net/netfilter/ipvs/ip_vs_sync.c

   1 /*
   2  * IPVS         An implementation of the IP virtual server support for the
   3  *              LINUX operating system.  IPVS is now implemented as a module
   4  *              over the NetFilter framework. IPVS can be used to build a
   5  *              high-performance and highly available server based on a
   6  *              cluster of servers.
   7  *
   8  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   9  *
  10  * ip_vs_sync:  sync connection info from master load balancer to backups
  11  *              through multicast
  12  *
  13  * Changes:
  14  *      Alexandre Cassen        :       Added master & backup support at a time.
  15  *      Alexandre Cassen        :       Added SyncID support for incoming sync
  16  *                                      messages filtering.
  17  *      Justin Ossevoort        :       Fix endian problem on sync message size.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/inetdevice.h>
  23 #include <linux/net.h>
  24 #include <linux/completion.h>
  25 #include <linux/delay.h>
  26 #include <linux/skbuff.h>
  27 #include <linux/in.h>
  28 #include <linux/igmp.h>                 /* for ip_mc_join_group */
  29 #include <linux/udp.h>
  30 #include <linux/err.h>
  31 #include <linux/kthread.h>
  32 #include <linux/wait.h>
  33 #include <linux/kernel.h>
  34
  35 #include <net/ip.h>
  36 #include <net/sock.h>
  37
  38 #include <net/ip_vs.h>
  39
  40 #define IP_VS_SYNC_GROUP 0xe0000051    /* multicast addr - 224.0.0.81 */
  41 #define IP_VS_SYNC_PORT  8848          /* multicast port */
  42
  43
  44 /*
  45  *      IPVS sync connection entry
  46  */
  47 struct ip_vs_sync_conn {
  48         __u8                    reserved;
  49
  50         /* Protocol, addresses and port numbers */
  51         __u8                    protocol;       /* Which protocol (TCP/UDP) */
  52         __be16                  cport;
  53         __be16                  vport;
  54         __be16                  dport;
  55         __be32                  caddr;          /* client address */
  56         __be32                  vaddr;          /* virtual address */
  57         __be32                  daddr;          /* destination address */
  58
  59         /* Flags and state transition */
  60         __be16                  flags;          /* status flags */
  61         __be16                  state;          /* state info */
  62
  63         /* The sequence options start here */
  64 };
  65
  66 struct ip_vs_sync_conn_options {
  67         struct ip_vs_seq        in_seq;         /* incoming seq. struct */
  68         struct ip_vs_seq        out_seq;        /* outgoing seq. struct */
  69 };
  70
  71 struct ip_vs_sync_thread_data {
  72         struct socket *sock;
  73         char *buf;
  74 };
  75
  76 #define SIMPLE_CONN_SIZE  (sizeof(struct ip_vs_sync_conn))
  77 #define FULL_CONN_SIZE  \
  78 (sizeof(struct ip_vs_sync_conn) + sizeof(struct ip_vs_sync_conn_options))
  79
  80
  81 /*
  82   The master mulitcasts messages to the backup load balancers in the
  83   following format.
  84
  85        0                   1                   2                   3
  86        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  87       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88       |  Count Conns  |    SyncID     |            Size               |
  89       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90       |                                                               |
  91       |                    IPVS Sync Connection (1)                   |
  92       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93       |                            .                                  |
  94       |                            .                                  |
  95       |                            .                                  |
  96       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  97       |                                                               |
  98       |                    IPVS Sync Connection (n)                   |
  99       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 100 */
 101
 102 #define SYNC_MESG_HEADER_LEN    4
 103 #define MAX_CONNS_PER_SYNCBUFF  255 /* nr_conns in ip_vs_sync_mesg is 8 bit */
 104
 105 struct ip_vs_sync_mesg {
 106         __u8                    nr_conns;
 107         __u8                    syncid;
 108         __u16                   size;
 109
 110         /* ip_vs_sync_conn entries start here */
 111 };
 112
 113 /* the maximum length of sync (sending/receiving) message */
 114 static int sync_send_mesg_maxlen;
 115 static int sync_recv_mesg_maxlen;
 116
 117 struct ip_vs_sync_buff {
 118         struct list_head        list;
 119         unsigned long           firstuse;
 120
 121         /* pointers for the message data */
 122         struct ip_vs_sync_mesg  *mesg;
 123         unsigned char           *head;
 124         unsigned char           *end;
 125 };
 126
 127
 128 /* the sync_buff list head and the lock */
 129 static LIST_HEAD(ip_vs_sync_queue);
 130 static DEFINE_SPINLOCK(ip_vs_sync_lock);
 131
 132 /* current sync_buff for accepting new conn entries */
 133 static struct ip_vs_sync_buff   *curr_sb = NULL;
 134 static DEFINE_SPINLOCK(curr_sb_lock);
 135
 136 /* ipvs sync daemon state */
 137 volatile int ip_vs_sync_state = IP_VS_STATE_NONE;
 138 volatile int ip_vs_master_syncid = 0;
 139 volatile int ip_vs_backup_syncid = 0;
 140
 141 /* multicast interface name */
 142 char ip_vs_master_mcast_ifn[IP_VS_IFNAME_MAXLEN];
 143 char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
 144
 145 /* sync daemon tasks */
 146 static struct task_struct *sync_master_thread;
 147 static struct task_struct *sync_backup_thread;
 148
 149 /* multicast addr */
 150 static struct sockaddr_in mcast_addr = {
 151         .sin_family             = AF_INET,
 152         .sin_port               = __constant_htons(IP_VS_SYNC_PORT),
 153         .sin_addr.s_addr        = __constant_htonl(IP_VS_SYNC_GROUP),
 154 };
 155
 156
 157 static inline struct ip_vs_sync_buff *sb_dequeue(void)
 158 {
 159         struct ip_vs_sync_buff *sb;
 160
 161         spin_lock_bh(&ip_vs_sync_lock);
 162         if (list_empty(&ip_vs_sync_queue)) {
 163                 sb = NULL;
 164         } else {
 165                 sb = list_entry(ip_vs_sync_queue.next,
 166                                 struct ip_vs_sync_buff,
 167                                 list);
 168                 list_del(&sb->list);
 169         }
 170         spin_unlock_bh(&ip_vs_sync_lock);
 171
 172         return sb;
 173 }
 174
 175 static inline struct ip_vs_sync_buff * ip_vs_sync_buff_create(void)
 176 {
 177         struct ip_vs_sync_buff *sb;
 178
 179         if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
 180                 return NULL;
 181
 182         if (!(sb->mesg=kmalloc(sync_send_mesg_maxlen, GFP_ATOMIC))) {
 183                 kfree(sb);
 184                 return NULL;
 185         }
 186         sb->mesg->nr_conns = 0;
 187         sb->mesg->syncid = ip_vs_master_syncid;
 188         sb->mesg->size = 4;
 189         sb->head = (unsigned char *)sb->mesg + 4;
 190         sb->end = (unsigned char *)sb->mesg + sync_send_mesg_maxlen;
 191         sb->firstuse = jiffies;
 192         return sb;
 193 }
 194
 195 static inline void ip_vs_sync_buff_release(struct ip_vs_sync_buff *sb)
 196 {
 197         kfree(sb->mesg);
 198         kfree(sb);
 199 }
 200
 201 static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
 202 {
 203         spin_lock(&ip_vs_sync_lock);
 204         if (ip_vs_sync_state & IP_VS_STATE_MASTER)
 205                 list_add_tail(&sb->list, &ip_vs_sync_queue);
 206         else
 207                 ip_vs_sync_buff_release(sb);
 208         spin_unlock(&ip_vs_sync_lock);
 209 }
 210
 211 /*
 212  *      Get the current sync buffer if it has been created for more
 213  *      than the specified time or the specified time is zero.
 214  */
 215 static inline struct ip_vs_sync_buff *
 216 get_curr_sync_buff(unsigned long time)
 217 {
 218         struct ip_vs_sync_buff *sb;
 219
 220         spin_lock_bh(&curr_sb_lock);
 221         if (curr_sb && (time == 0 ||
 222                         time_before(jiffies - curr_sb->firstuse, time))) {
 223                 sb = curr_sb;
 224                 curr_sb = NULL;
 225         } else
 226                 sb = NULL;
 227         spin_unlock_bh(&curr_sb_lock);
 228         return sb;
 229 }
 230
 231
 232 /*
 233  *      Add an ip_vs_conn information into the current sync_buff.
 234  *      Called by ip_vs_in.
 235  */
 236 void ip_vs_sync_conn(struct ip_vs_conn *cp)
 237 {
 238         struct ip_vs_sync_mesg *m;
 239         struct ip_vs_sync_conn *s;
 240         int len;
 241
 242         spin_lock(&curr_sb_lock);
 243         if (!curr_sb) {
 244                 if (!(curr_sb=ip_vs_sync_buff_create())) {
 245                         spin_unlock(&curr_sb_lock);
 246                         IP_VS_ERR("ip_vs_sync_buff_create failed.\n");
 247                         return;
 248                 }
 249         }
 250
 251         len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
 252                 SIMPLE_CONN_SIZE;
 253         m = curr_sb->mesg;
 254         s = (struct ip_vs_sync_conn *)curr_sb->head;
 255
 256         /* copy members */
 257         s->protocol = cp->protocol;
 258         s->cport = cp->cport;
 259         s->vport = cp->vport;
 260         s->dport = cp->dport;
 261         s->caddr = cp->caddr.ip;
 262         s->vaddr = cp->vaddr.ip;
 263         s->daddr = cp->daddr.ip;
 264         s->flags = htons(cp->flags & ~IP_VS_CONN_F_HASHED);
 265         s->state = htons(cp->state);
 266         if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
 267                 struct ip_vs_sync_conn_options *opt =
 268                         (struct ip_vs_sync_conn_options *)&s[1];
 269                 memcpy(opt, &cp->in_seq, sizeof(*opt));
 270         }
 271
 272         m->nr_conns++;
 273         m->size += len;
 274         curr_sb->head += len;
 275
 276         /* check if there is a space for next one */
 277         if (curr_sb->head+FULL_CONN_SIZE > curr_sb->end) {
 278                 sb_queue_tail(curr_sb);
 279                 curr_sb = NULL;
 280         }
 281         spin_unlock(&curr_sb_lock);
 282
 283         /* synchronize its controller if it has */
 284         if (cp->control)
 285                 ip_vs_sync_conn(cp->control);
 286 }
 287
 288
 289 /*
 290  *      Process received multicast message and create the corresponding
 291  *      ip_vs_conn entries.
 292  */
 293 static void ip_vs_process_message(const char *buffer, const size_t buflen)
 294 {
 295         struct ip_vs_sync_mesg *m = (struct ip_vs_sync_mesg *)buffer;
 296         struct ip_vs_sync_conn *s;
 297         struct ip_vs_sync_conn_options *opt;
 298         struct ip_vs_conn *cp;
 299         struct ip_vs_protocol *pp;
 300         struct ip_vs_dest *dest;
 301         char *p;
 302         int i;
 303
 304         if (buflen < sizeof(struct ip_vs_sync_mesg)) {
 305                 IP_VS_ERR_RL("sync message header too short\n");
 306                 return;
 307         }
 308
 309         /* Convert size back to host byte order */
 310         m->size = ntohs(m->size);
 311
 312         if (buflen != m->size) {
 313                 IP_VS_ERR_RL("bogus sync message size\n");
 314                 return;
 315         }
 316
 317         /* SyncID sanity check */
 318         if (ip_vs_backup_syncid != 0 && m->syncid != ip_vs_backup_syncid) {
 319                 IP_VS_DBG(7, "Ignoring incoming msg with syncid = %d\n",
 320                           m->syncid);
 321                 return;
 322         }
 323
 324         p = (char *)buffer + sizeof(struct ip_vs_sync_mesg);
 325         for (i=0; i<m->nr_conns; i++) {
 326                 unsigned flags, state;
 327
 328                 if (p + SIMPLE_CONN_SIZE > buffer+buflen) {
 329                         IP_VS_ERR_RL("bogus conn in sync message\n");
 330                         return;
 331                 }
 332                 s = (struct ip_vs_sync_conn *) p;
 333                 flags = ntohs(s->flags) | IP_VS_CONN_F_SYNC;
 334                 flags &= ~IP_VS_CONN_F_HASHED;
 335                 if (flags & IP_VS_CONN_F_SEQ_MASK) {
 336                         opt = (struct ip_vs_sync_conn_options *)&s[1];
 337                         p += FULL_CONN_SIZE;
 338                         if (p > buffer+buflen) {
 339                                 IP_VS_ERR_RL("bogus conn options in sync message\n");
 340                                 return;
 341                         }
 342                 } else {
 343                         opt = NULL;
 344                         p += SIMPLE_CONN_SIZE;
 345                 }
 346
 347                 state = ntohs(s->state);
 348                 if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
 349                         pp = ip_vs_proto_get(s->protocol);
 350                         if (!pp) {
 351                                 IP_VS_ERR_RL("Unsupported protocol %u in sync msg\n",
 352                                         s->protocol);
 353                                 continue;
 354                         }
 355                         if (state >= pp->num_states) {
 356                                 IP_VS_DBG(2, "Invalid %s state %u in sync msg\n",
 357                                         pp->name, state);
 358                                 continue;
 359                         }
 360                 } else {
 361                         /* protocol in templates is not used for state/timeout */
 362                         pp = NULL;
 363                         if (state > 0) {
 364                                 IP_VS_DBG(2, "Invalid template state %u in sync msg\n",
 365                                         state);
 366                                 state = 0;
 367                         }
 368                 }
 369
 370                 if (!(flags & IP_VS_CONN_F_TEMPLATE))
 371                         cp = ip_vs_conn_in_get(AF_INET, s->protocol,
 372                                                (union nf_inet_addr *)&s->caddr,
 373                                                s->cport,
 374                                                (union nf_inet_addr *)&s->vaddr,
 375                                                s->vport);
 376                 else
 377                         cp = ip_vs_ct_in_get(AF_INET, s->protocol,
 378                                              (union nf_inet_addr *)&s->caddr,
 379                                              s->cport,
 380                                              (union nf_inet_addr *)&s->vaddr,
 381                                              s->vport);
 382                 if (!cp) {
 383                         /*
 384                          * Find the appropriate destination for the connection.
 385                          * If it is not found the connection will remain unbound
 386                          * but still handled.
 387                          */
 388                         dest = ip_vs_find_dest(AF_INET,
 389                                                (union nf_inet_addr *)&s->daddr,
 390                                                s->dport,
 391                                                (union nf_inet_addr *)&s->vaddr,
 392                                                s->vport,
 393                                                s->protocol);
 394                         /*  Set the approprite ativity flag */
 395                         if (s->protocol == IPPROTO_TCP) {
 396                                 if (state != IP_VS_TCP_S_ESTABLISHED)
 397                                         flags |= IP_VS_CONN_F_INACTIVE;
 398                                 else
 399                                         flags &= ~IP_VS_CONN_F_INACTIVE;
 400                         }
 401                         cp = ip_vs_conn_new(AF_INET, s->protocol,
 402                                             (union nf_inet_addr *)&s->caddr,
 403                                             s->cport,
 404                                             (union nf_inet_addr *)&s->vaddr,
 405                                             s->vport,
 406                                             (union nf_inet_addr *)&s->daddr,
 407                                             s->dport,
 408                                             flags, dest);
 409                         if (dest)
 410                                 atomic_dec(&dest->refcnt);
 411                         if (!cp) {
 412                                 IP_VS_ERR("ip_vs_conn_new failed\n");
 413                                 return;
 414                         }
 415                 } else if (!cp->dest) {
 416                         dest = ip_vs_try_bind_dest(cp);
 417                         if (dest)
 418                                 atomic_dec(&dest->refcnt);
 419                 } else if ((cp->dest) && (cp->protocol == IPPROTO_TCP) &&
 420                            (cp->state != state)) {
 421                         /* update active/inactive flag for the connection */
 422                         dest = cp->dest;
 423                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 424                                 (state != IP_VS_TCP_S_ESTABLISHED)) {
 425                                 atomic_dec(&dest->activeconns);
 426                                 atomic_inc(&dest->inactconns);
 427                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
 428                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 429                                 (state == IP_VS_TCP_S_ESTABLISHED)) {
 430                                 atomic_inc(&dest->activeconns);
 431                                 atomic_dec(&dest->inactconns);
 432                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 433                         }
 434                 }
 435
 436                 if (opt)
 437                         memcpy(&cp->in_seq, opt, sizeof(*opt));
 438                 atomic_set(&cp->in_pkts, sysctl_ip_vs_sync_threshold[0]);
 439                 cp->state = state;
 440                 cp->old_state = cp->state;
 441                 /*
 442                  * We can not recover the right timeout for templates
 443                  * in all cases, we can not find the right fwmark
 444                  * virtual service. If needed, we can do it for
 445                  * non-fwmark persistent services.
 446                  */
 447                 if (!(flags & IP_VS_CONN_F_TEMPLATE) && pp->timeout_table)
 448                         cp->timeout = pp->timeout_table[state];
 449                 else
 450                         cp->timeout = (3*60*HZ);
 451                 ip_vs_conn_put(cp);
 452         }
 453 }
 454
 455
 456 /*
 457  *      Setup loopback of outgoing multicasts on a sending socket
 458  */
 459 static void set_mcast_loop(struct sock *sk, u_char loop)
 460 {
 461         struct inet_sock *inet = inet_sk(sk);
 462
 463         /* setsockopt(sock, SOL_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); */
 464         lock_sock(sk);
 465         inet->mc_loop = loop ? 1 : 0;
 466         release_sock(sk);
 467 }
 468
 469 /*
 470  *      Specify TTL for outgoing multicasts on a sending socket
 471  */
 472 static void set_mcast_ttl(struct sock *sk, u_char ttl)
 473 {
 474         struct inet_sock *inet = inet_sk(sk);
 475
 476         /* setsockopt(sock, SOL_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); */
 477         lock_sock(sk);
 478         inet->mc_ttl = ttl;
 479         release_sock(sk);
 480 }
 481
 482 /*
 483  *      Specifiy default interface for outgoing multicasts
 484  */
 485 static int set_mcast_if(struct sock *sk, char *ifname)
 486 {
 487         struct net_device *dev;
 488         struct inet_sock *inet = inet_sk(sk);
 489
 490         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
 491                 return -ENODEV;
 492
 493         if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
 494                 return -EINVAL;
 495
 496         lock_sock(sk);
 497         inet->mc_index = dev->ifindex;
 498         /*  inet->mc_addr  = 0; */
 499         release_sock(sk);
 500
 501         return 0;
 502 }
 503
 504
 505 /*
 506  *      Set the maximum length of sync message according to the
 507  *      specified interface's MTU.
 508  */
 509 static int set_sync_mesg_maxlen(int sync_state)
 510 {
 511         struct net_device *dev;
 512         int num;
 513
 514         if (sync_state == IP_VS_STATE_MASTER) {
 515                 if ((dev = __dev_get_by_name(&init_net, ip_vs_master_mcast_ifn)) == NULL)
 516                         return -ENODEV;
 517
 518                 num = (dev->mtu - sizeof(struct iphdr) -
 519                        sizeof(struct udphdr) -
 520                        SYNC_MESG_HEADER_LEN - 20) / SIMPLE_CONN_SIZE;
 521                 sync_send_mesg_maxlen = SYNC_MESG_HEADER_LEN +
 522                         SIMPLE_CONN_SIZE * min(num, MAX_CONNS_PER_SYNCBUFF);
 523                 IP_VS_DBG(7, "setting the maximum length of sync sending "
 524                           "message %d.\n", sync_send_mesg_maxlen);
 525         } else if (sync_state == IP_VS_STATE_BACKUP) {
 526                 if ((dev = __dev_get_by_name(&init_net, ip_vs_backup_mcast_ifn)) == NULL)
 527                         return -ENODEV;
 528
 529                 sync_recv_mesg_maxlen = dev->mtu -
 530                         sizeof(struct iphdr) - sizeof(struct udphdr);
 531                 IP_VS_DBG(7, "setting the maximum length of sync receiving "
 532                           "message %d.\n", sync_recv_mesg_maxlen);
 533         }
 534
 535         return 0;
 536 }
 537
 538
 539 /*
 540  *      Join a multicast group.
 541  *      the group is specified by a class D multicast address 224.0.0.0/8
 542  *      in the in_addr structure passed in as a parameter.
 543  */
 544 static int
 545 join_mcast_group(struct sock *sk, struct in_addr *addr, char *ifname)
 546 {
 547         struct ip_mreqn mreq;
 548         struct net_device *dev;
 549         int ret;
 550
 551         memset(&mreq, 0, sizeof(mreq));
 552         memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));
 553
 554         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
 555                 return -ENODEV;
 556         if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
 557                 return -EINVAL;
 558
 559         mreq.imr_ifindex = dev->ifindex;
 560
 561         lock_sock(sk);
 562         ret = ip_mc_join_group(sk, &mreq);
 563         release_sock(sk);
 564
 565         return ret;
 566 }
 567
 568
 569 static int bind_mcastif_addr(struct socket *sock, char *ifname)
 570 {
 571         struct net_device *dev;
 572         __be32 addr;
 573         struct sockaddr_in sin;
 574
 575         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
 576                 return -ENODEV;
 577
 578         addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
 579         if (!addr)
 580                 IP_VS_ERR("You probably need to specify IP address on "
 581                           "multicast interface.\n");
 582
 583         IP_VS_DBG(7, "binding socket with (%s) %pI4\n",
 584                   ifname, &addr);
 585
 586         /* Now bind the socket with the address of multicast interface */
 587         sin.sin_family       = AF_INET;
 588         sin.sin_addr.s_addr  = addr;
 589         sin.sin_port         = 0;
 590
 591         return sock->ops->bind(sock, (struct sockaddr*)&sin, sizeof(sin));
 592 }
 593
 594 /*
 595  *      Set up sending multicast socket over UDP
 596  */
 597 static struct socket * make_send_sock(void)
 598 {
 599         struct socket *sock;
 600         int result;
 601
 602         /* First create a socket */
 603         result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
 604         if (result < 0) {
 605                 IP_VS_ERR("Error during creation of socket; terminating\n");
 606                 return ERR_PTR(result);
 607         }
 608
 609         result = set_mcast_if(sock->sk, ip_vs_master_mcast_ifn);
 610         if (result < 0) {
 611                 IP_VS_ERR("Error setting outbound mcast interface\n");
 612                 goto error;
 613         }
 614
 615         set_mcast_loop(sock->sk, 0);
 616         set_mcast_ttl(sock->sk, 1);
 617
 618         result = bind_mcastif_addr(sock, ip_vs_master_mcast_ifn);
 619         if (result < 0) {
 620                 IP_VS_ERR("Error binding address of the mcast interface\n");
 621                 goto error;
 622         }
 623
 624         result = sock->ops->connect(sock, (struct sockaddr *) &mcast_addr,
 625                         sizeof(struct sockaddr), 0);
 626         if (result < 0) {
 627                 IP_VS_ERR("Error connecting to the multicast addr\n");
 628                 goto error;
 629         }
 630
 631         return sock;
 632
 633   error:
 634         sock_release(sock);
 635         return ERR_PTR(result);
 636 }
 637
 638
 639 /*
 640  *      Set up receiving multicast socket over UDP
 641  */
 642 static struct socket * make_receive_sock(void)
 643 {
 644         struct socket *sock;
 645         int result;
 646
 647         /* First create a socket */
 648         result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
 649         if (result < 0) {
 650                 IP_VS_ERR("Error during creation of socket; terminating\n");
 651                 return ERR_PTR(result);
 652         }
 653
 654         /* it is equivalent to the REUSEADDR option in user-space */
 655         sock->sk->sk_reuse = 1;
 656
 657         result = sock->ops->bind(sock, (struct sockaddr *) &mcast_addr,
 658                         sizeof(struct sockaddr));
 659         if (result < 0) {
 660                 IP_VS_ERR("Error binding to the multicast addr\n");
 661                 goto error;
 662         }
 663
 664         /* join the multicast group */
 665         result = join_mcast_group(sock->sk,
 666                         (struct in_addr *) &mcast_addr.sin_addr,
 667                         ip_vs_backup_mcast_ifn);
 668         if (result < 0) {
 669                 IP_VS_ERR("Error joining to the multicast group\n");
 670                 goto error;
 671         }
 672
 673         return sock;
 674
 675   error:
 676         sock_release(sock);
 677         return ERR_PTR(result);
 678 }
 679
 680
 681 static int
 682 ip_vs_send_async(struct socket *sock, const char *buffer, const size_t length)
 683 {
 684         struct msghdr   msg = {.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL};
 685         struct kvec     iov;
 686         int             len;
 687
 688         EnterFunction(7);
 689         iov.iov_base     = (void *)buffer;
 690         iov.iov_len      = length;
 691
 692         len = kernel_sendmsg(sock, &msg, &iov, 1, (size_t)(length));
 693
 694         LeaveFunction(7);
 695         return len;
 696 }
 697
 698 static void
 699 ip_vs_send_sync_msg(struct socket *sock, struct ip_vs_sync_mesg *msg)
 700 {
 701         int msize;
 702
 703         msize = msg->size;
 704
 705         /* Put size in network byte order */
 706         msg->size = htons(msg->size);
 707
 708         if (ip_vs_send_async(sock, (char *)msg, msize) != msize)
 709                 IP_VS_ERR("ip_vs_send_async error\n");
 710 }
 711
 712 static int
 713 ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
 714 {
 715         struct msghdr           msg = {NULL,};
 716         struct kvec             iov;
 717         int                     len;
 718
 719         EnterFunction(7);
 720
 721         /* Receive a packet */
 722         iov.iov_base     = buffer;
 723         iov.iov_len      = (size_t)buflen;
 724
 725         len = kernel_recvmsg(sock, &msg, &iov, 1, buflen, 0);
 726
 727         if (len < 0)
 728                 return -1;
 729
 730         LeaveFunction(7);
 731         return len;
 732 }
 733
 734
 735 static int sync_thread_master(void *data)
 736 {
 737         struct ip_vs_sync_thread_data *tinfo = data;
 738         struct ip_vs_sync_buff *sb;
 739
 740         IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
 741                    "syncid = %d\n",
 742                    ip_vs_master_mcast_ifn, ip_vs_master_syncid);
 743
 744         while (!kthread_should_stop()) {
 745                 while ((sb = sb_dequeue())) {
 746                         ip_vs_send_sync_msg(tinfo->sock, sb->mesg);
 747                         ip_vs_sync_buff_release(sb);
 748                 }
 749
 750                 /* check if entries stay in curr_sb for 2 seconds */
 751                 sb = get_curr_sync_buff(2 * HZ);
 752                 if (sb) {
 753                         ip_vs_send_sync_msg(tinfo->sock, sb->mesg);
 754                         ip_vs_sync_buff_release(sb);
 755                 }
 756
 757                 schedule_timeout_interruptible(HZ);
 758         }
 759
 760         /* clean up the sync_buff queue */
 761         while ((sb=sb_dequeue())) {
 762                 ip_vs_sync_buff_release(sb);
 763         }
 764
 765         /* clean up the current sync_buff */
 766         if ((sb = get_curr_sync_buff(0))) {
 767                 ip_vs_sync_buff_release(sb);
 768         }
 769
 770         /* release the sending multicast socket */
 771         sock_release(tinfo->sock);
 772         kfree(tinfo);
 773
 774         return 0;
 775 }
 776
 777
 778 static int sync_thread_backup(void *data)
 779 {
 780         struct ip_vs_sync_thread_data *tinfo = data;
 781         int len;
 782
 783         IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
 784                    "syncid = %d\n",
 785                    ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
 786
 787         while (!kthread_should_stop()) {
 788                 wait_event_interruptible(*tinfo->sock->sk->sk_sleep,
 789                          !skb_queue_empty(&tinfo->sock->sk->sk_receive_queue)
 790                          || kthread_should_stop());
 791
 792                 /* do we have data now? */
 793                 while (!skb_queue_empty(&(tinfo->sock->sk->sk_receive_queue))) {
 794                         len = ip_vs_receive(tinfo->sock, tinfo->buf,
 795                                         sync_recv_mesg_maxlen);
 796                         if (len <= 0) {
 797                                 IP_VS_ERR("receiving message error\n");
 798                                 break;
 799                         }
 800
 801                         /* disable bottom half, because it accesses the data
 802                            shared by softirq while getting/creating conns */
 803                         local_bh_disable();
 804                         ip_vs_process_message(tinfo->buf, len);
 805                         local_bh_enable();
 806                 }
 807         }
 808
 809         /* release the sending multicast socket */
 810         sock_release(tinfo->sock);
 811         kfree(tinfo->buf);
 812         kfree(tinfo);
 813
 814         return 0;
 815 }
 816
 817
 818 int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
 819 {
 820         struct ip_vs_sync_thread_data *tinfo;
 821         struct task_struct **realtask, *task;
 822         struct socket *sock;
 823         char *name, *buf = NULL;
 824         int (*threadfn)(void *data);
 825         int result = -ENOMEM;
 826
 827         IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
 828         IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %Zd bytes\n",
 829                   sizeof(struct ip_vs_sync_conn));
 830
 831         if (state == IP_VS_STATE_MASTER) {
 832                 if (sync_master_thread)
 833                         return -EEXIST;
 834
 835                 strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
 836                         sizeof(ip_vs_master_mcast_ifn));
 837                 ip_vs_master_syncid = syncid;
 838                 realtask = &sync_master_thread;
 839                 name = "ipvs_syncmaster";
 840                 threadfn = sync_thread_master;
 841                 sock = make_send_sock();
 842         } else if (state == IP_VS_STATE_BACKUP) {
 843                 if (sync_backup_thread)
 844                         return -EEXIST;
 845
 846                 strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
 847                         sizeof(ip_vs_backup_mcast_ifn));
 848                 ip_vs_backup_syncid = syncid;
 849                 realtask = &sync_backup_thread;
 850                 name = "ipvs_syncbackup";
 851                 threadfn = sync_thread_backup;
 852                 sock = make_receive_sock();
 853         } else {
 854                 return -EINVAL;
 855         }
 856
 857         if (IS_ERR(sock)) {
 858                 result = PTR_ERR(sock);
 859                 goto out;
 860         }
 861
 862         set_sync_mesg_maxlen(state);
 863         if (state == IP_VS_STATE_BACKUP) {
 864                 buf = kmalloc(sync_recv_mesg_maxlen, GFP_KERNEL);
 865                 if (!buf)
 866                         goto outsocket;
 867         }
 868
 869         tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL);
 870         if (!tinfo)
 871                 goto outbuf;
 872
 873         tinfo->sock = sock;
 874         tinfo->buf = buf;
 875
 876         task = kthread_run(threadfn, tinfo, name);
 877         if (IS_ERR(task)) {
 878                 result = PTR_ERR(task);
 879                 goto outtinfo;
 880         }
 881
 882         /* mark as active */
 883         *realtask = task;
 884         ip_vs_sync_state |= state;
 885
 886         /* increase the module use count */
 887         ip_vs_use_count_inc();
 888
 889         return 0;
 890
 891 outtinfo:
 892         kfree(tinfo);
 893 outbuf:
 894         kfree(buf);
 895 outsocket:
 896         sock_release(sock);
 897 out:
 898         return result;
 899 }
 900
 901
 902 int stop_sync_thread(int state)
 903 {
 904         IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
 905
 906         if (state == IP_VS_STATE_MASTER) {
 907                 if (!sync_master_thread)
 908                         return -ESRCH;
 909
 910                 IP_VS_INFO("stopping master sync thread %d ...\n",
 911                            task_pid_nr(sync_master_thread));
 912
 913                 /*
 914                  * The lock synchronizes with sb_queue_tail(), so that we don't
 915                  * add sync buffers to the queue, when we are already in
 916                  * progress of stopping the master sync daemon.
 917                  */
 918
 919                 spin_lock_bh(&ip_vs_sync_lock);
 920                 ip_vs_sync_state &= ~IP_VS_STATE_MASTER;
 921                 spin_unlock_bh(&ip_vs_sync_lock);
 922                 kthread_stop(sync_master_thread);
 923                 sync_master_thread = NULL;
 924         } else if (state == IP_VS_STATE_BACKUP) {
 925                 if (!sync_backup_thread)
 926                         return -ESRCH;
 927
 928                 IP_VS_INFO("stopping backup sync thread %d ...\n",
 929                            task_pid_nr(sync_backup_thread));
 930
 931                 ip_vs_sync_state &= ~IP_VS_STATE_BACKUP;
 932                 kthread_stop(sync_backup_thread);
 933                 sync_backup_thread = NULL;
 934         } else {
 935                 return -EINVAL;
 936         }
 937
 938         /* decrease the module use count */
 939         ip_vs_use_count_dec();
 940
 941         return 0;
 942 }