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|
/* packet-pop.c
* Routines for pop packet dissection
* RFC 1939
* Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Copied from packet-tftp.c
*
* 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 <stdio.h>
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/strutil.h>
#include <epan/conversation.h>
#include <epan/prefs.h>
#include <epan/reassemble.h>
#include "packet-ssl.h"
static int proto_pop = -1;
static int hf_pop_response = -1;
static int hf_pop_response_indicator = -1;
static int hf_pop_response_description = -1;
static int hf_pop_response_data = -1;
static int hf_pop_request = -1;
static int hf_pop_request_command = -1;
static int hf_pop_request_parameter = -1;
static int hf_pop_request_data = -1;
static int hf_pop_data_fragments = -1;
static int hf_pop_data_fragment = -1;
static int hf_pop_data_fragment_overlap = -1;
static int hf_pop_data_fragment_overlap_conflicts = -1;
static int hf_pop_data_fragment_multiple_tails = -1;
static int hf_pop_data_fragment_too_long_fragment = -1;
static int hf_pop_data_fragment_error = -1;
static int hf_pop_data_reassembled_in = -1;
static gint ett_pop = -1;
static gint ett_pop_reqresp = -1;
static gint ett_pop_data_fragment = -1;
static gint ett_pop_data_fragments = -1;
static dissector_handle_t data_handle;
static dissector_handle_t imf_handle = NULL;
#define TCP_PORT_POP 110
#define TCP_PORT_SSL_POP 995
/* desegmentation of POP command and response lines */
static gboolean pop_data_desegment = TRUE;
static GHashTable *pop_data_segment_table = NULL;
static GHashTable *pop_data_reassembled_table = NULL;
static const fragment_items pop_data_frag_items = {
/* Fragment subtrees */
&ett_pop_data_fragment,
&ett_pop_data_fragments,
/* Fragment fields */
&hf_pop_data_fragments,
&hf_pop_data_fragment,
&hf_pop_data_fragment_overlap,
&hf_pop_data_fragment_overlap_conflicts,
&hf_pop_data_fragment_multiple_tails,
&hf_pop_data_fragment_too_long_fragment,
&hf_pop_data_fragment_error,
/* Reassembled in field */
&hf_pop_data_reassembled_in,
/* Tag */
"DATA fragments"
};
struct pop_proto_data {
guint16 conversation_id;
gboolean more_frags;
};
struct pop_data_val {
gboolean msg_request;
guint32 msg_read_len; /* Length of RETR message read so far */
guint32 msg_tot_len; /* Total length of RETR message */
};
static gboolean response_is_continuation(const guchar *data);
static void
dissect_pop(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
struct pop_proto_data *frame_data;
gboolean is_request;
gboolean is_continuation;
proto_tree *pop_tree, *reqresp_tree;
proto_item *ti;
gint offset = 0;
const guchar *line;
gint next_offset;
int linelen;
int tokenlen;
const guchar *next_token;
fragment_data *frag_msg = NULL;
tvbuff_t *next_tvb = NULL;
conversation_t *conversation = NULL;
struct pop_data_val *data_val = NULL;
gint length_remaining;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "POP");
/*
* Find the end of the first line.
*
* Note that "tvb_find_line_end()" will return a value that is
* not longer than what's in the buffer, so the "tvb_get_ptr()"
* call won't throw an exception.
*/
linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
line = tvb_get_ptr(tvb, offset, linelen);
if (pinfo->match_port == pinfo->destport) {
is_request = TRUE;
is_continuation = FALSE;
} else {
is_request = FALSE;
is_continuation = response_is_continuation(line);
}
frame_data = p_get_proto_data(pinfo->fd, proto_pop);
if (!frame_data) {
conversation = find_conversation(pinfo->fd->num,
&pinfo->src, &pinfo->dst,
pinfo->ptype,
pinfo->srcport, pinfo->destport, 0);
if (conversation == NULL) { /* No conversation, create one */
conversation = conversation_new(pinfo->fd->num,
&pinfo->src, &pinfo->dst, pinfo->ptype,
pinfo->srcport, pinfo->destport, 0);
}
data_val = conversation_get_proto_data(conversation, proto_pop);
if (!data_val) {
/*
* No - create one and attach it.
*/
data_val = se_alloc(sizeof(struct pop_data_val));
data_val->msg_request = FALSE;
data_val->msg_read_len = 0;
data_val->msg_tot_len = 0;
conversation_add_proto_data(conversation, proto_pop, data_val);
}
}
if (check_col(pinfo->cinfo, COL_INFO)) {
/*
* Put the first line from the buffer into the summary
* if it's a POP request or reply (but leave out the
* line terminator).
* Otherwise, just call it a continuation.
*/
if (is_continuation) {
length_remaining = tvb_length_remaining(tvb, offset);
col_set_str(pinfo->cinfo, COL_INFO, "S: DATA fragment");
col_append_fstr(pinfo->cinfo, COL_INFO, ", %d byte%s",
length_remaining,
plurality (length_remaining, "", "s"));
}
else
col_add_fstr(pinfo->cinfo, COL_INFO, "%s: %s",
is_request ? "C" : "S",
format_text(line, linelen));
}
if (tree) {
ti = proto_tree_add_item(tree, proto_pop, tvb, offset, -1,
FALSE);
pop_tree = proto_item_add_subtree(ti, ett_pop);
if (is_continuation) {
if(pop_data_desegment) {
if(!frame_data) {
data_val->msg_read_len += tvb_length(tvb);
frame_data = se_alloc(sizeof(struct pop_proto_data));
frame_data->conversation_id = conversation->index;
frame_data->more_frags = data_val->msg_read_len < data_val->msg_tot_len;
p_add_proto_data(pinfo->fd, proto_pop, frame_data);
}
frag_msg = fragment_add_seq_next (tvb, 0, pinfo,
frame_data->conversation_id,
pop_data_segment_table,
pop_data_reassembled_table,
tvb_length(tvb),
frame_data->more_frags);
next_tvb = process_reassembled_data (tvb, offset, pinfo,
"Reassembled DATA",
frag_msg, &pop_data_frag_items,
NULL, pop_tree);
if(next_tvb) {
if(imf_handle)
call_dissector(imf_handle, next_tvb, pinfo, tree);
if(data_val) {
/* we have read everything - reset */
data_val->msg_read_len = 0;
data_val->msg_tot_len = 0;
}
pinfo->fragmented = FALSE;
} else {
pinfo->fragmented = TRUE;
}
} else {
/*
* Put the whole packet into the tree as data.
*/
call_dissector(data_handle,tvb, pinfo, pop_tree);
}
return;
}
/*
* Put the line into the protocol tree.
*/
ti = proto_tree_add_string_format(pop_tree,
(is_request) ?
hf_pop_request :
hf_pop_response,
tvb, offset,
next_offset - offset,
"", "%s",
tvb_format_text(tvb, offset, next_offset - offset));
reqresp_tree = proto_item_add_subtree(ti, ett_pop_reqresp);
/*
* Extract the first token, and, if there is a first
* token, add it as the request or reply code.
*/
tokenlen = get_token_len(line, line + linelen, &next_token);
if (tokenlen != 0) {
proto_tree_add_item(reqresp_tree,
(is_request) ?
hf_pop_request_command :
hf_pop_response_indicator,
tvb, offset, tokenlen, FALSE);
if(is_request) {
/* see if this is RETR or TOP command */
if((g_ascii_strncasecmp(line, "RETR", 4) == 0) ||
(g_ascii_strncasecmp(line, "TOP", 3) == 0))
/* the next response will tell us how many bytes */
data_val->msg_request = TRUE;
} else {
if(data_val->msg_request) {
/* this is a response to a RETR or TOP command */
if(g_ascii_strncasecmp(line, "+OK ", 4) == 0) {
/* the message will be sent - work out how many bytes */
data_val->msg_read_len = 0;
data_val->msg_tot_len = atoi(line + 4);
}
data_val->msg_request = FALSE;
}
}
offset += (gint) (next_token - line);
linelen -= (int) (next_token - line);
line = next_token;
}
/*
* Add the rest of the first line as request or
* reply param/description.
*/
if (linelen != 0) {
proto_tree_add_item(reqresp_tree,
(is_request) ?
hf_pop_request_parameter :
hf_pop_response_description,
tvb, offset, linelen, FALSE);
}
offset = next_offset;
/*
* Show the rest of the request or response as text,
* a line at a time.
*/
while (tvb_offset_exists(tvb, offset)) {
/*
* Find the end of the line.
*/
linelen = tvb_find_line_end(tvb, offset, -1,
&next_offset, FALSE);
/*
* Put this line.
*/
proto_tree_add_string_format(pop_tree,
(is_request) ?
hf_pop_request_data :
hf_pop_response_data,
tvb, offset,
next_offset - offset,
"", "%s",
tvb_format_text(tvb, offset, next_offset - offset));
offset = next_offset;
}
}
}
static gboolean response_is_continuation(const guchar *data)
{
if (strncmp(data, "+OK", strlen("+OK")) == 0)
return FALSE;
if (strncmp(data, "-ERR", strlen("-ERR")) == 0)
return FALSE;
return TRUE;
}
static void pop_data_reassemble_init (void)
{
fragment_table_init (&pop_data_segment_table);
reassembled_table_init (&pop_data_reassembled_table);
}
void
proto_register_pop(void)
{
static hf_register_info hf[] = {
{ &hf_pop_response,
{ "Response", "pop.response",
FT_STRING, BASE_NONE, NULL, 0x0,
"Response", HFILL }},
{ &hf_pop_response_indicator,
{ "Response indicator", "pop.response.indicator",
FT_STRING, BASE_NONE, NULL, 0x0,
"Response indicator", HFILL }},
{ &hf_pop_response_description,
{ "Response description", "pop.response.description",
FT_STRING, BASE_NONE, NULL, 0x0,
"Response description", HFILL }},
{ &hf_pop_response_data,
{ "Data", "pop.response.data",
FT_STRING, BASE_NONE, NULL, 0x0,
"Response Data", HFILL }},
{ &hf_pop_request,
{ "Request", "pop.request",
FT_STRING, BASE_NONE, NULL, 0x0,
"Request", HFILL }},
{ &hf_pop_request_command,
{ "Request command", "pop.request.command",
FT_STRING, BASE_NONE, NULL, 0x0,
"Request command", HFILL }},
{ &hf_pop_request_parameter,
{ "Request parameter", "pop.request.parameter",
FT_STRING, BASE_NONE, NULL, 0x0,
"Request parameter", HFILL }},
{ &hf_pop_request_data,
{ "Data", "pop.request.data",
FT_STRING, BASE_NONE, NULL, 0x0,
"Request data", HFILL }},
/* Fragment entries */
{ &hf_pop_data_fragments,
{ "DATA fragments", "pop.data.fragments", FT_NONE, BASE_NONE,
NULL, 0x00, "Message fragments", HFILL } },
{ &hf_pop_data_fragment,
{ "DATA fragment", "pop.data.fragment", FT_FRAMENUM, BASE_NONE,
NULL, 0x00, "Message fragment", HFILL } },
{ &hf_pop_data_fragment_overlap,
{ "DATA fragment overlap", "pop.data.fragment.overlap", FT_BOOLEAN,
BASE_NONE, NULL, 0x00, "Message fragment overlap", HFILL } },
{ &hf_pop_data_fragment_overlap_conflicts,
{ "DATA fragment overlapping with conflicting data",
"pop.data.fragment.overlap.conflicts", FT_BOOLEAN, BASE_NONE, NULL,
0x00, "Message fragment overlapping with conflicting data", HFILL } },
{ &hf_pop_data_fragment_multiple_tails,
{ "DATA has multiple tail fragments",
"pop.data.fragment.multiple_tails", FT_BOOLEAN, BASE_NONE,
NULL, 0x00, "Message has multiple tail fragments", HFILL } },
{ &hf_pop_data_fragment_too_long_fragment,
{ "DATA fragment too long", "pop.data.fragment.too_long_fragment",
FT_BOOLEAN, BASE_NONE, NULL, 0x00, "Message fragment too long",
HFILL } },
{ &hf_pop_data_fragment_error,
{ "DATA defragmentation error", "pop.data.fragment.error", FT_FRAMENUM,
BASE_NONE, NULL, 0x00, "Message defragmentation error", HFILL } },
{ &hf_pop_data_reassembled_in,
{ "Reassembled DATA in frame", "pop.data.reassembled.in", FT_FRAMENUM, BASE_NONE,
NULL, 0x00, "This DATA fragment is reassembled in this frame", HFILL } },
};
static gint *ett[] = {
&ett_pop,
&ett_pop_reqresp,
&ett_pop_data_fragment,
&ett_pop_data_fragments
};
module_t *pop_module;
proto_pop = proto_register_protocol("Post Office Protocol", "POP", "pop");
register_dissector("pop", dissect_pop, proto_pop);
proto_register_field_array(proto_pop, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_init_routine (&pop_data_reassemble_init);
/* Preferences */
pop_module = prefs_register_protocol(proto_pop, NULL);
prefs_register_bool_preference(pop_module, "desegment_data",
"Reassemble POP RETR and TOP responses spanning multiple TCP segments",
"Whether the POP dissector should reassemble RETR and TOP responses and spanning multiple TCP segments."
" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
&pop_data_desegment);
}
void
proto_reg_handoff_pop(void)
{
dissector_handle_t pop_handle;
pop_handle = find_dissector("pop");
dissector_add("tcp.port", TCP_PORT_POP, pop_handle);
ssl_dissector_add(TCP_PORT_SSL_POP, "pop", TRUE);
data_handle = find_dissector("data");
/* find the IMF dissector */
imf_handle = find_dissector("imf");
}
|