X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Froute.c;h=d7c4c872fe27fed160af90458ea403ecd66e4387;hb=a8a3a2c8ceb19bcb6c2c3ef0647c94d7d0624b7a;hp=27851469555040a0d0b8326410494194262b0d60;hpb=04fc19112da5e7fcefefcf6e490987cdcfb6f620;p=tinc

diff --git a/src/route.c b/src/route.c
index 27851469..d7c4c872 100644
--- a/src/route.c
+++ b/src/route.c
@@ -164,7 +164,7 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		/* Found it */
 		uint16_t oldmss = DATA(packet)[start + 22 + i] << 8 | DATA(packet)[start + 23 + i];
 		uint16_t newmss = mtu - start - 20;
-		uint16_t csum = DATA(packet)[start + 16] << 8 | DATA(packet)[start + 17];
+		uint32_t csum = DATA(packet)[start + 16] << 8 | DATA(packet)[start + 17];
 
 		if(oldmss <= newmss)
 			break;
@@ -175,11 +175,13 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		DATA(packet)[start + 22 + i] = newmss >> 8;
 		DATA(packet)[start + 23 + i] = newmss & 0xff;
 		csum ^= 0xffff;
-		csum -= oldmss;
+		csum += oldmss ^ 0xffff;
 		csum += newmss;
+		csum = (csum & 0xffff) + (csum >> 16);
+		csum += csum >> 16;
 		csum ^= 0xffff;
 		DATA(packet)[start + 16] = csum >> 8;
-		DATA(packet)[start + 17] = csum & 0xff;
+		DATA(packet)[start + 17] = csum;
 		break;
 	}
 }
@@ -782,15 +784,13 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	if(subnet->owner == myself)
 		return;                                          /* silently ignore */
 
-	memcpy(DATA(packet), DATA(packet) + ETH_ALEN, ETH_ALEN); /* copy destination address */
-	DATA(packet)[ETH_ALEN * 2 - 1] ^= 0xFF;                  /* mangle source address so it looks like it's not from us */
-
 	memcpy(&addr, arp.arp_tpa, sizeof addr);                 /* save protocol addr */
 	memcpy(arp.arp_tpa, arp.arp_spa, sizeof addr);           /* swap destination and source protocol address */
 	memcpy(arp.arp_spa, &addr, sizeof addr);                 /* ... */
 
 	memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN);              /* set target hard/proto addr */
-	memcpy(arp.arp_sha, DATA(packet) + ETH_ALEN, ETH_ALEN);  /* add fake source hard addr */
+	memcpy(arp.arp_sha, DATA(packet) + ETH_ALEN, ETH_ALEN);  /* set source hard/proto addr */
+	arp.arp_sha[ETH_ALEN - 1] ^= 0xFF;                       /* for consistency with route_packet() */
 	arp.arp_op = htons(ARPOP_REPLY);
 
 	/* Copy structs on stack back to packet */
@@ -902,7 +902,7 @@ static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
 			if(!checklength(source, packet, ethlen + ip_size))
 				return false;
 
-			if(DATA(packet)[ethlen + 8] < 1) {
+			if(DATA(packet)[ethlen + 8] <= 1) {
 				if(DATA(packet)[ethlen + 11] != IPPROTO_ICMP || DATA(packet)[ethlen + 32] != ICMP_TIME_EXCEEDED)
 					route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
 				return false;
@@ -925,7 +925,7 @@ static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
 			if(!checklength(source, packet, ethlen + ip6_size))
 				return false;
 
-			if(DATA(packet)[ethlen + 7] < 1) {
+			if(DATA(packet)[ethlen + 7] <= 1) {
 				if(DATA(packet)[ethlen + 6] != IPPROTO_ICMPV6 || DATA(packet)[ethlen + 40] != ICMP6_TIME_EXCEEDED)
 					route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
 				return false;