net/netfilter/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:     Hans Schillstrom <hans.schillstrom@ericsson.com>
  13  *
  14  *              Network name space (netns) aware.
  15  *              Global data moved to netns i.e struct netns_ipvs
  16  *              tcp_timeouts table has copy per netns in a hash table per
  17  *              protocol ip_vs_proto_data and is handled by netns
  18  */
  19
  20 #define KMSG_COMPONENT "IPVS"
  21 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/ip.h>
  25 #include <linux/tcp.h>                  /* for tcphdr */
  26 #include <net/ip.h>
  27 #include <net/tcp.h>                    /* for csum_tcpudp_magic */
  28 #include <net/ip6_checksum.h>
  29 #include <linux/netfilter.h>
  30 #include <linux/netfilter_ipv4.h>
  31
  32 #include <net/ip_vs.h>
  33
  34 static int
  35 tcp_conn_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
  36                   struct ip_vs_proto_data *pd,
  37                   int *verdict, struct ip_vs_conn **cpp,
  38                   struct ip_vs_iphdr *iph)
  39 {
  40         struct ip_vs_service *svc;
  41         struct tcphdr _tcph, *th;
  42         __be16 _ports[2], *ports = NULL;
  43
  44         /* In the event of icmp, we're only guaranteed to have the first 8
  45          * bytes of the transport header, so we only check the rest of the
  46          * TCP packet for non-ICMP packets
  47          */
  48         if (likely(!ip_vs_iph_icmp(iph))) {
  49                 th = skb_header_pointer(skb, iph->len, sizeof(_tcph), &_tcph);
  50                 if (th) {
  51                         if (th->rst || !(sysctl_sloppy_tcp(ipvs) || th->syn))
  52                                 return 1;
  53                         ports = &th->source;
  54                 }
  55         } else {
  56                 ports = skb_header_pointer(
  57                         skb, iph->len, sizeof(_ports), &_ports);
  58         }
  59
  60         if (!ports) {
  61                 *verdict = NF_DROP;
  62                 return 0;
  63         }
  64
  65         /* No !th->ack check to allow scheduling on SYN+ACK for Active FTP */
  66         rcu_read_lock();
  67
  68         if (likely(!ip_vs_iph_inverse(iph)))
  69                 svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
  70                                          &iph->daddr, ports[1]);
  71         else
  72                 svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
  73                                          &iph->saddr, ports[0]);
  74
  75         if (svc) {
  76                 int ignored;
  77
  78                 if (ip_vs_todrop(ipvs)) {
  79                         /*
  80                          * It seems that we are very loaded.
  81                          * We have to drop this packet :(
  82                          */
  83                         rcu_read_unlock();
  84                         *verdict = NF_DROP;
  85                         return 0;
  86                 }
  87
  88                 /*
  89                  * Let the virtual server select a real server for the
  90                  * incoming connection, and create a connection entry.
  91                  */
  92                 *cpp = ip_vs_schedule(svc, skb, pd, &ignored, iph);
  93                 if (!*cpp && ignored <= 0) {
  94                         if (!ignored)
  95                                 *verdict = ip_vs_leave(svc, skb, pd, iph);
  96                         else
  97                                 *verdict = NF_DROP;
  98                         rcu_read_unlock();
  99                         return 0;
 100                 }
 101         }
 102         rcu_read_unlock();
 103         /* NF_ACCEPT */
 104         return 1;
 105 }
 106
 107
 108 static inline void
 109 tcp_fast_csum_update(int af, struct tcphdr *tcph,
 110                      const union nf_inet_addr *oldip,
 111                      const union nf_inet_addr *newip,
 112                      __be16 oldport, __be16 newport)
 113 {
 114 #ifdef CONFIG_IP_VS_IPV6
 115         if (af == AF_INET6)
 116                 tcph->check =
 117                         csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
 118                                          ip_vs_check_diff2(oldport, newport,
 119                                                 ~csum_unfold(tcph->check))));
 120         else
 121 #endif
 122         tcph->check =
 123                 csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
 124                                  ip_vs_check_diff2(oldport, newport,
 125                                                 ~csum_unfold(tcph->check))));
 126 }
 127
 128
 129 static inline void
 130 tcp_partial_csum_update(int af, struct tcphdr *tcph,
 131                      const union nf_inet_addr *oldip,
 132                      const union nf_inet_addr *newip,
 133                      __be16 oldlen, __be16 newlen)
 134 {
 135 #ifdef CONFIG_IP_VS_IPV6
 136         if (af == AF_INET6)
 137                 tcph->check =
 138                         ~csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
 139                                          ip_vs_check_diff2(oldlen, newlen,
 140                                                 csum_unfold(tcph->check))));
 141         else
 142 #endif
 143         tcph->check =
 144                 ~csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
 145                                 ip_vs_check_diff2(oldlen, newlen,
 146                                                 csum_unfold(tcph->check))));
 147 }
 148
 149
 150 static int
 151 tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 152                  struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
 153 {
 154         struct tcphdr *tcph;
 155         unsigned int tcphoff = iph->len;
 156         int oldlen;
 157         int payload_csum = 0;
 158
 159 #ifdef CONFIG_IP_VS_IPV6
 160         if (cp->af == AF_INET6 && iph->fragoffs)
 161                 return 1;
 162 #endif
 163         oldlen = skb->len - tcphoff;
 164
 165         /* csum_check requires unshared skb */
 166         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 167                 return 0;
 168
 169         if (unlikely(cp->app != NULL)) {
 170                 int ret;
 171
 172                 /* Some checks before mangling */
 173                 if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
 174                         return 0;
 175
 176                 /* Call application helper if needed */
 177                 if (!(ret = ip_vs_app_pkt_out(cp, skb)))
 178                         return 0;
 179                 /* ret=2: csum update is needed after payload mangling */
 180                 if (ret == 1)
 181                         oldlen = skb->len - tcphoff;
 182                 else
 183                         payload_csum = 1;
 184         }
 185
 186         tcph = (void *)skb_network_header(skb) + tcphoff;
 187         tcph->source = cp->vport;
 188
 189         /* Adjust TCP checksums */
 190         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 191                 tcp_partial_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
 192                                         htons(oldlen),
 193                                         htons(skb->len - tcphoff));
 194         } else if (!payload_csum) {
 195                 /* Only port and addr are changed, do fast csum update */
 196                 tcp_fast_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
 197                                      cp->dport, cp->vport);
 198                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 199                         skb->ip_summed = (cp->app && pp->csum_check) ?
 200                                          CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
 201         } else {
 202                 /* full checksum calculation */
 203                 tcph->check = 0;
 204                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 205 #ifdef CONFIG_IP_VS_IPV6
 206                 if (cp->af == AF_INET6)
 207                         tcph->check = csum_ipv6_magic(&cp->vaddr.in6,
 208                                                       &cp->caddr.in6,
 209                                                       skb->len - tcphoff,
 210                                                       cp->protocol, skb->csum);
 211                 else
 212 #endif
 213                         tcph->check = csum_tcpudp_magic(cp->vaddr.ip,
 214                                                         cp->caddr.ip,
 215                                                         skb->len - tcphoff,
 216                                                         cp->protocol,
 217                                                         skb->csum);
 218                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 219
 220                 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
 221                           pp->name, tcph->check,
 222                           (char*)&(tcph->check) - (char*)tcph);
 223         }
 224         return 1;
 225 }
 226
 227
 228 static int
 229 tcp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 230                  struct ip_vs_conn *cp, struct ip_vs_iphdr *iph)
 231 {
 232         struct tcphdr *tcph;
 233         unsigned int tcphoff = iph->len;
 234         int oldlen;
 235         int payload_csum = 0;
 236
 237 #ifdef CONFIG_IP_VS_IPV6
 238         if (cp->af == AF_INET6 && iph->fragoffs)
 239                 return 1;
 240 #endif
 241         oldlen = skb->len - tcphoff;
 242
 243         /* csum_check requires unshared skb */
 244         if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
 245                 return 0;
 246
 247         if (unlikely(cp->app != NULL)) {
 248                 int ret;
 249
 250                 /* Some checks before mangling */
 251                 if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
 252                         return 0;
 253
 254                 /*
 255                  *      Attempt ip_vs_app call.
 256                  *      It will fix ip_vs_conn and iph ack_seq stuff
 257                  */
 258                 if (!(ret = ip_vs_app_pkt_in(cp, skb)))
 259                         return 0;
 260                 /* ret=2: csum update is needed after payload mangling */
 261                 if (ret == 1)
 262                         oldlen = skb->len - tcphoff;
 263                 else
 264                         payload_csum = 1;
 265         }
 266
 267         tcph = (void *)skb_network_header(skb) + tcphoff;
 268         tcph->dest = cp->dport;
 269
 270         /*
 271          *      Adjust TCP checksums
 272          */
 273         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 274                 tcp_partial_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
 275                                         htons(oldlen),
 276                                         htons(skb->len - tcphoff));
 277         } else if (!payload_csum) {
 278                 /* Only port and addr are changed, do fast csum update */
 279                 tcp_fast_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
 280                                      cp->vport, cp->dport);
 281                 if (skb->ip_summed == CHECKSUM_COMPLETE)
 282                         skb->ip_summed = (cp->app && pp->csum_check) ?
 283                                          CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
 284         } else {
 285                 /* full checksum calculation */
 286                 tcph->check = 0;
 287                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 288 #ifdef CONFIG_IP_VS_IPV6
 289                 if (cp->af == AF_INET6)
 290                         tcph->check = csum_ipv6_magic(&cp->caddr.in6,
 291                                                       &cp->daddr.in6,
 292                                                       skb->len - tcphoff,
 293                                                       cp->protocol, skb->csum);
 294                 else
 295 #endif
 296                         tcph->check = csum_tcpudp_magic(cp->caddr.ip,
 297                                                         cp->daddr.ip,
 298                                                         skb->len - tcphoff,
 299                                                         cp->protocol,
 300                                                         skb->csum);
 301                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 302         }
 303         return 1;
 304 }
 305
 306
 307 static int
 308 tcp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
 309 {
 310         unsigned int tcphoff;
 311
 312 #ifdef CONFIG_IP_VS_IPV6
 313         if (af == AF_INET6)
 314                 tcphoff = sizeof(struct ipv6hdr);
 315         else
 316 #endif
 317                 tcphoff = ip_hdrlen(skb);
 318
 319         switch (skb->ip_summed) {
 320         case CHECKSUM_NONE:
 321                 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
 322         case CHECKSUM_COMPLETE:
 323 #ifdef CONFIG_IP_VS_IPV6
 324                 if (af == AF_INET6) {
 325                         if (csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
 326                                             &ipv6_hdr(skb)->daddr,
 327                                             skb->len - tcphoff,
 328                                             ipv6_hdr(skb)->nexthdr,
 329                                             skb->csum)) {
 330                                 IP_VS_DBG_RL_PKT(0, af, pp, skb, 0,
 331                                                  "Failed checksum for");
 332                                 return 0;
 333                         }
 334                 } else
 335 #endif
 336                         if (csum_tcpudp_magic(ip_hdr(skb)->saddr,
 337                                               ip_hdr(skb)->daddr,
 338                                               skb->len - tcphoff,
 339                                               ip_hdr(skb)->protocol,
 340                                               skb->csum)) {
 341                                 IP_VS_DBG_RL_PKT(0, af, pp, skb, 0,
 342                                                  "Failed checksum for");
 343                                 return 0;
 344                         }
 345                 break;
 346         default:
 347                 /* No need to checksum. */
 348                 break;
 349         }
 350
 351         return 1;
 352 }
 353
 354
 355 #define TCP_DIR_INPUT           0
 356 #define TCP_DIR_OUTPUT          4
 357 #define TCP_DIR_INPUT_ONLY      8
 358
 359 static const int tcp_state_off[IP_VS_DIR_LAST] = {
 360         [IP_VS_DIR_INPUT]               =       TCP_DIR_INPUT,
 361         [IP_VS_DIR_OUTPUT]              =       TCP_DIR_OUTPUT,
 362         [IP_VS_DIR_INPUT_ONLY]          =       TCP_DIR_INPUT_ONLY,
 363 };
 364
 365 /*
 366  *      Timeout table[state]
 367  */
 368 static const int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
 369         [IP_VS_TCP_S_NONE]              =       2*HZ,
 370         [IP_VS_TCP_S_ESTABLISHED]       =       15*60*HZ,
 371         [IP_VS_TCP_S_SYN_SENT]          =       2*60*HZ,
 372         [IP_VS_TCP_S_SYN_RECV]          =       1*60*HZ,
 373         [IP_VS_TCP_S_FIN_WAIT]          =       2*60*HZ,
 374         [IP_VS_TCP_S_TIME_WAIT]         =       2*60*HZ,
 375         [IP_VS_TCP_S_CLOSE]             =       10*HZ,
 376         [IP_VS_TCP_S_CLOSE_WAIT]        =       60*HZ,
 377         [IP_VS_TCP_S_LAST_ACK]          =       30*HZ,
 378         [IP_VS_TCP_S_LISTEN]            =       2*60*HZ,
 379         [IP_VS_TCP_S_SYNACK]            =       120*HZ,
 380         [IP_VS_TCP_S_LAST]              =       2*HZ,
 381 };
 382
 383 static const char *const tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 384         [IP_VS_TCP_S_NONE]              =       "NONE",
 385         [IP_VS_TCP_S_ESTABLISHED]       =       "ESTABLISHED",
 386         [IP_VS_TCP_S_SYN_SENT]          =       "SYN_SENT",
 387         [IP_VS_TCP_S_SYN_RECV]          =       "SYN_RECV",
 388         [IP_VS_TCP_S_FIN_WAIT]          =       "FIN_WAIT",
 389         [IP_VS_TCP_S_TIME_WAIT]         =       "TIME_WAIT",
 390         [IP_VS_TCP_S_CLOSE]             =       "CLOSE",
 391         [IP_VS_TCP_S_CLOSE_WAIT]        =       "CLOSE_WAIT",
 392         [IP_VS_TCP_S_LAST_ACK]          =       "LAST_ACK",
 393         [IP_VS_TCP_S_LISTEN]            =       "LISTEN",
 394         [IP_VS_TCP_S_SYNACK]            =       "SYNACK",
 395         [IP_VS_TCP_S_LAST]              =       "BUG!",
 396 };
 397
 398 #define sNO IP_VS_TCP_S_NONE
 399 #define sES IP_VS_TCP_S_ESTABLISHED
 400 #define sSS IP_VS_TCP_S_SYN_SENT
 401 #define sSR IP_VS_TCP_S_SYN_RECV
 402 #define sFW IP_VS_TCP_S_FIN_WAIT
 403 #define sTW IP_VS_TCP_S_TIME_WAIT
 404 #define sCL IP_VS_TCP_S_CLOSE
 405 #define sCW IP_VS_TCP_S_CLOSE_WAIT
 406 #define sLA IP_VS_TCP_S_LAST_ACK
 407 #define sLI IP_VS_TCP_S_LISTEN
 408 #define sSA IP_VS_TCP_S_SYNACK
 409
 410 struct tcp_states_t {
 411         int next_state[IP_VS_TCP_S_LAST];
 412 };
 413
 414 static const char * tcp_state_name(int state)
 415 {
 416         if (state >= IP_VS_TCP_S_LAST)
 417                 return "ERR!";
 418         return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 419 }
 420
 421 static struct tcp_states_t tcp_states [] = {
 422 /*      INPUT */
 423 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 424 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 425 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
 426 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 427 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
 428
 429 /*      OUTPUT */
 430 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 431 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
 432 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 433 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 434 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 435
 436 /*      INPUT-ONLY */
 437 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 438 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
 439 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 440 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 441 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 442 };
 443
 444 static struct tcp_states_t tcp_states_dos [] = {
 445 /*      INPUT */
 446 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 447 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
 448 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
 449 /*ack*/ {{sES, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
 450 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 451
 452 /*      OUTPUT */
 453 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 454 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
 455 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
 456 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
 457 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
 458
 459 /*      INPUT-ONLY */
 460 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
 461 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
 462 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
 463 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
 464 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
 465 };
 466
 467 static void tcp_timeout_change(struct ip_vs_proto_data *pd, int flags)
 468 {
 469         int on = (flags & 1);           /* secure_tcp */
 470
 471         /*
 472         ** FIXME: change secure_tcp to independent sysctl var
 473         ** or make it per-service or per-app because it is valid
 474         ** for most if not for all of the applications. Something
 475         ** like "capabilities" (flags) for each object.
 476         */
 477         pd->tcp_state_table = (on ? tcp_states_dos : tcp_states);
 478 }
 479
 480 static inline int tcp_state_idx(struct tcphdr *th)
 481 {
 482         if (th->rst)
 483                 return 3;
 484         if (th->syn)
 485                 return 0;
 486         if (th->fin)
 487                 return 1;
 488         if (th->ack)
 489                 return 2;
 490         return -1;
 491 }
 492
 493 static inline void
 494 set_tcp_state(struct ip_vs_proto_data *pd, struct ip_vs_conn *cp,
 495               int direction, struct tcphdr *th)
 496 {
 497         int state_idx;
 498         int new_state = IP_VS_TCP_S_CLOSE;
 499         int state_off = tcp_state_off[direction];
 500
 501         /*
 502          *    Update state offset to INPUT_ONLY if necessary
 503          *    or delete NO_OUTPUT flag if output packet detected
 504          */
 505         if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
 506                 if (state_off == TCP_DIR_OUTPUT)
 507                         cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
 508                 else
 509                         state_off = TCP_DIR_INPUT_ONLY;
 510         }
 511
 512         if ((state_idx = tcp_state_idx(th)) < 0) {
 513                 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
 514                 goto tcp_state_out;
 515         }
 516
 517         new_state =
 518                 pd->tcp_state_table[state_off+state_idx].next_state[cp->state];
 519
 520   tcp_state_out:
 521         if (new_state != cp->state) {
 522                 struct ip_vs_dest *dest = cp->dest;
 523
 524                 IP_VS_DBG_BUF(8, "%s %s [%c%c%c%c] %s:%d->"
 525                               "%s:%d state: %s->%s conn->refcnt:%d\n",
 526                               pd->pp->name,
 527                               ((state_off == TCP_DIR_OUTPUT) ?
 528                                "output " : "input "),
 529                               th->syn ? 'S' : '.',
 530                               th->fin ? 'F' : '.',
 531                               th->ack ? 'A' : '.',
 532                               th->rst ? 'R' : '.',
 533                               IP_VS_DBG_ADDR(cp->daf, &cp->daddr),
 534                               ntohs(cp->dport),
 535                               IP_VS_DBG_ADDR(cp->af, &cp->caddr),
 536                               ntohs(cp->cport),
 537                               tcp_state_name(cp->state),
 538                               tcp_state_name(new_state),
 539                               atomic_read(&cp->refcnt));
 540
 541                 if (dest) {
 542                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 543                             (new_state != IP_VS_TCP_S_ESTABLISHED)) {
 544                                 atomic_dec(&dest->activeconns);
 545                                 atomic_inc(&dest->inactconns);
 546                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 547                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 548                                    (new_state == IP_VS_TCP_S_ESTABLISHED)) {
 549                                 atomic_inc(&dest->activeconns);
 550                                 atomic_dec(&dest->inactconns);
 551                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 552                         }
 553                 }
 554         }
 555
 556         if (likely(pd))
 557                 cp->timeout = pd->timeout_table[cp->state = new_state];
 558         else    /* What to do ? */
 559                 cp->timeout = tcp_timeouts[cp->state = new_state];
 560 }
 561
 562 /*
 563  *      Handle state transitions
 564  */
 565 static void
 566 tcp_state_transition(struct ip_vs_conn *cp, int direction,
 567                      const struct sk_buff *skb,
 568                      struct ip_vs_proto_data *pd)
 569 {
 570         struct tcphdr _tcph, *th;
 571
 572 #ifdef CONFIG_IP_VS_IPV6
 573         int ihl = cp->af == AF_INET ? ip_hdrlen(skb) : sizeof(struct ipv6hdr);
 574 #else
 575         int ihl = ip_hdrlen(skb);
 576 #endif
 577
 578         th = skb_header_pointer(skb, ihl, sizeof(_tcph), &_tcph);
 579         if (th == NULL)
 580                 return;
 581
 582         spin_lock_bh(&cp->lock);
 583         set_tcp_state(pd, cp, direction, th);
 584         spin_unlock_bh(&cp->lock);
 585 }
 586
 587 static inline __u16 tcp_app_hashkey(__be16 port)
 588 {
 589         return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
 590                 & TCP_APP_TAB_MASK;
 591 }
 592
 593
 594 static int tcp_register_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
 595 {
 596         struct ip_vs_app *i;
 597         __u16 hash;
 598         __be16 port = inc->port;
 599         int ret = 0;
 600         struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_TCP);
 601
 602         hash = tcp_app_hashkey(port);
 603
 604         list_for_each_entry(i, &ipvs->tcp_apps[hash], p_list) {
 605                 if (i->port == port) {
 606                         ret = -EEXIST;
 607                         goto out;
 608                 }
 609         }
 610         list_add_rcu(&inc->p_list, &ipvs->tcp_apps[hash]);
 611         atomic_inc(&pd->appcnt);
 612
 613   out:
 614         return ret;
 615 }
 616
 617
 618 static void
 619 tcp_unregister_app(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
 620 {
 621         struct ip_vs_proto_data *pd = ip_vs_proto_data_get(ipvs, IPPROTO_TCP);
 622
 623         atomic_dec(&pd->appcnt);
 624         list_del_rcu(&inc->p_list);
 625 }
 626
 627
 628 static int
 629 tcp_app_conn_bind(struct ip_vs_conn *cp)
 630 {
 631         struct netns_ipvs *ipvs = cp->ipvs;
 632         int hash;
 633         struct ip_vs_app *inc;
 634         int result = 0;
 635
 636         /* Default binding: bind app only for NAT */
 637         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
 638                 return 0;
 639
 640         /* Lookup application incarnations and bind the right one */
 641         hash = tcp_app_hashkey(cp->vport);
 642
 643         rcu_read_lock();
 644         list_for_each_entry_rcu(inc, &ipvs->tcp_apps[hash], p_list) {
 645                 if (inc->port == cp->vport) {
 646                         if (unlikely(!ip_vs_app_inc_get(inc)))
 647                                 break;
 648                         rcu_read_unlock();
 649
 650                         IP_VS_DBG_BUF(9, "%s(): Binding conn %s:%u->"
 651                                       "%s:%u to app %s on port %u\n",
 652                                       __func__,
 653                                       IP_VS_DBG_ADDR(cp->af, &cp->caddr),
 654                                       ntohs(cp->cport),
 655                                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
 656                                       ntohs(cp->vport),
 657                                       inc->name, ntohs(inc->port));
 658
 659                         cp->app = inc;
 660                         if (inc->init_conn)
 661                                 result = inc->init_conn(inc, cp);
 662                         goto out;
 663                 }
 664         }
 665         rcu_read_unlock();
 666
 667   out:
 668         return result;
 669 }
 670
 671
 672 /*
 673  *      Set LISTEN timeout. (ip_vs_conn_put will setup timer)
 674  */
 675 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
 676 {
 677         struct ip_vs_proto_data *pd = ip_vs_proto_data_get(cp->ipvs, IPPROTO_TCP);
 678
 679         spin_lock_bh(&cp->lock);
 680         cp->state = IP_VS_TCP_S_LISTEN;
 681         cp->timeout = (pd ? pd->timeout_table[IP_VS_TCP_S_LISTEN]
 682                            : tcp_timeouts[IP_VS_TCP_S_LISTEN]);
 683         spin_unlock_bh(&cp->lock);
 684 }
 685
 686 /* ---------------------------------------------
 687  *   timeouts is netns related now.
 688  * ---------------------------------------------
 689  */
 690 static int __ip_vs_tcp_init(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd)
 691 {
 692         ip_vs_init_hash_table(ipvs->tcp_apps, TCP_APP_TAB_SIZE);
 693         pd->timeout_table = ip_vs_create_timeout_table((int *)tcp_timeouts,
 694                                                         sizeof(tcp_timeouts));
 695         if (!pd->timeout_table)
 696                 return -ENOMEM;
 697         pd->tcp_state_table =  tcp_states;
 698         return 0;
 699 }
 700
 701 static void __ip_vs_tcp_exit(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd)
 702 {
 703         kfree(pd->timeout_table);
 704 }
 705
 706
 707 struct ip_vs_protocol ip_vs_protocol_tcp = {
 708         .name =                 "TCP",
 709         .protocol =             IPPROTO_TCP,
 710         .num_states =           IP_VS_TCP_S_LAST,
 711         .dont_defrag =          0,
 712         .init =                 NULL,
 713         .exit =                 NULL,
 714         .init_netns =           __ip_vs_tcp_init,
 715         .exit_netns =           __ip_vs_tcp_exit,
 716         .register_app =         tcp_register_app,
 717         .unregister_app =       tcp_unregister_app,
 718         .conn_schedule =        tcp_conn_schedule,
 719         .conn_in_get =          ip_vs_conn_in_get_proto,
 720         .conn_out_get =         ip_vs_conn_out_get_proto,
 721         .snat_handler =         tcp_snat_handler,
 722         .dnat_handler =         tcp_dnat_handler,
 723         .csum_check =           tcp_csum_check,
 724         .state_name =           tcp_state_name,
 725         .state_transition =     tcp_state_transition,
 726         .app_conn_bind =        tcp_app_conn_bind,
 727         .debug_packet =         ip_vs_tcpudp_debug_packet,
 728         .timeout_change =       tcp_timeout_change,
 729 };