From: Lorenz Bauer lmb@isovalent.com Date: Wed, 14 Jun 2023 16:25:05 +0100
On Tue, Jun 13, 2023 at 7:57 PM Kuniyuki Iwashima kuniyu@amazon.com wrote:
else { result = sk; }The assignment to result below is buggy. Let's say SO_REUSEPROT group have TCP_CLOSE and TCP_ESTABLISHED sockets.
I'm not very familiar with SO_REUSEPORT, I assumed (incorrectly probably) that such a group would only ever have TCP_CLOSE in UDP case and TCP_LISTENING in TCP case. Can you explain how I could end up in this situation?
When we call conenct() for UDP socket in SO_REUSEPORT group, the state is changed from TCP_CLOSE to TCP_ESTABLISHED in __ip4_datagram_connect(), and the socket remains in the group.
That's why we check TCP_ESTABLISHED in reuseport_select_sock_by_hash() that is always false for TCP but true for UDP in the case above.