diff options
| -rw-r--r-- | epan/dissectors/packet-fr.c | 138 |
1 files changed, 72 insertions, 66 deletions
diff --git a/epan/dissectors/packet-fr.c b/epan/dissectors/packet-fr.c index 1d32d16de2..3cf2ff5af3 100644 --- a/epan/dissectors/packet-fr.c +++ b/epan/dissectors/packet-fr.c @@ -556,79 +556,83 @@ dissect_fr_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, * See if, were we to treat the two octets after the DLCI as a Cisco * HDLC type, we have a dissector for it. */ - fr_type = tvb_get_ntohs(tvb, offset); - sub_dissector = dissector_get_uint_handle(chdlc_subdissector_table, - fr_type); - if (sub_dissector != NULL) { - /* We have a dissector, so assume it's Cisco encapsulation. */ - if (ti != NULL) { - /* Include the Cisco HDLC type in the top-level protocol - tree item. */ - proto_item_set_end(ti, tvb, offset+2); + if (tvb_bytes_exist(tvb, offset, 2)) { + fr_type = tvb_get_ntohs(tvb, offset); + sub_dissector = dissector_get_uint_handle(chdlc_subdissector_table, + fr_type); + if (sub_dissector != NULL) { + /* We have a dissector, so assume it's Cisco encapsulation. */ + if (ti != NULL) { + /* Include the Cisco HDLC type in the top-level protocol + tree item. */ + proto_item_set_end(ti, tvb, offset+2); + } + chdlctype(sub_dissector, fr_type, tvb, offset+2, pinfo, tree, fr_tree, + hf_fr_chdlctype); + return; } - chdlctype(sub_dissector, fr_type, tvb, offset+2, pinfo, tree, fr_tree, - hf_fr_chdlctype); - return; - } - /* - * We don't have a dissector; this might be an RFC 2427-encapsulated - * See if we have a dissector for the putative NLPID. - */ - nlpid_offset = offset; - control = tvb_get_guint8(tvb, nlpid_offset); - if (control == 0) { - /* Presumably a padding octet; the NLPID would be in the next octet. */ - nlpid_offset++; - control = tvb_get_guint8(tvb, nlpid_offset); - } - switch (control & 0x03) { - - case XDLC_S: /* - * Supervisory frame. - * We assume we're in extended mode, with 2-octet supervisory - * control fields. + * We don't have a dissector; this might be an RFC 2427-encapsulated + * See if we have a dissector for the putative NLPID. */ - nlpid_offset += 2; - break; + nlpid_offset = offset; + control = tvb_get_guint8(tvb, nlpid_offset); + if (control == 0) { + /* Presumably a padding octet; the NLPID would be in the next octet. */ + nlpid_offset++; + control = tvb_get_guint8(tvb, nlpid_offset); + } + switch (control & 0x03) { - case XDLC_U: - /* - * Unnumbered frame. - * - * XXX - one octet or 2 in extended mode? - */ - nlpid_offset++; - break; + case XDLC_S: + /* + * Supervisory frame. + * We assume we're in extended mode, with 2-octet supervisory + * control fields. + */ + nlpid_offset += 2; + break; - default: - /* - * Information frame. - * We assume we're in extended mode, with 2-octet supervisory - * control fields. - */ - nlpid_offset += 2; - break; - } - fr_nlpid = tvb_get_guint8(tvb, nlpid_offset); - sub_dissector = dissector_get_uint_handle(fr_osinl_subdissector_table, - fr_nlpid); - if (sub_dissector != NULL) - encap_is_frf_3_2 = TRUE; - else { - sub_dissector = dissector_get_uint_handle(osinl_incl_subdissector_table, - fr_nlpid); - if (sub_dissector != NULL) - encap_is_frf_3_2 = TRUE; - else { - if (fr_nlpid == NLPID_SNAP) + case XDLC_U: + /* + * Unnumbered frame. + * + * XXX - one octet or 2 in extended mode? + */ + nlpid_offset++; + break; + + default: + /* + * Information frame. + * We assume we're in extended mode, with 2-octet supervisory + * control fields. + */ + nlpid_offset += 2; + break; + } + if (tvb_bytes_exist(tvb, nlpid_offset, 1)) { + fr_nlpid = tvb_get_guint8(tvb, nlpid_offset); + sub_dissector = dissector_get_uint_handle(fr_osinl_subdissector_table, + fr_nlpid); + if (sub_dissector != NULL) encap_is_frf_3_2 = TRUE; else { - sub_dissector = dissector_get_uint_handle(fr_subdissector_table, + sub_dissector = dissector_get_uint_handle(osinl_incl_subdissector_table, fr_nlpid); if (sub_dissector != NULL) encap_is_frf_3_2 = TRUE; + else { + if (fr_nlpid == NLPID_SNAP) + encap_is_frf_3_2 = TRUE; + else { + sub_dissector = dissector_get_uint_handle(fr_subdissector_table, + fr_nlpid); + if (sub_dissector != NULL) + encap_is_frf_3_2 = TRUE; + } + } } } } @@ -658,14 +662,16 @@ dissect_fr_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, */ guint16 type_length; - next_tvb = tvb_new_subset_remaining(tvb, offset); - type_length = tvb_get_ntohs(tvb, offset + 12); - if (type_length <= IEEE_802_3_MAX_LEN || - dissector_get_uint_handle(ethertype_subdissector_table, type_length) != NULL) { + if (tvb_bytes_exist(tvb, offset + 12, 2) && + ((type_length = tvb_get_ntohs(tvb, offset + 12)) <= IEEE_802_3_MAX_LEN || + dissector_get_uint_handle(ethertype_subdissector_table, type_length) != NULL)) { /* It looks like a length or is a known Ethertype; dissect as raw Etheret */ + next_tvb = tvb_new_subset_remaining(tvb, offset); call_dissector(eth_withfcs_handle, next_tvb, pinfo, tree); + return; } else { /* It doesn't - just dissect it as data. */ + next_tvb = tvb_new_subset_remaining(tvb, offset); call_data_dissector(next_tvb, pinfo, tree); } } |