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