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/*
Copyright (c) 2006, 2007 Dmitry Butskoy
<buc@citadel.stu.neva.ru>
License: GPL v2 or any later
See COPYING for the status of this software.
*/
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <poll.h>
#include <netinet/icmp6.h>
#include <netinet/ip_icmp.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include "traceroute.h"
static sockaddr_any dest_addr = {{ 0, }, };
static uint16_t seq = 1;
static uint16_t ident = 0;
static char *data;
static size_t *length_p;
static int icmp_sk = -1;
static int last_ttl = 0;
static int raw = 0;
static int dgram = 0;
static CLIF_option icmp_options[] = {
{ 0, "raw", 0, "Use raw sockets way only. Default is try this way "
"first (probably not allowed for unprivileged users), "
"then try dgram",
CLIF_set_flag, &raw, 0, CLIF_EXCL },
{ 0, "dgram", 0, "Use dgram sockets way only. May be not implemented "
"by old kernels or restricted by sysadmins",
CLIF_set_flag, &dgram, 0, CLIF_EXCL },
CLIF_END_OPTION
};
static int icmp_init (const sockaddr_any *dest,
unsigned int port_seq, size_t *packet_len_p) {
int i;
int af = dest->sa.sa_family;
int protocol;
dest_addr = *dest;
dest_addr.sin.sin_port = 0;
if (port_seq) seq = port_seq;
length_p = packet_len_p;
if (*length_p < sizeof (struct icmphdr))
*length_p = sizeof (struct icmphdr);
data = malloc (*length_p);
if (!data) error ("malloc");
for (i = sizeof (struct icmphdr); i < *length_p; i++)
data[i] = 0x40 + (i & 0x3f);
protocol = (af == AF_INET) ? IPPROTO_ICMP : IPPROTO_ICMPV6;
if (!raw) {
icmp_sk = socket (af, SOCK_DGRAM, protocol);
if (icmp_sk < 0 && dgram)
error ("socket");
}
if (!dgram) {
int raw_sk = socket (af, SOCK_RAW, protocol);
if (raw_sk < 0) {
if (raw || icmp_sk < 0)
error_or_perm ("socket");
dgram = 1;
} else {
/* prefer the traditional "raw" way when possible */
close (icmp_sk);
icmp_sk = raw_sk;
}
}
tune_socket (icmp_sk);
/* Don't want to catch packets from another hosts */
if (raw_can_connect () &&
connect (icmp_sk, &dest_addr.sa, sizeof (dest_addr)) < 0
) error ("connect");
use_recverr (icmp_sk);
if (dgram) {
sockaddr_any addr;
socklen_t len = sizeof (addr);
if (getsockname (icmp_sk, &addr.sa, &len) < 0)
error ("getsockname");
ident = ntohs (addr.sin.sin_port); /* both IPv4 and IPv6 */
} else
ident = getpid () & 0xffff;
add_poll (icmp_sk, POLLIN | POLLERR);
return 0;
}
static void icmp_send_probe (probe *pb, int ttl) {
int af = dest_addr.sa.sa_family;
if (ttl != last_ttl) {
set_ttl (icmp_sk, ttl);
last_ttl = ttl;
}
if (af == AF_INET) {
struct icmp *icmp = (struct icmp *) data;
icmp->icmp_type = ICMP_ECHO;
icmp->icmp_code = 0;
icmp->icmp_cksum = 0;
icmp->icmp_id = htons (ident);
icmp->icmp_seq = htons (seq);
icmp->icmp_cksum = in_csum (data, *length_p);
}
else if (af == AF_INET6) {
struct icmp6_hdr *icmp6 = (struct icmp6_hdr *) data;
icmp6->icmp6_type = ICMP6_ECHO_REQUEST;
icmp6->icmp6_code = 0;
icmp6->icmp6_cksum = 0;
icmp6->icmp6_id = htons (ident);
icmp6->icmp6_seq = htons(seq);
/* icmp6->icmp6_cksum always computed by kernel internally */
}
pb->send_time = get_time ();
if (do_send (icmp_sk, data, *length_p, &dest_addr) < 0) {
pb->send_time = 0;
return;
}
pb->seq = seq;
seq++;
return;
}
static probe *icmp_check_reply (int sk, int err, sockaddr_any *from,
char *buf, size_t len) {
int af = dest_addr.sa.sa_family;
int type;
uint16_t recv_id, recv_seq;
probe *pb;
if (len < sizeof (struct icmphdr))
return NULL;
if (af == AF_INET) {
struct icmp *icmp = (struct icmp *) buf;
type = icmp->icmp_type;
recv_id = ntohs (icmp->icmp_id);
recv_seq = ntohs (icmp->icmp_seq);
}
else { /* AF_INET6 */
struct icmp6_hdr *icmp6 = (struct icmp6_hdr *) buf;
type = icmp6->icmp6_type;
recv_id = ntohs (icmp6->icmp6_id);
recv_seq = ntohs (icmp6->icmp6_seq);
}
if (recv_id != ident)
return NULL;
pb = probe_by_seq (recv_seq);
if (!pb) return NULL;
if (!err) {
if (!(af == AF_INET && type == ICMP_ECHOREPLY) &&
!(af == AF_INET6 && type == ICMP6_ECHO_REPLY)
) return NULL;
pb->final = 1;
}
return pb;
}
static void icmp_recv_probe (int sk, int revents) {
if (!(revents & (POLLIN | POLLERR)))
return;
recv_reply (sk, !!(revents & POLLERR), icmp_check_reply);
}
static void icmp_expire_probe (probe *pb) {
probe_done (pb);
}
static tr_module icmp_ops = {
.name = "icmp",
.init = icmp_init,
.send_probe = icmp_send_probe,
.recv_probe = icmp_recv_probe,
.expire_probe = icmp_expire_probe,
.options = icmp_options,
};
TR_MODULE (icmp_ops);
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