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- /*
- * tracepath.c
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- *
- * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
- */
- #include <asm/types.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <sys/socket.h>
- #include <linux/errqueue.h>
- #include <errno.h>
- #include <string.h>
- #include <netdb.h>
- #include <netinet/in.h>
- #include <resolv.h>
- #include <sys/time.h>
- #include <sys/uio.h>
- #include <arpa/inet.h>
- #include <signal.h>
- struct hhistory
- {
- int hops;
- struct timeval sendtime;
- };
-
- struct hhistory his[64];
- int hisptr;
-
- struct sockaddr_in target;
- __u16 base_port;
-
- const int overhead = 28;
- int mtu = 65535;
- int hops_to = -1;
- int hops_from = -1;
- int no_resolve = 0;
-
- struct probehdr
- {
- __u32 ttl;
- struct timeval tv;
- };
-
- void data_wait(int fd)
- {
- fd_set fds;
- struct timeval tv;
- FD_ZERO(&fds);
- FD_SET(fd, &fds);
- tv.tv_sec = 1;
- tv.tv_usec = 0;
- select(fd+1, &fds, NULL, NULL, &tv);
- }
-
- int recverr(int fd, int ttl)
- {
- int res;
- struct probehdr rcvbuf;
- char cbuf[512];
- struct iovec iov;
- struct msghdr msg;
- struct cmsghdr *cmsg;
- struct sock_extended_err *e;
- struct sockaddr_in addr;
- struct timeval tv;
- struct timeval *rettv;
- int slot;
- int rethops;
- int sndhops;
- int progress = -1;
- int broken_router;
-
- restart:
- memset(&rcvbuf, -1, sizeof(rcvbuf));
- iov.iov_base = &rcvbuf;
- iov.iov_len = sizeof(rcvbuf);
- msg.msg_name = (__u8*)&addr;
- msg.msg_namelen = sizeof(addr);
- msg.msg_iov = &iov;
- msg.msg_iovlen = 1;
- msg.msg_flags = 0;
- msg.msg_control = cbuf;
- msg.msg_controllen = sizeof(cbuf);
-
- gettimeofday(&tv, NULL);
- res = recvmsg(fd, &msg, MSG_ERRQUEUE);
- if (res < 0) {
- if (errno == EAGAIN)
- return progress;
- goto restart;
- }
-
- progress = mtu;
-
- rethops = -1;
- sndhops = -1;
- e = NULL;
- rettv = NULL;
- slot = ntohs(addr.sin_port) - base_port;
- if (slot>=0 && slot < 63 && his[slot].hops) {
- sndhops = his[slot].hops;
- rettv = &his[slot].sendtime;
- his[slot].hops = 0;
- }
- broken_router = 0;
- if (res == sizeof(rcvbuf)) {
- if (rcvbuf.ttl == 0 || rcvbuf.tv.tv_sec == 0) {
- broken_router = 1;
- } else {
- sndhops = rcvbuf.ttl;
- rettv = &rcvbuf.tv;
- }
- }
-
- for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
- if (cmsg->cmsg_level == SOL_IP) {
- if (cmsg->cmsg_type == IP_RECVERR) {
- e = (struct sock_extended_err *) CMSG_DATA(cmsg);
- } else if (cmsg->cmsg_type == IP_TTL) {
- rethops = *(int*)CMSG_DATA(cmsg);
- } else {
- printf("cmsg:%d\n ", cmsg->cmsg_type);
- }
- }
- }
- if (e == NULL) {
- printf("no info\n");
- return 0;
- }
- if (e->ee_origin == SO_EE_ORIGIN_LOCAL) {
- printf("%2d?: %-15s ", ttl, "[LOCALHOST]");
- } else if (e->ee_origin == SO_EE_ORIGIN_ICMP) {
- char abuf[128];
- struct sockaddr_in *sin = (struct sockaddr_in*)(e+1);
-
- inet_ntop(AF_INET, &sin->sin_addr, abuf, sizeof(abuf));
-
- if (sndhops>0)
- printf("%2d: ", sndhops);
- else
- printf("%2d?: ", ttl);
-
- if(!no_resolve) {
- char fabuf[256];
- struct hostent *h;
- fflush(stdout);
- h = gethostbyaddr((char *) &sin->sin_addr, sizeof(sin->sin_addr), AF_INET);
- snprintf(fabuf, sizeof(fabuf), "%s (%s)", h ? h->h_name : abuf, abuf);
- printf("%-52s ", fabuf);
- } else {
- printf("%-15s ", abuf);
- }
- }
-
- if (rethops>=0) {
- if (rethops<=64)
- rethops = 65-rethops;
- else if (rethops<=128)
- rethops = 129-rethops;
- else
- rethops = 256-rethops;
- if (sndhops>=0 && rethops != sndhops)
- printf("asymm %2d ", rethops);
- else if (sndhops<0 && rethops != ttl)
- printf("asymm %2d ", rethops);
- }
-
- if (rettv) {
- int diff = (tv.tv_sec-rettv->tv_sec)*1000000+(tv.tv_usec-rettv->tv_usec);
- printf("%3d.%03dms ", diff/1000, diff%1000);
- if (broken_router)
- printf("(This broken router returned corrupted payload) ");
- }
-
- switch (e->ee_errno) {
- case ETIMEDOUT:
- printf("\n");
- break;
- case EMSGSIZE:
- printf("pmtu %d\n", e->ee_info);
- mtu = e->ee_info;
- progress = mtu;
- break;
- case ECONNREFUSED:
- printf("reached\n");
- hops_to = sndhops<0 ? ttl : sndhops;
- hops_from = rethops;
- return 0;
- case EPROTO:
- printf("!P\n");
- return 0;
- case EHOSTUNREACH:
- if (e->ee_origin == SO_EE_ORIGIN_ICMP &&
- e->ee_type == 11 &&
- e->ee_code == 0) {
- printf("\n");
- break;
- }
- printf("!H\n");
- return 0;
- case ENETUNREACH:
- printf("!N\n");
- return 0;
- case EACCES:
- printf("!A\n");
- return 0;
- default:
- printf("\n");
- errno = e->ee_errno;
- perror("NET ERROR");
- return 0;
- }
- goto restart;
- }
-
- int probe_ttl(int fd, int ttl)
- {
- int i;
- char sndbuf[mtu];
- struct probehdr *hdr = (struct probehdr*)sndbuf;
-
- memset(sndbuf,0,mtu);
-
- restart:
- for (i=0; i<10; i++) {
- int res;
-
- hdr->ttl = ttl;
- target.sin_port = htons(base_port + hisptr);
- gettimeofday(&hdr->tv, NULL);
- his[hisptr].hops = ttl;
- his[hisptr].sendtime = hdr->tv;
- if (sendto(fd, sndbuf, mtu-overhead, 0, (struct sockaddr*)&target, sizeof(target)) > 0)
- break;
- res = recverr(fd, ttl);
- his[hisptr].hops = 0;
- if (res==0)
- return 0;
- if (res > 0)
- goto restart;
- }
- hisptr = (hisptr + 1)&63;
-
- if (i<10) {
- data_wait(fd);
- if (recv(fd, sndbuf, sizeof(sndbuf), MSG_DONTWAIT) > 0) {
- printf("%2d?: reply received 8)\n", ttl);
- return 0;
- }
- return recverr(fd, ttl);
- }
-
- printf("%2d: send failed\n", ttl);
- return 0;
- }
-
- static void usage(void) __attribute((noreturn));
-
- static void usage(void)
- {
- fprintf(stderr, "Usage: tracepath [-n] <destination>[/<port>]\n");
- exit(-1);
- }
-
- int
- oldmain(int argc, char **argv)
- {
- struct hostent *he;
- int fd;
- int on;
- int ttl;
- char *p;
- int ch;
-
- while ((ch = getopt(argc, argv, "nh?")) != EOF) {
- switch(ch) {
- case 'n':
- no_resolve = 1;
- break;
- default: ;
- }
- }
-
- argc -= optind;
- argv += optind;
-
- if (argc != 1)
- usage();
-
-
- fd = socket(AF_INET, SOCK_DGRAM, 0);
- if (fd < 0) {
- perror("socket");
- exit(1);
- }
- target.sin_family = AF_INET;
-
- p = strchr(argv[0], '/');
- if (p) {
- *p = 0;
- base_port = atoi(p+1);
- } else
- base_port = 44444;
- he = gethostbyname(argv[0]);
- if (he == NULL) {
- herror("gethostbyname");
- exit(1);
- }
- memcpy(&target.sin_addr, he->h_addr, 4);
-
- on = IP_PMTUDISC_DO;
- if (setsockopt(fd, SOL_IP, IP_MTU_DISCOVER, &on, sizeof(on))) {
- perror("IP_MTU_DISCOVER");
- exit(1);
- }
- on = 1;
- if (setsockopt(fd, SOL_IP, IP_RECVERR, &on, sizeof(on))) {
- perror("IP_RECVERR");
- exit(1);
- }
- if (setsockopt(fd, SOL_IP, IP_RECVTTL, &on, sizeof(on))) {
- perror("IP_RECVTTL");
- exit(1);
- }
-
- for (ttl=1; ttl<32; ttl++) {
- int res;
- int i;
-
- on = ttl;
- if (setsockopt(fd, SOL_IP, IP_TTL, &on, sizeof(on))) {
- perror("IP_TTL");
- exit(1);
- }
-
- for (i=0; i<3; i++) {
- res = probe_ttl(fd, ttl);
- if (res == 0)
- goto done;
- if (res > 0)
- break;
- }
-
- if (res < 0)
- printf("%2d: no reply\n", ttl);
- }
- printf(" Too many hops: pmtu %d\n", mtu);
- done:
- printf(" Resume: pmtu %d ", mtu);
- if (hops_to>=0)
- printf("hops %d ", hops_to);
- if (hops_from>=0)
- printf("back %d ", hops_from);
- printf("\n");
- exit(0);
- }
- extern char** environ;
- int main()
- {
- char *args[4];
- char ipaddr[256];
- char *myenv[1]={0};
- /* Point environment to a sane place */
- environ=myenv;
- signal(SIGPIPE, SIG_DFL);
- printf("Second stage OK. Which ipaddr should I try ?\n");
- scanf("%s", ipaddr);
-
- /* Prepare command line */
- args[0]="tracepath";
- args[1]="-n";
- args[2]=ipaddr;
- args[3]=0;
- /* Call original main() */
- oldmain(3, args);
- }
-