From 428482d86f860d1fb09de722c1b6576ec2eef1ce Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Mon, 4 Jun 2001 11:14:35 +0000 Subject: [PATCH] Added proxy-arp support. No more ifconfig -arp needed. Works like a charm under FreeBSD now :). --- src/route.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 75 insertions(+), 3 deletions(-) diff --git a/src/route.c b/src/route.c index 1b6336dc..3d488874 100644 --- a/src/route.c +++ b/src/route.c @@ -17,21 +17,25 @@ along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - $Id: route.c,v 1.1.2.9 2001/05/28 08:21:43 guus Exp $ + $Id: route.c,v 1.1.2.10 2001/06/04 11:14:35 guus Exp $ */ #include "config.h" #ifdef HAVE_FREEBSD #include -#else - #include #endif +#include +#include +#include +#include #include #include #include #include "net.h" +#include "net/ethernet.h" +#include "netinet/if_ether.h" #include "connection.h" #include "subnet.h" #include "route.h" @@ -133,6 +137,71 @@ cp return NULL; } +void route_arp(vpn_packet_t *packet) +{ + struct ether_arp *arp; + subnet_t *subnet; + unsigned char ipbuf[4]; + ipv4_t dest; +cp + /* This routine generates replies to ARP requests. + You don't need to set NOARP flag on the interface anymore (which is broken on FreeBSD). + Most of the code here is taken from choparp.c by Takamichi Tateoka (tree@mma.club.uec.ac.jp) + */ + + arp = (struct ether_arp *)(packet->data + 14); + + /* Check if this is a valid ARP request */ + + if(ntohs(arp->arp_hrd) != ARPHRD_ETHER || + ntohs(arp->arp_pro) != ETHERTYPE_IP || + (int) (arp->arp_hln) != ETHER_ADDR_LEN || + (int) (arp->arp_pln) != 4 || + ntohs(arp->arp_op) != ARPOP_REQUEST ) + { + if(debug_lvl > DEBUG_TRAFFIC) + { + syslog(LOG_WARNING, _("Cannot route packet: received unknown type ARP request")); + } + return; + } + + /* Check if the IP address exists on the VPN */ + + dest = ntohl(*((unsigned long*)(arp->arp_tpa))); + subnet = lookup_subnet_ipv4(&dest); + + if(!subnet) + { + if(debug_lvl >= DEBUG_TRAFFIC) + { + syslog(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"), + arp->arp_tpa[0], arp->arp_tpa[1], arp->arp_tpa[2], arp->arp_tpa[3]); + } + + return; + } + + /* Check if it is for our own subnet */ + + if(subnet->owner == myself) + return; /* silently ignore */ + + 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(ipbuf, arp->arp_tpa, 4); /* save protocol addr */ + memcpy(arp->arp_tpa, arp->arp_spa, 4); /* swap destination and source protocol address */ + memcpy(arp->arp_spa, ipbuf, 4); /* ... */ + + memcpy(arp->arp_tha, arp->arp_sha, 10); /* set target hard/proto addr */ + memcpy(arp->arp_sha, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* add fake source hard addr */ + arp->arp_op = htons(ARPOP_REPLY); + + accept_packet(packet); +cp +} + void route_outgoing(vpn_packet_t *packet) { unsigned short int type; @@ -153,6 +222,9 @@ cp case 0x86DD: cl = route_ipv6(packet); break; + case 0x0806: + route_arp(packet); + return; default: if(debug_lvl >= DEBUG_TRAFFIC) { -- 2.20.1