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Handle neighbor solicitation requests without link layer addresses.

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Apparently FreeBSD likes to send out neighbor solicitation requests, even on a
tun interface where this is completely pointless. These requests do not have an
option header containing a link layer address, so the proxy-neighborsol code
was treating these requests as invalid. We now handle such requests, and send
back equally pointless replies, also without a link layer address. This seems
to satisfy FreeBSD.
This commit is contained in:
Guus Sliepen 2009-02-17 14:43:05 +01:00
parent 2327d3f6eb
commit 1c1a67fd93
1 changed files with 27 additions and 11 deletions
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20
src/route.c
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@ -521,6 +521,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
struct nd_opt_hdr opt;
subnet_t *subnet;
uint16_t checksum;
bool has_opt;
struct {
struct in6_addr ip6_src; /* source address */
@ -531,9 +532,11 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
cp();
if(!checklength(source, packet, ether_size + ip6_size + ns_size + opt_size + ETH_ALEN))
if(!checklength(source, packet, ether_size + ip6_size + ns_size))
return;
has_opt = packet->len >= ether_size + ip6_size + ns_size + opt_size + ETH_ALEN;
if(source != myself) {
ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got neighbor solicitation request from %s (%s) while in router mode!"), source->name, source->hostname);
return;
@ -543,6 +546,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
memcpy(&ip6, packet->data + ether_size, ip6_size);
memcpy(&ns, packet->data + ether_size + ip6_size, ns_size);
if(has_opt)
memcpy(&opt, packet->data + ether_size + ip6_size + ns_size, opt_size);
/* First, snatch the source address from the neighbor solicitation packet */
@ -553,7 +557,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
/* Check if this is a valid neighbor solicitation request */
if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR) {
(has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) {
ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request"));
return;
}
@ -562,15 +566,20 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
pseudo.ip6_src = ip6.ip6_src;
pseudo.ip6_dst = ip6.ip6_dst;
if(has_opt)
pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
else
pseudo.length = htonl(ns_size);
pseudo.next = htonl(IPPROTO_ICMPV6);
/* Generate checksum */
checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
checksum = inet_checksum(&ns, ns_size, checksum);
if(has_opt) {
checksum = inet_checksum(&opt, opt_size, checksum);
checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
}
if(checksum) {
ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
@ -608,6 +617,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
ip6.ip6_dst = ip6.ip6_src; /* swap destination and source protocoll address */
ip6.ip6_src = ns.nd_ns_target;
if(has_opt)
memcpy(packet->data + ether_size + ip6_size + ns_size + opt_size, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
ns.nd_ns_cksum = 0;
@ -619,15 +629,20 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
pseudo.ip6_src = ip6.ip6_src;
pseudo.ip6_dst = ip6.ip6_dst;
if(has_opt)
pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
else
pseudo.length = htonl(ns_size);
pseudo.next = htonl(IPPROTO_ICMPV6);
/* Generate checksum */
checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
checksum = inet_checksum(&ns, ns_size, checksum);
if(has_opt) {
checksum = inet_checksum(&opt, opt_size, checksum);
checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
}
ns.nd_ns_hdr.icmp6_cksum = checksum;
@ -635,6 +650,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet)
memcpy(packet->data + ether_size, &ip6, ip6_size);
memcpy(packet->data + ether_size + ip6_size, &ns, ns_size);
if(has_opt)
memcpy(packet->data + ether_size + ip6_size + ns_size, &opt, opt_size);
send_packet(source, packet);