From 7af0bae4ce511455d84109bcd9faad660c7ad2f3 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 16 Jun 2022 15:06:05 +0200 Subject: [PATCH] tap: Add informational messages for UNIX domain socket connections ...namely, as connections are discarded or accepted. This was quite useful to debug an issue with libvirtd failing to start qemu (because passt refused the new connection) as a previous qemu instance was still active. Signed-off-by: Stefano Brivio --- tap.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tap.c b/tap.c index 04ceade..a3c711c 100644 --- a/tap.c +++ b/tap.c @@ -856,12 +856,19 @@ static void tap_sock_unix_new(struct ctx *c) { struct epoll_event ev = { 0 }; int v = INT_MAX / 2; + struct ucred ucred; + socklen_t len; + + len = sizeof(ucred); /* Another client is already connected: accept and close right away. */ if (c->fd_tap != -1) { int discard = accept4(c->fd_tap_listen, NULL, NULL, SOCK_NONBLOCK); + if (!getsockopt(discard, SOL_SOCKET, SO_PEERCRED, &ucred, &len)) + info("discarding connection from PID %i", ucred.pid); + if (discard != -1) close(discard); @@ -870,6 +877,9 @@ static void tap_sock_unix_new(struct ctx *c) c->fd_tap = accept4(c->fd_tap_listen, NULL, NULL, 0); + if (!getsockopt(c->fd_tap, SOL_SOCKET, SO_PEERCRED, &ucred, &len)) + info("accepted connection from PID %i", ucred.pid); + if (!c->low_rmem && setsockopt(c->fd_tap, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v))) trace("tap: failed to set SO_RCVBUF to %i", v);