From e1de9ca990ea638c7e297c5335be415e44c250c1 Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Fri, 15 Mar 2002 14:41:57 +0000 Subject: [PATCH 1/1] Neighbor solicitation requests now work (I think). --- src/route.c | 89 ++++++++++++++++++++++++----------------------------- 1 file changed, 40 insertions(+), 49 deletions(-) diff --git a/src/route.c b/src/route.c index 0799c48c..097dd13f 100644 --- a/src/route.c +++ b/src/route.c @@ -17,7 +17,7 @@ along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - $Id: route.c,v 1.1.2.32 2002/03/12 14:25:04 guus Exp $ + $Id: route.c,v 1.1.2.33 2002/03/15 14:41:57 guus Exp $ */ #include "config.h" @@ -33,10 +33,8 @@ #else #include #endif -#ifdef NEIGHBORSOL #include #include -#endif #include #include #include @@ -188,14 +186,17 @@ cp return subnet->owner; } -#ifdef NEIGHBORSOL -unsigned short int ipv6_cksum(short int *data, int len, unsigned short int cksum) +unsigned short int inet_checksum(unsigned short int *data, int len, unsigned short int prevsum) { + unsigned long int checksum = prevsum ^ 0xFFFF; + while(len--) - { - cksum += ntohs(*data++); - } - return cksum; + checksum += ntohs(*data++); + + while(checksum >> 16) + checksum = (checksum & 0xFFFF) + (checksum >> 16); + + return checksum ^ 0xFFFF; } void route_neighborsol(vpn_packet_t *packet) @@ -204,7 +205,7 @@ void route_neighborsol(vpn_packet_t *packet) struct nd_neighbor_solicit *ns; struct nd_opt_hdr *opt; subnet_t *subnet; - short int cksum; + short unsigned int checksum; struct { struct in6_addr ip6_src; /* source address */ @@ -215,8 +216,8 @@ void route_neighborsol(vpn_packet_t *packet) cp hdr = (struct ip6_hdr *)(packet->data + 14); - ns = (struct nd_neighbor_solicit *)(packet->data + 14 + sizeof(struct ip6_hdr)); - opt = (struct nd_opt_hdr *)(packet->data + 14 + sizeof(struct ip6_hdr) + sizeof(struct nd_neighbor_solicit)); + ns = (struct nd_neighbor_solicit *)(packet->data + 14 + sizeof(*hdr)); + opt = (struct nd_opt_hdr *)(packet->data + 14 + sizeof(*hdr) + sizeof(*ns)); /* First, snatch the source address from the neighbor solicitation packet */ @@ -234,8 +235,28 @@ cp return; } + /* Create pseudo header */ + + memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); + memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); + pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6); + pseudo.junk[0] = pseudo.junk[1] = pseudo.junk[2] = 0; + pseudo.junk[3] = IPPROTO_ICMPV6; + + /* Generate checksum */ + + checksum = inet_checksum((unsigned short int *)&pseudo, sizeof(pseudo)/2, ~0); + checksum = inet_checksum((unsigned short int *)ns, sizeof(*ns)/2 + 4, checksum); + + if(checksum) + { + if(debug_lvl >= DEBUG_TRAFFIC) + syslog(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request")); + return; + } + /* Check if the IPv6 address exists on the VPN */ -#if 0 + subnet = lookup_subnet_ipv6((ipv6_t *)&ns->nd_ns_target); if(!subnet) @@ -254,35 +275,8 @@ cp if(subnet->owner == myself) return; /* silently ignore */ -#endif - - syslog(LOG_DEBUG, "Neighbor solicitation request with checksum %hx", ntohs(ns->nd_ns_hdr.icmp6_cksum)); - - /* Create pseudo header */ - - memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); - memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); - pseudo.length = htonl(sizeof(*ns)); - pseudo.junk[0] = pseudo.junk[1] = pseudo.junk[2] = 0; - pseudo.junk[3] = IPPROTO_ICMPV6; - - /* Generate checksum */ - - ns->nd_ns_hdr.icmp6_cksum = 0; - - cksum = ipv6_cksum((short int *)&pseudo, sizeof(pseudo)/2, 0); - - syslog(LOG_DEBUG, "Our checksum %hx", cksum); - - cksum = ipv6_cksum((short int *)ns, sizeof(*ns)/2, cksum); - - syslog(LOG_DEBUG, "Our checksum %hx", cksum); - cksum = ipv6_cksum((short int *)opt, sizeof(*opt)/2, cksum); - - syslog(LOG_DEBUG, "Our checksum %hx", cksum); - - /* Create neighbor advertation reply */ + /* Create neighbor advertation reply */ memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */ packet->data[ETHER_ADDR_LEN*2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */ @@ -294,27 +288,26 @@ cp ns->nd_ns_hdr.icmp6_cksum = 0; ns->nd_ns_hdr.icmp6_type = ND_NEIGHBOR_ADVERT; + ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[0] = 0x40; /* Set solicited flag */ + ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[1] = ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[2] = ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[3] = 0; opt->nd_opt_type = ND_OPT_TARGET_LINKADDR; /* Create pseudo header */ memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); - pseudo.length = htonl(sizeof(struct icmp6_hdr)); + pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6); pseudo.junk[0] = pseudo.junk[1] = pseudo.junk[2] = 0; pseudo.junk[3] = IPPROTO_ICMPV6; /* Generate checksum */ - cksum = ipv6_cksum((short int *)&pseudo, sizeof(pseudo)/2, 0); - cksum = ipv6_cksum((short int *)ns, sizeof(*ns)/2, cksum); + checksum = inet_checksum((unsigned short int *)&pseudo, sizeof(pseudo)/2, ~0); + checksum = inet_checksum((unsigned short int *)ns, sizeof(*ns)/2 + 4, checksum); - ns->nd_ns_hdr.icmp6_cksum = htons(cksum); - write_packet(packet); cp } -#endif void route_arp(vpn_packet_t *packet) { @@ -401,13 +394,11 @@ cp break; case 0x86DD: n = route_ipv6(packet); -#ifdef NEIGHBORSOL if(!n && packet->data[0] == 0x33 && packet->data[1] == 0x33 && packet->data[2] == 0xff) { route_neighborsol(packet); return; } -#endif break; case 0x0806: route_arp(packet); -- 2.20.1