epan/dissectors/packet-finger.c

   1 /* packet-finger.c
   2  * Routines for basic finger dissection (see https://tools.ietf.org/html/rfc742)
   3  * Copyright 2013, Christopher Maynard <Christopher.Maynard@gtech.com>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13 #include <epan/packet.h>
  14 #include <epan/conversation.h>
  15 #include <epan/expert.h>
  16
  17 #include "packet-tcp.h"
  18
  19 void proto_register_finger(void);
  20 void proto_reg_handoff_finger(void);
  21
  22 static dissector_handle_t finger_handle;
  23
  24 #define FINGER_PORT     79  /* This is the registered IANA port */
  25
  26 static int proto_finger;
  27 static int hf_finger_query;
  28 static int hf_finger_response;
  29 static int hf_finger_response_in;
  30 static int hf_finger_response_to;
  31 static int hf_finger_response_time;
  32
  33 static expert_field ei_finger_nocrlf;
  34
  35 static int ett_finger;
  36
  37 typedef struct _finger_transaction_t {
  38     uint32_t req_frame;
  39     uint32_t rep_frame;
  40     nstime_t req_time;
  41 } finger_transaction_t;
  42
  43 static int
  44 dissect_finger(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
  45     void *data)
  46 {
  47     proto_item           *ti, *expert_ti;
  48     proto_tree           *finger_tree;
  49     conversation_t       *conversation;
  50     finger_transaction_t *finger_trans;
  51     bool                  is_query;
  52     unsigned              len;
  53     struct tcpinfo       *tcpinfo = (struct tcpinfo*)data;
  54
  55     col_set_str(pinfo->cinfo, COL_PROTOCOL, "FINGER");
  56
  57     if (pinfo->destport == FINGER_PORT) {
  58         is_query = true;
  59         col_set_str(pinfo->cinfo, COL_INFO, "Query");
  60     } else {
  61         is_query = false;
  62         col_set_str(pinfo->cinfo, COL_INFO, "Response");
  63     }
  64
  65     conversation = find_or_create_conversation(pinfo);
  66     finger_trans = (finger_transaction_t *)conversation_get_proto_data(conversation, proto_finger);
  67     if (finger_trans == NULL) {
  68         finger_trans = wmem_new0(wmem_file_scope(), finger_transaction_t);
  69         conversation_add_proto_data(conversation, proto_finger, finger_trans);
  70     }
  71
  72     len = tvb_reported_length(tvb);
  73     if (!PINFO_FD_VISITED(pinfo)) {
  74         if (pinfo->can_desegment) {
  75             if (is_query) {
  76                 if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {
  77                     pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
  78                     pinfo->desegment_offset = 0;
  79                     return -1;
  80                 } else {
  81                     finger_trans->req_frame = pinfo->num;
  82                     finger_trans->req_time = pinfo->abs_ts;
  83                 }
  84             } else if (!(tcpinfo && (IS_TH_FIN(tcpinfo->flags) || tcpinfo->is_reassembled))) {
  85                 /* If this is the FIN (or already desegmented, as with an out
  86                  * of order segment received after FIN) go ahead and dissect
  87                  * on the first pass.
  88                  */
  89                 pinfo->desegment_len = DESEGMENT_UNTIL_FIN;
  90                 pinfo->desegment_offset = 0;
  91                 return -1;
  92             }
  93         }
  94     } else if (is_query && (finger_trans->req_frame == 0)) {
  95         finger_trans->req_frame = pinfo->num;
  96         finger_trans->req_time = pinfo->abs_ts;
  97     }
  98
  99     if (!is_query && (finger_trans->rep_frame == 0)) {
 100         /* By comparing finger_trans->rep_frame to 0, if reassembly is turned
 101          * on, finger_trans->rep_frame will be assigned to the reassembled frame
 102          * number, and if reassembly is turned off, finger_trans->rep_frame will
 103          * be assigned to the first frame number of the response.  This seems
 104          * to match other protocols' behavior.  The alternative is:
 105          *      if (pinfo->num > finger_trans->rep_frame)
 106          * which will give us the same frame number either way.
 107          */
 108         finger_trans->rep_frame = pinfo->num;
 109     }
 110
 111     ti = proto_tree_add_protocol_format(tree, proto_finger, tvb, 0, -1,
 112         "FINGER: %s", is_query ? "Query" : "Response");
 113     finger_tree = proto_item_add_subtree(ti, ett_finger);
 114
 115     if (is_query) {
 116         expert_ti = proto_tree_add_item(finger_tree, hf_finger_query, tvb, 0, -1, ENC_ASCII);
 117         if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {
 118             /*
 119              * From RFC742, Send a single "command line", ending with <CRLF>.
 120              */
 121             expert_add_info(pinfo, expert_ti, &ei_finger_nocrlf);
 122         }
 123         if (tree && finger_trans->rep_frame) {
 124             ti = proto_tree_add_uint(finger_tree, hf_finger_response_in,
 125                 tvb, 0, 0, finger_trans->rep_frame);
 126             proto_item_set_generated(ti);
 127         }
 128     } else if (tree && finger_trans->rep_frame) {
 129         proto_tree_add_item(finger_tree, hf_finger_response, tvb, 0, -1, ENC_ASCII);
 130         if (finger_trans->req_frame) {
 131             nstime_t ns;
 132
 133             ti = proto_tree_add_uint(finger_tree, hf_finger_response_to,
 134                 tvb, 0, 0, finger_trans->req_frame);
 135             proto_item_set_generated(ti);
 136
 137             if (pinfo->num == finger_trans->rep_frame) {
 138                 nstime_delta(&ns, &pinfo->abs_ts, &finger_trans->req_time);
 139                 ti = proto_tree_add_time(finger_tree, hf_finger_response_time, tvb, 0, 0, &ns);
 140                 proto_item_set_generated(ti);
 141             }
 142         }
 143     }
 144
 145     return tvb_captured_length(tvb);
 146 }
 147
 148 void
 149 proto_register_finger(void)
 150 {
 151     expert_module_t *expert_finger;
 152
 153     static hf_register_info hf[] = {
 154         { &hf_finger_query,
 155             { "Query", "finger.query", FT_STRING, BASE_NONE, NULL, 0x0,
 156               NULL, HFILL }
 157         },
 158         { &hf_finger_response,
 159             { "Response", "finger.response", FT_STRING, BASE_NONE, NULL, 0x0,
 160               NULL, HFILL }
 161         },
 162         { &hf_finger_response_in,
 163             { "Response In", "finger.response_in", FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_RESPONSE),
 164               0x0, "The response to this FINGER query is in this frame",
 165               HFILL }
 166         },
 167         { &hf_finger_response_to,
 168             { "Request In", "finger.response_to", FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_REQUEST),
 169               0x0, "This is a response to the FINGER query in this frame",
 170               HFILL }
 171         },
 172         { &hf_finger_response_time,
 173             { "Response Time", "finger.response_time", FT_RELATIVE_TIME,
 174               BASE_NONE, NULL, 0x0,
 175               "The time between the Query and the Response", HFILL }
 176         }
 177     };
 178
 179     static int *ett[] = {
 180         &ett_finger
 181     };
 182
 183     static ei_register_info ei[] = {
 184         { &ei_finger_nocrlf,
 185             { "finger.nocrlf", PI_MALFORMED, PI_WARN, "Missing <CR><LF>", EXPFILL}
 186         }
 187     };
 188
 189     proto_finger = proto_register_protocol("finger", "FINGER", "finger");
 190     finger_handle = register_dissector("finger", dissect_finger, proto_finger);
 191     proto_register_field_array(proto_finger, hf, array_length(hf));
 192     proto_register_subtree_array(ett, array_length(ett));
 193     expert_finger = expert_register_protocol(proto_finger);
 194     expert_register_field_array(expert_finger, ei, array_length(ei));
 195 }
 196
 197 void
 198 proto_reg_handoff_finger(void)
 199 {
 200     dissector_add_uint_with_preference("tcp.port", FINGER_PORT, finger_handle);
 201 }
 202
 203 /*
 204  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 205  *
 206  * Local variables:
 207  * c-basic-offset: 4
 208  * tab-width: 8
 209  * indent-tabs-mode: nil
 210  * End:
 211  *
 212  * vi: set shiftwidth=4 tabstop=8 expandtab:
 213  * :indentSize=4:tabSize=8:noTabs=true:
 214  */
 215