mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-24 02:23:27 +08:00
259cb9ad02
Instead of checking that there are 8 bytes available at the beginning of an IGMP packet - which there might not be, e.g. with some DVMRP packets - do the checks as necessary before fetching values.
370 lines
8.1 KiB
C
370 lines
8.1 KiB
C
/*
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* Copyright (c) 1995, 1996
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static const char rcsid[] _U_ =
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"@(#) $Header: /tcpdump/master/tcpdump/print-dvmrp.c,v 1.27 2003-11-19 09:42:04 guy Exp $ (LBL)";
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#endif
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <tcpdump-stdinc.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "interface.h"
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#include "extract.h"
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#include "addrtoname.h"
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/*
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* DVMRP message types and flag values shamelessly stolen from
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* mrouted/dvmrp.h.
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*/
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#define DVMRP_PROBE 1 /* for finding neighbors */
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#define DVMRP_REPORT 2 /* for reporting some or all routes */
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#define DVMRP_ASK_NEIGHBORS 3 /* sent by mapper, asking for a list */
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/* of this router's neighbors */
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#define DVMRP_NEIGHBORS 4 /* response to such a request */
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#define DVMRP_ASK_NEIGHBORS2 5 /* as above, want new format reply */
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#define DVMRP_NEIGHBORS2 6
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#define DVMRP_PRUNE 7 /* prune message */
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#define DVMRP_GRAFT 8 /* graft message */
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#define DVMRP_GRAFT_ACK 9 /* graft acknowledgement */
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/*
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* 'flags' byte values in DVMRP_NEIGHBORS2 reply.
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*/
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#define DVMRP_NF_TUNNEL 0x01 /* neighbors reached via tunnel */
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#define DVMRP_NF_SRCRT 0x02 /* tunnel uses IP source routing */
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#define DVMRP_NF_DOWN 0x10 /* kernel state of interface */
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#define DVMRP_NF_DISABLED 0x20 /* administratively disabled */
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#define DVMRP_NF_QUERIER 0x40 /* I am the subnet's querier */
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static int print_probe(const u_char *, const u_char *, u_int);
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static int print_report(const u_char *, const u_char *, u_int);
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static int print_neighbors(const u_char *, const u_char *, u_int);
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static int print_neighbors2(const u_char *, const u_char *, u_int);
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static int print_prune(const u_char *);
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static int print_graft(const u_char *);
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static int print_graft_ack(const u_char *);
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static u_int32_t target_level;
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void
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dvmrp_print(register const u_char *bp, register u_int len)
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{
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register const u_char *ep;
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register u_char type;
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ep = (const u_char *)snapend;
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if (bp >= ep)
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return;
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TCHECK(bp[1]);
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type = bp[1];
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/* Skip IGMP header */
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bp += 8;
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len -= 8;
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switch (type) {
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case DVMRP_PROBE:
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printf(" Probe");
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if (vflag) {
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if (print_probe(bp, ep, len) < 0)
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goto trunc;
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}
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break;
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case DVMRP_REPORT:
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printf(" Report");
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if (vflag > 1) {
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if (print_report(bp, ep, len) < 0)
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goto trunc;
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}
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break;
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case DVMRP_ASK_NEIGHBORS:
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printf(" Ask-neighbors(old)");
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break;
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case DVMRP_NEIGHBORS:
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printf(" Neighbors(old)");
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if (print_neighbors(bp, ep, len) < 0)
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goto trunc;
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break;
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case DVMRP_ASK_NEIGHBORS2:
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printf(" Ask-neighbors2");
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break;
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case DVMRP_NEIGHBORS2:
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printf(" Neighbors2");
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/*
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* extract version and capabilities from IGMP group
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* address field
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*/
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bp -= 4;
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TCHECK2(bp[0], 4);
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target_level = (bp[0] << 24) | (bp[1] << 16) |
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(bp[2] << 8) | bp[3];
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bp += 4;
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if (print_neighbors2(bp, ep, len) < 0)
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goto trunc;
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break;
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case DVMRP_PRUNE:
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printf(" Prune");
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if (print_prune(bp) < 0)
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goto trunc;
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break;
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case DVMRP_GRAFT:
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printf(" Graft");
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if (print_graft(bp) < 0)
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goto trunc;
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break;
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case DVMRP_GRAFT_ACK:
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printf(" Graft-ACK");
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if (print_graft_ack(bp) < 0)
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goto trunc;
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break;
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default:
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printf(" [type %d]", type);
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break;
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}
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return;
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trunc:
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printf("[|dvmrp]");
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return;
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}
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static int
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print_report(register const u_char *bp, register const u_char *ep,
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register u_int len)
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{
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register u_int32_t mask, origin;
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register int metric, done;
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register u_int i, width;
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while (len > 0) {
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if (len < 3) {
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printf(" [|]");
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return (0);
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}
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TCHECK2(bp[0], 3);
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mask = (u_int32_t)0xff << 24 | bp[0] << 16 | bp[1] << 8 | bp[2];
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width = 1;
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if (bp[0])
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width = 2;
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if (bp[1])
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width = 3;
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if (bp[2])
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width = 4;
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printf("\n\tMask %s", intoa(htonl(mask)));
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bp += 3;
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len -= 3;
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do {
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if (bp + width + 1 > ep) {
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printf(" [|]");
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return (0);
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}
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if (len < width + 1) {
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printf("\n\t [Truncated Report]");
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return (0);
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}
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origin = 0;
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for (i = 0; i < width; ++i) {
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TCHECK(*bp);
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origin = origin << 8 | *bp++;
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}
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for ( ; i < 4; ++i)
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origin <<= 8;
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TCHECK(*bp);
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metric = *bp++;
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done = metric & 0x80;
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metric &= 0x7f;
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printf("\n\t %s metric %d", intoa(htonl(origin)),
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metric);
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len -= width + 1;
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} while (!done);
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}
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_probe(register const u_char *bp, register const u_char *ep,
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register u_int len)
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{
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register u_int32_t genid;
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TCHECK2(bp[0], 4);
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if ((len < 4) || ((bp + 4) > ep)) {
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/* { (ctags) */
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printf(" [|}");
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return (0);
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}
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genid = (bp[0] << 24) | (bp[1] << 16) | (bp[2] << 8) | bp[3];
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bp += 4;
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len -= 4;
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if (vflag > 1)
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printf("\n\t");
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else
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printf(" ");
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printf("genid %u", genid);
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if (vflag < 2)
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return (0);
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while ((len > 0) && (bp < ep)) {
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TCHECK2(bp[0], 4);
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printf("\n\tneighbor %s", ipaddr_string(bp));
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bp += 4; len -= 4;
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}
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_neighbors(register const u_char *bp, register const u_char *ep,
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register u_int len)
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{
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const u_char *laddr;
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register u_char metric;
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register u_char thresh;
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register int ncount;
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while (len > 0 && bp < ep) {
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TCHECK2(bp[0], 7);
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laddr = bp;
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bp += 4;
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metric = *bp++;
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thresh = *bp++;
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ncount = *bp++;
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len -= 7;
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while (--ncount >= 0) {
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TCHECK2(bp[0], 4);
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printf(" [%s ->", ipaddr_string(laddr));
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printf(" %s, (%d/%d)]",
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ipaddr_string(bp), metric, thresh);
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bp += 4;
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len -= 4;
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}
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}
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_neighbors2(register const u_char *bp, register const u_char *ep,
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register u_int len)
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{
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const u_char *laddr;
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register u_char metric, thresh, flags;
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register int ncount;
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printf(" (v %d.%d):",
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(int)target_level & 0xff,
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(int)(target_level >> 8) & 0xff);
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while (len > 0 && bp < ep) {
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TCHECK2(bp[0], 8);
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laddr = bp;
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bp += 4;
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metric = *bp++;
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thresh = *bp++;
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flags = *bp++;
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ncount = *bp++;
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len -= 8;
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while (--ncount >= 0 && (len >= 4) && (bp + 4) <= ep) {
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printf(" [%s -> ", ipaddr_string(laddr));
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printf("%s (%d/%d", ipaddr_string(bp),
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metric, thresh);
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if (flags & DVMRP_NF_TUNNEL)
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printf("/tunnel");
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if (flags & DVMRP_NF_SRCRT)
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printf("/srcrt");
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if (flags & DVMRP_NF_QUERIER)
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printf("/querier");
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if (flags & DVMRP_NF_DISABLED)
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printf("/disabled");
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if (flags & DVMRP_NF_DOWN)
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printf("/down");
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printf(")]");
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bp += 4;
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len -= 4;
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}
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if (ncount != -1) {
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printf(" [|]");
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return (0);
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}
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}
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_prune(register const u_char *bp)
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{
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TCHECK2(bp[0], 12);
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printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
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bp += 8;
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(void)printf(" timer ");
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relts_print(EXTRACT_32BITS(bp));
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_graft(register const u_char *bp)
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{
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TCHECK2(bp[0], 8);
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printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
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return (0);
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trunc:
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return (-1);
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}
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static int
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print_graft_ack(register const u_char *bp)
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{
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TCHECK2(bp[0], 8);
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printf(" src %s grp %s", ipaddr_string(bp), ipaddr_string(bp + 4));
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return (0);
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trunc:
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return (-1);
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}
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