WSLUA_METHOD Tvb_offset(lua_State* L) {
/* Returns the raw offset (from the beginning of the source Tvb) of a sub Tvb. */
Tvb tvb = checkTvb(L,1);
lua_pushnumber(L,tvb_raw_offset(tvb->ws_tvb));
WSLUA_RETURN(1); /* The raw offset of the Tvb. */
}
WSLUA_METHOD Tvb_offset(lua_State* L) {
/* Returns the raw offset (from the beginning of the source Tvb) of a sub Tvb. */
Tvb tvb = checkTvb(L,1);
if (!tvb) return 0;
if (tvb->expired) {
luaL_error(L,"expired tvb");
return 0;
}
lua_pushnumber(L,tvb_raw_offset(tvb->ws_tvb));
WSLUA_RETURN(1); /* The raw offset of the Tvb. */
}
/** Dissector for SoupBinTCP messages */
static void
dissect_soupbintcp_common(
tvbuff_t *tvb,
packet_info *pinfo,
proto_tree *tree)
{
struct conv_data *conv_data;
struct pdu_data *pdu_data;
const char *pkt_name;
const char *tmp_buf;
proto_item *ti;
proto_tree *soupbintcp_tree = NULL;
conversation_t *conv = NULL;
guint16 expected_len;
guint8 pkt_type;
gint offset = 0;
guint this_seq = 0, next_seq, key;
heur_dtbl_entry_t *hdtbl_entry;
/* Record the start of the packet to use as a sequence number key */
key = (guint)tvb_raw_offset(tvb);
/* Get the 16-bit big-endian SOUP packet length */
expected_len = tvb_get_ntohs(tvb, 0);
/* Get the 1-byte SOUP message type */
pkt_type = tvb_get_guint8(tvb, 2);
/* Since we use the packet name a few times, get and save that value */
pkt_name = val_to_str(pkt_type, pkt_type_val, "Unknown (%u)");
/* Set the protocol name in the summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "SoupBinTCP");
/* Set the packet name in the info column */
col_add_str(pinfo->cinfo, COL_INFO, pkt_name);
/* Sequence number tracking
*
* SOUP does not number packets from client to server (the server
* acknowledges all important messages, so the client should use
* the acks to figure out if the server received the message, and
* otherwise resend it).
*
* Packets from server to client are numbered, but it's implicit.
* The Login Accept packet contains the next sequence number that
* the server will send, and the client needs to count the
* Sequenced Data packets that it receives to know what their
* sequence numbers are.
*
* So, we grab the next sequence number from the Login Acceptance
* packet, and save it in a conversation_t we associate with the
* TCP session. Then, for each Sequenced Data packet we receive,
* the first time it's processed (when PINFO_FD_VISITED() is
* false), we write it into the PDU's frame's private data pointer
* and increment the saved sequence number (in the conversation_t).
*
* If the visited flag is true, then we've dissected this packet
* already, and so we can fetch the sequence number from the
* frame's private data area.
*
* In either case, if there's any problem, we report zero as the
* sequence number, and try to continue dissecting. */
/* If first dissection of Login Accept, save sequence number */
if (pkt_type == 'A' && !PINFO_FD_VISITED(pinfo)) {
tmp_buf = tvb_get_string_enc(wmem_packet_scope(), tvb, 13, 20, ENC_ASCII);
next_seq = atoi(tmp_buf);
/* Create new conversation for this session */
conv = conversation_new(pinfo->num,
&pinfo->src,
&pinfo->dst,
pinfo->ptype,
pinfo->srcport,
pinfo->destport,
0);
/* Store starting sequence number for session's packets */
conv_data = (struct conv_data *)wmem_alloc(wmem_file_scope(), sizeof(struct conv_data));
conv_data->next_seq = next_seq;
conversation_add_proto_data(conv, proto_soupbintcp, conv_data);
}
/* Handle sequence numbering for a Sequenced Data packet */
if (pkt_type == 'S') {
if (!PINFO_FD_VISITED(pinfo)) {
/* Get next expected sequence number from conversation */
conv = find_conversation(pinfo->num,
&pinfo->src,
&pinfo->dst,
pinfo->ptype,
pinfo->srcport,
pinfo->destport,
0);
if (!conv) {
this_seq = 0;
} else {
conv_data = (struct conv_data *)conversation_get_proto_data(conv,
proto_soupbintcp);
if (conv_data) {
this_seq = conv_data->next_seq++;
} else {
this_seq = 0;
}
pdu_data = (struct pdu_data *)wmem_alloc(
wmem_file_scope(),
sizeof(struct pdu_data));
pdu_data->seq_num = this_seq;
p_add_proto_data(wmem_file_scope(), pinfo, proto_soupbintcp, key, pdu_data);
}
} else {
pdu_data = (struct pdu_data *)p_get_proto_data(wmem_file_scope(), pinfo, proto_soupbintcp, key);
if (pdu_data) {
this_seq = pdu_data->seq_num;
} else {
this_seq = 0;
}
}
col_append_fstr(pinfo->cinfo, COL_INFO, ", SeqNum = %u", this_seq);
}
if (tree) {
/* Create sub-tree for SoupBinTCP details */
ti = proto_tree_add_item(tree,
proto_soupbintcp,
tvb, 0, -1, ENC_NA);
soupbintcp_tree = proto_item_add_subtree(ti, ett_soupbintcp);
/* Append the packet name to the sub-tree item */
proto_item_append_text(ti, ", %s", pkt_name);
/* Length */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_packet_length,
tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
/* Type */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_packet_type,
tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
switch (pkt_type) {
case '+': /* Debug Message */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_text,
tvb, offset, expected_len - 1, ENC_ASCII|ENC_NA);
break;
case 'A': /* Login Accept */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_session,
tvb, offset, 10, ENC_ASCII|ENC_NA);
offset += 10;
tmp_buf = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, 20, ENC_ASCII);
proto_tree_add_string_format_value(soupbintcp_tree,
hf_soupbintcp_next_seq_num,
tvb, offset, 20,
"X", "%d", atoi(tmp_buf));
break;
case 'J': /* Login Reject */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_reject_code,
tvb, offset, 1, ENC_BIG_ENDIAN);
break;
case 'U': /* Unsequenced Data */
/* Display handled by sub-dissector */
break;
case 'S': /* Sequenced Data */
proto_item_append_text(ti, ", SeqNum=%u", this_seq);
proto_tree_add_string_format_value(soupbintcp_tree,
hf_soupbintcp_seq_num,
tvb, offset, 0,
"X",
"%u (Calculated)",
this_seq);
/* Display handled by sub-dissector */
break;
case 'L': /* Login Request */
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_username,
tvb, offset, 6, ENC_ASCII|ENC_NA);
offset += 6;
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_password,
tvb, offset, 10, ENC_ASCII|ENC_NA);
offset += 10;
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_session,
tvb, offset, 10, ENC_ASCII|ENC_NA);
offset += 10;
tmp_buf = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, 20, ENC_ASCII);
proto_tree_add_string_format_value(soupbintcp_tree,
hf_soupbintcp_req_seq_num,
tvb, offset, 20,
"X", "%d", atoi(tmp_buf));
break;
case 'H': /* Server Heartbeat */
break;
case 'O': /* Logout Request */
break;
case 'R': /* Client Heartbeat */
break;
case 'Z': /* End of Session */
break;
default:
/* Unknown */
proto_tree_add_item(tree,
hf_soupbintcp_message,
tvb, offset, -1, ENC_NA);
break;
}
}
/* Call sub-dissector for encapsulated data */
if (pkt_type == 'S' || pkt_type == 'U') {
tvbuff_t *sub_tvb;
/* Sub-dissector tvb starts at 3 (length (2) + pkt_type (1)) */
sub_tvb = tvb_new_subset_remaining(tvb, 3);
#if 0 /* XXX: It's not valid for a soupbintcp subdissector to call */
/* conversation_set_dissector() since the conversation is really */
/* a TCP conversation. (A 'soupbintcp' port type would need to */
/* be defined to be able to use conversation_set_dissector()). */
/* In addition, no current soupbintcp subdissector calls */
/* conversation_set_dissector(). */
/* If this packet is part of a conversation, call dissector
* for the conversation if available */
if (try_conversation_dissector(&pinfo->dst, &pinfo->src, pinfo->ptype,
pinfo->srcport, pinfo->destport,
sub_tvb, pinfo, tree, NULL)) {
return;
}
#endif
/* Otherwise, try heuristic dissectors */
if (dissector_try_heuristic(heur_subdissector_list,
sub_tvb,
pinfo,
tree,
&hdtbl_entry,
NULL)) {
return;
}
/* Otherwise, give up, and just print the bytes in hex */
if (tree) {
proto_tree_add_item(soupbintcp_tree,
hf_soupbintcp_message,
sub_tvb, 0, -1,
ENC_NA);
}
}
}
