neels has uploaded this change for review.
IuUP: always allow Initialization
Do not refuse IuUP Initialization messages coming in on an RTP port.
If an IUFP conn is not yet configured (pre-Initialization), allow rx
from any remote address.
If we refuse the IuUP Initialization, a 3G RNC may fail to set up a RAB.
We will know the remote address only *after* assigning a RAB succeeded.
So the IuUP Initialization must be allowed before knowing all addresses.
At the time of writing, CRCX for IUFP are sent to osmo-mgw in either
LOOPBACK or in RECVONLY mode:
- current osmo-msc: recvonly
- osmo-msc <= v1.10.0: loopback
- osmo-hnbgw: loopback
IuUP Initialization should work regardless of that.
See also next patch I158dd046fdfcb10392cde3de8cc88dd095a05b40
IuUP is one layer below the loopback/send/recv decision for RTP; IuUP is
always terminated at the MGW, while the AMR payload carries through.
Decided for now that it's not worth the extra effort to make this more
restrictive; ideas would be:
- actually verify the incoming packet to have a valid IuUP Init header
before permitting it to be received.
- as soon as the remote address is known, also validate the src for IuUP
Initialization messages.
This patch is nice and simple and does the job.
Related: alternative patch Idd833997abce46886e9664505b2776fa5dadc8db
Related: SYS#6657
Change-Id: I6c365559a7bd197349f0ea99f7a13b56a4bb580b
---
M src/libosmo-mgcp/mgcp_network.c
1 file changed, 47 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-mgw refs/changes/05/35205/1
diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 46d0cb4..e060c1d 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -834,6 +834,15 @@
{
char ipbuf[INET6_ADDRSTRLEN];
+ /* Allow IuUP Initialization to get through even if we don't have a remote address set yet. */
+ if (mgcp_conn_rtp_is_iuup(conn) && !conn->iuup.configured) {
+ /* maybe todo: also verify that it is actually a valid IuUP Initialization header in the incoming msgb?
+ * (though, why do we even care where the RTP is coming from) */
+ LOGPCONN(conn->conn, DRTP, LOGL_INFO, "Rx RTP from %s: allowing unknown src for IuUP Initialization\n",
+ osmo_sockaddr_to_str(addr));
+ return 0;
+ }
+
if (osmo_sockaddr_is_any(&conn->end.addr) != 0) {
switch (conn->conn->mode) {
case MGCP_CONN_LOOPBACK:
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