diff options
Diffstat (limited to 'net/ipv4/netfilter/ip_nat_sip.c')
-rw-r--r-- | net/ipv4/netfilter/ip_nat_sip.c | 282 |
1 files changed, 0 insertions, 282 deletions
diff --git a/net/ipv4/netfilter/ip_nat_sip.c b/net/ipv4/netfilter/ip_nat_sip.c deleted file mode 100644 index 84953601762..00000000000 --- a/net/ipv4/netfilter/ip_nat_sip.c +++ /dev/null @@ -1,282 +0,0 @@ -/* 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 <linux/netfilter_ipv4.h> -#include <linux/netfilter_ipv4/ip_nat.h> -#include <linux/netfilter_ipv4/ip_nat_helper.h> -#include <linux/netfilter_ipv4/ip_conntrack_helper.h> -#include <linux/netfilter_ipv4/ip_conntrack_sip.h> - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>"); -MODULE_DESCRIPTION("SIP NAT helper"); - -#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 ip_conntrack *ct, struct addr_map *map) -{ - struct ip_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.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.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 ip_conntrack *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(*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 (!ip_nat_mangle_udp_packet(pskb, ct, ctinfo, - matchoff, matchlen, addr, addrlen)) - return 0; - *dptr = (*pskb)->data + ip_hdrlen(*pskb) + sizeof(struct udphdr); - return 1; - -} - -static unsigned int ip_nat_sip(struct sk_buff **pskb, - enum ip_conntrack_info ctinfo, - struct ip_conntrack *ct, - const char **dptr) -{ - enum sip_header_pos pos; - struct addr_map map; - int dataoff, datalen; - - dataoff = ip_hdrlen(*pskb) + 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 ip_conntrack *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(*dptr, dlen, &matchoff, &matchlen, pos) <= 0) - return 0; - - if (!ip_nat_mangle_udp_packet(pskb, ct, ctinfo, - matchoff, matchlen, buffer, bufflen)) - return 0; - - /* We need to reload this. Thanks Patrick. */ - *dptr = (*pskb)->data + ip_hdrlen(*pskb) + sizeof(struct udphdr); - return 1; -} - -static int mangle_content_len(struct sk_buff **pskb, - enum ip_conntrack_info ctinfo, - struct ip_conntrack *ct, - const char *dptr) -{ - unsigned int dataoff, matchoff, matchlen; - char buffer[sizeof("65536")]; - int bufflen; - - dataoff = ip_hdrlen(*pskb) + sizeof(struct udphdr); - - /* Get actual SDP lenght */ - if (ct_sip_get_info(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 lenght */ - if (ct_sip_get_info(dptr, (*pskb)->len - dataoff, &matchoff, - &matchlen, POS_CONTENT) > 0) { - - bufflen = sprintf(buffer, "%u", c_len); - - return ip_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 ip_conntrack *ct, - __be32 newip, u_int16_t port, - const char *dptr) -{ - char buffer[sizeof("nnn.nnn.nnn.nnn")]; - unsigned int dataoff, bufflen; - - dataoff = ip_hdrlen(*pskb) + 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)) - return 0; - - if (!mangle_sip_packet(pskb, ctinfo, ct, &dptr, (*pskb)->len - dataoff, - buffer, bufflen, POS_CONNECTION)) - 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 ip_conntrack_expect *exp, - const char *dptr) -{ - struct ip_conntrack *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.ip; - - exp->tuple.dst.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 = ip_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 (ip_conntrack_expect_related(exp) == 0) - break; - } - - if (port == 0) - return NF_DROP; - - if (!mangle_sdp(pskb, ctinfo, ct, newip, port, dptr)) { - ip_conntrack_unexpect_related(exp); - return NF_DROP; - } - return NF_ACCEPT; -} - -static void __exit fini(void) -{ - rcu_assign_pointer(ip_nat_sip_hook, NULL); - rcu_assign_pointer(ip_nat_sdp_hook, NULL); - synchronize_rcu(); -} - -static int __init init(void) -{ - BUG_ON(rcu_dereference(ip_nat_sip_hook)); - BUG_ON(rcu_dereference(ip_nat_sdp_hook)); - rcu_assign_pointer(ip_nat_sip_hook, ip_nat_sip); - rcu_assign_pointer(ip_nat_sdp_hook, ip_nat_sdp); - return 0; -} - -module_init(init); -module_exit(fini); |