Move the request/response header helper routines to the epan directory.

svn path=/trunk/; revision=12129

1 files changed, 339 insertions, 0 deletions

diff --git a/epan/req_resp_hdrs.c b/epan/req_resp_hdrs.c
new file mode 100644
index 0000000000..1e6b99188e
--- /dev/null
+++ b/epan/req_resp_hdrs.c
@@ -0,0 +1,339 @@
+/* req_resp_hdrs.c
+ * Routines handling protocols with a request/response line, headers,
+ * a blank line, and an optional body.
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/strutil.h>
+#include <string.h>
+
+#include <epan/req_resp_hdrs.h>
+
+/*
+ * Optionally do reassembly of the request/response line, headers, and body.
+ */
+gboolean
+req_resp_hdrs_do_reassembly(tvbuff_t *tvb, packet_info *pinfo,
+    gboolean desegment_headers, gboolean desegment_body)
+{
+	gint		offset = 0;
+	gint		next_offset;
+	gint		next_offset_sav;
+	gint		length_remaining, reported_length_remaining;
+	int		linelen;
+	gchar		*header_val;
+	long int	content_length;
+	gboolean	content_length_found = FALSE;
+	gboolean	chunked_encoding = FALSE;
+
+	/*
+	 * Do header desegmentation if we've been told to.
+	 *
+	 * RFC 2616 defines HTTP messages as being either of the
+	 * Request or the Response type
+	 * (HTTP-message = Request | Response).
+	 * Request and Response are defined as:
+	 *     Request = Request-Line
+	 *         *(( general-header
+	 *         | request-header
+	 *         | entity-header ) CRLF)
+	 *         CRLF
+	 *         [ message-body ]
+	 *     Response = Status-Line
+	 *         *(( general-header
+	 *         | response-header
+	 *         | entity-header ) CRLF)
+	 *         CRLF
+	 *         [ message-body ]
+	 * that's why we can always assume two consecutive line
+	 * endings (we allow CR, LF, or CRLF, as some clients
+	 * or servers might not use a full CRLF) to mark the end
+	 * of the headers.  The worst thing that would happen
+	 * otherwise would be the packet not being desegmented
+	 * or being interpreted as only headers.
+	 *
+	 * RFC 2326 says RTSP works the same way; RFC 3261 says SIP
+	 * works the same way.
+	 */
+
+	/*
+	 * If header desegmentation is activated, check that all
+	 * headers are in this tvbuff (search for an empty line
+	 * marking end of headers) or request one more byte (we
+	 * don't know how many bytes we'll need, so we just ask
+	 * for one).
+	 */
+	if (desegment_headers && pinfo->can_desegment) {
+		next_offset = offset;
+		for (;;) {
+			next_offset_sav = next_offset;
+
+			length_remaining = tvb_length_remaining(tvb,
+			    next_offset);
+			reported_length_remaining =
+			    tvb_reported_length_remaining(tvb, next_offset);
+
+			/*
+			 * Request one more byte if there're no
+			 * bytes left in the reported data (if there're
+			 * bytes left in the reported data, but not in
+			 * the available data, requesting more bytes
+			 * won't help, as those bytes weren't captured).
+			 */
+			if (reported_length_remaining < 1) {
+				pinfo->desegment_offset = offset;
+				pinfo->desegment_len = 1;
+				return FALSE;
+			}
+
+			/*
+			 * Request one more byte if we cannot find a
+			 * header (i.e. a line end).
+			 */
+			linelen = tvb_find_line_end(tvb, next_offset,
+			    -1, &next_offset, TRUE);
+			if (linelen == -1 &&
+			    length_remaining >= reported_length_remaining) {
+				/*
+				 * Not enough data; ask for one more
+				 * byte.
+				 */
+				pinfo->desegment_offset = offset;
+				pinfo->desegment_len = 1;
+				return FALSE;
+			} else if (linelen == 0) {
+				/*
+				 * We found the end of the headers.
+				 */
+				break;
+			}
+
+			/*
+			 * Is this a Content-Length or Transfer-Encoding
+			 * header?  If not, it either means that we are in
+			 * a different header line, or that we are
+			 * at the end of the headers, or that there
+			 * isn't enough data; the two latter cases
+			 * have already been handled above.
+			 */
+			if (desegment_body) {
+				/*
+				 * Check if we've found Content-Length.
+				 */
+				if (tvb_strncaseeql(tvb, next_offset_sav,
+				    "Content-Length:", 15) == 0) {
+					header_val = tvb_get_string(tvb,
+					    next_offset_sav + 15,
+					    linelen - 15);
+					if (sscanf(header_val,
+					    "%li", &content_length)
+					    == 1)
+						content_length_found = TRUE;
+					g_free(header_val);
+				} else if (tvb_strncaseeql(tvb,
+					    next_offset_sav,
+					    "Transfer-Encoding:", 18) == 0) {
+					/*
+					 * Find out if this Transfer-Encoding is
+					 * chunked.  It should be, since there
+					 * really aren't any other types, but
+					 * RFC 2616 allows for them.
+					 */
+					gchar *p;
+					gint len;
+
+					header_val = tvb_get_string(tvb,
+					    next_offset_sav + 18, linelen - 18);
+					p = header_val;
+					len = strlen(header_val);
+					/* Skip white space */
+					while (p < header_val + len &&
+					    (*p == ' ' || *p == '\t'))
+						p++;
+					if (p <= header_val + len) {
+						if (strncasecmp(p, "chunked", 7)
+						    == 0) {
+							/*
+							 * Don't bother looking
+							 * for extensions;
+							 * since we don't
+							 * understand them,
+							 * they should be
+							 * ignored.
+							 */
+							chunked_encoding = TRUE;
+						}
+					}
+					g_free(header_val);
+				}
+			}
+		}
+	}
+
+	/*
+	 * The above loop ends when we reached the end of the headers, so
+	 * there should be content_length bytes after the 4 terminating bytes
+	 * and next_offset points to after the end of the headers.
+	 */
+	if (desegment_body) {
+		if (content_length_found) {
+			/* next_offset has been set to the end of the headers */
+			if (!tvb_bytes_exist(tvb, next_offset, content_length)) {
+				length_remaining = tvb_length_remaining(tvb,
+				    next_offset);
+				reported_length_remaining =
+				    tvb_reported_length_remaining(tvb, next_offset);
+				if (length_remaining < reported_length_remaining) {
+					/*
+					 * It's a waste of time asking for more
+					 * data, because that data wasn't captured.
+					 */
+					return TRUE;
+				}
+				if (length_remaining == -1)
+					length_remaining = 0;
+				pinfo->desegment_offset = offset;
+				pinfo->desegment_len =
+				    content_length - length_remaining;
+				return FALSE;
+			}
+		} else if (chunked_encoding) {
+			/*
+			 * This data is chunked, so we need to keep pulling
+			 * data until we reach the end of the stream, or a
+			 * zero sized chunk.
+			 *
+			 * XXX
+			 * This doesn't bother with trailing headers; I don't
+			 * think they are really used, and we'd have to use
+			 * is_http_request_or_reply() to determine if it was
+			 * a trailing header, or the start of a new response.
+			 */
+			gboolean done_chunking = FALSE;
+
+			while (!done_chunking) {
+				gint chunk_size = 0;
+				gint chunk_offset = 0;
+				gchar *chunk_string = NULL;
+				gchar *c = NULL;
+
+				length_remaining = tvb_length_remaining(tvb,
+				    next_offset);
+				reported_length_remaining =
+				    tvb_reported_length_remaining(tvb,
+				    next_offset);
+
+				if (reported_length_remaining < 1) {
+					pinfo->desegment_offset = offset;
+					pinfo->desegment_len = 1;
+					return FALSE;
+				}
+
+				linelen = tvb_find_line_end(tvb, next_offset,
+						-1, &chunk_offset, TRUE);
+
+				if (linelen == -1 &&
+				    length_remaining >=
+				    reported_length_remaining) {
+					 pinfo->desegment_offset = offset;
+					 pinfo->desegment_len = 2;
+					 return FALSE;
+				}
+				
+				/* We have a line with the chunk size in it.*/
+				chunk_string = tvb_get_string(tvb, next_offset,
+				    linelen);
+				c = chunk_string;
+
+				/*
+				 * We don't care about the extensions.
+				 */
+				if ((c = strchr(c, ';'))) {
+					*c = '\0';
+				}
+
+				if ((sscanf(chunk_string, "%x",
+				    &chunk_size) < 0) || chunk_size < 0) {
+					/* We couldn't get the chunk size,
+					 * so stop trying.
+					 */
+					return TRUE;
+				}
+
+				if (chunk_size == 0) {
+					/*
+					 * This is the last chunk.  Let's pull in the
+					 * trailing CRLF.
+					 */
+					linelen = tvb_find_line_end(tvb,
+					    chunk_offset, -1, &chunk_offset, TRUE);
+						
+					if (linelen == -1 &&
+					    length_remaining >=
+					    reported_length_remaining) {
+						pinfo->desegment_offset = offset;
+						pinfo->desegment_len = 1;
+						return FALSE;
+					}
+
+					pinfo->desegment_offset = chunk_offset;
+					pinfo->desegment_len = 0;
+					done_chunking = TRUE;
+				} else {
+					/* 
+					 * Skip to the next chunk if we
+					 * already have it 
+					 */
+					if (reported_length_remaining >
+					        chunk_size) {
+						
+						next_offset = chunk_offset 
+						    + chunk_size + 2;
+					} else {
+						/* 
+						 * Fetch this chunk, plus the
+						 * trailing CRLF.
+						 */ 
+						pinfo->desegment_offset = offset;
+						pinfo->desegment_len =
+						    chunk_size + 1 -
+						    reported_length_remaining;
+						return FALSE;
+					}
+				}
+
+			}
+		}
+
+	}
+
+	/*
+	 * No further desegmentation needed.
+	 */
+	return TRUE;
+}