From 7d21a8d1c7fd8909fe02385dbb4717c074db4648 Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Sat, 29 Mar 2003 21:51:21 +0000 Subject: [PATCH] - Speed up checksumming - If a destination is not found in the subnet list or the destination node is unreachable, respond with an appropiate ICMP message. --- src/route.c | 204 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 181 insertions(+), 23 deletions(-) diff --git a/src/route.c b/src/route.c index ff84ee98..00aa4863 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 1.1.2.46 2002/09/09 22:33:16 guus Exp $ + $Id: route.c,v 1.1.2.47 2003/03/29 21:51:21 guus Exp $ */ #include "config.h" @@ -36,6 +36,8 @@ #ifdef HAVE_NETINET_IN_SYSTM_H #include #endif +#include +#include #include #include #include @@ -67,6 +69,34 @@ int priorityinheritance = 0; int macexpire = 600; subnet_t mymac; +/* RFC 1071 */ + +uint16_t inet_checksum(void *data, int len, uint16_t prevsum) +{ + uint16_t *p = data; + uint32_t checksum = prevsum ^ 0xFFFF; + + len /= 2; + + while(len--) + checksum += *p++; + + while(checksum >> 16) + checksum = (checksum & 0xFFFF) + (checksum >> 16); + + return ~checksum; +} + +int ratelimit(void) { + static time_t lasttime = 0; + + if(lasttime == now) + return 1; + + lasttime = now; + return 0; +} + void learn_mac(mac_t *address) { subnet_t *subnet; @@ -151,6 +181,67 @@ node_t *route_mac(vpn_packet_t *packet) return NULL; } +/* RFC 792 */ + +void route_ipv4_unreachable(vpn_packet_t *packet, uint8_t code) +{ + struct ip *hdr; + struct icmp *icmp; + + struct in_addr ip_src; + struct in_addr ip_dst; + uint32_t oldlen; + + if(ratelimit()) + return; + + cp(); + + hdr = (struct ip *)(packet->data + 14); + icmp = (struct icmp *)(packet->data + 14 + 20); + + /* Remember original source and destination */ + + memcpy(&ip_src, &hdr->ip_src, 4); + memcpy(&ip_dst, &hdr->ip_dst, 4); + oldlen = packet->len - 14; + + if(oldlen >= IP_MSS - sizeof(*hdr) - sizeof(struct icmphdr)) + oldlen = IP_MSS - sizeof(*hdr) - sizeof(struct icmphdr); + + /* Copy first part of original contents to ICMP message */ + + memmove(&icmp->icmp_ip, hdr, oldlen); + + /* Fill in IPv4 header */ + + hdr->ip_v = 4; + hdr->ip_hl = sizeof(*hdr) / 4; + hdr->ip_tos = 0; + hdr->ip_len = htons(20 + 8 + oldlen); + hdr->ip_id = 0; + hdr->ip_off = 0; + hdr->ip_ttl = 255; + hdr->ip_p = IPPROTO_ICMP; + hdr->ip_sum = 0; + memcpy(&hdr->ip_src, &ip_dst, 4); + memcpy(&hdr->ip_dst, &ip_src, 4); + + hdr->ip_sum = inet_checksum(hdr, 20, ~0); + + /* Fill in ICMP header */ + + icmp->icmp_type = ICMP_DEST_UNREACH; + icmp->icmp_code = code; + icmp->icmp_cksum = 0; + + icmp->icmp_cksum = inet_checksum(icmp, 8 + oldlen, ~0); + + packet->len = 14 + 20 + 8 + oldlen; + + write_packet(packet); +} + node_t *route_ipv4(vpn_packet_t *packet) { subnet_t *subnet; @@ -169,12 +260,86 @@ node_t *route_ipv4(vpn_packet_t *packet) packet->data[33]); } + route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN); return NULL; } + + if(!subnet->owner->status.reachable) + route_ipv4_unreachable(packet, ICMP_NET_UNREACH); return subnet->owner; } +/* RFC 2463 */ + +void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code) +{ + struct ip6_hdr *hdr; + struct icmp6_hdr *icmp; + uint16_t checksum; + + struct { + struct in6_addr ip6_src; /* source address */ + struct in6_addr ip6_dst; /* destination address */ + uint32_t length; + uint32_t next; + } pseudo; + + if(ratelimit()) + return; + + cp(); + + hdr = (struct ip6_hdr *)(packet->data + 14); + icmp = (struct icmp6_hdr *)(packet->data + 14 + sizeof(*hdr)); + + /* Remember original source and destination */ + + memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); + memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); + pseudo.length = ntohs(hdr->ip6_plen) + sizeof(*hdr); + + if(pseudo.length >= IP_MSS - sizeof(*hdr) - sizeof(*icmp)) + pseudo.length = IP_MSS - sizeof(*hdr) - sizeof(*icmp); + + /* Copy first part of original contents to ICMP message */ + + memmove(((char *)icmp) + sizeof(*icmp), hdr, pseudo.length); + + /* Fill in IPv6 header */ + + hdr->ip6_flow = htonl(0x60000000UL); + hdr->ip6_plen = htons(sizeof(*icmp) + pseudo.length); + hdr->ip6_nxt = IPPROTO_ICMPV6; + hdr->ip6_hlim = 255; + memcpy(&hdr->ip6_dst, &pseudo.ip6_src, 16); + memcpy(&hdr->ip6_src, &pseudo.ip6_dst, 16); + + /* Fill in ICMP header */ + + icmp->icmp6_type = ICMP6_DST_UNREACH; + icmp->icmp6_code = code; + icmp->icmp6_cksum = 0; + + /* Create pseudo header */ + + memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); + memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); + pseudo.length = htonl(sizeof(*icmp) + pseudo.length); + pseudo.next = htonl(IPPROTO_ICMPV6); + + /* Generate checksum */ + + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(icmp, ntohl(pseudo.length), checksum); + + icmp->icmp6_cksum = checksum; + + packet->len = 14 + sizeof(*hdr) + ntohl(pseudo.length); + + write_packet(packet); +} + node_t *route_ipv6(vpn_packet_t *packet) { subnet_t *subnet; @@ -195,25 +360,18 @@ node_t *route_ipv6(vpn_packet_t *packet) ntohs(*(uint16_t *) & packet->data[50]), ntohs(*(uint16_t *) & packet->data[52])); } + route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_ADDR); return NULL; } + if(!subnet->owner->status.reachable) + route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_NOROUTE); + return subnet->owner; } -uint16_t inet_checksum(uint16_t *data, int len, uint16_t prevsum) -{ - uint32_t checksum = prevsum ^ 0xFFFF; - - while(len--) - checksum += ntohs(*data++); - - while(checksum >> 16) - checksum = (checksum & 0xFFFF) + (checksum >> 16); - - return checksum ^ 0xFFFF; -} +/* RFC 2461 */ void route_neighborsol(vpn_packet_t *packet) { @@ -227,7 +385,7 @@ void route_neighborsol(vpn_packet_t *packet) struct in6_addr ip6_src; /* source address */ struct in6_addr ip6_dst; /* destination address */ uint32_t length; - uint8_t junk[4]; + uint32_t next; } pseudo; cp(); @@ -255,13 +413,12 @@ void route_neighborsol(vpn_packet_t *packet) 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; + pseudo.next = htonl(IPPROTO_ICMPV6); /* Generate checksum */ - checksum = inet_checksum((uint16_t *) & pseudo, sizeof(pseudo) / 2, ~0); - checksum = inet_checksum((uint16_t *) ns, sizeof(*ns) / 2 + 4, checksum); + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); if(checksum) { if(debug_lvl >= DEBUG_TRAFFIC) @@ -317,19 +474,20 @@ void route_neighborsol(vpn_packet_t *packet) 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; + pseudo.next = htonl(IPPROTO_ICMPV6); /* Generate checksum */ - checksum = inet_checksum((uint16_t *) & pseudo, sizeof(pseudo) / 2, ~0); - checksum = inet_checksum((uint16_t *) ns, sizeof(*ns) / 2 + 4, checksum); + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); - ns->nd_ns_hdr.icmp6_cksum = htons(checksum); + ns->nd_ns_hdr.icmp6_cksum = checksum; write_packet(packet); } +/* RFC 826 */ + void route_arp(vpn_packet_t *packet) { struct ether_arp *arp; -- 2.20.1