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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 13:38:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-02 13:38:27 -0700
commitaecdc33e111b2c447b622e287c6003726daa1426 (patch)
tree3e7657eae4b785e1a1fb5dfb225dbae0b2f0cfc6 /net/netfilter/nf_nat_sip.c
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next (diff)
parenthyperv: Add buffer for extended info after the RNDIS response message. (diff)
downloadlinux-dev-aecdc33e111b2c447b622e287c6003726daa1426.tar.xz
linux-dev-aecdc33e111b2c447b622e287c6003726daa1426.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking changes from David Miller: 1) GRE now works over ipv6, from Dmitry Kozlov. 2) Make SCTP more network namespace aware, from Eric Biederman. 3) TEAM driver now works with non-ethernet devices, from Jiri Pirko. 4) Make openvswitch network namespace aware, from Pravin B Shelar. 5) IPV6 NAT implementation, from Patrick McHardy. 6) Server side support for TCP Fast Open, from Jerry Chu and others. 7) Packet BPF filter supports MOD and XOR, from Eric Dumazet and Daniel Borkmann. 8) Increate the loopback default MTU to 64K, from Eric Dumazet. 9) Use a per-task rather than per-socket page fragment allocator for outgoing networking traffic. This benefits processes that have very many mostly idle sockets, which is quite common. From Eric Dumazet. 10) Use up to 32K for page fragment allocations, with fallbacks to smaller sizes when higher order page allocations fail. Benefits are a) less segments for driver to process b) less calls to page allocator c) less waste of space. From Eric Dumazet. 11) Allow GRO to be used on GRE tunnels, from Eric Dumazet. 12) VXLAN device driver, one way to handle VLAN issues such as the limitation of 4096 VLAN IDs yet still have some level of isolation. From Stephen Hemminger. 13) As usual there is a large boatload of driver changes, with the scale perhaps tilted towards the wireless side this time around. Fix up various fairly trivial conflicts, mostly caused by the user namespace changes. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1012 commits) hyperv: Add buffer for extended info after the RNDIS response message. hyperv: Report actual status in receive completion packet hyperv: Remove extra allocated space for recv_pkt_list elements hyperv: Fix page buffer handling in rndis_filter_send_request() hyperv: Fix the missing return value in rndis_filter_set_packet_filter() hyperv: Fix the max_xfer_size in RNDIS initialization vxlan: put UDP socket in correct namespace vxlan: Depend on CONFIG_INET sfc: Fix the reported priorities of different filter types sfc: Remove EFX_FILTER_FLAG_RX_OVERRIDE_IP sfc: Fix loopback self-test with separate_tx_channels=1 sfc: Fix MCDI structure field lookup sfc: Add parentheses around use of bitfield macro arguments sfc: Fix null function pointer in efx_sriov_channel_type vxlan: virtual extensible lan igmp: export symbol ip_mc_leave_group netlink: add attributes to fdb interface tg3: unconditionally select HWMON support when tg3 is enabled. Revert "net: ti cpsw ethernet: allow reading phy interface mode from DT" gre: fix sparse warning ...
Diffstat (limited to 'net/netfilter/nf_nat_sip.c')
-rw-r--r--net/netfilter/nf_nat_sip.c612
1 files changed, 612 insertions, 0 deletions
diff --git a/net/netfilter/nf_nat_sip.c b/net/netfilter/nf_nat_sip.c
new file mode 100644
index 000000000000..16303c752213
--- /dev/null
+++ b/net/netfilter/nf_nat_sip.c
@@ -0,0 +1,612 @@
+/* SIP extension for NAT alteration.
+ *
+ * (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
+ * based on RR's ip_nat_ftp.c and other modules.
+ * (C) 2007 United Security Providers
+ * (C) 2007, 2008, 2011, 2012 Patrick McHardy <kaber@trash.net>
+ *
+ * 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/inet.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_helper.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");
+
+
+static unsigned int mangle_packet(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int matchoff, unsigned int matchlen,
+ const char *buffer, unsigned int buflen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ struct tcphdr *th;
+ unsigned int baseoff;
+
+ if (nf_ct_protonum(ct) == IPPROTO_TCP) {
+ th = (struct tcphdr *)(skb->data + protoff);
+ baseoff = protoff + th->doff * 4;
+ matchoff += dataoff - baseoff;
+
+ if (!__nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+ protoff, matchoff, matchlen,
+ buffer, buflen, false))
+ return 0;
+ } else {
+ baseoff = protoff + sizeof(struct udphdr);
+ matchoff += dataoff - baseoff;
+
+ if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
+ protoff, matchoff, matchlen,
+ buffer, buflen))
+ return 0;
+ }
+
+ /* Reload data pointer and adjust datalen value */
+ *dptr = skb->data + dataoff;
+ *datalen += buflen - matchlen;
+ return 1;
+}
+
+static int sip_sprintf_addr(const struct nf_conn *ct, char *buffer,
+ const union nf_inet_addr *addr, bool delim)
+{
+ if (nf_ct_l3num(ct) == NFPROTO_IPV4)
+ return sprintf(buffer, "%pI4", &addr->ip);
+ else {
+ if (delim)
+ return sprintf(buffer, "[%pI6c]", &addr->ip6);
+ else
+ return sprintf(buffer, "%pI6c", &addr->ip6);
+ }
+}
+
+static int sip_sprintf_addr_port(const struct nf_conn *ct, char *buffer,
+ const union nf_inet_addr *addr, u16 port)
+{
+ if (nf_ct_l3num(ct) == NFPROTO_IPV4)
+ return sprintf(buffer, "%pI4:%u", &addr->ip, port);
+ else
+ return sprintf(buffer, "[%pI6c]:%u", &addr->ip6, port);
+}
+
+static int map_addr(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int matchoff, unsigned int matchlen,
+ union nf_inet_addr *addr, __be16 port)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
+ unsigned int buflen;
+ union nf_inet_addr newaddr;
+ __be16 newport;
+
+ if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, addr) &&
+ ct->tuplehash[dir].tuple.src.u.udp.port == port) {
+ newaddr = ct->tuplehash[!dir].tuple.dst.u3;
+ newport = ct->tuplehash[!dir].tuple.dst.u.udp.port;
+ } else if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, addr) &&
+ ct->tuplehash[dir].tuple.dst.u.udp.port == port) {
+ newaddr = ct->tuplehash[!dir].tuple.src.u3;
+ newport = ct->tuplehash[!dir].tuple.src.u.udp.port;
+ } else
+ return 1;
+
+ if (nf_inet_addr_cmp(&newaddr, addr) && newport == port)
+ return 1;
+
+ buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, ntohs(newport));
+ return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, buffer, buflen);
+}
+
+static int map_sip_addr(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ enum sip_header_types type)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchlen, matchoff;
+ union nf_inet_addr addr;
+ __be16 port;
+
+ if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL,
+ &matchoff, &matchlen, &addr, &port) <= 0)
+ return 1;
+ return map_addr(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, &addr, port);
+}
+
+static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ unsigned int coff, matchoff, matchlen;
+ enum sip_header_types hdr;
+ union nf_inet_addr addr;
+ __be16 port;
+ int request, in_header;
+
+ /* Basic rules: requests and responses. */
+ if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) {
+ if (ct_sip_parse_request(ct, *dptr, *datalen,
+ &matchoff, &matchlen,
+ &addr, &port) > 0 &&
+ !map_addr(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, &addr, port))
+ return NF_DROP;
+ request = 1;
+ } else
+ request = 0;
+
+ if (nf_ct_protonum(ct) == IPPROTO_TCP)
+ hdr = SIP_HDR_VIA_TCP;
+ else
+ hdr = SIP_HDR_VIA_UDP;
+
+ /* Translate topmost Via header and parameters */
+ if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
+ hdr, NULL, &matchoff, &matchlen,
+ &addr, &port) > 0) {
+ unsigned int olen, matchend, poff, plen, buflen, n;
+ char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
+
+ /* We're only interested in headers related to this
+ * connection */
+ if (request) {
+ if (!nf_inet_addr_cmp(&addr,
+ &ct->tuplehash[dir].tuple.src.u3) ||
+ port != ct->tuplehash[dir].tuple.src.u.udp.port)
+ goto next;
+ } else {
+ if (!nf_inet_addr_cmp(&addr,
+ &ct->tuplehash[dir].tuple.dst.u3) ||
+ port != ct->tuplehash[dir].tuple.dst.u.udp.port)
+ goto next;
+ }
+
+ olen = *datalen;
+ if (!map_addr(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, &addr, port))
+ return NF_DROP;
+
+ matchend = matchoff + matchlen + *datalen - olen;
+
+ /* The maddr= parameter (RFC 2361) specifies where to send
+ * the reply. */
+ if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen,
+ "maddr=", &poff, &plen,
+ &addr, true) > 0 &&
+ nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3) &&
+ !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3)) {
+ buflen = sip_sprintf_addr(ct, buffer,
+ &ct->tuplehash[!dir].tuple.dst.u3,
+ true);
+ if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ poff, plen, buffer, buflen))
+ return NF_DROP;
+ }
+
+ /* The received= parameter (RFC 2361) contains the address
+ * from which the server received the request. */
+ if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen,
+ "received=", &poff, &plen,
+ &addr, false) > 0 &&
+ nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.dst.u3) &&
+ !nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.src.u3)) {
+ buflen = sip_sprintf_addr(ct, buffer,
+ &ct->tuplehash[!dir].tuple.src.u3,
+ false);
+ if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ poff, plen, buffer, buflen))
+ return NF_DROP;
+ }
+
+ /* The rport= parameter (RFC 3581) contains the port number
+ * from which the server received the request. */
+ if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen,
+ "rport=", &poff, &plen,
+ &n) > 0 &&
+ htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port &&
+ htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) {
+ __be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port;
+ buflen = sprintf(buffer, "%u", ntohs(p));
+ if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ poff, plen, buffer, buflen))
+ return NF_DROP;
+ }
+ }
+
+next:
+ /* Translate Contact headers */
+ coff = 0;
+ in_header = 0;
+ while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen,
+ SIP_HDR_CONTACT, &in_header,
+ &matchoff, &matchlen,
+ &addr, &port) > 0) {
+ if (!map_addr(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen,
+ &addr, port))
+ return NF_DROP;
+ }
+
+ if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) ||
+ !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO))
+ return NF_DROP;
+
+ return NF_ACCEPT;
+}
+
+static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff,
+ s16 off)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ const struct tcphdr *th;
+
+ if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0)
+ return;
+
+ th = (struct tcphdr *)(skb->data + protoff);
+ nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off);
+}
+
+/* Handles expected signalling connections and media streams */
+static void nf_nat_sip_expected(struct nf_conn *ct,
+ struct nf_conntrack_expect *exp)
+{
+ struct nf_nat_range range;
+
+ /* This must be a fresh one. */
+ BUG_ON(ct->status & IPS_NAT_DONE_MASK);
+
+ /* For DST manip, map port here to where it's expected. */
+ range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
+ range.min_proto = range.max_proto = exp->saved_proto;
+ range.min_addr = range.max_addr = exp->saved_addr;
+ nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
+
+ /* Change src to where master sends to, but only if the connection
+ * actually came from the same source. */
+ if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
+ &ct->master->tuplehash[exp->dir].tuple.src.u3)) {
+ range.flags = NF_NAT_RANGE_MAP_IPS;
+ range.min_addr = range.max_addr
+ = ct->master->tuplehash[!exp->dir].tuple.dst.u3;
+ nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
+ }
+}
+
+static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ struct nf_conntrack_expect *exp,
+ unsigned int matchoff,
+ unsigned int matchlen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ union nf_inet_addr newaddr;
+ u_int16_t port;
+ char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
+ unsigned int buflen;
+
+ /* Connection will come from reply */
+ if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
+ &ct->tuplehash[!dir].tuple.dst.u3))
+ newaddr = exp->tuple.dst.u3;
+ else
+ newaddr = ct->tuplehash[!dir].tuple.dst.u3;
+
+ /* If the signalling port matches the connection's source port in the
+ * original direction, try to use the destination port in the opposite
+ * direction. */
+ if (exp->tuple.dst.u.udp.port ==
+ ct->tuplehash[dir].tuple.src.u.udp.port)
+ port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port);
+ else
+ port = ntohs(exp->tuple.dst.u.udp.port);
+
+ exp->saved_addr = exp->tuple.dst.u3;
+ exp->tuple.dst.u3 = newaddr;
+ exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port;
+ exp->dir = !dir;
+ exp->expectfn = nf_nat_sip_expected;
+
+ for (; port != 0; port++) {
+ int ret;
+
+ exp->tuple.dst.u.udp.port = htons(port);
+ ret = nf_ct_expect_related(exp);
+ if (ret == 0)
+ break;
+ else if (ret != -EBUSY) {
+ port = 0;
+ break;
+ }
+ }
+
+ if (port == 0)
+ return NF_DROP;
+
+ if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) ||
+ exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) {
+ buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port);
+ if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, buffer, buflen))
+ goto err;
+ }
+ return NF_ACCEPT;
+
+err:
+ nf_ct_unexpect_related(exp);
+ return NF_DROP;
+}
+
+static int mangle_content_len(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchoff, matchlen;
+ char buffer[sizeof("65536")];
+ int buflen, c_len;
+
+ /* Get actual SDP length */
+ if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
+ SDP_HDR_VERSION, SDP_HDR_UNSPEC,
+ &matchoff, &matchlen) <= 0)
+ return 0;
+ c_len = *datalen - matchoff + strlen("v=");
+
+ /* Now, update SDP length */
+ if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH,
+ &matchoff, &matchlen) <= 0)
+ return 0;
+
+ buflen = sprintf(buffer, "%u", c_len);
+ return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, buffer, buflen);
+}
+
+static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int sdpoff,
+ enum sdp_header_types type,
+ enum sdp_header_types term,
+ char *buffer, int buflen)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ unsigned int matchlen, matchoff;
+
+ if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term,
+ &matchoff, &matchlen) <= 0)
+ return -ENOENT;
+ return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL;
+}
+
+static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int sdpoff,
+ enum sdp_header_types type,
+ enum sdp_header_types term,
+ const union nf_inet_addr *addr)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ char buffer[INET6_ADDRSTRLEN];
+ unsigned int buflen;
+
+ buflen = sip_sprintf_addr(ct, buffer, addr, false);
+ if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen,
+ sdpoff, type, term, buffer, buflen))
+ return 0;
+
+ return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
+}
+
+static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int matchoff,
+ unsigned int matchlen,
+ u_int16_t port)
+{
+ char buffer[sizeof("nnnnn")];
+ unsigned int buflen;
+
+ buflen = sprintf(buffer, "%u", port);
+ if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+ matchoff, matchlen, buffer, buflen))
+ return 0;
+
+ return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
+}
+
+static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ unsigned int sdpoff,
+ const union nf_inet_addr *addr)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ char buffer[INET6_ADDRSTRLEN];
+ unsigned int buflen;
+
+ /* Mangle session description owner and contact addresses */
+ buflen = sip_sprintf_addr(ct, buffer, addr, false);
+ if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
+ SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen))
+ return 0;
+
+ switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
+ SDP_HDR_CONNECTION, SDP_HDR_MEDIA,
+ buffer, buflen)) {
+ case 0:
+ /*
+ * RFC 2327:
+ *
+ * Session description
+ *
+ * c=* (connection information - not required if included in all media)
+ */
+ case -ENOENT:
+ break;
+ default:
+ return 0;
+ }
+
+ return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
+}
+
+/* So, this packet has hit the connection tracking matching code.
+ Mangle it, and change the expectation to match the new version. */
+static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff,
+ unsigned int dataoff,
+ const char **dptr, unsigned int *datalen,
+ struct nf_conntrack_expect *rtp_exp,
+ struct nf_conntrack_expect *rtcp_exp,
+ unsigned int mediaoff,
+ unsigned int medialen,
+ union nf_inet_addr *rtp_addr)
+{
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ u_int16_t port;
+
+ /* Connection will come from reply */
+ if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
+ &ct->tuplehash[!dir].tuple.dst.u3))
+ *rtp_addr = rtp_exp->tuple.dst.u3;
+ else
+ *rtp_addr = ct->tuplehash[!dir].tuple.dst.u3;
+
+ rtp_exp->saved_addr = rtp_exp->tuple.dst.u3;
+ rtp_exp->tuple.dst.u3 = *rtp_addr;
+ rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
+ rtp_exp->dir = !dir;
+ rtp_exp->expectfn = nf_nat_sip_expected;
+
+ rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3;
+ rtcp_exp->tuple.dst.u3 = *rtp_addr;
+ rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
+ rtcp_exp->dir = !dir;
+ rtcp_exp->expectfn = nf_nat_sip_expected;
+
+ /* Try to get same pair of ports: if not, try to change them. */
+ for (port = ntohs(rtp_exp->tuple.dst.u.udp.port);
+ port != 0; port += 2) {
+ int ret;
+
+ rtp_exp->tuple.dst.u.udp.port = htons(port);
+ ret = nf_ct_expect_related(rtp_exp);
+ if (ret == -EBUSY)
+ continue;
+ else if (ret < 0) {
+ port = 0;
+ break;
+ }
+ rtcp_exp->tuple.dst.u.udp.port = htons(port + 1);
+ ret = nf_ct_expect_related(rtcp_exp);
+ if (ret == 0)
+ break;
+ else if (ret == -EBUSY) {
+ nf_ct_unexpect_related(rtp_exp);
+ continue;
+ } else if (ret < 0) {
+ nf_ct_unexpect_related(rtp_exp);
+ port = 0;
+ break;
+ }
+ }
+
+ if (port == 0)
+ goto err1;
+
+ /* Update media port. */
+ if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port &&
+ !nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen,
+ mediaoff, medialen, port))
+ goto err2;
+
+ return NF_ACCEPT;
+
+err2:
+ nf_ct_unexpect_related(rtp_exp);
+ nf_ct_unexpect_related(rtcp_exp);
+err1:
+ return NF_DROP;
+}
+
+static struct nf_ct_helper_expectfn sip_nat = {
+ .name = "sip",
+ .expectfn = nf_nat_sip_expected,
+};
+
+static void __exit nf_nat_sip_fini(void)
+{
+ RCU_INIT_POINTER(nf_nat_sip_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sip_expect_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sdp_addr_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sdp_port_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sdp_session_hook, NULL);
+ RCU_INIT_POINTER(nf_nat_sdp_media_hook, NULL);
+ nf_ct_helper_expectfn_unregister(&sip_nat);
+ synchronize_rcu();
+}
+
+static int __init nf_nat_sip_init(void)
+{
+ BUG_ON(nf_nat_sip_hook != NULL);
+ BUG_ON(nf_nat_sip_seq_adjust_hook != NULL);
+ BUG_ON(nf_nat_sip_expect_hook != NULL);
+ BUG_ON(nf_nat_sdp_addr_hook != NULL);
+ BUG_ON(nf_nat_sdp_port_hook != NULL);
+ BUG_ON(nf_nat_sdp_session_hook != NULL);
+ BUG_ON(nf_nat_sdp_media_hook != NULL);
+ RCU_INIT_POINTER(nf_nat_sip_hook, nf_nat_sip);
+ RCU_INIT_POINTER(nf_nat_sip_seq_adjust_hook, nf_nat_sip_seq_adjust);
+ RCU_INIT_POINTER(nf_nat_sip_expect_hook, nf_nat_sip_expect);
+ RCU_INIT_POINTER(nf_nat_sdp_addr_hook, nf_nat_sdp_addr);
+ RCU_INIT_POINTER(nf_nat_sdp_port_hook, nf_nat_sdp_port);
+ RCU_INIT_POINTER(nf_nat_sdp_session_hook, nf_nat_sdp_session);
+ RCU_INIT_POINTER(nf_nat_sdp_media_hook, nf_nat_sdp_media);
+ nf_ct_helper_expectfn_register(&sip_nat);
+ return 0;
+}
+
+module_init(nf_nat_sip_init);
+module_exit(nf_nat_sip_fini);