27329d23aa
- Call sessionshutdown() when a tunnel is dropped rather than sessionkill() to ensure that RADIUS stop records are sent. - Cleanup: make a bunch of global functions/variables static.
91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
// L2TPNS: icmp
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char const *cvs_id_icmp = "$Id: icmp.c,v 1.5 2004/11/16 07:54:32 bodea Exp $";
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <asm/types.h>
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#include <linux/ip.h>
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#include <linux/icmp.h>
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#include <stdio.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <memory.h>
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#include "l2tpns.h"
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static __u16 _checksum(unsigned char *addr, int count);
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void host_unreachable(ipt destination, u16 id, ipt source, char *packet, int packet_len)
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{
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char buf[128] = {0};
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struct iphdr *iph;
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struct icmphdr *icmp;
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char *data;
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int len = 0, on = 1, icmp_socket;
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struct sockaddr_in whereto = {0};
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if ((icmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
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return;
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setsockopt(icmp_socket, IPPROTO_IP, IP_HDRINCL, (char *)&on, sizeof(on));
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whereto.sin_addr.s_addr = destination;
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whereto.sin_family = AF_INET;
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iph = (struct iphdr *)(buf);
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len = sizeof(struct iphdr);
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icmp = (struct icmphdr *)(buf + len);
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len += sizeof(struct icmphdr);
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data = (char *)(buf + len);
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len += (packet_len < 64) ? packet_len : 64;
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memcpy(data, packet, (packet_len < 64) ? packet_len : 64);
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iph->tos = 0;
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iph->id = id;
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iph->frag_off = 0;
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iph->ttl = 30;
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iph->check = 0;
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iph->version = 4;
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iph->ihl = 5;
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iph->protocol = 1;
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iph->check = 0;
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iph->daddr = destination;
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iph->saddr = source;
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iph->tot_len = ntohs(len);
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icmp->type = ICMP_DEST_UNREACH;
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icmp->code = ICMP_HOST_UNREACH;
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icmp->checksum = _checksum((char *)icmp, sizeof(struct icmphdr) + ((packet_len < 64) ? packet_len : 64));
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iph->check = _checksum((char *)iph, sizeof(struct iphdr));
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sendto(icmp_socket, (char *)buf, len, 0, (struct sockaddr *)&whereto, sizeof(struct sockaddr));
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close(icmp_socket);
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}
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static __u16 _checksum(unsigned char *addr, int count)
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{
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register long sum = 0;
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for (; count > 1; count -= 2)
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{
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sum += ntohs(*(u32 *)addr);
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addr += 2;
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}
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if (count > 1) sum += *(unsigned char *)addr;
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// take only 16 bits out of the 32 bit sum and add up the carries
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while (sum >> 16)
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sum = (sum & 0xFFFF) + (sum >> 16);
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// one's complement the result
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sum = ~sum;
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return htons((u16) sum);
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}
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