epan/req_resp_hdrs.h

   1 /** @file
   2  * Declarations of routines handling protocols with a request/response line,
   3  * headers, a blank line, and an optional body.
   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 #ifndef __REQ_RESP_HDRS_H__
  13 #define __REQ_RESP_HDRS_H__
  14
  15 #include "ws_symbol_export.h"
  16 #include "wsutil/strtoi.h"
  17
  18 /**
  19  * Optionally do reassembly of the request/response line, headers, and body.
  20  *
  21  *  @param tvb  The buffer.
  22  *  @param offset   The offset in the buffer to begin inspection.
  23  *  @param pinfo    Packet info from the parent protocol.
  24  *  @param desegment_headers    Do desegmentation on headers.
  25  *  @param desegment_body   Do desegmentation on body.
  26  *  @param desegment_until_fin  When desegment_body is enabled and no
  27  *  Content-Length header is found, assume that all data following the headers
  28  *  are part of the body.
  29  *  @param[in,out] last_chunk_offset  For the chunked Transfer-Encoding,
  30  *  the offset (relative to the initial tvb offset) of the last chunk size
  31  *  found.  The result can be fed back into a future call in order to skip
  32  *  to a later chunk and reduce processing from O(N^2) to O(N).  Use 0 for
  33  *  the initial call.  Only set when chunked TE is found.  May be NULL.
  34  *  @param streaming_subdissector_table   For searching a streaming reassembly
  35  *  mode supported subdissector on it by the content-type header value.
  36  *  @param[out] streaming_chunk_handle   Only set when this is the beginning of
  37  *  a chunk stream. (There is 'Transfer-Encoding: chunked' header and a
  38  *  streaming reassembly mode supported subdissector is found according to
  39  *  Content-Type header)
  40  *  @return true if desegmentation is complete otherwise false
  41  */
  42 WS_DLL_PUBLIC bool
  43 req_resp_hdrs_do_reassembly(tvbuff_t *tvb, const  int offset, packet_info *pinfo,
  44     const bool desegment_headers, const bool desegment_body,
  45     bool desegment_until_fin, int *last_chunk_offset,
  46         dissector_table_t streaming_subdissector_table, dissector_handle_t *streaming_chunk_handle);
  47
  48 /** Check whether the first line is the beginning of a chunk. */
  49 static inline bool
  50 starts_with_chunk_size(tvbuff_t* tvb, const int offset, packet_info* pinfo)
  51 {
  52         unsigned chunk_size = 0;
  53         int linelen = tvb_find_line_end(tvb, offset, tvb_reported_length_remaining(tvb, offset), NULL, true);
  54
  55         if (linelen < 0)
  56                 return false;
  57
  58         char* chunk_string = tvb_get_string_enc(pinfo->pool, tvb, offset, linelen, ENC_ASCII);
  59         char* c = chunk_string;
  60
  61         /* ignore extensions, including optional BWS ("bad whitespace")
  62          * in the grammar for historical reasons, see RFC 9112 7.1.1.
  63          */
  64         if ((c = strpbrk(c, "; \t"))) {
  65                 *c = '\0';
  66         }
  67
  68         if (!ws_hexstrtou32(chunk_string, NULL, &chunk_size)) {
  69                 return false; /* can not get chunk size*/
  70         } else if (chunk_size > (1U << 31)) {
  71                 return false; /* chunk size is unreasonable */
  72         }
  73         return true;
  74 }
  75
  76 #endif