2 * ip_vs_app.c: Application module support for IPVS
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * Most code here is taken from ip_masq_app.c in kernel 2.2. The difference
12 * is that ip_vs_app module handles the reverse direction (incoming requests
13 * and outgoing responses).
15 * IP_MASQ_APP application masquerading module
17 * Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar>
21 #define KMSG_COMPONENT "IPVS"
22 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/skbuff.h>
29 #include <linux/netfilter.h>
30 #include <linux/slab.h>
31 #include <net/net_namespace.h>
32 #include <net/protocol.h>
34 #include <linux/stat.h>
35 #include <linux/proc_fs.h>
36 #include <linux/seq_file.h>
37 #include <linux/mutex.h>
39 #include <net/ip_vs.h>
41 EXPORT_SYMBOL(register_ip_vs_app
);
42 EXPORT_SYMBOL(unregister_ip_vs_app
);
43 EXPORT_SYMBOL(register_ip_vs_app_inc
);
45 static DEFINE_MUTEX(__ip_vs_app_mutex
);
48 * Get an ip_vs_app object
50 static inline int ip_vs_app_get(struct ip_vs_app
*app
)
52 return try_module_get(app
->module
);
56 static inline void ip_vs_app_put(struct ip_vs_app
*app
)
58 module_put(app
->module
);
61 static void ip_vs_app_inc_destroy(struct ip_vs_app
*inc
)
63 kfree(inc
->timeout_table
);
67 static void ip_vs_app_inc_rcu_free(struct rcu_head
*head
)
69 struct ip_vs_app
*inc
= container_of(head
, struct ip_vs_app
, rcu_head
);
71 ip_vs_app_inc_destroy(inc
);
75 * Allocate/initialize app incarnation and register it in proto apps.
78 ip_vs_app_inc_new(struct netns_ipvs
*ipvs
, struct ip_vs_app
*app
, __u16 proto
,
81 struct ip_vs_protocol
*pp
;
82 struct ip_vs_app
*inc
;
85 if (!(pp
= ip_vs_proto_get(proto
)))
86 return -EPROTONOSUPPORT
;
88 if (!pp
->unregister_app
)
91 inc
= kmemdup(app
, sizeof(*inc
), GFP_KERNEL
);
94 INIT_LIST_HEAD(&inc
->p_list
);
95 INIT_LIST_HEAD(&inc
->incs_list
);
97 inc
->port
= htons(port
);
98 atomic_set(&inc
->usecnt
, 0);
102 ip_vs_create_timeout_table(app
->timeouts
,
104 if (!inc
->timeout_table
) {
110 ret
= pp
->register_app(ipvs
, inc
);
114 list_add(&inc
->a_list
, &app
->incs_list
);
115 IP_VS_DBG(9, "%s App %s:%u registered\n",
116 pp
->name
, inc
->name
, ntohs(inc
->port
));
121 ip_vs_app_inc_destroy(inc
);
127 * Release app incarnation
130 ip_vs_app_inc_release(struct netns_ipvs
*ipvs
, struct ip_vs_app
*inc
)
132 struct ip_vs_protocol
*pp
;
134 if (!(pp
= ip_vs_proto_get(inc
->protocol
)))
137 if (pp
->unregister_app
)
138 pp
->unregister_app(ipvs
, inc
);
140 IP_VS_DBG(9, "%s App %s:%u unregistered\n",
141 pp
->name
, inc
->name
, ntohs(inc
->port
));
143 list_del(&inc
->a_list
);
145 call_rcu(&inc
->rcu_head
, ip_vs_app_inc_rcu_free
);
150 * Get reference to app inc (only called from softirq)
153 int ip_vs_app_inc_get(struct ip_vs_app
*inc
)
157 result
= ip_vs_app_get(inc
->app
);
159 atomic_inc(&inc
->usecnt
);
165 * Put the app inc (only called from timer or net softirq)
167 void ip_vs_app_inc_put(struct ip_vs_app
*inc
)
169 atomic_dec(&inc
->usecnt
);
170 ip_vs_app_put(inc
->app
);
175 * Register an application incarnation in protocol applications
178 register_ip_vs_app_inc(struct netns_ipvs
*ipvs
, struct ip_vs_app
*app
, __u16 proto
,
183 mutex_lock(&__ip_vs_app_mutex
);
185 result
= ip_vs_app_inc_new(ipvs
, app
, proto
, port
);
187 mutex_unlock(&__ip_vs_app_mutex
);
193 /* Register application for netns */
194 struct ip_vs_app
*register_ip_vs_app(struct netns_ipvs
*ipvs
, struct ip_vs_app
*app
)
199 mutex_lock(&__ip_vs_app_mutex
);
201 list_for_each_entry(a
, &ipvs
->app_list
, a_list
) {
202 if (!strcmp(app
->name
, a
->name
)) {
207 a
= kmemdup(app
, sizeof(*app
), GFP_KERNEL
);
212 INIT_LIST_HEAD(&a
->incs_list
);
213 list_add(&a
->a_list
, &ipvs
->app_list
);
214 /* increase the module use count */
215 ip_vs_use_count_inc();
218 mutex_unlock(&__ip_vs_app_mutex
);
220 return err
? ERR_PTR(err
) : a
;
225 * ip_vs_app unregistration routine
226 * We are sure there are no app incarnations attached to services
227 * Caller should use synchronize_rcu() or rcu_barrier()
229 void unregister_ip_vs_app(struct netns_ipvs
*ipvs
, struct ip_vs_app
*app
)
231 struct ip_vs_app
*a
, *anxt
, *inc
, *nxt
;
233 mutex_lock(&__ip_vs_app_mutex
);
235 list_for_each_entry_safe(a
, anxt
, &ipvs
->app_list
, a_list
) {
236 if (app
&& strcmp(app
->name
, a
->name
))
238 list_for_each_entry_safe(inc
, nxt
, &a
->incs_list
, a_list
) {
239 ip_vs_app_inc_release(ipvs
, inc
);
242 list_del(&a
->a_list
);
245 /* decrease the module use count */
246 ip_vs_use_count_dec();
249 mutex_unlock(&__ip_vs_app_mutex
);
254 * Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
256 int ip_vs_bind_app(struct ip_vs_conn
*cp
,
257 struct ip_vs_protocol
*pp
)
259 return pp
->app_conn_bind(cp
);
264 * Unbind cp from application incarnation (called by cp destructor)
266 void ip_vs_unbind_app(struct ip_vs_conn
*cp
)
268 struct ip_vs_app
*inc
= cp
->app
;
273 if (inc
->unbind_conn
)
274 inc
->unbind_conn(inc
, cp
);
276 inc
->done_conn(inc
, cp
);
277 ip_vs_app_inc_put(inc
);
283 * Fixes th->seq based on ip_vs_seq info.
285 static inline void vs_fix_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
287 __u32 seq
= ntohl(th
->seq
);
290 * Adjust seq with delta-offset for all packets after
291 * the most recent resized pkt seq and with previous_delta offset
292 * for all packets before most recent resized pkt seq.
294 if (vseq
->delta
|| vseq
->previous_delta
) {
295 if(after(seq
, vseq
->init_seq
)) {
296 th
->seq
= htonl(seq
+ vseq
->delta
);
297 IP_VS_DBG(9, "%s(): added delta (%d) to seq\n",
298 __func__
, vseq
->delta
);
300 th
->seq
= htonl(seq
+ vseq
->previous_delta
);
301 IP_VS_DBG(9, "%s(): added previous_delta (%d) to seq\n",
302 __func__
, vseq
->previous_delta
);
309 * Fixes th->ack_seq based on ip_vs_seq info.
312 vs_fix_ack_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
314 __u32 ack_seq
= ntohl(th
->ack_seq
);
317 * Adjust ack_seq with delta-offset for
318 * the packets AFTER most recent resized pkt has caused a shift
319 * for packets before most recent resized pkt, use previous_delta
321 if (vseq
->delta
|| vseq
->previous_delta
) {
322 /* since ack_seq is the number of octet that is expected
323 to receive next, so compare it with init_seq+delta */
324 if(after(ack_seq
, vseq
->init_seq
+vseq
->delta
)) {
325 th
->ack_seq
= htonl(ack_seq
- vseq
->delta
);
326 IP_VS_DBG(9, "%s(): subtracted delta "
327 "(%d) from ack_seq\n", __func__
, vseq
->delta
);
330 th
->ack_seq
= htonl(ack_seq
- vseq
->previous_delta
);
331 IP_VS_DBG(9, "%s(): subtracted "
332 "previous_delta (%d) from ack_seq\n",
333 __func__
, vseq
->previous_delta
);
340 * Updates ip_vs_seq if pkt has been resized
341 * Assumes already checked proto==IPPROTO_TCP and diff!=0.
343 static inline void vs_seq_update(struct ip_vs_conn
*cp
, struct ip_vs_seq
*vseq
,
344 unsigned int flag
, __u32 seq
, int diff
)
346 /* spinlock is to keep updating cp->flags atomic */
347 spin_lock_bh(&cp
->lock
);
348 if (!(cp
->flags
& flag
) || after(seq
, vseq
->init_seq
)) {
349 vseq
->previous_delta
= vseq
->delta
;
351 vseq
->init_seq
= seq
;
354 spin_unlock_bh(&cp
->lock
);
357 static inline int app_tcp_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
358 struct ip_vs_app
*app
)
361 const unsigned int tcp_offset
= ip_hdrlen(skb
);
365 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
368 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
371 * Remember seq number in case this pkt gets resized
373 seq
= ntohl(th
->seq
);
376 * Fix seq stuff if flagged as so.
378 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
379 vs_fix_seq(&cp
->out_seq
, th
);
380 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
381 vs_fix_ack_seq(&cp
->in_seq
, th
);
384 * Call private output hook function
386 if (app
->pkt_out
== NULL
)
389 if (!app
->pkt_out(app
, cp
, skb
, &diff
))
393 * Update ip_vs seq stuff if len has changed.
396 vs_seq_update(cp
, &cp
->out_seq
,
397 IP_VS_CONN_F_OUT_SEQ
, seq
, diff
);
403 * Output pkt hook. Will call bound ip_vs_app specific function
404 * called by ipvs packet handler, assumes previously checked cp!=NULL
405 * returns false if it can't handle packet (oom)
407 int ip_vs_app_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
409 struct ip_vs_app
*app
;
412 * check if application module is bound to
415 if ((app
= cp
->app
) == NULL
)
418 /* TCP is complicated */
419 if (cp
->protocol
== IPPROTO_TCP
)
420 return app_tcp_pkt_out(cp
, skb
, app
);
423 * Call private output hook function
425 if (app
->pkt_out
== NULL
)
428 return app
->pkt_out(app
, cp
, skb
, NULL
);
432 static inline int app_tcp_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
433 struct ip_vs_app
*app
)
436 const unsigned int tcp_offset
= ip_hdrlen(skb
);
440 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
443 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
446 * Remember seq number in case this pkt gets resized
448 seq
= ntohl(th
->seq
);
451 * Fix seq stuff if flagged as so.
453 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
454 vs_fix_seq(&cp
->in_seq
, th
);
455 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
456 vs_fix_ack_seq(&cp
->out_seq
, th
);
459 * Call private input hook function
461 if (app
->pkt_in
== NULL
)
464 if (!app
->pkt_in(app
, cp
, skb
, &diff
))
468 * Update ip_vs seq stuff if len has changed.
471 vs_seq_update(cp
, &cp
->in_seq
,
472 IP_VS_CONN_F_IN_SEQ
, seq
, diff
);
478 * Input pkt hook. Will call bound ip_vs_app specific function
479 * called by ipvs packet handler, assumes previously checked cp!=NULL.
480 * returns false if can't handle packet (oom).
482 int ip_vs_app_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
484 struct ip_vs_app
*app
;
487 * check if application module is bound to
490 if ((app
= cp
->app
) == NULL
)
493 /* TCP is complicated */
494 if (cp
->protocol
== IPPROTO_TCP
)
495 return app_tcp_pkt_in(cp
, skb
, app
);
498 * Call private input hook function
500 if (app
->pkt_in
== NULL
)
503 return app
->pkt_in(app
, cp
, skb
, NULL
);
507 #ifdef CONFIG_PROC_FS
509 * /proc/net/ip_vs_app entry function
512 static struct ip_vs_app
*ip_vs_app_idx(struct netns_ipvs
*ipvs
, loff_t pos
)
514 struct ip_vs_app
*app
, *inc
;
516 list_for_each_entry(app
, &ipvs
->app_list
, a_list
) {
517 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
526 static void *ip_vs_app_seq_start(struct seq_file
*seq
, loff_t
*pos
)
528 struct net
*net
= seq_file_net(seq
);
529 struct netns_ipvs
*ipvs
= net_ipvs(net
);
531 mutex_lock(&__ip_vs_app_mutex
);
533 return *pos
? ip_vs_app_idx(ipvs
, *pos
- 1) : SEQ_START_TOKEN
;
536 static void *ip_vs_app_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
538 struct ip_vs_app
*inc
, *app
;
540 struct net
*net
= seq_file_net(seq
);
541 struct netns_ipvs
*ipvs
= net_ipvs(net
);
544 if (v
== SEQ_START_TOKEN
)
545 return ip_vs_app_idx(ipvs
, 0);
550 if ((e
= inc
->a_list
.next
) != &app
->incs_list
)
551 return list_entry(e
, struct ip_vs_app
, a_list
);
553 /* go on to next application */
554 for (e
= app
->a_list
.next
; e
!= &ipvs
->app_list
; e
= e
->next
) {
555 app
= list_entry(e
, struct ip_vs_app
, a_list
);
556 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
563 static void ip_vs_app_seq_stop(struct seq_file
*seq
, void *v
)
565 mutex_unlock(&__ip_vs_app_mutex
);
568 static int ip_vs_app_seq_show(struct seq_file
*seq
, void *v
)
570 if (v
== SEQ_START_TOKEN
)
571 seq_puts(seq
, "prot port usecnt name\n");
573 const struct ip_vs_app
*inc
= v
;
575 seq_printf(seq
, "%-3s %-7u %-6d %-17s\n",
576 ip_vs_proto_name(inc
->protocol
),
578 atomic_read(&inc
->usecnt
),
584 static const struct seq_operations ip_vs_app_seq_ops
= {
585 .start
= ip_vs_app_seq_start
,
586 .next
= ip_vs_app_seq_next
,
587 .stop
= ip_vs_app_seq_stop
,
588 .show
= ip_vs_app_seq_show
,
591 static int ip_vs_app_open(struct inode
*inode
, struct file
*file
)
593 return seq_open_net(inode
, file
, &ip_vs_app_seq_ops
,
594 sizeof(struct seq_net_private
));
597 static const struct file_operations ip_vs_app_fops
= {
598 .owner
= THIS_MODULE
,
599 .open
= ip_vs_app_open
,
602 .release
= seq_release_net
,
606 int __net_init
ip_vs_app_net_init(struct netns_ipvs
*ipvs
)
608 INIT_LIST_HEAD(&ipvs
->app_list
);
609 proc_create("ip_vs_app", 0, ipvs
->net
->proc_net
, &ip_vs_app_fops
);
613 void __net_exit
ip_vs_app_net_cleanup(struct netns_ipvs
*ipvs
)
615 unregister_ip_vs_app(ipvs
, NULL
/* all */);
616 remove_proc_entry("ip_vs_app", ipvs
->net
->proc_net
);