[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>

diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h
index 7cc84ed..6ddf95f 100644 (file)
--- a/include/linux/netfilter/nf_conntrack_sip.h
+++ b/include/linux/netfilter/nf_conntrack_sip.h
@@ -96,7 +96,8 @@ extern unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb,
 extern unsigned int (*nf_nat_sdp_hook)(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);
 
 extern int ct_sip_parse_request(const struct nf_conn *ct,
                                const char *dptr, unsigned int datalen,

diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index 4b85e21..f73ab48 100644 (file)
--- 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;

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 813aa8c..217262e 100644 (file)
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -63,7 +63,9 @@ EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook);
 unsigned int (*nf_nat_sdp_hook)(struct sk_buff *skb,
                                const char **dptr,
                                unsigned int *datalen,
-                               struct nf_conntrack_expect *exp) __read_mostly;
+                               struct nf_conntrack_expect *rtp_exp,
+                               struct nf_conntrack_expect *rtcp_exp)
+                               __read_mostly;
 EXPORT_SYMBOL_GPL(nf_nat_sdp_hook);
 
 static int string_len(const struct nf_conn *ct, const char *dptr,
@@ -659,18 +661,20 @@ static void flush_expectations(struct nf_conn *ct, bool media)
        spin_unlock_bh(&nf_conntrack_lock);
 }
 
-static int set_expected_rtp(struct sk_buff *skb,
-                           const char **dptr, unsigned int *datalen,
-                           union nf_inet_addr *daddr, __be16 port)
+static int set_expected_rtp_rtcp(struct sk_buff *skb,
+                                const char **dptr, unsigned int *datalen,
+                                union nf_inet_addr *daddr, __be16 port)
 {
-       struct nf_conntrack_expect *exp;
+       struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp;
        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 *saddr;
        struct nf_conntrack_tuple tuple;
        int family = ct->tuplehash[!dir].tuple.src.l3num;
-       int skip_expect = 0, ret;
+       int skip_expect = 0, ret = NF_DROP;
+       u_int16_t base_port;
+       __be16 rtp_port, rtcp_port;
        typeof(nf_nat_sdp_hook) nf_nat_sdp;
 
        saddr = NULL;
@@ -704,23 +708,37 @@ static int set_expected_rtp(struct sk_buff *skb,
        if (skip_expect)
                return NF_ACCEPT;
 
-       exp = nf_ct_expect_alloc(ct);
-       if (exp == NULL)
-               return NF_DROP;
-       nf_ct_expect_init(exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
-                         IPPROTO_UDP, NULL, &port);
+       base_port = ntohs(tuple.dst.u.udp.port) & ~1;
+       rtp_port = htons(base_port);
+       rtcp_port = htons(base_port + 1);
+
+       rtp_exp = nf_ct_expect_alloc(ct);
+       if (rtp_exp == NULL)
+               goto err1;
+       nf_ct_expect_init(rtp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
+                         IPPROTO_UDP, NULL, &rtp_port);
+
+       rtcp_exp = nf_ct_expect_alloc(ct);
+       if (rtcp_exp == NULL)
+               goto err2;
+       nf_ct_expect_init(rtcp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
+                         IPPROTO_UDP, NULL, &rtcp_port);
 
        nf_nat_sdp = rcu_dereference(nf_nat_sdp_hook);
        if (nf_nat_sdp && ct->status & IPS_NAT_MASK)
-               ret = nf_nat_sdp(skb, dptr, datalen, exp);
+               ret = nf_nat_sdp(skb, dptr, datalen, rtp_exp, rtcp_exp);
        else {
-               if (nf_ct_expect_related(exp) != 0)
-                       ret = NF_DROP;
-               else
-                       ret = NF_ACCEPT;
+               if (nf_ct_expect_related(rtp_exp) == 0) {
+                       if (nf_ct_expect_related(rtcp_exp) != 0)
+                               nf_ct_unexpect_related(rtp_exp);
+                       else
+                               ret = NF_ACCEPT;
+               }
        }
-       nf_ct_expect_put(exp);
-
+       nf_ct_expect_put(rtcp_exp);
+err2:
+       nf_ct_expect_put(rtp_exp);
+err1:
        return ret;
 }
 
@@ -758,7 +776,7 @@ static int process_sdp(struct sk_buff *skb,
        if (port < 1024 || port > 65535)
                return NF_DROP;
 
-       return set_expected_rtp(skb, dptr, datalen, &addr, htons(port));
+       return set_expected_rtp_rtcp(skb, dptr, datalen, &addr, htons(port));
 }
 static int process_invite_response(struct sk_buff *skb,
                                   const char **dptr, unsigned int *datalen,
@@ -1101,7 +1119,7 @@ static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1
                .timeout        = 3 * 60,
        },
        [SIP_EXPECT_AUDIO] = {
-               .max_expected   = IP_CT_DIR_MAX,
+               .max_expected   = 2 * IP_CT_DIR_MAX,
                .timeout        = 3 * 60,
        },
 };