[NETFILTER]: nf_conntrack_sip: create RTCP expectations

Create expectations for the RTCP connections in addition to RTP connections.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 16 deletions

diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index 4b85e21a2a4a..f73ab4883b75 100644
--- a/net/ipv4/netfilter/nf_nat_sip.c
+++ b/net/ipv4/netfilter/nf_nat_sip.c
@@ -364,7 +364,8 @@ static unsigned int mangle_sdp(struct sk_buff *skb,
    Mangle it, and change the expectation to match the new version. */
 static unsigned int ip_nat_sdp(struct sk_buff *skb,
                                const char **dptr, unsigned int *datalen,
-                               struct nf_conntrack_expect *exp)
+                               struct nf_conntrack_expect *rtp_exp,
+                               struct nf_conntrack_expect *rtcp_exp)
 {
         enum ip_conntrack_info ctinfo;
         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
@@ -375,31 +376,40 @@ static unsigned int ip_nat_sdp(struct sk_buff *skb,
         /* Connection will come from reply */
         if (ct->tuplehash[dir].tuple.src.u3.ip ==
             ct->tuplehash[!dir].tuple.dst.u3.ip)
-                newip = exp->tuple.dst.u3.ip;
+                newip = rtp_exp->tuple.dst.u3.ip;
         else
                 newip = ct->tuplehash[!dir].tuple.dst.u3.ip;
 
-        exp->saved_ip = exp->tuple.dst.u3.ip;
-        exp->tuple.dst.u3.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_sip_expected;
-
-        /* 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 (nf_ct_expect_related(exp) == 0)
+        rtp_exp->saved_ip = rtp_exp->tuple.dst.u3.ip;
+        rtp_exp->tuple.dst.u3.ip = newip;
+        rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
+        rtp_exp->dir = !dir;
+        rtp_exp->expectfn = ip_nat_sip_expected;
+
+        rtcp_exp->saved_ip = rtcp_exp->tuple.dst.u3.ip;
+        rtcp_exp->tuple.dst.u3.ip = newip;
+        rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
+        rtcp_exp->dir = !dir;
+        rtcp_exp->expectfn = ip_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) {
+                rtp_exp->tuple.dst.u.udp.port = htons(port);
+                if (nf_ct_expect_related(rtp_exp) != 0)
+                        continue;
+                rtcp_exp->tuple.dst.u.udp.port = htons(port + 1);
+                if (nf_ct_expect_related(rtcp_exp) == 0)
                         break;
+                nf_ct_unexpect_related(rtp_exp);
         }
 
         if (port == 0)
                 return NF_DROP;
 
         if (!mangle_sdp(skb, ctinfo, ct, newip, port, dptr, datalen)) {
-                nf_ct_unexpect_related(exp);
+                nf_ct_unexpect_related(rtp_exp);
+                nf_ct_unexpect_related(rtcp_exp);
                 return NF_DROP;
         }
         return NF_ACCEPT;