netfilter: nf_conntrack_sip: add T.38 FAX support

Signed-off-by: Patrick McHardy <kaber@trash.net>

3 files changed, 25 insertions, 6 deletions

diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h
index cd84d6f44d11..ff8cfbcf3b81 100644
--- a/include/linux/netfilter/nf_conntrack_sip.h
+++ b/include/linux/netfilter/nf_conntrack_sip.h
@@ -14,6 +14,7 @@ enum sip_expectation_classes {
         SIP_EXPECT_SIGNALLING,
         SIP_EXPECT_AUDIO,
         SIP_EXPECT_VIDEO,
+        SIP_EXPECT_IMAGE,
         __SIP_EXPECT_MAX
 };
 #define SIP_EXPECT_MAX  (__SIP_EXPECT_MAX - 1)
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 5043d61c99a7..5b7d8835523f 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -70,7 +70,7 @@ union nf_conntrack_help {
 struct nf_conntrack_helper;
 
 /* Must be kept in sync with the classes defined by helpers */
-#define NF_CT_MAX_EXPECT_CLASSES        3
+#define NF_CT_MAX_EXPECT_CLASSES        4
 
 /* nf_conn feature for connections that have a helper */
 struct nf_conn_help {
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 3bb3aaff76e9..fbe8ff5a420a 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -907,6 +907,7 @@ err1:
 static const struct sdp_media_type sdp_media_types[] = {
         SDP_MEDIA_TYPE("audio ", SIP_EXPECT_AUDIO),
         SDP_MEDIA_TYPE("video ", SIP_EXPECT_VIDEO),
+        SDP_MEDIA_TYPE("image ", SIP_EXPECT_IMAGE),
 };
 
 static const struct sdp_media_type *sdp_media_type(const char *dptr,
@@ -932,7 +933,6 @@ static int process_sdp(struct sk_buff *skb, unsigned int dataoff,
 {
         enum ip_conntrack_info ctinfo;
         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-        struct nf_conn_help *help = nfct_help(ct);
         unsigned int matchoff, matchlen;
         unsigned int mediaoff, medialen;
         unsigned int sdpoff;
@@ -1024,9 +1024,6 @@ static int process_sdp(struct sk_buff *skb, unsigned int dataoff,
                 ret = nf_nat_sdp_session(skb, dataoff, dptr, datalen, sdpoff,
                                          &rtp_addr);
 
-        if (ret == NF_ACCEPT && i > 0)
-                help->help.ct_sip_info.invite_cseq = cseq;
-
         return ret;
 }
 static int process_invite_response(struct sk_buff *skb, unsigned int dataoff,
@@ -1077,6 +1074,22 @@ static int process_prack_response(struct sk_buff *skb, unsigned int dataoff,
         return NF_ACCEPT;
 }
 
+static int process_invite_request(struct sk_buff *skb, unsigned int dataoff,
+                                  const char **dptr, unsigned int *datalen,
+                                  unsigned int cseq)
+{
+        enum ip_conntrack_info ctinfo;
+        struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+        struct nf_conn_help *help = nfct_help(ct);
+        unsigned int ret;
+
+        flush_expectations(ct, true);
+        ret = process_sdp(skb, dataoff, dptr, datalen, cseq);
+        if (ret == NF_ACCEPT)
+                help->help.ct_sip_info.invite_cseq = cseq;
+        return ret;
+}
+
 static int process_bye_request(struct sk_buff *skb, unsigned int dataoff,
                                const char **dptr, unsigned int *datalen,
                                unsigned int cseq)
@@ -1257,7 +1270,7 @@ flush:
 }
 
 static const struct sip_handler sip_handlers[] = {
-        SIP_HANDLER("INVITE", process_sdp, process_invite_response),
+        SIP_HANDLER("INVITE", process_invite_request, process_invite_response),
         SIP_HANDLER("UPDATE", process_sdp, process_update_response),
         SIP_HANDLER("ACK", process_sdp, NULL),
         SIP_HANDLER("PRACK", process_sdp, process_prack_response),
@@ -1473,6 +1486,11 @@ static const struct nf_conntrack_expect_policy sip_exp_policy[SIP_EXPECT_MAX + 1
                 .max_expected   = 2 * IP_CT_DIR_MAX,
                 .timeout        = 3 * 60,
         },
+        [SIP_EXPECT_IMAGE] = {
+                .name           = "image",
+                .max_expected   = IP_CT_DIR_MAX,
+                .timeout        = 3 * 60,
+        },
 };
 
 static void nf_conntrack_sip_fini(void)