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   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(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
  29                 const struct ip_vs_iphdr *iph, unsigned int proto_off,
  30                 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.ip, pptr[0],
  41                                          iph->daddr.ip, pptr[1]);
  42         } else {
  43                 return ip_vs_conn_in_get(iph->protocol,
  44                                          iph->daddr.ip, pptr[1],
  45                                          iph->saddr.ip, pptr[0]);
  46         }
  47 }
  48
  49 static struct ip_vs_conn *
  50 tcp_conn_out_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
  51                  const struct ip_vs_iphdr *iph, unsigned int proto_off,
  52                  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.ip, pptr[0],
  63                                           iph->daddr.ip, pptr[1]);
  64         } else {
  65                 return ip_vs_conn_out_get(iph->protocol,
  66                                           iph->daddr.ip, pptr[1],
  67                                           iph->saddr.ip, pptr[0]);
  68         }
  69 }
  70
  71
  72 static int
  73 tcp_conn_schedule(int af, struct sk_buff *skb, 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         struct ip_vs_iphdr iph;
  79
  80         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
  81
  82         th = skb_header_pointer(skb, iph.len, sizeof(_tcph), &_tcph);
  83         if (th == NULL) {
  84                 *verdict = NF_DROP;
  85                 return 0;
  86         }
  87
  88         if (th->syn &&
  89             (svc = ip_vs_service_get(af, skb->mark, iph.protocol, &iph.daddr,
  90                                      th->dest))) {
  91                 if (ip_vs_todrop()) {
  92                         /*
  93                          * It seems that we are very loaded.
  94                          * We have to drop this packet :(
  95                          */
  96                         ip_vs_service_put(svc);
  97                         *verdict = NF_DROP;
  98                         return 0;
  99                 }
 100
 101                 /*
 102                  * Let the virtual server select a real server for the
 103                  * incoming connection, and create a connection entry.
 104                  */
 105                 *cpp = ip_vs_schedule(svc, skb);
 106                 if (!*cpp) {
 107                         *verdict = ip_vs_leave(svc, skb, pp);
 108                         return 0;
 109                 }
 110                 ip_vs_service_put(svc);
 111         }
 112         return 1;
 113 }
 114
 115
 116 static inline void
 117 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
 118                      __be16 oldport, __be16 newport)
 119 {
 120         tcph->check =
 121                 csum_fold(ip_vs_check_diff4(oldip, newip,
 122                                  ip_vs_check_diff2(oldport, newport,
 123                                                 ~csum_unfold(tcph->check))));
 124 }
 125
 126
 127 static int
 128 tcp_snat_handler(struct sk_buff *skb,
 129                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 130 {
 131         struct tcphdr *tcph;
 132         const unsigned int tcphoff = ip_hdrlen(skb);
 133
 134         /* csum_check requires unshared skb */
 135         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 136                 return 0;
 137
 138         if (unlikely(cp->app != NULL)) {
 139                 /* Some checks before mangling */
 140                 if (pp->csum_check && !pp->csum_check(AF_INET, skb, pp))
 141                         return 0;
 142
 143                 /* Call application helper if needed */
 144                 if (!ip_vs_app_pkt_out(cp, skb))
 145                         return 0;
 146         }
 147
 148         tcph = (void *)ip_hdr(skb) + tcphoff;
 149         tcph->source = cp->vport;
 150
 151         /* Adjust TCP checksums */
 152         if (!cp->app) {
 153                 /* Only port and addr are changed, do fast csum update */
 154                 tcp_fast_csum_update(tcph, cp->daddr.ip, cp->vaddr.ip,
 155                                      cp->dport, cp->vport);
 156                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 157                         skb->ip_summed = CHECKSUM_NONE;
 158         } else {
 159                 /* full checksum calculation */
 160                 tcph->check = 0;
 161                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 162                 tcph->check = csum_tcpudp_magic(cp->vaddr.ip, cp->caddr.ip,
 163                                                 skb->len - tcphoff,
 164                                                 cp->protocol, skb->csum);
 165                 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
 166                           pp->name, tcph->check,
 167                           (char*)&(tcph->check) - (char*)tcph);
 168         }
 169         return 1;
 170 }
 171
 172
 173 static int
 174 tcp_dnat_handler(struct sk_buff *skb,
 175                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 176 {
 177         struct tcphdr *tcph;
 178         const unsigned int tcphoff = ip_hdrlen(skb);
 179
 180         /* csum_check requires unshared skb */
 181         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 182                 return 0;
 183
 184         if (unlikely(cp->app != NULL)) {
 185                 /* Some checks before mangling */
 186                 if (pp->csum_check && !pp->csum_check(AF_INET, skb, pp))
 187                         return 0;
 188
 189                 /*
 190                  *      Attempt ip_vs_app call.
 191                  *      It will fix ip_vs_conn and iph ack_seq stuff
 192                  */
 193                 if (!ip_vs_app_pkt_in(cp, skb))
 194                         return 0;
 195         }
 196
 197         tcph = (void *)ip_hdr(skb) + tcphoff;
 198         tcph->dest = cp->dport;
 199
 200         /*
 201          *      Adjust TCP checksums
 202          */
 203         if (!cp->app) {
 204                 /* Only port and addr are changed, do fast csum update */
 205                 tcp_fast_csum_update(tcph, cp->vaddr.ip, cp->daddr.ip,
 206                                      cp->vport, cp->dport);
 207                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 208                         skb->ip_summed = CHECKSUM_NONE;
 209         } else {
 210                 /* full checksum calculation */
 211                 tcph->check = 0;
 212                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 213                 tcph->check = csum_tcpudp_magic(cp->caddr.ip, cp->daddr.ip,
 214                                                 skb->len - tcphoff,
 215                                                 cp->protocol, skb->csum);
 216                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 217         }
 218         return 1;
 219 }
 220
 221
 222 static int
 223 tcp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
 224 {
 225         unsigned int tcphoff;
 226
 227 #ifdef CONFIG_IP_VS_IPV6
 228         if (af == AF_INET6)
 229                 tcphoff = sizeof(struct ipv6hdr);
 230         else
 231 #endif
 232                 tcphoff = ip_hdrlen(skb);
 233
 234         switch (skb->ip_summed) {
 235         case CHECKSUM_NONE:
 236                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 237         case CHECKSUM_COMPLETE:
 238 #ifdef CONFIG_IP_VS_IPV6
 239                 if (af == AF_INET6) {
 240                         if (csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
 241                                             &ipv6_hdr(skb)->daddr,
 242                                             skb->len - tcphoff,
 243                                             ipv6_hdr(skb)->nexthdr,
 244                                             skb->csum)) {
 245                                 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 246                                                  "Failed checksum for");
 247                                 return 0;
 248                         }
 249                 } else
 250 #endif
 251                         if (csum_tcpudp_magic(ip_hdr(skb)->saddr,
 252                                               ip_hdr(skb)->daddr,
 253                                               skb->len - tcphoff,
 254                                               ip_hdr(skb)->protocol,
 255                                               skb->csum)) {
 256                                 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 257                                                  "Failed checksum for");
 258                                 return 0;
 259                         }
 260                 break;
 261         default:
 262                 /* No need to checksum. */
 263                 break;
 264         }
 265
 266         return 1;
 267 }
 268
 269
 270 #define TCP_DIR_INPUT           0
 271 #define TCP_DIR_OUTPUT          4
 272 #define TCP_DIR_INPUT_ONLY      8
 273
 274 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 275         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 276         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 277         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 278 };
 279
 280 /*
 281  *      Timeout table[state]
 282  */
 283 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 284         [IP_VS_TCP_S_NONE]              =       2*HZ,
 285         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 286         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 287         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 288         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 289         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 290         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 291         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 292         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 293         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 294         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 295         [IP_VS_TCP_S_LAST]              =       2*HZ,
 296 };
 297
 298 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 299         [IP_VS_TCP_S_NONE]              =       "NONE",
 300         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 301         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 302         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 303         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 304         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 305         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 306         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 307         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 308         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 309         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 310         [IP_VS_TCP_S_LAST]              =       "BUG!",
 311 };
 312
 313 #define sNO IP_VS_TCP_S_NONE
 314 #define sES IP_VS_TCP_S_ESTABLISHED
 315 #define sSS IP_VS_TCP_S_SYN_SENT
 316 #define sSR IP_VS_TCP_S_SYN_RECV
 317 #define sFW IP_VS_TCP_S_FIN_WAIT
 318 #define sTW IP_VS_TCP_S_TIME_WAIT
 319 #define sCL IP_VS_TCP_S_CLOSE
 320 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 321 #define sLA IP_VS_TCP_S_LAST_ACK
 322 #define sLI IP_VS_TCP_S_LISTEN
 323 #define sSA IP_VS_TCP_S_SYNACK
 324
 325 struct tcp_states_t {
 326         int next_state[IP_VS_TCP_S_LAST];
 327 };
 328
 329 static const char * tcp_state_name(int state)
 330 {
 331         if (state >= IP_VS_TCP_S_LAST)
 332                 return "ERR!";
 333         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 334 }
 335
 336 static struct tcp_states_t tcp_states [] = {
 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, sSR }},
 340 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 341 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 342 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 343
 344 /*      OUTPUT */
 345 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 346 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 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*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 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_states_dos [] = {
 360 /*      INPUT */
 361 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 362 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 363 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 364 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 365 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 366
 367 /*      OUTPUT */
 368 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 369 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 370 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 371 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 372 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 373
 374 /*      INPUT-ONLY */
 375 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 376 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 377 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 378 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 379 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 380 };
 381
 382 static struct tcp_states_t *tcp_state_table = tcp_states;
 383
 384
 385 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 386 {
 387         int on = (flags & 1);           /* secure_tcp */
 388
 389         /*
 390         ** FIXME: change secure_tcp to independent sysctl var
 391         ** or make it per-service or per-app because it is valid
 392         ** for most if not for all of the applications. Something
 393         ** like "capabilities" (flags) for each object.
 394         */
 395         tcp_state_table = (on? tcp_states_dos : tcp_states);
 396 }
 397
 398 static int
 399 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 400 {
 401         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 402                                        tcp_state_name_table, sname, to);
 403 }
 404
 405 static inline int tcp_state_idx(struct tcphdr *th)
 406 {
 407         if (th->rst)
 408                 return 3;
 409         if (th->syn)
 410                 return 0;
 411         if (th->fin)
 412                 return 1;
 413         if (th->ack)
 414                 return 2;
 415         return -1;
 416 }
 417
 418 static inline void
 419 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 420               int direction, struct tcphdr *th)
 421 {
 422         int state_idx;
 423         int new_state = IP_VS_TCP_S_CLOSE;
 424         int state_off = tcp_state_off[direction];
 425
 426         /*
 427          *    Update state offset to INPUT_ONLY if necessary
 428          *    or delete NO_OUTPUT flag if output packet detected
 429          */
 430         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 431                 if (state_off == TCP_DIR_OUTPUT)
 432                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 433                 else
 434                         state_off = TCP_DIR_INPUT_ONLY;
 435         }
 436
 437         if ((state_idx = tcp_state_idx(th)) < 0) {
 438                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 439                 goto tcp_state_out;
 440         }
 441
 442         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 443
 444   tcp_state_out:
 445         if (new_state != cp->state) {
 446                 struct ip_vs_dest *dest = cp->dest;
 447
 448                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 449                           "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
 450                           pp->name,
 451                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 452                           th->syn? 'S' : '.',
 453                           th->fin? 'F' : '.',
 454                           th->ack? 'A' : '.',
 455                           th->rst? 'R' : '.',
 456                           NIPQUAD(cp->daddr.ip), ntohs(cp->dport),
 457                           NIPQUAD(cp->caddr.ip), ntohs(cp->cport),
 458                           tcp_state_name(cp->state),
 459                           tcp_state_name(new_state),
 460                           atomic_read(&cp->refcnt));
 461                 if (dest) {
 462                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 463                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 464                                 atomic_dec(&dest->activeconns);
 465                                 atomic_inc(&dest->inactconns);
 466                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 467                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 468                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 469                                 atomic_inc(&dest->activeconns);
 470                                 atomic_dec(&dest->inactconns);
 471                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 472                         }
 473                 }
 474         }
 475
 476         cp->timeout = pp->timeout_table[cp->state = new_state];
 477 }
 478
 479
 480 /*
 481  *      Handle state transitions
 482  */
 483 static int
 484 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 485                      const struct sk_buff *skb,
 486                      struct ip_vs_protocol *pp)
 487 {
 488         struct tcphdr _tcph, *th;
 489
 490         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 491         if (th == NULL)
 492                 return 0;
 493
 494         spin_lock(&cp->lock);
 495         set_tcp_state(pp, cp, direction, th);
 496         spin_unlock(&cp->lock);
 497
 498         return 1;
 499 }
 500
 501
 502 /*
 503  *      Hash table for TCP application incarnations
 504  */
 505 #define TCP_APP_TAB_BITS        4
 506 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 507 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 508
 509 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 510 static DEFINE_SPINLOCK(tcp_app_lock);
 511
 512 static inline __u16 tcp_app_hashkey(__be16 port)
 513 {
 514         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 515                 & TCP_APP_TAB_MASK;
 516 }
 517
 518
 519 static int tcp_register_app(struct ip_vs_app *inc)
 520 {
 521         struct ip_vs_app *i;
 522         __u16 hash;
 523         __be16 port = inc->port;
 524         int ret = 0;
 525
 526         hash = tcp_app_hashkey(port);
 527
 528         spin_lock_bh(&tcp_app_lock);
 529         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 530                 if (i->port == port) {
 531                         ret = -EEXIST;
 532                         goto out;
 533                 }
 534         }
 535         list_add(&inc->p_list, &tcp_apps[hash]);
 536         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 537
 538   out:
 539         spin_unlock_bh(&tcp_app_lock);
 540         return ret;
 541 }
 542
 543
 544 static void
 545 tcp_unregister_app(struct ip_vs_app *inc)
 546 {
 547         spin_lock_bh(&tcp_app_lock);
 548         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 549         list_del(&inc->p_list);
 550         spin_unlock_bh(&tcp_app_lock);
 551 }
 552
 553
 554 static int
 555 tcp_app_conn_bind(struct ip_vs_conn *cp)
 556 {
 557         int hash;
 558         struct ip_vs_app *inc;
 559         int result = 0;
 560
 561         /* Default binding: bind app only for NAT */
 562         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 563                 return 0;
 564
 565         /* Lookup application incarnations and bind the right one */
 566         hash = tcp_app_hashkey(cp->vport);
 567
 568         spin_lock(&tcp_app_lock);
 569         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 570                 if (inc->port == cp->vport) {
 571                         if (unlikely(!ip_vs_app_inc_get(inc)))
 572                                 break;
 573                         spin_unlock(&tcp_app_lock);
 574
 575                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 576                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 577                                   __func__,
 578                                   NIPQUAD(cp->caddr.ip), ntohs(cp->cport),
 579                                   NIPQUAD(cp->vaddr.ip), ntohs(cp->vport),
 580                                   inc->name, ntohs(inc->port));
 581                         cp->app = inc;
 582                         if (inc->init_conn)
 583                                 result = inc->init_conn(inc, cp);
 584                         goto out;
 585                 }
 586         }
 587         spin_unlock(&tcp_app_lock);
 588
 589   out:
 590         return result;
 591 }
 592
 593
 594 /*
 595  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 596  */
 597 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 598 {
 599         spin_lock(&cp->lock);
 600         cp->state = IP_VS_TCP_S_LISTEN;
 601         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 602         spin_unlock(&cp->lock);
 603 }
 604
 605
 606 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
 607 {
 608         IP_VS_INIT_HASH_TABLE(tcp_apps);
 609         pp->timeout_table = tcp_timeouts;
 610 }
 611
 612
 613 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
 614 {
 615 }
 616
 617
 618 struct ip_vs_protocol ip_vs_protocol_tcp = {
 619         .name =                 "TCP",
 620         .protocol =             IPPROTO_TCP,
 621         .num_states =           IP_VS_TCP_S_LAST,
 622         .dont_defrag =          0,
 623         .appcnt =               ATOMIC_INIT(0),
 624         .init =                 ip_vs_tcp_init,
 625         .exit =                 ip_vs_tcp_exit,
 626         .register_app =         tcp_register_app,
 627         .unregister_app =       tcp_unregister_app,
 628         .conn_schedule =        tcp_conn_schedule,
 629         .conn_in_get =          tcp_conn_in_get,
 630         .conn_out_get =         tcp_conn_out_get,
 631         .snat_handler =         tcp_snat_handler,
 632         .dnat_handler =         tcp_dnat_handler,
 633         .csum_check =           tcp_csum_check,
 634         .state_name =           tcp_state_name,
 635         .state_transition =     tcp_state_transition,
 636         .app_conn_bind =        tcp_app_conn_bind,
 637         .debug_packet =         ip_vs_tcpudp_debug_packet,
 638         .timeout_change =       tcp_timeout_change,
 639         .set_state_timeout =    tcp_set_state_timeout,
 640 };