[NETFILTER]: nf_nat_sip: translate all Via headers

Update maddr=, received= and rport= Via-header parameters refering to
the signalling connection.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/nf_nat_sip.c

@@ -100,9 +100,11 @@ static unsigned int ip_nat_sip(struct sk_buff *skb,
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 	unsigned int matchoff, matchlen;
 	union nf_inet_addr addr;
 	__be16 port;
+	int request;
 
 	/* Basic rules: requests and responses. */
 	if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) {
@@ -112,11 +114,81 @@ static unsigned int ip_nat_sip(struct sk_buff *skb,
 		    !map_addr(skb, dptr, datalen, matchoff, matchlen,
 			      &addr, port))
 			return NF_DROP;
+		request = 1;
+	} else
+		request = 0;
+
+	/* Translate topmost Via header and parameters */
+	if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
+				    SIP_HDR_VIA, NULL, &matchoff, &matchlen,
+				    &addr, &port) > 0) {
+		unsigned int matchend, poff, plen, buflen, n;
+		char buffer[sizeof("nnn.nnn.nnn.nnn:nnnnn")];
+
+		/* We're only interested in headers related to this
+		 * connection */
+		if (request) {
+			if (addr.ip != ct->tuplehash[dir].tuple.src.u3.ip ||
+			    port != ct->tuplehash[dir].tuple.src.u.udp.port)
+				goto next;
+		} else {
+			if (addr.ip != ct->tuplehash[dir].tuple.dst.u3.ip ||
+			    port != ct->tuplehash[dir].tuple.dst.u.udp.port)
+				goto next;
+		}
+
+		if (!map_addr(skb, dptr, datalen, matchoff, matchlen,
+			      &addr, port))
+			return NF_DROP;
+
+		matchend = matchoff + matchlen;
+
+		/* 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) > 0 &&
+		    addr.ip == ct->tuplehash[dir].tuple.src.u3.ip &&
+		    addr.ip != ct->tuplehash[!dir].tuple.dst.u3.ip) {
+			__be32 ip = ct->tuplehash[!dir].tuple.dst.u3.ip;
+			buflen = sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
+			if (!mangle_packet(skb, 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) > 0 &&
+		    addr.ip == ct->tuplehash[dir].tuple.dst.u3.ip &&
+		    addr.ip != ct->tuplehash[!dir].tuple.src.u3.ip) {
+			__be32 ip = ct->tuplehash[!dir].tuple.src.u3.ip;
+			buflen = sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(ip));
+			if (!mangle_packet(skb, 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, dptr, datalen, poff, plen,
+					   buffer, buflen))
+				return NF_DROP;
+		}
 	}
 
+next:
 	if (!map_sip_addr(skb, dptr, datalen, SIP_HDR_FROM) ||
 	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_TO) ||
-	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_VIA) ||
 	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_CONTACT))
 		return NF_DROP;
 	return NF_ACCEPT;