diff -urN linux-2.4.32/net/ipv4/netfilter/Config.in linux-2.4.32.new/net/ipv4/netfilter/Config.in --- linux-2.4.32/net/ipv4/netfilter/Config.in 2006-03-01 00:49:36.652505800 +0100 +++ linux-2.4.32.new/net/ipv4/netfilter/Config.in 2006-03-01 00:50:18.692114808 +0100 @@ -15,6 +15,7 @@ dep_tristate ' Connection byte counter support' CONFIG_IP_NF_MATCH_CONNBYTES $CONFIG_IP_NF_CT_ACCT $CONFIG_IP_NF_CONNTRACK $CONFIG_IP_NF_IPTABLES dep_tristate ' GRE protocol support' CONFIG_IP_NF_CT_PROTO_GRE $CONFIG_IP_NF_CONNTRACK dep_tristate ' PPTP protocol support' CONFIG_IP_NF_PPTP $CONFIG_IP_NF_CT_PROTO_GRE + dep_tristate ' H.323 (netmeeting) support' CONFIG_IP_NF_H323 $CONFIG_IP_NF_CONNTRACK fi if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then @@ -111,6 +112,13 @@ define_tristate CONFIG_IP_NF_NAT_AMANDA $CONFIG_IP_NF_NAT fi fi + if [ "$CONFIG_IP_NF_H323" = "m" ]; then + define_tristate CONFIG_IP_NF_NAT_H323 m + else + if [ "$CONFIG_IP_NF_H323" = "y" ]; then + define_tristate CONFIG_IP_NF_NAT_H323 $CONFIG_IP_NF_NAT + fi + fi if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then dep_tristate ' Basic SNMP-ALG support (EXPERIMENTAL)' CONFIG_IP_NF_NAT_SNMP_BASIC $CONFIG_IP_NF_NAT fi diff -urN linux-2.4.32/net/ipv4/netfilter/Makefile linux-2.4.32.new/net/ipv4/netfilter/Makefile --- linux-2.4.32/net/ipv4/netfilter/Makefile 2006-03-01 00:49:36.654505496 +0100 +++ linux-2.4.32.new/net/ipv4/netfilter/Makefile 2006-03-01 00:50:18.693114656 +0100 @@ -53,6 +53,10 @@ ifdef CONFIG_IP_NF_NAT_PPTP export-objs += ip_conntrack_pptp.o endif +obj-$(CONFIG_IP_NF_H323) += ip_conntrack_h323.o +ifdef CONFIG_IP_NF_NAT_H323 + export-objs += ip_conntrack_h323.o +endif # NAT helpers @@ -62,6 +66,7 @@ obj-$(CONFIG_IP_NF_NAT_IRC) += ip_nat_irc.o obj-$(CONFIG_IP_NF_NAT_PROTO_GRE) += ip_nat_proto_gre.o obj-$(CONFIG_IP_NF_NAT_PPTP) += ip_nat_pptp.o +obj-$(CONFIG_IP_NF_NAT_H323) += ip_nat_h323.o # generic IP tables obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o diff -urN linux-2.4.32/net/ipv4/netfilter/ip_conntrack_h323.c linux-2.4.32.new/net/ipv4/netfilter/ip_conntrack_h323.c --- linux-2.4.32/net/ipv4/netfilter/ip_conntrack_h323.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.4.32.new/net/ipv4/netfilter/ip_conntrack_h323.c 2006-03-01 00:50:18.694114504 +0100 @@ -0,0 +1,302 @@ +/* + * H.323 'brute force' extension for H.323 connection tracking. + * Jozsef Kadlecsik + * + * Based on ip_masq_h323.c for 2.2 kernels from CoRiTel, Sofia project. + * (http://www.coritel.it/projects/sofia/nat/) + * Uses Sampsa Ranta's excellent idea on using expectfn to 'bind' + * the unregistered helpers to the conntrack entries. + */ + + +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Jozsef Kadlecsik "); +MODULE_DESCRIPTION("H.323 'brute force' connection tracking module"); +MODULE_LICENSE("GPL"); + +DECLARE_LOCK(ip_h323_lock); +struct module *ip_conntrack_h323 = THIS_MODULE; + +#define DEBUGP(format, args...) + +static int h245_help(const struct iphdr *iph, size_t len, + struct ip_conntrack *ct, + enum ip_conntrack_info ctinfo) +{ + struct tcphdr *tcph = (void *)iph + iph->ihl * 4; + unsigned char *data = (unsigned char *) tcph + tcph->doff * 4; + unsigned char *data_limit; + u_int32_t tcplen = len - iph->ihl * 4; + u_int32_t datalen = tcplen - tcph->doff * 4; + int dir = CTINFO2DIR(ctinfo); + struct ip_ct_h225_master *info = &ct->help.ct_h225_info; + struct ip_conntrack_expect expect, *exp = &expect; + struct ip_ct_h225_expect *exp_info = &exp->help.exp_h225_info; + u_int16_t data_port; + u_int32_t data_ip; + unsigned int i; + + DEBUGP("ct_h245_help: help entered %u.%u.%u.%u:%u->%u.%u.%u.%u:%u\n", + NIPQUAD(iph->saddr), ntohs(tcph->source), + NIPQUAD(iph->daddr), ntohs(tcph->dest)); + + /* Can't track connections formed before we registered */ + if (!info) + return NF_ACCEPT; + + /* Until there's been traffic both ways, don't look in packets. */ + if (ctinfo != IP_CT_ESTABLISHED + && ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) { + DEBUGP("ct_h245_help: Conntrackinfo = %u\n", ctinfo); + return NF_ACCEPT; + } + + /* Not whole TCP header or too short packet? */ + if (tcplen < sizeof(struct tcphdr) || tcplen < tcph->doff * 4 + 5) { + DEBUGP("ct_h245_help: tcplen = %u\n", (unsigned)tcplen); + return NF_ACCEPT; + } + + /* Checksum invalid? Ignore. */ + if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr, + csum_partial((char *)tcph, tcplen, 0))) { + DEBUGP("ct_h245_help: bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n", + tcph, tcplen, NIPQUAD(iph->saddr), + NIPQUAD(iph->daddr)); + return NF_ACCEPT; + } + + data_limit = (unsigned char *) data + datalen; + /* bytes: 0123 45 + ipadrr port */ + for (i = 0; data < (data_limit - 5); data++, i++) { + memcpy(&data_ip, data, sizeof(u_int32_t)); + if (data_ip == iph->saddr) { + memcpy(&data_port, data + 4, sizeof(u_int16_t)); + memset(&expect, 0, sizeof(expect)); + /* update the H.225 info */ + DEBUGP("ct_h245_help: new RTCP/RTP requested %u.%u.%u.%u:->%u.%u.%u.%u:%u\n", + NIPQUAD(ct->tuplehash[!dir].tuple.src.ip), + NIPQUAD(iph->saddr), ntohs(data_port)); + LOCK_BH(&ip_h323_lock); + info->is_h225 = H225_PORT + 1; + exp_info->port = data_port; + exp_info->dir = dir; + exp_info->offset = i; + + exp->seq = ntohl(tcph->seq) + i; + + exp->tuple = ((struct ip_conntrack_tuple) + { { ct->tuplehash[!dir].tuple.src.ip, + { 0 } }, + { data_ip, + { data_port }, + IPPROTO_UDP }}); + exp->mask = ((struct ip_conntrack_tuple) + { { 0xFFFFFFFF, { 0 } }, + { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }}); + + exp->expectfn = NULL; + + /* Ignore failure; should only happen with NAT */ + ip_conntrack_expect_related(ct, exp); + + UNLOCK_BH(&ip_h323_lock); + } + } + + return NF_ACCEPT; + +} + +/* H.245 helper is not registered! */ +static struct ip_conntrack_helper h245 = + { { NULL, NULL }, + "H.245", /* name */ + IP_CT_HELPER_F_REUSE_EXPECT, /* flags */ + NULL, /* module */ + 8, /* max_ expected */ + 240, /* timeout */ + { { 0, { 0 } }, /* tuple */ + { 0, { 0 }, IPPROTO_TCP } }, + { { 0, { 0xFFFF } }, /* mask */ + { 0, { 0 }, 0xFFFF } }, + h245_help /* helper */ + }; + +static int h225_expect(struct ip_conntrack *ct) +{ + WRITE_LOCK(&ip_conntrack_lock); + ct->helper = &h245; + DEBUGP("h225_expect: helper for %p added\n", ct); + WRITE_UNLOCK(&ip_conntrack_lock); + + return NF_ACCEPT; /* unused */ +} + +static int h225_help(const struct iphdr *iph, size_t len, + struct ip_conntrack *ct, + enum ip_conntrack_info ctinfo) +{ + struct tcphdr *tcph = (void *)iph + iph->ihl * 4; + unsigned char *data = (unsigned char *) tcph + tcph->doff * 4; + unsigned char *data_limit; + u_int32_t tcplen = len - iph->ihl * 4; + u_int32_t datalen = tcplen - tcph->doff * 4; + int dir = CTINFO2DIR(ctinfo); + struct ip_ct_h225_master *info = &ct->help.ct_h225_info; + struct ip_conntrack_expect expect, *exp = &expect; + struct ip_ct_h225_expect *exp_info = &exp->help.exp_h225_info; + u_int16_t data_port; + u_int32_t data_ip; + unsigned int i; + + DEBUGP("ct_h225_help: help entered %u.%u.%u.%u:%u->%u.%u.%u.%u:%u\n", + NIPQUAD(iph->saddr), ntohs(tcph->source), + NIPQUAD(iph->daddr), ntohs(tcph->dest)); + + /* Can't track connections formed before we registered */ + if (!info) + return NF_ACCEPT; + + /* Until there's been traffic both ways, don't look in packets. */ + if (ctinfo != IP_CT_ESTABLISHED + && ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) { + DEBUGP("ct_h225_help: Conntrackinfo = %u\n", ctinfo); + return NF_ACCEPT; + } + + /* Not whole TCP header or too short packet? */ + if (tcplen < sizeof(struct tcphdr) || tcplen < tcph->doff * 4 + 5) { + DEBUGP("ct_h225_help: tcplen = %u\n", (unsigned)tcplen); + return NF_ACCEPT; + } + + /* Checksum invalid? Ignore. */ + if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr, + csum_partial((char *)tcph, tcplen, 0))) { + DEBUGP("ct_h225_help: bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n", + tcph, tcplen, NIPQUAD(iph->saddr), + NIPQUAD(iph->daddr)); + return NF_ACCEPT; + } + + data_limit = (unsigned char *) data + datalen; + /* bytes: 0123 45 + ipadrr port */ + for (i = 0; data < (data_limit - 5); data++, i++) { + memcpy(&data_ip, data, sizeof(u_int32_t)); + if (data_ip == iph->saddr) { + memcpy(&data_port, data + 4, sizeof(u_int16_t)); + if (data_port == tcph->source) { + /* Signal address */ + DEBUGP("ct_h225_help: sourceCallSignalAddress from %u.%u.%u.%u\n", + NIPQUAD(iph->saddr)); + /* Update the H.225 info so that NAT can mangle the address/port + even when we have no expected connection! */ +#ifdef CONFIG_IP_NF_NAT_NEEDED + LOCK_BH(&ip_h323_lock); + info->dir = dir; + info->seq[IP_CT_DIR_ORIGINAL] = ntohl(tcph->seq) + i; + info->offset[IP_CT_DIR_ORIGINAL] = i; + UNLOCK_BH(&ip_h323_lock); +#endif + } else { + memset(&expect, 0, sizeof(expect)); + + /* update the H.225 info */ + LOCK_BH(&ip_h323_lock); + info->is_h225 = H225_PORT; + exp_info->port = data_port; + exp_info->dir = dir; + exp_info->offset = i; + + exp->seq = ntohl(tcph->seq) + i; + + exp->tuple = ((struct ip_conntrack_tuple) + { { ct->tuplehash[!dir].tuple.src.ip, + { 0 } }, + { data_ip, + { data_port }, + IPPROTO_TCP }}); + exp->mask = ((struct ip_conntrack_tuple) + { { 0xFFFFFFFF, { 0 } }, + { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }}); + + exp->expectfn = h225_expect; + + /* Ignore failure */ + ip_conntrack_expect_related(ct, exp); + + DEBUGP("ct_h225_help: new H.245 requested %u.%u.%u.%u->%u.%u.%u.%u:%u\n", + NIPQUAD(ct->tuplehash[!dir].tuple.src.ip), + NIPQUAD(iph->saddr), ntohs(data_port)); + + UNLOCK_BH(&ip_h323_lock); + } +#ifdef CONFIG_IP_NF_NAT_NEEDED + } else if (data_ip == iph->daddr) { + memcpy(&data_port, data + 4, sizeof(u_int16_t)); + if (data_port == tcph->dest) { + /* Signal address */ + DEBUGP("ct_h225_help: destCallSignalAddress %u.%u.%u.%u\n", + NIPQUAD(iph->daddr)); + /* Update the H.225 info so that NAT can mangle the address/port + even when we have no expected connection! */ + LOCK_BH(&ip_h323_lock); + info->dir = dir; + info->seq[IP_CT_DIR_REPLY] = ntohl(tcph->seq) + i; + info->offset[IP_CT_DIR_REPLY] = i; + UNLOCK_BH(&ip_h323_lock); + } +#endif + } + } + + return NF_ACCEPT; + +} + +static struct ip_conntrack_helper h225 = + { { NULL, NULL }, + "H.225", /* name */ + IP_CT_HELPER_F_REUSE_EXPECT, /* flags */ + THIS_MODULE, /* module */ + 2, /* max_expected */ + 240, /* timeout */ + { { 0, { __constant_htons(H225_PORT) } }, /* tuple */ + { 0, { 0 }, IPPROTO_TCP } }, + { { 0, { 0xFFFF } }, /* mask */ + { 0, { 0 }, 0xFFFF } }, + h225_help /* helper */ + }; + +static int __init init(void) +{ + return ip_conntrack_helper_register(&h225); +} + +static void __exit fini(void) +{ + /* Unregister H.225 helper */ + ip_conntrack_helper_unregister(&h225); +} + +#ifdef CONFIG_IP_NF_NAT_NEEDED +EXPORT_SYMBOL(ip_h323_lock); +#endif + +module_init(init); +module_exit(fini); diff -urN linux-2.4.32/net/ipv4/netfilter/ip_nat_h323.c linux-2.4.32.new/net/ipv4/netfilter/ip_nat_h323.c --- linux-2.4.32/net/ipv4/netfilter/ip_nat_h323.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.4.32.new/net/ipv4/netfilter/ip_nat_h323.c 2006-03-01 00:50:18.698113896 +0100 @@ -0,0 +1,403 @@ +/* + * H.323 'brute force' extension for NAT alteration. + * Jozsef Kadlecsik + * + * Based on ip_masq_h323.c for 2.2 kernels from CoRiTel, Sofia project. + * (http://www.coritel.it/projects/sofia/nat.html) + * Uses Sampsa Ranta's excellent idea on using expectfn to 'bind' + * the unregistered helpers to the conntrack entries. + */ + + +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Jozsef Kadlecsik "); +MODULE_DESCRIPTION("H.323 'brute force' connection tracking module"); +MODULE_LICENSE("GPL"); + +DECLARE_LOCK_EXTERN(ip_h323_lock); +struct module *ip_nat_h323 = THIS_MODULE; + +#define DEBUGP(format, args...) + + +static unsigned int +h225_nat_expected(struct sk_buff **pskb, + unsigned int hooknum, + struct ip_conntrack *ct, + struct ip_nat_info *info); + +static unsigned int h225_nat_help(struct ip_conntrack *ct, + struct ip_conntrack_expect *exp, + struct ip_nat_info *info, + enum ip_conntrack_info ctinfo, + unsigned int hooknum, + struct sk_buff **pskb); + +static struct ip_nat_helper h245 = + { { NULL, NULL }, + "H.245", /* name */ + 0, /* flags */ + NULL, /* module */ + { { 0, { 0 } }, /* tuple */ + { 0, { 0 }, IPPROTO_TCP } }, + { { 0, { 0xFFFF } }, /* mask */ + { 0, { 0 }, 0xFFFF } }, + h225_nat_help, /* helper */ + h225_nat_expected /* expectfn */ + }; + +static unsigned int +h225_nat_expected(struct sk_buff **pskb, + unsigned int hooknum, + struct ip_conntrack *ct, + struct ip_nat_info *info) +{ + struct ip_nat_multi_range mr; + u_int32_t newdstip, newsrcip, newip; + u_int16_t port; + struct ip_ct_h225_expect *exp_info; + struct ip_ct_h225_master *master_info; + struct ip_conntrack *master = master_ct(ct); + unsigned int is_h225, ret; + + IP_NF_ASSERT(info); + IP_NF_ASSERT(master); + + IP_NF_ASSERT(!(info->initialized & (1<master->expectant->help.ct_h225_info; + exp_info = &ct->master->help.exp_h225_info; + + LOCK_BH(&ip_h323_lock); + + DEBUGP("master: "); + DUMP_TUPLE(&master->tuplehash[IP_CT_DIR_ORIGINAL].tuple); + DUMP_TUPLE(&master->tuplehash[IP_CT_DIR_REPLY].tuple); + DEBUGP("conntrack: "); + DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); + if (exp_info->dir == IP_CT_DIR_ORIGINAL) { + /* Make connection go to the client. */ + newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; + newsrcip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; + DEBUGP("h225_nat_expected: %u.%u.%u.%u->%u.%u.%u.%u (to client)\n", + NIPQUAD(newsrcip), NIPQUAD(newdstip)); + } else { + /* Make the connection go to the server */ + newdstip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip; + newsrcip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; + DEBUGP("h225_nat_expected: %u.%u.%u.%u->%u.%u.%u.%u (to server)\n", + NIPQUAD(newsrcip), NIPQUAD(newdstip)); + } + port = exp_info->port; + is_h225 = master_info->is_h225 == H225_PORT; + UNLOCK_BH(&ip_h323_lock); + + if (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) + newip = newsrcip; + else + newip = newdstip; + + DEBUGP("h225_nat_expected: IP to %u.%u.%u.%u\n", NIPQUAD(newip)); + + mr.rangesize = 1; + /* We don't want to manip the per-protocol, just the IPs... */ + mr.range[0].flags = IP_NAT_RANGE_MAP_IPS; + mr.range[0].min_ip = mr.range[0].max_ip = newip; + + /* ... unless we're doing a MANIP_DST, in which case, make + sure we map to the correct port */ + if (HOOK2MANIP(hooknum) == IP_NAT_MANIP_DST) { + mr.range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED; + mr.range[0].min = mr.range[0].max + = ((union ip_conntrack_manip_proto) + { port }); + } + + ret = ip_nat_setup_info(ct, &mr, hooknum); + + if (is_h225) { + DEBUGP("h225_nat_expected: H.225, setting NAT helper for %p\n", ct); + /* NAT expectfn called with ip_nat_lock write-locked */ + info->helper = &h245; + } + return ret; +} + +static int h323_signal_address_fixup(struct ip_conntrack *ct, + struct sk_buff **pskb, + enum ip_conntrack_info ctinfo) +{ + struct iphdr *iph = (*pskb)->nh.iph; + struct tcphdr *tcph = (void *)iph + iph->ihl*4; + unsigned char *data; + u_int32_t tcplen = (*pskb)->len - iph->ihl*4; + u_int32_t datalen = tcplen - tcph->doff*4; + struct ip_ct_h225_master *info = &ct->help.ct_h225_info; + u_int32_t newip; + u_int16_t port; + u_int8_t buffer[6]; + int i; + + MUST_BE_LOCKED(&ip_h323_lock); + + DEBUGP("h323_signal_address_fixup: %s %s\n", + between(info->seq[IP_CT_DIR_ORIGINAL], ntohl(tcph->seq), ntohl(tcph->seq) + datalen) + ? "yes" : "no", + between(info->seq[IP_CT_DIR_REPLY], ntohl(tcph->seq), ntohl(tcph->seq) + datalen) + ? "yes" : "no"); + if (!(between(info->seq[IP_CT_DIR_ORIGINAL], ntohl(tcph->seq), ntohl(tcph->seq) + datalen) + || between(info->seq[IP_CT_DIR_REPLY], ntohl(tcph->seq), ntohl(tcph->seq) + datalen))) + return 1; + + DEBUGP("h323_signal_address_fixup: offsets %u + 6 and %u + 6 in %u\n", + info->offset[IP_CT_DIR_ORIGINAL], + info->offset[IP_CT_DIR_REPLY], + tcplen); + DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); + DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); + + for (i = 0; i < IP_CT_DIR_MAX; i++) { + DEBUGP("h323_signal_address_fixup: %s %s\n", + info->dir == IP_CT_DIR_ORIGINAL ? "original" : "reply", + i == IP_CT_DIR_ORIGINAL ? "caller" : "callee"); + if (!between(info->seq[i], ntohl(tcph->seq), + ntohl(tcph->seq) + datalen)) + continue; + if (!between(info->seq[i] + 6, ntohl(tcph->seq), + ntohl(tcph->seq) + datalen)) { + /* Partial retransmisison. It's a cracker being funky. */ + if (net_ratelimit()) { + printk("H.323_NAT: partial packet %u/6 in %u/%u\n", + info->seq[i], + ntohl(tcph->seq), + ntohl(tcph->seq) + datalen); + } + return 0; + } + + /* Change address inside packet to match way we're mapping + this connection. */ + if (i == IP_CT_DIR_ORIGINAL) { + newip = ct->tuplehash[!info->dir].tuple.dst.ip; + port = ct->tuplehash[!info->dir].tuple.dst.u.tcp.port; + } else { + newip = ct->tuplehash[!info->dir].tuple.src.ip; + port = ct->tuplehash[!info->dir].tuple.src.u.tcp.port; + } + + data = (char *) tcph + tcph->doff * 4 + info->offset[i]; + + DEBUGP("h323_signal_address_fixup: orig %s IP:port %u.%u.%u.%u:%u\n", + i == IP_CT_DIR_ORIGINAL ? "source" : "dest ", + data[0], data[1], data[2], data[3], + (data[4] << 8 | data[5])); + + /* Modify the packet */ + memcpy(buffer, &newip, 4); + memcpy(buffer + 4, &port, 2); + if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, info->offset[i], + 6, buffer, 6)) + return 0; + + DEBUGP("h323_signal_address_fixup: new %s IP:port %u.%u.%u.%u:%u\n", + i == IP_CT_DIR_ORIGINAL ? "source" : "dest ", + data[0], data[1], data[2], data[3], + (data[4] << 8 | data[5])); + } + + return 1; +} + +static int h323_data_fixup(struct ip_ct_h225_expect *info, + struct ip_conntrack *ct, + struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + struct ip_conntrack_expect *expect) +{ + u_int32_t newip; + u_int16_t port; + u_int8_t buffer[6]; + struct ip_conntrack_tuple newtuple; + struct iphdr *iph = (*pskb)->nh.iph; + struct tcphdr *tcph = (void *)iph + iph->ihl*4; + unsigned char *data; + u_int32_t tcplen = (*pskb)->len - iph->ihl*4; + struct ip_ct_h225_master *master_info = &ct->help.ct_h225_info; + int is_h225; + + MUST_BE_LOCKED(&ip_h323_lock); + DEBUGP("h323_data_fixup: offset %u + 6 in %u\n", info->offset, tcplen); + DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); + DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); + + if (!between(expect->seq + 6, ntohl(tcph->seq), + ntohl(tcph->seq) + tcplen - tcph->doff * 4)) { + /* Partial retransmisison. It's a cracker being funky. */ + if (net_ratelimit()) { + printk("H.323_NAT: partial packet %u/6 in %u/%u\n", + expect->seq, + ntohl(tcph->seq), + ntohl(tcph->seq) + tcplen - tcph->doff * 4); + } + return 0; + } + + /* Change address inside packet to match way we're mapping + this connection. */ + if (info->dir == IP_CT_DIR_REPLY) { + /* Must be where client thinks server is */ + newip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; + /* Expect something from client->server */ + newtuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; + newtuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; + } else { + /* Must be where server thinks client is */ + newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; + /* Expect something from server->client */ + newtuple.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip; + newtuple.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; + } + + is_h225 = (master_info->is_h225 == H225_PORT); + + if (is_h225) { + newtuple.dst.protonum = IPPROTO_TCP; + newtuple.src.u.tcp.port = expect->tuple.src.u.tcp.port; + } else { + newtuple.dst.protonum = IPPROTO_UDP; + newtuple.src.u.udp.port = expect->tuple.src.u.udp.port; + } + + /* Try to get same port: if not, try to change it. */ + for (port = ntohs(info->port); port != 0; port++) { + if (is_h225) + newtuple.dst.u.tcp.port = htons(port); + else + newtuple.dst.u.udp.port = htons(port); + + if (ip_conntrack_change_expect(expect, &newtuple) == 0) + break; + } + if (port == 0) { + DEBUGP("h323_data_fixup: no free port found!\n"); + return 0; + } + + port = htons(port); + + data = (char *) tcph + tcph->doff * 4 + info->offset; + + DEBUGP("h323_data_fixup: orig IP:port %u.%u.%u.%u:%u\n", + data[0], data[1], data[2], data[3], + (data[4] << 8 | data[5])); + + /* Modify the packet */ + memcpy(buffer, &newip, 4); + memcpy(buffer + 4, &port, 2); + if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, info->offset, + 6, buffer, 6)) + return 0; + + DEBUGP("h323_data_fixup: new IP:port %u.%u.%u.%u:%u\n", + data[0], data[1], data[2], data[3], + (data[4] << 8 | data[5])); + + return 1; +} + +static unsigned int h225_nat_help(struct ip_conntrack *ct, + struct ip_conntrack_expect *exp, + struct ip_nat_info *info, + enum ip_conntrack_info ctinfo, + unsigned int hooknum, + struct sk_buff **pskb) +{ + int dir; + struct ip_ct_h225_expect *exp_info; + + /* Only mangle things once: original direction in POST_ROUTING + and reply direction on PRE_ROUTING. */ + dir = CTINFO2DIR(ctinfo); + DEBUGP("nat_h323: dir %s at hook %s\n", + dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY", + hooknum == NF_IP_POST_ROUTING ? "POSTROUTING" + : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING" + : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT" : "???"); + if (!((hooknum == NF_IP_POST_ROUTING && dir == IP_CT_DIR_ORIGINAL) + || (hooknum == NF_IP_PRE_ROUTING && dir == IP_CT_DIR_REPLY))) { + DEBUGP("nat_h323: Not touching dir %s at hook %s\n", + dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY", + hooknum == NF_IP_POST_ROUTING ? "POSTROUTING" + : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING" + : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT" : "???"); + return NF_ACCEPT; + } + + if (!exp) { + LOCK_BH(&ip_h323_lock); + if (!h323_signal_address_fixup(ct, pskb, ctinfo)) { + UNLOCK_BH(&ip_h323_lock); + return NF_DROP; + } + UNLOCK_BH(&ip_h323_lock); + return NF_ACCEPT; + } + + exp_info = &exp->help.exp_h225_info; + + LOCK_BH(&ip_h323_lock); + if (!h323_data_fixup(exp_info, ct, pskb, ctinfo, exp)) { + UNLOCK_BH(&ip_h323_lock); + return NF_DROP; + } + UNLOCK_BH(&ip_h323_lock); + + return NF_ACCEPT; +} + +static struct ip_nat_helper h225 = + { { NULL, NULL }, + "H.225", /* name */ + IP_NAT_HELPER_F_ALWAYS, /* flags */ + THIS_MODULE, /* module */ + { { 0, { __constant_htons(H225_PORT) } }, /* tuple */ + { 0, { 0 }, IPPROTO_TCP } }, + { { 0, { 0xFFFF } }, /* mask */ + { 0, { 0 }, 0xFFFF } }, + h225_nat_help, /* helper */ + h225_nat_expected /* expectfn */ + }; + +static int __init init(void) +{ + int ret; + + ret = ip_nat_helper_register(&h225); + + if (ret != 0) + printk("ip_nat_h323: cannot initialize the module!\n"); + + return ret; +} + +static void __exit fini(void) +{ + ip_nat_helper_unregister(&h225); +} + +module_init(init); +module_exit(fini); diff -urN linux-2.4.32/include/linux/netfilter_ipv4/ip_conntrack.h linux-2.4.32.new/include/linux/netfilter_ipv4/ip_conntrack.h --- linux-2.4.32/include/linux/netfilter_ipv4/ip_conntrack.h 2006-03-01 00:49:36.474532856 +0100 +++ linux-2.4.32.new/include/linux/netfilter_ipv4/ip_conntrack.h 2006-03-01 00:50:18.699113744 +0100 @@ -71,6 +71,7 @@ #include #include #include +#include /* per expectation: application helper private data */ union ip_conntrack_expect_help { @@ -79,6 +80,7 @@ struct ip_ct_ftp_expect exp_ftp_info; struct ip_ct_irc_expect exp_irc_info; struct ip_ct_pptp_expect exp_pptp_info; + struct ip_ct_h225_expect exp_h225_info; #ifdef CONFIG_IP_NF_NAT_NEEDED union { @@ -93,6 +95,7 @@ struct ip_ct_ftp_master ct_ftp_info; struct ip_ct_irc_master ct_irc_info; struct ip_ct_pptp_master ct_pptp_info; + struct ip_ct_h225_master ct_h225_info; }; #ifdef CONFIG_IP_NF_NAT_NEEDED diff -urN linux-2.4.32/include/linux/netfilter_ipv4/ip_conntrack_h323.h linux-2.4.32.new/include/linux/netfilter_ipv4/ip_conntrack_h323.h --- linux-2.4.32/include/linux/netfilter_ipv4/ip_conntrack_h323.h 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.4.32.new/include/linux/netfilter_ipv4/ip_conntrack_h323.h 2006-03-01 00:50:18.700113592 +0100 @@ -0,0 +1,30 @@ +#ifndef _IP_CONNTRACK_H323_H +#define _IP_CONNTRACK_H323_H +/* H.323 connection tracking. */ + +#ifdef __KERNEL__ +/* Protects H.323 related data */ +DECLARE_LOCK_EXTERN(ip_h323_lock); +#endif + +/* Default H.225 port */ +#define H225_PORT 1720 + +/* This structure is per expected connection */ +struct ip_ct_h225_expect { + u_int16_t port; /* Port of the H.225 helper/RTCP/RTP channel */ + enum ip_conntrack_dir dir; /* Direction of the original connection */ + unsigned int offset; /* offset of the address in the payload */ +}; + +/* This structure exists only once per master */ +struct ip_ct_h225_master { + int is_h225; /* H.225 or H.245 connection */ +#ifdef CONFIG_IP_NF_NAT_NEEDED + enum ip_conntrack_dir dir; /* Direction of the original connection */ + u_int32_t seq[IP_CT_DIR_MAX]; /* Exceptional packet mangling for signal addressess... */ + unsigned int offset[IP_CT_DIR_MAX]; /* ...and the offset of the addresses in the payload */ +#endif +}; + +#endif /* _IP_CONNTRACK_H323_H */