0c043b6ce65e1b3148b249d4560f2e0174798b65
[linux-2.6.git] / net / netfilter / ipvs / ip_vs_core.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  *              Peter Kese <peter.kese@ijs.si>
10  *              Julian Anastasov <ja@ssi.bg>
11  *
12  *              This program is free software; you can redistribute it and/or
13  *              modify it under the terms of the GNU General Public License
14  *              as published by the Free Software Foundation; either version
15  *              2 of the License, or (at your option) any later version.
16  *
17  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
18  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
19  * and others.
20  *
21  * Changes:
22  *      Paul `Rusty' Russell            properly handle non-linear skbs
23  *      Harald Welte                    don't use nfcache
24  *
25  */
26
27 #define KMSG_COMPONENT "IPVS"
28 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
29
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/ip.h>
33 #include <linux/tcp.h>
34 #include <linux/sctp.h>
35 #include <linux/icmp.h>
36 #include <linux/slab.h>
37
38 #include <net/ip.h>
39 #include <net/tcp.h>
40 #include <net/udp.h>
41 #include <net/icmp.h>                   /* for icmp_send */
42 #include <net/route.h>
43 #include <net/ip6_checksum.h>
44
45 #include <linux/netfilter.h>
46 #include <linux/netfilter_ipv4.h>
47
48 #ifdef CONFIG_IP_VS_IPV6
49 #include <net/ipv6.h>
50 #include <linux/netfilter_ipv6.h>
51 #endif
52
53 #include <net/ip_vs.h>
54
55
56 EXPORT_SYMBOL(register_ip_vs_scheduler);
57 EXPORT_SYMBOL(unregister_ip_vs_scheduler);
58 EXPORT_SYMBOL(ip_vs_proto_name);
59 EXPORT_SYMBOL(ip_vs_conn_new);
60 EXPORT_SYMBOL(ip_vs_conn_in_get);
61 EXPORT_SYMBOL(ip_vs_conn_out_get);
62 #ifdef CONFIG_IP_VS_PROTO_TCP
63 EXPORT_SYMBOL(ip_vs_tcp_conn_listen);
64 #endif
65 EXPORT_SYMBOL(ip_vs_conn_put);
66 #ifdef CONFIG_IP_VS_DEBUG
67 EXPORT_SYMBOL(ip_vs_get_debug_level);
68 #endif
69
70
71 /* ID used in ICMP lookups */
72 #define icmp_id(icmph)          (((icmph)->un).echo.id)
73 #define icmpv6_id(icmph)        (icmph->icmp6_dataun.u_echo.identifier)
74
75 const char *ip_vs_proto_name(unsigned proto)
76 {
77         static char buf[20];
78
79         switch (proto) {
80         case IPPROTO_IP:
81                 return "IP";
82         case IPPROTO_UDP:
83                 return "UDP";
84         case IPPROTO_TCP:
85                 return "TCP";
86         case IPPROTO_SCTP:
87                 return "SCTP";
88         case IPPROTO_ICMP:
89                 return "ICMP";
90 #ifdef CONFIG_IP_VS_IPV6
91         case IPPROTO_ICMPV6:
92                 return "ICMPv6";
93 #endif
94         default:
95                 sprintf(buf, "IP_%d", proto);
96                 return buf;
97         }
98 }
99
100 void ip_vs_init_hash_table(struct list_head *table, int rows)
101 {
102         while (--rows >= 0)
103                 INIT_LIST_HEAD(&table[rows]);
104 }
105
106 static inline void
107 ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
108 {
109         struct ip_vs_dest *dest = cp->dest;
110         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
111                 spin_lock(&dest->stats.lock);
112                 dest->stats.ustats.inpkts++;
113                 dest->stats.ustats.inbytes += skb->len;
114                 spin_unlock(&dest->stats.lock);
115
116                 spin_lock(&dest->svc->stats.lock);
117                 dest->svc->stats.ustats.inpkts++;
118                 dest->svc->stats.ustats.inbytes += skb->len;
119                 spin_unlock(&dest->svc->stats.lock);
120
121                 spin_lock(&ip_vs_stats.lock);
122                 ip_vs_stats.ustats.inpkts++;
123                 ip_vs_stats.ustats.inbytes += skb->len;
124                 spin_unlock(&ip_vs_stats.lock);
125         }
126 }
127
128
129 static inline void
130 ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
131 {
132         struct ip_vs_dest *dest = cp->dest;
133         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
134                 spin_lock(&dest->stats.lock);
135                 dest->stats.ustats.outpkts++;
136                 dest->stats.ustats.outbytes += skb->len;
137                 spin_unlock(&dest->stats.lock);
138
139                 spin_lock(&dest->svc->stats.lock);
140                 dest->svc->stats.ustats.outpkts++;
141                 dest->svc->stats.ustats.outbytes += skb->len;
142                 spin_unlock(&dest->svc->stats.lock);
143
144                 spin_lock(&ip_vs_stats.lock);
145                 ip_vs_stats.ustats.outpkts++;
146                 ip_vs_stats.ustats.outbytes += skb->len;
147                 spin_unlock(&ip_vs_stats.lock);
148         }
149 }
150
151
152 static inline void
153 ip_vs_conn_stats(struct ip_vs_conn *cp, struct ip_vs_service *svc)
154 {
155         spin_lock(&cp->dest->stats.lock);
156         cp->dest->stats.ustats.conns++;
157         spin_unlock(&cp->dest->stats.lock);
158
159         spin_lock(&svc->stats.lock);
160         svc->stats.ustats.conns++;
161         spin_unlock(&svc->stats.lock);
162
163         spin_lock(&ip_vs_stats.lock);
164         ip_vs_stats.ustats.conns++;
165         spin_unlock(&ip_vs_stats.lock);
166 }
167
168
169 static inline int
170 ip_vs_set_state(struct ip_vs_conn *cp, int direction,
171                 const struct sk_buff *skb,
172                 struct ip_vs_protocol *pp)
173 {
174         if (unlikely(!pp->state_transition))
175                 return 0;
176         return pp->state_transition(cp, direction, skb, pp);
177 }
178
179
180 /*
181  *  IPVS persistent scheduling function
182  *  It creates a connection entry according to its template if exists,
183  *  or selects a server and creates a connection entry plus a template.
184  *  Locking: we are svc user (svc->refcnt), so we hold all dests too
185  *  Protocols supported: TCP, UDP
186  */
187 static struct ip_vs_conn *
188 ip_vs_sched_persist(struct ip_vs_service *svc,
189                     const struct sk_buff *skb,
190                     __be16 ports[2])
191 {
192         struct ip_vs_conn *cp = NULL;
193         struct ip_vs_iphdr iph;
194         struct ip_vs_dest *dest;
195         struct ip_vs_conn *ct;
196         __be16  dport;                  /* destination port to forward */
197         __be16  flags;
198         union nf_inet_addr snet;        /* source network of the client,
199                                            after masking */
200
201         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
202
203         /* Mask saddr with the netmask to adjust template granularity */
204 #ifdef CONFIG_IP_VS_IPV6
205         if (svc->af == AF_INET6)
206                 ipv6_addr_prefix(&snet.in6, &iph.saddr.in6, svc->netmask);
207         else
208 #endif
209                 snet.ip = iph.saddr.ip & svc->netmask;
210
211         IP_VS_DBG_BUF(6, "p-schedule: src %s:%u dest %s:%u "
212                       "mnet %s\n",
213                       IP_VS_DBG_ADDR(svc->af, &iph.saddr), ntohs(ports[0]),
214                       IP_VS_DBG_ADDR(svc->af, &iph.daddr), ntohs(ports[1]),
215                       IP_VS_DBG_ADDR(svc->af, &snet));
216
217         /*
218          * As far as we know, FTP is a very complicated network protocol, and
219          * it uses control connection and data connections. For active FTP,
220          * FTP server initialize data connection to the client, its source port
221          * is often 20. For passive FTP, FTP server tells the clients the port
222          * that it passively listens to,  and the client issues the data
223          * connection. In the tunneling or direct routing mode, the load
224          * balancer is on the client-to-server half of connection, the port
225          * number is unknown to the load balancer. So, a conn template like
226          * <caddr, 0, vaddr, 0, daddr, 0> is created for persistent FTP
227          * service, and a template like <caddr, 0, vaddr, vport, daddr, dport>
228          * is created for other persistent services.
229          */
230         if (ports[1] == svc->port) {
231                 /* Check if a template already exists */
232                 if (svc->port != FTPPORT)
233                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
234                                              &iph.daddr, ports[1]);
235                 else
236                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
237                                              &iph.daddr, 0);
238
239                 if (!ct || !ip_vs_check_template(ct)) {
240                         /*
241                          * No template found or the dest of the connection
242                          * template is not available.
243                          */
244                         dest = svc->scheduler->schedule(svc, skb);
245                         if (dest == NULL) {
246                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
247                                 return NULL;
248                         }
249
250                         /*
251                          * Create a template like <protocol,caddr,0,
252                          * vaddr,vport,daddr,dport> for non-ftp service,
253                          * and <protocol,caddr,0,vaddr,0,daddr,0>
254                          * for ftp service.
255                          */
256                         if (svc->port != FTPPORT)
257                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
258                                                     &snet, 0,
259                                                     &iph.daddr,
260                                                     ports[1],
261                                                     &dest->addr, dest->port,
262                                                     IP_VS_CONN_F_TEMPLATE,
263                                                     dest);
264                         else
265                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
266                                                     &snet, 0,
267                                                     &iph.daddr, 0,
268                                                     &dest->addr, 0,
269                                                     IP_VS_CONN_F_TEMPLATE,
270                                                     dest);
271                         if (ct == NULL)
272                                 return NULL;
273
274                         ct->timeout = svc->timeout;
275                 } else {
276                         /* set destination with the found template */
277                         dest = ct->dest;
278                 }
279                 dport = dest->port;
280         } else {
281                 /*
282                  * Note: persistent fwmark-based services and persistent
283                  * port zero service are handled here.
284                  * fwmark template: <IPPROTO_IP,caddr,0,fwmark,0,daddr,0>
285                  * port zero template: <protocol,caddr,0,vaddr,0,daddr,0>
286                  */
287                 if (svc->fwmark) {
288                         union nf_inet_addr fwmark = {
289                                 .ip = htonl(svc->fwmark)
290                         };
291
292                         ct = ip_vs_ct_in_get(svc->af, IPPROTO_IP, &snet, 0,
293                                              &fwmark, 0);
294                 } else
295                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
296                                              &iph.daddr, 0);
297
298                 if (!ct || !ip_vs_check_template(ct)) {
299                         /*
300                          * If it is not persistent port zero, return NULL,
301                          * otherwise create a connection template.
302                          */
303                         if (svc->port)
304                                 return NULL;
305
306                         dest = svc->scheduler->schedule(svc, skb);
307                         if (dest == NULL) {
308                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
309                                 return NULL;
310                         }
311
312                         /*
313                          * Create a template according to the service
314                          */
315                         if (svc->fwmark) {
316                                 union nf_inet_addr fwmark = {
317                                         .ip = htonl(svc->fwmark)
318                                 };
319
320                                 ct = ip_vs_conn_new(svc->af, IPPROTO_IP,
321                                                     &snet, 0,
322                                                     &fwmark, 0,
323                                                     &dest->addr, 0,
324                                                     IP_VS_CONN_F_TEMPLATE,
325                                                     dest);
326                         } else
327                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
328                                                     &snet, 0,
329                                                     &iph.daddr, 0,
330                                                     &dest->addr, 0,
331                                                     IP_VS_CONN_F_TEMPLATE,
332                                                     dest);
333                         if (ct == NULL)
334                                 return NULL;
335
336                         ct->timeout = svc->timeout;
337                 } else {
338                         /* set destination with the found template */
339                         dest = ct->dest;
340                 }
341                 dport = ports[1];
342         }
343
344         flags = (svc->flags & IP_VS_SVC_F_ONEPACKET
345                  && iph.protocol == IPPROTO_UDP)?
346                 IP_VS_CONN_F_ONE_PACKET : 0;
347
348         /*
349          *    Create a new connection according to the template
350          */
351         cp = ip_vs_conn_new(svc->af, iph.protocol,
352                             &iph.saddr, ports[0],
353                             &iph.daddr, ports[1],
354                             &dest->addr, dport,
355                             flags,
356                             dest);
357         if (cp == NULL) {
358                 ip_vs_conn_put(ct);
359                 return NULL;
360         }
361
362         /*
363          *    Add its control
364          */
365         ip_vs_control_add(cp, ct);
366         ip_vs_conn_put(ct);
367
368         ip_vs_conn_stats(cp, svc);
369         return cp;
370 }
371
372
373 /*
374  *  IPVS main scheduling function
375  *  It selects a server according to the virtual service, and
376  *  creates a connection entry.
377  *  Protocols supported: TCP, UDP
378  */
379 struct ip_vs_conn *
380 ip_vs_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
381 {
382         struct ip_vs_conn *cp = NULL;
383         struct ip_vs_iphdr iph;
384         struct ip_vs_dest *dest;
385         __be16 _ports[2], *pptr, flags;
386
387         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
388         pptr = skb_header_pointer(skb, iph.len, sizeof(_ports), _ports);
389         if (pptr == NULL)
390                 return NULL;
391
392         /*
393          *    Persistent service
394          */
395         if (svc->flags & IP_VS_SVC_F_PERSISTENT)
396                 return ip_vs_sched_persist(svc, skb, pptr);
397
398         /*
399          *    Non-persistent service
400          */
401         if (!svc->fwmark && pptr[1] != svc->port) {
402                 if (!svc->port)
403                         pr_err("Schedule: port zero only supported "
404                                "in persistent services, "
405                                "check your ipvs configuration\n");
406                 return NULL;
407         }
408
409         dest = svc->scheduler->schedule(svc, skb);
410         if (dest == NULL) {
411                 IP_VS_DBG(1, "Schedule: no dest found.\n");
412                 return NULL;
413         }
414
415         flags = (svc->flags & IP_VS_SVC_F_ONEPACKET
416                  && iph.protocol == IPPROTO_UDP)?
417                 IP_VS_CONN_F_ONE_PACKET : 0;
418
419         /*
420          *    Create a connection entry.
421          */
422         cp = ip_vs_conn_new(svc->af, iph.protocol,
423                             &iph.saddr, pptr[0],
424                             &iph.daddr, pptr[1],
425                             &dest->addr, dest->port ? dest->port : pptr[1],
426                             flags,
427                             dest);
428         if (cp == NULL)
429                 return NULL;
430
431         IP_VS_DBG_BUF(6, "Schedule fwd:%c c:%s:%u v:%s:%u "
432                       "d:%s:%u conn->flags:%X conn->refcnt:%d\n",
433                       ip_vs_fwd_tag(cp),
434                       IP_VS_DBG_ADDR(svc->af, &cp->caddr), ntohs(cp->cport),
435                       IP_VS_DBG_ADDR(svc->af, &cp->vaddr), ntohs(cp->vport),
436                       IP_VS_DBG_ADDR(svc->af, &cp->daddr), ntohs(cp->dport),
437                       cp->flags, atomic_read(&cp->refcnt));
438
439         ip_vs_conn_stats(cp, svc);
440         return cp;
441 }
442
443
444 /*
445  *  Pass or drop the packet.
446  *  Called by ip_vs_in, when the virtual service is available but
447  *  no destination is available for a new connection.
448  */
449 int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
450                 struct ip_vs_protocol *pp)
451 {
452         __be16 _ports[2], *pptr;
453         struct ip_vs_iphdr iph;
454         int unicast;
455         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
456
457         pptr = skb_header_pointer(skb, iph.len, sizeof(_ports), _ports);
458         if (pptr == NULL) {
459                 ip_vs_service_put(svc);
460                 return NF_DROP;
461         }
462
463 #ifdef CONFIG_IP_VS_IPV6
464         if (svc->af == AF_INET6)
465                 unicast = ipv6_addr_type(&iph.daddr.in6) & IPV6_ADDR_UNICAST;
466         else
467 #endif
468                 unicast = (inet_addr_type(&init_net, iph.daddr.ip) == RTN_UNICAST);
469
470         /* if it is fwmark-based service, the cache_bypass sysctl is up
471            and the destination is a non-local unicast, then create
472            a cache_bypass connection entry */
473         if (sysctl_ip_vs_cache_bypass && svc->fwmark && unicast) {
474                 int ret, cs;
475                 struct ip_vs_conn *cp;
476                 __u16 flags = (svc->flags & IP_VS_SVC_F_ONEPACKET &&
477                                 iph.protocol == IPPROTO_UDP)?
478                                 IP_VS_CONN_F_ONE_PACKET : 0;
479                 union nf_inet_addr daddr =  { .all = { 0, 0, 0, 0 } };
480
481                 ip_vs_service_put(svc);
482
483                 /* create a new connection entry */
484                 IP_VS_DBG(6, "%s(): create a cache_bypass entry\n", __func__);
485                 cp = ip_vs_conn_new(svc->af, iph.protocol,
486                                     &iph.saddr, pptr[0],
487                                     &iph.daddr, pptr[1],
488                                     &daddr, 0,
489                                     IP_VS_CONN_F_BYPASS | flags,
490                                     NULL);
491                 if (cp == NULL)
492                         return NF_DROP;
493
494                 /* statistics */
495                 ip_vs_in_stats(cp, skb);
496
497                 /* set state */
498                 cs = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
499
500                 /* transmit the first SYN packet */
501                 ret = cp->packet_xmit(skb, cp, pp);
502                 /* do not touch skb anymore */
503
504                 atomic_inc(&cp->in_pkts);
505                 ip_vs_conn_put(cp);
506                 return ret;
507         }
508
509         /*
510          * When the virtual ftp service is presented, packets destined
511          * for other services on the VIP may get here (except services
512          * listed in the ipvs table), pass the packets, because it is
513          * not ipvs job to decide to drop the packets.
514          */
515         if ((svc->port == FTPPORT) && (pptr[1] != FTPPORT)) {
516                 ip_vs_service_put(svc);
517                 return NF_ACCEPT;
518         }
519
520         ip_vs_service_put(svc);
521
522         /*
523          * Notify the client that the destination is unreachable, and
524          * release the socket buffer.
525          * Since it is in IP layer, the TCP socket is not actually
526          * created, the TCP RST packet cannot be sent, instead that
527          * ICMP_PORT_UNREACH is sent here no matter it is TCP/UDP. --WZ
528          */
529 #ifdef CONFIG_IP_VS_IPV6
530         if (svc->af == AF_INET6)
531                 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
532         else
533 #endif
534                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
535
536         return NF_DROP;
537 }
538
539 __sum16 ip_vs_checksum_complete(struct sk_buff *skb, int offset)
540 {
541         return csum_fold(skb_checksum(skb, offset, skb->len - offset, 0));
542 }
543
544 static inline int ip_vs_gather_frags(struct sk_buff *skb, u_int32_t user)
545 {
546         int err = ip_defrag(skb, user);
547
548         if (!err)
549                 ip_send_check(ip_hdr(skb));
550
551         return err;
552 }
553
554 #ifdef CONFIG_IP_VS_IPV6
555 static inline int ip_vs_gather_frags_v6(struct sk_buff *skb, u_int32_t user)
556 {
557         /* TODO IPv6: Find out what to do here for IPv6 */
558         return 0;
559 }
560 #endif
561
562 /*
563  * Packet has been made sufficiently writable in caller
564  * - inout: 1=in->out, 0=out->in
565  */
566 void ip_vs_nat_icmp(struct sk_buff *skb, struct ip_vs_protocol *pp,
567                     struct ip_vs_conn *cp, int inout)
568 {
569         struct iphdr *iph        = ip_hdr(skb);
570         unsigned int icmp_offset = iph->ihl*4;
571         struct icmphdr *icmph    = (struct icmphdr *)(skb_network_header(skb) +
572                                                       icmp_offset);
573         struct iphdr *ciph       = (struct iphdr *)(icmph + 1);
574
575         if (inout) {
576                 iph->saddr = cp->vaddr.ip;
577                 ip_send_check(iph);
578                 ciph->daddr = cp->vaddr.ip;
579                 ip_send_check(ciph);
580         } else {
581                 iph->daddr = cp->daddr.ip;
582                 ip_send_check(iph);
583                 ciph->saddr = cp->daddr.ip;
584                 ip_send_check(ciph);
585         }
586
587         /* the TCP/UDP/SCTP port */
588         if (IPPROTO_TCP == ciph->protocol || IPPROTO_UDP == ciph->protocol ||
589             IPPROTO_SCTP == ciph->protocol) {
590                 __be16 *ports = (void *)ciph + ciph->ihl*4;
591
592                 if (inout)
593                         ports[1] = cp->vport;
594                 else
595                         ports[0] = cp->dport;
596         }
597
598         /* And finally the ICMP checksum */
599         icmph->checksum = 0;
600         icmph->checksum = ip_vs_checksum_complete(skb, icmp_offset);
601         skb->ip_summed = CHECKSUM_UNNECESSARY;
602
603         if (inout)
604                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
605                         "Forwarding altered outgoing ICMP");
606         else
607                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
608                         "Forwarding altered incoming ICMP");
609 }
610
611 #ifdef CONFIG_IP_VS_IPV6
612 void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct ip_vs_protocol *pp,
613                     struct ip_vs_conn *cp, int inout)
614 {
615         struct ipv6hdr *iph      = ipv6_hdr(skb);
616         unsigned int icmp_offset = sizeof(struct ipv6hdr);
617         struct icmp6hdr *icmph   = (struct icmp6hdr *)(skb_network_header(skb) +
618                                                       icmp_offset);
619         struct ipv6hdr *ciph     = (struct ipv6hdr *)(icmph + 1);
620
621         if (inout) {
622                 iph->saddr = cp->vaddr.in6;
623                 ciph->daddr = cp->vaddr.in6;
624         } else {
625                 iph->daddr = cp->daddr.in6;
626                 ciph->saddr = cp->daddr.in6;
627         }
628
629         /* the TCP/UDP/SCTP port */
630         if (IPPROTO_TCP == ciph->nexthdr || IPPROTO_UDP == ciph->nexthdr ||
631             IPPROTO_SCTP == ciph->nexthdr) {
632                 __be16 *ports = (void *)ciph + sizeof(struct ipv6hdr);
633
634                 if (inout)
635                         ports[1] = cp->vport;
636                 else
637                         ports[0] = cp->dport;
638         }
639
640         /* And finally the ICMP checksum */
641         icmph->icmp6_cksum = ~csum_ipv6_magic(&iph->saddr, &iph->daddr,
642                                               skb->len - icmp_offset,
643                                               IPPROTO_ICMPV6, 0);
644         skb->csum_start = skb_network_header(skb) - skb->head + icmp_offset;
645         skb->csum_offset = offsetof(struct icmp6hdr, icmp6_cksum);
646         skb->ip_summed = CHECKSUM_PARTIAL;
647
648         if (inout)
649                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
650                         "Forwarding altered outgoing ICMPv6");
651         else
652                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
653                         "Forwarding altered incoming ICMPv6");
654 }
655 #endif
656
657 /* Handle relevant response ICMP messages - forward to the right
658  * destination host. Used for NAT and local client.
659  */
660 static int handle_response_icmp(int af, struct sk_buff *skb,
661                                 union nf_inet_addr *snet,
662                                 __u8 protocol, struct ip_vs_conn *cp,
663                                 struct ip_vs_protocol *pp,
664                                 unsigned int offset, unsigned int ihl)
665 {
666         unsigned int verdict = NF_DROP;
667
668         if (IP_VS_FWD_METHOD(cp) != 0) {
669                 pr_err("shouldn't reach here, because the box is on the "
670                        "half connection in the tun/dr module.\n");
671         }
672
673         /* Ensure the checksum is correct */
674         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
675                 /* Failed checksum! */
676                 IP_VS_DBG_BUF(1, "Forward ICMP: failed checksum from %s!\n",
677                               IP_VS_DBG_ADDR(af, snet));
678                 goto out;
679         }
680
681         if (IPPROTO_TCP == protocol || IPPROTO_UDP == protocol ||
682             IPPROTO_SCTP == protocol)
683                 offset += 2 * sizeof(__u16);
684         if (!skb_make_writable(skb, offset))
685                 goto out;
686
687 #ifdef CONFIG_IP_VS_IPV6
688         if (af == AF_INET6)
689                 ip_vs_nat_icmp_v6(skb, pp, cp, 1);
690         else
691 #endif
692                 ip_vs_nat_icmp(skb, pp, cp, 1);
693
694         /* do the statistics and put it back */
695         ip_vs_out_stats(cp, skb);
696
697         skb->ipvs_property = 1;
698         verdict = NF_ACCEPT;
699
700 out:
701         __ip_vs_conn_put(cp);
702
703         return verdict;
704 }
705
706 /*
707  *      Handle ICMP messages in the inside-to-outside direction (outgoing).
708  *      Find any that might be relevant, check against existing connections.
709  *      Currently handles error types - unreachable, quench, ttl exceeded.
710  */
711 static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
712 {
713         struct iphdr *iph;
714         struct icmphdr  _icmph, *ic;
715         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
716         struct ip_vs_iphdr ciph;
717         struct ip_vs_conn *cp;
718         struct ip_vs_protocol *pp;
719         unsigned int offset, ihl;
720         union nf_inet_addr snet;
721
722         *related = 1;
723
724         /* reassemble IP fragments */
725         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
726                 if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
727                         return NF_STOLEN;
728         }
729
730         iph = ip_hdr(skb);
731         offset = ihl = iph->ihl * 4;
732         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
733         if (ic == NULL)
734                 return NF_DROP;
735
736         IP_VS_DBG(12, "Outgoing ICMP (%d,%d) %pI4->%pI4\n",
737                   ic->type, ntohs(icmp_id(ic)),
738                   &iph->saddr, &iph->daddr);
739
740         /*
741          * Work through seeing if this is for us.
742          * These checks are supposed to be in an order that means easy
743          * things are checked first to speed up processing.... however
744          * this means that some packets will manage to get a long way
745          * down this stack and then be rejected, but that's life.
746          */
747         if ((ic->type != ICMP_DEST_UNREACH) &&
748             (ic->type != ICMP_SOURCE_QUENCH) &&
749             (ic->type != ICMP_TIME_EXCEEDED)) {
750                 *related = 0;
751                 return NF_ACCEPT;
752         }
753
754         /* Now find the contained IP header */
755         offset += sizeof(_icmph);
756         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
757         if (cih == NULL)
758                 return NF_ACCEPT; /* The packet looks wrong, ignore */
759
760         pp = ip_vs_proto_get(cih->protocol);
761         if (!pp)
762                 return NF_ACCEPT;
763
764         /* Is the embedded protocol header present? */
765         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
766                      pp->dont_defrag))
767                 return NF_ACCEPT;
768
769         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMP for");
770
771         offset += cih->ihl * 4;
772
773         ip_vs_fill_iphdr(AF_INET, cih, &ciph);
774         /* The embedded headers contain source and dest in reverse order */
775         cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1);
776         if (!cp)
777                 return NF_ACCEPT;
778
779         snet.ip = iph->saddr;
780         return handle_response_icmp(AF_INET, skb, &snet, cih->protocol, cp,
781                                     pp, offset, ihl);
782 }
783
784 #ifdef CONFIG_IP_VS_IPV6
785 static int ip_vs_out_icmp_v6(struct sk_buff *skb, int *related)
786 {
787         struct ipv6hdr *iph;
788         struct icmp6hdr _icmph, *ic;
789         struct ipv6hdr  _ciph, *cih;    /* The ip header contained
790                                            within the ICMP */
791         struct ip_vs_iphdr ciph;
792         struct ip_vs_conn *cp;
793         struct ip_vs_protocol *pp;
794         unsigned int offset;
795         union nf_inet_addr snet;
796
797         *related = 1;
798
799         /* reassemble IP fragments */
800         if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
801                 if (ip_vs_gather_frags_v6(skb, IP_DEFRAG_VS_OUT))
802                         return NF_STOLEN;
803         }
804
805         iph = ipv6_hdr(skb);
806         offset = sizeof(struct ipv6hdr);
807         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
808         if (ic == NULL)
809                 return NF_DROP;
810
811         IP_VS_DBG(12, "Outgoing ICMPv6 (%d,%d) %pI6->%pI6\n",
812                   ic->icmp6_type, ntohs(icmpv6_id(ic)),
813                   &iph->saddr, &iph->daddr);
814
815         /*
816          * Work through seeing if this is for us.
817          * These checks are supposed to be in an order that means easy
818          * things are checked first to speed up processing.... however
819          * this means that some packets will manage to get a long way
820          * down this stack and then be rejected, but that's life.
821          */
822         if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
823             (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
824             (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
825                 *related = 0;
826                 return NF_ACCEPT;
827         }
828
829         /* Now find the contained IP header */
830         offset += sizeof(_icmph);
831         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
832         if (cih == NULL)
833                 return NF_ACCEPT; /* The packet looks wrong, ignore */
834
835         pp = ip_vs_proto_get(cih->nexthdr);
836         if (!pp)
837                 return NF_ACCEPT;
838
839         /* Is the embedded protocol header present? */
840         /* TODO: we don't support fragmentation at the moment anyways */
841         if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
842                 return NF_ACCEPT;
843
844         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMPv6 for");
845
846         offset += sizeof(struct ipv6hdr);
847
848         ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
849         /* The embedded headers contain source and dest in reverse order */
850         cp = pp->conn_out_get(AF_INET6, skb, pp, &ciph, offset, 1);
851         if (!cp)
852                 return NF_ACCEPT;
853
854         ipv6_addr_copy(&snet.in6, &iph->saddr);
855         return handle_response_icmp(AF_INET6, skb, &snet, cih->nexthdr, cp,
856                                     pp, offset, sizeof(struct ipv6hdr));
857 }
858 #endif
859
860 /*
861  * Check if sctp chunc is ABORT chunk
862  */
863 static inline int is_sctp_abort(const struct sk_buff *skb, int nh_len)
864 {
865         sctp_chunkhdr_t *sch, schunk;
866         sch = skb_header_pointer(skb, nh_len + sizeof(sctp_sctphdr_t),
867                         sizeof(schunk), &schunk);
868         if (sch == NULL)
869                 return 0;
870         if (sch->type == SCTP_CID_ABORT)
871                 return 1;
872         return 0;
873 }
874
875 static inline int is_tcp_reset(const struct sk_buff *skb, int nh_len)
876 {
877         struct tcphdr _tcph, *th;
878
879         th = skb_header_pointer(skb, nh_len, sizeof(_tcph), &_tcph);
880         if (th == NULL)
881                 return 0;
882         return th->rst;
883 }
884
885 /* Handle response packets: rewrite addresses and send away...
886  * Used for NAT and local client.
887  */
888 static unsigned int
889 handle_response(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
890                 struct ip_vs_conn *cp, int ihl)
891 {
892         IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet");
893
894         if (!skb_make_writable(skb, ihl))
895                 goto drop;
896
897         /* mangle the packet */
898         if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
899                 goto drop;
900
901 #ifdef CONFIG_IP_VS_IPV6
902         if (af == AF_INET6)
903                 ipv6_hdr(skb)->saddr = cp->vaddr.in6;
904         else
905 #endif
906         {
907                 ip_hdr(skb)->saddr = cp->vaddr.ip;
908                 ip_send_check(ip_hdr(skb));
909         }
910
911         /* For policy routing, packets originating from this
912          * machine itself may be routed differently to packets
913          * passing through.  We want this packet to be routed as
914          * if it came from this machine itself.  So re-compute
915          * the routing information.
916          */
917 #ifdef CONFIG_IP_VS_IPV6
918         if (af == AF_INET6) {
919                 if (ip6_route_me_harder(skb) != 0)
920                         goto drop;
921         } else
922 #endif
923                 if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
924                         goto drop;
925
926         IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
927
928         ip_vs_out_stats(cp, skb);
929         ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
930         ip_vs_update_conntrack(skb, cp, 0);
931         ip_vs_conn_put(cp);
932
933         skb->ipvs_property = 1;
934
935         LeaveFunction(11);
936         return NF_ACCEPT;
937
938 drop:
939         ip_vs_conn_put(cp);
940         kfree_skb(skb);
941         return NF_STOLEN;
942 }
943
944 /*
945  *      It is hooked at the NF_INET_FORWARD chain, used only for VS/NAT.
946  *      Check if outgoing packet belongs to the established ip_vs_conn.
947  */
948 static unsigned int
949 ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
950           const struct net_device *in, const struct net_device *out,
951           int (*okfn)(struct sk_buff *))
952 {
953         struct ip_vs_iphdr iph;
954         struct ip_vs_protocol *pp;
955         struct ip_vs_conn *cp;
956         int af;
957
958         EnterFunction(11);
959
960         af = (skb->protocol == htons(ETH_P_IP)) ? AF_INET : AF_INET6;
961
962         if (skb->ipvs_property)
963                 return NF_ACCEPT;
964
965         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
966 #ifdef CONFIG_IP_VS_IPV6
967         if (af == AF_INET6) {
968                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
969                         int related, verdict = ip_vs_out_icmp_v6(skb, &related);
970
971                         if (related)
972                                 return verdict;
973                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
974                 }
975         } else
976 #endif
977                 if (unlikely(iph.protocol == IPPROTO_ICMP)) {
978                         int related, verdict = ip_vs_out_icmp(skb, &related);
979
980                         if (related)
981                                 return verdict;
982                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
983                 }
984
985         pp = ip_vs_proto_get(iph.protocol);
986         if (unlikely(!pp))
987                 return NF_ACCEPT;
988
989         /* reassemble IP fragments */
990 #ifdef CONFIG_IP_VS_IPV6
991         if (af == AF_INET6) {
992                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
993                         int related, verdict = ip_vs_out_icmp_v6(skb, &related);
994
995                         if (related)
996                                 return verdict;
997
998                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
999                 }
1000         } else
1001 #endif
1002                 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_MF|IP_OFFSET) &&
1003                              !pp->dont_defrag)) {
1004                         if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
1005                                 return NF_STOLEN;
1006
1007                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1008                 }
1009
1010         /*
1011          * Check if the packet belongs to an existing entry
1012          */
1013         cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
1014
1015         if (unlikely(!cp)) {
1016                 if (sysctl_ip_vs_nat_icmp_send &&
1017                     (pp->protocol == IPPROTO_TCP ||
1018                      pp->protocol == IPPROTO_UDP ||
1019                      pp->protocol == IPPROTO_SCTP)) {
1020                         __be16 _ports[2], *pptr;
1021
1022                         pptr = skb_header_pointer(skb, iph.len,
1023                                                   sizeof(_ports), _ports);
1024                         if (pptr == NULL)
1025                                 return NF_ACCEPT;       /* Not for me */
1026                         if (ip_vs_lookup_real_service(af, iph.protocol,
1027                                                       &iph.saddr,
1028                                                       pptr[0])) {
1029                                 /*
1030                                  * Notify the real server: there is no
1031                                  * existing entry if it is not RST
1032                                  * packet or not TCP packet.
1033                                  */
1034                                 if ((iph.protocol != IPPROTO_TCP &&
1035                                      iph.protocol != IPPROTO_SCTP)
1036                                      || ((iph.protocol == IPPROTO_TCP
1037                                           && !is_tcp_reset(skb, iph.len))
1038                                          || (iph.protocol == IPPROTO_SCTP
1039                                                 && !is_sctp_abort(skb,
1040                                                         iph.len)))) {
1041 #ifdef CONFIG_IP_VS_IPV6
1042                                         if (af == AF_INET6)
1043                                                 icmpv6_send(skb,
1044                                                             ICMPV6_DEST_UNREACH,
1045                                                             ICMPV6_PORT_UNREACH,
1046                                                             0);
1047                                         else
1048 #endif
1049                                                 icmp_send(skb,
1050                                                           ICMP_DEST_UNREACH,
1051                                                           ICMP_PORT_UNREACH, 0);
1052                                         return NF_DROP;
1053                                 }
1054                         }
1055                 }
1056                 IP_VS_DBG_PKT(12, pp, skb, 0,
1057                               "packet continues traversal as normal");
1058                 return NF_ACCEPT;
1059         }
1060
1061         return handle_response(af, skb, pp, cp, iph.len);
1062 }
1063
1064
1065 /*
1066  *      Handle ICMP messages in the outside-to-inside direction (incoming).
1067  *      Find any that might be relevant, check against existing connections,
1068  *      forward to the right destination host if relevant.
1069  *      Currently handles error types - unreachable, quench, ttl exceeded.
1070  */
1071 static int
1072 ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
1073 {
1074         struct iphdr *iph;
1075         struct icmphdr  _icmph, *ic;
1076         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
1077         struct ip_vs_iphdr ciph;
1078         struct ip_vs_conn *cp;
1079         struct ip_vs_protocol *pp;
1080         unsigned int offset, ihl, verdict;
1081         union nf_inet_addr snet;
1082
1083         *related = 1;
1084
1085         /* reassemble IP fragments */
1086         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
1087                 if (ip_vs_gather_frags(skb, hooknum == NF_INET_LOCAL_IN ?
1088                                             IP_DEFRAG_VS_IN : IP_DEFRAG_VS_FWD))
1089                         return NF_STOLEN;
1090         }
1091
1092         iph = ip_hdr(skb);
1093         offset = ihl = iph->ihl * 4;
1094         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
1095         if (ic == NULL)
1096                 return NF_DROP;
1097
1098         IP_VS_DBG(12, "Incoming ICMP (%d,%d) %pI4->%pI4\n",
1099                   ic->type, ntohs(icmp_id(ic)),
1100                   &iph->saddr, &iph->daddr);
1101
1102         /*
1103          * Work through seeing if this is for us.
1104          * These checks are supposed to be in an order that means easy
1105          * things are checked first to speed up processing.... however
1106          * this means that some packets will manage to get a long way
1107          * down this stack and then be rejected, but that's life.
1108          */
1109         if ((ic->type != ICMP_DEST_UNREACH) &&
1110             (ic->type != ICMP_SOURCE_QUENCH) &&
1111             (ic->type != ICMP_TIME_EXCEEDED)) {
1112                 *related = 0;
1113                 return NF_ACCEPT;
1114         }
1115
1116         /* Now find the contained IP header */
1117         offset += sizeof(_icmph);
1118         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
1119         if (cih == NULL)
1120                 return NF_ACCEPT; /* The packet looks wrong, ignore */
1121
1122         pp = ip_vs_proto_get(cih->protocol);
1123         if (!pp)
1124                 return NF_ACCEPT;
1125
1126         /* Is the embedded protocol header present? */
1127         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
1128                      pp->dont_defrag))
1129                 return NF_ACCEPT;
1130
1131         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMP for");
1132
1133         offset += cih->ihl * 4;
1134
1135         ip_vs_fill_iphdr(AF_INET, cih, &ciph);
1136         /* The embedded headers contain source and dest in reverse order */
1137         cp = pp->conn_in_get(AF_INET, skb, pp, &ciph, offset, 1);
1138         if (!cp) {
1139                 /* The packet could also belong to a local client */
1140                 cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1);
1141                 if (cp) {
1142                         snet.ip = iph->saddr;
1143                         return handle_response_icmp(AF_INET, skb, &snet,
1144                                                     cih->protocol, cp, pp,
1145                                                     offset, ihl);
1146                 }
1147                 return NF_ACCEPT;
1148         }
1149
1150         verdict = NF_DROP;
1151
1152         /* Ensure the checksum is correct */
1153         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
1154                 /* Failed checksum! */
1155                 IP_VS_DBG(1, "Incoming ICMP: failed checksum from %pI4!\n",
1156                           &iph->saddr);
1157                 goto out;
1158         }
1159
1160         /* do the statistics and put it back */
1161         ip_vs_in_stats(cp, skb);
1162         if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
1163                 offset += 2 * sizeof(__u16);
1164         verdict = ip_vs_icmp_xmit(skb, cp, pp, offset);
1165         /* do not touch skb anymore */
1166
1167   out:
1168         __ip_vs_conn_put(cp);
1169
1170         return verdict;
1171 }
1172
1173 #ifdef CONFIG_IP_VS_IPV6
1174 static int
1175 ip_vs_in_icmp_v6(struct sk_buff *skb, int *related, unsigned int hooknum)
1176 {
1177         struct ipv6hdr *iph;
1178         struct icmp6hdr _icmph, *ic;
1179         struct ipv6hdr  _ciph, *cih;    /* The ip header contained
1180                                            within the ICMP */
1181         struct ip_vs_iphdr ciph;
1182         struct ip_vs_conn *cp;
1183         struct ip_vs_protocol *pp;
1184         unsigned int offset, verdict;
1185         union nf_inet_addr snet;
1186
1187         *related = 1;
1188
1189         /* reassemble IP fragments */
1190         if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
1191                 if (ip_vs_gather_frags_v6(skb, hooknum == NF_INET_LOCAL_IN ?
1192                                                IP_DEFRAG_VS_IN :
1193                                                IP_DEFRAG_VS_FWD))
1194                         return NF_STOLEN;
1195         }
1196
1197         iph = ipv6_hdr(skb);
1198         offset = sizeof(struct ipv6hdr);
1199         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
1200         if (ic == NULL)
1201                 return NF_DROP;
1202
1203         IP_VS_DBG(12, "Incoming ICMPv6 (%d,%d) %pI6->%pI6\n",
1204                   ic->icmp6_type, ntohs(icmpv6_id(ic)),
1205                   &iph->saddr, &iph->daddr);
1206
1207         /*
1208          * Work through seeing if this is for us.
1209          * These checks are supposed to be in an order that means easy
1210          * things are checked first to speed up processing.... however
1211          * this means that some packets will manage to get a long way
1212          * down this stack and then be rejected, but that's life.
1213          */
1214         if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
1215             (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
1216             (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
1217                 *related = 0;
1218                 return NF_ACCEPT;
1219         }
1220
1221         /* Now find the contained IP header */
1222         offset += sizeof(_icmph);
1223         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
1224         if (cih == NULL)
1225                 return NF_ACCEPT; /* The packet looks wrong, ignore */
1226
1227         pp = ip_vs_proto_get(cih->nexthdr);
1228         if (!pp)
1229                 return NF_ACCEPT;
1230
1231         /* Is the embedded protocol header present? */
1232         /* TODO: we don't support fragmentation at the moment anyways */
1233         if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
1234                 return NF_ACCEPT;
1235
1236         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMPv6 for");
1237
1238         offset += sizeof(struct ipv6hdr);
1239
1240         ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
1241         /* The embedded headers contain source and dest in reverse order */
1242         cp = pp->conn_in_get(AF_INET6, skb, pp, &ciph, offset, 1);
1243         if (!cp) {
1244                 /* The packet could also belong to a local client */
1245                 cp = pp->conn_out_get(AF_INET6, skb, pp, &ciph, offset, 1);
1246                 if (cp) {
1247                         ipv6_addr_copy(&snet.in6, &iph->saddr);
1248                         return handle_response_icmp(AF_INET6, skb, &snet,
1249                                                     cih->nexthdr,
1250                                                     cp, pp, offset,
1251                                                     sizeof(struct ipv6hdr));
1252                 }
1253                 return NF_ACCEPT;
1254         }
1255
1256         verdict = NF_DROP;
1257
1258         /* do the statistics and put it back */
1259         ip_vs_in_stats(cp, skb);
1260         if (IPPROTO_TCP == cih->nexthdr || IPPROTO_UDP == cih->nexthdr ||
1261             IPPROTO_SCTP == cih->nexthdr)
1262                 offset += 2 * sizeof(__u16);
1263         verdict = ip_vs_icmp_xmit_v6(skb, cp, pp, offset);
1264         /* do not touch skb anymore */
1265
1266         __ip_vs_conn_put(cp);
1267
1268         return verdict;
1269 }
1270 #endif
1271
1272
1273 /*
1274  *      Check if it's for virtual services, look it up,
1275  *      and send it on its way...
1276  */
1277 static unsigned int
1278 ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
1279          const struct net_device *in, const struct net_device *out,
1280          int (*okfn)(struct sk_buff *))
1281 {
1282         struct ip_vs_iphdr iph;
1283         struct ip_vs_protocol *pp;
1284         struct ip_vs_conn *cp;
1285         int ret, restart, af, pkts;
1286
1287         af = (skb->protocol == htons(ETH_P_IP)) ? AF_INET : AF_INET6;
1288
1289         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1290
1291         /*
1292          *      Big tappo: only PACKET_HOST, including loopback for local client
1293          *      Don't handle local packets on IPv6 for now
1294          */
1295         if (unlikely(skb->pkt_type != PACKET_HOST)) {
1296                 IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s ignored\n",
1297                               skb->pkt_type,
1298                               iph.protocol,
1299                               IP_VS_DBG_ADDR(af, &iph.daddr));
1300                 return NF_ACCEPT;
1301         }
1302
1303 #ifdef CONFIG_IP_VS_IPV6
1304         if (af == AF_INET6) {
1305                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
1306                         int related, verdict = ip_vs_in_icmp_v6(skb, &related, hooknum);
1307
1308                         if (related)
1309                                 return verdict;
1310                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1311                 }
1312         } else
1313 #endif
1314                 if (unlikely(iph.protocol == IPPROTO_ICMP)) {
1315                         int related, verdict = ip_vs_in_icmp(skb, &related, hooknum);
1316
1317                         if (related)
1318                                 return verdict;
1319                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1320                 }
1321
1322         /* Protocol supported? */
1323         pp = ip_vs_proto_get(iph.protocol);
1324         if (unlikely(!pp))
1325                 return NF_ACCEPT;
1326
1327         /*
1328          * Check if the packet belongs to an existing connection entry
1329          */
1330         cp = pp->conn_in_get(af, skb, pp, &iph, iph.len, 0);
1331
1332         if (unlikely(!cp)) {
1333                 int v;
1334
1335                 /* For local client packets, it could be a response */
1336                 cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
1337                 if (cp)
1338                         return handle_response(af, skb, pp, cp, iph.len);
1339
1340                 if (!pp->conn_schedule(af, skb, pp, &v, &cp))
1341                         return v;
1342         }
1343
1344         if (unlikely(!cp)) {
1345                 /* sorry, all this trouble for a no-hit :) */
1346                 IP_VS_DBG_PKT(12, pp, skb, 0,
1347                               "packet continues traversal as normal");
1348                 return NF_ACCEPT;
1349         }
1350
1351         IP_VS_DBG_PKT(11, pp, skb, 0, "Incoming packet");
1352
1353         /* Check the server status */
1354         if (cp->dest && !(cp->dest->flags & IP_VS_DEST_F_AVAILABLE)) {
1355                 /* the destination server is not available */
1356
1357                 if (sysctl_ip_vs_expire_nodest_conn) {
1358                         /* try to expire the connection immediately */
1359                         ip_vs_conn_expire_now(cp);
1360                 }
1361                 /* don't restart its timer, and silently
1362                    drop the packet. */
1363                 __ip_vs_conn_put(cp);
1364                 return NF_DROP;
1365         }
1366
1367         ip_vs_in_stats(cp, skb);
1368         restart = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
1369         if (cp->packet_xmit)
1370                 ret = cp->packet_xmit(skb, cp, pp);
1371                 /* do not touch skb anymore */
1372         else {
1373                 IP_VS_DBG_RL("warning: packet_xmit is null");
1374                 ret = NF_ACCEPT;
1375         }
1376
1377         /* Increase its packet counter and check if it is needed
1378          * to be synchronized
1379          *
1380          * Sync connection if it is about to close to
1381          * encorage the standby servers to update the connections timeout
1382          */
1383         pkts = atomic_add_return(1, &cp->in_pkts);
1384         if (af == AF_INET && (ip_vs_sync_state & IP_VS_STATE_MASTER) &&
1385             cp->protocol == IPPROTO_SCTP) {
1386                 if ((cp->state == IP_VS_SCTP_S_ESTABLISHED &&
1387                         (pkts % sysctl_ip_vs_sync_threshold[1]
1388                          == sysctl_ip_vs_sync_threshold[0])) ||
1389                                 (cp->old_state != cp->state &&
1390                                  ((cp->state == IP_VS_SCTP_S_CLOSED) ||
1391                                   (cp->state == IP_VS_SCTP_S_SHUT_ACK_CLI) ||
1392                                   (cp->state == IP_VS_SCTP_S_SHUT_ACK_SER)))) {
1393                         ip_vs_sync_conn(cp);
1394                         goto out;
1395                 }
1396         }
1397
1398         /* Keep this block last: TCP and others with pp->num_states <= 1 */
1399         else if (af == AF_INET &&
1400             (ip_vs_sync_state & IP_VS_STATE_MASTER) &&
1401             (((cp->protocol != IPPROTO_TCP ||
1402                cp->state == IP_VS_TCP_S_ESTABLISHED) &&
1403               (pkts % sysctl_ip_vs_sync_threshold[1]
1404                == sysctl_ip_vs_sync_threshold[0])) ||
1405              ((cp->protocol == IPPROTO_TCP) && (cp->old_state != cp->state) &&
1406               ((cp->state == IP_VS_TCP_S_FIN_WAIT) ||
1407                (cp->state == IP_VS_TCP_S_CLOSE) ||
1408                (cp->state == IP_VS_TCP_S_CLOSE_WAIT) ||
1409                (cp->state == IP_VS_TCP_S_TIME_WAIT)))))
1410                 ip_vs_sync_conn(cp);
1411 out:
1412         cp->old_state = cp->state;
1413
1414         ip_vs_conn_put(cp);
1415         return ret;
1416 }
1417
1418
1419 /*
1420  *      It is hooked at the NF_INET_FORWARD chain, in order to catch ICMP
1421  *      related packets destined for 0.0.0.0/0.
1422  *      When fwmark-based virtual service is used, such as transparent
1423  *      cache cluster, TCP packets can be marked and routed to ip_vs_in,
1424  *      but ICMP destined for 0.0.0.0/0 cannot not be easily marked and
1425  *      sent to ip_vs_in_icmp. So, catch them at the NF_INET_FORWARD chain
1426  *      and send them to ip_vs_in_icmp.
1427  */
1428 static unsigned int
1429 ip_vs_forward_icmp(unsigned int hooknum, struct sk_buff *skb,
1430                    const struct net_device *in, const struct net_device *out,
1431                    int (*okfn)(struct sk_buff *))
1432 {
1433         int r;
1434
1435         if (ip_hdr(skb)->protocol != IPPROTO_ICMP)
1436                 return NF_ACCEPT;
1437
1438         return ip_vs_in_icmp(skb, &r, hooknum);
1439 }
1440
1441 #ifdef CONFIG_IP_VS_IPV6
1442 static unsigned int
1443 ip_vs_forward_icmp_v6(unsigned int hooknum, struct sk_buff *skb,
1444                       const struct net_device *in, const struct net_device *out,
1445                       int (*okfn)(struct sk_buff *))
1446 {
1447         int r;
1448
1449         if (ipv6_hdr(skb)->nexthdr != IPPROTO_ICMPV6)
1450                 return NF_ACCEPT;
1451
1452         return ip_vs_in_icmp_v6(skb, &r, hooknum);
1453 }
1454 #endif
1455
1456
1457 static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
1458         /* After packet filtering, forward packet through VS/DR, VS/TUN,
1459          * or VS/NAT(change destination), so that filtering rules can be
1460          * applied to IPVS. */
1461         {
1462                 .hook           = ip_vs_in,
1463                 .owner          = THIS_MODULE,
1464                 .pf             = PF_INET,
1465                 .hooknum        = NF_INET_LOCAL_IN,
1466                 .priority       = 100,
1467         },
1468         /* After packet filtering, change source only for VS/NAT */
1469         {
1470                 .hook           = ip_vs_out,
1471                 .owner          = THIS_MODULE,
1472                 .pf             = PF_INET,
1473                 .hooknum        = NF_INET_FORWARD,
1474                 .priority       = 100,
1475         },
1476         /* After packet filtering (but before ip_vs_out_icmp), catch icmp
1477          * destined for 0.0.0.0/0, which is for incoming IPVS connections */
1478         {
1479                 .hook           = ip_vs_forward_icmp,
1480                 .owner          = THIS_MODULE,
1481                 .pf             = PF_INET,
1482                 .hooknum        = NF_INET_FORWARD,
1483                 .priority       = 99,
1484         },
1485 #ifdef CONFIG_IP_VS_IPV6
1486         /* After packet filtering, forward packet through VS/DR, VS/TUN,
1487          * or VS/NAT(change destination), so that filtering rules can be
1488          * applied to IPVS. */
1489         {
1490                 .hook           = ip_vs_in,
1491                 .owner          = THIS_MODULE,
1492                 .pf             = PF_INET6,
1493                 .hooknum        = NF_INET_LOCAL_IN,
1494                 .priority       = 100,
1495         },
1496         /* After packet filtering, change source only for VS/NAT */
1497         {
1498                 .hook           = ip_vs_out,
1499                 .owner          = THIS_MODULE,
1500                 .pf             = PF_INET6,
1501                 .hooknum        = NF_INET_FORWARD,
1502                 .priority       = 100,
1503         },
1504         /* After packet filtering (but before ip_vs_out_icmp), catch icmp
1505          * destined for 0.0.0.0/0, which is for incoming IPVS connections */
1506         {
1507                 .hook           = ip_vs_forward_icmp_v6,
1508                 .owner          = THIS_MODULE,
1509                 .pf             = PF_INET6,
1510                 .hooknum        = NF_INET_FORWARD,
1511                 .priority       = 99,
1512         },
1513 #endif
1514 };
1515
1516
1517 /*
1518  *      Initialize IP Virtual Server
1519  */
1520 static int __init ip_vs_init(void)
1521 {
1522         int ret;
1523
1524         ip_vs_estimator_init();
1525
1526         ret = ip_vs_control_init();
1527         if (ret < 0) {
1528                 pr_err("can't setup control.\n");
1529                 goto cleanup_estimator;
1530         }
1531
1532         ip_vs_protocol_init();
1533
1534         ret = ip_vs_app_init();
1535         if (ret < 0) {
1536                 pr_err("can't setup application helper.\n");
1537                 goto cleanup_protocol;
1538         }
1539
1540         ret = ip_vs_conn_init();
1541         if (ret < 0) {
1542                 pr_err("can't setup connection table.\n");
1543                 goto cleanup_app;
1544         }
1545
1546         ret = nf_register_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1547         if (ret < 0) {
1548                 pr_err("can't register hooks.\n");
1549                 goto cleanup_conn;
1550         }
1551
1552         pr_info("ipvs loaded.\n");
1553         return ret;
1554
1555   cleanup_conn:
1556         ip_vs_conn_cleanup();
1557   cleanup_app:
1558         ip_vs_app_cleanup();
1559   cleanup_protocol:
1560         ip_vs_protocol_cleanup();
1561         ip_vs_control_cleanup();
1562   cleanup_estimator:
1563         ip_vs_estimator_cleanup();
1564         return ret;
1565 }
1566
1567 static void __exit ip_vs_cleanup(void)
1568 {
1569         nf_unregister_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1570         ip_vs_conn_cleanup();
1571         ip_vs_app_cleanup();
1572         ip_vs_protocol_cleanup();
1573         ip_vs_control_cleanup();
1574         ip_vs_estimator_cleanup();
1575         pr_info("ipvs unloaded.\n");
1576 }
1577
1578 module_init(ip_vs_init);
1579 module_exit(ip_vs_cleanup);
1580 MODULE_LICENSE("GPL");