From ebb05c1f90e97d0795230e90ea49af7d084dc9fe Mon Sep 17 00:00:00 2001
From: Pau Espin Pedrol <pespin@sysmocom.de>
Date: Thu, 16 Dec 2021 16:11:06 +0100
Subject: [PATCH] mgcp_network.c: Set proper CRC Header for ACK Initialization

Discovered while debugging wireshark CRC calculation and implementing
new IuUP code in libosmocore.

Change-Id: Ic8350d1f9a9e5dcefeb787462d267bfac08d778f
---
 src/libosmo-mgcp/mgcp_network.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 2d275ec8d..264e263bc 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -1225,6 +1225,7 @@ int mgcp_send(struct mgcp_endpoint *endp, int is_rtp, struct osmo_sockaddr *addr
 				if (data[0] == 0xe0) {
 					data[0] = 0xe4;
 					data[1] = 0x00;
+					data[2] = 0x09; /* Patch CRC Header to adapt to new header above */
 					rtp_state->patched_first_rtp_payload = true;
 					LOGPENDP(endp, DRTP, LOGL_DEBUG,
 						 "Patching over first two bytes"