l2tpns/icmp.c
David Parrish c239d4b228 * Wed Jun 23 2004 David Parrish <david@dparrish.com> 2.0.0
- Major release
- Completely replace active/standby clustering with a new peer-to-peer
  clustering method which allows much greater throughput and is a lot more fault
  tolerant
- Add internal tbf implementation for throttling without relying on tc and
  kernel HTB
- Add support for iBGP and eBGP to advertise routes
- Add cli commands "show cluster", "show bgp", "show ipcache", "show throttle",
  "show tbf", "suspend bgp", "restart bgp", "show user"
- Interception destination must be set per-user
- If SMP machine, allow use of SCHED_FIFO, which should improve performance
- Added config option to send GARP at startup
- Added plugin_become_master and plugin_new_session_master plugin hooks
- Remove useless sessionsendarp(). This isn't needed now that we are using TUN
  instead of TAP.
- ICMP rate limiting so not every unreachable packet is replied with an ICMP
  unreachable message
- mangle table is not required on anything but the cluster master, so slaves
  will drop the mangle table and attempt to unload the ip_conntrack module
- Statically assigned IP addresses (by Radius) work now
- Add -d command-line flag to detach and become a daemon
- Configuration file is now "/etc/l2tpns/startup-config"
- Reduced MIN_IP_SIZE to 0x19 to stop a pile of Short IP warnings
- Resend initial IPCP request until it's acknowleged by the client
- Better radius session cleanup logic
- Many miscellaenous bugfixes and performance enhancements
- Thanks to Michael O'Reilly and Brendan O'Dea for most of these new features
2004-06-23 03:52:24 +00:00

86 lines
2 KiB
C

#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <asm/types.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <stdio.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <memory.h>
#include "l2tpns.h"
__u16 _checksum(unsigned char *addr, int count);
void host_unreachable(ipt destination, u16 id, ipt source, char *packet, int packet_len)
{
char buf[128] = {0};
struct iphdr *iph;
struct icmphdr *icmp;
char *data;
int len = 0, on = 1, icmp_socket;
struct sockaddr_in whereto = {0};
if (!(icmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)))
return;
setsockopt(icmp_socket, IPPROTO_IP, IP_HDRINCL, (char *)&on, sizeof(on));
whereto.sin_addr.s_addr = destination;
whereto.sin_family = AF_INET;
iph = (struct iphdr *)(buf);
len = sizeof(struct iphdr);
icmp = (struct icmphdr *)(buf + len);
len += sizeof(struct icmphdr);
data = (char *)(buf + len);
len += (packet_len < 64) ? packet_len : 64;
memcpy(data, packet, (packet_len < 64) ? packet_len : 64);
iph->tos = 0;
iph->id = id;
iph->frag_off = 0;
iph->ttl = 30;
iph->check = 0;
iph->version = 4;
iph->ihl = 5;
iph->protocol = 1;
iph->check = 0;
iph->daddr = destination;
iph->saddr = source;
iph->tot_len = ntohs(len);
icmp->type = ICMP_DEST_UNREACH;
icmp->code = ICMP_HOST_UNREACH;
icmp->checksum = _checksum((char *)icmp, sizeof(struct icmphdr) + ((packet_len < 64) ? packet_len : 64));
iph->check = _checksum((char *)iph, sizeof(struct iphdr));
sendto(icmp_socket, (char *)buf, len, 0, (struct sockaddr *)&whereto, sizeof(struct sockaddr));
close(icmp_socket);
}
__u16 _checksum(unsigned char *addr, int count)
{
register long sum = 0;
for (; count > 1; count -= 2)
{
sum += ntohs(*(u32 *)addr);
addr += 2;
}
if (count > 1) sum += *(unsigned char *)addr;
// take only 16 bits out of the 32 bit sum and add up the carries
while (sum >> 16)
sum = (sum & 0xFFFF) + (sum >> 16);
// one's complement the result
sum = ~sum;
return htons((u16) sum);
}