Make MSS clamping configurable, but enabled by default.

[tinc] / src / route.c

diff --git a/src/route.c b/src/route.c
index 77bec04..c04b0ad 100644 (file)
--- a/src/route.c
+++ b/src/route.c
@@ -94,7 +94,7 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 }
 
 static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
-       if(!via || via == myself)
+       if(!via || via == myself || !(via->options & OPTION_CLAMP_MSS))
                return;
 
        /* Find TCP header */
@@ -112,6 +112,9 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
        /* Use data offset field to calculate length of options field */
        int len = ((packet->data[start + 12] >> 4) - 5) * 4;
 
+       if(packet->len < start + 20 + len)
+               return;
+
        /* Search for MSS option header */
        for(int i = 0; i < len;) {
                if(packet->data[start + 20 + i] == 0)