An OPTIONS request received at stack via UDP transport has two Content-Length
The message is showed below:
OPTIONS sip:172.21.115.16 SIP/2.0
CSeq: 141 OPTIONS
Via: SIP/2.0/UDP 172.21.110.107:5060;branch=z9hG4bKkdjuw3990
Expected: Stack responds with 400 Bad Request.
Actual: Stack chooses the last Content-Length header, and then process the
RFC4475 Section3.3.9. Multiple Content-Length Values
Multiple conflicting Content-Length header field values appear in this
From a framing perspective, this situation is equivalent to an invalid
Content-Length value (or no value at all).
An element receiving this message should respond with an error. This request
appeared over UDP, so the remainder of the datagram can simply be discarded. If
a request like this arrives over TCP, the framing error is not recoverable, and
the connection should be closed.