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 <asm/system.h>
35 #include <linux/stat.h>
36 #include <linux/proc_fs.h>
37 #include <linux/seq_file.h>
38 #include <linux/mutex.h>
40 #include <net/ip_vs.h>
42 EXPORT_SYMBOL(register_ip_vs_app
);
43 EXPORT_SYMBOL(unregister_ip_vs_app
);
44 EXPORT_SYMBOL(register_ip_vs_app_inc
);
46 static DEFINE_MUTEX(__ip_vs_app_mutex
);
49 * Get an ip_vs_app object
51 static inline int ip_vs_app_get(struct ip_vs_app
*app
)
53 return try_module_get(app
->module
);
57 static inline void ip_vs_app_put(struct ip_vs_app
*app
)
59 module_put(app
->module
);
64 * Allocate/initialize app incarnation and register it in proto apps.
67 ip_vs_app_inc_new(struct net
*net
, struct ip_vs_app
*app
, __u16 proto
,
70 struct ip_vs_protocol
*pp
;
71 struct ip_vs_app
*inc
;
74 if (!(pp
= ip_vs_proto_get(proto
)))
75 return -EPROTONOSUPPORT
;
77 if (!pp
->unregister_app
)
80 inc
= kmemdup(app
, sizeof(*inc
), GFP_KERNEL
);
83 INIT_LIST_HEAD(&inc
->p_list
);
84 INIT_LIST_HEAD(&inc
->incs_list
);
86 inc
->port
= htons(port
);
87 atomic_set(&inc
->usecnt
, 0);
91 ip_vs_create_timeout_table(app
->timeouts
,
93 if (!inc
->timeout_table
) {
99 ret
= pp
->register_app(net
, inc
);
103 list_add(&inc
->a_list
, &app
->incs_list
);
104 IP_VS_DBG(9, "%s App %s:%u registered\n",
105 pp
->name
, inc
->name
, ntohs(inc
->port
));
110 kfree(inc
->timeout_table
);
117 * Release app incarnation
120 ip_vs_app_inc_release(struct net
*net
, struct ip_vs_app
*inc
)
122 struct ip_vs_protocol
*pp
;
124 if (!(pp
= ip_vs_proto_get(inc
->protocol
)))
127 if (pp
->unregister_app
)
128 pp
->unregister_app(net
, inc
);
130 IP_VS_DBG(9, "%s App %s:%u unregistered\n",
131 pp
->name
, inc
->name
, ntohs(inc
->port
));
133 list_del(&inc
->a_list
);
135 kfree(inc
->timeout_table
);
141 * Get reference to app inc (only called from softirq)
144 int ip_vs_app_inc_get(struct ip_vs_app
*inc
)
148 atomic_inc(&inc
->usecnt
);
149 if (unlikely((result
= ip_vs_app_get(inc
->app
)) != 1))
150 atomic_dec(&inc
->usecnt
);
156 * Put the app inc (only called from timer or net softirq)
158 void ip_vs_app_inc_put(struct ip_vs_app
*inc
)
160 ip_vs_app_put(inc
->app
);
161 atomic_dec(&inc
->usecnt
);
166 * Register an application incarnation in protocol applications
169 register_ip_vs_app_inc(struct net
*net
, struct ip_vs_app
*app
, __u16 proto
,
174 mutex_lock(&__ip_vs_app_mutex
);
176 result
= ip_vs_app_inc_new(net
, app
, proto
, port
);
178 mutex_unlock(&__ip_vs_app_mutex
);
185 * ip_vs_app registration routine
187 int register_ip_vs_app(struct net
*net
, struct ip_vs_app
*app
)
189 struct netns_ipvs
*ipvs
= net_ipvs(net
);
190 /* increase the module use count */
191 ip_vs_use_count_inc();
193 mutex_lock(&__ip_vs_app_mutex
);
195 list_add(&app
->a_list
, &ipvs
->app_list
);
197 mutex_unlock(&__ip_vs_app_mutex
);
204 * ip_vs_app unregistration routine
205 * We are sure there are no app incarnations attached to services
207 void unregister_ip_vs_app(struct net
*net
, struct ip_vs_app
*app
)
209 struct ip_vs_app
*inc
, *nxt
;
211 mutex_lock(&__ip_vs_app_mutex
);
213 list_for_each_entry_safe(inc
, nxt
, &app
->incs_list
, a_list
) {
214 ip_vs_app_inc_release(net
, inc
);
217 list_del(&app
->a_list
);
219 mutex_unlock(&__ip_vs_app_mutex
);
221 /* decrease the module use count */
222 ip_vs_use_count_dec();
227 * Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
229 int ip_vs_bind_app(struct ip_vs_conn
*cp
,
230 struct ip_vs_protocol
*pp
)
232 return pp
->app_conn_bind(cp
);
237 * Unbind cp from application incarnation (called by cp destructor)
239 void ip_vs_unbind_app(struct ip_vs_conn
*cp
)
241 struct ip_vs_app
*inc
= cp
->app
;
246 if (inc
->unbind_conn
)
247 inc
->unbind_conn(inc
, cp
);
249 inc
->done_conn(inc
, cp
);
250 ip_vs_app_inc_put(inc
);
256 * Fixes th->seq based on ip_vs_seq info.
258 static inline void vs_fix_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
260 __u32 seq
= ntohl(th
->seq
);
263 * Adjust seq with delta-offset for all packets after
264 * the most recent resized pkt seq and with previous_delta offset
265 * for all packets before most recent resized pkt seq.
267 if (vseq
->delta
|| vseq
->previous_delta
) {
268 if(after(seq
, vseq
->init_seq
)) {
269 th
->seq
= htonl(seq
+ vseq
->delta
);
270 IP_VS_DBG(9, "%s(): added delta (%d) to seq\n",
271 __func__
, vseq
->delta
);
273 th
->seq
= htonl(seq
+ vseq
->previous_delta
);
274 IP_VS_DBG(9, "%s(): added previous_delta (%d) to seq\n",
275 __func__
, vseq
->previous_delta
);
282 * Fixes th->ack_seq based on ip_vs_seq info.
285 vs_fix_ack_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
287 __u32 ack_seq
= ntohl(th
->ack_seq
);
290 * Adjust ack_seq with delta-offset for
291 * the packets AFTER most recent resized pkt has caused a shift
292 * for packets before most recent resized pkt, use previous_delta
294 if (vseq
->delta
|| vseq
->previous_delta
) {
295 /* since ack_seq is the number of octet that is expected
296 to receive next, so compare it with init_seq+delta */
297 if(after(ack_seq
, vseq
->init_seq
+vseq
->delta
)) {
298 th
->ack_seq
= htonl(ack_seq
- vseq
->delta
);
299 IP_VS_DBG(9, "%s(): subtracted delta "
300 "(%d) from ack_seq\n", __func__
, vseq
->delta
);
303 th
->ack_seq
= htonl(ack_seq
- vseq
->previous_delta
);
304 IP_VS_DBG(9, "%s(): subtracted "
305 "previous_delta (%d) from ack_seq\n",
306 __func__
, vseq
->previous_delta
);
313 * Updates ip_vs_seq if pkt has been resized
314 * Assumes already checked proto==IPPROTO_TCP and diff!=0.
316 static inline void vs_seq_update(struct ip_vs_conn
*cp
, struct ip_vs_seq
*vseq
,
317 unsigned flag
, __u32 seq
, int diff
)
319 /* spinlock is to keep updating cp->flags atomic */
320 spin_lock(&cp
->lock
);
321 if (!(cp
->flags
& flag
) || after(seq
, vseq
->init_seq
)) {
322 vseq
->previous_delta
= vseq
->delta
;
324 vseq
->init_seq
= seq
;
327 spin_unlock(&cp
->lock
);
330 static inline int app_tcp_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
331 struct ip_vs_app
*app
)
334 const unsigned int tcp_offset
= ip_hdrlen(skb
);
338 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
341 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
344 * Remember seq number in case this pkt gets resized
346 seq
= ntohl(th
->seq
);
349 * Fix seq stuff if flagged as so.
351 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
352 vs_fix_seq(&cp
->out_seq
, th
);
353 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
354 vs_fix_ack_seq(&cp
->in_seq
, th
);
357 * Call private output hook function
359 if (app
->pkt_out
== NULL
)
362 if (!app
->pkt_out(app
, cp
, skb
, &diff
))
366 * Update ip_vs seq stuff if len has changed.
369 vs_seq_update(cp
, &cp
->out_seq
,
370 IP_VS_CONN_F_OUT_SEQ
, seq
, diff
);
376 * Output pkt hook. Will call bound ip_vs_app specific function
377 * called by ipvs packet handler, assumes previously checked cp!=NULL
378 * returns false if it can't handle packet (oom)
380 int ip_vs_app_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
382 struct ip_vs_app
*app
;
385 * check if application module is bound to
388 if ((app
= cp
->app
) == NULL
)
391 /* TCP is complicated */
392 if (cp
->protocol
== IPPROTO_TCP
)
393 return app_tcp_pkt_out(cp
, skb
, app
);
396 * Call private output hook function
398 if (app
->pkt_out
== NULL
)
401 return app
->pkt_out(app
, cp
, skb
, NULL
);
405 static inline int app_tcp_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
406 struct ip_vs_app
*app
)
409 const unsigned int tcp_offset
= ip_hdrlen(skb
);
413 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
416 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
419 * Remember seq number in case this pkt gets resized
421 seq
= ntohl(th
->seq
);
424 * Fix seq stuff if flagged as so.
426 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
427 vs_fix_seq(&cp
->in_seq
, th
);
428 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
429 vs_fix_ack_seq(&cp
->out_seq
, th
);
432 * Call private input hook function
434 if (app
->pkt_in
== NULL
)
437 if (!app
->pkt_in(app
, cp
, skb
, &diff
))
441 * Update ip_vs seq stuff if len has changed.
444 vs_seq_update(cp
, &cp
->in_seq
,
445 IP_VS_CONN_F_IN_SEQ
, seq
, diff
);
451 * Input pkt hook. Will call bound ip_vs_app specific function
452 * called by ipvs packet handler, assumes previously checked cp!=NULL.
453 * returns false if can't handle packet (oom).
455 int ip_vs_app_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
457 struct ip_vs_app
*app
;
460 * check if application module is bound to
463 if ((app
= cp
->app
) == NULL
)
466 /* TCP is complicated */
467 if (cp
->protocol
== IPPROTO_TCP
)
468 return app_tcp_pkt_in(cp
, skb
, app
);
471 * Call private input hook function
473 if (app
->pkt_in
== NULL
)
476 return app
->pkt_in(app
, cp
, skb
, NULL
);
480 #ifdef CONFIG_PROC_FS
482 * /proc/net/ip_vs_app entry function
485 static struct ip_vs_app
*ip_vs_app_idx(struct netns_ipvs
*ipvs
, loff_t pos
)
487 struct ip_vs_app
*app
, *inc
;
489 list_for_each_entry(app
, &ipvs
->app_list
, a_list
) {
490 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
499 static void *ip_vs_app_seq_start(struct seq_file
*seq
, loff_t
*pos
)
501 struct net
*net
= seq_file_net(seq
);
502 struct netns_ipvs
*ipvs
= net_ipvs(net
);
504 mutex_lock(&__ip_vs_app_mutex
);
506 return *pos
? ip_vs_app_idx(ipvs
, *pos
- 1) : SEQ_START_TOKEN
;
509 static void *ip_vs_app_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
511 struct ip_vs_app
*inc
, *app
;
513 struct net
*net
= seq_file_net(seq
);
514 struct netns_ipvs
*ipvs
= net_ipvs(net
);
517 if (v
== SEQ_START_TOKEN
)
518 return ip_vs_app_idx(ipvs
, 0);
523 if ((e
= inc
->a_list
.next
) != &app
->incs_list
)
524 return list_entry(e
, struct ip_vs_app
, a_list
);
526 /* go on to next application */
527 for (e
= app
->a_list
.next
; e
!= &ipvs
->app_list
; e
= e
->next
) {
528 app
= list_entry(e
, struct ip_vs_app
, a_list
);
529 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
536 static void ip_vs_app_seq_stop(struct seq_file
*seq
, void *v
)
538 mutex_unlock(&__ip_vs_app_mutex
);
541 static int ip_vs_app_seq_show(struct seq_file
*seq
, void *v
)
543 if (v
== SEQ_START_TOKEN
)
544 seq_puts(seq
, "prot port usecnt name\n");
546 const struct ip_vs_app
*inc
= v
;
548 seq_printf(seq
, "%-3s %-7u %-6d %-17s\n",
549 ip_vs_proto_name(inc
->protocol
),
551 atomic_read(&inc
->usecnt
),
557 static const struct seq_operations ip_vs_app_seq_ops
= {
558 .start
= ip_vs_app_seq_start
,
559 .next
= ip_vs_app_seq_next
,
560 .stop
= ip_vs_app_seq_stop
,
561 .show
= ip_vs_app_seq_show
,
564 static int ip_vs_app_open(struct inode
*inode
, struct file
*file
)
566 return seq_open_net(inode
, file
, &ip_vs_app_seq_ops
,
567 sizeof(struct seq_net_private
));
570 static const struct file_operations ip_vs_app_fops
= {
571 .owner
= THIS_MODULE
,
572 .open
= ip_vs_app_open
,
575 .release
= seq_release_net
,
579 int __net_init
ip_vs_app_net_init(struct net
*net
)
581 struct netns_ipvs
*ipvs
= net_ipvs(net
);
583 INIT_LIST_HEAD(&ipvs
->app_list
);
584 proc_net_fops_create(net
, "ip_vs_app", 0, &ip_vs_app_fops
);
588 void __net_exit
ip_vs_app_net_cleanup(struct net
*net
)
590 proc_net_remove(net
, "ip_vs_app");