The Tcpdump Group git mirrors - tcpdump/blob - dccp.h

   1 #ifndef __DCCP_HDR__
   2 #define __DCCP_HDR__
   3 /*
   4  * Copyright (C) Arnaldo Carvalho de Melo 2004
   5  * Copyright (C) Ian McDonald 2005 <iam4@cs.waikato.ac.nz>
   6  * Copyright (C) Yoshifumi Nishida 2005
   7  *
   8  * This software may be distributed either under the terms of the
   9  * BSD-style license that accompanies tcpdump or the GNU GPL version 2
  10  */
  11
  12 /**
  13  * struct dccp_hdr - generic part of DCCP packet header
  14  *
  15  * @dccph_sport - Relevant port on the endpoint that sent this packet
  16  * @dccph_dport - Relevant port on the other endpoint
  17  * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
  18  * @dccph_ccval - Used by the HC-Sender CCID
  19  * @dccph_cscov - Parts of the packet that are covered by the Checksum field
  20  * @dccph_checksum - Internet checksum, depends on dccph_cscov
  21  * @dccph_x - 0 = 24 bit sequence number, 1 = 48
  22  * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
  23  * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
  24  */
  25 struct dccp_hdr {
  26         u_int16_t       dccph_sport,
  27                         dccph_dport;
  28         u_int8_t        dccph_doff;
  29         u_int8_t        dccph_ccval_cscov;
  30         u_int16_t       dccph_checksum;
  31         union {
  32         u_int8_t        dccph_xtr;
  33         u_int32_t       dccph_seq;
  34         }               dccph_xtrs;
  35 };
  36
  37 #define DCCPH_CCVAL(dh) (((dh)->dccph_ccval_cscov) & 0x0F)
  38 #define DCCPH_CSCOV(dh) (((dh)->dccph_ccval_cscov >> 4) & 0x0F)
  39
  40 #define DCCPH_X(dh)     ((dh)->dccph_xtrs.dccph_xtr & 1)
  41 #define DCCPH_TYPE(dh)  (((dh)->dccph_xtrs.dccph_xtr >> 1) & 0xF)
  42 #define DCCPH_SEQ(dh)   (((dh)->dccph_xtrs.dccph_seq) >> 8)
  43
  44 /**
  45  * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
  46  *
  47  * @dccph_seq_low - low 24 bits of a 48 bit seq packet
  48  */
  49 struct dccp_hdr_ext {
  50         u_int32_t       dccph_seq_low;
  51 };
  52
  53 /**
  54  * struct dccp_hdr_request - Conection initiation request header
  55  *
  56  * @dccph_req_service - Service to which the client app wants to connect
  57  */
  58 struct dccp_hdr_request {
  59         u_int32_t       dccph_req_service;
  60 };
  61
  62 /**
  63  * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
  64  *
  65  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
  66  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
  67  */
  68 struct dccp_hdr_ack_bits {
  69         u_int32_t       dccph_ra;
  70         u_int32_t       dccph_ack_nr_low;
  71 };
  72
  73 #define DCCPH_ACK(dh_ack)   ((dh_ack)->dccph_ra >> 8)
  74
  75 /**
  76  * struct dccp_hdr_response - Conection initiation response header
  77  *
  78  * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
  79  * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
  80  * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
  81  */
  82 struct dccp_hdr_response {
  83         struct dccp_hdr_ack_bits        dccph_resp_ack;
  84         u_int32_t                       dccph_resp_service;
  85 };
  86
  87 static inline struct dccp_hdr_data *dccp_hdr_data(struct dccp_hdr *hdrg)
  88 {
  89         const int ext = DCCPH_X(hdrg) ? sizeof(struct dccp_hdr_ext) : 0;
  90
  91         return (struct dccp_hdr_data *)(((u_char *)hdrg) + sizeof(hdrg) + ext);
  92 }
  93
  94 /**
  95  * struct dccp_hdr_reset - Unconditionally shut down a connection
  96  *
  97  * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
  98  */
  99 struct dccp_hdr_reset {
 100         struct dccp_hdr_ack_bits        dccph_reset_ack;
 101         u_int8_t                        dccph_reset_code,
 102                                         dccph_reset_data[3];
 103 };
 104
 105 enum dccp_pkt_type {
 106         DCCP_PKT_REQUEST = 0,
 107         DCCP_PKT_RESPONSE,
 108         DCCP_PKT_DATA,
 109         DCCP_PKT_ACK,
 110         DCCP_PKT_DATAACK,
 111         DCCP_PKT_CLOSEREQ,
 112         DCCP_PKT_CLOSE,
 113         DCCP_PKT_RESET,
 114         DCCP_PKT_SYNC,
 115         DCCP_PKT_SYNCACK,
 116         DCCP_PKT_INVALID,
 117 };
 118
 119 enum dccp_reset_codes {
 120         DCCP_RESET_CODE_UNSPECIFIED = 0,
 121         DCCP_RESET_CODE_CLOSED,
 122         DCCP_RESET_CODE_ABORTED,
 123         DCCP_RESET_CODE_NO_CONNECTION,
 124         DCCP_RESET_CODE_PACKET_ERROR,
 125         DCCP_RESET_CODE_OPTION_ERROR,
 126         DCCP_RESET_CODE_MANDATORY_ERROR,
 127         DCCP_RESET_CODE_CONNECTION_REFUSED,
 128         DCCP_RESET_CODE_BAD_SERVICE_CODE,
 129         DCCP_RESET_CODE_TOO_BUSY,
 130         DCCP_RESET_CODE_BAD_INIT_COOKIE,
 131         DCCP_RESET_CODE_AGGRESSION_PENALTY,
 132         __DCCP_RESET_CODE_LAST,
 133 };
 134
 135 #endif /* __DCCP_HDR__ */