mirror of
https://github.com/joel16/android_kernel_sony_msm8994.git
synced 2024-12-13 23:50:57 +00:00
[NETFILTER]: nf_conntrack/nf_nat: add SIP helper port
Add IPv4 and IPv6 capable nf_conntrack port of the SIP conntrack/NAT helper. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy
David S. Miller
parent
f09943fefe
commit
9fafcd7b20
41
include/linux/netfilter/nf_conntrack_sip.h
Normal file
41
include/linux/netfilter/nf_conntrack_sip.h
Normal file
@ -0,0 +1,41 @@
|
||||
#ifndef __NF_CONNTRACK_SIP_H__
|
||||
#define __NF_CONNTRACK_SIP_H__
|
||||
#ifdef __KERNEL__
|
||||
|
||||
#define SIP_PORT 5060
|
||||
#define SIP_TIMEOUT 3600
|
||||
|
||||
enum sip_header_pos {
|
||||
POS_REG_REQ_URI,
|
||||
POS_REQ_URI,
|
||||
POS_FROM,
|
||||
POS_TO,
|
||||
POS_VIA,
|
||||
POS_CONTACT,
|
||||
POS_CONTENT,
|
||||
POS_MEDIA,
|
||||
POS_OWNER_IP4,
|
||||
POS_CONNECTION_IP4,
|
||||
POS_OWNER_IP6,
|
||||
POS_CONNECTION_IP6,
|
||||
POS_SDP_HEADER,
|
||||
};
|
||||
|
||||
extern unsigned int (*nf_nat_sip_hook)(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
const char **dptr);
|
||||
extern unsigned int (*nf_nat_sdp_hook)(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conntrack_expect *exp,
|
||||
const char *dptr);
|
||||
|
||||
extern int ct_sip_get_info(struct nf_conn *ct, const char *dptr, size_t dlen,
|
||||
unsigned int *matchoff, unsigned int *matchlen,
|
||||
enum sip_header_pos pos);
|
||||
extern int ct_sip_lnlen(const char *line, const char *limit);
|
||||
extern const char *ct_sip_search(const char *needle, const char *haystack,
|
||||
size_t needle_len, size_t haystack_len,
|
||||
int case_sensitive);
|
||||
#endif /* __KERNEL__ */
|
||||
#endif /* __NF_CONNTRACK_SIP_H__ */
|
||||
@ -555,6 +555,11 @@ config IP_NF_NAT_SIP
|
||||
default IP_NF_NAT if IP_NF_SIP=y
|
||||
default m if IP_NF_SIP=m
|
||||
|
||||
config NF_NAT_SIP
|
||||
tristate
|
||||
depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
|
||||
default NF_NAT && NF_CONNTRACK_SIP
|
||||
|
||||
# mangle + specific targets
|
||||
config IP_NF_MANGLE
|
||||
tristate "Packet mangling"
|
||||
|
||||
@ -55,6 +55,7 @@ obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
|
||||
obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
|
||||
obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
|
||||
obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
|
||||
obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
|
||||
|
||||
# NAT protocols (nf_nat)
|
||||
obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
|
||||
|
||||
283
net/ipv4/netfilter/nf_nat_sip.c
Normal file
283
net/ipv4/netfilter/nf_nat_sip.c
Normal file
@ -0,0 +1,283 @@
|
||||
/* SIP extension for UDP NAT alteration.
|
||||
*
|
||||
* (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
|
||||
* based on RR's ip_nat_ftp.c and other modules.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/skbuff.h>
|
||||
#include <linux/ip.h>
|
||||
#include <linux/udp.h>
|
||||
|
||||
#include <net/netfilter/nf_nat.h>
|
||||
#include <net/netfilter/nf_nat_helper.h>
|
||||
#include <net/netfilter/nf_nat_rule.h>
|
||||
#include <net/netfilter/nf_conntrack_helper.h>
|
||||
#include <net/netfilter/nf_conntrack_expect.h>
|
||||
#include <linux/netfilter/nf_conntrack_sip.h>
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>");
|
||||
MODULE_DESCRIPTION("SIP NAT helper");
|
||||
MODULE_ALIAS("ip_nat_sip");
|
||||
|
||||
#if 0
|
||||
#define DEBUGP printk
|
||||
#else
|
||||
#define DEBUGP(format, args...)
|
||||
#endif
|
||||
|
||||
struct addr_map {
|
||||
struct {
|
||||
char src[sizeof("nnn.nnn.nnn.nnn:nnnnn")];
|
||||
char dst[sizeof("nnn.nnn.nnn.nnn:nnnnn")];
|
||||
unsigned int srclen, srciplen;
|
||||
unsigned int dstlen, dstiplen;
|
||||
} addr[IP_CT_DIR_MAX];
|
||||
};
|
||||
|
||||
static void addr_map_init(struct nf_conn *ct, struct addr_map *map)
|
||||
{
|
||||
struct nf_conntrack_tuple *t;
|
||||
enum ip_conntrack_dir dir;
|
||||
unsigned int n;
|
||||
|
||||
for (dir = 0; dir < IP_CT_DIR_MAX; dir++) {
|
||||
t = &ct->tuplehash[dir].tuple;
|
||||
|
||||
n = sprintf(map->addr[dir].src, "%u.%u.%u.%u",
|
||||
NIPQUAD(t->src.u3.ip));
|
||||
map->addr[dir].srciplen = n;
|
||||
n += sprintf(map->addr[dir].src + n, ":%u",
|
||||
ntohs(t->src.u.udp.port));
|
||||
map->addr[dir].srclen = n;
|
||||
|
||||
n = sprintf(map->addr[dir].dst, "%u.%u.%u.%u",
|
||||
NIPQUAD(t->dst.u3.ip));
|
||||
map->addr[dir].dstiplen = n;
|
||||
n += sprintf(map->addr[dir].dst + n, ":%u",
|
||||
ntohs(t->dst.u.udp.port));
|
||||
map->addr[dir].dstlen = n;
|
||||
}
|
||||
}
|
||||
|
||||
static int map_sip_addr(struct sk_buff **pskb, enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct, const char **dptr, size_t dlen,
|
||||
enum sip_header_pos pos, struct addr_map *map)
|
||||
{
|
||||
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
|
||||
unsigned int matchlen, matchoff, addrlen;
|
||||
char *addr;
|
||||
|
||||
if (ct_sip_get_info(ct, *dptr, dlen, &matchoff, &matchlen, pos) <= 0)
|
||||
return 1;
|
||||
|
||||
if ((matchlen == map->addr[dir].srciplen ||
|
||||
matchlen == map->addr[dir].srclen) &&
|
||||
memcmp(*dptr + matchoff, map->addr[dir].src, matchlen) == 0) {
|
||||
addr = map->addr[!dir].dst;
|
||||
addrlen = map->addr[!dir].dstlen;
|
||||
} else if ((matchlen == map->addr[dir].dstiplen ||
|
||||
matchlen == map->addr[dir].dstlen) &&
|
||||
memcmp(*dptr + matchoff, map->addr[dir].dst, matchlen) == 0) {
|
||||
addr = map->addr[!dir].src;
|
||||
addrlen = map->addr[!dir].srclen;
|
||||
} else
|
||||
return 1;
|
||||
|
||||
if (!nf_nat_mangle_udp_packet(pskb, ct, ctinfo,
|
||||
matchoff, matchlen, addr, addrlen))
|
||||
return 0;
|
||||
*dptr = (*pskb)->data + (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
|
||||
return 1;
|
||||
|
||||
}
|
||||
|
||||
static unsigned int ip_nat_sip(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
const char **dptr)
|
||||
{
|
||||
enum sip_header_pos pos;
|
||||
struct addr_map map;
|
||||
int dataoff, datalen;
|
||||
|
||||
dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
|
||||
datalen = (*pskb)->len - dataoff;
|
||||
if (datalen < sizeof("SIP/2.0") - 1)
|
||||
return NF_DROP;
|
||||
|
||||
addr_map_init(ct, &map);
|
||||
|
||||
/* Basic rules: requests and responses. */
|
||||
if (strncmp(*dptr, "SIP/2.0", sizeof("SIP/2.0") - 1) != 0) {
|
||||
/* 10.2: Constructing the REGISTER Request:
|
||||
*
|
||||
* The "userinfo" and "@" components of the SIP URI MUST NOT
|
||||
* be present.
|
||||
*/
|
||||
if (datalen >= sizeof("REGISTER") - 1 &&
|
||||
strncmp(*dptr, "REGISTER", sizeof("REGISTER") - 1) == 0)
|
||||
pos = POS_REG_REQ_URI;
|
||||
else
|
||||
pos = POS_REQ_URI;
|
||||
|
||||
if (!map_sip_addr(pskb, ctinfo, ct, dptr, datalen, pos, &map))
|
||||
return NF_DROP;
|
||||
}
|
||||
|
||||
if (!map_sip_addr(pskb, ctinfo, ct, dptr, datalen, POS_FROM, &map) ||
|
||||
!map_sip_addr(pskb, ctinfo, ct, dptr, datalen, POS_TO, &map) ||
|
||||
!map_sip_addr(pskb, ctinfo, ct, dptr, datalen, POS_VIA, &map) ||
|
||||
!map_sip_addr(pskb, ctinfo, ct, dptr, datalen, POS_CONTACT, &map))
|
||||
return NF_DROP;
|
||||
return NF_ACCEPT;
|
||||
}
|
||||
|
||||
static unsigned int mangle_sip_packet(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
const char **dptr, size_t dlen,
|
||||
char *buffer, int bufflen,
|
||||
enum sip_header_pos pos)
|
||||
{
|
||||
unsigned int matchlen, matchoff;
|
||||
|
||||
if (ct_sip_get_info(ct, *dptr, dlen, &matchoff, &matchlen, pos) <= 0)
|
||||
return 0;
|
||||
|
||||
if (!nf_nat_mangle_udp_packet(pskb, ct, ctinfo,
|
||||
matchoff, matchlen, buffer, bufflen))
|
||||
return 0;
|
||||
|
||||
/* We need to reload this. Thanks Patrick. */
|
||||
*dptr = (*pskb)->data + (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
|
||||
return 1;
|
||||
}
|
||||
|
||||
static int mangle_content_len(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
const char *dptr)
|
||||
{
|
||||
unsigned int dataoff, matchoff, matchlen;
|
||||
char buffer[sizeof("65536")];
|
||||
int bufflen;
|
||||
|
||||
dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
|
||||
|
||||
/* Get actual SDP lenght */
|
||||
if (ct_sip_get_info(ct, dptr, (*pskb)->len - dataoff, &matchoff,
|
||||
&matchlen, POS_SDP_HEADER) > 0) {
|
||||
|
||||
/* since ct_sip_get_info() give us a pointer passing 'v='
|
||||
we need to add 2 bytes in this count. */
|
||||
int c_len = (*pskb)->len - dataoff - matchoff + 2;
|
||||
|
||||
/* Now, update SDP length */
|
||||
if (ct_sip_get_info(ct, dptr, (*pskb)->len - dataoff, &matchoff,
|
||||
&matchlen, POS_CONTENT) > 0) {
|
||||
|
||||
bufflen = sprintf(buffer, "%u", c_len);
|
||||
return nf_nat_mangle_udp_packet(pskb, ct, ctinfo,
|
||||
matchoff, matchlen,
|
||||
buffer, bufflen);
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static unsigned int mangle_sdp(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
__be32 newip, u_int16_t port,
|
||||
const char *dptr)
|
||||
{
|
||||
char buffer[sizeof("nnn.nnn.nnn.nnn")];
|
||||
unsigned int dataoff, bufflen;
|
||||
|
||||
dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
|
||||
|
||||
/* Mangle owner and contact info. */
|
||||
bufflen = sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(newip));
|
||||
if (!mangle_sip_packet(pskb, ctinfo, ct, &dptr, (*pskb)->len - dataoff,
|
||||
buffer, bufflen, POS_OWNER_IP4))
|
||||
return 0;
|
||||
|
||||
if (!mangle_sip_packet(pskb, ctinfo, ct, &dptr, (*pskb)->len - dataoff,
|
||||
buffer, bufflen, POS_CONNECTION_IP4))
|
||||
return 0;
|
||||
|
||||
/* Mangle media port. */
|
||||
bufflen = sprintf(buffer, "%u", port);
|
||||
if (!mangle_sip_packet(pskb, ctinfo, ct, &dptr, (*pskb)->len - dataoff,
|
||||
buffer, bufflen, POS_MEDIA))
|
||||
return 0;
|
||||
|
||||
return mangle_content_len(pskb, ctinfo, ct, dptr);
|
||||
}
|
||||
|
||||
/* So, this packet has hit the connection tracking matching code.
|
||||
Mangle it, and change the expectation to match the new version. */
|
||||
static unsigned int ip_nat_sdp(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conntrack_expect *exp,
|
||||
const char *dptr)
|
||||
{
|
||||
struct nf_conn *ct = exp->master;
|
||||
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
|
||||
__be32 newip;
|
||||
u_int16_t port;
|
||||
|
||||
DEBUGP("ip_nat_sdp():\n");
|
||||
|
||||
/* Connection will come from reply */
|
||||
newip = ct->tuplehash[!dir].tuple.dst.u3.ip;
|
||||
|
||||
exp->tuple.dst.u3.ip = newip;
|
||||
exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port;
|
||||
exp->dir = !dir;
|
||||
|
||||
/* When you see the packet, we need to NAT it the same as the
|
||||
this one. */
|
||||
exp->expectfn = nf_nat_follow_master;
|
||||
|
||||
/* Try to get same port: if not, try to change it. */
|
||||
for (port = ntohs(exp->saved_proto.udp.port); port != 0; port++) {
|
||||
exp->tuple.dst.u.udp.port = htons(port);
|
||||
if (nf_conntrack_expect_related(exp) == 0)
|
||||
break;
|
||||
}
|
||||
|
||||
if (port == 0)
|
||||
return NF_DROP;
|
||||
|
||||
if (!mangle_sdp(pskb, ctinfo, ct, newip, port, dptr)) {
|
||||
nf_conntrack_unexpect_related(exp);
|
||||
return NF_DROP;
|
||||
}
|
||||
return NF_ACCEPT;
|
||||
}
|
||||
|
||||
static void __exit nf_nat_sip_fini(void)
|
||||
{
|
||||
rcu_assign_pointer(nf_nat_sip_hook, NULL);
|
||||
rcu_assign_pointer(nf_nat_sdp_hook, NULL);
|
||||
synchronize_rcu();
|
||||
}
|
||||
|
||||
static int __init nf_nat_sip_init(void)
|
||||
{
|
||||
BUG_ON(rcu_dereference(nf_nat_sip_hook));
|
||||
BUG_ON(rcu_dereference(nf_nat_sdp_hook));
|
||||
rcu_assign_pointer(nf_nat_sip_hook, ip_nat_sip);
|
||||
rcu_assign_pointer(nf_nat_sdp_hook, ip_nat_sdp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
module_init(nf_nat_sip_init);
|
||||
module_exit(nf_nat_sip_fini);
|
||||
@ -236,6 +236,18 @@ config NF_CONNTRACK_PPTP
|
||||
|
||||
To compile it as a module, choose M here. If unsure, say N.
|
||||
|
||||
config NF_CONNTRACK_SIP
|
||||
tristate "SIP protocol support (EXPERIMENTAL)"
|
||||
depends on EXPERIMENTAL && NF_CONNTRACK
|
||||
help
|
||||
SIP is an application-layer control protocol that can establish,
|
||||
modify, and terminate multimedia sessions (conferences) such as
|
||||
Internet telephony calls. With the ip_conntrack_sip and
|
||||
the nf_nat_sip modules you can support the protocol on a connection
|
||||
tracking/NATing firewall.
|
||||
|
||||
To compile it as a module, choose M here. If unsure, say N.
|
||||
|
||||
config NF_CT_NETLINK
|
||||
tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
|
||||
depends on EXPERIMENTAL && NF_CONNTRACK && NETFILTER_NETLINK
|
||||
|
||||
@ -29,6 +29,7 @@ obj-$(CONFIG_NF_CONNTRACK_H323) += nf_conntrack_h323.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_IRC) += nf_conntrack_irc.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_NETBIOS_NS) += nf_conntrack_netbios_ns.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_PPTP) += nf_conntrack_pptp.o
|
||||
obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o
|
||||
|
||||
# generic X tables
|
||||
obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
|
||||
|
||||
530
net/netfilter/nf_conntrack_sip.c
Normal file
530
net/netfilter/nf_conntrack_sip.c
Normal file
@ -0,0 +1,530 @@
|
||||
/* SIP extension for IP connection tracking.
|
||||
*
|
||||
* (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
|
||||
* based on RR's ip_conntrack_ftp.c and other modules.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/ctype.h>
|
||||
#include <linux/skbuff.h>
|
||||
#include <linux/inet.h>
|
||||
#include <linux/in.h>
|
||||
#include <linux/udp.h>
|
||||
|
||||
#include <net/netfilter/nf_conntrack.h>
|
||||
#include <net/netfilter/nf_conntrack_expect.h>
|
||||
#include <net/netfilter/nf_conntrack_helper.h>
|
||||
#include <linux/netfilter/nf_conntrack_sip.h>
|
||||
|
||||
#if 0
|
||||
#define DEBUGP printk
|
||||
#else
|
||||
#define DEBUGP(format, args...)
|
||||
#endif
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>");
|
||||
MODULE_DESCRIPTION("SIP connection tracking helper");
|
||||
MODULE_ALIAS("ip_conntrack_sip");
|
||||
|
||||
#define MAX_PORTS 8
|
||||
static unsigned short ports[MAX_PORTS];
|
||||
static int ports_c;
|
||||
module_param_array(ports, ushort, &ports_c, 0400);
|
||||
MODULE_PARM_DESC(ports, "port numbers of SIP servers");
|
||||
|
||||
static unsigned int sip_timeout __read_mostly = SIP_TIMEOUT;
|
||||
module_param(sip_timeout, uint, 0600);
|
||||
MODULE_PARM_DESC(sip_timeout, "timeout for the master SIP session");
|
||||
|
||||
unsigned int (*nf_nat_sip_hook)(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conn *ct,
|
||||
const char **dptr) __read_mostly;
|
||||
EXPORT_SYMBOL_GPL(nf_nat_sip_hook);
|
||||
|
||||
unsigned int (*nf_nat_sdp_hook)(struct sk_buff **pskb,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
struct nf_conntrack_expect *exp,
|
||||
const char *dptr) __read_mostly;
|
||||
EXPORT_SYMBOL_GPL(nf_nat_sdp_hook);
|
||||
|
||||
static int digits_len(struct nf_conn *, const char *, const char *, int *);
|
||||
static int epaddr_len(struct nf_conn *, const char *, const char *, int *);
|
||||
static int skp_digits_len(struct nf_conn *, const char *, const char *, int *);
|
||||
static int skp_epaddr_len(struct nf_conn *, const char *, const char *, int *);
|
||||
|
||||
struct sip_header_nfo {
|
||||
const char *lname;
|
||||
const char *sname;
|
||||
const char *ln_str;
|
||||
size_t lnlen;
|
||||
size_t snlen;
|
||||
size_t ln_strlen;
|
||||
int case_sensitive;
|
||||
int (*match_len)(struct nf_conn *, const char *,
|
||||
const char *, int *);
|
||||
};
|
||||
|
||||
static const struct sip_header_nfo ct_sip_hdrs[] = {
|
||||
[POS_REG_REQ_URI] = { /* SIP REGISTER request URI */
|
||||
.lname = "sip:",
|
||||
.lnlen = sizeof("sip:") - 1,
|
||||
.ln_str = ":",
|
||||
.ln_strlen = sizeof(":") - 1,
|
||||
.match_len = epaddr_len,
|
||||
},
|
||||
[POS_REQ_URI] = { /* SIP request URI */
|
||||
.lname = "sip:",
|
||||
.lnlen = sizeof("sip:") - 1,
|
||||
.ln_str = "@",
|
||||
.ln_strlen = sizeof("@") - 1,
|
||||
.match_len = epaddr_len,
|
||||
},
|
||||
[POS_FROM] = { /* SIP From header */
|
||||
.lname = "From:",
|
||||
.lnlen = sizeof("From:") - 1,
|
||||
.sname = "\r\nf:",
|
||||
.snlen = sizeof("\r\nf:") - 1,
|
||||
.ln_str = "sip:",
|
||||
.ln_strlen = sizeof("sip:") - 1,
|
||||
.match_len = skp_epaddr_len,
|
||||
},
|
||||
[POS_TO] = { /* SIP To header */
|
||||
.lname = "To:",
|
||||
.lnlen = sizeof("To:") - 1,
|
||||
.sname = "\r\nt:",
|
||||
.snlen = sizeof("\r\nt:") - 1,
|
||||
.ln_str = "sip:",
|
||||
.ln_strlen = sizeof("sip:") - 1,
|
||||
.match_len = skp_epaddr_len
|
||||
},
|
||||
[POS_VIA] = { /* SIP Via header */
|
||||
.lname = "Via:",
|
||||
.lnlen = sizeof("Via:") - 1,
|
||||
.sname = "\r\nv:",
|
||||
.snlen = sizeof("\r\nv:") - 1, /* rfc3261 "\r\n" */
|
||||
.ln_str = "UDP ",
|
||||
.ln_strlen = sizeof("UDP ") - 1,
|
||||
.match_len = epaddr_len,
|
||||
},
|
||||
[POS_CONTACT] = { /* SIP Contact header */
|
||||
.lname = "Contact:",
|
||||
.lnlen = sizeof("Contact:") - 1,
|
||||
.sname = "\r\nm:",
|
||||
.snlen = sizeof("\r\nm:") - 1,
|
||||
.ln_str = "sip:",
|
||||
.ln_strlen = sizeof("sip:") - 1,
|
||||
.match_len = skp_epaddr_len
|
||||
},
|
||||
[POS_CONTENT] = { /* SIP Content length header */
|
||||
.lname = "Content-Length:",
|
||||
.lnlen = sizeof("Content-Length:") - 1,
|
||||
.sname = "\r\nl:",
|
||||
.snlen = sizeof("\r\nl:") - 1,
|
||||
.ln_str = ":",
|
||||
.ln_strlen = sizeof(":") - 1,
|
||||
.match_len = skp_digits_len
|
||||
},
|
||||
[POS_MEDIA] = { /* SDP media info */
|
||||
.case_sensitive = 1,
|
||||
.lname = "\nm=",
|
||||
.lnlen = sizeof("\nm=") - 1,
|
||||
.sname = "\rm=",
|
||||
.snlen = sizeof("\rm=") - 1,
|
||||
.ln_str = "audio ",
|
||||
.ln_strlen = sizeof("audio ") - 1,
|
||||
.match_len = digits_len
|
||||
},
|
||||
[POS_OWNER_IP4] = { /* SDP owner address*/
|
||||
.case_sensitive = 1,
|
||||
.lname = "\no=",
|
||||
.lnlen = sizeof("\no=") - 1,
|
||||
.sname = "\ro=",
|
||||
.snlen = sizeof("\ro=") - 1,
|
||||
.ln_str = "IN IP4 ",
|
||||
.ln_strlen = sizeof("IN IP4 ") - 1,
|
||||
.match_len = epaddr_len
|
||||
},
|
||||
[POS_CONNECTION_IP4] = {/* SDP connection info */
|
||||
.case_sensitive = 1,
|
||||
.lname = "\nc=",
|
||||
.lnlen = sizeof("\nc=") - 1,
|
||||
.sname = "\rc=",
|
||||
.snlen = sizeof("\rc=") - 1,
|
||||
.ln_str = "IN IP4 ",
|
||||
.ln_strlen = sizeof("IN IP4 ") - 1,
|
||||
.match_len = epaddr_len
|
||||
},
|
||||
[POS_OWNER_IP6] = { /* SDP owner address*/
|
||||
.case_sensitive = 1,
|
||||
.lname = "\no=",
|
||||
.lnlen = sizeof("\no=") - 1,
|
||||
.sname = "\ro=",
|
||||
.snlen = sizeof("\ro=") - 1,
|
||||
.ln_str = "IN IP6 ",
|
||||
.ln_strlen = sizeof("IN IP6 ") - 1,
|
||||
.match_len = epaddr_len
|
||||
},
|
||||
[POS_CONNECTION_IP6] = {/* SDP connection info */
|
||||
.case_sensitive = 1,
|
||||
.lname = "\nc=",
|
||||
.lnlen = sizeof("\nc=") - 1,
|
||||
.sname = "\rc=",
|
||||
.snlen = sizeof("\rc=") - 1,
|
||||
.ln_str = "IN IP6 ",
|
||||
.ln_strlen = sizeof("IN IP6 ") - 1,
|
||||
.match_len = epaddr_len
|
||||
},
|
||||
[POS_SDP_HEADER] = { /* SDP version header */
|
||||
.case_sensitive = 1,
|
||||
.lname = "\nv=",
|
||||
.lnlen = sizeof("\nv=") - 1,
|
||||
.sname = "\rv=",
|
||||
.snlen = sizeof("\rv=") - 1,
|
||||
.ln_str = "=",
|
||||
.ln_strlen = sizeof("=") - 1,
|
||||
.match_len = digits_len
|
||||
}
|
||||
};
|
||||
|
||||
/* get line lenght until first CR or LF seen. */
|
||||
int ct_sip_lnlen(const char *line, const char *limit)
|
||||
{
|
||||
const char *k = line;
|
||||
|
||||
while ((line <= limit) && (*line == '\r' || *line == '\n'))
|
||||
line++;
|
||||
|
||||
while (line <= limit) {
|
||||
if (*line == '\r' || *line == '\n')
|
||||
break;
|
||||
line++;
|
||||
}
|
||||
return line - k;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(ct_sip_lnlen);
|
||||
|
||||
/* Linear string search, case sensitive. */
|
||||
const char *ct_sip_search(const char *needle, const char *haystack,
|
||||
size_t needle_len, size_t haystack_len,
|
||||
int case_sensitive)
|
||||
{
|
||||
const char *limit = haystack + (haystack_len - needle_len);
|
||||
|
||||
while (haystack <= limit) {
|
||||
if (case_sensitive) {
|
||||
if (strncmp(haystack, needle, needle_len) == 0)
|
||||
return haystack;
|
||||
} else {
|
||||
if (strnicmp(haystack, needle, needle_len) == 0)
|
||||
return haystack;
|
||||
}
|
||||
haystack++;
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(ct_sip_search);
|
||||
|
||||
static int digits_len(struct nf_conn *ct, const char *dptr,
|
||||
const char *limit, int *shift)
|
||||
{
|
||||
int len = 0;
|
||||
while (dptr <= limit && isdigit(*dptr)) {
|
||||
dptr++;
|
||||
len++;
|
||||
}
|
||||
return len;
|
||||
}
|
||||
|
||||
/* get digits lenght, skiping blank spaces. */
|
||||
static int skp_digits_len(struct nf_conn *ct, const char *dptr,
|
||||
const char *limit, int *shift)
|
||||
{
|
||||
for (; dptr <= limit && *dptr == ' '; dptr++)
|
||||
(*shift)++;
|
||||
|
||||
return digits_len(ct, dptr, limit, shift);
|
||||
}
|
||||
|
||||
static int parse_addr(struct nf_conn *ct, const char *cp, const char **endp,
|
||||
union nf_conntrack_address *addr, const char *limit)
|
||||
{
|
||||
const char *end;
|
||||
int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
|
||||
int ret = 0;
|
||||
|
||||
switch (family) {
|
||||
case AF_INET:
|
||||
ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end);
|
||||
break;
|
||||
case AF_INET6:
|
||||
ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end);
|
||||
break;
|
||||
default:
|
||||
BUG();
|
||||
}
|
||||
|
||||
if (ret == 0 || end == cp)
|
||||
return 0;
|
||||
if (endp)
|
||||
*endp = end;
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* skip ip address. returns its length. */
|
||||
static int epaddr_len(struct nf_conn *ct, const char *dptr,
|
||||
const char *limit, int *shift)
|
||||
{
|
||||
union nf_conntrack_address addr;
|
||||
const char *aux = dptr;
|
||||
|
||||
if (!parse_addr(ct, dptr, &dptr, &addr, limit)) {
|
||||
DEBUGP("ip: %s parse failed.!\n", dptr);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Port number */
|
||||
if (*dptr == ':') {
|
||||
dptr++;
|
||||
dptr += digits_len(ct, dptr, limit, shift);
|
||||
}
|
||||
return dptr - aux;
|
||||
}
|
||||
|
||||
/* get address length, skiping user info. */
|
||||
static int skp_epaddr_len(struct nf_conn *ct, const char *dptr,
|
||||
const char *limit, int *shift)
|
||||
{
|
||||
int s = *shift;
|
||||
|
||||
for (; dptr <= limit && *dptr != '@'; dptr++)
|
||||
(*shift)++;
|
||||
|
||||
if (*dptr == '@') {
|
||||
dptr++;
|
||||
(*shift)++;
|
||||
} else
|
||||
*shift = s;
|
||||
|
||||
return epaddr_len(ct, dptr, limit, shift);
|
||||
}
|
||||
|
||||
/* Returns 0 if not found, -1 error parsing. */
|
||||
int ct_sip_get_info(struct nf_conn *ct,
|
||||
const char *dptr, size_t dlen,
|
||||
unsigned int *matchoff,
|
||||
unsigned int *matchlen,
|
||||
enum sip_header_pos pos)
|
||||
{
|
||||
const struct sip_header_nfo *hnfo = &ct_sip_hdrs[pos];
|
||||
const char *limit, *aux, *k = dptr;
|
||||
int shift = 0;
|
||||
|
||||
limit = dptr + (dlen - hnfo->lnlen);
|
||||
|
||||
while (dptr <= limit) {
|
||||
if ((strncmp(dptr, hnfo->lname, hnfo->lnlen) != 0) &&
|
||||
(strncmp(dptr, hnfo->sname, hnfo->snlen) != 0)) {
|
||||
dptr++;
|
||||
continue;
|
||||
}
|
||||
aux = ct_sip_search(hnfo->ln_str, dptr, hnfo->ln_strlen,
|
||||
ct_sip_lnlen(dptr, limit),
|
||||
hnfo->case_sensitive);
|
||||
if (!aux) {
|
||||
DEBUGP("'%s' not found in '%s'.\n", hnfo->ln_str,
|
||||
hnfo->lname);
|
||||
return -1;
|
||||
}
|
||||
aux += hnfo->ln_strlen;
|
||||
|
||||
*matchlen = hnfo->match_len(ct, aux, limit, &shift);
|
||||
if (!*matchlen)
|
||||
return -1;
|
||||
|
||||
*matchoff = (aux - k) + shift;
|
||||
|
||||
DEBUGP("%s match succeeded! - len: %u\n", hnfo->lname,
|
||||
*matchlen);
|
||||
return 1;
|
||||
}
|
||||
DEBUGP("%s header not found.\n", hnfo->lname);
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(ct_sip_get_info);
|
||||
|
||||
static int set_expected_rtp(struct sk_buff **pskb,
|
||||
struct nf_conn *ct,
|
||||
enum ip_conntrack_info ctinfo,
|
||||
union nf_conntrack_address *addr,
|
||||
__be16 port,
|
||||
const char *dptr)
|
||||
{
|
||||
struct nf_conntrack_expect *exp;
|
||||
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
|
||||
int family = ct->tuplehash[!dir].tuple.src.l3num;
|
||||
int ret;
|
||||
typeof(nf_nat_sdp_hook) nf_nat_sdp;
|
||||
|
||||
exp = nf_conntrack_expect_alloc(ct);
|
||||
if (exp == NULL)
|
||||
return NF_DROP;
|
||||
nf_conntrack_expect_init(exp, family,
|
||||
&ct->tuplehash[!dir].tuple.src.u3, addr,
|
||||
IPPROTO_UDP, NULL, &port);
|
||||
|
||||
nf_nat_sdp = rcu_dereference(nf_nat_sdp_hook);
|
||||
if (nf_nat_sdp && ct->status & IPS_NAT_MASK)
|
||||
ret = nf_nat_sdp(pskb, ctinfo, exp, dptr);
|
||||
else {
|
||||
if (nf_conntrack_expect_related(exp) != 0)
|
||||
ret = NF_DROP;
|
||||
else
|
||||
ret = NF_ACCEPT;
|
||||
}
|
||||
nf_conntrack_expect_put(exp);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int sip_help(struct sk_buff **pskb,
|
||||
unsigned int protoff,
|
||||
struct nf_conn *ct,
|
||||
enum ip_conntrack_info ctinfo)
|
||||
{
|
||||
int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
|
||||
union nf_conntrack_address addr;
|
||||
unsigned int dataoff, datalen;
|
||||
const char *dptr;
|
||||
int ret = NF_ACCEPT;
|
||||
int matchoff, matchlen;
|
||||
u_int16_t port;
|
||||
enum sip_header_pos pos;
|
||||
typeof(nf_nat_sip_hook) nf_nat_sip;
|
||||
|
||||
/* No Data ? */
|
||||
dataoff = protoff + sizeof(struct udphdr);
|
||||
if (dataoff >= (*pskb)->len)
|
||||
return NF_ACCEPT;
|
||||
|
||||
nf_ct_refresh(ct, *pskb, sip_timeout * HZ);
|
||||
|
||||
if (!skb_is_nonlinear(*pskb))
|
||||
dptr = (*pskb)->data + dataoff;
|
||||
else {
|
||||
DEBUGP("Copy of skbuff not supported yet.\n");
|
||||
goto out;
|
||||
}
|
||||
|
||||
nf_nat_sip = rcu_dereference(nf_nat_sip_hook);
|
||||
if (nf_nat_sip && ct->status & IPS_NAT_MASK) {
|
||||
if (!nf_nat_sip(pskb, ctinfo, ct, &dptr)) {
|
||||
ret = NF_DROP;
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
|
||||
datalen = (*pskb)->len - dataoff;
|
||||
if (datalen < sizeof("SIP/2.0 200") - 1)
|
||||
goto out;
|
||||
|
||||
/* RTP info only in some SDP pkts */
|
||||
if (memcmp(dptr, "INVITE", sizeof("INVITE") - 1) != 0 &&
|
||||
memcmp(dptr, "SIP/2.0 200", sizeof("SIP/2.0 200") - 1) != 0) {
|
||||
goto out;
|
||||
}
|
||||
/* Get address and port from SDP packet. */
|
||||
pos = family == AF_INET ? POS_CONNECTION_IP4 : POS_CONNECTION_IP6;
|
||||
if (ct_sip_get_info(ct, dptr, datalen, &matchoff, &matchlen, pos) > 0) {
|
||||
|
||||
/* We'll drop only if there are parse problems. */
|
||||
if (!parse_addr(ct, dptr + matchoff, NULL, &addr,
|
||||
dptr + datalen)) {
|
||||
ret = NF_DROP;
|
||||
goto out;
|
||||
}
|
||||
if (ct_sip_get_info(ct, dptr, datalen, &matchoff, &matchlen,
|
||||
POS_MEDIA) > 0) {
|
||||
|
||||
port = simple_strtoul(dptr + matchoff, NULL, 10);
|
||||
if (port < 1024) {
|
||||
ret = NF_DROP;
|
||||
goto out;
|
||||
}
|
||||
ret = set_expected_rtp(pskb, ct, ctinfo, &addr,
|
||||
htons(port), dptr);
|
||||
}
|
||||
}
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static struct nf_conntrack_helper sip[MAX_PORTS][2] __read_mostly;
|
||||
static char sip_names[MAX_PORTS][2][sizeof("sip-65535")] __read_mostly;
|
||||
|
||||
static void nf_conntrack_sip_fini(void)
|
||||
{
|
||||
int i, j;
|
||||
|
||||
for (i = 0; i < ports_c; i++) {
|
||||
for (j = 0; j < 2; j++) {
|
||||
if (sip[i][j].me == NULL)
|
||||
continue;
|
||||
nf_conntrack_helper_unregister(&sip[i][j]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static int __init nf_conntrack_sip_init(void)
|
||||
{
|
||||
int i, j, ret;
|
||||
char *tmpname;
|
||||
|
||||
if (ports_c == 0)
|
||||
ports[ports_c++] = SIP_PORT;
|
||||
|
||||
for (i = 0; i < ports_c; i++) {
|
||||
memset(&sip[i], 0, sizeof(sip[i]));
|
||||
|
||||
sip[i][0].tuple.src.l3num = AF_INET;
|
||||
sip[i][1].tuple.src.l3num = AF_INET6;
|
||||
for (j = 0; j < 2; j++) {
|
||||
sip[i][j].tuple.dst.protonum = IPPROTO_UDP;
|
||||
sip[i][j].tuple.src.u.udp.port = htons(ports[i]);
|
||||
sip[i][j].mask.src.l3num = 0xFFFF;
|
||||
sip[i][j].mask.src.u.udp.port = htons(0xFFFF);
|
||||
sip[i][j].mask.dst.protonum = 0xFF;
|
||||
sip[i][j].max_expected = 2;
|
||||
sip[i][j].timeout = 3 * 60; /* 3 minutes */
|
||||
sip[i][j].me = THIS_MODULE;
|
||||
sip[i][j].help = sip_help;
|
||||
|
||||
tmpname = &sip_names[i][j][0];
|
||||
if (ports[i] == SIP_PORT)
|
||||
sprintf(tmpname, "sip");
|
||||
else
|
||||
sprintf(tmpname, "sip-%u", i);
|
||||
sip[i][j].name = tmpname;
|
||||
|
||||
DEBUGP("port #%u: %u\n", i, ports[i]);
|
||||
|
||||
ret = nf_conntrack_helper_register(&sip[i][j]);
|
||||
if (ret) {
|
||||
printk("nf_ct_sip: failed to register helper "
|
||||
"for pf: %u port: %u\n",
|
||||
sip[i][j].tuple.src.l3num, ports[i]);
|
||||
nf_conntrack_sip_fini();
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
module_init(nf_conntrack_sip_init);
|
||||
module_exit(nf_conntrack_sip_fini);
|
||||
Loading…
Reference in New Issue
Block a user