linux/net/ipv4/ipvs/ip_vs_app.c
Arjan van de Ven 9a32144e9d [PATCH] mark struct file_operations const 7
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00

630 lines
13 KiB
C

/*
* ip_vs_app.c: Application module support for IPVS
*
* Version: $Id: ip_vs_app.c,v 1.17 2003/03/22 06:31:21 wensong Exp $
*
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Most code here is taken from ip_masq_app.c in kernel 2.2. The difference
* is that ip_vs_app module handles the reverse direction (incoming requests
* and outgoing responses).
*
* IP_MASQ_APP application masquerading module
*
* Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar>
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <asm/system.h>
#include <linux/stat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>
#include <net/ip_vs.h>
EXPORT_SYMBOL(register_ip_vs_app);
EXPORT_SYMBOL(unregister_ip_vs_app);
EXPORT_SYMBOL(register_ip_vs_app_inc);
/* ipvs application list head */
static LIST_HEAD(ip_vs_app_list);
static DEFINE_MUTEX(__ip_vs_app_mutex);
/*
* Get an ip_vs_app object
*/
static inline int ip_vs_app_get(struct ip_vs_app *app)
{
/* test and get the module atomically */
if (app->module)
return try_module_get(app->module);
else
return 1;
}
static inline void ip_vs_app_put(struct ip_vs_app *app)
{
if (app->module)
module_put(app->module);
}
/*
* Allocate/initialize app incarnation and register it in proto apps.
*/
static int
ip_vs_app_inc_new(struct ip_vs_app *app, __u16 proto, __u16 port)
{
struct ip_vs_protocol *pp;
struct ip_vs_app *inc;
int ret;
if (!(pp = ip_vs_proto_get(proto)))
return -EPROTONOSUPPORT;
if (!pp->unregister_app)
return -EOPNOTSUPP;
inc = kmemdup(app, sizeof(*inc), GFP_KERNEL);
if (!inc)
return -ENOMEM;
INIT_LIST_HEAD(&inc->p_list);
INIT_LIST_HEAD(&inc->incs_list);
inc->app = app;
inc->port = htons(port);
atomic_set(&inc->usecnt, 0);
if (app->timeouts) {
inc->timeout_table =
ip_vs_create_timeout_table(app->timeouts,
app->timeouts_size);
if (!inc->timeout_table) {
ret = -ENOMEM;
goto out;
}
}
ret = pp->register_app(inc);
if (ret)
goto out;
list_add(&inc->a_list, &app->incs_list);
IP_VS_DBG(9, "%s application %s:%u registered\n",
pp->name, inc->name, inc->port);
return 0;
out:
kfree(inc->timeout_table);
kfree(inc);
return ret;
}
/*
* Release app incarnation
*/
static void
ip_vs_app_inc_release(struct ip_vs_app *inc)
{
struct ip_vs_protocol *pp;
if (!(pp = ip_vs_proto_get(inc->protocol)))
return;
if (pp->unregister_app)
pp->unregister_app(inc);
IP_VS_DBG(9, "%s App %s:%u unregistered\n",
pp->name, inc->name, inc->port);
list_del(&inc->a_list);
kfree(inc->timeout_table);
kfree(inc);
}
/*
* Get reference to app inc (only called from softirq)
*
*/
int ip_vs_app_inc_get(struct ip_vs_app *inc)
{
int result;
atomic_inc(&inc->usecnt);
if (unlikely((result = ip_vs_app_get(inc->app)) != 1))
atomic_dec(&inc->usecnt);
return result;
}
/*
* Put the app inc (only called from timer or net softirq)
*/
void ip_vs_app_inc_put(struct ip_vs_app *inc)
{
ip_vs_app_put(inc->app);
atomic_dec(&inc->usecnt);
}
/*
* Register an application incarnation in protocol applications
*/
int
register_ip_vs_app_inc(struct ip_vs_app *app, __u16 proto, __u16 port)
{
int result;
mutex_lock(&__ip_vs_app_mutex);
result = ip_vs_app_inc_new(app, proto, port);
mutex_unlock(&__ip_vs_app_mutex);
return result;
}
/*
* ip_vs_app registration routine
*/
int register_ip_vs_app(struct ip_vs_app *app)
{
/* increase the module use count */
ip_vs_use_count_inc();
mutex_lock(&__ip_vs_app_mutex);
list_add(&app->a_list, &ip_vs_app_list);
mutex_unlock(&__ip_vs_app_mutex);
return 0;
}
/*
* ip_vs_app unregistration routine
* We are sure there are no app incarnations attached to services
*/
void unregister_ip_vs_app(struct ip_vs_app *app)
{
struct ip_vs_app *inc, *nxt;
mutex_lock(&__ip_vs_app_mutex);
list_for_each_entry_safe(inc, nxt, &app->incs_list, a_list) {
ip_vs_app_inc_release(inc);
}
list_del(&app->a_list);
mutex_unlock(&__ip_vs_app_mutex);
/* decrease the module use count */
ip_vs_use_count_dec();
}
/*
* Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
*/
int ip_vs_bind_app(struct ip_vs_conn *cp, struct ip_vs_protocol *pp)
{
return pp->app_conn_bind(cp);
}
/*
* Unbind cp from application incarnation (called by cp destructor)
*/
void ip_vs_unbind_app(struct ip_vs_conn *cp)
{
struct ip_vs_app *inc = cp->app;
if (!inc)
return;
if (inc->unbind_conn)
inc->unbind_conn(inc, cp);
if (inc->done_conn)
inc->done_conn(inc, cp);
ip_vs_app_inc_put(inc);
cp->app = NULL;
}
/*
* Fixes th->seq based on ip_vs_seq info.
*/
static inline void vs_fix_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
{
__u32 seq = ntohl(th->seq);
/*
* Adjust seq with delta-offset for all packets after
* the most recent resized pkt seq and with previous_delta offset
* for all packets before most recent resized pkt seq.
*/
if (vseq->delta || vseq->previous_delta) {
if(after(seq, vseq->init_seq)) {
th->seq = htonl(seq + vseq->delta);
IP_VS_DBG(9, "vs_fix_seq(): added delta (%d) to seq\n",
vseq->delta);
} else {
th->seq = htonl(seq + vseq->previous_delta);
IP_VS_DBG(9, "vs_fix_seq(): added previous_delta "
"(%d) to seq\n", vseq->previous_delta);
}
}
}
/*
* Fixes th->ack_seq based on ip_vs_seq info.
*/
static inline void
vs_fix_ack_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
{
__u32 ack_seq = ntohl(th->ack_seq);
/*
* Adjust ack_seq with delta-offset for
* the packets AFTER most recent resized pkt has caused a shift
* for packets before most recent resized pkt, use previous_delta
*/
if (vseq->delta || vseq->previous_delta) {
/* since ack_seq is the number of octet that is expected
to receive next, so compare it with init_seq+delta */
if(after(ack_seq, vseq->init_seq+vseq->delta)) {
th->ack_seq = htonl(ack_seq - vseq->delta);
IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted delta "
"(%d) from ack_seq\n", vseq->delta);
} else {
th->ack_seq = htonl(ack_seq - vseq->previous_delta);
IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted "
"previous_delta (%d) from ack_seq\n",
vseq->previous_delta);
}
}
}
/*
* Updates ip_vs_seq if pkt has been resized
* Assumes already checked proto==IPPROTO_TCP and diff!=0.
*/
static inline void vs_seq_update(struct ip_vs_conn *cp, struct ip_vs_seq *vseq,
unsigned flag, __u32 seq, int diff)
{
/* spinlock is to keep updating cp->flags atomic */
spin_lock(&cp->lock);
if (!(cp->flags & flag) || after(seq, vseq->init_seq)) {
vseq->previous_delta = vseq->delta;
vseq->delta += diff;
vseq->init_seq = seq;
cp->flags |= flag;
}
spin_unlock(&cp->lock);
}
static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb,
struct ip_vs_app *app)
{
int diff;
unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4;
struct tcphdr *th;
__u32 seq;
if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
return 0;
th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset);
/*
* Remember seq number in case this pkt gets resized
*/
seq = ntohl(th->seq);
/*
* Fix seq stuff if flagged as so.
*/
if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
vs_fix_seq(&cp->out_seq, th);
if (cp->flags & IP_VS_CONN_F_IN_SEQ)
vs_fix_ack_seq(&cp->in_seq, th);
/*
* Call private output hook function
*/
if (app->pkt_out == NULL)
return 1;
if (!app->pkt_out(app, cp, pskb, &diff))
return 0;
/*
* Update ip_vs seq stuff if len has changed.
*/
if (diff != 0)
vs_seq_update(cp, &cp->out_seq,
IP_VS_CONN_F_OUT_SEQ, seq, diff);
return 1;
}
/*
* Output pkt hook. Will call bound ip_vs_app specific function
* called by ipvs packet handler, assumes previously checked cp!=NULL
* returns false if it can't handle packet (oom)
*/
int ip_vs_app_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb)
{
struct ip_vs_app *app;
/*
* check if application module is bound to
* this ip_vs_conn.
*/
if ((app = cp->app) == NULL)
return 1;
/* TCP is complicated */
if (cp->protocol == IPPROTO_TCP)
return app_tcp_pkt_out(cp, pskb, app);
/*
* Call private output hook function
*/
if (app->pkt_out == NULL)
return 1;
return app->pkt_out(app, cp, pskb, NULL);
}
static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb,
struct ip_vs_app *app)
{
int diff;
unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4;
struct tcphdr *th;
__u32 seq;
if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
return 0;
th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset);
/*
* Remember seq number in case this pkt gets resized
*/
seq = ntohl(th->seq);
/*
* Fix seq stuff if flagged as so.
*/
if (cp->flags & IP_VS_CONN_F_IN_SEQ)
vs_fix_seq(&cp->in_seq, th);
if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
vs_fix_ack_seq(&cp->out_seq, th);
/*
* Call private input hook function
*/
if (app->pkt_in == NULL)
return 1;
if (!app->pkt_in(app, cp, pskb, &diff))
return 0;
/*
* Update ip_vs seq stuff if len has changed.
*/
if (diff != 0)
vs_seq_update(cp, &cp->in_seq,
IP_VS_CONN_F_IN_SEQ, seq, diff);
return 1;
}
/*
* Input pkt hook. Will call bound ip_vs_app specific function
* called by ipvs packet handler, assumes previously checked cp!=NULL.
* returns false if can't handle packet (oom).
*/
int ip_vs_app_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb)
{
struct ip_vs_app *app;
/*
* check if application module is bound to
* this ip_vs_conn.
*/
if ((app = cp->app) == NULL)
return 1;
/* TCP is complicated */
if (cp->protocol == IPPROTO_TCP)
return app_tcp_pkt_in(cp, pskb, app);
/*
* Call private input hook function
*/
if (app->pkt_in == NULL)
return 1;
return app->pkt_in(app, cp, pskb, NULL);
}
#ifdef CONFIG_PROC_FS
/*
* /proc/net/ip_vs_app entry function
*/
static struct ip_vs_app *ip_vs_app_idx(loff_t pos)
{
struct ip_vs_app *app, *inc;
list_for_each_entry(app, &ip_vs_app_list, a_list) {
list_for_each_entry(inc, &app->incs_list, a_list) {
if (pos-- == 0)
return inc;
}
}
return NULL;
}
static void *ip_vs_app_seq_start(struct seq_file *seq, loff_t *pos)
{
mutex_lock(&__ip_vs_app_mutex);
return *pos ? ip_vs_app_idx(*pos - 1) : SEQ_START_TOKEN;
}
static void *ip_vs_app_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct ip_vs_app *inc, *app;
struct list_head *e;
++*pos;
if (v == SEQ_START_TOKEN)
return ip_vs_app_idx(0);
inc = v;
app = inc->app;
if ((e = inc->a_list.next) != &app->incs_list)
return list_entry(e, struct ip_vs_app, a_list);
/* go on to next application */
for (e = app->a_list.next; e != &ip_vs_app_list; e = e->next) {
app = list_entry(e, struct ip_vs_app, a_list);
list_for_each_entry(inc, &app->incs_list, a_list) {
return inc;
}
}
return NULL;
}
static void ip_vs_app_seq_stop(struct seq_file *seq, void *v)
{
mutex_unlock(&__ip_vs_app_mutex);
}
static int ip_vs_app_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_puts(seq, "prot port usecnt name\n");
else {
const struct ip_vs_app *inc = v;
seq_printf(seq, "%-3s %-7u %-6d %-17s\n",
ip_vs_proto_name(inc->protocol),
ntohs(inc->port),
atomic_read(&inc->usecnt),
inc->name);
}
return 0;
}
static struct seq_operations ip_vs_app_seq_ops = {
.start = ip_vs_app_seq_start,
.next = ip_vs_app_seq_next,
.stop = ip_vs_app_seq_stop,
.show = ip_vs_app_seq_show,
};
static int ip_vs_app_open(struct inode *inode, struct file *file)
{
return seq_open(file, &ip_vs_app_seq_ops);
}
static const struct file_operations ip_vs_app_fops = {
.owner = THIS_MODULE,
.open = ip_vs_app_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif
/*
* Replace a segment of data with a new segment
*/
int ip_vs_skb_replace(struct sk_buff *skb, gfp_t pri,
char *o_buf, int o_len, char *n_buf, int n_len)
{
struct iphdr *iph;
int diff;
int o_offset;
int o_left;
EnterFunction(9);
diff = n_len - o_len;
o_offset = o_buf - (char *)skb->data;
/* The length of left data after o_buf+o_len in the skb data */
o_left = skb->len - (o_offset + o_len);
if (diff <= 0) {
memmove(o_buf + n_len, o_buf + o_len, o_left);
memcpy(o_buf, n_buf, n_len);
skb_trim(skb, skb->len + diff);
} else if (diff <= skb_tailroom(skb)) {
skb_put(skb, diff);
memmove(o_buf + n_len, o_buf + o_len, o_left);
memcpy(o_buf, n_buf, n_len);
} else {
if (pskb_expand_head(skb, skb_headroom(skb), diff, pri))
return -ENOMEM;
skb_put(skb, diff);
memmove(skb->data + o_offset + n_len,
skb->data + o_offset + o_len, o_left);
memcpy(skb->data + o_offset, n_buf, n_len);
}
/* must update the iph total length here */
iph = skb->nh.iph;
iph->tot_len = htons(skb->len);
LeaveFunction(9);
return 0;
}
int ip_vs_app_init(void)
{
/* we will replace it with proc_net_ipvs_create() soon */
proc_net_fops_create("ip_vs_app", 0, &ip_vs_app_fops);
return 0;
}
void ip_vs_app_cleanup(void)
{
proc_net_remove("ip_vs_app");
}