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traceroute源码和他的原理是什么?
4.4BSD的traceroute代码
- /*-
- * Copyright (c) 1990, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Van Jacobson.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #ifndef lint
- static char copyright[] =
- "@(#) Copyright (c) 1990, 1993\n\
- The Regents of the University of California. All rights reserved.\n";
- #endif /* not lint */
- #ifndef lint
- static char sccsid[] = "@(#)traceroute.c 8.1 (Berkeley) 6/6/93";
- #endif /* not lint */
- /*
- * traceroute host - trace the route ip packets follow going to "host".
- *
- * Attempt to trace the route an ip packet would follow to some
- * internet host. We find out intermediate hops by launching probe
- * packets with a small ttl (time to live) then listening for an
- * icmp "time exceeded" reply from a gateway. We start our probes
- * with a ttl of one and increase by one until we get an icmp "port
- * unreachable" (which means we got to "host") or hit a max (which
- * defaults to 30 hops & can be changed with the -m flag). Three
- * probes (change with -q flag) are sent at each ttl setting and a
- * line is printed showing the ttl, address of the gateway and
- * round trip time of each probe. If the probe answers come from
- * different gateways, the address of each responding system will
- * be printed. If there is no response within a 5 sec. timeout
- * interval (changed with the -w flag), a "*" is printed for that
- * probe.
- *
- * Probe packets are UDP format. We don't want the destination
- * host to process them so the destination port is set to an
- * unlikely value (if some clod on the destination is using that
- * value, it can be changed with the -p flag).
- *
- * A sample use might be:
- *
- * [yak 71]% traceroute nis.nsf.net.
- * traceroute to nis.nsf.net (35.1.1.48), 30 hops max, 56 byte packet
- * 1 helios.ee.lbl.gov (128.3.112.1) 19 ms 19 ms 0 ms
- * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
- * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 39 ms 19 ms
- * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 39 ms
- * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 39 ms 39 ms 39 ms
- * 6 128.32.197.4 (128.32.197.4) 40 ms 59 ms 59 ms
- * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 59 ms
- * 8 129.140.70.13 (129.140.70.13) 99 ms 99 ms 80 ms
- * 9 129.140.71.6 (129.140.71.6) 139 ms 239 ms 319 ms
- * 10 129.140.81.7 (129.140.81.7) 220 ms 199 ms 199 ms
- * 11 nic.merit.edu (35.1.1.48) 239 ms 239 ms 239 ms
- *
- * Note that lines 2 & 3 are the same. This is due to a buggy
- * kernel on the 2nd hop system -- lbl-csam.arpa -- that forwards
- * packets with a zero ttl.
- *
- * A more interesting example is:
- *
- * [yak 72]% traceroute allspice.lcs.mit.edu.
- * traceroute to allspice.lcs.mit.edu (18.26.0.115), 30 hops max
- * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
- * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 19 ms 19 ms
- * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 19 ms
- * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 19 ms 39 ms 39 ms
- * 5 ccn-nerif22.Berkeley.EDU (128.32.168.22) 20 ms 39 ms 39 ms
- * 6 128.32.197.4 (128.32.197.4) 59 ms 119 ms 39 ms
- * 7 131.119.2.5 (131.119.2.5) 59 ms 59 ms 39 ms
- * 8 129.140.70.13 (129.140.70.13) 80 ms 79 ms 99 ms
- * 9 129.140.71.6 (129.140.71.6) 139 ms 139 ms 159 ms
- * 10 129.140.81.7 (129.140.81.7) 199 ms 180 ms 300 ms
- * 11 129.140.72.17 (129.140.72.17) 300 ms 239 ms 239 ms
- * 12 * * *
- * 13 128.121.54.72 (128.121.54.72) 259 ms 499 ms 279 ms
- * 14 * * *
- * 15 * * *
- * 16 * * *
- * 17 * * *
- * 18 ALLSPICE.LCS.MIT.EDU (18.26.0.115) 339 ms 279 ms 279 ms
- *
- * (I start to see why I'm having so much trouble with mail to
- * MIT.) Note that the gateways 12, 14, 15, 16 & 17 hops away
- * either don't send ICMP "time exceeded" messages or send them
- * with a ttl too small to reach us. 14 - 17 are running the
- * MIT C Gateway code that doesn't send "time exceeded"s. God
- * only knows what's going on with 12.
- *
- * The silent gateway 12 in the above may be the result of a bug in
- * the 4.[23]BSD network code (and its derivatives): 4.x (x <= 3)
- * sends an unreachable message using whatever ttl remains in the
- * original datagram. Since, for gateways, the remaining ttl is
- * zero, the icmp "time exceeded" is guaranteed to not make it back
- * to us. The behavior of this bug is slightly more interesting
- * when it appears on the destination system:
- *
- * 1 helios.ee.lbl.gov (128.3.112.1) 0 ms 0 ms 0 ms
- * 2 lilac-dmc.Berkeley.EDU (128.32.216.1) 39 ms 19 ms 39 ms
- * 3 lilac-dmc.Berkeley.EDU (128.32.216.1) 19 ms 39 ms 19 ms
- * 4 ccngw-ner-cc.Berkeley.EDU (128.32.136.23) 39 ms 40 ms 19 ms
- * 5 ccn-nerif35.Berkeley.EDU (128.32.168.35) 39 ms 39 ms 39 ms
- * 6 csgw.Berkeley.EDU (128.32.133.254) 39 ms 59 ms 39 ms
- * 7 * * *
- * 8 * * *
- * 9 * * *
- * 10 * * *
- * 11 * * *
- * 12 * * *
- * 13 rip.Berkeley.EDU (128.32.131.22) 59 ms ! 39 ms ! 39 ms !
- *
- * Notice that there are 12 "gateways" (13 is the final
- * destination) and exactly the last half of them are "missing".
- * What's really happening is that rip (a Sun-3 running Sun OS3.5)
- * is using the ttl from our arriving datagram as the ttl in its
- * icmp reply. So, the reply will time out on the return path
- * (with no notice sent to anyone since icmp's aren't sent for
- * icmp's) until we probe with a ttl that's at least twice the path
- * length. I.e., rip is really only 7 hops away. A reply that
- * returns with a ttl of 1 is a clue this problem exists.
- * Traceroute prints a "!" after the time if the ttl is <= 1.
- * Since vendors ship a lot of obsolete (DEC's Ultrix, Sun 3.x) or
- * non-standard (HPUX) software, expect to see this problem
- * frequently and/or take care picking the target host of your
- * probes.
- *
- * Other possible annotations after the time are !H, !N, !P (got a host,
- * network or protocol unreachable, respectively), !S or !F (source
- * route failed or fragmentation needed -- neither of these should
- * ever occur and the associated gateway is busted if you see one). If
- * almost all the probes result in some kind of unreachable, traceroute
- * will give up and exit.
- *
- * Notes
- * -----
- * This program must be run by root or be setuid. (I suggest that
- * you *don't* make it setuid -- casual use could result in a lot
- * of unnecessary traffic on our poor, congested nets.)
- *
- * This program requires a kernel mod that does not appear in any
- * system available from Berkeley: A raw ip socket using proto
- * IPPROTO_RAW must interpret the data sent as an ip datagram (as
- * opposed to data to be wrapped in a ip datagram). See the README
- * file that came with the source to this program for a description
- * of the mods I made to /sys/netinet/raw_ip.c. Your mileage may
- * vary. But, again, ANY 4.x (x < 4) BSD KERNEL WILL HAVE TO BE
- * MODIFIED TO RUN THIS PROGRAM.
- *
- * The udp port usage may appear bizarre (well, ok, it is bizarre).
- * The problem is that an icmp message only contains 8 bytes of
- * data from the original datagram. 8 bytes is the size of a udp
- * header so, if we want to associate replies with the original
- * datagram, the necessary information must be encoded into the
- * udp header (the ip id could be used but there's no way to
- * interlock with the kernel's assignment of ip id's and, anyway,
- * it would have taken a lot more kernel hacking to allow this
- * code to set the ip id). So, to allow two or more users to
- * use traceroute simultaneously, we use this task's pid as the
- * source port (the high bit is set to move the port number out
- * of the "likely" range). To keep track of which probe is being
- * replied to (so times and/or hop counts don't get confused by a
- * reply that was delayed in transit), we increment the destination
- * port number before each probe.
- *
- * Don't use this as a coding example. I was trying to find a
- * routing problem and this code sort-of popped out after 48 hours
- * without sleep. I was amazed it ever compiled, much less ran.
- *
- * I stole the idea for this program from Steve Deering. Since
- * the first release, I've learned that had I attended the right
- * IETF working group meetings, I also could have stolen it from Guy
- * Almes or Matt Mathis. I don't know (or care) who came up with
- * the idea first. I envy the originators' perspicacity and I'm
- * glad they didn't keep the idea a secret.
- *
- * Tim Seaver, Ken Adelman and C. Philip Wood provided bug fixes and/or
- * enhancements to the original distribution.
- *
- * I've hacked up a round-trip-route version of this that works by
- * sending a loose-source-routed udp datagram through the destination
- * back to yourself. Unfortunately, SO many gateways botch source
- * routing, the thing is almost worthless. Maybe one day...
- *
- * -- Van Jacobson (van@helios.ee.lbl.gov)
- * Tue Dec 20 03:50:13 PST 1988
- */
- #include <sys/param.h>;
- #include <sys/time.h>;
- #include <sys/socket.h>;
- #include <sys/file.h>;
- #include <sys/ioctl.h>;
- #include <netinet/in_systm.h>;
- #include <netinet/in.h>;
- #include <netinet/ip.h>;
- #include <netinet/ip_icmp.h>;
- #include <netinet/udp.h>;
- #include <arpa/inet.h>;
- #include <netdb.h>;
- #include <stdio.h>;
- #include <errno.h>;
- #include <stdlib.h>;
- #include <string.h>;
- #include <unistd.h>;
- #define MAXPACKET 65535 /* max ip packet size */
- #ifndef MAXHOSTNAMELEN
- #define MAXHOSTNAMELEN 64
- #endif
- #ifndef FD_SET
- #define NFDBITS (8*sizeof(fd_set))
- #define FD_SETSIZE NFDBITS
- #define FD_SET(n, p) ((p)->;fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
- #define FD_CLR(n, p) ((p)->;fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
- #define FD_ISSET(n, p) ((p)->;fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
- #define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
- #endif
- #define Fprintf (void)fprintf
- #define Sprintf (void)sprintf
- #define Printf (void)printf
- /*
- * format of a (udp) probe packet.
- */
- struct opacket {
- struct ip ip;
- struct udphdr udp;
- u_char seq; /* sequence number of this packet */
- u_char ttl; /* ttl packet left with */
- struct timeval tv; /* time packet left */
- };
- u_char packet[512]; /* last inbound (icmp) packet */
- struct opacket *outpacket; /* last output (udp) packet */
- int wait_for_reply __P((int, struct sockaddr_in *));
- void send_probe __P((int, int));
- double deltaT __P((struct timeval *, struct timeval *));
- int packet_ok __P((u_char *, int, struct sockaddr_in *, int));
- void print __P((u_char *, int, struct sockaddr_in *));
- void tvsub __P((struct timeval *, struct timeval *));
- char *inetname __P((struct in_addr));
- void usage __P(());
- int s; /* receive (icmp) socket file descriptor */
- int sndsock; /* send (udp) socket file descriptor */
- struct timezone tz; /* leftover */
- struct sockaddr whereto; /* Who to try to reach */
- int datalen; /* How much data */
- int datalen;
- char *source = 0;
- char *hostname;
- int nprobes = 3;
- int max_ttl = 30;
- u_short ident;
- u_short port = 32768+666; /* start udp dest port # for probe packets */
- int options; /* socket options */
- int verbose;
- int waittime = 5; /* time to wait for response (in seconds) */
- int nflag; /* print addresses numerically */
- int
- main(argc, argv)
- int argc;
- char *argv[];
- {
- extern char *optarg;
- extern int optind;
- struct hostent *hp;
- struct protoent *pe;
- struct sockaddr_in from, *to;
- int ch, i, on, probe, seq, tos, ttl;
- on = 1;
- seq = tos = 0;
- to = (struct sockaddr_in *)&
- while ((ch = getopt(argc, argv, "dm:np:q:rs:t:w:v")) != EOF)
- switch(ch) {
- case 'd':
- options |= SO_DEBUG;
- break;
- case 'm':
- max_ttl = atoi(optarg);
- if (max_ttl <= 1) {
- Fprintf(stderr,
- "traceroute: max ttl must be >;1.\n");
- exit(1);
- }
- break;
- case 'n':
- nflag++;
- break;
- case 'p':
- port = atoi(optarg);
- if (port < 1) {
- Fprintf(stderr,
- "traceroute: port must be >;0.\n");
- exit(1);
- }
- break;
- case 'q':
- nprobes = atoi(optarg);
- if (nprobes < 1) {
- Fprintf(stderr,
- "traceroute: nprobes must be >;0.\n");
- exit(1);
- }
- break;
- case 'r':
- options |= SO_DONTROUTE;
- break;
- case 's':
- /*
- * set the ip source address of the outbound
- * probe (e.g., on a multi-homed host).
- */
- source = optarg;
- break;
- case 't':
- tos = atoi(optarg);
- if (tos < 0 || tos >; 255) {
- Fprintf(stderr,
- "traceroute: tos must be 0 to 255.\n");
- exit(1);
- }
- break;
- case 'v':
- verbose++;
- break;
- case 'w':
- waittime = atoi(optarg);
- if (waittime <= 1) {
- Fprintf(stderr,
- "traceroute: wait must be >;1 sec.\n");
- exit(1);
- }
- break;
- default:
- usage();
- }
- argc -= optind;
- argv += optind;
- if (argc < 1)
- usage();
- setlinebuf (stdout);
- (void) bzero((char *)&whereto, sizeof(struct sockaddr));
- to->;sin_family = AF_INET;
- to->;sin_addr.s_addr = inet_addr(*argv);
- if (to->;sin_addr.s_addr != -1)
- hostname = *argv;
- else {
- hp = gethostbyname(*argv);
- if (hp) {
- to->;sin_family = hp->;h_addrtype;
- bcopy(hp->;h_addr, (caddr_t)&to->;sin_addr, hp->;h_length);
- hostname = hp->;h_name;
- } else {
- (void)fprintf(stderr,
- "traceroute: unknown host %s\n", *argv);
- exit(1);
- }
- }
- if (*++argv)
- datalen = atoi(*argv);
- if (datalen < 0 || datalen >;= MAXPACKET - sizeof(struct opacket)) {
- Fprintf(stderr,
- "traceroute: packet size must be 0 <= s < %ld.\n",
- MAXPACKET - sizeof(struct opacket));
- exit(1);
- }
- datalen += sizeof(struct opacket);
- outpacket = (struct opacket *)malloc((unsigned)datalen);
- if (! outpacket) {
- perror("traceroute: malloc");
- exit(1);
- }
- (void) bzero((char *)outpacket, datalen);
- outpacket->;ip.ip_dst = to->;sin_addr;
- outpacket->;ip.ip_tos = tos;
- outpacket->;ip.ip_v = IPVERSION;
- outpacket->;ip.ip_id = 0;
- ident = (getpid() & 0xffff) | 0x8000;
- if ((pe = getprotobyname("icmp")) == NULL) {
- Fprintf(stderr, "icmp: unknown protocol\n");
- exit(10);
- }
- if ((s = socket(AF_INET, SOCK_RAW, pe->;p_proto)) < 0) {
- perror("traceroute: icmp socket");
- exit(5);
- }
- if (options & SO_DEBUG)
- (void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
- (char *)&on, sizeof(on));
- if (options & SO_DONTROUTE)
- (void) setsockopt(s, SOL_SOCKET, SO_DONTROUTE,
- (char *)&on, sizeof(on));
- if ((sndsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
- perror("traceroute: raw socket");
- exit(5);
- }
- #ifdef SO_SNDBUF
- if (setsockopt(sndsock, SOL_SOCKET, SO_SNDBUF, (char *)&datalen,
- sizeof(datalen)) < 0) {
- perror("traceroute: SO_SNDBUF");
- exit(6);
- }
- #endif
- #ifdef IP_HDRINCL
- if (setsockopt(sndsock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
- sizeof(on)) < 0) {
- perror("traceroute: IP_HDRINCL");
- exit(6);
- }
- #endif
- if (options & SO_DEBUG)
- (void) setsockopt(sndsock, SOL_SOCKET, SO_DEBUG,
- (char *)&on, sizeof(on));
- if (options & SO_DONTROUTE)
- (void) setsockopt(sndsock, SOL_SOCKET, SO_DONTROUTE,
- (char *)&on, sizeof(on));
- if (source) {
- (void) bzero((char *)&from, sizeof(struct sockaddr));
- from.sin_family = AF_INET;
- from.sin_addr.s_addr = inet_addr(source);
- if (from.sin_addr.s_addr == -1) {
- Printf("traceroute: unknown host %s\n", source);
- exit(1);
- }
- outpacket->;ip.ip_src = from.sin_addr;
- #ifndef IP_HDRINCL
- if (bind(sndsock, (struct sockaddr *)&from, sizeof(from)) < 0) {
- perror ("traceroute: bind:");
- exit (1);
- }
- #endif
- }
- Fprintf(stderr, "traceroute to %s (%s)", hostname,
- inet_ntoa(to->;sin_addr));
- if (source)
- Fprintf(stderr, " from %s", source);
- Fprintf(stderr, ", %d hops max, %d byte packets\n", max_ttl, datalen);
- (void) fflush(stderr);
- for (ttl = 1; ttl <= max_ttl; ++ttl) {
- u_long lastaddr = 0;
- int got_there = 0;
- int unreachable = 0;
- Printf("%2d ", ttl);
- for (probe = 0; probe < nprobes; ++probe) {
- int cc;
- struct timeval t1, t2;
- struct timezone tz;
- struct ip *ip;
- (void) gettimeofday(&t1, &tz);
- send_probe(++seq, ttl);
- while (cc = wait_for_reply(s, &from)) {
- (void) gettimeofday(&t2, &tz);
- if ((i = packet_ok(packet, cc, &from, seq))) {
- if (from.sin_addr.s_addr != lastaddr) {
- print(packet, cc, &from);
- lastaddr = from.sin_addr.s_addr;
- }
- Printf(" %g ms", deltaT(&t1, &t2));
- switch(i - 1) {
- case ICMP_UNREACH_PORT:
- #ifndef ARCHAIC
- ip = (struct ip *)packet;
- if (ip->;ip_ttl <= 1)
- Printf(" !");
- #endif
- ++got_there;
- break;
- case ICMP_UNREACH_NET:
- ++unreachable;
- Printf(" !N");
- break;
- case ICMP_UNREACH_HOST:
- ++unreachable;
- Printf(" !H");
- break;
- case ICMP_UNREACH_PROTOCOL:
- ++got_there;
- Printf(" !P");
- break;
- case ICMP_UNREACH_NEEDFRAG:
- ++unreachable;
- Printf(" !F");
- break;
- case ICMP_UNREACH_SRCFAIL:
- ++unreachable;
- Printf(" !S");
- break;
- }
- break;
- }
- }
- if (cc == 0)
- Printf(" *");
- (void) fflush(stdout);
- }
- putchar('\n');
- if (got_there || unreachable >;= nprobes-1)
- exit(0);
- }
- }
- int
- wait_for_reply(sock, from)
- int sock;
- struct sockaddr_in *from;
- {
- fd_set fds;
- struct timeval wait;
- int cc = 0;
- int fromlen = sizeof (*from);
- FD_ZERO(&fds);
- FD_SET(sock, &fds);
- wait.tv_sec = waittime; wait.tv_usec = 0;
- if (select(sock+1, &fds, (fd_set *)0, (fd_set *)0, &wait) >; 0)
- cc=recvfrom(s, (char *)packet, sizeof(packet), 0,
- (struct sockaddr *)from, &fromlen);
- return(cc);
- }
- void
- send_probe(seq, ttl)
- int seq, ttl;
- {
- struct opacket *op = outpacket;
- struct ip *ip = &op->;ip;
- struct udphdr *up = &op->;udp;
- int i;
- ip->;ip_off = 0;
- ip->;ip_hl = sizeof(*ip) >;>; 2;
- ip->;ip_p = IPPROTO_UDP;
- ip->;ip_len = datalen;
- ip->;ip_ttl = ttl;
- ip->;ip_v = IPVERSION;
- ip->;ip_id = htons(ident+seq);
- up->;source= htons(ident);
- up->;dest = htons(port+seq);
- up->;len = htons((u_short)(datalen - sizeof(struct ip)));
- up->;check = 0;
- op->;seq = seq;
- op->;ttl = ttl;
- (void) gettimeofday(&op->;tv, &tz);
- i = sendto(sndsock, (char *)outpacket, datalen, 0, &whereto,
- sizeof(struct sockaddr));
- if (i < 0 || i != datalen) {
- if (i<0)
- perror("sendto");
- Printf("traceroute: wrote %s %d chars, ret=%d\n", hostname,
- datalen, i);
- (void) fflush(stdout);
- }
- }
- double
- deltaT(t1p, t2p)
- struct timeval *t1p, *t2p;
- {
- register double dt;
- dt = (double)(t2p->;tv_sec - t1p->;tv_sec) * 1000.0 +
- (double)(t2p->;tv_usec - t1p->;tv_usec) / 1000.0;
- return (dt);
- }
- /*
- * Convert an ICMP "type" field to a printable string.
- */
- char *
- pr_type(t)
- u_char t;
- {
- static char *ttab[] = {
- "Echo Reply", "ICMP 1", "ICMP 2", "Dest Unreachable",
- "Source Quench", "Redirect", "ICMP 6", "ICMP 7",
- "Echo", "ICMP 9", "ICMP 10", "Time Exceeded",
- "Param Problem", "Timestamp", "Timestamp Reply", "Info Request",
- "Info Reply"
- };
- if(t >; 16)
- return("OUT-OF-RANGE");
- return(ttab[t]);
- }
- /*验证收到的数据包
- 包的格式是
- |------------------------- cc ----------------------------------------|
- |------ hlen----------- |
- |-------------- ICMP len--------------------------|
- 20 bytes 0-40 bytes 8 bytes 20 bytes 0-40 bytes 8 bytes
- ___________________________________________________________________________
- | IP header | IP option | ICMP header | IP header | IP option | UDP header |
- |___________|___________|_____________|___________|___________|____________|
-
- |--------ICMP data ------------------|
- */
- int
- packet_ok(buf, cc, from, seq)
- u_char *buf;
- int cc;
- struct sockaddr_in *from;
- int seq;
- {
- register struct icmp *icp;
- u_char type, code;
- int hlen;
- #ifndef ARCHAIC
- struct ip *ip;
- ip = (struct ip *) buf;
- hlen = ip->;ip_hl << 2; /*header length,include option*/
- if (cc < hlen + ICMP_MINLEN) {
- if (verbose)
- Printf("packet too short (%d bytes) from %s\n", cc,
- inet_ntoa(from->;sin_addr));
- return (0);
- }
- cc -= hlen;
- icp = (struct icmp *)(buf + hlen);
- #else
- icp = (struct icmp *)buf;
- #endif
- type = icp->;icmp_type; code = icp->;icmp_code;
- if ((type == ICMP_TIMXCEED && code == ICMP_TIMXCEED_INTRANS) ||
- type == ICMP_UNREACH) {
- struct ip *hip;
- struct udphdr *up;
- hip = &icp->;icmp_ip;
- hlen = hip->;ip_hl << 2;
- up = (struct udphdr *)((u_char *)hip + hlen);
- if (hlen + 12 <= cc && hip->;ip_p == IPPROTO_UDP &&
- up->;source == htons(ident) &&
- up->;dest == htons(port+seq))
- return (type == ICMP_TIMXCEED? -1 : code+1);
- }
- #ifndef ARCHAIC
- if (verbose) {
- int i;
- u_long *lp = (u_long *)&icp->;icmp_ip;
- Printf("\n%d bytes from %s to %s", cc,
- inet_ntoa(from->;sin_addr), inet_ntoa(ip->;ip_dst));
- Printf(": icmp type %d (%s) code %d\n", type, pr_type(type),
- icp->;icmp_code);
- for (i = 4; i < cc ; i += sizeof(long))
- Printf("%2d: x%8.8lx\n", i, *lp++);
- }
- #endif
- return(0);
- }
- void
- print(buf, cc, from)
- u_char *buf;
- int cc;
- struct sockaddr_in *from;
- {
- struct ip *ip;
- int hlen;
- ip = (struct ip *) buf;
- hlen = ip->;ip_hl << 2;
- cc -= hlen;
- if (nflag)
- Printf(" %s", inet_ntoa(from->;sin_addr));
- else
- Printf(" %s (%s)", inetname(from->;sin_addr),
- inet_ntoa(from->;sin_addr));
- if (verbose)
- Printf (" %d bytes to %s", cc, inet_ntoa (ip->;ip_dst));
- }
- #ifdef notyet
- /*
- * Checksum routine for Internet Protocol family headers (C Version)
- */
- u_short
- in_cksum(addr, len)
- u_short *addr;
- int len;
- {
- register int nleft = len;
- register u_short *w = addr;
- register u_short answer;
- register int sum = 0;
- /*
- * Our algorithm is simple, using a 32 bit accumulator (sum),
- * we add sequential 16 bit words to it, and at the end, fold
- * back all the carry bits from the top 16 bits into the lower
- * 16 bits.
- */
- while (nleft >; 1) {
- sum += *w++;
- nleft -= 2;
- }
- /* mop up an odd byte, if necessary */
- if (nleft == 1)
- sum += *(u_char *)w;
- /*
- * add back carry outs from top 16 bits to low 16 bits
- */
- sum = (sum >;>; 16) + (sum & 0xffff); /* add hi 16 to low 16 */
- sum += (sum >;>; 16); /* add carry */
- answer = ~sum; /* truncate to 16 bits */
- return (answer);
- }
- #endif
- /*
- * Subtract 2 timeval structs: out = out - in.
- * Out is assumed to be >;= in.
- */
- void
- tvsub(out, in)
- register struct timeval *out, *in;
- {
- if ((out->;tv_usec -= in->;tv_usec) < 0) {
- out->;tv_sec--;
- out->;tv_usec += 1000000;
- }
- out->;tv_sec -= in->;tv_sec;
- }
- /*
- * Construct an Internet address representation.
- * If the nflag has been supplied, give
- * numeric value, otherwise try for symbolic name.
- */
- char *
- inetname(in)
- struct in_addr in;
- {
- register char *cp;
- static char line[50];
- struct hostent *hp;
- static char domain[MAXHOSTNAMELEN + 1];
- static int first = 1;
- if (first && !nflag) {
- first = 0;
- if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
- (cp = index(domain, '.')))
- (void) strcpy(domain, cp + 1);
- else
- domain[0] = 0;
- }
- cp = 0;
- if (!nflag && in.s_addr != INADDR_ANY) {
- hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET);
- if (hp) {
- if ((cp = index(hp->;h_name, '.')) &&
- !strcmp(cp + 1, domain))
- *cp = 0;
- cp = hp->;h_name;
- }
- }
- if (cp)
- (void) strcpy(line, cp);
- else {
- in.s_addr = ntohl(in.s_addr);
- #define C(x) ((x) & 0xff)
- Sprintf(line, "%lu.%lu.%lu.%lu", C(in.s_addr >;>; 24),
- C(in.s_addr >;>; 16), C(in.s_addr >;>; 8), C(in.s_addr));
- }
- return (line);
- }
- void
- usage()
- {
- (void)fprintf(stderr,
- "usage: traceroute [-dnrv] [-m max_ttl] [-p port#] [-q nqueries]\n\t\
- [-s src_addr] [-t tos] [-w wait] host [data size]\n");
- exit(1);
- }
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免费注册
发表于 2005-06-27 13:20
, 30 hops max, 38 byte packets 