X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=4e41cdff7ca6fcb68fc61adffe8b7ac624179596;hp=f42b6a554f6bc5844d7df56a763c7c152ddd800d;hb=0e93f0aa02274481c16fc9f30b795d4f063bd1c3;hpb=024ab44d98883d78cefe2c622cec9831c7f19c13 diff --git a/src/route.c b/src/route.c index f42b6a55..4e41cdff 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 1.1.2.29 2002/03/10 14:04:48 guus Exp $ + $Id: route.c,v 1.1.2.34 2002/03/15 15:08:21 guus Exp $ */ #include "config.h" @@ -33,6 +33,8 @@ #else #include #endif +#include +#include #include #include #include @@ -184,6 +186,131 @@ cp return subnet->owner; } +unsigned short int inet_checksum(unsigned short int *data, int len, unsigned short int prevsum) +{ + unsigned long int checksum = prevsum ^ 0xFFFF; + + while(len--) + checksum += ntohs(*data++); + + while(checksum >> 16) + checksum = (checksum & 0xFFFF) + (checksum >> 16); + + return checksum ^ 0xFFFF; +} + +void route_neighborsol(vpn_packet_t *packet) +{ + struct ip6_hdr *hdr; + struct nd_neighbor_solicit *ns; + struct nd_opt_hdr *opt; + subnet_t *subnet; + short unsigned int checksum; + + struct { + struct in6_addr ip6_src; /* source address */ + struct in6_addr ip6_dst; /* destination address */ + uint32_t length; + uint8_t junk[4]; + } pseudo; + +cp + hdr = (struct ip6_hdr *)(packet->data + 14); + 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 */ + + memcpy(mymac.net.mac.address.x, packet->data + 6, 6); + + /* 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) + { + if(debug_lvl > DEBUG_TRAFFIC) + { + syslog(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request")); + } + 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 */ + + subnet = lookup_subnet_ipv6((ipv6_t *)&ns->nd_ns_target); + + if(!subnet) + { + if(debug_lvl >= DEBUG_TRAFFIC) + { + syslog(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"), + ntohs(ns->nd_ns_target.s6_addr16[0]), ntohs(ns->nd_ns_target.s6_addr16[1]), ntohs(ns->nd_ns_target.s6_addr16[2]), ntohs(ns->nd_ns_target.s6_addr16[3]), + ntohs(ns->nd_ns_target.s6_addr16[4]), ntohs(ns->nd_ns_target.s6_addr16[5]), ntohs(ns->nd_ns_target.s6_addr16[6]), ntohs(ns->nd_ns_target.s6_addr16[7])); + } + + return; + } + + /* Check if it is for our own subnet */ + + if(subnet->owner == myself) + return; /* silently ignore */ + + /* 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 */ + + memcpy(&hdr->ip6_dst, &hdr->ip6_src, 16); /* swap destination and source protocol address */ + memcpy(&hdr->ip6_src, &ns->nd_ns_target, 16); /* ... */ + + memcpy((char *)opt + sizeof(*opt), packet->data + ETHER_ADDR_LEN, 6); /* add fake source hard addr */ + + 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(*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); + + ns->nd_ns_hdr.icmp6_cksum = checksum; + + write_packet(packet); +cp +} + void route_arp(vpn_packet_t *packet) { struct ether_arp *arp; @@ -216,7 +343,7 @@ cp return; } - /* Check if the IP address exists on the VPN */ + /* Check if the IPv4 address exists on the VPN */ subnet = lookup_subnet_ipv4((ipv4_t *)arp->arp_tpa); @@ -269,6 +396,11 @@ cp break; case 0x86DD: n = route_ipv6(packet); + if(!n && packet->data[0] == 0x33 && packet->data[1] == 0x33 && packet->data[2] == 0xff) + { + route_neighborsol(packet); + return; + } break; case 0x0806: route_arp(packet);