ipvs: fix oops in backup for fwmark conn templates
[linux-2.6.git] / net / ipv4 / 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  * Version:     $Id: ip_vs_sync.c,v 1.13 2003/06/08 09:31:19 wensong Exp $
9  *
10  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
11  *
12  * ip_vs_sync:  sync connection info from master load balancer to backups
13  *              through multicast
14  *
15  * Changes:
16  *      Alexandre Cassen        :       Added master & backup support at a time.
17  *      Alexandre Cassen        :       Added SyncID support for incoming sync
18  *                                      messages filtering.
19  *      Justin Ossevoort        :       Fix endian problem on sync message size.
20  */
21
22 #include <linux/module.h>
23 #include <linux/slab.h>
24 #include <linux/inetdevice.h>
25 #include <linux/net.h>
26 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/skbuff.h>
29 #include <linux/in.h>
30 #include <linux/igmp.h>                 /* for ip_mc_join_group */
31 #include <linux/udp.h>
32
33 #include <net/ip.h>
34 #include <net/sock.h>
35 #include <asm/uaccess.h>                /* for get_fs and set_fs */
36
37 #include <net/ip_vs.h>
38
39 #define IP_VS_SYNC_GROUP 0xe0000051    /* multicast addr - 224.0.0.81 */
40 #define IP_VS_SYNC_PORT  8848          /* multicast port */
41
42
43 /*
44  *      IPVS sync connection entry
45  */
46 struct ip_vs_sync_conn {
47         __u8                    reserved;
48
49         /* Protocol, addresses and port numbers */
50         __u8                    protocol;       /* Which protocol (TCP/UDP) */
51         __be16                  cport;
52         __be16                  vport;
53         __be16                  dport;
54         __be32                  caddr;          /* client address */
55         __be32                  vaddr;          /* virtual address */
56         __be32                  daddr;          /* destination address */
57
58         /* Flags and state transition */
59         __be16                  flags;          /* status flags */
60         __be16                  state;          /* state info */
61
62         /* The sequence options start here */
63 };
64
65 struct ip_vs_sync_conn_options {
66         struct ip_vs_seq        in_seq;         /* incoming seq. struct */
67         struct ip_vs_seq        out_seq;        /* outgoing seq. struct */
68 };
69
70 struct ip_vs_sync_thread_data {
71         struct completion *startup;
72         int state;
73 };
74
75 #define SIMPLE_CONN_SIZE  (sizeof(struct ip_vs_sync_conn))
76 #define FULL_CONN_SIZE  \
77 (sizeof(struct ip_vs_sync_conn) + sizeof(struct ip_vs_sync_conn_options))
78
79
80 /*
81   The master mulitcasts messages to the backup load balancers in the
82   following format.
83
84        0                   1                   2                   3
85        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
86       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
87       |  Count Conns  |    SyncID     |            Size               |
88       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
89       |                                                               |
90       |                    IPVS Sync Connection (1)                   |
91       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
92       |                            .                                  |
93       |                            .                                  |
94       |                            .                                  |
95       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
96       |                                                               |
97       |                    IPVS Sync Connection (n)                   |
98       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
99 */
100
101 #define SYNC_MESG_HEADER_LEN    4
102
103 struct ip_vs_sync_mesg {
104         __u8                    nr_conns;
105         __u8                    syncid;
106         __u16                   size;
107
108         /* ip_vs_sync_conn entries start here */
109 };
110
111 /* the maximum length of sync (sending/receiving) message */
112 static int sync_send_mesg_maxlen;
113 static int sync_recv_mesg_maxlen;
114
115 struct ip_vs_sync_buff {
116         struct list_head        list;
117         unsigned long           firstuse;
118
119         /* pointers for the message data */
120         struct ip_vs_sync_mesg  *mesg;
121         unsigned char           *head;
122         unsigned char           *end;
123 };
124
125
126 /* the sync_buff list head and the lock */
127 static LIST_HEAD(ip_vs_sync_queue);
128 static DEFINE_SPINLOCK(ip_vs_sync_lock);
129
130 /* current sync_buff for accepting new conn entries */
131 static struct ip_vs_sync_buff   *curr_sb = NULL;
132 static DEFINE_SPINLOCK(curr_sb_lock);
133
134 /* ipvs sync daemon state */
135 volatile int ip_vs_sync_state = IP_VS_STATE_NONE;
136 volatile int ip_vs_master_syncid = 0;
137 volatile int ip_vs_backup_syncid = 0;
138
139 /* multicast interface name */
140 char ip_vs_master_mcast_ifn[IP_VS_IFNAME_MAXLEN];
141 char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
142
143 /* multicast addr */
144 static struct sockaddr_in mcast_addr;
145
146
147 static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
148 {
149         spin_lock(&ip_vs_sync_lock);
150         list_add_tail(&sb->list, &ip_vs_sync_queue);
151         spin_unlock(&ip_vs_sync_lock);
152 }
153
154 static inline struct ip_vs_sync_buff * sb_dequeue(void)
155 {
156         struct ip_vs_sync_buff *sb;
157
158         spin_lock_bh(&ip_vs_sync_lock);
159         if (list_empty(&ip_vs_sync_queue)) {
160                 sb = NULL;
161         } else {
162                 sb = list_entry(ip_vs_sync_queue.next,
163                                 struct ip_vs_sync_buff,
164                                 list);
165                 list_del(&sb->list);
166         }
167         spin_unlock_bh(&ip_vs_sync_lock);
168
169         return sb;
170 }
171
172 static inline struct ip_vs_sync_buff * ip_vs_sync_buff_create(void)
173 {
174         struct ip_vs_sync_buff *sb;
175
176         if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
177                 return NULL;
178
179         if (!(sb->mesg=kmalloc(sync_send_mesg_maxlen, GFP_ATOMIC))) {
180                 kfree(sb);
181                 return NULL;
182         }
183         sb->mesg->nr_conns = 0;
184         sb->mesg->syncid = ip_vs_master_syncid;
185         sb->mesg->size = 4;
186         sb->head = (unsigned char *)sb->mesg + 4;
187         sb->end = (unsigned char *)sb->mesg + sync_send_mesg_maxlen;
188         sb->firstuse = jiffies;
189         return sb;
190 }
191
192 static inline void ip_vs_sync_buff_release(struct ip_vs_sync_buff *sb)
193 {
194         kfree(sb->mesg);
195         kfree(sb);
196 }
197
198 /*
199  *      Get the current sync buffer if it has been created for more
200  *      than the specified time or the specified time is zero.
201  */
202 static inline struct ip_vs_sync_buff *
203 get_curr_sync_buff(unsigned long time)
204 {
205         struct ip_vs_sync_buff *sb;
206
207         spin_lock_bh(&curr_sb_lock);
208         if (curr_sb && (time == 0 ||
209                         time_before(jiffies - curr_sb->firstuse, time))) {
210                 sb = curr_sb;
211                 curr_sb = NULL;
212         } else
213                 sb = NULL;
214         spin_unlock_bh(&curr_sb_lock);
215         return sb;
216 }
217
218
219 /*
220  *      Add an ip_vs_conn information into the current sync_buff.
221  *      Called by ip_vs_in.
222  */
223 void ip_vs_sync_conn(struct ip_vs_conn *cp)
224 {
225         struct ip_vs_sync_mesg *m;
226         struct ip_vs_sync_conn *s;
227         int len;
228
229         spin_lock(&curr_sb_lock);
230         if (!curr_sb) {
231                 if (!(curr_sb=ip_vs_sync_buff_create())) {
232                         spin_unlock(&curr_sb_lock);
233                         IP_VS_ERR("ip_vs_sync_buff_create failed.\n");
234                         return;
235                 }
236         }
237
238         len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
239                 SIMPLE_CONN_SIZE;
240         m = curr_sb->mesg;
241         s = (struct ip_vs_sync_conn *)curr_sb->head;
242
243         /* copy members */
244         s->protocol = cp->protocol;
245         s->cport = cp->cport;
246         s->vport = cp->vport;
247         s->dport = cp->dport;
248         s->caddr = cp->caddr;
249         s->vaddr = cp->vaddr;
250         s->daddr = cp->daddr;
251         s->flags = htons(cp->flags & ~IP_VS_CONN_F_HASHED);
252         s->state = htons(cp->state);
253         if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
254                 struct ip_vs_sync_conn_options *opt =
255                         (struct ip_vs_sync_conn_options *)&s[1];
256                 memcpy(opt, &cp->in_seq, sizeof(*opt));
257         }
258
259         m->nr_conns++;
260         m->size += len;
261         curr_sb->head += len;
262
263         /* check if there is a space for next one */
264         if (curr_sb->head+FULL_CONN_SIZE > curr_sb->end) {
265                 sb_queue_tail(curr_sb);
266                 curr_sb = NULL;
267         }
268         spin_unlock(&curr_sb_lock);
269
270         /* synchronize its controller if it has */
271         if (cp->control)
272                 ip_vs_sync_conn(cp->control);
273 }
274
275
276 /*
277  *      Process received multicast message and create the corresponding
278  *      ip_vs_conn entries.
279  */
280 static void ip_vs_process_message(const char *buffer, const size_t buflen)
281 {
282         struct ip_vs_sync_mesg *m = (struct ip_vs_sync_mesg *)buffer;
283         struct ip_vs_sync_conn *s;
284         struct ip_vs_sync_conn_options *opt;
285         struct ip_vs_conn *cp;
286         struct ip_vs_protocol *pp;
287         struct ip_vs_dest *dest;
288         char *p;
289         int i;
290
291         if (buflen < sizeof(struct ip_vs_sync_mesg)) {
292                 IP_VS_ERR_RL("sync message header too short\n");
293                 return;
294         }
295
296         /* Convert size back to host byte order */
297         m->size = ntohs(m->size);
298
299         if (buflen != m->size) {
300                 IP_VS_ERR_RL("bogus sync message size\n");
301                 return;
302         }
303
304         /* SyncID sanity check */
305         if (ip_vs_backup_syncid != 0 && m->syncid != ip_vs_backup_syncid) {
306                 IP_VS_DBG(7, "Ignoring incoming msg with syncid = %d\n",
307                           m->syncid);
308                 return;
309         }
310
311         p = (char *)buffer + sizeof(struct ip_vs_sync_mesg);
312         for (i=0; i<m->nr_conns; i++) {
313                 unsigned flags, state;
314
315                 if (p + SIMPLE_CONN_SIZE > buffer+buflen) {
316                         IP_VS_ERR_RL("bogus conn in sync message\n");
317                         return;
318                 }
319                 s = (struct ip_vs_sync_conn *) p;
320                 flags = ntohs(s->flags) | IP_VS_CONN_F_SYNC;
321                 flags &= ~IP_VS_CONN_F_HASHED;
322                 if (flags & IP_VS_CONN_F_SEQ_MASK) {
323                         opt = (struct ip_vs_sync_conn_options *)&s[1];
324                         p += FULL_CONN_SIZE;
325                         if (p > buffer+buflen) {
326                                 IP_VS_ERR_RL("bogus conn options in sync message\n");
327                                 return;
328                         }
329                 } else {
330                         opt = NULL;
331                         p += SIMPLE_CONN_SIZE;
332                 }
333
334                 state = ntohs(s->state);
335                 if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
336                         pp = ip_vs_proto_get(s->protocol);
337                         if (!pp) {
338                                 IP_VS_ERR_RL("Unsupported protocol %u in sync msg\n",
339                                         s->protocol);
340                                 continue;
341                         }
342                         if (state >= pp->num_states) {
343                                 IP_VS_DBG(2, "Invalid %s state %u in sync msg\n",
344                                         pp->name, state);
345                                 continue;
346                         }
347                 } else {
348                         /* protocol in templates is not used for state/timeout */
349                         pp = NULL;
350                         if (state > 0) {
351                                 IP_VS_DBG(2, "Invalid template state %u in sync msg\n",
352                                         state);
353                                 state = 0;
354                         }
355                 }
356
357                 if (!(flags & IP_VS_CONN_F_TEMPLATE))
358                         cp = ip_vs_conn_in_get(s->protocol,
359                                                s->caddr, s->cport,
360                                                s->vaddr, s->vport);
361                 else
362                         cp = ip_vs_ct_in_get(s->protocol,
363                                                s->caddr, s->cport,
364                                                s->vaddr, s->vport);
365                 if (!cp) {
366                         /*
367                          * Find the appropriate destination for the connection.
368                          * If it is not found the connection will remain unbound
369                          * but still handled.
370                          */
371                         dest = ip_vs_find_dest(s->daddr, s->dport,
372                                                s->vaddr, s->vport,
373                                                s->protocol);
374                         /*  Set the approprite ativity flag */
375                         if (s->protocol == IPPROTO_TCP) {
376                                 if (state != IP_VS_TCP_S_ESTABLISHED)
377                                         flags |= IP_VS_CONN_F_INACTIVE;
378                                 else
379                                         flags &= ~IP_VS_CONN_F_INACTIVE;
380                         }
381                         cp = ip_vs_conn_new(s->protocol,
382                                             s->caddr, s->cport,
383                                             s->vaddr, s->vport,
384                                             s->daddr, s->dport,
385                                             flags, dest);
386                         if (dest)
387                                 atomic_dec(&dest->refcnt);
388                         if (!cp) {
389                                 IP_VS_ERR("ip_vs_conn_new failed\n");
390                                 return;
391                         }
392                 } else if (!cp->dest) {
393                         dest = ip_vs_try_bind_dest(cp);
394                         if (dest)
395                                 atomic_dec(&dest->refcnt);
396                 } else if ((cp->dest) && (cp->protocol == IPPROTO_TCP) &&
397                            (cp->state != state)) {
398                         /* update active/inactive flag for the connection */
399                         dest = cp->dest;
400                         if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
401                                 (state != IP_VS_TCP_S_ESTABLISHED)) {
402                                 atomic_dec(&dest->activeconns);
403                                 atomic_inc(&dest->inactconns);
404                                 cp->flags |= IP_VS_CONN_F_INACTIVE;
405                         } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
406                                 (state == IP_VS_TCP_S_ESTABLISHED)) {
407                                 atomic_inc(&dest->activeconns);
408                                 atomic_dec(&dest->inactconns);
409                                 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
410                         }
411                 }
412
413                 if (opt)
414                         memcpy(&cp->in_seq, opt, sizeof(*opt));
415                 atomic_set(&cp->in_pkts, sysctl_ip_vs_sync_threshold[0]);
416                 cp->state = state;
417                 cp->old_state = cp->state;
418                 /*
419                  * We can not recover the right timeout for templates
420                  * in all cases, we can not find the right fwmark
421                  * virtual service. If needed, we can do it for
422                  * non-fwmark persistent services.
423                  */
424                 if (!(flags & IP_VS_CONN_F_TEMPLATE) && pp->timeout_table)
425                         cp->timeout = pp->timeout_table[state];
426                 else
427                         cp->timeout = (3*60*HZ);
428                 ip_vs_conn_put(cp);
429         }
430 }
431
432
433 /*
434  *      Setup loopback of outgoing multicasts on a sending socket
435  */
436 static void set_mcast_loop(struct sock *sk, u_char loop)
437 {
438         struct inet_sock *inet = inet_sk(sk);
439
440         /* setsockopt(sock, SOL_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); */
441         lock_sock(sk);
442         inet->mc_loop = loop ? 1 : 0;
443         release_sock(sk);
444 }
445
446 /*
447  *      Specify TTL for outgoing multicasts on a sending socket
448  */
449 static void set_mcast_ttl(struct sock *sk, u_char ttl)
450 {
451         struct inet_sock *inet = inet_sk(sk);
452
453         /* setsockopt(sock, SOL_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); */
454         lock_sock(sk);
455         inet->mc_ttl = ttl;
456         release_sock(sk);
457 }
458
459 /*
460  *      Specifiy default interface for outgoing multicasts
461  */
462 static int set_mcast_if(struct sock *sk, char *ifname)
463 {
464         struct net_device *dev;
465         struct inet_sock *inet = inet_sk(sk);
466
467         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
468                 return -ENODEV;
469
470         if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
471                 return -EINVAL;
472
473         lock_sock(sk);
474         inet->mc_index = dev->ifindex;
475         /*  inet->mc_addr  = 0; */
476         release_sock(sk);
477
478         return 0;
479 }
480
481
482 /*
483  *      Set the maximum length of sync message according to the
484  *      specified interface's MTU.
485  */
486 static int set_sync_mesg_maxlen(int sync_state)
487 {
488         struct net_device *dev;
489         int num;
490
491         if (sync_state == IP_VS_STATE_MASTER) {
492                 if ((dev = __dev_get_by_name(&init_net, ip_vs_master_mcast_ifn)) == NULL)
493                         return -ENODEV;
494
495                 num = (dev->mtu - sizeof(struct iphdr) -
496                        sizeof(struct udphdr) -
497                        SYNC_MESG_HEADER_LEN - 20) / SIMPLE_CONN_SIZE;
498                 sync_send_mesg_maxlen =
499                         SYNC_MESG_HEADER_LEN + SIMPLE_CONN_SIZE * num;
500                 IP_VS_DBG(7, "setting the maximum length of sync sending "
501                           "message %d.\n", sync_send_mesg_maxlen);
502         } else if (sync_state == IP_VS_STATE_BACKUP) {
503                 if ((dev = __dev_get_by_name(&init_net, ip_vs_backup_mcast_ifn)) == NULL)
504                         return -ENODEV;
505
506                 sync_recv_mesg_maxlen = dev->mtu -
507                         sizeof(struct iphdr) - sizeof(struct udphdr);
508                 IP_VS_DBG(7, "setting the maximum length of sync receiving "
509                           "message %d.\n", sync_recv_mesg_maxlen);
510         }
511
512         return 0;
513 }
514
515
516 /*
517  *      Join a multicast group.
518  *      the group is specified by a class D multicast address 224.0.0.0/8
519  *      in the in_addr structure passed in as a parameter.
520  */
521 static int
522 join_mcast_group(struct sock *sk, struct in_addr *addr, char *ifname)
523 {
524         struct ip_mreqn mreq;
525         struct net_device *dev;
526         int ret;
527
528         memset(&mreq, 0, sizeof(mreq));
529         memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));
530
531         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
532                 return -ENODEV;
533         if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
534                 return -EINVAL;
535
536         mreq.imr_ifindex = dev->ifindex;
537
538         lock_sock(sk);
539         ret = ip_mc_join_group(sk, &mreq);
540         release_sock(sk);
541
542         return ret;
543 }
544
545
546 static int bind_mcastif_addr(struct socket *sock, char *ifname)
547 {
548         struct net_device *dev;
549         __be32 addr;
550         struct sockaddr_in sin;
551
552         if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
553                 return -ENODEV;
554
555         addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
556         if (!addr)
557                 IP_VS_ERR("You probably need to specify IP address on "
558                           "multicast interface.\n");
559
560         IP_VS_DBG(7, "binding socket with (%s) %u.%u.%u.%u\n",
561                   ifname, NIPQUAD(addr));
562
563         /* Now bind the socket with the address of multicast interface */
564         sin.sin_family       = AF_INET;
565         sin.sin_addr.s_addr  = addr;
566         sin.sin_port         = 0;
567
568         return sock->ops->bind(sock, (struct sockaddr*)&sin, sizeof(sin));
569 }
570
571 /*
572  *      Set up sending multicast socket over UDP
573  */
574 static struct socket * make_send_sock(void)
575 {
576         struct socket *sock;
577
578         /* First create a socket */
579         if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
580                 IP_VS_ERR("Error during creation of socket; terminating\n");
581                 return NULL;
582         }
583
584         if (set_mcast_if(sock->sk, ip_vs_master_mcast_ifn) < 0) {
585                 IP_VS_ERR("Error setting outbound mcast interface\n");
586                 goto error;
587         }
588
589         set_mcast_loop(sock->sk, 0);
590         set_mcast_ttl(sock->sk, 1);
591
592         if (bind_mcastif_addr(sock, ip_vs_master_mcast_ifn) < 0) {
593                 IP_VS_ERR("Error binding address of the mcast interface\n");
594                 goto error;
595         }
596
597         if (sock->ops->connect(sock,
598                                (struct sockaddr*)&mcast_addr,
599                                sizeof(struct sockaddr), 0) < 0) {
600                 IP_VS_ERR("Error connecting to the multicast addr\n");
601                 goto error;
602         }
603
604         return sock;
605
606   error:
607         sock_release(sock);
608         return NULL;
609 }
610
611
612 /*
613  *      Set up receiving multicast socket over UDP
614  */
615 static struct socket * make_receive_sock(void)
616 {
617         struct socket *sock;
618
619         /* First create a socket */
620         if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
621                 IP_VS_ERR("Error during creation of socket; terminating\n");
622                 return NULL;
623         }
624
625         /* it is equivalent to the REUSEADDR option in user-space */
626         sock->sk->sk_reuse = 1;
627
628         if (sock->ops->bind(sock,
629                             (struct sockaddr*)&mcast_addr,
630                             sizeof(struct sockaddr)) < 0) {
631                 IP_VS_ERR("Error binding to the multicast addr\n");
632                 goto error;
633         }
634
635         /* join the multicast group */
636         if (join_mcast_group(sock->sk,
637                              (struct in_addr*)&mcast_addr.sin_addr,
638                              ip_vs_backup_mcast_ifn) < 0) {
639                 IP_VS_ERR("Error joining to the multicast group\n");
640                 goto error;
641         }
642
643         return sock;
644
645   error:
646         sock_release(sock);
647         return NULL;
648 }
649
650
651 static int
652 ip_vs_send_async(struct socket *sock, const char *buffer, const size_t length)
653 {
654         struct msghdr   msg = {.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL};
655         struct kvec     iov;
656         int             len;
657
658         EnterFunction(7);
659         iov.iov_base     = (void *)buffer;
660         iov.iov_len      = length;
661
662         len = kernel_sendmsg(sock, &msg, &iov, 1, (size_t)(length));
663
664         LeaveFunction(7);
665         return len;
666 }
667
668 static void
669 ip_vs_send_sync_msg(struct socket *sock, struct ip_vs_sync_mesg *msg)
670 {
671         int msize;
672
673         msize = msg->size;
674
675         /* Put size in network byte order */
676         msg->size = htons(msg->size);
677
678         if (ip_vs_send_async(sock, (char *)msg, msize) != msize)
679                 IP_VS_ERR("ip_vs_send_async error\n");
680 }
681
682 static int
683 ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
684 {
685         struct msghdr           msg = {NULL,};
686         struct kvec             iov;
687         int                     len;
688
689         EnterFunction(7);
690
691         /* Receive a packet */
692         iov.iov_base     = buffer;
693         iov.iov_len      = (size_t)buflen;
694
695         len = kernel_recvmsg(sock, &msg, &iov, 1, buflen, 0);
696
697         if (len < 0)
698                 return -1;
699
700         LeaveFunction(7);
701         return len;
702 }
703
704
705 static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
706 static pid_t sync_master_pid = 0;
707 static pid_t sync_backup_pid = 0;
708
709 static DECLARE_WAIT_QUEUE_HEAD(stop_sync_wait);
710 static int stop_master_sync = 0;
711 static int stop_backup_sync = 0;
712
713 static void sync_master_loop(void)
714 {
715         struct socket *sock;
716         struct ip_vs_sync_buff *sb;
717
718         /* create the sending multicast socket */
719         sock = make_send_sock();
720         if (!sock)
721                 return;
722
723         IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
724                    "syncid = %d\n",
725                    ip_vs_master_mcast_ifn, ip_vs_master_syncid);
726
727         for (;;) {
728                 while ((sb=sb_dequeue())) {
729                         ip_vs_send_sync_msg(sock, sb->mesg);
730                         ip_vs_sync_buff_release(sb);
731                 }
732
733                 /* check if entries stay in curr_sb for 2 seconds */
734                 if ((sb = get_curr_sync_buff(2*HZ))) {
735                         ip_vs_send_sync_msg(sock, sb->mesg);
736                         ip_vs_sync_buff_release(sb);
737                 }
738
739                 if (stop_master_sync)
740                         break;
741
742                 msleep_interruptible(1000);
743         }
744
745         /* clean up the sync_buff queue */
746         while ((sb=sb_dequeue())) {
747                 ip_vs_sync_buff_release(sb);
748         }
749
750         /* clean up the current sync_buff */
751         if ((sb = get_curr_sync_buff(0))) {
752                 ip_vs_sync_buff_release(sb);
753         }
754
755         /* release the sending multicast socket */
756         sock_release(sock);
757 }
758
759
760 static void sync_backup_loop(void)
761 {
762         struct socket *sock;
763         char *buf;
764         int len;
765
766         if (!(buf = kmalloc(sync_recv_mesg_maxlen, GFP_ATOMIC))) {
767                 IP_VS_ERR("sync_backup_loop: kmalloc error\n");
768                 return;
769         }
770
771         /* create the receiving multicast socket */
772         sock = make_receive_sock();
773         if (!sock)
774                 goto out;
775
776         IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
777                    "syncid = %d\n",
778                    ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
779
780         for (;;) {
781                 /* do you have data now? */
782                 while (!skb_queue_empty(&(sock->sk->sk_receive_queue))) {
783                         if ((len =
784                              ip_vs_receive(sock, buf,
785                                            sync_recv_mesg_maxlen)) <= 0) {
786                                 IP_VS_ERR("receiving message error\n");
787                                 break;
788                         }
789                         /* disable bottom half, because it accessed the data
790                            shared by softirq while getting/creating conns */
791                         local_bh_disable();
792                         ip_vs_process_message(buf, len);
793                         local_bh_enable();
794                 }
795
796                 if (stop_backup_sync)
797                         break;
798
799                 msleep_interruptible(1000);
800         }
801
802         /* release the sending multicast socket */
803         sock_release(sock);
804
805   out:
806         kfree(buf);
807 }
808
809
810 static void set_sync_pid(int sync_state, pid_t sync_pid)
811 {
812         if (sync_state == IP_VS_STATE_MASTER)
813                 sync_master_pid = sync_pid;
814         else if (sync_state == IP_VS_STATE_BACKUP)
815                 sync_backup_pid = sync_pid;
816 }
817
818 static void set_stop_sync(int sync_state, int set)
819 {
820         if (sync_state == IP_VS_STATE_MASTER)
821                 stop_master_sync = set;
822         else if (sync_state == IP_VS_STATE_BACKUP)
823                 stop_backup_sync = set;
824         else {
825                 stop_master_sync = set;
826                 stop_backup_sync = set;
827         }
828 }
829
830 static int sync_thread(void *startup)
831 {
832         DECLARE_WAITQUEUE(wait, current);
833         mm_segment_t oldmm;
834         int state;
835         const char *name;
836         struct ip_vs_sync_thread_data *tinfo = startup;
837
838         /* increase the module use count */
839         ip_vs_use_count_inc();
840
841         if (ip_vs_sync_state & IP_VS_STATE_MASTER && !sync_master_pid) {
842                 state = IP_VS_STATE_MASTER;
843                 name = "ipvs_syncmaster";
844         } else if (ip_vs_sync_state & IP_VS_STATE_BACKUP && !sync_backup_pid) {
845                 state = IP_VS_STATE_BACKUP;
846                 name = "ipvs_syncbackup";
847         } else {
848                 IP_VS_BUG();
849                 ip_vs_use_count_dec();
850                 return -EINVAL;
851         }
852
853         daemonize(name);
854
855         oldmm = get_fs();
856         set_fs(KERNEL_DS);
857
858         /* Block all signals */
859         spin_lock_irq(&current->sighand->siglock);
860         siginitsetinv(&current->blocked, 0);
861         recalc_sigpending();
862         spin_unlock_irq(&current->sighand->siglock);
863
864         /* set the maximum length of sync message */
865         set_sync_mesg_maxlen(state);
866
867         /* set up multicast address */
868         mcast_addr.sin_family = AF_INET;
869         mcast_addr.sin_port = htons(IP_VS_SYNC_PORT);
870         mcast_addr.sin_addr.s_addr = htonl(IP_VS_SYNC_GROUP);
871
872         add_wait_queue(&sync_wait, &wait);
873
874         set_sync_pid(state, task_pid_nr(current));
875         complete(tinfo->startup);
876
877         /*
878          * once we call the completion queue above, we should
879          * null out that reference, since its allocated on the
880          * stack of the creating kernel thread
881          */
882         tinfo->startup = NULL;
883
884         /* processing master/backup loop here */
885         if (state == IP_VS_STATE_MASTER)
886                 sync_master_loop();
887         else if (state == IP_VS_STATE_BACKUP)
888                 sync_backup_loop();
889         else IP_VS_BUG();
890
891         remove_wait_queue(&sync_wait, &wait);
892
893         /* thread exits */
894
895         /*
896          * If we weren't explicitly stopped, then we
897          * exited in error, and should undo our state
898          */
899         if ((!stop_master_sync) && (!stop_backup_sync))
900                 ip_vs_sync_state -= tinfo->state;
901
902         set_sync_pid(state, 0);
903         IP_VS_INFO("sync thread stopped!\n");
904
905         set_fs(oldmm);
906
907         /* decrease the module use count */
908         ip_vs_use_count_dec();
909
910         set_stop_sync(state, 0);
911         wake_up(&stop_sync_wait);
912
913         /*
914          * we need to free the structure that was allocated
915          * for us in start_sync_thread
916          */
917         kfree(tinfo);
918         return 0;
919 }
920
921
922 static int fork_sync_thread(void *startup)
923 {
924         pid_t pid;
925
926         /* fork the sync thread here, then the parent process of the
927            sync thread is the init process after this thread exits. */
928   repeat:
929         if ((pid = kernel_thread(sync_thread, startup, 0)) < 0) {
930                 IP_VS_ERR("could not create sync_thread due to %d... "
931                           "retrying.\n", pid);
932                 msleep_interruptible(1000);
933                 goto repeat;
934         }
935
936         return 0;
937 }
938
939
940 int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
941 {
942         DECLARE_COMPLETION_ONSTACK(startup);
943         pid_t pid;
944         struct ip_vs_sync_thread_data *tinfo;
945
946         if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
947             (state == IP_VS_STATE_BACKUP && sync_backup_pid))
948                 return -EEXIST;
949
950         /*
951          * Note that tinfo will be freed in sync_thread on exit
952          */
953         tinfo = kmalloc(sizeof(struct ip_vs_sync_thread_data), GFP_KERNEL);
954         if (!tinfo)
955                 return -ENOMEM;
956
957         IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
958         IP_VS_DBG(7, "Each ip_vs_sync_conn entry need %Zd bytes\n",
959                   sizeof(struct ip_vs_sync_conn));
960
961         ip_vs_sync_state |= state;
962         if (state == IP_VS_STATE_MASTER) {
963                 strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
964                         sizeof(ip_vs_master_mcast_ifn));
965                 ip_vs_master_syncid = syncid;
966         } else {
967                 strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
968                         sizeof(ip_vs_backup_mcast_ifn));
969                 ip_vs_backup_syncid = syncid;
970         }
971
972         tinfo->state = state;
973         tinfo->startup = &startup;
974
975   repeat:
976         if ((pid = kernel_thread(fork_sync_thread, tinfo, 0)) < 0) {
977                 IP_VS_ERR("could not create fork_sync_thread due to %d... "
978                           "retrying.\n", pid);
979                 msleep_interruptible(1000);
980                 goto repeat;
981         }
982
983         wait_for_completion(&startup);
984
985         return 0;
986 }
987
988
989 int stop_sync_thread(int state)
990 {
991         DECLARE_WAITQUEUE(wait, current);
992
993         if ((state == IP_VS_STATE_MASTER && !sync_master_pid) ||
994             (state == IP_VS_STATE_BACKUP && !sync_backup_pid))
995                 return -ESRCH;
996
997         IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current));
998         IP_VS_INFO("stopping sync thread %d ...\n",
999                    (state == IP_VS_STATE_MASTER) ?
1000                    sync_master_pid : sync_backup_pid);
1001
1002         __set_current_state(TASK_UNINTERRUPTIBLE);
1003         add_wait_queue(&stop_sync_wait, &wait);
1004         set_stop_sync(state, 1);
1005         ip_vs_sync_state -= state;
1006         wake_up(&sync_wait);
1007         schedule();
1008         __set_current_state(TASK_RUNNING);
1009         remove_wait_queue(&stop_sync_wait, &wait);
1010
1011         /* Note: no need to reap the sync thread, because its parent
1012            process is the init process */
1013
1014         if ((state == IP_VS_STATE_MASTER && stop_master_sync) ||
1015             (state == IP_VS_STATE_BACKUP && stop_backup_sync))
1016                 IP_VS_BUG();
1017
1018         return 0;
1019 }