From c0d4cfd96dd0cc0dbf49435898808b5553af4822 Mon Sep 17 00:00:00 2001 From: Jing Min Zhao Date: Mon, 29 May 2006 18:26:27 -0700 Subject: [PATCH] [NETFILTER]: H.323 helper: Add support for Call Forwarding Signed-off-by: Jing Min Zhao Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/netfilter_ipv4/ip_conntrack.h | 1 + .../linux/netfilter_ipv4/ip_conntrack_h323.h | 7 ++ .../ip_conntrack_helper_h323_types.h | 3 +- net/ipv4/netfilter/Kconfig | 8 +- net/ipv4/netfilter/ip_conntrack_helper_h323.c | 112 ++++++++++++++++++ .../ip_conntrack_helper_h323_types.c | 6 +- net/ipv4/netfilter/ip_nat_helper_h323.c | 77 ++++++++++++ 7 files changed, 206 insertions(+), 8 deletions(-) diff --git a/include/linux/netfilter_ipv4/ip_conntrack.h b/include/linux/netfilter_ipv4/ip_conntrack.h index 5473c01f69ea..17d7ef938a09 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack.h +++ b/include/linux/netfilter_ipv4/ip_conntrack.h @@ -154,6 +154,7 @@ struct ip_conntrack_expect unsigned int flags; #ifdef CONFIG_IP_NF_NAT_NEEDED + u_int32_t saved_ip; /* This is the original per-proto part, used to map the * expected connection the way the recipient expects. */ union ip_conntrack_manip_proto saved_proto; diff --git a/include/linux/netfilter_ipv4/ip_conntrack_h323.h b/include/linux/netfilter_ipv4/ip_conntrack_h323.h index eace86bd2adb..3cbff7379002 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack_h323.h +++ b/include/linux/netfilter_ipv4/ip_conntrack_h323.h @@ -71,6 +71,13 @@ extern int (*nat_h245_hook) (struct sk_buff ** pskb, struct ip_conntrack * ct, unsigned char **data, int dataoff, TransportAddress * addr, u_int16_t port, struct ip_conntrack_expect * exp); +extern int (*nat_callforwarding_hook) (struct sk_buff ** pskb, + struct ip_conntrack * ct, + enum ip_conntrack_info ctinfo, + unsigned char **data, int dataoff, + TransportAddress * addr, + u_int16_t port, + struct ip_conntrack_expect * exp); extern int (*nat_q931_hook) (struct sk_buff ** pskb, struct ip_conntrack * ct, enum ip_conntrack_info ctinfo, unsigned char **data, TransportAddress * addr, diff --git a/include/linux/netfilter_ipv4/ip_conntrack_helper_h323_types.h b/include/linux/netfilter_ipv4/ip_conntrack_helper_h323_types.h index cc98f7aa5abe..3d4a773799fc 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack_helper_h323_types.h +++ b/include/linux/netfilter_ipv4/ip_conntrack_helper_h323_types.h @@ -1,4 +1,4 @@ -/* Generated by Jing Min Zhao's ASN.1 parser, Mar 15 2006 +/* Generated by Jing Min Zhao's ASN.1 parser, Apr 20 2006 * * Copyright (c) 2006 Jing Min Zhao * @@ -412,6 +412,7 @@ typedef struct Facility_UUIE { /* SEQUENCE */ eFacility_UUIE_destinationInfo = (1 << 14), eFacility_UUIE_h245SecurityMode = (1 << 13), } options; + TransportAddress alternativeAddress; FacilityReason reason; TransportAddress h245Address; Facility_UUIE_fastStart fastStart; diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index 1540e227890f..f86aeda3a5a0 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -183,10 +183,10 @@ config IP_NF_H323 With this module you can support H.323 on a connection tracking/NAT firewall. - This module supports RAS, Fast-start, H.245 tunnelling, RTP/RTCP - and T.120 based data and applications including audio, video, FAX, - chat, whiteboard, file transfer, etc. For more information, please - see http://nath323.sourceforge.net/. + This module supports RAS, Fast Start, H.245 Tunnelling, Call + Forwarding, RTP/RTCP and T.120 based audio, video, fax, chat, + whiteboard, file transfer, etc. For more information, please + visit http://nath323.sourceforge.net/. If you want to compile it as a module, say 'M' here and read Documentation/modules.txt. If unsure, say 'N'. diff --git a/net/ipv4/netfilter/ip_conntrack_helper_h323.c b/net/ipv4/netfilter/ip_conntrack_helper_h323.c index 518f581d39ec..3052468a6ab1 100644 --- a/net/ipv4/netfilter/ip_conntrack_helper_h323.c +++ b/net/ipv4/netfilter/ip_conntrack_helper_h323.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #if 0 #define DEBUGP printk @@ -38,6 +40,13 @@ static int gkrouted_only = 1; module_param(gkrouted_only, int, 0600); MODULE_PARM_DESC(gkrouted_only, "only accept calls from gatekeeper"); +static char *internal_net = NULL; +static u_int32_t internal_net_addr = 0; +static u_int32_t internal_net_mask = 0; +module_param(internal_net, charp, 0600); +MODULE_PARM_DESC(internal_net, "specify your internal network using format " + "address/mask. this is used by call forwarding support"); + /* Hooks for NAT */ int (*set_h245_addr_hook) (struct sk_buff ** pskb, unsigned char **data, int dataoff, @@ -77,6 +86,12 @@ int (*nat_h245_hook) (struct sk_buff ** pskb, unsigned char **data, int dataoff, TransportAddress * addr, u_int16_t port, struct ip_conntrack_expect * exp); +int (*nat_callforwarding_hook) (struct sk_buff ** pskb, + struct ip_conntrack * ct, + enum ip_conntrack_info ctinfo, + unsigned char **data, int dataoff, + TransportAddress * addr, u_int16_t port, + struct ip_conntrack_expect * exp); int (*nat_q931_hook) (struct sk_buff ** pskb, struct ip_conntrack * ct, enum ip_conntrack_info ctinfo, @@ -683,6 +698,76 @@ static int expect_h245(struct sk_buff **pskb, struct ip_conntrack *ct, return ret; } +/* Forwarding declaration */ +void ip_conntrack_q931_expect(struct ip_conntrack *new, + struct ip_conntrack_expect *this); + +/****************************************************************************/ +static int expect_callforwarding(struct sk_buff **pskb, + struct ip_conntrack *ct, + enum ip_conntrack_info ctinfo, + unsigned char **data, int dataoff, + TransportAddress * addr) +{ + int dir = CTINFO2DIR(ctinfo); + int ret = 0; + u_int32_t ip; + u_int16_t port; + struct ip_conntrack_expect *exp = NULL; + + /* Read alternativeAddress */ + if (!get_h225_addr(*data, addr, &ip, &port) || port == 0) + return 0; + + /* If the calling party is on the same side of the forward-to party, + * we don't need to track the second call */ + if (internal_net && + ((ip & internal_net_mask) == internal_net_addr) == + ((ct->tuplehash[!dir].tuple.src.ip & internal_net_mask) == + internal_net_addr)) { + DEBUGP("ip_ct_q931: Call Forwarding not tracked\n"); + return 0; + } + + /* Create expect for the second call leg */ + if ((exp = ip_conntrack_expect_alloc(ct)) == NULL) + return -1; + exp->tuple.src.ip = ct->tuplehash[!dir].tuple.src.ip; + exp->tuple.src.u.tcp.port = 0; + exp->tuple.dst.ip = ip; + exp->tuple.dst.u.tcp.port = htons(port); + exp->tuple.dst.protonum = IPPROTO_TCP; + exp->mask.src.ip = 0xFFFFFFFF; + exp->mask.src.u.tcp.port = 0; + exp->mask.dst.ip = 0xFFFFFFFF; + exp->mask.dst.u.tcp.port = 0xFFFF; + exp->mask.dst.protonum = 0xFF; + exp->flags = 0; + + if (ct->tuplehash[dir].tuple.src.ip != + ct->tuplehash[!dir].tuple.dst.ip && nat_callforwarding_hook) { + /* Need NAT */ + ret = nat_callforwarding_hook(pskb, ct, ctinfo, data, dataoff, + addr, port, exp); + } else { /* Conntrack only */ + exp->expectfn = ip_conntrack_q931_expect; + + if (ip_conntrack_expect_related(exp) == 0) { + DEBUGP("ip_ct_q931: expect Call Forwarding " + "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", + NIPQUAD(exp->tuple.src.ip), + ntohs(exp->tuple.src.u.tcp.port), + NIPQUAD(exp->tuple.dst.ip), + ntohs(exp->tuple.dst.u.tcp.port)); + } else + ret = -1; + } + + ip_conntrack_expect_put(exp); + + return ret; +} + /****************************************************************************/ static int process_setup(struct sk_buff **pskb, struct ip_conntrack *ct, enum ip_conntrack_info ctinfo, @@ -878,6 +963,15 @@ static int process_facility(struct sk_buff **pskb, struct ip_conntrack *ct, DEBUGP("ip_ct_q931: Facility\n"); + if (facility->reason.choice == eFacilityReason_callForwarded) { + if (facility->options & eFacility_UUIE_alternativeAddress) + return expect_callforwarding(pskb, ct, ctinfo, data, + dataoff, + &facility-> + alternativeAddress); + return 0; + } + if (facility->options & eFacility_UUIE_h245Address) { ret = expect_h245(pskb, ct, ctinfo, data, dataoff, &facility->h245Address); @@ -1668,6 +1762,7 @@ static void fini(void) static int __init init(void) { int ret; + char *p; h323_buffer = kmalloc(65536, GFP_KERNEL); if (!h323_buffer) @@ -1678,6 +1773,22 @@ static int __init init(void) return ret; } + if (internal_net) { + if ((p = strchr(internal_net, '/'))) + *p++ = 0; + if (isdigit(internal_net[0])) { + internal_net_addr = in_aton(internal_net); + if (p && isdigit(p[0])) + internal_net_mask = in_aton(p); + else + internal_net_mask = 0xffffffff; + internal_net_addr &= internal_net_mask; + } + DEBUGP("ip_ct_h323: internal_net = %u.%u.%u.%u/%u.%u.%u.%u\n", + NIPQUAD(internal_net_addr), + NIPQUAD(internal_net_mask)); + } + DEBUGP("ip_ct_h323: init success\n"); return 0; } @@ -1696,6 +1807,7 @@ EXPORT_SYMBOL_GPL(set_ras_addr_hook); EXPORT_SYMBOL_GPL(nat_rtp_rtcp_hook); EXPORT_SYMBOL_GPL(nat_t120_hook); EXPORT_SYMBOL_GPL(nat_h245_hook); +EXPORT_SYMBOL_GPL(nat_callforwarding_hook); EXPORT_SYMBOL_GPL(nat_q931_hook); MODULE_AUTHOR("Jing Min Zhao "); diff --git a/net/ipv4/netfilter/ip_conntrack_helper_h323_types.c b/net/ipv4/netfilter/ip_conntrack_helper_h323_types.c index 022c47b9f6c9..4b359618bedd 100644 --- a/net/ipv4/netfilter/ip_conntrack_helper_h323_types.c +++ b/net/ipv4/netfilter/ip_conntrack_helper_h323_types.c @@ -1,4 +1,4 @@ -/* Generated by Jing Min Zhao's ASN.1 parser, Mar 15 2006 +/* Generated by Jing Min Zhao's ASN.1 parser, Apr 20 2006 * * Copyright (c) 2006 Jing Min Zhao * @@ -1069,8 +1069,8 @@ static field_t _Facility_UUIE_fastStart[] = { /* SEQUENCE OF */ static field_t _Facility_UUIE[] = { /* SEQUENCE */ {FNAME("protocolIdentifier") OID, BYTE, 0, 0, SKIP, 0, NULL}, - {FNAME("alternativeAddress") CHOICE, 3, 7, 7, SKIP | EXT | OPT, 0, - _TransportAddress}, + {FNAME("alternativeAddress") CHOICE, 3, 7, 7, DECODE | EXT | OPT, + offsetof(Facility_UUIE, alternativeAddress), _TransportAddress}, {FNAME("alternativeAliasAddress") SEQOF, SEMI, 0, 0, SKIP | OPT, 0, _Facility_UUIE_alternativeAliasAddress}, {FNAME("conferenceID") OCTSTR, FIXD, 16, 0, SKIP | OPT, 0, NULL}, diff --git a/net/ipv4/netfilter/ip_nat_helper_h323.c b/net/ipv4/netfilter/ip_nat_helper_h323.c index d45663d137a7..419b878fb467 100644 --- a/net/ipv4/netfilter/ip_nat_helper_h323.c +++ b/net/ipv4/netfilter/ip_nat_helper_h323.c @@ -486,6 +486,80 @@ static int nat_q931(struct sk_buff **pskb, struct ip_conntrack *ct, return 0; } +/****************************************************************************/ +static void ip_nat_callforwarding_expect(struct ip_conntrack *new, + struct ip_conntrack_expect *this) +{ + struct ip_nat_range range; + + /* This must be a fresh one. */ + BUG_ON(new->status & IPS_NAT_DONE_MASK); + + /* Change src to where master sends to */ + range.flags = IP_NAT_RANGE_MAP_IPS; + range.min_ip = range.max_ip = new->tuplehash[!this->dir].tuple.src.ip; + + /* hook doesn't matter, but it has to do source manip */ + ip_nat_setup_info(new, &range, NF_IP_POST_ROUTING); + + /* For DST manip, map port here to where it's expected. */ + range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED); + range.min = range.max = this->saved_proto; + range.min_ip = range.max_ip = this->saved_ip; + + /* hook doesn't matter, but it has to do destination manip */ + ip_nat_setup_info(new, &range, NF_IP_PRE_ROUTING); + + ip_conntrack_q931_expect(new, this); +} + +/****************************************************************************/ +static int nat_callforwarding(struct sk_buff **pskb, struct ip_conntrack *ct, + enum ip_conntrack_info ctinfo, + unsigned char **data, int dataoff, + TransportAddress * addr, u_int16_t port, + struct ip_conntrack_expect *exp) +{ + int dir = CTINFO2DIR(ctinfo); + u_int16_t nated_port; + + /* Set expectations for NAT */ + exp->saved_ip = exp->tuple.dst.ip; + exp->tuple.dst.ip = ct->tuplehash[!dir].tuple.dst.ip; + exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; + exp->expectfn = ip_nat_callforwarding_expect; + exp->dir = !dir; + + /* Try to get same port: if not, try to change it. */ + for (nated_port = port; nated_port != 0; nated_port++) { + exp->tuple.dst.u.tcp.port = htons(nated_port); + if (ip_conntrack_expect_related(exp) == 0) + break; + } + + if (nated_port == 0) { /* No port available */ + if (net_ratelimit()) + printk("ip_nat_q931: out of TCP ports\n"); + return 0; + } + + /* Modify signal */ + if (!set_h225_addr(pskb, data, dataoff, addr, + ct->tuplehash[!dir].tuple.dst.ip, + nated_port) == 0) { + ip_conntrack_unexpect_related(exp); + return -1; + } + + /* Success */ + DEBUGP("ip_nat_q931: expect Call Forwarding " + "%u.%u.%u.%u:%hu->%u.%u.%u.%u:%hu\n", + NIPQUAD(exp->tuple.src.ip), ntohs(exp->tuple.src.u.tcp.port), + NIPQUAD(exp->tuple.dst.ip), ntohs(exp->tuple.dst.u.tcp.port)); + + return 0; +} + /****************************************************************************/ static int __init init(void) { @@ -496,6 +570,7 @@ static int __init init(void) BUG_ON(nat_rtp_rtcp_hook != NULL); BUG_ON(nat_t120_hook != NULL); BUG_ON(nat_h245_hook != NULL); + BUG_ON(nat_callforwarding_hook != NULL); BUG_ON(nat_q931_hook != NULL); set_h245_addr_hook = set_h245_addr; @@ -505,6 +580,7 @@ static int __init init(void) nat_rtp_rtcp_hook = nat_rtp_rtcp; nat_t120_hook = nat_t120; nat_h245_hook = nat_h245; + nat_callforwarding_hook = nat_callforwarding; nat_q931_hook = nat_q931; DEBUGP("ip_nat_h323: init success\n"); @@ -521,6 +597,7 @@ static void __exit fini(void) nat_rtp_rtcp_hook = NULL; nat_t120_hook = NULL; nat_h245_hook = NULL; + nat_callforwarding_hook = NULL; nat_q931_hook = NULL; synchronize_net(); }