glibc/resolv/res_enable_icmp.c
Florian Weimer 08504de718 resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]
The Linux kernel suppresses some ICMP error messages by default for
UDP sockets.  This commit enables full ICMP error reporting,
hopefully resulting in faster failover to working name servers.
2019-03-12 11:40:47 +01:00

38 lines
1.2 KiB
C

/* Enable full ICMP errors on a socket.
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <netinet/in.h>
#include <sys/socket.h>
int
__res_enable_icmp (int family, int fd)
{
int one = 1;
switch (family)
{
case AF_INET:
return setsockopt (fd, SOL_IP, IP_RECVERR, &one, sizeof (one));
case AF_INET6:
return setsockopt (fd, SOL_IPV6, IPV6_RECVERR, &one, sizeof (one));
default:
__set_errno (EAFNOSUPPORT);
return -1;
}
}