[NETFILTER]: nf_conntrack_sip: support multiple media channels
Add support for multiple media channels and use it to create
expectations for video streams when present.
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
commit 1c04320897b232a4b7dd89c123469f6c6de911ae
tree 74dd9d95ee604f0b907b138d2a1c214cf87a95e6
parent 1f7d1e1804a04963595888f07e17453d2d5996f4
author Patrick McHardy <kaber@xxxxxxxxx> Tue, 25 Mar 2008 12:45:24 +0100
committer Patrick McHardy <kaber@xxxxxxxxx> Tue, 25 Mar 2008 14:09:59 +0100
include/linux/netfilter/nf_conntrack_sip.h | 14 +++
include/net/netfilter/nf_conntrack.h | 2
net/netfilter/nf_conntrack_sip.c | 121 +++++++++++++++++++++-------
3 files changed, 105 insertions(+), 32 deletions(-)
diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h
index eca3ad3..71fa3eb 100644
--- a/include/linux/netfilter/nf_conntrack_sip.h
+++ b/include/linux/netfilter/nf_conntrack_sip.h
@@ -12,10 +12,24 @@ struct nf_ct_sip_master {
enum sip_expectation_classes {
SIP_EXPECT_SIGNALLING,
SIP_EXPECT_AUDIO,
+ SIP_EXPECT_VIDEO,
__SIP_EXPECT_MAX
};
#define SIP_EXPECT_MAX (__SIP_EXPECT_MAX - 1)
+struct sdp_media_type {
+ const char *name;
+ unsigned int len;
+ enum sip_expectation_classes class;
+};
+
+#define SDP_MEDIA_TYPE(__name, __class) \
+{ \
+ .name = (__name), \
+ .len = sizeof(__name) - 1, \
+ .class = (__class), \
+}
+
struct sip_handler {
const char *method;
unsigned int len;
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 4a4f870..a3567a7 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -78,7 +78,7 @@ do { \
struct nf_conntrack_helper;
/* Must be kept in sync with the classes defined by helpers */
-#define NF_CT_MAX_EXPECT_CLASSES 2
+#define NF_CT_MAX_EXPECT_CLASSES 3
/* 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 f929add..f40a525 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -112,6 +112,21 @@ static int digits_len(const struct nf_conn *ct, const char *dptr,
return len;
}
+/* get media type + port length */
+static int media_len(const struct nf_conn *ct, const char *dptr,
+ const char *limit, int *shift)
+{
+ int len = string_len(ct, dptr, limit, shift);
+
+ dptr += len;
+ if (dptr >= limit || *dptr != ' ')
+ return 0;
+ len++;
+ dptr++;
+
+ return len + digits_len(ct, dptr, limit, shift);
+}
+
static int parse_addr(const struct nf_conn *ct, const char *cp,
const char **endp, union nf_inet_addr *addr,
const char *limit)
@@ -563,7 +578,7 @@ static const struct sip_header ct_sdp_hdrs[] = {
[SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", epaddr_len),
[SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", epaddr_len),
[SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", epaddr_len),
- [SDP_HDR_MEDIA] = SDP_HDR("m=", "audio ", digits_len),
+ [SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len),
};
/* Linear string search within SDP header values */
@@ -705,6 +720,7 @@ static void flush_expectations(struct nf_conn *ct, bool media)
static int set_expected_rtp_rtcp(struct sk_buff *skb,
const char **dptr, unsigned int *datalen,
union nf_inet_addr *daddr, __be16 port,
+ enum sip_expectation_classes class,
unsigned int mediaoff, unsigned int medialen)
{
struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp;
@@ -743,7 +759,7 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
exp = __nf_ct_expect_find(&tuple);
if (exp && exp->master != ct &&
nfct_help(exp->master)->helper == nfct_help(ct)->helper &&
- exp->class == SIP_EXPECT_AUDIO)
+ exp->class == class)
skip_expect = 1;
rcu_read_unlock();
@@ -757,13 +773,13 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
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,
+ nf_ct_expect_init(rtp_exp, class, 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,
+ nf_ct_expect_init(rtcp_exp, class, family, saddr, daddr,
IPPROTO_UDP, NULL, &rtcp_port);
nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook);
@@ -785,6 +801,28 @@ err1:
return ret;
}
+static const struct sdp_media_type sdp_media_types[] = {
+ SDP_MEDIA_TYPE("audio ", SIP_EXPECT_AUDIO),
+ SDP_MEDIA_TYPE("video ", SIP_EXPECT_VIDEO),
+};
+
+static const struct sdp_media_type *sdp_media_type(const char *dptr,
+ unsigned int matchoff,
+ unsigned int matchlen)
+{
+ const struct sdp_media_type *t;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(sdp_media_types); i++) {
+ t = &sdp_media_types[i];
+ if (matchlen < t->len ||
+ strncmp(dptr + matchoff, t->name, t->len))
+ continue;
+ return t;
+ }
+ return NULL;
+}
+
static int process_sdp(struct sk_buff *skb,
const char **dptr, unsigned int *datalen,
unsigned int cseq)
@@ -796,13 +834,16 @@ static int process_sdp(struct sk_buff *skb,
unsigned int mediaoff, medialen;
unsigned int sdpoff;
unsigned int caddr_len, maddr_len;
+ unsigned int i;
union nf_inet_addr caddr, maddr, rtp_addr;
unsigned int port;
enum sdp_header_types c_hdr;
- int ret;
+ const struct sdp_media_type *t;
+ int ret = NF_ACCEPT;
typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr;
typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session;
+ nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook);
c_hdr = family == AF_INET ? SDP_HDR_CONNECTION_IP4 :
SDP_HDR_CONNECTION_IP6;
@@ -822,41 +863,55 @@ static int process_sdp(struct sk_buff *skb,
&matchoff, &matchlen, &caddr) > 0)
caddr_len = matchlen;
- if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen,
- SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
- &mediaoff, &medialen) <= 0)
- return NF_ACCEPT;
+ mediaoff = sdpoff;
+ for (i = 0; i < ARRAY_SIZE(sdp_media_types); ) {
+ if (ct_sip_get_sdp_header(ct, *dptr, mediaoff, *datalen,
+ SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
+ &mediaoff, &medialen) <= 0)
+ break;
- port = simple_strtoul(*dptr + mediaoff, NULL, 10);
- if (port < 1024 || port > 65535)
- return NF_DROP;
+ /* Get media type and port number. A media port value of zero
+ * indicates an inactive stream. */
+ t = sdp_media_type(*dptr, mediaoff, medialen);
+ if (!t) {
+ mediaoff += medialen;
+ continue;
+ }
+ mediaoff += t->len;
+ medialen -= t->len;
- /* The media description overrides the session description. */
- maddr_len = 0;
- if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen,
- c_hdr, SDP_HDR_MEDIA,
- &matchoff, &matchlen, &maddr) > 0) {
- maddr_len = matchlen;
- memcpy(&rtp_addr, &maddr, sizeof(rtp_addr));
- } else if (caddr_len)
- memcpy(&rtp_addr, &caddr, sizeof(rtp_addr));
- else
- return NF_DROP;
+ port = simple_strtoul(*dptr + mediaoff, NULL, 10);
+ if (port == 0)
+ continue;
+ if (port < 1024 || port > 65535)
+ return NF_DROP;
- ret = set_expected_rtp_rtcp(skb, dptr, datalen, &rtp_addr, htons(port),
- mediaoff, medialen);
- if (ret != NF_ACCEPT)
- return ret;
+ /* The media description overrides the session description. */
+ maddr_len = 0;
+ if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen,
+ c_hdr, SDP_HDR_MEDIA,
+ &matchoff, &matchlen, &maddr) > 0) {
+ maddr_len = matchlen;
+ memcpy(&rtp_addr, &maddr, sizeof(rtp_addr));
+ } else if (caddr_len)
+ memcpy(&rtp_addr, &caddr, sizeof(rtp_addr));
+ else
+ return NF_DROP;
+
+ ret = set_expected_rtp_rtcp(skb, dptr, datalen,
+ &rtp_addr, htons(port), t->class,
+ mediaoff, medialen);
+ if (ret != NF_ACCEPT)
+ return ret;
- /* Update media connection address if present */
- if (maddr_len) {
- nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook);
- if (nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) {
+ /* Update media connection address if present */
+ if (maddr_len && nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) {
ret = nf_nat_sdp_addr(skb, dptr, mediaoff, datalen,
c_hdr, SDP_HDR_MEDIA, &rtp_addr);
if (ret != NF_ACCEPT)
return ret;
}
+ i++;
}
/* Update session connection and owner addresses */
@@ -1210,6 +1265,10 @@ 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_VIDEO] = {
+ .max_expected = 2 * IP_CT_DIR_MAX,
+ .timeout = 3 * 60,
+ },
};
static void nf_conntrack_sip_fini(void)
--
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