mtrace.c

mtrace源码

		if (r->tr_outaddr == 0)
		    r->tr_outaddr = recvaddr.sin_addr.s_addr;

		/*
		 * A match, we'll keep this one.
		 */
		if (len > code) {
		    fprintf(stderr,
			    "Num hops received (%d) exceeds request (%d)\n",
			    len, code);
		}
		rquery->tr_raddr = query->tr_raddr;	/* Insure these are */
		TR_SETTTL(rquery->tr_rttlqid, TR_GETTTL(query->tr_rttlqid));
							/* as we sent them */
		break;

	      default:
		continue;
	    }

	    /*
	     * We're pretty sure we want to use this packet now,
	     * but if the caller gave a callback function, it might
	     * want to handle it instead.  Give the callback a chance,
	     * unless the select timed out (in which case the only way
	     * to get here is because the callback returned a packet).
	     */
	    if (callback && (count != 0) && ((callback)(0, recv_buf, recvlen, igmp, igmpdatalen, (struct sockaddr*)&recvaddr, &socklen, &tr)) == 0) {
		/*
		 * The callback function didn't like this packet.
		 * Go try receiving another one.
		 */
		continue;
	    }

	    /*
	     * Most of the sanity checking done at this point.
	     * Return this packet we have been waiting for.
	     */
	    if (save) {
		save->qtime = ((tq.tv_sec + JAN_1970) << 16) +
			      (tq.tv_usec << 10) / 15625;
		save->rtime = ((tr.tv_sec + JAN_1970) << 16) +
			      (tr.tv_usec << 10) / 15625;
		save->len = len;
		bcopy((char *)igmp, (char *)&save->igmp, ipdatalen);
	    }
	    return (recvlen);
	}
    }
    return (0);
}

/*
 * Most of this code is duplicated elsewhere.  I'm not sure if
 * the duplication is absolutely required or not.
 *
 * Ideally, this would keep track of ongoing statistics
 * collection and print out statistics.  (& keep track
 * of h-b-h traces and only print the longest)  For now,
 * it just snoops on what traces it can.
 */
void
passive_mode()
{
    struct timeval tr;
    struct ip *ip;
    struct igmp *igmp;
    struct tr_resp *r;
    struct sockaddr_in recvaddr;
    struct tm *now;
    char timebuf[32];
    int socklen;
    int ipdatalen, iphdrlen, igmpdatalen;
    int len, recvlen;
    int qid;
    u_int32 smask;
    struct mtrace *remembered = NULL, *m, *n, **nn;
    int pc = 0;

    if (raddr) {
	if (IN_MULTICAST(ntohl(raddr))) k_join(raddr, lcl_addr);
    } else k_join(htonl(0xE0000120), lcl_addr);

    while (1) {
	fflush(stdout);		/* make sure previous trace is flushed */

	socklen = sizeof(recvaddr);
	recvlen = recvfrom(igmp_socket, recv_buf, RECV_BUF_SIZE,
			   0, (struct sockaddr *)&recvaddr, &socklen);
	gettimeofday(&tr,0);

	if (recvlen <= 0) {
	    if (recvlen && errno != EINTR) perror("recvfrom");
	    continue;
	}

	if (recvlen < sizeof(struct ip)) {
	    fprintf(stderr,
		    "packet too short (%u bytes) for IP header", recvlen);
	    continue;
	}
	ip = (struct ip *) recv_buf;
	if (ip->ip_p == 0)	/* ignore cache creation requests */
	    continue;

	iphdrlen = ip->ip_hl << 2;
#ifdef RAW_INPUT_IS_RAW
	ipdatalen = ntohs(ip->ip_len);
#else
	ipdatalen = ip->ip_len;
#endif
	if (iphdrlen + ipdatalen != recvlen) {
	    fprintf(stderr,
		    "packet shorter (%u bytes) than hdr+data len (%u+%u)\n",
		    recvlen, iphdrlen, ipdatalen);
	    continue;
	}

	igmp = (struct igmp *) (recv_buf + iphdrlen);
	igmpdatalen = ipdatalen - IGMP_MINLEN;
	if (igmpdatalen < 0) {
	    fprintf(stderr,
		    "IP data field too short (%u bytes) for IGMP from %s\n",
		    ipdatalen, inet_fmt(ip->ip_src.s_addr, s1));
	    continue;
	}

	switch (igmp->igmp_type) {

	  case IGMP_MTRACE:	    /* For backward compatibility with 3.3 */
	  case IGMP_MTRACE_RESP:
	    if (igmpdatalen < QLEN) continue;
	    if ((igmpdatalen - QLEN)%RLEN) {
		printf("packet with incorrect datalen\n");
		continue;
	    }

	    len = (igmpdatalen - QLEN)/RLEN;

	    break;

	  default:
	    continue;
	}

	base.qtime = ((tr.tv_sec + JAN_1970) << 16) +
		      (tr.tv_usec << 10) / 15625;
	base.rtime = ((tr.tv_sec + JAN_1970) << 16) +
		      (tr.tv_usec << 10) / 15625;
	base.len = len;
	bcopy((char *)igmp, (char *)&base.igmp, ipdatalen);
	/*
	 * If the user specified which traces to monitor,
	 * only accept traces that correspond to the
	 * request
	 */
	if ((qsrc != 0 && qsrc != base.qhdr.tr_src) ||
	    (qdst != 0 && qdst != base.qhdr.tr_dst) ||
	    (qgrp != 0 && qgrp != igmp->igmp_group.s_addr))
	    continue;

	/* XXX This should be a hash table */
	/* XXX garbage-collection should be more efficient */
	for (nn = &remembered, n = *nn, m = 0; n; n = *nn) {
	    if ((n->base.qhdr.tr_src == base.qhdr.tr_src) &&
		(n->base.qhdr.tr_dst == base.qhdr.tr_dst) &&
		(n->base.igmp.igmp_group.s_addr == igmp->igmp_group.s_addr)) {
		m = n;
		m->last = tr;
	    }
	    if (tr.tv_sec - n->last.tv_sec > 500) { /* XXX don't hardcode */
		*nn = n->next;
		free(n);
	    } else {
		nn = &n->next;
	    }
	}

	now = localtime(&tr.tv_sec);
	strftime(timebuf, sizeof(timebuf) - 1, "%b %e %k:%M:%S", now);
	printf("Mtrace %s at %s",
		len == 0 ? "query" :
			   igmp->igmp_type == IGMP_MTRACE_RESP ? "response" :
								 "in transit",
		timebuf);
	if (len == 0)
		printf(" by %s", inet_fmt(recvaddr.sin_addr.s_addr, s1));
	if (!IN_MULTICAST(base.qhdr.tr_raddr))
		printf(", resp to %s", (len == 0 && recvaddr.sin_addr.s_addr == base.qhdr.tr_raddr) ? "same" : inet_fmt(base.qhdr.tr_raddr, s1));
	else
		printf(", respttl %d", TR_GETTTL(base.qhdr.tr_rttlqid));
	printf(", qid %06x\n", qid = TR_GETQID(base.qhdr.tr_rttlqid));
	printf("packet from %s to %s\n",
		inet_fmt(ip->ip_src.s_addr, s1),
		inet_fmt(ip->ip_dst.s_addr, s2));

	printf("from %s to %s via group %s (mxhop=%d)\n",
		inet_fmt(base.qhdr.tr_dst, s1), inet_fmt(base.qhdr.tr_src, s2),
		inet_fmt(igmp->igmp_group.s_addr, s3), igmp->igmp_code);
	if (len == 0) {
	    printf("\n");
	    continue;
	}
	r = base.resps + base.len - 1;
	/*
	 * Some routers will return error messages without
	 * filling in their addresses.  We fill in the address
	 * for them.
	 */
	if (r->tr_outaddr == 0)
	    r->tr_outaddr = recvaddr.sin_addr.s_addr;

	/*
	 * If there was a previous trace, it see if this is a
	 * statistics candidate.
	 */
	if (m && base.len == m->base.len &&
		!(pc = path_changed(&m->base, &base))) {
	    /*
	     * Some mtrace responders send multiple copies of the same
	     * reply.  Skip this packet if it's got the same query-id
	     * as the last one.
	     */
	    if (m->lastqid == qid) {
		printf("Skipping duplicate reply\n");
		continue;
	    }

	    m->lastqid = qid;

	    ++m->nresp;

	    bcopy(&base, m->new, sizeof(base));

	    printf("Results after %d seconds:\n\n",
		   (int)((m->new->qtime - m->base.qtime) >> 16));
	    fixup_stats(&m->base, m->prev, m->new, m->bugs);
	    print_stats(&m->base, m->prev, m->new, m->bugs, m->names);
	    m->prev = m->new;
	    m->new = &m->incr[(m->nresp & 1)];

	    continue;
	}

	if (m == NULL) {
	    m = (struct mtrace *)malloc(sizeof(struct mtrace));
	    if (m == NULL) {
		fprintf(stderr, "Out of memory!\n");
		continue;
	    }
	    bzero(m, sizeof(struct mtrace));
	    m->next = remembered;
	    remembered = m;
	    bcopy(&tr, &m->last, sizeof(tr));
	}

	/* Either it's a hop-by-hop in progress, or the path changed. */
	if (pc) {
	    printf("[Path Changed...]\n");
	    bzero(m->bugs, sizeof(m->bugs));
	}
	bcopy(&base, &m->base, sizeof(base));
	m->prev = &m->base;
	m->new = &m->incr[0];
	m->nresp = 0;

	printf("  0  ");
	print_host(base.qhdr.tr_dst);
	printf("\n");
	print_trace(1, &base, m->names);
	VAL_TO_MASK(smask, r->tr_smask);
	if ((r->tr_inaddr & smask) == (base.qhdr.tr_src & smask)) {
	    printf("%3d  ", -(base.len+1));
	    print_host(base.qhdr.tr_src);
	    printf("\n");
	} else if (r->tr_rmtaddr != 0) {
	    printf("%3d  ", -(base.len+1));
	    print_host(r->tr_rmtaddr);
	    printf(" %s\n", r->tr_rflags == TR_OLD_ROUTER ?
				   "doesn't support mtrace"
				 : "is the next hop");
	}
	printf("\n");
    }
}

char *
print_host(addr)
    u_int32 addr;
{
    return print_host2(addr, 0);
}

/*
 * On some routers, one interface has a name and the other doesn't.
 * We always print the address of the outgoing interface, but can
 * sometimes get the name from the incoming interface.  This might be
 * confusing but should be slightly more helpful than just a "?".
 */
char *
print_host2(addr1, addr2)
    u_int32 addr1, addr2;
{
    char *name;

    if (numeric) {
	printf("%s", inet_fmt(addr1, s1));
	return ("");
    }
    name = inet_name(addr1);
    if (*name == '?' && *(name + 1) == '\0' && addr2 != 0)
	name = inet_name(addr2);
    printf("%s (%s)", name, inet_fmt(addr1, s1));
    return (name);
}

/*
 * Print responses as received (reverse path from dst to src)
 */
void
print_trace(idx, buf, names)
    int idx;
    struct resp_buf *buf;
    char **names;
{
    struct tr_resp *r;
    char *name;
    int i;
    int hop;
    char *ms;

    i = abs(idx);
    r = buf->resps + i - 1;

    for (; i <= buf->len; ++i, ++r) {
	if (idx > 0) printf("%3d  ", -i);
	name = print_host2(r->tr_outaddr, r->tr_inaddr);
	if (r->tr_rflags != TR_NO_RTE)
	    printf("  %s  thresh^ %d", proto_type(r->tr_rproto), r->tr_fttl);
	if (verbose) {
	    hop = t_diff(ntohl(r->tr_qarr), buf->qtime);
	    ms = scale(&hop);
	    printf("  %d%s", hop, ms);
	}
	printf("  %s", flag_type(r->tr_rflags));
	if (i > 1 && r->tr_outaddr != (r-1)->tr_rmtaddr) {
	    printf(" !RPF!");
	    print_host((r-1)->tr_rmtaddr);
	}
	if (r->tr_rflags != TR_NO_RTE) {
	    if (r->tr_smask <= 1)    /* MASK_TO_VAL() returns 1 for default */
		printf(" [default]");
	    else if (verbose) {
		u_int32 smask;

		VAL_TO_MASK(smask, r->tr_smask);
		printf(" [%s]", inet_fmts(buf->qhdr.tr_src & smask,
							smask, s1));
	    }
	}
	printf("\n");
	if (names[i-1])
	    free(names[i-1]);
	names[i-1]=malloc(strlen(name) + 1);
	strcpy(names[i-1], name);
    }
}

/*
 * See what kind of router is the next hop
 */
int
what_kind(buf, why)
    struct resp_buf *buf;
    char *why;
{
    u_int32 smask;
    int retval;
    int hops = buf->len;
    struct tr_resp *r = buf->resps + hops - 1;
    u_int32 next = r->tr_rmtaddr;

    retval = send_recv(next, IGMP_DVMRP, DVMRP_ASK_NEIGHBORS2, 1, &incr[0], NULL);
    print_host(next);
    if (retval) {
	u_int32 version = ntohl(incr[0].igmp.igmp_group.s_addr);
	u_int32 *p = (u_int32 *)incr[0].ndata;
	u_int32 *ep = p + (incr[0].len >> 2);
	char *type = "version ";

	retval = 0;
	switch (version & 0xFF) {
	  case 1:
	    type = "proteon/mrouted ";
	    retval = 1;
	    break;

	  case 10:
	  case 11:
	    type = "cisco ";
	}
	printf(" [%s%d.%d] %s\n",
	       type, version & 0xFF, (version >> 8) & 0xFF,
	       why);
	VAL_TO_MASK(smask, r->tr_smask);
	while (p < ep) {
	    u_int32 laddr = *p++;
	    int flags = (ntohl(*p) & 0xFF00) >> 8;
	    int n = ntohl(*p++) & 0xFF;
	    if (!(flags & (DVMRP_NF_DOWN | DVMRP_NF_DISABLED)) &&
		 (laddr & smask) == (qsrc & smask)) {
		printf("%3d  ", -(hops+2));
		print_host(qsrc);
		printf("\n");
		return 1;
	    }
	    p += n;
	}
	return retval;
    }
    printf(" %s\n", why);
    return 0;
}


char *
scale(hop)
    int *hop;
{
    if (*hop > -1000 && *hop < 10000) return (" ms");
    *hop /= 1000;
    if (*hop > -1000 && *hop < 10000) return (" s ");
    return ("s ");
}

/*
 * Calculate and print one line of packet loss and packet rate statistics.
 * Checks for count of all ones from mrouted 2.3 that doesn't have counters.
 */
#define NEITHER 0
#define INS     1
#define OUTS    2
#define BOTH    3
void
stat_line(r, s, have_next, rst)
    struct tr_resp *r, *s;
    int have_next;
    int *rst;
{
    int timediff = (ntohl(s->tr_qarr) - ntohl(r->tr_qarr)) >> 16;
    int v_lost, v_pct;
    int g_lost, g_pct;
    int v_out = ntohl(s->tr_vifout) - ntohl(r->tr_vifout);
    int g_out = ntohl(s->tr_pktcnt) - ntohl(r->tr_pktcnt);
    int v_pps, g_pps;
    char v_str[8], g_str[8];
    int vhave = NEITHER;
    int ghave = NEITHER;
    int gmissing = NEITHER;
    char whochar;
    int badtime = 0;

    if (timediff == 0) {
	badtime = 1;
	/* Might be 32 bits of int seconds instead of 16int+16frac */
	timediff = ntohl(s->tr_qarr) - ntohl(r->tr_qarr);
	if (timediff == 0 || abs(timediff - statint) > statint)
	    timediff = 1;
    }
    v_pps = v_out / timediff;
    g_pps = g_out / timediff;