The new code to enable IPv6 extended error reporting will cause
an error ("Protocol not available (errno=92)") if trying to enable
that setsockopt() option on an IPv4-only socket.
Fix: pass sock->info.af to set_sock_extended_error_passing(), only
apply to AF_INET6 sockets.
To make that work, ensure that sock->info.af is set to not only
the value coming from config (which might be AF_UNSPEC) but to the
actual value used in socket creation (credits: Arne Schwabe).
Add comments to make explicit that the asymmetry here (IPv4 extended
socket error reporting is enabled on all sockets) is intentional.
Signed-off-by: Gert Doering <g...@greenie.muc.de>
--
v2: set sock->info.af in create_socket() (Arne Schwabe)
---
src/openvpn/mtu.c | 13 +++++++++----
src/openvpn/mtu.h | 2 +-
src/openvpn/socket.c | 6 +++++-
3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/src/openvpn/mtu.c b/src/openvpn/mtu.c
index 59b91798..f60f4853 100644
--- a/src/openvpn/mtu.c
+++ b/src/openvpn/mtu.c
@@ -413,17 +413,22 @@ exit:
}
void
-set_sock_extended_error_passing(int sd)
+set_sock_extended_error_passing(int sd, sa_family_t proto_af)
{
int on = 1;
- /* see "man 7 ip" (on Linux) */
+ /* see "man 7 ip" (on Linux)
+ * this works on IPv4 and IPv6(-dual-stack) sockets (v4-mapped)
+ */
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)
+ /* see "man 7 ipv6" (on Linux)
+ * this only works on IPv6 sockets
+ */
+ if (proto_af == AF_INET6
+ && 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)");
diff --git a/src/openvpn/mtu.h b/src/openvpn/mtu.h
index 9db6cf26..d4856f16 100644
--- a/src/openvpn/mtu.h
+++ b/src/openvpn/mtu.h
@@ -268,7 +268,7 @@ void alloc_buf_sock_tun(struct buffer *buf,
#if EXTENDED_SOCKET_ERROR_CAPABILITY
-void set_sock_extended_error_passing(int sd);
+void set_sock_extended_error_passing(int sd, sa_family_t proto_af);
const char *format_extended_socket_error(int fd, int *mtu, struct gc_arena
*gc);
diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index 4e4a3a2f..b4c20f69 100644
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -1131,6 +1131,10 @@ create_socket(struct link_socket *sock, struct addrinfo
*addr)
{
ASSERT(0);
}
+ /* Set af field of sock->info, so it always reflects the address family
+ * of the created socket */
+ sock->info.af = addr->ai_family;
+
/* set socket buffers based on --sndbuf and --rcvbuf options */
socket_set_buffers(sock->sd, &sock->socket_buffer_sizes);
@@ -1949,7 +1953,7 @@ phase2_set_socket_flags(struct link_socket *sock)
#if EXTENDED_SOCKET_ERROR_CAPABILITY
/* if the OS supports it, enable extended error passing on the socket */
- set_sock_extended_error_passing(sock->sd);
+ set_sock_extended_error_passing(sock->sd, sock->info.af);
#endif
}
--
2.35.1
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