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![Joseph Mingrone](/assets/img/avatar_default.png)
Local changes: - Update some local modifications to fix build - Synch config.h with upstream as much as possible Changelog: https://git.tcpdump.org/tcpdump/blob/55bc126b0216cfe409b8d6bd378f65679d136ddf:/CHANGES Reviewed by: emaste Obtained from: https://www.tcpdump.org/release/tcpdump-4.99.4.tar.gz Sponsored by: The FreeBSD Foundation
503 lines
13 KiB
C
503 lines
13 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, nd_ipv6 *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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u_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 ip6_srh *srh;
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const u_char *p;
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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 = GET_U_1(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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advance = (GET_U_1(cp + 1) + 1) << 3;
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nh = GET_U_1(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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advance = sizeof(struct ip6_frag);
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nh = GET_U_1(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_SIZE(dp);
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len = GET_U_1(dp->ip6r_len);
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switch (GET_U_1(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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p = (const u_char *) dp0->ip6r0_addr;
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for (i = 0; i < len; i++) {
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ND_TCHECK_16(p);
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dst_addr = (const void *)p;
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p += 16;
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}
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break;
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case IPV6_RTHDR_TYPE_4:
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/* IPv6 Segment Routing Header (SRH) */
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srh = (const struct ip6_srh *)dp;
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if (len % 2 == 1)
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goto trunc;
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p = (const u_char *) srh->srh_segments;
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/*
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* The list of segments are encoded in the reverse order.
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* Accordingly, the final DA is encoded in srh_segments[0]
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*/
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ND_TCHECK_16(p);
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dst_addr = (const void *)p;
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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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GET_CPY_BYTES(dst, dst_addr, sizeof(nd_ipv6));
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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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uint16_t
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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, uint8_t next_proto)
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{
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struct {
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nd_ipv6 ph_src;
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nd_ipv6 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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u_int nh;
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/* pseudo-header */
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memset(&ph, 0, sizeof(ph));
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GET_CPY_BYTES(&ph.ph_src, ip6->ip6_src, sizeof(nd_ipv6));
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nh = GET_U_1(ip6->ip6_nxt);
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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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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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GET_CPY_BYTES(&ph.ph_dst, ip6->ip6_dst, sizeof(nd_ipv6));
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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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const struct ip6_hdr *ip6;
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int advance;
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u_int len;
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u_int total_advance;
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const u_char *cp;
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uint32_t payload_len;
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uint8_t ph, nh;
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int fragmented = 0;
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u_int flow;
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int found_extension_header;
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int found_jumbo;
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int found_hbh;
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ndo->ndo_protocol = "ip6";
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ip6 = (const struct ip6_hdr *)bp;
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ND_TCHECK_SIZE(ip6);
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if (length < sizeof (struct ip6_hdr)) {
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ND_PRINT("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("IP6 ");
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if (IP6_VERSION(ip6) != 6) {
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ND_PRINT("version error: %u != 6", IP6_VERSION(ip6));
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return;
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}
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payload_len = GET_BE_U_2(ip6->ip6_plen);
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/*
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* RFC 1883 says:
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*
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* The Payload Length field in the IPv6 header must be set to zero
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* in every packet that carries the Jumbo Payload option. If a
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* packet is received with a valid Jumbo Payload option present and
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* a non-zero IPv6 Payload Length field, an ICMP Parameter Problem
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* message, Code 0, should be sent to the packet's source, pointing
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* to the Option Type field of the Jumbo Payload option.
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*
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* Later versions of the IPv6 spec don't discuss the Jumbo Payload
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* option.
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*
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* If the payload length is 0, we temporarily just set the total
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* length to the remaining data in the packet (which, for Ethernet,
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* could include frame padding, but if it's a Jumbo Payload frame,
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* it shouldn't even be sendable over Ethernet, so we don't worry
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* about that), so we can process the extension headers in order
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* to *find* a Jumbo Payload hop-by-hop option and, when we've
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* processed all the extension headers, check whether we found
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* a Jumbo Payload option, and fail if we haven't.
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*/
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if (payload_len != 0) {
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len = payload_len + sizeof(struct ip6_hdr);
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if (length < len)
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ND_PRINT("truncated-ip6 - %u bytes missing!",
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len - length);
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} else
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len = length + sizeof(struct ip6_hdr);
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ph = 255;
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nh = GET_U_1(ip6->ip6_nxt);
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if (ndo->ndo_vflag) {
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flow = GET_BE_U_4(ip6->ip6_flow);
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ND_PRINT("(");
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/* RFC 2460 */
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if (flow & 0x0ff00000)
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ND_PRINT("class 0x%02x, ", (flow & 0x0ff00000) >> 20);
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if (flow & 0x000fffff)
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ND_PRINT("flowlabel 0x%05x, ", flow & 0x000fffff);
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ND_PRINT("hlim %u, next-header %s (%u) payload length: %u) ",
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GET_U_1(ip6->ip6_hlim),
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tok2str(ipproto_values,"unknown",nh),
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nh,
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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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if (!nd_push_snaplen(ndo, bp, len)) {
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(*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
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"%s: can't push snaplen on buffer stack", __func__);
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}
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cp = (const u_char *)ip6;
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advance = sizeof(struct ip6_hdr);
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total_advance = 0;
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/* Process extension headers */
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found_extension_header = 0;
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found_jumbo = 0;
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found_hbh = 0;
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while (cp < ndo->ndo_snapend && advance > 0) {
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if (len < (u_int)advance)
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goto trunc;
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cp += advance;
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len -= advance;
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total_advance += 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("%s > %s: ", GET_IP6ADDR_STRING(ip6->ip6_src),
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GET_IP6ADDR_STRING(ip6->ip6_dst));
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}
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switch (nh) {
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case IPPROTO_HOPOPTS:
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/*
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* The Hop-by-Hop Options header, when present,
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* must immediately follow the IPv6 header (RFC 8200)
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*/
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if (found_hbh == 1) {
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ND_PRINT("[The Hop-by-Hop Options header was already found]");
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nd_print_invalid(ndo);
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return;
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}
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if (ph != 255) {
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ND_PRINT("[The Hop-by-Hop Options header don't follow the IPv6 header]");
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nd_print_invalid(ndo);
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return;
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}
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advance = hbhopt_process(ndo, cp, &found_jumbo, &payload_len);
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if (payload_len == 0 && found_jumbo == 0) {
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ND_PRINT("[No valid Jumbo Payload Hop-by-Hop option found]");
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nd_print_invalid(ndo);
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return;
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}
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if (advance < 0) {
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nd_pop_packet_info(ndo);
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return;
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}
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found_extension_header = 1;
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found_hbh = 1;
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nh = GET_U_1(cp);
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break;
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case IPPROTO_DSTOPTS:
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advance = dstopt_process(ndo, cp);
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if (advance < 0) {
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nd_pop_packet_info(ndo);
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return;
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}
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found_extension_header = 1;
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nh = GET_U_1(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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nd_pop_packet_info(ndo);
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return;
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}
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found_extension_header = 1;
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nh = GET_U_1(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 possibility 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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if (advance < 0) {
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nd_pop_packet_info(ndo);
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return;
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}
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found_extension_header = 1;
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nh = GET_U_1(cp);
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nd_pop_packet_info(ndo);
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return;
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case IPPROTO_ROUTING:
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ND_TCHECK_1(cp);
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advance = rt6_print(ndo, cp, (const u_char *)ip6);
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if (advance < 0) {
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nd_pop_packet_info(ndo);
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return;
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}
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found_extension_header = 1;
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nh = GET_U_1(cp);
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break;
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default:
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/*
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* Not an extension header; hand off to the
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* IP protocol demuxer.
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*/
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if (found_jumbo) {
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/*
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* We saw a Jumbo Payload option.
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* Set the length to the payload length
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* plus the IPv6 header length, and
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* change the snapshot length accordingly.
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*
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* But make sure it's not shorter than
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* the total number of bytes we've
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* processed so far.
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*/
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len = payload_len + sizeof(struct ip6_hdr);
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if (len < total_advance)
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goto trunc;
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if (length < len)
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ND_PRINT("truncated-ip6 - %u bytes missing!",
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len - length);
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nd_change_snaplen(ndo, bp, len);
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/*
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* Now subtract the length of the IPv6
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* header plus extension headers to get
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* the payload length.
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*/
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len -= total_advance;
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} else {
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/*
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* We didn't see a Jumbo Payload option;
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* was the payload length zero?
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*/
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if (payload_len == 0) {
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/*
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* Yes. If we found an extension
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* header, treat that as a truncated
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* packet header, as there was
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* no payload to contain an
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* extension header.
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*/
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if (found_extension_header)
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goto trunc;
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/*
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* OK, we didn't see any extension
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* header, but that means we have
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* no payload, so set the length
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* to the IPv6 header length,
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* and change the snapshot length
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* accordingly.
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*/
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len = sizeof(struct ip6_hdr);
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nd_change_snaplen(ndo, bp, len);
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/*
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* Now subtract the length of
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* the IPv6 header plus extension
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* headers (there weren't any, so
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* that's just the IPv6 header
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* length) to get the payload length.
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*/
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len -= total_advance;
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}
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}
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ip_demux_print(ndo, cp, len, 6, fragmented,
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GET_U_1(ip6->ip6_hlim), nh, bp);
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nd_pop_packet_info(ndo);
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return;
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}
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ph = nh;
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/* ndo_protocol reassignment after xxx_print() calls */
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ndo->ndo_protocol = "ip6";
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}
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nd_pop_packet_info(ndo);
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return;
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trunc:
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nd_print_trunc(ndo);
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}
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