Commit 4225114b96 repaired "--mtu-disc yes" brokenness for IPv4 UDP sockets
(caused by autoconf/ifdef issues). This patch adds new functionality
to do --mtu-disc for IPv6 sockets as well.
Half of it (setsockopt(IPV6_MTU_DISCOVER)) was already there, but
receiving of detailed socket errors was missing the enablement of
setsockopt(IPV6_RECVERR) and parsing of IPPROTO_IPV6/IPV6_RECVERR
messages received.
With that, we now get (sending over a route with "mtu 1300"):
2022-02-22 15:28:07 write UDPv6 [EMSGSIZE Path-MTU=1300]: Message too long
(fd=3,code=90)
2022-02-22 15:28:07 Note adjusting 'mssfix 1400 mtu' to 'mssfix 1300 mtu'
according to path MTU discovery
2022-02-22 15:28:07 Note adjusting 'fragment 1400 mtu' to 'fragment 1300 mtu'
according to path MTU discovery
Signed-off-by: Gert Doering <g...@greenie.muc.de>
---
src/openvpn/mtu.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/src/openvpn/mtu.c b/src/openvpn/mtu.c
index aa810f1c..51eeaa64 100644
--- a/src/openvpn/mtu.c
+++ b/src/openvpn/mtu.c
@@ -352,6 +352,17 @@ format_extended_socket_error(int fd, int *mtu, struct
gc_arena *gc)
buf_printf(&out,"CMSG=%d|", cmsg->cmsg_type);
}
}
+ else if (cmsg->cmsg_level == IPPROTO_IPV6)
+ {
+ if (cmsg->cmsg_type == IPV6_RECVERR)
+ {
+ e = (struct sock_extended_err *) CMSG_DATA(cmsg);
+ }
+ else
+ {
+ buf_printf(&out,"CMSG=%d|", cmsg->cmsg_type);
+ }
+ }
}
if (e == NULL)
{
@@ -405,11 +416,18 @@ void
set_sock_extended_error_passing(int sd)
{
int on = 1;
- if (setsockopt(sd, SOL_IP, IP_RECVERR, (void *) &on, sizeof(on)))
+ /* see "man 7 ip" (on Linux) */
+ if (setsockopt(sd, SOL_IP, IP_RECVERR, (void *) &on, sizeof(on)) != 0)
{
msg(M_WARN | M_ERRNO,
"Note: enable extended error passing on TCP/UDP socket failed
(IP_RECVERR)");
}
+ /* see "man 7 ipv6" (on Linux) */
+ if (setsockopt(sd, IPPROTO_IPV6, IPV6_RECVERR, (void *) &on, sizeof(on))
!= 0)
+ {
+ msg(M_WARN | M_ERRNO,
+ "Note: enable extended error passing on TCP/UDP socket failed
(IPV6_RECVERR)");
+ }
}
#endif /* if EXTENDED_SOCKET_ERROR_CAPABILITY */
--
2.26.3
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