mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-27 20:14:12 +08:00
4bce81542c
Make dst_addr a "const void *" to squelch
taking address of packed member 'ip6_dst' of class or structure
'ip6_hdr' may result in an unaligned pointer value
[-Waddress-of-packed-member]
warnings from some versions of Clang.
413 lines
10 KiB
C
413 lines
10 KiB
C
/*
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* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
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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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/* \summary: IPv6 printer */
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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 <netdissect-stdinc.h>
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#include <string.h>
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#include "netdissect.h"
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#include "addrtoname.h"
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#include "extract.h"
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#include "ip6.h"
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#include "ipproto.h"
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/*
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* If routing headers are presend and valid, set dst to the final destination.
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* Otherwise, set it to the IPv6 destination.
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*
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* This is used for UDP and TCP pseudo-header in the checksum
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* calculation.
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*/
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static void
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ip6_finddst(netdissect_options *ndo, struct in6_addr *dst,
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const struct ip6_hdr *ip6)
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{
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const u_char *cp;
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int advance;
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u_int nh;
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const void *dst_addr;
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const struct ip6_rthdr *dp;
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const struct ip6_rthdr0 *dp0;
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const struct in6_addr *addr;
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int i, len;
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cp = (const u_char *)ip6;
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advance = sizeof(struct ip6_hdr);
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nh = ip6->ip6_nxt;
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dst_addr = (const void *)&ip6->ip6_dst;
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while (cp < ndo->ndo_snapend) {
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cp += advance;
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switch (nh) {
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case IPPROTO_HOPOPTS:
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case IPPROTO_DSTOPTS:
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case IPPROTO_MOBILITY_OLD:
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case IPPROTO_MOBILITY:
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/*
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* These have a header length byte, following
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* the next header byte, giving the length of
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* the header, in units of 8 octets, excluding
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* the first 8 octets.
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*/
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ND_TCHECK2(*cp, 2);
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advance = (int)((*(cp + 1) + 1) << 3);
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nh = *cp;
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break;
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case IPPROTO_FRAGMENT:
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/*
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* The byte following the next header byte is
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* marked as reserved, and the header is always
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* the same size.
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*/
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ND_TCHECK2(*cp, 1);
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advance = sizeof(struct ip6_frag);
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nh = *cp;
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break;
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case IPPROTO_ROUTING:
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/*
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* OK, we found it.
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*/
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dp = (const struct ip6_rthdr *)cp;
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ND_TCHECK(*dp);
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len = dp->ip6r_len;
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switch (dp->ip6r_type) {
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case IPV6_RTHDR_TYPE_0:
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case IPV6_RTHDR_TYPE_2: /* Mobile IPv6 ID-20 */
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dp0 = (const struct ip6_rthdr0 *)dp;
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if (len % 2 == 1)
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goto trunc;
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len >>= 1;
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addr = &dp0->ip6r0_addr[0];
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for (i = 0; i < len; i++) {
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if ((const u_char *)(addr + 1) > ndo->ndo_snapend)
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goto trunc;
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dst_addr = (const void *)addr;
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addr++;
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}
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break;
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default:
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break;
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}
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/*
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* Only one routing header to a customer.
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*/
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goto done;
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case IPPROTO_AH:
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case IPPROTO_ESP:
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case IPPROTO_IPCOMP:
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default:
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/*
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* AH and ESP are, in the RFCs that describe them,
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* described as being "viewed as an end-to-end
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* payload" "in the IPv6 context, so that they
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* "should appear after hop-by-hop, routing, and
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* fragmentation extension headers". We assume
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* that's the case, and stop as soon as we see
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* one. (We can't handle an ESP header in
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* the general case anyway, as its length depends
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* on the encryption algorithm.)
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*
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* IPComp is also "viewed as an end-to-end
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* payload" "in the IPv6 context".
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*
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* All other protocols are assumed to be the final
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* protocol.
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*/
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goto done;
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}
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}
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done:
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trunc:
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UNALIGNED_MEMCPY(dst, dst_addr, sizeof(struct in6_addr));
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}
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/*
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* Compute a V6-style checksum by building a pseudoheader.
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*/
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int
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nextproto6_cksum(netdissect_options *ndo,
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const struct ip6_hdr *ip6, const uint8_t *data,
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u_int len, u_int covlen, u_int next_proto)
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{
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struct {
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struct in6_addr ph_src;
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struct in6_addr ph_dst;
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uint32_t ph_len;
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uint8_t ph_zero[3];
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uint8_t ph_nxt;
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} ph;
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struct cksum_vec vec[2];
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/* pseudo-header */
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memset(&ph, 0, sizeof(ph));
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UNALIGNED_MEMCPY(&ph.ph_src, &ip6->ip6_src, sizeof (struct in6_addr));
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switch (ip6->ip6_nxt) {
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case IPPROTO_HOPOPTS:
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case IPPROTO_DSTOPTS:
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case IPPROTO_MOBILITY_OLD:
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case IPPROTO_MOBILITY:
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case IPPROTO_FRAGMENT:
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case IPPROTO_ROUTING:
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/*
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* The next header is either a routing header or a header
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* after which there might be a routing header, so scan
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* for a routing header.
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*/
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ip6_finddst(ndo, &ph.ph_dst, ip6);
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break;
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default:
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UNALIGNED_MEMCPY(&ph.ph_dst, &ip6->ip6_dst, sizeof (struct in6_addr));
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break;
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}
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ph.ph_len = htonl(len);
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ph.ph_nxt = next_proto;
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vec[0].ptr = (const uint8_t *)(void *)&ph;
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vec[0].len = sizeof(ph);
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vec[1].ptr = data;
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vec[1].len = covlen;
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return in_cksum(vec, 2);
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}
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/*
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* print an IP6 datagram.
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*/
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void
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ip6_print(netdissect_options *ndo, const u_char *bp, u_int length)
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{
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register const struct ip6_hdr *ip6;
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register int advance;
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u_int len;
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const u_char *ipend;
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register const u_char *cp;
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register u_int payload_len;
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int nh;
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int fragmented = 0;
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u_int flow;
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ip6 = (const struct ip6_hdr *)bp;
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ND_TCHECK(*ip6);
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if (length < sizeof (struct ip6_hdr)) {
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ND_PRINT((ndo, "truncated-ip6 %u", length));
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return;
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}
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if (!ndo->ndo_eflag)
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ND_PRINT((ndo, "IP6 "));
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if (IP6_VERSION(ip6) != 6) {
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ND_PRINT((ndo,"version error: %u != 6", IP6_VERSION(ip6)));
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return;
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}
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payload_len = EXTRACT_16BITS(&ip6->ip6_plen);
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len = payload_len + sizeof(struct ip6_hdr);
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if (length < len)
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ND_PRINT((ndo, "truncated-ip6 - %u bytes missing!",
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len - length));
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if (ndo->ndo_vflag) {
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flow = EXTRACT_32BITS(&ip6->ip6_flow);
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ND_PRINT((ndo, "("));
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#if 0
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/* rfc1883 */
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if (flow & 0x0f000000)
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ND_PRINT((ndo, "pri 0x%02x, ", (flow & 0x0f000000) >> 24));
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if (flow & 0x00ffffff)
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ND_PRINT((ndo, "flowlabel 0x%06x, ", flow & 0x00ffffff));
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#else
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/* RFC 2460 */
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if (flow & 0x0ff00000)
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ND_PRINT((ndo, "class 0x%02x, ", (flow & 0x0ff00000) >> 20));
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if (flow & 0x000fffff)
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ND_PRINT((ndo, "flowlabel 0x%05x, ", flow & 0x000fffff));
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#endif
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ND_PRINT((ndo, "hlim %u, next-header %s (%u) payload length: %u) ",
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ip6->ip6_hlim,
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tok2str(ipproto_values,"unknown",ip6->ip6_nxt),
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ip6->ip6_nxt,
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payload_len));
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}
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/*
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* Cut off the snapshot length to the end of the IP payload.
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*/
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ipend = bp + len;
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if (ipend < ndo->ndo_snapend)
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ndo->ndo_snapend = ipend;
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cp = (const u_char *)ip6;
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advance = sizeof(struct ip6_hdr);
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nh = ip6->ip6_nxt;
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while (cp < ndo->ndo_snapend && advance > 0) {
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cp += advance;
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len -= advance;
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if (cp == (const u_char *)(ip6 + 1) &&
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nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
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nh != IPPROTO_DCCP && nh != IPPROTO_SCTP) {
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ND_PRINT((ndo, "%s > %s: ", ip6addr_string(ndo, &ip6->ip6_src),
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ip6addr_string(ndo, &ip6->ip6_dst)));
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}
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switch (nh) {
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case IPPROTO_HOPOPTS:
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advance = hbhopt_print(ndo, cp);
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if (advance < 0)
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return;
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nh = *cp;
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break;
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case IPPROTO_DSTOPTS:
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advance = dstopt_print(ndo, cp);
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if (advance < 0)
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return;
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nh = *cp;
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break;
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case IPPROTO_FRAGMENT:
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advance = frag6_print(ndo, cp, (const u_char *)ip6);
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if (advance < 0 || ndo->ndo_snapend <= cp + advance)
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return;
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nh = *cp;
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fragmented = 1;
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break;
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case IPPROTO_MOBILITY_OLD:
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case IPPROTO_MOBILITY:
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/*
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* XXX - we don't use "advance"; RFC 3775 says that
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* the next header field in a mobility header
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* should be IPPROTO_NONE, but speaks of
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* the possiblity of a future extension in
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* which payload can be piggybacked atop a
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* mobility header.
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*/
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advance = mobility_print(ndo, cp, (const u_char *)ip6);
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nh = *cp;
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return;
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case IPPROTO_ROUTING:
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advance = rt6_print(ndo, cp, (const u_char *)ip6);
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nh = *cp;
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break;
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case IPPROTO_SCTP:
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sctp_print(ndo, cp, (const u_char *)ip6, len);
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return;
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case IPPROTO_DCCP:
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dccp_print(ndo, cp, (const u_char *)ip6, len);
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return;
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case IPPROTO_TCP:
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tcp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
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return;
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case IPPROTO_UDP:
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udp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
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return;
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case IPPROTO_ICMPV6:
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icmp6_print(ndo, cp, len, (const u_char *)ip6, fragmented);
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return;
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case IPPROTO_AH:
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advance = ah_print(ndo, cp);
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nh = *cp;
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break;
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case IPPROTO_ESP:
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{
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int enh, padlen;
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advance = esp_print(ndo, cp, len, (const u_char *)ip6, &enh, &padlen);
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nh = enh & 0xff;
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len -= padlen;
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break;
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}
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case IPPROTO_IPCOMP:
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{
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ipcomp_print(ndo, cp);
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/*
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* Either this has decompressed the payload and
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* printed it, in which case there's nothing more
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* to do, or it hasn't, in which case there's
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* nothing more to do.
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*/
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advance = -1;
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break;
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}
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case IPPROTO_PIM:
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pim_print(ndo, cp, len, (const u_char *)ip6);
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return;
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case IPPROTO_OSPF:
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ospf6_print(ndo, cp, len);
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return;
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case IPPROTO_IPV6:
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ip6_print(ndo, cp, len);
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return;
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case IPPROTO_IPV4:
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ip_print(ndo, cp, len);
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return;
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case IPPROTO_PGM:
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pgm_print(ndo, cp, len, (const u_char *)ip6);
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return;
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case IPPROTO_GRE:
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gre_print(ndo, cp, len);
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return;
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case IPPROTO_RSVP:
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rsvp_print(ndo, cp, len);
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return;
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case IPPROTO_NONE:
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ND_PRINT((ndo, "no next header"));
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return;
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default:
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ND_PRINT((ndo, "ip-proto-%d %d", nh, len));
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return;
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}
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}
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return;
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trunc:
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ND_PRINT((ndo, "[|ip6]"));
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}
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