {
  81                 *verdict = NF_DROP;
  82                 return 0;
  83         }
  84
  85         if (th->syn &&
  86             (svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
  87                                      ip_hdr(skb)->daddr, th->dest))) {
  88                 if (ip_vs_todrop()) {
  89                         /*
  90                          * It seems that we are very loaded.
  91                          * We have to drop this packet :(
  92                          */
  93                         ip_vs_service_put(svc);
  94                         *verdict = NF_DROP;
  95                         return 0;
  96                 }
  97
  98                 /*
  99                  * Let the virtual server select a real server for the
 100                  * incoming connection, and create a connection entry.
 101                  */
 102                 *cpp = ip_vs_schedule(svc, skb);
 103                 if (!*cpp) {
 104                         *verdict = ip_vs_leave(svc, skb, pp);
 105                         return 0;
 106                 }
 107                 ip_vs_service_put(svc);
 108         }
 109         return 1;
 110 }
 111
 112
 113 static inline void
 114 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
 115                      __be16 oldport, __be16 newport)
 116 {
 117         tcph->check =
 118                 csum_fold(ip_vs_check_diff4(oldip, newip,
 119                                  ip_vs_check_diff2(oldport, newport,
 120                                                 ~csum_unfold(tcph->check))));
 121 }
 122
 123
 124 static int
 125 tcp_snat_handler(struct sk_buff **pskb,
 126                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 127 {
 128         struct tcphdr *tcph;
 129         const unsigned int tcphoff = ip_hdrlen(*pskb);
 130
 131         /* csum_check requires unshared skb */
 132         if (!ip_vs_make_skb_writable(pskb, tcphoff+sizeof(*tcph)))
 133                 return 0;
 134
 135         if (unlikely(cp->app != NULL)) {
 136                 /* Some checks before mangling */
 137                 if (pp->csum_check && !pp->csum_check(*pskb, pp))
 138                         return 0;
 139
 140                 /* Call application helper if needed */
 141                 if (!ip_vs_app_pkt_out(cp, pskb))
 142                         return 0;
 143         }
 144
 145         tcph = (void *)ip_hdr(*pskb) + tcphoff;
 146         tcph->source = cp->vport;
 147
 148         /* Adjust TCP checksums */
 149         if (!cp->app) {
 150                 /* Only port and addr are changed, do fast csum update */
 151                 tcp_fast_csum_update(tcph, cp->daddr, cp->vaddr,
 152                                      cp->dport, cp->vport);
 153                 if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
 154                         (*pskb)->ip_summed = CHECKSUM_NONE;
 155         } else {
 156                 /* full checksum calculation */
 157                 tcph->check = 0;
 158                 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
 159                                              (*pskb)->len - tcphoff, 0);
 160                 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
 161                                                 (*pskb)->len - tcphoff,
 162                                                 cp->protocol,
 163                                                 (*pskb)->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 **pskb,
 174                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 175 {
 176         struct tcphdr *tcph;
 177         const unsigned int tcphoff = ip_hdrlen(*pskb);
 178
 179         /* csum_check requires unshared skb */
 180         if (!ip_vs_make_skb_writable(pskb, 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(*pskb, 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, pskb))
 193                         return 0;
 194         }
 195
 196         tcph = (void *)ip_hdr(*pskb) + 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, cp->daddr,
 205                                      cp->vport, cp->dport);
 206                 if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
 207                         (*pskb)->ip_summed = CHECKSUM_NONE;
 208         } else {
 209                 /* full checksum calculation */
 210                 tcph->check = 0;
 211                 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
 212                                              (*pskb)->len - tcphoff, 0);
 213                 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
 214                                                 (*pskb)->len - tcphoff,
 215                                                 cp->protocol,
 216                                                 (*pskb)->csum);
 217                 (*pskb)->ip_summed = CHECKSUM_UNNECESSARY;
 218         }
 219         return 1;
 220 }
 221
 222
 223 static int
 224 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
 225 {
 226         const unsigned int tcphoff = ip_hdrlen(skb);
 227
 228         switch (skb->ip_summed) {
 229         case CHECKSUM_NONE:
 230                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 231         case CHECKSUM_COMPLETE:
 232                 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 233                                       skb->len - tcphoff,
 234                                       ip_hdr(skb)->protocol, skb->csum)) {
 235                         IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 236                                          "Failed checksum for");
 237                         return 0;
 238                 }
 239                 break;
 240         default:
 241                 /* No need to checksum. */
 242                 break;
 243         }
 244
 245         return 1;
 246 }
 247
 248
 249 #define TCP_DIR_INPUT           0
 250 #define TCP_DIR_OUTPUT          4
 251 #define TCP_DIR_INPUT_ONLY      8
 252
 253 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 254         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 255         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 256         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 257 };
 258
 259 /*
 260  *      Timeout table[state]
 261  */
 262 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 263         [IP_VS_TCP_S_NONE]              =       2*HZ,
 264         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 265         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 266         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 267         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 268         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 269         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 270         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 271         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 272         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 273         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 274         [IP_VS_TCP_S_LAST]              =       2*HZ,
 275 };
 276
 277 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 278         [IP_VS_TCP_S_NONE]              =       "NONE",
 279         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 280         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 281         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 282         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 283         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 284         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 285         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 286         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 287         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 288         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 289         [IP_VS_TCP_S_LAST]              =       "BUG!",
 290 };
 291
 292 #define sNO IP_VS_TCP_S_NONE
 293 #define sES IP_VS_TCP_S_ESTABLISHED
 294 #define sSS IP_VS_TCP_S_SYN_SENT
 295 #define sSR IP_VS_TCP_S_SYN_RECV
 296 #define sFW IP_VS_TCP_S_FIN_WAIT
 297 #define sTW IP_VS_TCP_S_TIME_WAIT
 298 #define sCL IP_VS_TCP_S_CLOSE
 299 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 300 #define sLA IP_VS_TCP_S_LAST_ACK
 301 #define sLI IP_VS_TCP_S_LISTEN
 302 #define sSA IP_VS_TCP_S_SYNACK
 303
 304 struct tcp_states_t {
 305         int next_state[IP_VS_TCP_S_LAST];
 306 };
 307
 308 static const char * tcp_state_name(int state)
 309 {
 310         if (state >= IP_VS_TCP_S_LAST)
 311                 return "ERR!";
 312         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 313 }
 314
 315 static struct tcp_states_t tcp_states [] = {
 316 /*      INPUT */
 317 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 318 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 319 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 320 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 321 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 322
 323 /*      OUTPUT */
 324 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 325 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 326 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 327 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 328 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 329
 330 /*      INPUT-ONLY */
 331 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 332 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 333 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 334 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 335 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 336 };
 337
 338 static struct tcp_states_t tcp_states_dos [] = {
 339 /*      INPUT */
 340 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 341 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 342 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 343 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 344 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 345
 346 /*      OUTPUT */
 347 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 348 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 349 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 350 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 351 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 352
 353 /*      INPUT-ONLY */
 354 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 355 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 356 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 357 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 358 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 359 };
 360
 361 static struct tcp_states_t *tcp_state_table = tcp_states;
 362
 363
 364 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 365 {
 366         int on = (flags & 1);           /* secure_tcp */
 367
 368         /*
 369         ** FIXME: change secure_tcp to independent sysctl var
 370         ** or make it per-service or per-app because it is valid
 371         ** for most if not for all of the applications. Something
 372         ** like "capabilities" (flags) for each object.
 373         */
 374         tcp_state_table = (on? tcp_states_dos : tcp_states);
 375 }
 376
 377 static int
 378 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 379 {
 380         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 381                                        tcp_state_name_table, sname, to);
 382 }
 383
 384 static inline int tcp_state_idx(struct tcphdr *th)
 385 {
 386         if (th->rst)
 387                 return 3;
 388         if (th->syn)
 389                 return 0;
 390         if (th->fin)
 391                 return 1;
 392         if (th->ack)
 393                 return 2;
 394         return -1;
 395 }
 396
 397 static inline void
 398 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 399               int direction, struct tcphdr *th)
 400 {
 401         int state_idx;
 402         int new_state = IP_VS_TCP_S_CLOSE;
 403         int state_off = tcp_state_off[direction];
 404
 405         /*
 406          *    Update state offset to INPUT_ONLY if necessary
 407          *    or delete NO_OUTPUT flag if output packet detected
 408          */
 409         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 410                 if (state_off == TCP_DIR_OUTPUT)
 411                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 412                 else
 413                         state_off = TCP_DIR_INPUT_ONLY;
 414         }
 415
 416         if ((state_idx = tcp_state_idx(th)) < 0) {
 417                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 418                 goto tcp_state_out;
 419         }
 420
 421         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 422
 423   tcp_state_out:
 424         if (new_state != cp->state) {
 425                 struct ip_vs_dest *dest = cp->dest;
 426
 427                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 428                           "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
 429                           pp->name,
 430                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 431                           th->syn? 'S' : '.',
 432                           th->fin? 'F' : '.',
 433                           th->ack? 'A' : '.',
 434                           th->rst? 'R' : '.',
 435                           NIPQUAD(cp->daddr), ntohs(cp->dport),
 436                           NIPQUAD(cp->caddr), ntohs(cp->cport),
 437                           tcp_state_name(cp->state),
 438                           tcp_state_name(new_state),
 439                           atomic_read(&cp->refcnt));
 440                 if (dest) {
 441                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 442                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 443                                 atomic_dec(&dest->activeconns);
 444                                 atomic_inc(&dest->inactconns);
 445                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 446                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 447                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 448                                 atomic_inc(&dest->activeconns);
 449                                 atomic_dec(&dest->inactconns);
 450                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 451                         }
 452                 }
 453         }
 454
 455         cp->timeout = pp->timeout_table[cp->state = new_state];
 456 }
 457
 458
 459 /*
 460  *      Handle state transitions
 461  */
 462 static int
 463 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 464                      const struct sk_buff *skb,
 465                      struct ip_vs_protocol *pp)
 466 {
 467         struct tcphdr _tcph, *th;
 468
 469         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 470         if (th == NULL)
 471                 return 0;
 472
 473         spin_lock(&cp->lock);
 474         set_tcp_state(pp, cp, direction, th);
 475         spin_unlock(&cp->lock);
 476
 477         return 1;
 478 }
 479
 480
 481 /*
 482  *      Hash table for TCP application incarnations
 483  */
 484 #define TCP_APP_TAB_BITS        4
 485 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 486 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 487
 488 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 489 static DEFINE_SPINLOCK(tcp_app_lock);
 490
 491 static inline __u16 tcp_app_hashkey(__be16 port)
 492 {
 493         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 494                 & TCP_APP_TAB_MASK;
 495 }
 496
 497
 498 static int tcp_register_app(struct ip_vs_app *inc)
 499 {
 500         struct ip_vs_app *i;
 501         __u16 hash;
 502         __be16 port = inc->port;
 503         int ret = 0;
 504
 505         hash = tcp_app_hashkey(port);
 506
 507         spin_lock_bh(&tcp_app_lock);
 508         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 509                 if (i->port == port) {
 510                         ret = -EEXIST;
 511                         goto out;
 512                 }
 513         }
 514         list_add(&inc->p_list, &tcp_apps[hash]);
 515         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 516
 517   out:
 518         spin_unlock_bh(&tcp_app_lock);
 519         return ret;
 520 }
 521
 522
 523 static void
 524 tcp_unregister_app(struct ip_vs_app *inc)
 525 {
 526         spin_lock_bh(&tcp_app_lock);
 527         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 528         list_del(&inc->p_list);
 529         spin_unlock_bh(&tcp_app_lock);
 530 }
 531
 532
 533 static int
 534 tcp_app_conn_bind(struct ip_vs_conn *cp)
 535 {
 536         int hash;
 537         struct ip_vs_app *inc;
 538         int result = 0;
 539
 540         /* Default binding: bind app only for NAT */
 541         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 542                 return 0;
 543
 544         /* Lookup application incarnations and bind the right one */
 545         hash = tcp_app_hashkey(cp->vport);
 546
 547         spin_lock(&tcp_app_lock);
 548         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 549                 if (inc->port == cp->vport) {
 550                         if (unlikely(!ip_vs_app_inc_get(inc)))
 551                                 break;
 552                         spin_unlock(&tcp_app_lock);
 553
 554                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 555                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 556                                   __FUNCTION__,
 557                                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 558                                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 559                                   inc->name, ntohs(inc->port));
 560                         cp->app = inc;
 561                         if (inc->init_conn)
 562                                 result = inc->init_conn(inc, cp);
 563                         goto out;
 564                 }
 565         }
 566         spin_unlock(&tcp_app_lock);
 567
 568   out:
 569         return result;
 570 }
 571
 572
 573 /*
 574  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 575  */
 576 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 577 {
 578         spin_lock(&cp->lock);
 579         cp->state = IP_VS_TCP_S_LISTEN;
 580         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 581         spin_unlock(&cp->lock);
 582 }
 583
 584
 585 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
 586 {
 587         IP_VS_INIT_HASH_TABLE(tcp_apps);
 588         pp->timeout_table = tcp_timeouts;
 589 }
 590
 591
 592 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
 593 {
 594 }
 595
 596
 597 struct ip_vs_protocol ip_vs_protocol_tcp = {
 598         .name =                 "TCP",
 599         .protocol =             IPPROTO_TCP,
 600         .dont_defrag =          0,
 601         .appcnt =               ATOMIC_INIT(0),
 602         .init =                 ip_vs_tcp_init,
 603         .exit =                 ip_vs_tcp_exit,
 604         .register_app =         tcp_register_app,
 605         .unregister_app =       tcp_unregister_app,
 606         .conn_schedule =        tcp_conn_schedule,
 607         .conn_in_get =          tcp_conn_in_get,
 608         .conn_out_get =         tcp_conn_out_get,
 609         .snat_handler =         tcp_snat_handler,
 610         .dnat_handler =         tcp_dnat_handler,
 611         .csum_check =           tcp_csum_check,
 612         .state_name =           tcp_state_name,
 613         .state_transition =     tcp_state_transition,
 614         .app_conn_bind =        tcp_app_conn_bind,
 615         .debug_packet =         ip_vs_tcpudp_debug_packet,
 616         .timeout_change =       tcp_timeout_change,
 617         .set_state_timeout =    tcp_set_state_timeout,
 618 };