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res_pjsip_sdp_rtp: Add support for optimistic SRTP.

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Optimistic SRTP is the ability to enable SRTP but not have it be
a fatal requirement. If SRTP can be used it will be, if not it won't be.
This gives you a better chance of using it without having your sessions
fail when it can't be.

Encrypt all the things!

Review: https://reviewboard.asterisk.org/r/3992/
........

Merged revisions 428222 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@428224 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Joshua Colp
2014-11-19 12:50:47 +00:00
parent b2e766a6b7
commit 7f8b7ace72
9 changed files with 146 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
res/res_pjsip_sdp_rtp.c
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@@ -494,14 +494,41 @@ static void process_ice_attributes(struct ast_sip_session *session, struct ast_s
ice->start(session_media->rtp);
}
/*! \brief figure out if media stream has crypto lines for sdes */
static int media_stream_has_crypto(const struct pjmedia_sdp_media *stream)
{
int i;
for (i = 0; i < stream->attr_count; i++) {
pjmedia_sdp_attr *attr;
/* check the stream for the required crypto attribute */
attr = stream->attr[i];
if (pj_strcmp2(&attr->name, "crypto")) {
continue;
}
return 1;
}
return 0;
}
/*! \brief figure out media transport encryption type from the media transport string */
static enum ast_sip_session_media_encryption get_media_encryption_type(pj_str_t transport)
static enum ast_sip_session_media_encryption get_media_encryption_type(pj_str_t transport,
const struct pjmedia_sdp_media *stream, unsigned int *optimistic)
{
RAII_VAR(char *, transport_str, ast_strndup(transport.ptr, transport.slen), ast_free);
*optimistic = 0;
if (strstr(transport_str, "UDP/TLS")) {
return AST_SIP_MEDIA_ENCRYPT_DTLS;
} else if (strstr(transport_str, "SAVP")) {
return AST_SIP_MEDIA_ENCRYPT_SDES;
} else if (media_stream_has_crypto(stream)) {
*optimistic = 1;
return AST_SIP_MEDIA_ENCRYPT_SDES;
} else {
return AST_SIP_MEDIA_ENCRYPT_NONE;
}
@@ -523,22 +550,31 @@ static enum ast_sip_session_media_encryption check_endpoint_media_transport(
{
enum ast_sip_session_media_encryption incoming_encryption;
char transport_end = stream->desc.transport.ptr[stream->desc.transport.slen - 1];
unsigned int optimistic;
if ((transport_end == 'F' && !endpoint->media.rtp.use_avpf)
|| (transport_end != 'F' && endpoint->media.rtp.use_avpf)) {
return AST_SIP_MEDIA_TRANSPORT_INVALID;
}
incoming_encryption = get_media_encryption_type(stream->desc.transport);
incoming_encryption = get_media_encryption_type(stream->desc.transport, stream, &optimistic);
if (incoming_encryption == endpoint->media.rtp.encryption) {
return incoming_encryption;
}
if (endpoint->media.rtp.force_avp) {
if (endpoint->media.rtp.force_avp ||
endpoint->media.rtp.encryption_optimistic) {
return incoming_encryption;
}
/* If an optimistic offer has been made but encryption is not enabled consider it as having
* no offer of crypto at all instead of invalid so the session proceeds.
*/
if (optimistic) {
return AST_SIP_MEDIA_ENCRYPT_NONE;
}
return AST_SIP_MEDIA_TRANSPORT_INVALID;
}
@@ -697,7 +733,7 @@ static int setup_media_encryption(struct ast_sip_session *session,
const struct pjmedia_sdp_session *sdp,
const struct pjmedia_sdp_media *stream)
{
switch (session->endpoint->media.rtp.encryption) {
switch (session_media->encryption) {
case AST_SIP_MEDIA_ENCRYPT_SDES:
if (setup_sdes_srtp(session_media, stream)) {
return -1;
@@ -726,6 +762,8 @@ static int negotiate_incoming_sdp_stream(struct ast_sip_session *session, struct
char host[NI_MAXHOST];
RAII_VAR(struct ast_sockaddr *, addrs, NULL, ast_free_ptr);
enum ast_media_type media_type = stream_to_media_type(session_media->stream_type);
enum ast_sip_session_media_encryption encryption = AST_SIP_MEDIA_ENCRYPT_NONE;
int res;
/* If port is 0, ignore this media stream */
if (!stream->desc.port) {
@@ -740,9 +778,12 @@ static int negotiate_incoming_sdp_stream(struct ast_sip_session *session, struct
}
/* Ensure incoming transport is compatible with the endpoint's configuration */
if (!session->endpoint->media.rtp.use_received_transport &&
check_endpoint_media_transport(session->endpoint, stream) == AST_SIP_MEDIA_TRANSPORT_INVALID) {
return -1;
if (!session->endpoint->media.rtp.use_received_transport) {
encryption = check_endpoint_media_transport(session->endpoint, stream);
if (encryption == AST_SIP_MEDIA_TRANSPORT_INVALID) {
return -1;
}
}
ast_copy_pj_str(host, stream->conn ? &stream->conn->addr : &sdp->conn->addr, sizeof(host));
@@ -758,13 +799,27 @@ static int negotiate_incoming_sdp_stream(struct ast_sip_session *session, struct
return -1;
}
if (session->endpoint->media.rtp.use_received_transport) {
pj_strdup(session->inv_session->pool, &session_media->transport, &stream->desc.transport);
}
res = setup_media_encryption(session, session_media, sdp, stream);
if (res) {
if (!session->endpoint->media.rtp.encryption_optimistic) {
/* If optimistic encryption is disabled and crypto should have been enabled
* but was not this session must fail.
*/
return -1;
}
/* There is no encryption, sad. */
session_media->encryption = AST_SIP_MEDIA_ENCRYPT_NONE;
}
if (setup_media_encryption(session, session_media, sdp, stream)) {
return -1;
}
/* If we've been explicitly configured to use the received transport OR if
* encryption is on and crypto is present use the received transport.
* This is done in case of optimistic because it may come in as RTP/AVP or RTP/SAVP depending
* on the configuration of the remote endpoint (optimistic themselves or mandatory).
*/
if ((session->endpoint->media.rtp.use_received_transport) ||
((encryption == AST_SIP_MEDIA_ENCRYPT_SDES) && !res)) {
pj_strdup(session->inv_session->pool, &session_media->transport, &stream->desc.transport);
}
if (set_caps(session, session_media, stream)) {
return 0;
@@ -788,7 +843,7 @@ static int add_crypto_to_stream(struct ast_sip_session *session,
static const pj_str_t STR_ACTPASS = { "actpass", 7 };
static const pj_str_t STR_HOLDCONN = { "holdconn", 8 };
switch (session->endpoint->media.rtp.encryption) {
switch (session_media->encryption) {
case AST_SIP_MEDIA_ENCRYPT_NONE:
case AST_SIP_MEDIA_TRANSPORT_INVALID:
break;
@@ -923,11 +978,14 @@ static int create_outgoing_sdp_stream(struct ast_sip_session *session, struct as
}
media->desc.media = pj_str(session_media->stream_type);
if (session->endpoint->media.rtp.use_received_transport && pj_strlen(&session_media->transport)) {
if (pj_strlen(&session_media->transport)) {
/* If a transport has already been specified use it */
media->desc.transport = session_media->transport;
} else {
media->desc.transport = pj_str(ast_sdp_get_rtp_profile(
session->endpoint->media.rtp.encryption == AST_SIP_MEDIA_ENCRYPT_SDES,
/* Optimistic encryption places crypto in the normal RTP/AVP profile */
!session->endpoint->media.rtp.encryption_optimistic &&
(session_media->encryption == AST_SIP_MEDIA_ENCRYPT_SDES),
session_media->rtp, session->endpoint->media.rtp.use_avpf,
session->endpoint->media.rtp.force_avp));
}
@@ -1063,7 +1121,7 @@ static int apply_negotiated_sdp_stream(struct ast_sip_session *session, struct a
RAII_VAR(struct ast_sockaddr *, addrs, NULL, ast_free_ptr);
enum ast_media_type media_type = stream_to_media_type(session_media->stream_type);
char host[NI_MAXHOST];
int fdno;
int fdno, res;
if (!session->channel) {
return 1;
@@ -1084,10 +1142,18 @@ static int apply_negotiated_sdp_stream(struct ast_sip_session *session, struct a
return -1;
}
if (setup_media_encryption(session, session_media, remote, remote_stream)) {
res = setup_media_encryption(session, session_media, remote, remote_stream);
if (!session->endpoint->media.rtp.encryption_optimistic && res) {
/* If optimistic encryption is disabled and crypto should have been enabled but was not
* this session must fail.
*/
return -1;
}
if (!remote_stream->conn && !remote->conn) {
return 1;
}
ast_copy_pj_str(host, remote_stream->conn ? &remote_stream->conn->addr : &remote->conn->addr, sizeof(host));
/* Ensure that the address provided is valid */
@@ -1137,6 +1203,9 @@ static int apply_negotiated_sdp_stream(struct ast_sip_session *session, struct a
session_media->remotely_held = 0;
}
/* This purposely resets the encryption to the configured in case it gets added later */
session_media->encryption = session->endpoint->media.rtp.encryption;
return 1;
}