traceroute.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

/*-
 * 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.
 *
 * Special for busybox ported by Vladimir Oleynik <[e-mail]> 2001
 * 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. 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.
 */

/*
 * traceroute host  - trace the route ip packets follow going to "host".
 * 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.)
 *
 * 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 ([e-mail])
 *     Tue Dec 20 03:50:13 PST 1988
 */

#undef CONFIG_FEATURE_TRACEROUTE_VERBOSE
//#define CONFIG_FEATURE_TRACEROUTE_VERBOSE
#undef CONFIG_FEATURE_TRACEROUTE_SO_DEBUG   /* not in documentation man */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include "inet_common.h"
#include <netdb.h>
#include <endian.h>
#include <netinet/udp.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>

 
 /* It turns out that libc5 doesn't have proper icmp support
 * built into it header files, so we have to supplement it */
#if __GNU_LIBRARY__ < 5
static const int ICMP_MINLEN = 8;				/* abs minimum */

struct icmp_ra_addr
{
  u_int32_t ira_addr;
  u_int32_t ira_preference;
};


struct icmp
{
  u_int8_t  icmp_type;	/* type of message, see below */
  u_int8_t  icmp_code;	/* type sub code */
  u_int16_t icmp_cksum;	/* ones complement checksum of struct */
  union
  {
    u_char ih_pptr;		/* ICMP_PARAMPROB */
    struct in_addr ih_gwaddr;	/* gateway address */
    struct ih_idseq		/* echo datagram */
    {
      u_int16_t icd_id;
      u_int16_t icd_seq;
    } ih_idseq;
    u_int32_t ih_void;

    /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
    struct ih_pmtu
    {
      u_int16_t ipm_void;
      u_int16_t ipm_nextmtu;
    } ih_pmtu;

    struct ih_rtradv
    {
      u_int8_t irt_num_addrs;
      u_int8_t irt_wpa;
      u_int16_t irt_lifetime;
    } ih_rtradv;
  } icmp_hun;
#define	icmp_pptr	icmp_hun.ih_pptr
#define	icmp_gwaddr	icmp_hun.ih_gwaddr
#define	icmp_id		icmp_hun.ih_idseq.icd_id
#define	icmp_seq	icmp_hun.ih_idseq.icd_seq
#define	icmp_void	icmp_hun.ih_void
#define	icmp_pmvoid	icmp_hun.ih_pmtu.ipm_void
#define	icmp_nextmtu	icmp_hun.ih_pmtu.ipm_nextmtu
#define	icmp_num_addrs	icmp_hun.ih_rtradv.irt_num_addrs
#define	icmp_wpa	icmp_hun.ih_rtradv.irt_wpa
#define	icmp_lifetime	icmp_hun.ih_rtradv.irt_lifetime
  union
  {
    struct
    {
      u_int32_t its_otime;
      u_int32_t its_rtime;
      u_int32_t its_ttime;
    } id_ts;
    struct
    {
      struct ip idi_ip;
      /* options and then 64 bits of data */
    } id_ip;
    struct icmp_ra_addr id_radv;
    u_int32_t   id_mask;
    u_int8_t    id_data[1];
  } icmp_dun;
#define	icmp_otime	icmp_dun.id_ts.its_otime
#define	icmp_rtime	icmp_dun.id_ts.its_rtime
#define	icmp_ttime	icmp_dun.id_ts.its_ttime
#define	icmp_ip		icmp_dun.id_ip.idi_ip
#define	icmp_radv	icmp_dun.id_radv
#define	icmp_mask	icmp_dun.id_mask
#define	icmp_data	icmp_dun.id_data
};

#define	ICMP_MINLEN	8				/* abs minimum */
#define	ICMP_UNREACH		3		/* dest unreachable, codes: */
#define	ICMP_TIMXCEED		11		/* time exceeded, code: */
#define	ICMP_TIMXCEED_INTRANS	0		/* ttl==0 in transit */
#define	ICMP_UNREACH_NET	        0	/* bad net */
#define	ICMP_UNREACH_HOST	        1	/* bad host */
#define	ICMP_UNREACH_PROTOCOL	        2	/* bad protocol */
#define	ICMP_UNREACH_PORT	        3	/* bad port */
#define	ICMP_UNREACH_NEEDFRAG	        4	/* IP_DF caused drop */
#define	ICMP_UNREACH_SRCFAIL	        5	/* src route failed */
#endif


#define MAXPACKET       65535   /* max ip packet size */
#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN  64
#endif

/*
 * 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 */
};

/*
 * Definitions for internet protocol version 4.
 * Per RFC 791, September 1981.
 */
#define IPVERSION       4


#include "busybox.h"

static u_char  packet[512];            /* last inbound (icmp) packet */
static struct opacket  *outpacket;     /* last output (udp) packet */

static int s;                          /* receive (icmp) socket file descriptor */
static int sndsock;                    /* send (udp) socket file descriptor */

static struct sockaddr whereto;        /* Who to try to reach */
static int datalen;                    /* How much data */

static char *hostname;

static int max_ttl = 30;
static u_short ident;
static u_short port = 32768+666;       /* start udp dest port # for probe packets */

#ifdef CONFIG_FEATURE_TRACEROUTE_VERBOSE
static int verbose;
#endif
static int waittime = 5;               /* time to wait for response (in seconds) */
static int nflag;                      /* print addresses numerically */

/*
 * Construct an Internet address representation.
 * If the nflag has been supplied, give
 * numeric value, otherwise try for symbolic name.
 */
static inline void
inetname(struct sockaddr_in *from)
{
	char *cp;
	static char domain[MAXHOSTNAMELEN + 1];
	char name[MAXHOSTNAMELEN + 1];
	static int first = 1;
	const char *ina;

	if (first && !nflag) {
		first = 0;
		if (getdomainname(domain, MAXHOSTNAMELEN) != 0)
			domain[0] = 0;
	}
	cp = 0;
	if (!nflag && from->sin_addr.s_addr != INADDR_ANY) {
		if(INET_rresolve(name, sizeof(name), from, 0x4000, 0xffffffff) >= 0) {
			if ((cp = strchr(name, '.')) &&
			    !strcmp(cp + 1, domain))
				*cp = 0;
			cp = (char *)name;
		}
	}
	ina = inet_ntoa(from->sin_addr);
	if (nflag)
		printf(" %s", ina);
	else
		printf(" %s (%s)", (cp ? cp : ina), ina);
}

static inline void
print(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;

	inetname(from);
#ifdef CONFIG_FEATURE_TRACEROUTE_VERBOSE
	if (verbose)
		printf (" %d bytes to %s", cc, inet_ntoa (ip->ip_dst));
#endif
}

static inline double
deltaT(struct timeval *t1p, struct timeval *t2p)
{
	double dt;

	dt = (double)(t2p->tv_sec - t1p->tv_sec) * 1000.0 +
	     (double)(t2p->tv_usec - t1p->tv_usec) / 1000.0;
	return (dt);
}

static inline int
wait_for_reply(int sock, struct sockaddr_in *from, int reset_timer)
{
	fd_set fds;
	static struct timeval wait;
	int cc = 0;
	int fromlen = sizeof (*from);

	FD_ZERO(&fds);
	FD_SET(sock, &fds);
	if (reset_timer) {
		/*
		 * traceroute could hang if someone else has a ping
		 * running and our ICMP reply gets dropped but we don't
		 * realize it because we keep waking up to handle those
		 * other ICMP packets that keep coming in.  To fix this,
		 * "reset_timer" will only be true if the last packet that
		 * came in was for us or if this is the first time we're
		 * waiting for a reply since sending out a probe.  Note
		 * that this takes advantage of the select() feature on
		 * Linux where the remaining timeout is written to the
		 * struct timeval area.
		 */
		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);
}

#ifdef CONFIG_FEATURE_TRACEROUTE_VERBOSE
/*
 * Convert an ICMP "type" field to a printable string.
 */
static inline const char *
pr_type(u_char t)
{
	static const char * const ttab[] = {
	"Echo Reply",   "ICMP 1",       "ICMP 2",       "Dest Unreachable",
	"Source Quench", "Redirect",    "ICMP 6",       "ICMP 7",