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_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         __u16 _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         __u16 _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, skb->nh.iph->ihl*4,
  80                                 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->nfmark, skb->nh.iph->protocol,
  88                                      skb->nh.iph->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, u32 oldip, u32 newip,
 116                      u16 oldport, u16 newport)
 117 {
 118         tcph->check =
 119                 ip_vs_check_diff(~oldip, newip,
 120                                  ip_vs_check_diff(oldport ^ 0xFFFF,
 121                                                   newport, tcph->check));
 122 }
 123
 124
 125 static int
 126 tcp_snat_handler(struct sk_buff **pskb,
 127                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 128 {
 129         struct tcphdr *tcph;
 130         unsigned int tcphoff = (*pskb)->nh.iph->ihl * 4;
 131
 132         /* csum_check requires unshared skb */
 133         if (!ip_vs_make_skb_writable(pskb, 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(*pskb, pp))
 139                         return 0;
 140
 141                 /* Call application helper if needed */
 142                 if (!ip_vs_app_pkt_out(cp, pskb))
 143                         return 0;
 144         }
 145
 146         tcph = (void *)(*pskb)->nh.iph + 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 ((*pskb)->ip_summed == CHECKSUM_HW)
 155                         (*pskb)->ip_summed = CHECKSUM_NONE;
 156         } else {
 157                 /* full checksum calculation */
 158                 tcph->check = 0;
 159                 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
 160                                              (*pskb)->len - tcphoff, 0);
 161                 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
 162                                                 (*pskb)->len - tcphoff,
 163                                                 cp->protocol,
 164                                                 (*pskb)->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 **pskb,
 175                  struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
 176 {
 177         struct tcphdr *tcph;
 178         unsigned int tcphoff = (*pskb)->nh.iph->ihl * 4;
 179
 180         /* csum_check requires unshared skb */
 181         if (!ip_vs_make_skb_writable(pskb, 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(*pskb, 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, pskb))
 194                         return 0;
 195         }
 196
 197         tcph = (void *)(*pskb)->nh.iph + 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, cp->daddr,
 206                                      cp->vport, cp->dport);
 207                 if ((*pskb)->ip_summed == CHECKSUM_HW)
 208                         (*pskb)->ip_summed = CHECKSUM_NONE;
 209         } else {
 210                 /* full checksum calculation */
 211                 tcph->check = 0;
 212                 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
 213                                              (*pskb)->len - tcphoff, 0);
 214                 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
 215                                                 (*pskb)->len - tcphoff,
 216                                                 cp->protocol,
 217                                                 (*pskb)->csum);
 218                 (*pskb)->ip_summed = CHECKSUM_UNNECESSARY;
 219         }
 220         return 1;
 221 }
 222
 223
 224 static int
 225 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
 226 {
 227         unsigned int tcphoff = skb->nh.iph->ihl*4;
 228
 229         switch (skb->ip_summed) {
 230         case CHECKSUM_NONE:
 231                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 232         case CHECKSUM_HW:
 233                 if (csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->daddr,
 234                                       skb->len - tcphoff,
 235                                       skb->nh.iph->protocol, skb->csum)) {
 236                         IP_VS_DBG_RL_PKT(0, pp, skb, 0,
 237                                          "Failed checksum for");
 238                         return 0;
 239                 }
 240                 break;
 241         default:
 242                 /* CHECKSUM_UNNECESSARY */
 243                 break;
 244         }
 245
 246         return 1;
 247 }
 248
 249
 250 #define TCP_DIR_INPUT           0
 251 #define TCP_DIR_OUTPUT          4
 252 #define TCP_DIR_INPUT_ONLY      8
 253
 254 static int tcp_state_off[IP_VS_DIR_LAST] = {
 255         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 256         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 257         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 258 };
 259
 260 /*
 261  *      Timeout table[state]
 262  */
 263 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 264         [IP_VS_TCP_S_NONE]              =       2*HZ,
 265         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 266         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 267         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 268         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 269         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 270         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 271         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 272         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 273         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 274         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 275         [IP_VS_TCP_S_LAST]              =       2*HZ,
 276 };
 277
 278
 279 #if 0
 280
 281 /* FIXME: This is going to die */
 282
 283 static int tcp_timeouts_dos[IP_VS_TCP_S_LAST+1] = {
 284         [IP_VS_TCP_S_NONE]              =       2*HZ,
 285         [IP_VS_TCP_S_ESTABLISHED]       =       8*60*HZ,
 286         [IP_VS_TCP_S_SYN_SENT]          =       60*HZ,
 287         [IP_VS_TCP_S_SYN_RECV]          =       10*HZ,
 288         [IP_VS_TCP_S_FIN_WAIT]          =       60*HZ,
 289         [IP_VS_TCP_S_TIME_WAIT]         =       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]            =       100*HZ,
 295         [IP_VS_TCP_S_LAST]              =       2*HZ,
 296 };
 297
 298 #endif
 299
 300 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 301         [IP_VS_TCP_S_NONE]              =       "NONE",
 302         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 303         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 304         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 305         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 306         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 307         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 308         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 309         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 310         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 311         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 312         [IP_VS_TCP_S_LAST]              =       "BUG!",
 313 };
 314
 315 #define sNO IP_VS_TCP_S_NONE
 316 #define sES IP_VS_TCP_S_ESTABLISHED
 317 #define sSS IP_VS_TCP_S_SYN_SENT
 318 #define sSR IP_VS_TCP_S_SYN_RECV
 319 #define sFW IP_VS_TCP_S_FIN_WAIT
 320 #define sTW IP_VS_TCP_S_TIME_WAIT
 321 #define sCL IP_VS_TCP_S_CLOSE
 322 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 323 #define sLA IP_VS_TCP_S_LAST_ACK
 324 #define sLI IP_VS_TCP_S_LISTEN
 325 #define sSA IP_VS_TCP_S_SYNACK
 326
 327 struct tcp_states_t {
 328         int next_state[IP_VS_TCP_S_LAST];
 329 };
 330
 331 static const char * tcp_state_name(int state)
 332 {
 333         if (state >= IP_VS_TCP_S_LAST)
 334                 return "ERR!";
 335         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 336 }
 337
 338 static struct tcp_states_t tcp_states [] = {
 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, sSR }},
 342 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 343 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 344 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 345
 346 /*      OUTPUT */
 347 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 348 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 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*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 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_states_dos [] = {
 362 /*      INPUT */
 363 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 364 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 365 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 366 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 367 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 368
 369 /*      OUTPUT */
 370 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 371 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 372 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 373 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 374 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 375
 376 /*      INPUT-ONLY */
 377 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 378 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 379 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 380 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 381 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 382 };
 383
 384 static struct tcp_states_t *tcp_state_table = tcp_states;
 385
 386
 387 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
 388 {
 389         int on = (flags & 1);           /* secure_tcp */
 390
 391         /*
 392         ** FIXME: change secure_tcp to independent sysctl var
 393         ** or make it per-service or per-app because it is valid
 394         ** for most if not for all of the applications. Something
 395         ** like "capabilities" (flags) for each object.
 396         */
 397         tcp_state_table = (on? tcp_states_dos : tcp_states);
 398 }
 399
 400 static int
 401 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 402 {
 403         return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
 404                                        tcp_state_name_table, sname, to);
 405 }
 406
 407 static inline int tcp_state_idx(struct tcphdr *th)
 408 {
 409         if (th->rst)
 410                 return 3;
 411         if (th->syn)
 412                 return 0;
 413         if (th->fin)
 414                 return 1;
 415         if (th->ack)
 416                 return 2;
 417         return -1;
 418 }
 419
 420 static inline void
 421 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
 422               int direction, struct tcphdr *th)
 423 {
 424         int state_idx;
 425         int new_state = IP_VS_TCP_S_CLOSE;
 426         int state_off = tcp_state_off[direction];
 427
 428         /*
 429          *    Update state offset to INPUT_ONLY if necessary
 430          *    or delete NO_OUTPUT flag if output packet detected
 431          */
 432         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 433                 if (state_off == TCP_DIR_OUTPUT)
 434                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 435                 else
 436                         state_off = TCP_DIR_INPUT_ONLY;
 437         }
 438
 439         if ((state_idx = tcp_state_idx(th)) < 0) {
 440                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 441                 goto tcp_state_out;
 442         }
 443
 444         new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
 445
 446   tcp_state_out:
 447         if (new_state != cp->state) {
 448                 struct ip_vs_dest *dest = cp->dest;
 449
 450                 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
 451                           "%u.%u.%u.%u:%d state: %s->%s cnt:%d\n",
 452                           pp->name,
 453                           (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
 454                           th->syn? 'S' : '.',
 455                           th->fin? 'F' : '.',
 456                           th->ack? 'A' : '.',
 457                           th->rst? 'R' : '.',
 458                           NIPQUAD(cp->daddr), ntohs(cp->dport),
 459                           NIPQUAD(cp->caddr), ntohs(cp->cport),
 460                           tcp_state_name(cp->state),
 461                           tcp_state_name(new_state),
 462                           atomic_read(&cp->refcnt));
 463                 if (dest) {
 464                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 465                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 466                                 atomic_dec(&dest->activeconns);
 467                                 atomic_inc(&dest->inactconns);
 468                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 469                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 470                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 471                                 atomic_inc(&dest->activeconns);
 472                                 atomic_dec(&dest->inactconns);
 473                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 474                         }
 475                 }
 476         }
 477
 478         cp->timeout = pp->timeout_table[cp->state = new_state];
 479 }
 480
 481
 482 /*
 483  *      Handle state transitions
 484  */
 485 static int
 486 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 487                      const struct sk_buff *skb,
 488                      struct ip_vs_protocol *pp)
 489 {
 490         struct tcphdr _tcph, *th;
 491
 492         th = skb_header_pointer(skb, skb->nh.iph->ihl*4,
 493                                 sizeof(_tcph), &_tcph);
 494         if (th == NULL)
 495                 return 0;
 496
 497         spin_lock(&cp->lock);
 498         set_tcp_state(pp, cp, direction, th);
 499         spin_unlock(&cp->lock);
 500
 501         return 1;
 502 }
 503
 504
 505 /*
 506  *      Hash table for TCP application incarnations
 507  */
 508 #define TCP_APP_TAB_BITS        4
 509 #define TCP_APP_TAB_SIZE        (1 << TCP_APP_TAB_BITS)
 510 #define TCP_APP_TAB_MASK        (TCP_APP_TAB_SIZE - 1)
 511
 512 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
 513 static DEFINE_SPINLOCK(tcp_app_lock);
 514
 515 static inline __u16 tcp_app_hashkey(__u16 port)
 516 {
 517         return ((port >> TCP_APP_TAB_BITS) ^ port) & TCP_APP_TAB_MASK;
 518 }
 519
 520
 521 static int tcp_register_app(struct ip_vs_app *inc)
 522 {
 523         struct ip_vs_app *i;
 524         __u16 hash, port = inc->port;
 525         int ret = 0;
 526
 527         hash = tcp_app_hashkey(port);
 528
 529         spin_lock_bh(&tcp_app_lock);
 530         list_for_each_entry(i, &tcp_apps[hash], p_list) {
 531                 if (i->port == port) {
 532                         ret = -EEXIST;
 533                         goto out;
 534                 }
 535         }
 536         list_add(&inc->p_list, &tcp_apps[hash]);
 537         atomic_inc(&ip_vs_protocol_tcp.appcnt);
 538
 539   out:
 540         spin_unlock_bh(&tcp_app_lock);
 541         return ret;
 542 }
 543
 544
 545 static void
 546 tcp_unregister_app(struct ip_vs_app *inc)
 547 {
 548         spin_lock_bh(&tcp_app_lock);
 549         atomic_dec(&ip_vs_protocol_tcp.appcnt);
 550         list_del(&inc->p_list);
 551         spin_unlock_bh(&tcp_app_lock);
 552 }
 553
 554
 555 static int
 556 tcp_app_conn_bind(struct ip_vs_conn *cp)
 557 {
 558         int hash;
 559         struct ip_vs_app *inc;
 560         int result = 0;
 561
 562         /* Default binding: bind app only for NAT */
 563         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 564                 return 0;
 565
 566         /* Lookup application incarnations and bind the right one */
 567         hash = tcp_app_hashkey(cp->vport);
 568
 569         spin_lock(&tcp_app_lock);
 570         list_for_each_entry(inc, &tcp_apps[hash], p_list) {
 571                 if (inc->port == cp->vport) {
 572                         if (unlikely(!ip_vs_app_inc_get(inc)))
 573                                 break;
 574                         spin_unlock(&tcp_app_lock);
 575
 576                         IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
 577                                   "%u.%u.%u.%u:%u to app %s on port %u\n",
 578                                   __FUNCTION__,
 579                                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 580                                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 581                                   inc->name, ntohs(inc->port));
 582                         cp->app = inc;
 583                         if (inc->init_conn)
 584                                 result = inc->init_conn(inc, cp);
 585                         goto out;
 586                 }
 587         }
 588         spin_unlock(&tcp_app_lock);
 589
 590   out:
 591         return result;
 592 }
 593
 594
 595 /*
 596  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 597  */
 598 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 599 {
 600         spin_lock(&cp->lock);
 601         cp->state = IP_VS_TCP_S_LISTEN;
 602         cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
 603         spin_unlock(&cp->lock);
 604 }
 605
 606
 607 static void tcp_init(struct ip_vs_protocol *pp)
 608 {
 609         IP_VS_INIT_HASH_TABLE(tcp_apps);
 610         pp->timeout_table = tcp_timeouts;
 611 }
 612
 613
 614 static void tcp_exit(struct ip_vs_protocol *pp)
 615 {
 616 }
 617
 618
 619 struct ip_vs_protocol ip_vs_protocol_tcp = {
 620         .name =                 "TCP",
 621         .protocol =             IPPROTO_TCP,
 622         .dont_defrag =          0,
 623         .appcnt =               ATOMIC_INIT(0),
 624         .init =                 tcp_init,
 625         .exit =                 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 };