The code in link_socket_write_udp_posix_sendmsg() for the IP_RECVDESTADDR
case was sending a too-large control message (sizeof openvpn_pktinfo,
which is a union for IPv4+IPv6) instead of just openvpn_in4_pktinfo,
leading to sendmsg() refusing to send the packet.
Use RFC 2292 macros for alignment + size calculation.
Fix trac#327
Signed-off-by: Gert Doering <g...@greenie.muc.de>
---
src/openvpn/socket.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index 100eedd..525b864 100644
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -2835,11 +2835,11 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
mesg.msg_name = &to->dest.addr.sa;
mesg.msg_namelen = sizeof (struct sockaddr_in);
mesg.msg_control = &opi;
- mesg.msg_controllen = sizeof (struct openvpn_in4_pktinfo);
mesg.msg_flags = 0;
+#ifdef HAVE_IN_PKTINFO
+ mesg.msg_controllen = sizeof (struct openvpn_in4_pktinfo);
cmsg = CMSG_FIRSTHDR (&mesg);
cmsg->cmsg_len = sizeof (struct openvpn_in4_pktinfo);
-#ifdef HAVE_IN_PKTINFO
cmsg->cmsg_level = SOL_IP;
cmsg->cmsg_type = IP_PKTINFO;
{
@@ -2850,6 +2850,10 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
pkti->ipi_addr.s_addr = 0;
}
#elif defined(IP_RECVDSTADDR)
+ ASSERT( CMSG_SPACE(sizeof (struct in_addr)) <= sizeof(opi) );
+ mesg.msg_controllen = CMSG_SPACE(sizeof (struct in_addr));
+ cmsg = CMSG_FIRSTHDR (&mesg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_RECVDSTADDR;
*(struct in_addr *) CMSG_DATA (cmsg) = to->pi.in4;
--
1.8.3.2
