epan/dissectors/packet-pktgen.c

   1 /* packet-pktgen.c
   2  * Routines for "Linux pktgen" dissection
   3  * Copyright 2006 _FF_
   4  * Francesco Fondelli <francesco dot fondelli, gmail dot com>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 /* FF:
  14  * The linux packet generator is a tool to generate packets at very high speed in the kernel.
  15  * See linux/net/core/pktgen.c and linux/Documentation/networking/pktgen.txt for more info.
  16  */
  17
  18 #include "config.h"
  19
  20 #include <epan/packet.h>
  21
  22 void proto_register_pktgen(void);
  23 void proto_reg_handoff_pktgen(void);
  24
  25 /* magic num used for heuristic */
  26 #define PKTGEN_MAGIC 0xbe9be955
  27
  28 /* Initialize the protocol and registered fields */
  29 static int proto_pktgen;
  30
  31 /* pktgen header */
  32 static int hf_pktgen_magic;
  33 static int hf_pktgen_seqnum;
  34 static int hf_pktgen_tvsec;
  35 static int hf_pktgen_tvusec;
  36 static int hf_pktgen_timestamp;
  37
  38 /* Initialize the subtree pointer */
  39 static int ett_pktgen;
  40
  41 /* entry point */
  42 static bool dissect_pktgen(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  43 {
  44     proto_item *ti          = NULL;
  45     proto_item *tmp         = NULL;
  46     proto_tree *pktgen_tree = NULL;
  47     uint32_t    offset      = 0;
  48     nstime_t    tstamp;
  49     uint32_t    magic;
  50
  51     /* check for min size */
  52     if (tvb_reported_length(tvb) < 16) {  /* Not a PKTGEN packet. */
  53         return false;
  54     }
  55
  56     /* check for magic number */
  57     magic = tvb_get_ntohl(tvb,0);
  58     if (magic != PKTGEN_MAGIC) {
  59         /* Not a PKTGEN packet. */
  60         return false;
  61     }
  62
  63
  64     /* Make entries in Protocol column and Info column on summary display */
  65
  66     col_set_str(pinfo->cinfo, COL_PROTOCOL, "PKTGEN");
  67
  68     col_add_fstr(pinfo->cinfo, COL_INFO, "Seq: %u", tvb_get_ntohl(tvb, 4));
  69
  70     if (tree) {
  71
  72         /* create display subtree for the protocol */
  73
  74         ti = proto_tree_add_item(tree, proto_pktgen, tvb, 0, -1, ENC_NA);
  75
  76         pktgen_tree = proto_item_add_subtree(ti, ett_pktgen);
  77
  78         /* add items to the subtree */
  79
  80         proto_tree_add_item(pktgen_tree, hf_pktgen_magic, tvb, offset, 4, ENC_BIG_ENDIAN);
  81         offset += 4;
  82
  83         proto_tree_add_item(pktgen_tree, hf_pktgen_seqnum, tvb, offset, 4, ENC_BIG_ENDIAN);
  84         offset += 4;
  85
  86         tstamp.secs = tvb_get_ntohl(tvb, offset);
  87         tmp = proto_tree_add_item(pktgen_tree, hf_pktgen_tvsec, tvb, offset, 4, ENC_BIG_ENDIAN);
  88         proto_item_set_generated(tmp);
  89         offset += 4;
  90
  91         tstamp.nsecs = tvb_get_ntohl(tvb, offset) /* microsecond on the wire so... */ * 1000;
  92         tmp = proto_tree_add_item(pktgen_tree, hf_pktgen_tvusec, tvb, offset, 4, ENC_BIG_ENDIAN);
  93         proto_item_set_generated(tmp);
  94         offset += 4;
  95
  96         proto_tree_add_time(pktgen_tree, hf_pktgen_timestamp, tvb, offset - 8, 8, &tstamp);
  97
  98         if (tvb_reported_length_remaining(tvb, offset)) /* random data */
  99             call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo,
 100             pktgen_tree);
 101     }
 102
 103     return true;
 104 }
 105
 106
 107 /* Register the protocol with Wireshark */
 108 void proto_register_pktgen(void)
 109 {
 110     /* Setup list of header fields */
 111
 112     static hf_register_info hf[] = {
 113
 114         { &hf_pktgen_magic,
 115           {
 116               "Magic number", "pktgen.magic",
 117               FT_UINT32, BASE_HEX, NULL, 0x0,
 118               "The pktgen magic number", HFILL
 119           }
 120         },
 121
 122         { &hf_pktgen_seqnum,
 123           {
 124               "Sequence number", "pktgen.seqnum",
 125               FT_UINT32, BASE_DEC, NULL, 0x0,
 126               NULL, HFILL
 127           }
 128         },
 129
 130         { &hf_pktgen_tvsec,
 131           {
 132               "Timestamp tvsec", "pktgen.tvsec",
 133               FT_UINT32, BASE_DEC, NULL, 0x0,
 134               "Timestamp tvsec part", HFILL
 135           }
 136         },
 137
 138         { &hf_pktgen_tvusec,
 139           {
 140               "Timestamp tvusec", "pktgen.tvusec",
 141               FT_UINT32, BASE_DEC, NULL, 0x0,
 142               "Timestamp tvusec part", HFILL
 143           }
 144         },
 145
 146         { &hf_pktgen_timestamp,
 147           {
 148               "Timestamp", "pktgen.timestamp",
 149               FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0,
 150               NULL, HFILL
 151           }
 152         }
 153     };
 154
 155     /* Setup protocol subtree array */
 156
 157     static int *ett[] = {
 158         &ett_pktgen
 159     };
 160
 161     /* Register the protocol name and description */
 162
 163     proto_pktgen = proto_register_protocol("Linux Kernel Packet Generator", "PKTGEN", "pktgen");
 164
 165     /* Required function calls to register the header fields and subtrees used */
 166
 167     proto_register_field_array(proto_pktgen, hf, array_length(hf));
 168     proto_register_subtree_array(ett, array_length(ett));
 169 }
 170
 171
 172 void proto_reg_handoff_pktgen(void)
 173 {
 174     /* Register as a heuristic UDP dissector */
 175     heur_dissector_add("udp", dissect_pktgen, "Linux Kernel Packet Generator over UDP", "pktgen_udp", proto_pktgen, HEURISTIC_ENABLE);
 176 }
 177
 178
 179 /*
 180  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 181  *
 182  * Local variables:
 183  * c-basic-offset: 4
 184  * tab-width: 8
 185  * indent-tabs-mode: nil
 186  * End:
 187  *
 188  * vi: set shiftwidth=4 tabstop=8 expandtab:
 189  * :indentSize=4:tabSize=8:noTabs=true:
 190  */