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[IPV6] NDISC: Fix setting base_reachable_time_ms variable.
[linux-2.6-block.git] / net / ipv4 / ipvs / ip_vs_sync.c
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1da177e4
LT		 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>
14c85021 24#include <linux/inetdevice.h>
1da177e4
LT		 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 */
14c85021 31#include <linux/udp.h>
1da177e4
LT		 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 */
46struct ip_vs_sync_conn {
47 __u8 reserved;
48
49 /* Protocol, addresses and port numbers */
50 __u8 protocol; /* Which protocol (TCP/UDP) */
014d730d
AV		 51 __be16 cport;
52 __be16 vport;
53 __be16 dport;
54 __be32 caddr; /* client address */
55 __be32 vaddr; /* virtual address */
56 __be32 daddr; /* destination address */
1da177e4
LT		 57
58 /* Flags and state transition */
014d730d
AV		 59 __be16 flags; /* status flags */
60 __be16 state; /* state info */
1da177e4
LT		 61
62 /* The sequence options start here */
63};
64
65struct 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
cc0191ae
NH		 70struct ip_vs_sync_thread_data {
71 struct completion *startup;
72 int state;
73};
74
1da177e4
LT		 75#define IP_VS_SYNC_CONN_TIMEOUT (3*60*HZ)
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
104struct ip_vs_sync_mesg {
105 __u8 nr_conns;
106 __u8 syncid;
107 __u16 size;
108
109 /* ip_vs_sync_conn entries start here */
110};
111
112/* the maximum length of sync (sending/receiving) message */
113static int sync_send_mesg_maxlen;
114static int sync_recv_mesg_maxlen;
115
116struct ip_vs_sync_buff {
117 struct list_head list;
118 unsigned long firstuse;
119
120 /* pointers for the message data */
121 struct ip_vs_sync_mesg *mesg;
122 unsigned char *head;
123 unsigned char *end;
124};
125
126
127/* the sync_buff list head and the lock */
128static LIST_HEAD(ip_vs_sync_queue);
129static DEFINE_SPINLOCK(ip_vs_sync_lock);
130
131/* current sync_buff for accepting new conn entries */
132static struct ip_vs_sync_buff *curr_sb = NULL;
133static DEFINE_SPINLOCK(curr_sb_lock);
134
135/* ipvs sync daemon state */
136volatile int ip_vs_sync_state = IP_VS_STATE_NONE;
137volatile int ip_vs_master_syncid = 0;
138volatile int ip_vs_backup_syncid = 0;
139
140/* multicast interface name */
141char ip_vs_master_mcast_ifn[IP_VS_IFNAME_MAXLEN];
142char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
143
144/* multicast addr */
145static struct sockaddr_in mcast_addr;
146
147
148static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
149{
150 spin_lock(&ip_vs_sync_lock);
151 list_add_tail(&sb->list, &ip_vs_sync_queue);
152 spin_unlock(&ip_vs_sync_lock);
153}
154
155static inline struct ip_vs_sync_buff * sb_dequeue(void)
156{
157 struct ip_vs_sync_buff *sb;
158
159 spin_lock_bh(&ip_vs_sync_lock);
160 if (list_empty(&ip_vs_sync_queue)) {
161 sb = NULL;
162 } else {
163 sb = list_entry(ip_vs_sync_queue.next,
164 struct ip_vs_sync_buff,
165 list);
166 list_del(&sb->list);
167 }
168 spin_unlock_bh(&ip_vs_sync_lock);
169
170 return sb;
171}
172
173static inline struct ip_vs_sync_buff * ip_vs_sync_buff_create(void)
174{
175 struct ip_vs_sync_buff *sb;
176
177 if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
178 return NULL;
179
180 if (!(sb->mesg=kmalloc(sync_send_mesg_maxlen, GFP_ATOMIC))) {
181 kfree(sb);
182 return NULL;
183 }
184 sb->mesg->nr_conns = 0;
185 sb->mesg->syncid = ip_vs_master_syncid;
186 sb->mesg->size = 4;
187 sb->head = (unsigned char *)sb->mesg + 4;
188 sb->end = (unsigned char *)sb->mesg + sync_send_mesg_maxlen;
189 sb->firstuse = jiffies;
190 return sb;
191}
192
193static inline void ip_vs_sync_buff_release(struct ip_vs_sync_buff *sb)
194{
195 kfree(sb->mesg);
196 kfree(sb);
197}
198
199/*
200 * Get the current sync buffer if it has been created for more
201 * than the specified time or the specified time is zero.
202 */
203static inline struct ip_vs_sync_buff *
204get_curr_sync_buff(unsigned long time)
205{
206 struct ip_vs_sync_buff *sb;
207
208 spin_lock_bh(&curr_sb_lock);
209 if (curr_sb && (time == 0 ||
210 time_before(jiffies - curr_sb->firstuse, time))) {
211 sb = curr_sb;
212 curr_sb = NULL;
213 } else
214 sb = NULL;
215 spin_unlock_bh(&curr_sb_lock);
216 return sb;
217}
218
219
220/*
221 * Add an ip_vs_conn information into the current sync_buff.
222 * Called by ip_vs_in.
223 */
224void ip_vs_sync_conn(struct ip_vs_conn *cp)
225{
226 struct ip_vs_sync_mesg *m;
227 struct ip_vs_sync_conn *s;
228 int len;
229
230 spin_lock(&curr_sb_lock);
231 if (!curr_sb) {
232 if (!(curr_sb=ip_vs_sync_buff_create())) {
233 spin_unlock(&curr_sb_lock);
234 IP_VS_ERR("ip_vs_sync_buff_create failed.\n");
235 return;
236 }
237 }
238
239 len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
240 SIMPLE_CONN_SIZE;
241 m = curr_sb->mesg;
242 s = (struct ip_vs_sync_conn *)curr_sb->head;
243
244 /* copy members */
245 s->protocol = cp->protocol;
246 s->cport = cp->cport;
247 s->vport = cp->vport;
248 s->dport = cp->dport;
249 s->caddr = cp->caddr;
250 s->vaddr = cp->vaddr;
251 s->daddr = cp->daddr;
252 s->flags = htons(cp->flags & ~IP_VS_CONN_F_HASHED);
253 s->state = htons(cp->state);
254 if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
255 struct ip_vs_sync_conn_options *opt =
256 (struct ip_vs_sync_conn_options *)&s[1];
257 memcpy(opt, &cp->in_seq, sizeof(*opt));
258 }
259
260 m->nr_conns++;
261 m->size += len;
262 curr_sb->head += len;
263
264 /* check if there is a space for next one */
265 if (curr_sb->head+FULL_CONN_SIZE > curr_sb->end) {
266 sb_queue_tail(curr_sb);
267 curr_sb = NULL;
268 }
269 spin_unlock(&curr_sb_lock);
270
271 /* synchronize its controller if it has */
272 if (cp->control)
273 ip_vs_sync_conn(cp->control);
274}
275
276
277/*
278 * Process received multicast message and create the corresponding
279 * ip_vs_conn entries.
280 */
281static void ip_vs_process_message(const char *buffer, const size_t buflen)
282{
283 struct ip_vs_sync_mesg *m = (struct ip_vs_sync_mesg *)buffer;
284 struct ip_vs_sync_conn *s;
285 struct ip_vs_sync_conn_options *opt;
286 struct ip_vs_conn *cp;
287 char *p;
288 int i;
289
290 /* Convert size back to host byte order */
291 m->size = ntohs(m->size);
292
293 if (buflen != m->size) {
294 IP_VS_ERR("bogus message\n");
295 return;
296 }
297
298 /* SyncID sanity check */
299 if (ip_vs_backup_syncid != 0 && m->syncid != ip_vs_backup_syncid) {
300 IP_VS_DBG(7, "Ignoring incoming msg with syncid = %d\n",
301 m->syncid);
302 return;
303 }
304
305 p = (char *)buffer + sizeof(struct ip_vs_sync_mesg);
306 for (i=0; i<m->nr_conns; i++) {
87375ab4
JA		 307 unsigned flags;
308
1da177e4 309 s = (struct ip_vs_sync_conn *)p;
87375ab4
JA		 310 flags = ntohs(s->flags);
311 if (!(flags & IP_VS_CONN_F_TEMPLATE))
312 cp = ip_vs_conn_in_get(s->protocol,
313 s->caddr, s->cport,
314 s->vaddr, s->vport);
315 else
316 cp = ip_vs_ct_in_get(s->protocol,
317 s->caddr, s->cport,
318 s->vaddr, s->vport);
1da177e4
LT		 319 if (!cp) {
320 cp = ip_vs_conn_new(s->protocol,
321 s->caddr, s->cport,
322 s->vaddr, s->vport,
323 s->daddr, s->dport,
87375ab4 324 flags, NULL);
1da177e4
LT		 325 if (!cp) {
326 IP_VS_ERR("ip_vs_conn_new failed\n");
327 return;
328 }
329 cp->state = ntohs(s->state);
330 } else if (!cp->dest) {
331 /* it is an entry created by the synchronization */
332 cp->state = ntohs(s->state);
87375ab4 333 cp->flags = flags | IP_VS_CONN_F_HASHED;
1da177e4
LT		 334 } /* Note that we don't touch its state and flags
335 if it is a normal entry. */
336
87375ab4 337 if (flags & IP_VS_CONN_F_SEQ_MASK) {
1da177e4
LT		 338 opt = (struct ip_vs_sync_conn_options *)&s[1];
339 memcpy(&cp->in_seq, opt, sizeof(*opt));
340 p += FULL_CONN_SIZE;
341 } else
342 p += SIMPLE_CONN_SIZE;
343
344 atomic_set(&cp->in_pkts, sysctl_ip_vs_sync_threshold[0]);
345 cp->timeout = IP_VS_SYNC_CONN_TIMEOUT;
346 ip_vs_conn_put(cp);
347
348 if (p > buffer+buflen) {
349 IP_VS_ERR("bogus message\n");
350 return;
351 }
352 }
353}
354
355
356/*
357 * Setup loopback of outgoing multicasts on a sending socket
358 */
359static void set_mcast_loop(struct sock *sk, u_char loop)
360{
361 struct inet_sock *inet = inet_sk(sk);
362
363 /* setsockopt(sock, SOL_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); */
364 lock_sock(sk);
365 inet->mc_loop = loop ? 1 : 0;
366 release_sock(sk);
367}
368
369/*
370 * Specify TTL for outgoing multicasts on a sending socket
371 */
372static void set_mcast_ttl(struct sock *sk, u_char ttl)
373{
374 struct inet_sock *inet = inet_sk(sk);
375
376 /* setsockopt(sock, SOL_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); */
377 lock_sock(sk);
378 inet->mc_ttl = ttl;
379 release_sock(sk);
380}
381
382/*
383 * Specifiy default interface for outgoing multicasts
384 */
385static int set_mcast_if(struct sock *sk, char *ifname)
386{
387 struct net_device *dev;
388 struct inet_sock *inet = inet_sk(sk);
389
881d966b 390 if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
1da177e4
LT		 391 return -ENODEV;
392
393 if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
394 return -EINVAL;
395
396 lock_sock(sk);
397 inet->mc_index = dev->ifindex;
398 /* inet->mc_addr = 0; */
399 release_sock(sk);
400
401 return 0;
402}
403
404
405/*
406 * Set the maximum length of sync message according to the
407 * specified interface's MTU.
408 */
409static int set_sync_mesg_maxlen(int sync_state)
410{
411 struct net_device *dev;
412 int num;
413
414 if (sync_state == IP_VS_STATE_MASTER) {
881d966b 415 if ((dev = __dev_get_by_name(&init_net, ip_vs_master_mcast_ifn)) == NULL)
1da177e4
LT		 416 return -ENODEV;
417
418 num = (dev->mtu - sizeof(struct iphdr) -
419 sizeof(struct udphdr) -
420 SYNC_MESG_HEADER_LEN - 20) / SIMPLE_CONN_SIZE;
421 sync_send_mesg_maxlen =
422 SYNC_MESG_HEADER_LEN + SIMPLE_CONN_SIZE * num;
423 IP_VS_DBG(7, "setting the maximum length of sync sending "
424 "message %d.\n", sync_send_mesg_maxlen);
425 } else if (sync_state == IP_VS_STATE_BACKUP) {
881d966b 426 if ((dev = __dev_get_by_name(&init_net, ip_vs_backup_mcast_ifn)) == NULL)
1da177e4
LT		 427 return -ENODEV;
428
429 sync_recv_mesg_maxlen = dev->mtu -
430 sizeof(struct iphdr) - sizeof(struct udphdr);
431 IP_VS_DBG(7, "setting the maximum length of sync receiving "
432 "message %d.\n", sync_recv_mesg_maxlen);
433 }
434
435 return 0;
436}
437
438
439/*
440 * Join a multicast group.
441 * the group is specified by a class D multicast address 224.0.0.0/8
442 * in the in_addr structure passed in as a parameter.
443 */
444static int
445join_mcast_group(struct sock *sk, struct in_addr *addr, char *ifname)
446{
447 struct ip_mreqn mreq;
448 struct net_device *dev;
449 int ret;
450
451 memset(&mreq, 0, sizeof(mreq));
452 memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));
453
881d966b 454 if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
1da177e4
LT		 455 return -ENODEV;
456 if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
457 return -EINVAL;
458
459 mreq.imr_ifindex = dev->ifindex;
460
461 lock_sock(sk);
462 ret = ip_mc_join_group(sk, &mreq);
463 release_sock(sk);
464
465 return ret;
466}
467
468
469static int bind_mcastif_addr(struct socket *sock, char *ifname)
470{
471 struct net_device *dev;
a61ced5d 472 __be32 addr;
1da177e4
LT		 473 struct sockaddr_in sin;
474
881d966b 475 if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
1da177e4
LT		 476 return -ENODEV;
477
478 addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
479 if (!addr)
480 IP_VS_ERR("You probably need to specify IP address on "
481 "multicast interface.\n");
482
483 IP_VS_DBG(7, "binding socket with (%s) %u.%u.%u.%u\n",
484 ifname, NIPQUAD(addr));
485
486 /* Now bind the socket with the address of multicast interface */
487 sin.sin_family = AF_INET;
488 sin.sin_addr.s_addr = addr;
489 sin.sin_port = 0;
490
491 return sock->ops->bind(sock, (struct sockaddr*)&sin, sizeof(sin));
492}
493
494/*
495 * Set up sending multicast socket over UDP
496 */
497static struct socket * make_send_sock(void)
498{
499 struct socket *sock;
500
501 /* First create a socket */
502 if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
503 IP_VS_ERR("Error during creation of socket; terminating\n");
504 return NULL;
505 }
506
507 if (set_mcast_if(sock->sk, ip_vs_master_mcast_ifn) < 0) {
508 IP_VS_ERR("Error setting outbound mcast interface\n");
509 goto error;
510 }
511
512 set_mcast_loop(sock->sk, 0);
513 set_mcast_ttl(sock->sk, 1);
514
515 if (bind_mcastif_addr(sock, ip_vs_master_mcast_ifn) < 0) {
516 IP_VS_ERR("Error binding address of the mcast interface\n");
517 goto error;
518 }
519
520 if (sock->ops->connect(sock,
521 (struct sockaddr*)&mcast_addr,
522 sizeof(struct sockaddr), 0) < 0) {
523 IP_VS_ERR("Error connecting to the multicast addr\n");
524 goto error;
525 }
526
527 return sock;
528
529 error:
530 sock_release(sock);
531 return NULL;
532}
533
534
535/*
536 * Set up receiving multicast socket over UDP
537 */
538static struct socket * make_receive_sock(void)
539{
540 struct socket *sock;
541
542 /* First create a socket */
543 if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
544 IP_VS_ERR("Error during creation of socket; terminating\n");
545 return NULL;
546 }
547
548 /* it is equivalent to the REUSEADDR option in user-space */
549 sock->sk->sk_reuse = 1;
550
551 if (sock->ops->bind(sock,
552 (struct sockaddr*)&mcast_addr,
553 sizeof(struct sockaddr)) < 0) {
554 IP_VS_ERR("Error binding to the multicast addr\n");
555 goto error;
556 }
557
558 /* join the multicast group */
559 if (join_mcast_group(sock->sk,
560 (struct in_addr*)&mcast_addr.sin_addr,
561 ip_vs_backup_mcast_ifn) < 0) {
562 IP_VS_ERR("Error joining to the multicast group\n");
563 goto error;
564 }
565
566 return sock;
567
568 error:
569 sock_release(sock);
570 return NULL;
571}
572
573
574static int
575ip_vs_send_async(struct socket *sock, const char *buffer, const size_t length)
576{
577 struct msghdr msg = {.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL};
578 struct kvec iov;
579 int len;
580
581 EnterFunction(7);
582 iov.iov_base = (void *)buffer;
583 iov.iov_len = length;
584
585 len = kernel_sendmsg(sock, &msg, &iov, 1, (size_t)(length));
586
587 LeaveFunction(7);
588 return len;
589}
590
591static void
592ip_vs_send_sync_msg(struct socket *sock, struct ip_vs_sync_mesg *msg)
593{
594 int msize;
595
596 msize = msg->size;
597
598 /* Put size in network byte order */
599 msg->size = htons(msg->size);
600
601 if (ip_vs_send_async(sock, (char *)msg, msize) != msize)
602 IP_VS_ERR("ip_vs_send_async error\n");
603}
604
605static int
606ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
607{
608 struct msghdr msg = {NULL,};
609 struct kvec iov;
610 int len;
611
612 EnterFunction(7);
613
614 /* Receive a packet */
615 iov.iov_base = buffer;
616 iov.iov_len = (size_t)buflen;
617
618 len = kernel_recvmsg(sock, &msg, &iov, 1, buflen, 0);
619
620 if (len < 0)
621 return -1;
622
623 LeaveFunction(7);
624 return len;
625}
626
627
628static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
629static pid_t sync_master_pid = 0;
630static pid_t sync_backup_pid = 0;
631
632static DECLARE_WAIT_QUEUE_HEAD(stop_sync_wait);
633static int stop_master_sync = 0;
634static int stop_backup_sync = 0;
635
636static void sync_master_loop(void)
637{
638 struct socket *sock;
639 struct ip_vs_sync_buff *sb;
640
641 /* create the sending multicast socket */
642 sock = make_send_sock();
643 if (!sock)
644 return;
645
646 IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
647 "syncid = %d\n",
648 ip_vs_master_mcast_ifn, ip_vs_master_syncid);
649
650 for (;;) {
651 while ((sb=sb_dequeue())) {
652 ip_vs_send_sync_msg(sock, sb->mesg);
653 ip_vs_sync_buff_release(sb);
654 }
655
656 /* check if entries stay in curr_sb for 2 seconds */
657 if ((sb = get_curr_sync_buff(2*HZ))) {
658 ip_vs_send_sync_msg(sock, sb->mesg);
659 ip_vs_sync_buff_release(sb);
660 }
661
662 if (stop_master_sync)
663 break;
664
89eaeb09 665 msleep_interruptible(1000);
1da177e4
LT		 666 }
667
668 /* clean up the sync_buff queue */
669 while ((sb=sb_dequeue())) {
670 ip_vs_sync_buff_release(sb);
671 }
672
673 /* clean up the current sync_buff */
674 if ((sb = get_curr_sync_buff(0))) {
675 ip_vs_sync_buff_release(sb);
676 }
677
678 /* release the sending multicast socket */
679 sock_release(sock);
680}
681
682
683static void sync_backup_loop(void)
684{
685 struct socket *sock;
686 char *buf;
687 int len;
688
689 if (!(buf = kmalloc(sync_recv_mesg_maxlen, GFP_ATOMIC))) {
690 IP_VS_ERR("sync_backup_loop: kmalloc error\n");
691 return;
692 }
693
694 /* create the receiving multicast socket */
695 sock = make_receive_sock();
696 if (!sock)
697 goto out;
698
699 IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
700 "syncid = %d\n",
701 ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
702
703 for (;;) {
704 /* do you have data now? */
705 while (!skb_queue_empty(&(sock->sk->sk_receive_queue))) {
706 if ((len =
707 ip_vs_receive(sock, buf,
708 sync_recv_mesg_maxlen)) <= 0) {
709 IP_VS_ERR("receiving message error\n");
710 break;
711 }
712 /* disable bottom half, because it accessed the data
713 shared by softirq while getting/creating conns */
714 local_bh_disable();
715 ip_vs_process_message(buf, len);
716 local_bh_enable();
717 }
718
719 if (stop_backup_sync)
720 break;
721
89eaeb09 722 msleep_interruptible(1000);
1da177e4
LT		 723 }
724
725 /* release the sending multicast socket */
726 sock_release(sock);
727
728 out:
729 kfree(buf);
730}
731
732
733static void set_sync_pid(int sync_state, pid_t sync_pid)
734{
735 if (sync_state == IP_VS_STATE_MASTER)
736 sync_master_pid = sync_pid;
737 else if (sync_state == IP_VS_STATE_BACKUP)
738 sync_backup_pid = sync_pid;
739}
740
741static void set_stop_sync(int sync_state, int set)
742{
743 if (sync_state == IP_VS_STATE_MASTER)
744 stop_master_sync = set;
745 else if (sync_state == IP_VS_STATE_BACKUP)
746 stop_backup_sync = set;
747 else {
748 stop_master_sync = set;
749 stop_backup_sync = set;
750 }
751}
752
753static int sync_thread(void *startup)
754{
755 DECLARE_WAITQUEUE(wait, current);
756 mm_segment_t oldmm;
757 int state;
758 const char *name;
cc0191ae 759 struct ip_vs_sync_thread_data *tinfo = startup;
1da177e4
LT		 760
761 /* increase the module use count */
762 ip_vs_use_count_inc();
763
764 if (ip_vs_sync_state & IP_VS_STATE_MASTER && !sync_master_pid) {
765 state = IP_VS_STATE_MASTER;
766 name = "ipvs_syncmaster";
767 } else if (ip_vs_sync_state & IP_VS_STATE_BACKUP && !sync_backup_pid) {
768 state = IP_VS_STATE_BACKUP;
769 name = "ipvs_syncbackup";
770 } else {
771 IP_VS_BUG();
772 ip_vs_use_count_dec();
773 return -EINVAL;
774 }
775
776 daemonize(name);
777
778 oldmm = get_fs();
779 set_fs(KERNEL_DS);
780
781 /* Block all signals */
782 spin_lock_irq(&current->sighand->siglock);
783 siginitsetinv(&current->blocked, 0);
784 recalc_sigpending();
785 spin_unlock_irq(&current->sighand->siglock);
786
787 /* set the maximum length of sync message */
788 set_sync_mesg_maxlen(state);
789
790 /* set up multicast address */
791 mcast_addr.sin_family = AF_INET;
792 mcast_addr.sin_port = htons(IP_VS_SYNC_PORT);
793 mcast_addr.sin_addr.s_addr = htonl(IP_VS_SYNC_GROUP);
794
795 add_wait_queue(&sync_wait, &wait);
796
6651fd56 797 set_sync_pid(state, task_pid_nr(current));
cc0191ae
NH		 798 complete(tinfo->startup);
799
800 /*
801 * once we call the completion queue above, we should
802 * null out that reference, since its allocated on the
803 * stack of the creating kernel thread
804 */
805 tinfo->startup = NULL;
1da177e4
LT		 806
807 /* processing master/backup loop here */
808 if (state == IP_VS_STATE_MASTER)
809 sync_master_loop();
810 else if (state == IP_VS_STATE_BACKUP)
811 sync_backup_loop();
812 else IP_VS_BUG();
813
814 remove_wait_queue(&sync_wait, &wait);
815
816 /* thread exits */
cc0191ae
NH		 817
818 /*
819 * If we weren't explicitly stopped, then we
820 * exited in error, and should undo our state
821 */
822 if ((!stop_master_sync) && (!stop_backup_sync))
823 ip_vs_sync_state -= tinfo->state;
824
1da177e4
LT		 825 set_sync_pid(state, 0);
826 IP_VS_INFO("sync thread stopped!\n");
827
828 set_fs(oldmm);
829
830 /* decrease the module use count */
831 ip_vs_use_count_dec();
832
833 set_stop_sync(state, 0);
834 wake_up(&stop_sync_wait);
835
cc0191ae
NH		 836 /*
837 * we need to free the structure that was allocated
838 * for us in start_sync_thread
839 */
840 kfree(tinfo);
1da177e4
LT		 841 return 0;
842}
843
844
845static int fork_sync_thread(void *startup)
846{
847 pid_t pid;
848
849 /* fork the sync thread here, then the parent process of the
850 sync thread is the init process after this thread exits. */
851 repeat:
852 if ((pid = kernel_thread(sync_thread, startup, 0)) < 0) {
853 IP_VS_ERR("could not create sync_thread due to %d... "
854 "retrying.\n", pid);
89eaeb09 855 msleep_interruptible(1000);
1da177e4
LT		 856 goto repeat;
857 }
858
859 return 0;
860}
861
862
863int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
864{
6e9a4738 865 DECLARE_COMPLETION_ONSTACK(startup);
1da177e4 866 pid_t pid;
cc0191ae 867 struct ip_vs_sync_thread_data *tinfo;
1da177e4
LT		 868
869 if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
870 (state == IP_VS_STATE_BACKUP && sync_backup_pid))
871 return -EEXIST;
872
cc0191ae
NH		 873 /*
874 * Note that tinfo will be freed in sync_thread on exit
875 */
876 tinfo = kmalloc(sizeof(struct ip_vs_sync_thread_data), GFP_KERNEL);
877 if (!tinfo)
878 return -ENOMEM;
879
ba25f9dc 880 IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, task_pid_nr(current));
1da177e4
LT		 881 IP_VS_DBG(7, "Each ip_vs_sync_conn entry need %Zd bytes\n",
882 sizeof(struct ip_vs_sync_conn));
883
884 ip_vs_sync_state |= state;
885 if (state == IP_VS_STATE_MASTER) {
37004af3
SH		 886 strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
887 sizeof(ip_vs_master_mcast_ifn));
1da177e4
LT		 888 ip_vs_master_syncid = syncid;
889 } else {
37004af3
SH		 890 strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
891 sizeof(ip_vs_backup_mcast_ifn));
1da177e4
LT		 892 ip_vs_backup_syncid = syncid;
893 }
894
cc0191ae
NH		 895 tinfo->state = state;
896 tinfo->startup = &startup;
897
1da177e4 898 repeat:
cc0191ae 899 if ((pid = kernel_thread(fork_sync_thread, tinfo, 0)) < 0) {
1da177e4
LT		 900 IP_VS_ERR("could not create fork_sync_thread due to %d... "
901 "retrying.\n", pid);
89eaeb09 902 msleep_interruptible(1000);
1da177e4
LT		 903 goto repeat;
904 }
905
906 wait_for_completion(&startup);
907
908 return 0;
909}
910
911
912int stop_sync_thread(int state)
913{
914 DECLARE_WAITQUEUE(wait, current);
915
916 if ((state == IP_VS_STATE_MASTER && !sync_master_pid) ||
917 (state == IP_VS_STATE_BACKUP && !sync_backup_pid))
918 return -ESRCH;
919
ba25f9dc 920 IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, task_pid_nr(current));
1da177e4 921 IP_VS_INFO("stopping sync thread %d ...\n",
37004af3
SH		 922 (state == IP_VS_STATE_MASTER) ?
923 sync_master_pid : sync_backup_pid);
1da177e4
LT		 924
925 __set_current_state(TASK_UNINTERRUPTIBLE);
926 add_wait_queue(&stop_sync_wait, &wait);
927 set_stop_sync(state, 1);
928 ip_vs_sync_state -= state;
929 wake_up(&sync_wait);
930 schedule();
931 __set_current_state(TASK_RUNNING);
932 remove_wait_queue(&stop_sync_wait, &wait);
933
934 /* Note: no need to reap the sync thread, because its parent
935 process is the init process */
936
937 if ((state == IP_VS_STATE_MASTER && stop_master_sync) ||
938 (state == IP_VS_STATE_BACKUP && stop_backup_sync))
939 IP_VS_BUG();
940
941 return 0;
942}
Linux 6.x block layer and io_uring tree(s)