static bool sdp_attr_handler(const char *name, const char *value, void *arg)
{
struct menc_st *st = arg;
struct crypto c;
(void)name;
if (sdes_decode_crypto(&c, value))
return false;
if (0 != pl_strcmp(&c.key_method, "inline"))
return false;
if (!cryptosuite_issupported(&c.suite))
return false;
st->crypto_suite = mem_deref(st->crypto_suite);
pl_strdup(&st->crypto_suite, &c.suite);
if (start_crypto(st, &c.key_info))
return false;
sdp_enc(st, st->sdpm, c.tag, st->crypto_suite);
return true;
}
static int alloc(struct menc_media **stp, struct menc_sess *sess,
struct rtp_sock *rtp,
int proto, void *rtpsock, void *rtcpsock,
struct sdp_media *sdpm)
{
struct menc_st *st;
const char *rattr = NULL;
int layer = 10; /* above zero */
int err = 0;
bool mux = (rtpsock == rtcpsock);
(void)sess;
(void)rtp;
if (!stp || !sdpm)
return EINVAL;
if (proto != IPPROTO_UDP)
return EPROTONOSUPPORT;
st = (struct menc_st *)*stp;
if (!st) {
st = mem_zalloc(sizeof(*st), destructor);
if (!st)
return ENOMEM;
st->sdpm = mem_ref(sdpm);
err = sdp_media_set_alt_protos(st->sdpm, 4,
"RTP/AVP",
"RTP/AVPF",
"RTP/SAVP",
"RTP/SAVPF");
if (err)
goto out;
if (rtpsock) {
st->rtpsock = mem_ref(rtpsock);
err |= udp_register_helper(&st->uh_rtp, rtpsock,
layer, send_handler,
recv_handler, st);
}
if (rtcpsock && !mux) {
st->rtcpsock = mem_ref(rtcpsock);
err |= udp_register_helper(&st->uh_rtcp, rtcpsock,
layer, send_handler,
recv_handler, st);
}
if (err)
goto out;
/* set our preferred crypto-suite */
err |= str_dup(&st->crypto_suite, aes_cm_128_hmac_sha1_80);
if (err)
goto out;
err = setup_srtp(st);
if (err)
goto out;
}
/* SDP handling */
if (sdp_media_rattr(st->sdpm, "crypto")) {
rattr = sdp_media_rattr_apply(st->sdpm, "crypto",
sdp_attr_handler, st);
if (!rattr) {
DEBUG_WARNING("no valid a=crypto attribute from"
" remote peer\n");
}
}
if (!rattr)
err = sdp_enc(st, sdpm, 0, st->crypto_suite);
out:
if (err)
mem_deref(st);
else
*stp = (struct menc_media *)st;
return err;
}
static int media_alloc(struct menc_media **stp, struct menc_sess *sess,
struct rtp_sock *rtp,
struct udp_sock *rtpsock, struct udp_sock *rtcpsock,
const struct sa *raddr_rtp,
const struct sa *raddr_rtcp,
struct sdp_media *sdpm)
{
struct menc_st *st;
const char *rattr = NULL;
int layer = 10; /* above zero */
int err = 0;
bool mux = (rtpsock == rtcpsock);
(void)sess;
(void)rtp;
(void)raddr_rtp;
(void)raddr_rtcp;
if (!stp || !sdpm || !sess)
return EINVAL;
st = (struct menc_st *)*stp;
if (!st) {
st = mem_zalloc(sizeof(*st), destructor);
if (!st)
return ENOMEM;
st->sess = sess;
st->sdpm = mem_ref(sdpm);
if (0 == str_cmp(sdp_media_proto(sdpm), "RTP/AVP")) {
err = sdp_media_set_alt_protos(st->sdpm, 4,
"RTP/AVP",
"RTP/AVPF",
"RTP/SAVP",
"RTP/SAVPF");
if (err)
goto out;
}
if (rtpsock) {
st->rtpsock = mem_ref(rtpsock);
err |= udp_register_helper(&st->uh_rtp, rtpsock,
layer, send_handler,
recv_handler, st);
}
if (rtcpsock && !mux) {
st->rtcpsock = mem_ref(rtcpsock);
err |= udp_register_helper(&st->uh_rtcp, rtcpsock,
layer, send_handler,
recv_handler, st);
}
if (err)
goto out;
/* set our preferred crypto-suite */
err |= str_dup(&st->crypto_suite, preferred_suite);
if (err)
goto out;
rand_bytes(st->key_tx, sizeof(st->key_tx));
}
/* SDP handling */
if (sdp_media_rport(sdpm))
st->got_sdp = true;
if (sdp_media_rattr(st->sdpm, "crypto")) {
rattr = sdp_media_rattr_apply(st->sdpm, "crypto",
sdp_attr_handler, st);
if (!rattr) {
warning("srtp: no valid a=crypto attribute from"
" remote peer\n");
}
}
if (!rattr)
err = sdp_enc(st, sdpm, 1, st->crypto_suite);
out:
if (err)
mem_deref(st);
else
*stp = (struct menc_media *)st;
return err;
}