diff options
Diffstat (limited to 'epan/dissectors/packet-jxta.c')
| -rw-r--r-- | epan/dissectors/packet-jxta.c | 109 |
1 files changed, 106 insertions, 3 deletions
diff --git a/epan/dissectors/packet-jxta.c b/epan/dissectors/packet-jxta.c index c4baf749b6..8b0e8abb47 100644 --- a/epan/dissectors/packet-jxta.c +++ b/epan/dissectors/packet-jxta.c @@ -338,6 +338,9 @@ static gboolean dissect_jxta_UDP_heur(tvbuff_t * tvb, packet_info * pinfo, proto * traffic not sent to a known dissector and not claimed by * a heuristic dissector called before us! */ + int save_desegment_offset; + guint32 save_desegment_len; + int ret; if (!gUDP_HEUR) return FALSE; @@ -346,7 +349,33 @@ static gboolean dissect_jxta_UDP_heur(tvbuff_t * tvb, packet_info * pinfo, proto return FALSE; } - return (dissect_jxta_udp(tvb, pinfo, tree) > 0) ? TRUE : FALSE; + save_desegment_offset = pinfo->desegment_offset; + save_desegment_len = pinfo->desegment_len; + ret = dissect_jxta_udp(tvb, pinfo, tree); + if (ret < 0) { + /* + * UDP is not a packet stream protocol, so the UDP dissector + * should not, and will not, do the sort of dissection help + * that the TCP dissector will. If JXTA messages don't + * start and end on UDP packet boundaries, the JXTA dissector + * will have to do its own byte stream reassembly. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else if (ret == 0) { + /* + * A clear rejection. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else { + /* + * A clear acceptance. + */ + return TRUE; + } } /** @@ -363,11 +392,50 @@ static gboolean dissect_jxta_TCP_heur(tvbuff_t * tvb, packet_info * pinfo, proto * traffic not sent to a known dissector and not claimed by * a heuristic dissector called before us! */ + int save_desegment_offset; + guint32 save_desegment_len; + int ret; if (!gTCP_HEUR) return FALSE; - return (dissect_jxta_stream(tvb, pinfo, tree) > 0) ? TRUE : FALSE; + save_desegment_offset = pinfo->desegment_offset; + save_desegment_len = pinfo->desegment_len; + ret = dissect_jxta_stream(tvb, pinfo, tree); + if (ret <= 0) { + /* + * A heuristic dissector for a TCP-based protocol can reject + * a packet, or it can request that more data be provided. + * It must not attempt to do both, as the notion of doing both + * is nonsensical - if the packet isn't considered a packet + * for the dissector's protocol, that dissector won't be + * dissecting it no matter *how* much more data is added. + * + * Therefore, we treat a negative return from + * dissect_jxta_stream() as a rejection. + * + * If that's not desired - i.e., if we should keep trying to get + * more data, in the hopes that we'll eventually be able to + * determine whether the packet is a JXTA packet or not - we + * should, in this case, leave pinfo->desegment_offset and + * pinfo->desegment_len alone, and return TRUE, *NOT* FALSE. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else if (ret == 0) { + /* + * A clear rejection. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else { + /* + * A clear acceptance. + */ + return TRUE; + } } /** @@ -384,11 +452,46 @@ static gboolean dissect_jxta_SCTP_heur(tvbuff_t * tvb, packet_info * pinfo, prot * traffic not sent to a known dissector and not claimed by * a heuristic dissector called before us! */ + int save_desegment_offset; + guint32 save_desegment_len; + int ret; if (!gSCTP_HEUR) return FALSE; - return (dissect_jxta_stream(tvb, pinfo, tree) > 0) ? TRUE : FALSE; + save_desegment_offset = pinfo->desegment_offset; + save_desegment_len = pinfo->desegment_len; + ret = dissect_jxta_stream(tvb, pinfo, tree); + if (ret < 0) { + /* + * SCTP is not a byte stream protocol, so the SCTP dissector + * should not, and will not, do the sort of dissection help + * that the SCTP dissector will. If JXTA messages don't + * start and end on SCTP packet boundaries, the JXTA dissector + * will have to do its own byte stream reassembly. + * + * The SCTP dissector currently won't do reassembly. If that + * causes a problem for the JXTA dissector, the correct fix + * is to implement reassembly in the SCTP dissector, so *all* + * dissectors for protocols running atop SCTP can benefit from + * it. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else if (ret == 0) { + /* + * A clear rejection. + */ + pinfo->desegment_offset = save_desegment_offset; + pinfo->desegment_len = save_desegment_len; + return FALSE; + } else { + /* + * A clear acceptance. + */ + return TRUE; + } } /** |