mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-28 04:25:16 +08:00
8e396b5731
add support for variable-length checksum in DCCP, as per section 9 of RFC 4340. remove duplicated code in dccp6_cksum (which just repeated the code of in_cksum fix a bug in dccp.h -- the fields of CCVAL and CSCOV were swapped (see section 5.1 of RFC 4340) fix a typo in the display of incorrect checksums old output `cksum xDEAD (incorrect (-> xBEEF)', new output `cksum xDEAD (incorrect -> xBEEF)'
532 lines
12 KiB
C
532 lines
12 KiB
C
/*
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* Copyright (C) Arnaldo Carvalho de Melo 2004
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* Copyright (C) Ian McDonald 2005
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* Copyright (C) Yoshifumi Nishida 2005
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*
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* This software may be distributed either under the terms of the
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* BSD-style license that accompanies tcpdump or the GNU GPL version 2
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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-dccp.c,v 1.7 2006-11-02 09:05:23 hannes 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 "dccp.h"
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#include <stdio.h>
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#include <string.h>
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#include "interface.h"
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#include "addrtoname.h"
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#include "extract.h" /* must come after interface.h */
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#include "ip.h"
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#ifdef INET6
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#include "ip6.h"
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#endif
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#include "ipproto.h"
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static const char *dccp_reset_codes[] = {
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"unspecified",
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"closed",
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"aborted",
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"no_connection",
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"packet_error",
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"option_error",
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"mandatory_error",
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"connection_refused",
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"bad_service_code",
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"too_busy",
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"bad_init_cookie",
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"aggression_penalty",
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};
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static const char *dccp_feature_nums[] = {
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"reserved",
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"ccid",
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"allow_short_seqno",
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"sequence_window",
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"ecn_incapable",
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"ack_ratio",
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"send_ack_vector",
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"send_ndp_count",
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"minimum checksum coverage",
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"check data checksum",
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};
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static inline int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)
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{
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u_int cov;
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if (DCCPH_CSCOV(dh) == 0)
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return len;
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cov = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(u_int32_t);
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return (cov > len)? len : cov;
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}
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static int dccp_cksum(const struct ip *ip,
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const struct dccp_hdr *dh, u_int len)
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{
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int cov = dccp_csum_coverage(dh, len);
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union phu {
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struct phdr {
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u_int32_t src;
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u_int32_t dst;
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u_char mbz;
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u_char proto;
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u_int16_t len;
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} ph;
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u_int16_t pa[6];
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} phu;
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const u_int16_t *sp;
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/* pseudo-header.. */
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phu.ph.mbz = 0;
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phu.ph.len = htons(len);
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phu.ph.proto = IPPROTO_DCCP;
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memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
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if (IP_HL(ip) == 5)
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memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
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else
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phu.ph.dst = ip_finddst(ip);
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sp = &phu.pa[0];
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return in_cksum((u_short *)dh, cov, sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5]);
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}
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#ifdef INET6
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static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)
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{
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size_t i;
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u_int32_t sum = 0;
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int cov = dccp_csum_coverage(dh, len);
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union {
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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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u_int32_t ph_len;
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u_int8_t ph_zero[3];
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u_int8_t ph_nxt;
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} ph;
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u_int16_t pa[20];
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} phu;
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/* pseudo-header */
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memset(&phu, 0, sizeof(phu));
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phu.ph.ph_src = ip6->ip6_src;
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phu.ph.ph_dst = ip6->ip6_dst;
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phu.ph.ph_len = htonl(len);
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phu.ph.ph_nxt = IPPROTO_DCCP;
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for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
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sum += phu.pa[i];
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return in_cksum((u_short *)dh, cov, sum);
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}
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#endif
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static const char *dccp_reset_code(u_int8_t code)
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{
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if (code >= __DCCP_RESET_CODE_LAST)
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return "invalid";
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return dccp_reset_codes[code];
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}
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static u_int64_t dccp_seqno(const struct dccp_hdr *dh)
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{
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u_int32_t seq_high = DCCPH_SEQ(dh);
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u_int64_t seqno = EXTRACT_24BITS(&seq_high) & 0xFFFFFF;
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if (DCCPH_X(dh) != 0) {
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const struct dccp_hdr_ext *dhx = (void *)(dh + 1);
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u_int32_t seq_low = dhx->dccph_seq_low;
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seqno &= 0x00FFFF; /* clear reserved field */
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seqno = (seqno << 32) + EXTRACT_32BITS(&seq_low);
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}
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return seqno;
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}
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static inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
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{
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return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
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}
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static void dccp_print_ack_no(const u_char *bp)
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{
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const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
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const struct dccp_hdr_ack_bits *dh_ack =
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(struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
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u_int32_t ack_high;
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u_int64_t ackno;
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TCHECK2(*dh_ack,4);
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ack_high = DCCPH_ACK(dh_ack);
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ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
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if (DCCPH_X(dh) != 0) {
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u_int32_t ack_low;
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TCHECK2(*dh_ack,8);
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ack_low = dh_ack->dccph_ack_nr_low;
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ackno &= 0x00FFFF; /* clear reserved field */
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ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
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}
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(void)printf("(ack=%" PRIu64 ") ", ackno);
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trunc:
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return;
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}
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static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
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{
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if (type == DCCP_PKT_DATA)
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return 0;
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if (type == DCCP_PKT_DATAACK ||
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type == DCCP_PKT_ACK ||
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type == DCCP_PKT_SYNC ||
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type == DCCP_PKT_SYNCACK ||
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type == DCCP_PKT_CLOSE ||
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type == DCCP_PKT_CLOSEREQ)
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return sizeof(struct dccp_hdr_ack_bits);
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if (type == DCCP_PKT_REQUEST)
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return sizeof(struct dccp_hdr_request);
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if (type == DCCP_PKT_RESPONSE)
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return sizeof(struct dccp_hdr_response);
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return sizeof(struct dccp_hdr_reset);
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}
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static int dccp_print_option(const u_char *option);
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/**
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* dccp_print - show dccp packet
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* @bp - beginning of dccp packet
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* @data2 - beginning of enclosing
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* @len - lenght of ip packet
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*/
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void dccp_print(const u_char *bp, const u_char *data2, u_int len)
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{
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const struct dccp_hdr *dh;
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const struct ip *ip;
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#ifdef INET6
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const struct ip6_hdr *ip6;
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#endif
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const u_char *cp;
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u_short sport, dport;
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u_int hlen;
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u_int extlen = 0;
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dh = (const struct dccp_hdr *)bp;
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ip = (struct ip *)data2;
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#ifdef INET6
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if (IP_V(ip) == 6)
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ip6 = (const struct ip6_hdr *)data2;
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else
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ip6 = NULL;
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#endif /*INET6*/
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cp = (const u_char *)(dh + 1);
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if (cp > snapend) {
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printf("[Invalid packet|dccp]");
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return;
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}
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if (len < sizeof(struct dccp_hdr)) {
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printf("truncated-dccp - %ld bytes missing!",
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(long)len - sizeof(struct dccp_hdr));
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return;
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}
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sport = EXTRACT_16BITS(&dh->dccph_sport);
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dport = EXTRACT_16BITS(&dh->dccph_dport);
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hlen = dh->dccph_doff * 4;
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#ifdef INET6
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if (ip6) {
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(void)printf("%s.%d > %s.%d: ",
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ip6addr_string(&ip6->ip6_src), sport,
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ip6addr_string(&ip6->ip6_dst), dport);
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} else
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#endif /*INET6*/
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{
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(void)printf("%s.%d > %s.%d: ",
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ipaddr_string(&ip->ip_src), sport,
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ipaddr_string(&ip->ip_dst), dport);
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}
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fflush(stdout);
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if (qflag) {
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(void)printf(" %d", len - hlen);
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if (hlen > len) {
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(void)printf("dccp [bad hdr length %u - too long, > %u]",
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hlen, len);
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}
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return;
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}
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/* other variables in generic header */
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if (vflag) {
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(void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
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}
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/* checksum calculation */
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#ifdef INET6
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if (ip6) {
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if (ip6->ip6_plen && vflag) {
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u_int16_t sum, dccp_sum;
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sum = dccp6_cksum(ip6, dh, len);
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dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
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printf("cksum 0x%04x", dccp_sum);
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if (sum != 0) {
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(void)printf(" (incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
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} else
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(void)printf(" (correct), ");
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}
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} else
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#endif /* INET6 */
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if (vflag)
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{
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u_int16_t sum, dccp_sum;
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sum = dccp_cksum(ip, dh, len);
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dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
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printf("cksum 0x%04x", dccp_sum);
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if (sum != 0) {
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(void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
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} else
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(void)printf(" (correct), ");
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}
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switch (DCCPH_TYPE(dh)) {
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case DCCP_PKT_REQUEST: {
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struct dccp_hdr_request *dhr =
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(struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
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TCHECK(*dhr);
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(void)printf("request (service=%d) ",
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EXTRACT_32BITS(&dhr->dccph_req_service));
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extlen += 4;
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break;
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}
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case DCCP_PKT_RESPONSE: {
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struct dccp_hdr_response *dhr =
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(struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
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TCHECK(*dhr);
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(void)printf("response (service=%d) ",
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EXTRACT_32BITS(&dhr->dccph_resp_service));
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extlen += 12;
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break;
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}
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case DCCP_PKT_DATA:
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(void)printf("data ");
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break;
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case DCCP_PKT_ACK: {
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(void)printf("ack ");
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extlen += 8;
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break;
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}
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case DCCP_PKT_DATAACK: {
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(void)printf("dataack ");
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extlen += 8;
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break;
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}
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case DCCP_PKT_CLOSEREQ:
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(void)printf("closereq ");
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extlen += 8;
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break;
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case DCCP_PKT_CLOSE:
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(void)printf("close ");
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extlen += 8;
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break;
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case DCCP_PKT_RESET: {
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struct dccp_hdr_reset *dhr =
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(struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
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TCHECK(*dhr);
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(void)printf("reset (code=%s) ",
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dccp_reset_code(dhr->dccph_reset_code));
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extlen += 12;
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break;
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}
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case DCCP_PKT_SYNC:
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(void)printf("sync ");
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extlen += 8;
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break;
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case DCCP_PKT_SYNCACK:
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(void)printf("syncack ");
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extlen += 8;
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break;
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default:
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(void)printf("invalid ");
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break;
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}
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if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
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(DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
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dccp_print_ack_no(bp);
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if (vflag < 2)
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return;
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(void)printf("seq %" PRIu64, dccp_seqno(dh));
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/* process options */
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if (hlen > dccp_basic_hdr_len(dh) + extlen){
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const u_char *cp;
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u_int optlen;
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cp = bp + dccp_basic_hdr_len(dh) + extlen;
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printf(" <");
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hlen -= dccp_basic_hdr_len(dh) + extlen;
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while(1){
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TCHECK(*cp);
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optlen = dccp_print_option(cp);
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if (!optlen) goto trunc2;
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if (hlen <= optlen) break;
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hlen -= optlen;
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cp += optlen;
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printf(", ");
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}
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printf(">");
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}
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return;
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trunc:
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printf("[|dccp]");
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trunc2:
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return;
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}
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static int dccp_print_option(const u_char *option)
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{
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u_int8_t optlen, i;
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u_int32_t *ts;
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u_int16_t *var16;
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u_int32_t *var32;
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TCHECK(*option);
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if (*option >= 32) {
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TCHECK(*(option+1));
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optlen = *(option +1);
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if (optlen < 2) {
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printf("Option %d optlen too short",*option);
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return 1;
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}
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} else optlen = 1;
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TCHECK2(*option,optlen);
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switch (*option){
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case 0:
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printf("nop");
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break;
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case 1:
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printf("mandatory");
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break;
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case 2:
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printf("slowreceiver");
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break;
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case 32:
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printf("change_l");
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if (*(option +2) < 10){
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printf(" %s", dccp_feature_nums[*(option +2)]);
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for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
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}
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break;
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case 33:
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printf("confirm_l");
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if (*(option +2) < 10){
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printf(" %s", dccp_feature_nums[*(option +2)]);
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for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
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}
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break;
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case 34:
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printf("change_r");
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if (*(option +2) < 10){
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printf(" %s", dccp_feature_nums[*(option +2)]);
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for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
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}
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break;
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case 35:
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printf("confirm_r");
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if (*(option +2) < 10){
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printf(" %s", dccp_feature_nums[*(option +2)]);
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for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
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}
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break;
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case 36:
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printf("initcookie 0x");
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for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
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break;
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case 37:
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printf("ndp_count");
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for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
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break;
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case 38:
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printf("ack_vector0 0x");
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for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
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break;
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case 39:
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printf("ack_vector1 0x");
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for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
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break;
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case 40:
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printf("data_dropped 0x");
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for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
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break;
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case 41:
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ts = (u_int32_t *)(option + 2);
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printf("timestamp %u", (u_int32_t)ntohl(*ts));
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break;
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case 42:
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ts = (u_int32_t *)(option + 2);
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printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
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break;
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case 43:
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printf("elapsed_time ");
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if (optlen == 6){
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ts = (u_int32_t *)(option + 2);
|
|
printf("%u", (u_int32_t)ntohl(*ts));
|
|
} else {
|
|
var16 = (u_int16_t *)(option + 2);
|
|
printf("%u", ntohs(*var16));
|
|
}
|
|
break;
|
|
case 44:
|
|
printf("data_checksum ");
|
|
for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
|
|
break;
|
|
default :
|
|
if (*option >= 128) {
|
|
printf("CCID option %d",*option);
|
|
switch (optlen) {
|
|
case 4:
|
|
var16 = (u_int16_t *)(option + 2);
|
|
printf(" %u",ntohs(*var16));
|
|
break;
|
|
case 6:
|
|
var32 = (u_int32_t *)(option + 2);
|
|
printf(" %u",(u_int32_t)ntohl(*var32));
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
|
|
printf("unknown_opt %d", *option);
|
|
break;
|
|
}
|
|
|
|
return optlen;
|
|
trunc:
|
|
printf("[|dccp]");
|
|
return 0;
|
|
}
|