Try to set DF bit on BSDs as well.

Every operating system seems to have its own, slightly different way to disable
packet fragmentation. Emit a compiler warning when no suitable way is found.
On OpenBSD, it seems impossible to do it for IPv4.

diff --git a/src/net_socket.c b/src/net_socket.c
index cd41e37..9538806 100644 (file)
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -261,9 +261,13 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
        option = 1;
        setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 
-#if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
+#if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
        if(sa->sa.sa_family == AF_INET6)
-               setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
+               setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, &option, sizeof option);
+#endif
+
+#if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
+#define IP_DONTFRAGMENT IP_DONTFRAG
 #endif
 
 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
@@ -276,6 +280,8 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
                option = 1;
                setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, &option, sizeof(option));
        }
+#else
+#warning No way to disable IPv4 fragmentation
 #endif
 
 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
@@ -283,6 +289,13 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
                option = IPV6_PMTUDISC_DO;
                setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
        }
+#elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
+       if(myself->options & OPTION_PMTU_DISCOVERY) {
+               option = 1;
+               setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, &option, sizeof(option));
+       }
+#else
+#warning No way to disable IPv6 fragmentation
 #endif
 
        if (!bind_to_interface(nfd)) {