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 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/skbuff.h>
26 #include <linux/netfilter.h>
27 #include <net/net_namespace.h>
28 #include <net/protocol.h>
30 #include <asm/system.h>
31 #include <linux/stat.h>
32 #include <linux/proc_fs.h>
33 #include <linux/seq_file.h>
34 #include <linux/mutex.h>
36 #include <net/ip_vs.h>
38 EXPORT_SYMBOL(register_ip_vs_app
);
39 EXPORT_SYMBOL(unregister_ip_vs_app
);
40 EXPORT_SYMBOL(register_ip_vs_app_inc
);
42 /* ipvs application list head */
43 static LIST_HEAD(ip_vs_app_list
);
44 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
);
63 * Allocate/initialize app incarnation and register it in proto apps.
66 ip_vs_app_inc_new(struct ip_vs_app
*app
, __u16 proto
, __u16 port
)
68 struct ip_vs_protocol
*pp
;
69 struct ip_vs_app
*inc
;
72 if (!(pp
= ip_vs_proto_get(proto
)))
73 return -EPROTONOSUPPORT
;
75 if (!pp
->unregister_app
)
78 inc
= kmemdup(app
, sizeof(*inc
), GFP_KERNEL
);
81 INIT_LIST_HEAD(&inc
->p_list
);
82 INIT_LIST_HEAD(&inc
->incs_list
);
84 inc
->port
= htons(port
);
85 atomic_set(&inc
->usecnt
, 0);
89 ip_vs_create_timeout_table(app
->timeouts
,
91 if (!inc
->timeout_table
) {
97 ret
= pp
->register_app(inc
);
101 list_add(&inc
->a_list
, &app
->incs_list
);
102 IP_VS_DBG(9, "%s application %s:%u registered\n",
103 pp
->name
, inc
->name
, inc
->port
);
108 kfree(inc
->timeout_table
);
115 * Release app incarnation
118 ip_vs_app_inc_release(struct ip_vs_app
*inc
)
120 struct ip_vs_protocol
*pp
;
122 if (!(pp
= ip_vs_proto_get(inc
->protocol
)))
125 if (pp
->unregister_app
)
126 pp
->unregister_app(inc
);
128 IP_VS_DBG(9, "%s App %s:%u unregistered\n",
129 pp
->name
, inc
->name
, inc
->port
);
131 list_del(&inc
->a_list
);
133 kfree(inc
->timeout_table
);
139 * Get reference to app inc (only called from softirq)
142 int ip_vs_app_inc_get(struct ip_vs_app
*inc
)
146 atomic_inc(&inc
->usecnt
);
147 if (unlikely((result
= ip_vs_app_get(inc
->app
)) != 1))
148 atomic_dec(&inc
->usecnt
);
154 * Put the app inc (only called from timer or net softirq)
156 void ip_vs_app_inc_put(struct ip_vs_app
*inc
)
158 ip_vs_app_put(inc
->app
);
159 atomic_dec(&inc
->usecnt
);
164 * Register an application incarnation in protocol applications
167 register_ip_vs_app_inc(struct ip_vs_app
*app
, __u16 proto
, __u16 port
)
171 mutex_lock(&__ip_vs_app_mutex
);
173 result
= ip_vs_app_inc_new(app
, proto
, port
);
175 mutex_unlock(&__ip_vs_app_mutex
);
182 * ip_vs_app registration routine
184 int register_ip_vs_app(struct ip_vs_app
*app
)
186 /* increase the module use count */
187 ip_vs_use_count_inc();
189 mutex_lock(&__ip_vs_app_mutex
);
191 list_add(&app
->a_list
, &ip_vs_app_list
);
193 mutex_unlock(&__ip_vs_app_mutex
);
200 * ip_vs_app unregistration routine
201 * We are sure there are no app incarnations attached to services
203 void unregister_ip_vs_app(struct ip_vs_app
*app
)
205 struct ip_vs_app
*inc
, *nxt
;
207 mutex_lock(&__ip_vs_app_mutex
);
209 list_for_each_entry_safe(inc
, nxt
, &app
->incs_list
, a_list
) {
210 ip_vs_app_inc_release(inc
);
213 list_del(&app
->a_list
);
215 mutex_unlock(&__ip_vs_app_mutex
);
217 /* decrease the module use count */
218 ip_vs_use_count_dec();
223 * Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
225 int ip_vs_bind_app(struct ip_vs_conn
*cp
, struct ip_vs_protocol
*pp
)
227 return pp
->app_conn_bind(cp
);
232 * Unbind cp from application incarnation (called by cp destructor)
234 void ip_vs_unbind_app(struct ip_vs_conn
*cp
)
236 struct ip_vs_app
*inc
= cp
->app
;
241 if (inc
->unbind_conn
)
242 inc
->unbind_conn(inc
, cp
);
244 inc
->done_conn(inc
, cp
);
245 ip_vs_app_inc_put(inc
);
251 * Fixes th->seq based on ip_vs_seq info.
253 static inline void vs_fix_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
255 __u32 seq
= ntohl(th
->seq
);
258 * Adjust seq with delta-offset for all packets after
259 * the most recent resized pkt seq and with previous_delta offset
260 * for all packets before most recent resized pkt seq.
262 if (vseq
->delta
|| vseq
->previous_delta
) {
263 if(after(seq
, vseq
->init_seq
)) {
264 th
->seq
= htonl(seq
+ vseq
->delta
);
265 IP_VS_DBG(9, "vs_fix_seq(): added delta (%d) to seq\n",
268 th
->seq
= htonl(seq
+ vseq
->previous_delta
);
269 IP_VS_DBG(9, "vs_fix_seq(): added previous_delta "
270 "(%d) to seq\n", vseq
->previous_delta
);
277 * Fixes th->ack_seq based on ip_vs_seq info.
280 vs_fix_ack_seq(const struct ip_vs_seq
*vseq
, struct tcphdr
*th
)
282 __u32 ack_seq
= ntohl(th
->ack_seq
);
285 * Adjust ack_seq with delta-offset for
286 * the packets AFTER most recent resized pkt has caused a shift
287 * for packets before most recent resized pkt, use previous_delta
289 if (vseq
->delta
|| vseq
->previous_delta
) {
290 /* since ack_seq is the number of octet that is expected
291 to receive next, so compare it with init_seq+delta */
292 if(after(ack_seq
, vseq
->init_seq
+vseq
->delta
)) {
293 th
->ack_seq
= htonl(ack_seq
- vseq
->delta
);
294 IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted delta "
295 "(%d) from ack_seq\n", vseq
->delta
);
298 th
->ack_seq
= htonl(ack_seq
- vseq
->previous_delta
);
299 IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted "
300 "previous_delta (%d) from ack_seq\n",
301 vseq
->previous_delta
);
308 * Updates ip_vs_seq if pkt has been resized
309 * Assumes already checked proto==IPPROTO_TCP and diff!=0.
311 static inline void vs_seq_update(struct ip_vs_conn
*cp
, struct ip_vs_seq
*vseq
,
312 unsigned flag
, __u32 seq
, int diff
)
314 /* spinlock is to keep updating cp->flags atomic */
315 spin_lock(&cp
->lock
);
316 if (!(cp
->flags
& flag
) || after(seq
, vseq
->init_seq
)) {
317 vseq
->previous_delta
= vseq
->delta
;
319 vseq
->init_seq
= seq
;
322 spin_unlock(&cp
->lock
);
325 static inline int app_tcp_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
326 struct ip_vs_app
*app
)
329 const unsigned int tcp_offset
= ip_hdrlen(skb
);
333 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
336 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
339 * Remember seq number in case this pkt gets resized
341 seq
= ntohl(th
->seq
);
344 * Fix seq stuff if flagged as so.
346 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
347 vs_fix_seq(&cp
->out_seq
, th
);
348 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
349 vs_fix_ack_seq(&cp
->in_seq
, th
);
352 * Call private output hook function
354 if (app
->pkt_out
== NULL
)
357 if (!app
->pkt_out(app
, cp
, skb
, &diff
))
361 * Update ip_vs seq stuff if len has changed.
364 vs_seq_update(cp
, &cp
->out_seq
,
365 IP_VS_CONN_F_OUT_SEQ
, seq
, diff
);
371 * Output pkt hook. Will call bound ip_vs_app specific function
372 * called by ipvs packet handler, assumes previously checked cp!=NULL
373 * returns false if it can't handle packet (oom)
375 int ip_vs_app_pkt_out(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
377 struct ip_vs_app
*app
;
380 * check if application module is bound to
383 if ((app
= cp
->app
) == NULL
)
386 /* TCP is complicated */
387 if (cp
->protocol
== IPPROTO_TCP
)
388 return app_tcp_pkt_out(cp
, skb
, app
);
391 * Call private output hook function
393 if (app
->pkt_out
== NULL
)
396 return app
->pkt_out(app
, cp
, skb
, NULL
);
400 static inline int app_tcp_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
,
401 struct ip_vs_app
*app
)
404 const unsigned int tcp_offset
= ip_hdrlen(skb
);
408 if (!skb_make_writable(skb
, tcp_offset
+ sizeof(*th
)))
411 th
= (struct tcphdr
*)(skb_network_header(skb
) + tcp_offset
);
414 * Remember seq number in case this pkt gets resized
416 seq
= ntohl(th
->seq
);
419 * Fix seq stuff if flagged as so.
421 if (cp
->flags
& IP_VS_CONN_F_IN_SEQ
)
422 vs_fix_seq(&cp
->in_seq
, th
);
423 if (cp
->flags
& IP_VS_CONN_F_OUT_SEQ
)
424 vs_fix_ack_seq(&cp
->out_seq
, th
);
427 * Call private input hook function
429 if (app
->pkt_in
== NULL
)
432 if (!app
->pkt_in(app
, cp
, skb
, &diff
))
436 * Update ip_vs seq stuff if len has changed.
439 vs_seq_update(cp
, &cp
->in_seq
,
440 IP_VS_CONN_F_IN_SEQ
, seq
, diff
);
446 * Input pkt hook. Will call bound ip_vs_app specific function
447 * called by ipvs packet handler, assumes previously checked cp!=NULL.
448 * returns false if can't handle packet (oom).
450 int ip_vs_app_pkt_in(struct ip_vs_conn
*cp
, struct sk_buff
*skb
)
452 struct ip_vs_app
*app
;
455 * check if application module is bound to
458 if ((app
= cp
->app
) == NULL
)
461 /* TCP is complicated */
462 if (cp
->protocol
== IPPROTO_TCP
)
463 return app_tcp_pkt_in(cp
, skb
, app
);
466 * Call private input hook function
468 if (app
->pkt_in
== NULL
)
471 return app
->pkt_in(app
, cp
, skb
, NULL
);
475 #ifdef CONFIG_PROC_FS
477 * /proc/net/ip_vs_app entry function
480 static struct ip_vs_app
*ip_vs_app_idx(loff_t pos
)
482 struct ip_vs_app
*app
, *inc
;
484 list_for_each_entry(app
, &ip_vs_app_list
, a_list
) {
485 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
494 static void *ip_vs_app_seq_start(struct seq_file
*seq
, loff_t
*pos
)
496 mutex_lock(&__ip_vs_app_mutex
);
498 return *pos
? ip_vs_app_idx(*pos
- 1) : SEQ_START_TOKEN
;
501 static void *ip_vs_app_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
503 struct ip_vs_app
*inc
, *app
;
507 if (v
== SEQ_START_TOKEN
)
508 return ip_vs_app_idx(0);
513 if ((e
= inc
->a_list
.next
) != &app
->incs_list
)
514 return list_entry(e
, struct ip_vs_app
, a_list
);
516 /* go on to next application */
517 for (e
= app
->a_list
.next
; e
!= &ip_vs_app_list
; e
= e
->next
) {
518 app
= list_entry(e
, struct ip_vs_app
, a_list
);
519 list_for_each_entry(inc
, &app
->incs_list
, a_list
) {
526 static void ip_vs_app_seq_stop(struct seq_file
*seq
, void *v
)
528 mutex_unlock(&__ip_vs_app_mutex
);
531 static int ip_vs_app_seq_show(struct seq_file
*seq
, void *v
)
533 if (v
== SEQ_START_TOKEN
)
534 seq_puts(seq
, "prot port usecnt name\n");
536 const struct ip_vs_app
*inc
= v
;
538 seq_printf(seq
, "%-3s %-7u %-6d %-17s\n",
539 ip_vs_proto_name(inc
->protocol
),
541 atomic_read(&inc
->usecnt
),
547 static const struct seq_operations ip_vs_app_seq_ops
= {
548 .start
= ip_vs_app_seq_start
,
549 .next
= ip_vs_app_seq_next
,
550 .stop
= ip_vs_app_seq_stop
,
551 .show
= ip_vs_app_seq_show
,
554 static int ip_vs_app_open(struct inode
*inode
, struct file
*file
)
556 return seq_open(file
, &ip_vs_app_seq_ops
);
559 static const struct file_operations ip_vs_app_fops
= {
560 .owner
= THIS_MODULE
,
561 .open
= ip_vs_app_open
,
564 .release
= seq_release
,
570 * Replace a segment of data with a new segment
572 int ip_vs_skb_replace(struct sk_buff
*skb
, gfp_t pri
,
573 char *o_buf
, int o_len
, char *n_buf
, int n_len
)
581 diff
= n_len
- o_len
;
582 o_offset
= o_buf
- (char *)skb
->data
;
583 /* The length of left data after o_buf+o_len in the skb data */
584 o_left
= skb
->len
- (o_offset
+ o_len
);
587 memmove(o_buf
+ n_len
, o_buf
+ o_len
, o_left
);
588 memcpy(o_buf
, n_buf
, n_len
);
589 skb_trim(skb
, skb
->len
+ diff
);
590 } else if (diff
<= skb_tailroom(skb
)) {
592 memmove(o_buf
+ n_len
, o_buf
+ o_len
, o_left
);
593 memcpy(o_buf
, n_buf
, n_len
);
595 if (pskb_expand_head(skb
, skb_headroom(skb
), diff
, pri
))
598 memmove(skb
->data
+ o_offset
+ n_len
,
599 skb
->data
+ o_offset
+ o_len
, o_left
);
600 skb_copy_to_linear_data_offset(skb
, o_offset
, n_buf
, n_len
);
603 /* must update the iph total length here */
604 ip_hdr(skb
)->tot_len
= htons(skb
->len
);
611 int ip_vs_app_init(void)
613 /* we will replace it with proc_net_ipvs_create() soon */
614 proc_net_fops_create(&init_net
, "ip_vs_app", 0, &ip_vs_app_fops
);
619 void ip_vs_app_cleanup(void)
621 proc_net_remove(&init_net
, "ip_vs_app");