diff options
| -rw-r--r-- | packet-rtsp.c | 234 |
1 files changed, 195 insertions, 39 deletions
diff --git a/packet-rtsp.c b/packet-rtsp.c index 4f0c09b879..c889203e81 100644 --- a/packet-rtsp.c +++ b/packet-rtsp.c @@ -4,7 +4,7 @@ * Jason Lango <jal@netapp.com> * Liberally copied from packet-http.c, by Guy Harris <guy@alum.mit.edu> * - * $Id: packet-rtsp.c,v 1.28 2000/11/30 02:06:30 guy Exp $ + * $Id: packet-rtsp.c,v 1.29 2000/12/02 06:05:29 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs <gerald@zing.org> @@ -36,6 +36,7 @@ #include <string.h> #include <ctype.h> +#include <stdlib.h> #include <glib.h> #include "packet.h" @@ -53,6 +54,13 @@ static int hf_rtsp_status = -1; #define TCP_PORT_RTSP 554 +/* + * Takes an array of bytes, assumed to contain a null-terminated + * string, as an argument, and returns the length of the string - + * i.e., the size of the array, minus 1 for the null terminator. + */ +#define STRLEN_CONST(str) (sizeof (str) - 1) + static void process_rtsp_request(tvbuff_t *tvb, int offset, const u_char *data, int linelen, proto_tree *tree); @@ -102,33 +110,30 @@ is_rtsp_request_or_reply(const u_char *line, int linelen) return NOT_RTSP; } +static const char rtsp_content_type[] = "Content-Type:"; + static int is_content_sdp(const u_char *line, int linelen) { - const char *hdr = "Content-Type:"; - size_t hdrlen = strlen(hdr); - const char *type = "application/sdp"; - size_t typelen = strlen(type); + static const char type[] = "application/sdp"; + size_t typelen = STRLEN_CONST(type); - if (linelen < hdrlen || strncasecmp(hdr, line, hdrlen)) - return 0; - - line += hdrlen; - linelen -= hdrlen; + line += STRLEN_CONST(rtsp_content_type); + linelen -= STRLEN_CONST(rtsp_content_type); while (linelen > 0 && (*line == ' ' || *line == '\t')) { line++; linelen--; } if (linelen < typelen || strncasecmp(type, line, typelen)) - return 0; + return FALSE; line += typelen; linelen -= typelen; if (linelen > 0 && !isspace(*line)) - return 0; + return FALSE; - return 1; + return TRUE; } static const char rtsp_transport[] = "Transport:"; @@ -137,31 +142,37 @@ static const char rtsp_cps[] = "client_port="; static const char rtsp_rtp[] = "rtp/avp"; static void -rtsp_create_conversation(const u_char *trans_begin, const u_char *trans_end) +rtsp_create_conversation(const u_char *line_begin, int line_len) { conversation_t *conv; - u_char tbuf[256]; + u_char buf[256]; u_char *tmp; int c_data_port, c_mon_port; int s_data_port, s_mon_port; - strncpy(tbuf, trans_begin, trans_end - trans_begin); - tbuf[sizeof(tbuf)-1] = 0; + if (line_len > sizeof(buf) - 1) { + /* + * Don't overflow the buffer. + */ + line_len = sizeof(buf) - 1; + } + memcpy(buf, line_begin, line_len); + buf[line_len] = '\0'; - tmp = tbuf + strlen(rtsp_transport); + tmp = buf + STRLEN_CONST(rtsp_transport); while (*tmp && isspace(*tmp)) tmp++; if (strncasecmp(tmp, rtsp_rtp, strlen(rtsp_rtp)) != 0) - return; + return; /* we don't know this transport */ c_data_port = c_mon_port = 0; s_data_port = s_mon_port = 0; - if ((tmp = strstr(tbuf, rtsp_sps))) { + if ((tmp = strstr(buf, rtsp_sps))) { tmp += strlen(rtsp_sps); if (sscanf(tmp, "%u-%u", &s_data_port, &s_mon_port) < 1) g_warning("rtsp: failed to parse server_port"); } - if ((tmp = strstr(tbuf, rtsp_cps))) { + if ((tmp = strstr(buf, rtsp_cps))) { tmp += strlen(rtsp_cps); if (sscanf(tmp, "%u-%u", &c_data_port, &c_mon_port) < 1) g_warning("rtsp: failed to parse client_port"); @@ -181,24 +192,54 @@ rtsp_create_conversation(const u_char *trans_begin, const u_char *trans_end) conversation_set_dissector(conv, dissect_rtcp); } -static void -dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +static const char rtsp_content_length[] = "Content-Length:"; + +static int +rtsp_get_content_length(const u_char *line_begin, int line_len) +{ + u_char buf[256]; + u_char *tmp; + long content_length; + char *p; + u_char *up; + + if (line_len > sizeof(buf) - 1) { + /* + * Don't overflow the buffer. + */ + line_len = sizeof(buf) - 1; + } + memcpy(buf, line_begin, line_len); + buf[line_len] = '\0'; + + tmp = buf + STRLEN_CONST(rtsp_content_length); + while (*tmp && isspace(*tmp)) + tmp++; + content_length = strtol(tmp, &p, 10); + up = p; + if (up == tmp || (*up != '\0' && !isspace(*up))) + return -1; /* not a valid number */ + return content_length; +} + +static int +dissect_rtspmessage(tvbuff_t *tvb, int offset, packet_info *pinfo, + proto_tree *tree) { proto_tree *rtsp_tree; proto_item *ti = NULL; - gint offset = 0; const u_char *line; gint next_offset; const u_char *linep, *lineend; - int linelen; + int orig_offset, linelen; u_char c; + gboolean is_mime_header; int is_sdp = FALSE; int datalen; + int content_length; + int reported_datalen; - CHECK_DISPLAY_AS_DATA(proto_rtsp, tvb, pinfo, tree); - - pinfo->current_proto = "RTSP"; - + orig_offset = offset; rtsp_tree = NULL; if (tree) { ti = proto_tree_add_item(tree, proto_rtsp, tvb, offset, @@ -206,8 +247,6 @@ dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) rtsp_tree = proto_item_add_subtree(ti, ett_rtsp); } - if (check_col(pinfo->fd, COL_PROTOCOL)) - col_set_str(pinfo->fd, COL_PROTOCOL, "RTSP"); if (check_col(pinfo->fd, COL_INFO)) { /* * Put the first line from the buffer into the summary @@ -232,10 +271,20 @@ dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) } /* + * We haven't yet seen a Content-Length header. + */ + content_length = -1; + + /* * Process the packet data, a line at a time. */ while (tvb_offset_exists(tvb, offset)) { /* + * We haven't yet concluded that this is a MIME header. + */ + is_mime_header = FALSE; + + /* * Find the end of the line. */ linelen = tvb_find_line_end(tvb, offset, -1, &next_offset); @@ -314,8 +363,7 @@ dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) * This ends the token; we consider * this to be a MIME header. */ - if (is_content_sdp(line, linelen)) - is_sdp = TRUE; + is_mime_header = TRUE; goto is_rtsp; } } @@ -336,14 +384,73 @@ dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) next_offset - offset, "%s", tvb_format_text(tvb, offset, next_offset - offset)); } - if (linelen > strlen(rtsp_transport) && - strncasecmp(line, rtsp_transport, - strlen(rtsp_transport)) == 0) - rtsp_create_conversation(line, line + linelen); + if (is_mime_header) { + /* + * Process some MIME headers specially. + */ +#define MIME_HDR_MATCHES(header) \ + (linelen > STRLEN_CONST(header) && \ + strncasecmp(line, (header), STRLEN_CONST(header)) == 0) + + if (MIME_HDR_MATCHES(rtsp_transport)) { + /* + * Based on the port numbers specified + * in the Transport: header, set up + * a conversation that will be dissected + * with the appropriate dissector. + */ + rtsp_create_conversation(line, linelen); + } else if (MIME_HDR_MATCHES(rtsp_content_type)) { + /* + * If the Content-Type: header says this + * is SDP, dissect the payload as SDP. + */ + if (is_content_sdp(line, linelen)) + is_sdp = TRUE; + } else if (MIME_HDR_MATCHES(rtsp_content_length)) { + /* + * Only the amount specified by the + * Content-Length: header should be treated + * as payload. + */ + content_length = rtsp_get_content_length(line, + linelen); + } + } offset = next_offset; } + /* + * If a content length was supplied, the amount of data to be + * processed as RTSP payload is the minimum of the content + * length and the amount of data remaining in the frame. + * + * If no content length was supplied, the amount of data to be + * processed is the amount of data remaining in the frame. + */ datalen = tvb_length_remaining(tvb, offset); + if (content_length != -1) { + if (datalen > content_length) + datalen = content_length; + + /* + * XXX - for now, if the content length is greater + * than the amount of data left in this frame (not + * the amount of *captured* data left in the frame + * minus the current offset, but the amount of *actual* + * data that was reported to be in the frame minus + * the current offset), limit it to the amount + * of data left in this frame. + * + * If we ever handle data that crosses frame + * boundaries, we'll need to remember the actual + * content length. + */ + reported_datalen = tvb_reported_length(tvb) - offset; + if (content_length > reported_datalen) + content_length = reported_datalen; + } + if (datalen > 0) { /* * There's stuff left over; process it. @@ -359,16 +466,37 @@ dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) proto_item_set_len(ti, offset); /* - * Now creat a tvbuff for the SDP stuff and + * Now create a tvbuff for the SDP stuff and * dissect it. + * + * The amount of data to be processed that's + * available in the tvbuff is "datalen", which + * is the minimum of the amount of data left in + * the tvbuff and any specified content length. + * + * The amount of data to be processed that's in + * this frame, regardless of whether it was + * captured or not, is "content_length", + * which, if no content length was specified, + * is -1, i.e. "to the end of the frame. */ - new_tvb = tvb_new_subset(tvb, offset, -1, -1); + new_tvb = tvb_new_subset(tvb, offset, datalen, + content_length); call_dissector(sdp_handle, new_tvb, pinfo, tree); } else { proto_tree_add_text(rtsp_tree, tvb, offset, datalen, "Data (%d bytes)", datalen); } + + /* + * We've processed "datalen" bytes worth of data + * (which may be no data at all); advance the + * offset past whatever data we've processed, so they + * don't process it. + */ + offset += datalen; } + return offset - orig_offset; } static void @@ -440,6 +568,34 @@ process_rtsp_reply(tvbuff_t *tvb, int offset, const u_char *data, status - status_start, status_i); } +static void +dissect_rtsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + int offset = 0; + int len; + + CHECK_DISPLAY_AS_DATA(proto_rtsp, tvb, pinfo, tree); + + pinfo->current_proto = "RTSP"; + + if (check_col(pinfo->fd, COL_PROTOCOL)) + col_set_str(pinfo->fd, COL_PROTOCOL, "RTSP"); + + while (tvb_offset_exists(tvb, offset)) { + len = dissect_rtspmessage(tvb, offset, pinfo, tree); + if (len == -1) + break; + offset += len; + + /* + * OK, we've set the Protocol and Info columns for the + * first RTSP message; make the columns non-writable, + * so that we don't change it for subsequent RTSP messages. + */ + col_set_writable(pinfo->fd, FALSE); + } +} + void proto_register_rtsp(void) { |