Work around a GCC bug that causes inet_checksum() to give wrong results.

[tinc] / src / route.c

diff --git a/src/route.c b/src/route.c
index 92dc1cd..4d71279 100644 (file)
--- a/src/route.c
+++ b/src/route.c
@@ -59,6 +59,7 @@ static const size_t opt_size = sizeof(struct nd_opt_hdr);
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #endif
 
+volatile int dummy;
 static timeout_t age_subnets_timeout;
 
 /* RFC 1071 */
@@ -80,6 +81,11 @@ static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
                checksum = (checksum & 0xFFFF) + (checksum >> 16);
        }
 
+       // Work around a compiler optimization bug.
+       if(checksum) {
+               dummy = 1;
+       }
+
        return ~checksum;
 }
 
@@ -651,11 +657,13 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
        }
 
        if(!subnet->owner->status.reachable) {
-               return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+               route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+               return;
        }
 
        if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
-               return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+               route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+               return;
        }
 
        if(decrement_ttl && source != myself && subnet->owner != myself)
@@ -675,7 +683,8 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
        }
 
        if(directonly && subnet->owner != via) {
-               return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+               route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+               return;
        }
 
        if(via && packet->len > MAX(via->mtu, 590) && via != myself) {
@@ -742,11 +751,13 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
        }
 
        if(!subnet->owner->status.reachable) {
-               return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+               route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+               return;
        }
 
        if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
-               return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+               route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+               return;
        }
 
        if(decrement_ttl && source != myself && subnet->owner != myself)
@@ -766,7 +777,8 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
        }
 
        if(directonly && subnet->owner != via) {
-               return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+               route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+               return;
        }
 
        if(via && packet->len > MAX(via->mtu, 1294) && via != myself) {