/* packet-tcp.c
* Routines for TCP packet disassembly
*
- * $Id: packet-tcp.c,v 1.88 2000/11/18 10:38:25 guy Exp $
+ * $Id: packet-tcp.c,v 1.113 2001/11/03 00:58:50 guy Exp $
*
* Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@zing.org>
+ * By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
- *
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
#include <stdio.h>
#include <string.h>
#include <glib.h>
+#include "in_cksum.h"
#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif
-#include "globals.h"
#include "resolv.h"
+#include "ipproto.h"
#include "follow.h"
#include "prefs.h"
-#include "plugins.h"
#include "packet-tcp.h"
#include "packet-ip.h"
#include "conversation.h"
#include "strutil.h"
+#include "reassemble.h"
/* Place TCP summary in proto tree */
-gboolean g_tcp_summary_in_tree = TRUE;
+static gboolean tcp_summary_in_tree = TRUE;
extern FILE* data_out_file;
-guint16 tcp_urgent_pointer;
-
-static gchar info_str[COL_MAX_LEN];
-static int info_len;
-
static int proto_tcp = -1;
static int hf_tcp_srcport = -1;
static int hf_tcp_dstport = -1;
static int hf_tcp_flags_fin = -1;
static int hf_tcp_window_size = -1;
static int hf_tcp_checksum = -1;
+static int hf_tcp_checksum_bad = -1;
static int hf_tcp_urgent_pointer = -1;
static gint ett_tcp = -1;
static gint ett_tcp_flags = -1;
static gint ett_tcp_options = -1;
static gint ett_tcp_option_sack = -1;
+static gint ett_tcp_segments = -1;
static dissector_table_t subdissector_table;
static heur_dissector_list_t heur_subdissector_list;
-
-/* TCP Ports */
-
-#define TCP_PORT_SMTP 25
+static conv_dissector_list_t conv_subdissector_list;
/* TCP structs and definitions */
-typedef struct _e_tcphdr {
- guint16 th_sport;
- guint16 th_dport;
- guint32 th_seq;
- guint32 th_ack;
- guint8 th_off_x2; /* combines th_off and th_x2 */
- guint8 th_flags;
#define TH_FIN 0x01
#define TH_SYN 0x02
#define TH_RST 0x04
#define TH_URG 0x20
#define TH_ECN 0x40
#define TH_CWR 0x80
- guint16 th_win;
- guint16 th_sum;
- guint16 th_urp;
-} e_tcphdr;
+
+/* Minimum TCP header length. */
+#define TCPH_MIN_LEN 20
/*
* TCP option
#define TCPOPT_CC 11
#define TCPOPT_CCNEW 12
#define TCPOPT_CCECHO 13
+#define TCPOPT_MD5 19 /* RFC2385 */
/*
* TCP option lengths
#define TCPOLEN_CC 6
#define TCPOLEN_CCNEW 6
#define TCPOLEN_CCECHO 6
+#define TCPOLEN_MD5 18
+
+
+/* Desegmentation of TCP streams */
+/* table to hold defragmented TCP streams */
+static GHashTable *tcp_fragment_table = NULL;
static void
-tcp_info_append_uint(const char *abbrev, guint32 val) {
- int add_len = 0;
-
- if (info_len > 0)
- if(info_len > 0)
- add_len = snprintf(&info_str[info_len], COL_MAX_LEN - info_len, " %s=%u",
- abbrev, val);
- if (add_len > 0)
- info_len += add_len;
+tcp_fragment_init(void)
+{
+ fragment_table_init(&tcp_fragment_table);
+}
+
+/* functions to trace tcp segments */
+/* Enable desegmenting of TCP streams */
+static gboolean tcp_desegment = FALSE;
+
+static GHashTable *tcp_segment_table = NULL;
+static GMemChunk *tcp_segment_key_chunk = NULL;
+static int tcp_segment_init_count = 200;
+static GMemChunk *tcp_segment_address_chunk = NULL;
+static int tcp_segment_address_init_count = 500;
+
+typedef struct _tcp_segment_key {
+ /* for ouwn bookkeeping inside packet-tcp.c */
+ address *src;
+ address *dst;
+ guint32 seq;
+ /* xxx */
+ guint32 start_seq;
+ guint32 tot_len;
+ guint32 first_frame;
+} tcp_segment_key;
+
+static gboolean
+free_all_segments(gpointer key_arg, gpointer value, gpointer user_data)
+{
+ tcp_segment_key *key = key_arg;
+
+ if((key->src)&&(key->src->data)){
+ g_free((gpointer)key->src->data);
+ key->src->data=NULL;
+ }
+
+ if((key->dst)&&(key->dst->data)){
+ g_free((gpointer)key->dst->data);
+ key->dst->data=NULL;
+ }
+
+ return TRUE;
+}
+
+static guint
+tcp_segment_hash(gconstpointer k)
+{
+ tcp_segment_key *key = (tcp_segment_key *)k;
+
+ return key->seq;
+}
+
+static gint
+tcp_segment_equal(gconstpointer k1, gconstpointer k2)
+{
+ tcp_segment_key *key1 = (tcp_segment_key *)k1;
+ tcp_segment_key *key2 = (tcp_segment_key *)k2;
+
+ return ( ( (key1->seq==key2->seq)
+ &&(ADDRESSES_EQUAL(key1->src, key2->src))
+ &&(ADDRESSES_EQUAL(key1->dst, key2->dst))
+ ) ? TRUE:FALSE);
+}
+
+static void
+tcp_desegment_init(void)
+{
+
+ /* dont allocate any memory chunks unless the user really
+ uses this option
+ */
+ if(!tcp_desegment){
+ return;
+ }
+
+ if(tcp_segment_table){
+ g_hash_table_foreach_remove(tcp_segment_table,
+ free_all_segments, NULL);
+ } else {
+ tcp_segment_table = g_hash_table_new(tcp_segment_hash,
+ tcp_segment_equal);
+ }
+
+ if(tcp_segment_key_chunk){
+ g_mem_chunk_destroy(tcp_segment_key_chunk);
+ }
+ tcp_segment_key_chunk = g_mem_chunk_new("tcp_segment_key_chunk",
+ sizeof(tcp_segment_key),
+ tcp_segment_init_count*sizeof(tcp_segment_key),
+ G_ALLOC_ONLY);
+
+ if(tcp_segment_address_chunk){
+ g_mem_chunk_destroy(tcp_segment_address_chunk);
+ }
+ tcp_segment_address_chunk = g_mem_chunk_new("tcp_segment_address_chunk",
+ sizeof(address),
+ tcp_segment_address_init_count*sizeof(address),
+ G_ALLOC_ONLY);
+}
+
+static void
+desegment_tcp(tvbuff_t *tvb, packet_info *pinfo, int offset,
+ guint32 seq, guint32 nxtseq,
+ guint32 sport, guint32 dport,
+ proto_tree *tree, proto_tree *tcp_tree)
+{
+ struct tcpinfo *tcpinfo = pinfo->private_data;
+ fragment_data *ipfd_head;
+ tcp_segment_key old_tsk, *tsk;
+ gboolean must_desegment = FALSE;
+ gboolean called_dissector = FALSE;
+ int deseg_offset;
+ guint32 deseg_seq;
+
+ /*
+ * Initialize these to assume no desegmentation.
+ * If that's not the case, these will be set appropriately
+ * by the subdissector.
+ */
+ pinfo->desegment_offset = 0;
+ pinfo->desegment_len = 0;
+
+ /*
+ * Initialize this to assume that this segment will just be
+ * added to the middle of a desegmented chunk of data, so
+ * that we should show it all as data.
+ * If that's not the case, it will be set appropriately.
+ */
+ deseg_offset = offset;
+
+ /* First we must check if this TCP segment should be desegmented.
+ This is only to check if we should desegment this packet,
+ so we dont spend time doing COPY_ADDRESS/g_free.
+ We just "borrow" some address structures from pinfo instead. Cheaper.
+ */
+ old_tsk.src = &pinfo->src;
+ old_tsk.dst = &pinfo->dst;
+ old_tsk.seq = seq;
+ tsk = g_hash_table_lookup(tcp_segment_table, &old_tsk);
+
+ if(tsk){
+ /* OK, this segment was found, which means it continues
+ a higher-level PDU. This means we must desegment it.
+ Add it to the defragmentation lists.
+ */
+ ipfd_head = fragment_add(tvb, offset, pinfo, tsk->start_seq,
+ tcp_fragment_table,
+ seq - tsk->start_seq,
+ nxtseq - seq,
+ (nxtseq < (tsk->start_seq + tsk->tot_len)) );
+
+ if(!ipfd_head){
+ /* fragment_add() returned NULL, This means that
+ desegmentation is not completed yet.
+ (its like defragmentation but we know we will
+ always add the segments in order).
+ XXX - no, we don't; there is no guarantee that
+ TCP segments are in order on the wire.
+
+ we must add next segment to our table so we will
+ find it later.
+ */
+ tcp_segment_key *new_tsk;
+
+ new_tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
+ memcpy(new_tsk, tsk, sizeof(tcp_segment_key));
+ new_tsk->seq=nxtseq;
+ g_hash_table_insert(tcp_segment_table,new_tsk,new_tsk);
+ }
+ } else {
+ /* This segment was not found in our table, so it doesn't
+ contain a continuation of a higher-level PDU.
+ Call the normal subdissector.
+ */
+ decode_tcp_ports(tvb, offset, pinfo, tree,
+ sport, dport);
+ called_dissector = TRUE;
+
+ /* Did the subdissector ask us to desegment some more data
+ before it could handle the packet?
+ If so we have to create some structures in our table but
+ this is something we only do the first time we see this
+ packet.
+ */
+ if(pinfo->desegment_len) {
+ if (!pinfo->fd->flags.visited)
+ must_desegment = TRUE;
+
+ /*
+ * Set "deseg_offset" to the offset in "tvb"
+ * of the first byte of data that the
+ * subdissector didn't process.
+ */
+ deseg_offset = offset + pinfo->desegment_offset;
+ }
+
+ /* Either no desegmentation is necessary, or this is
+ segment contains the beginning but not the end of
+ a higher-level PDU and thus isn't completely
+ desegmented.
+ */
+ ipfd_head = NULL;
+ }
+
+ /* is it completely desegmented? */
+ if(ipfd_head){
+ fragment_data *ipfd;
+ proto_tree *st = NULL;
+ proto_item *si = NULL;
+
+ /* first we show a tree with all segments */
+ si = proto_tree_add_text(tcp_tree, tvb, 0, 0,
+ "Segments");
+ st = proto_item_add_subtree(si, ett_tcp_segments);
+ for(ipfd=ipfd_head->next; ipfd; ipfd=ipfd->next){
+ proto_tree_add_text(st, tvb, 0, 0,
+ "Frame:%d seq#:%d-%d [%d-%d]",
+ ipfd->frame,
+ tsk->start_seq + ipfd->offset,
+ tsk->start_seq + ipfd->offset + ipfd->len - 1,
+ ipfd->offset,
+ ipfd->offset + ipfd->len - 1);
+ }
+
+ /*
+ * We only call subdissector for the last segment.
+ * Note that the last segment may include more than what
+ * we needed.
+ */
+ if(nxtseq >= (tsk->start_seq + tsk->tot_len)){
+ /* ok, lest call subdissector with desegmented data */
+ packet_info save_pi;
+ tvbuff_t *next_tvb;
+
+ /* create a new TVB structure for desegmented data */
+ next_tvb = tvb_new_real_data(ipfd_head->data,
+ ipfd_head->datalen, ipfd_head->datalen,
+ "Desegmented");
+
+ /* add this tvb as a child to the original one */
+ tvb_set_child_real_data_tvbuff(tvb, next_tvb);
+
+ /* add desegmented data to the data source list */
+ pinfo->fd->data_src = g_slist_append(pinfo->fd->data_src, next_tvb);
+
+ /* indicate that this is reassembled data */
+ tcpinfo->is_reassembled = TRUE;
+
+ /* save current value of *pinfo across call to
+ dissector */
+ save_pi = *pinfo;
+ pinfo->compat_top_tvb = next_tvb;
+ pinfo->len = tvb_reported_length(next_tvb);
+ pinfo->captured_len = tvb_length(next_tvb);
+
+ /* call subdissector */
+ decode_tcp_ports(next_tvb, 0, pinfo, tree,
+ sport, dport);
+ called_dissector = TRUE;
+
+ /*
+ * Don't trash the new values of "desegment_offset"
+ * and "desegment_len".
+ */
+ save_pi.desegment_offset = pinfo->desegment_offset;
+ save_pi.desegment_len = pinfo->desegment_len;
+ *pinfo = save_pi;
+
+ /* Did the subdissector ask us to desegment some more
+ data? This means that the data at the beginning
+ of this segment completed a higher-level PDU,
+ but the data at the end of this segment started
+ a higher-level PDU but didn't complete it.
+
+ If so we have to create some structures in our
+ table but this is something we only do the first
+ time we see this packet.
+ */
+ if(pinfo->desegment_len) {
+ if (!pinfo->fd->flags.visited)
+ must_desegment = TRUE;
+
+ /*
+ * The stuff we couldn't dissect must have
+ * come from this segment, so it's all in
+ * "tvb".
+ *
+ * "pinfo->desegment_offset" is relative
+ * to the beginning of "next_tvb";
+ * we want an offset relative to the
+ * beginning of "tvb".
+ *
+ * First, compute the offset relative to
+ * the *end* of "next_tvb" - i.e., the number
+ * of bytes before the end of "next_tvb"
+ * at which the subdissector stopped.
+ * That's the length of "next_tvb" minus
+ * the offset, relative to the beginning
+ * of "next_tvb, at which the subdissector
+ * stopped.
+ */
+ deseg_offset =
+ ipfd_head->datalen - pinfo->desegment_offset;
+
+ /*
+ * "tvb" and "next_tvb" end at the same byte
+ * of data, so the offset relative to the
+ * end of "next_tvb" of the byte at which
+ * we stopped is also the offset relative
+ * to the end of "tvb" of the byte at which
+ * we stopped.
+ *
+ * Convert that back into an offset relative
+ * to the beginninng of "tvb", by taking
+ * the length of "tvb" and subtracting the
+ * offset relative to the end.
+ */
+ deseg_offset = tvb_length(tvb) - deseg_offset;
+ }
+ }
+ }
+
+ if (must_desegment) {
+ tcp_segment_key *tsk, *new_tsk;
+
+ /*
+ * The sequence number at which the stuff to be desegmented
+ * starts is the sequence number of the byte at an offset
+ * of "deseg_offset" into "tvb".
+ *
+ * The sequence number of the byte at an offset of "offset"
+ * is "seq", i.e. the starting sequence number of this
+ * segment, so the sequence number of the byte at
+ * "deseg_offset" is "seq + (deseg_offset - offset)".
+ */
+ deseg_seq = seq + (deseg_offset - offset);
+
+ /*
+ * XXX - how do we detect out-of-order transmissions?
+ * We can't just check for "nxtseq" being greater than
+ * "tsk->start_seq"; for now, we check for the difference
+ * being less than a megabyte, but this is a really
+ * gross hack - we really need to handle out-of-order
+ * transmissions correctly.
+ */
+ if ((nxtseq - deseg_seq) <= 1024*1024) {
+ /* OK, subdissector wants us to desegment
+ some data before it can process it. Add
+ what remains of this packet and set
+ up next packet/sequence number as well.
+
+ We must remember this segment
+ */
+ tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
+ tsk->src = g_mem_chunk_alloc(tcp_segment_address_chunk);
+ COPY_ADDRESS(tsk->src, &pinfo->src);
+ tsk->dst = g_mem_chunk_alloc(tcp_segment_address_chunk);
+ COPY_ADDRESS(tsk->dst, &pinfo->dst);
+ tsk->seq = deseg_seq;
+ tsk->start_seq = tsk->seq;
+ tsk->tot_len = nxtseq - tsk->start_seq + pinfo->desegment_len;
+ tsk->first_frame = pinfo->fd->num;
+ g_hash_table_insert(tcp_segment_table, tsk, tsk);
+
+ /* Add portion of segment unprocessed by the subdissector
+ to defragmentation lists */
+ fragment_add(tvb, deseg_offset, pinfo, tsk->start_seq,
+ tcp_fragment_table,
+ tsk->seq - tsk->start_seq,
+ nxtseq - tsk->start_seq,
+ (nxtseq < tsk->start_seq + tsk->tot_len));
+
+ /* this is the next segment in the sequence we want */
+ new_tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
+ memcpy(new_tsk, tsk, sizeof(tcp_segment_key));
+ new_tsk->seq = nxtseq;
+ g_hash_table_insert(tcp_segment_table,new_tsk,new_tsk);
+ }
+ }
+
+ if (!called_dissector || pinfo->desegment_len != 0) {
+ /*
+ * Either we didn't call the subdissector at all (i.e.,
+ * this is a segment that contains the middle of a
+ * higher-level PDU, but contains neither the beginning
+ * nor the end), or the subdissector couldn't dissect it
+ * all, as some data was missing (i.e., it set
+ * "pinfo->desegment_len" to the amount of additional
+ * data it needs).
+ */
+ if (pinfo->desegment_offset == 0) {
+ /*
+ * It couldn't, in fact, dissect any of it (the
+ * first byte it couldn't dissect is at an offset
+ * of "pinfo->desegment_offset" from the beginning
+ * of the payload, and that's 0).
+ * Just mark this as TCP.
+ */
+ if (check_col(pinfo->fd, COL_PROTOCOL)){
+ col_set_str(pinfo->fd, COL_PROTOCOL, "TCP");
+ }
+ if (check_col(pinfo->fd, COL_INFO)){
+ col_set_str(pinfo->fd, COL_INFO, "[Desegmented TCP]");
+ }
+ }
+
+ /*
+ * Show what's left in the packet as data.
+ */
+ dissect_data(tvb, deseg_offset, pinfo, tree);
+ }
+}
+
+
+
+
+static void
+tcp_info_append_uint(frame_data *fd, const char *abbrev, guint32 val)
+{
+ if (check_col(fd, COL_INFO))
+ col_append_fstr(fd, COL_INFO, " %s=%u", abbrev, val);
}
static void
dissect_tcpopt_maxseg(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
guint16 mss;
mss = tvb_get_ntohs(tvb, offset + 2);
proto_tree_add_text(opt_tree, tvb, offset, optlen,
"%s: %u bytes", optp->name, mss);
- tcp_info_append_uint("MSS", mss);
+ tcp_info_append_uint(fd, "MSS", mss);
}
static void
dissect_tcpopt_wscale(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
guint8 ws;
ws = tvb_get_guint8(tvb, offset + 2);
proto_tree_add_text(opt_tree, tvb, offset, optlen,
"%s: %u bytes", optp->name, ws);
- tcp_info_append_uint("WS", ws);
+ tcp_info_append_uint(fd, "WS", ws);
}
static void
dissect_tcpopt_sack(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
proto_tree *field_tree = NULL;
proto_item *tf;
optlen -= 4;
proto_tree_add_text(field_tree, tvb, offset, 8,
"left edge = %u, right edge = %u", leftedge, rightedge);
- tcp_info_append_uint("SLE", leftedge);
- tcp_info_append_uint("SRE", rightedge);
+ tcp_info_append_uint(fd, "SLE", leftedge);
+ tcp_info_append_uint(fd, "SRE", rightedge);
offset += 8;
}
}
static void
dissect_tcpopt_echo(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
guint32 echo;
echo = tvb_get_ntohl(tvb, offset + 2);
proto_tree_add_text(opt_tree, tvb, offset, optlen,
"%s: %u", optp->name, echo);
- tcp_info_append_uint("ECHO", echo);
+ tcp_info_append_uint(fd, "ECHO", echo);
}
static void
dissect_tcpopt_timestamp(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
guint32 tsv, tser;
tser = tvb_get_ntohl(tvb, offset + 6);
proto_tree_add_text(opt_tree, tvb, offset, optlen,
"%s: tsval %u, tsecr %u", optp->name, tsv, tser);
- tcp_info_append_uint("TSV", tsv);
- tcp_info_append_uint("TSER", tser);
+ tcp_info_append_uint(fd, "TSV", tsv);
+ tcp_info_append_uint(fd, "TSER", tser);
}
static void
dissect_tcpopt_cc(const ip_tcp_opt *optp, tvbuff_t *tvb,
- int offset, guint optlen, proto_tree *opt_tree)
+ int offset, guint optlen, frame_data *fd, proto_tree *opt_tree)
{
guint32 cc;
cc = tvb_get_ntohl(tvb, offset + 2);
proto_tree_add_text(opt_tree, tvb, offset, optlen,
"%s: %u", optp->name, cc);
- tcp_info_append_uint("CC", cc);
+ tcp_info_append_uint(fd, "CC", cc);
}
static const ip_tcp_opt tcpopts[] = {
"CC.NEW",
NULL,
FIXED_LENGTH,
- TCPOPT_CCNEW,
+ TCPOLEN_CCNEW,
dissect_tcpopt_cc
},
{
FIXED_LENGTH,
TCPOLEN_CCECHO,
dissect_tcpopt_cc
+ },
+ {
+ TCPOPT_MD5,
+ "TCP MD5 signature",
+ NULL,
+ FIXED_LENGTH,
+ TCPOLEN_MD5,
+ NULL
}
};
proto_tree *tree, int src_port, int dst_port)
{
tvbuff_t *next_tvb;
- const u_char *next_pd;
- int next_offset;
next_tvb = tvb_new_subset(tvb, offset, -1, -1);
if (try_conversation_dissector(&pinfo->src, &pinfo->dst, PT_TCP,
src_port, dst_port, next_tvb, pinfo, tree))
- return;
-
- /* try to apply the plugins */
-#ifdef HAVE_PLUGINS
- {
- plugin *pt_plug = plugin_list;
-
- if (enabled_plugins_number > 0) {
- tvb_compat(next_tvb, &next_pd, &next_offset);
- while (pt_plug) {
- if (pt_plug->enabled && strstr(pt_plug->protocol, "tcp") &&
- tree && dfilter_apply(pt_plug->filter, tree, next_pd, pinfo->fd->cap_len)) {
- pt_plug->dissector(next_pd, next_offset, pinfo->fd, tree);
- return;
- }
- pt_plug = pt_plug->next;
- }
- }
- }
-#endif
+ return;
/* do lookup with the subdissector table */
if (dissector_try_port(subdissector_table, src_port, next_tvb, pinfo, tree) ||
static void
dissect_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
- e_tcphdr th;
+ guint16 th_sport;
+ guint16 th_dport;
+ guint32 th_seq;
+ guint32 th_ack;
+ guint8 th_off_x2; /* combines th_off and th_x2 */
+ guint8 th_flags;
+ guint16 th_win;
+ guint16 th_sum;
+ guint16 th_urp;
proto_tree *tcp_tree = NULL, *field_tree = NULL;
- proto_item *ti, *tf;
+ proto_item *ti = NULL, *tf;
int offset = 0;
gchar flags[64] = "<None>";
gchar *fstr[] = {"FIN", "SYN", "RST", "PSH", "ACK", "URG", "ECN", "CWR" };
guint optlen;
guint32 seglen;
guint32 nxtseq;
+ guint len;
+ guint reported_len;
+ vec_t cksum_vec[4];
+ guint32 phdr[2];
+ guint16 computed_cksum;
guint length_remaining;
+ struct tcpinfo tcpinfo;
- CHECK_DISPLAY_AS_DATA(proto_tcp, tvb, pinfo, tree);
-
- pinfo->current_proto = "TCP";
+ if (check_col(pinfo->fd, COL_PROTOCOL))
+ col_set_str(pinfo->fd, COL_PROTOCOL, "TCP");
- /* Avoids alignment problems on many architectures. */
- tvb_memcpy(tvb, (guint8 *)&th, offset, sizeof(e_tcphdr));
- th.th_sport = ntohs(th.th_sport);
- th.th_dport = ntohs(th.th_dport);
- th.th_win = ntohs(th.th_win);
- th.th_sum = ntohs(th.th_sum);
- th.th_urp = ntohs(th.th_urp);
- th.th_seq = ntohl(th.th_seq);
- th.th_ack = ntohl(th.th_ack);
+ /* Clear out the Info column. */
+ if (check_col(pinfo->fd, COL_INFO))
+ col_clear(pinfo->fd, COL_INFO);
- /* Export the urgent pointer, for the benefit of protocols such as
- rlogin. */
- tcp_urgent_pointer = th.th_urp;
-
- info_len = 0;
+ th_sport = tvb_get_ntohs(tvb, offset);
+ th_dport = tvb_get_ntohs(tvb, offset + 2);
+ if (check_col(pinfo->fd, COL_INFO)) {
+ col_append_fstr(pinfo->fd, COL_INFO, "%s > %s",
+ get_tcp_port(th_sport), get_tcp_port(th_dport));
+ }
+
+ if (tree) {
+ if (tcp_summary_in_tree) {
+ ti = proto_tree_add_protocol_format(tree, proto_tcp, tvb, 0,
+ tvb_length(tvb),
+ "Transmission Control Protocol, Src Port: %s (%u), Dst Port: %s (%u)",
+ get_tcp_port(th_sport), th_sport,
+ get_tcp_port(th_dport), th_dport);
+ }
+ else {
+ ti = proto_tree_add_item(tree, proto_tcp, tvb, 0,
+ tvb_length(tvb), FALSE);
+ }
+ tcp_tree = proto_item_add_subtree(ti, ett_tcp);
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_srcport, tvb, offset, 2, th_sport,
+ "Source port: %s (%u)", get_tcp_port(th_sport), th_sport);
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_dstport, tvb, offset + 2, 2, th_dport,
+ "Destination port: %s (%u)", get_tcp_port(th_dport), th_dport);
+ proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset, 2, th_sport);
+ proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset + 2, 2, th_dport);
+ }
+ th_seq = tvb_get_ntohl(tvb, offset + 4);
+ th_ack = tvb_get_ntohl(tvb, offset + 8);
+ th_off_x2 = tvb_get_guint8(tvb, offset + 12);
+ th_flags = tvb_get_guint8(tvb, offset + 13);
+ th_win = tvb_get_ntohs(tvb, offset + 14);
+
if (check_col(pinfo->fd, COL_INFO) || tree) {
for (i = 0; i < 8; i++) {
bpos = 1 << i;
- if (th.th_flags & bpos) {
+ if (th_flags & bpos) {
if (fpos) {
strcpy(&flags[fpos], ", ");
fpos += 2;
}
flags[fpos] = '\0';
}
-
- hlen = hi_nibble(th.th_off_x2) * 4; /* TCP header length, in bytes */
+
+ if (check_col(pinfo->fd, COL_INFO)) {
+ col_append_fstr(pinfo->fd, COL_INFO, " [%s] Seq=%u Ack=%u Win=%u",
+ flags, th_seq, th_ack, th_win);
+ }
+
+ if (tree) {
+ if (tcp_summary_in_tree)
+ proto_item_append_text(ti, ", Seq: %u", th_seq);
+ proto_tree_add_uint(tcp_tree, hf_tcp_seq, tvb, offset + 4, 4, th_seq);
+ }
+
+ hlen = hi_nibble(th_off_x2) * 4; /* TCP header length, in bytes */
+
+ if (hlen < TCPH_MIN_LEN) {
+ /* Give up at this point; we put the source and destination port in
+ the tree, before fetching the header length, so that they'll
+ show up if this is in the failing packet in an ICMP error packet,
+ but it's now time to give up if the header length is bogus. */
+ if (check_col(pinfo->fd, COL_INFO))
+ col_append_fstr(pinfo->fd, COL_INFO, ", bogus TCP header length (%u, must be at least %u)",
+ hlen, TCPH_MIN_LEN);
+ if (tree) {
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_hdr_len, tvb, offset + 12, 1, hlen,
+ "Header length: %u bytes (bogus, must be at least %u)", hlen,
+ TCPH_MIN_LEN);
+ }
+ return;
+ }
+
+ reported_len = tvb_reported_length(tvb);
+ len = tvb_length(tvb);
/* Compute the length of data in this segment. */
- seglen = tvb_reported_length(tvb) - hlen;
+ seglen = reported_len - hlen;
/* Compute the sequence number of next octet after this segment. */
- nxtseq = th.th_seq + seglen;
+ nxtseq = th_seq + seglen;
- if (check_col(pinfo->fd, COL_PROTOCOL))
- col_add_str(pinfo->fd, COL_PROTOCOL, "TCP");
- if (check_col(pinfo->fd, COL_INFO)) {
- /* Copy the data into info_str in case one of the option handling
- routines needs to append to it. */
- if (th.th_flags & TH_URG)
- info_len = snprintf(info_str, COL_MAX_LEN, "%s > %s [%s] Seq=%u Ack=%u Win=%u Urg=%u Len=%d",
- get_tcp_port(th.th_sport), get_tcp_port(th.th_dport), flags,
- th.th_seq, th.th_ack, th.th_win, th.th_urp, seglen);
- else
- info_len = snprintf(info_str, COL_MAX_LEN, "%s > %s [%s] Seq=%u Ack=%u Win=%u Len=%d",
- get_tcp_port(th.th_sport), get_tcp_port(th.th_dport), flags,
- th.th_seq, th.th_ack, th.th_win, seglen);
- /* The info column is actually written after the options are decoded */
- }
-
if (tree) {
- if (g_tcp_summary_in_tree) {
- ti = proto_tree_add_protocol_format(tree, proto_tcp, tvb, offset, hlen, "Transmission Control Protocol, Src Port: %s (%u), Dst Port: %s (%u), Seq: %u, Ack: %u", get_tcp_port(th.th_sport), th.th_sport, get_tcp_port(th.th_dport), th.th_dport, th.th_seq, th.th_ack);
- }
- else {
- ti = proto_tree_add_item(tree, proto_tcp, tvb, offset, hlen, FALSE);
- }
- tcp_tree = proto_item_add_subtree(ti, ett_tcp);
- proto_tree_add_uint_format(tcp_tree, hf_tcp_srcport, tvb, offset, 2, th.th_sport,
- "Source port: %s (%u)", get_tcp_port(th.th_sport), th.th_sport);
- proto_tree_add_uint_format(tcp_tree, hf_tcp_dstport, tvb, offset + 2, 2, th.th_dport,
- "Destination port: %s (%u)", get_tcp_port(th.th_dport), th.th_dport);
- proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset, 2, th.th_sport);
- proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset + 2, 2, th.th_dport);
- proto_tree_add_uint(tcp_tree, hf_tcp_seq, tvb, offset + 4, 4, th.th_seq);
- if (nxtseq != th.th_seq)
+ if (tcp_summary_in_tree)
+ proto_item_append_text(ti, ", Ack: %u", th_ack);
+ proto_item_set_len(ti, hlen);
+ if (nxtseq != th_seq)
proto_tree_add_uint(tcp_tree, hf_tcp_nxtseq, tvb, offset, 0, nxtseq);
- if (th.th_flags & TH_ACK)
- proto_tree_add_uint(tcp_tree, hf_tcp_ack, tvb, offset + 8, 4, th.th_ack);
+ if (th_flags & TH_ACK)
+ proto_tree_add_uint(tcp_tree, hf_tcp_ack, tvb, offset + 8, 4, th_ack);
proto_tree_add_uint_format(tcp_tree, hf_tcp_hdr_len, tvb, offset + 12, 1, hlen,
"Header length: %u bytes", hlen);
tf = proto_tree_add_uint_format(tcp_tree, hf_tcp_flags, tvb, offset + 13, 1,
- th.th_flags, "Flags: 0x%04x (%s)", th.th_flags, flags);
+ th_flags, "Flags: 0x%04x (%s)", th_flags, flags);
field_tree = proto_item_add_subtree(tf, ett_tcp_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_cwr, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_ecn, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_urg, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_ack, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_push, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_reset, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_syn, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_boolean(field_tree, hf_tcp_flags_fin, tvb, offset + 13, 1, th.th_flags);
- proto_tree_add_uint(tcp_tree, hf_tcp_window_size, tvb, offset + 14, 2, th.th_win);
- proto_tree_add_uint(tcp_tree, hf_tcp_checksum, tvb, offset + 16, 2, th.th_sum);
- if (th.th_flags & TH_URG)
- proto_tree_add_uint(tcp_tree, hf_tcp_urgent_pointer, tvb, offset + 18, 2, th.th_urp);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_cwr, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_ecn, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_urg, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_ack, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_push, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_reset, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_syn, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_boolean(field_tree, hf_tcp_flags_fin, tvb, offset + 13, 1, th_flags);
+ proto_tree_add_uint(tcp_tree, hf_tcp_window_size, tvb, offset + 14, 2, th_win);
}
+ /* Assume we'll pass un-reassembled data to subdissectors. */
+ tcpinfo.is_reassembled = FALSE;
+
+ pinfo->private_data = &tcpinfo;
+
+ /*
+ * Assume, initially, that we can't desegment.
+ */
+ pinfo->can_desegment = FALSE;
+
+ th_sum = tvb_get_ntohs(tvb, offset + 16);
+ if (!pinfo->fragmented && len >= reported_len) {
+ /* The packet isn't part of a fragmented datagram, isn't being
+ returned inside an ICMP error packet, and isn't truncated, so we
+ can checksum it.
+ XXX - make a bigger scatter-gather list once we do fragment
+ reassembly? */
+
+ /* Set up the fields of the pseudo-header. */
+ cksum_vec[0].ptr = pinfo->src.data;
+ cksum_vec[0].len = pinfo->src.len;
+ cksum_vec[1].ptr = pinfo->dst.data;
+ cksum_vec[1].len = pinfo->dst.len;
+ cksum_vec[2].ptr = (const guint8 *)&phdr;
+ switch (pinfo->src.type) {
+
+ case AT_IPv4:
+ phdr[0] = htonl((IP_PROTO_TCP<<16) + reported_len);
+ cksum_vec[2].len = 4;
+ break;
+
+ case AT_IPv6:
+ phdr[0] = htonl(reported_len);
+ phdr[1] = htonl(IP_PROTO_TCP);
+ cksum_vec[2].len = 8;
+ break;
+
+ default:
+ /* TCP runs only atop IPv4 and IPv6.... */
+ g_assert_not_reached();
+ break;
+ }
+ cksum_vec[3].ptr = tvb_get_ptr(tvb, offset, len);
+ cksum_vec[3].len = reported_len;
+ computed_cksum = in_cksum(&cksum_vec[0], 4);
+ if (computed_cksum == 0) {
+ /*
+ * We have all the data for this TCP segment, and the checksum of
+ * the header and the data is good, so we can desegment it.
+ * Is desegmentation enabled?
+ */
+ if (tcp_desegment) {
+ /* Yes - is this segment being returned in an error packet? */
+ if (!pinfo->in_error_pkt) {
+ /* No - indicate that we will desegment.
+ We do NOT want to desegment segments returned in error
+ packets, as they're not part of a TCP connection. */
+ pinfo->can_desegment = TRUE;
+ }
+ }
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
+ offset + 16, 2, th_sum, "Checksum: 0x%04x (correct)", th_sum);
+ } else {
+ proto_tree_add_boolean_hidden(tcp_tree, hf_tcp_checksum_bad, tvb,
+ offset + 16, 2, TRUE);
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
+ offset + 16, 2, th_sum,
+ "Checksum: 0x%04x (incorrect, should be 0x%04x)", th_sum,
+ in_cksum_shouldbe(th_sum, computed_cksum));
+ }
+ } else {
+ proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
+ offset + 16, 2, th_sum, "Checksum: 0x%04x", th_sum);
+ }
+ if (th_flags & TH_URG) {
+ th_urp = tvb_get_ntohs(tvb, offset + 18);
+ /* Export the urgent pointer, for the benefit of protocols such as
+ rlogin. */
+ tcpinfo.urgent = TRUE;
+ tcpinfo.urgent_pointer = th_urp;
+ if (check_col(pinfo->fd, COL_INFO))
+ col_append_fstr(pinfo->fd, COL_INFO, " Urg=%u", th_urp);
+ if (tcp_tree != NULL)
+ proto_tree_add_uint(tcp_tree, hf_tcp_urgent_pointer, tvb, offset + 18, 2, th_urp);
+ } else
+ tcpinfo.urgent = FALSE;
+
+ if (check_col(pinfo->fd, COL_INFO))
+ col_append_fstr(pinfo->fd, COL_INFO, " Len=%d", seglen);
+
/* Decode TCP options, if any. */
- if (tree && hlen > sizeof (e_tcphdr)) {
+ if (tree && hlen > TCPH_MIN_LEN) {
/* There's more than just the fixed-length header. Decode the
options. */
- optlen = hlen - sizeof (e_tcphdr); /* length of options, in bytes */
+ optlen = hlen - TCPH_MIN_LEN; /* length of options, in bytes */
tf = proto_tree_add_text(tcp_tree, tvb, offset + 20, optlen,
"Options: (%d bytes)", optlen);
field_tree = proto_item_add_subtree(tf, ett_tcp_options);
dissect_ip_tcp_options(tvb, offset + 20, optlen,
- tcpopts, N_TCP_OPTS, TCPOPT_EOL, field_tree);
+ tcpopts, N_TCP_OPTS, TCPOPT_EOL, pinfo->fd, field_tree);
}
- if (check_col(pinfo->fd, COL_INFO))
- col_add_str(pinfo->fd, COL_INFO, info_str);
-
/* Skip over header + options */
offset += hlen;
pinfo->ptype = PT_TCP;
- pinfo->srcport = th.th_sport;
- pinfo->destport = th.th_dport;
+ pinfo->srcport = th_sport;
+ pinfo->destport = th_dport;
/* Check the packet length to see if there's more data
(it could be an ACK-only packet) */
length_remaining = tvb_length_remaining(tvb, offset);
if (length_remaining != 0) {
- if (th.th_flags & TH_RST) {
+ if (th_flags & TH_RST) {
/*
* RFC1122 says:
*
proto_tree_add_text(tcp_tree, tvb, offset, length_remaining,
"Reset cause: %s",
tvb_format_text(tvb, offset, length_remaining));
- } else
- decode_tcp_ports( tvb, offset, pinfo, tree, th.th_sport, th.th_dport);
+ } else {
+ /* Can we desegment this segment? */
+ if (pinfo->can_desegment) {
+ /* Yes. */
+ desegment_tcp(tvb, pinfo, offset, th_seq, nxtseq, th_sport, th_dport, tree, tcp_tree);
+ } else {
+ /* No - just call the subdissector. */
+ decode_tcp_ports(tvb, offset, pinfo, tree, th_sport, th_dport);
+ }
+ }
}
if( data_out_file ) {
- reassemble_tcp( th.th_seq, /* sequence number */
+ reassemble_tcp( th_seq, /* sequence number */
seglen, /* data length */
tvb_get_ptr(tvb, offset, length_remaining), /* data */
length_remaining, /* captured data length */
- ( th.th_flags & TH_SYN ), /* is syn set? */
+ ( th_flags & TH_SYN ), /* is syn set? */
&pinfo->net_src,
&pinfo->net_dst,
pinfo->srcport,
{ &hf_tcp_srcport,
{ "Source Port", "tcp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_dstport,
{ "Destination Port", "tcp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_port,
{ "Source or Destination Port", "tcp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_seq,
{ "Sequence number", "tcp.seq", FT_UINT32, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_nxtseq,
{ "Next sequence number", "tcp.nxtseq", FT_UINT32, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_ack,
{ "Acknowledgement number", "tcp.ack", FT_UINT32, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_hdr_len,
{ "Header Length", "tcp.hdr_len", FT_UINT8, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags,
{ "Flags", "tcp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_cwr,
{ "Congestion Window Reduced (CWR)", "tcp.flags.cwr", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_CWR,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_ecn,
{ "ECN-Echo", "tcp.flags.ecn", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_ECN,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_urg,
{ "Urgent", "tcp.flags.urg", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_URG,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_ack,
{ "Acknowledgment", "tcp.flags.ack", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_ACK,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_push,
{ "Push", "tcp.flags.push", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_PUSH,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_reset,
{ "Reset", "tcp.flags.reset", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_RST,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_syn,
{ "Syn", "tcp.flags.syn", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_SYN,
- "" }},
+ "", HFILL }},
{ &hf_tcp_flags_fin,
{ "Fin", "tcp.flags.fin", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_FIN,
- "" }},
+ "", HFILL }},
{ &hf_tcp_window_size,
{ "Window size", "tcp.window_size", FT_UINT16, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
{ &hf_tcp_checksum,
{ "Checksum", "tcp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
- "" }},
+ "", HFILL }},
+
+ { &hf_tcp_checksum_bad,
+ { "Bad Checksum", "tcp.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+ "", HFILL }},
{ &hf_tcp_urgent_pointer,
{ "Urgent pointer", "tcp.urgent_pointer", FT_UINT16, BASE_DEC, NULL, 0x0,
- "" }},
+ "", HFILL }},
};
static gint *ett[] = {
&ett_tcp,
&ett_tcp_flags,
&ett_tcp_options,
&ett_tcp_option_sack,
+ &ett_tcp_segments,
};
module_t *tcp_module;
- proto_tcp = proto_register_protocol ("Transmission Control Protocol", "tcp");
+ proto_tcp = proto_register_protocol("Transmission Control Protocol",
+ "TCP", "tcp");
proto_register_field_array(proto_tcp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* subdissector code */
subdissector_table = register_dissector_table("tcp.port");
register_heur_dissector_list("tcp", &heur_subdissector_list);
+ register_conv_dissector_list("tcp", &conv_subdissector_list);
- /* Register a configuration preferences */
- tcp_module = prefs_register_module("tcp", "TCP", NULL);
+ /* Register configuration preferences */
+ tcp_module = prefs_register_protocol(proto_tcp, NULL);
prefs_register_bool_preference(tcp_module, "tcp_summary_in_tree",
"Show TCP summary in protocol tree",
"Whether the TCP summary line should be shown in the protocol tree",
- &g_tcp_summary_in_tree);
+ &tcp_summary_in_tree);
+ prefs_register_bool_preference(tcp_module, "desegment_tcp_streams",
+ "Allow subdissector to desegment TCP streams",
+"Whether subdissector can request TCP streams to be desegmented",
+ &tcp_desegment);
+
+ register_init_routine(tcp_desegment_init);
+ register_init_routine(tcp_fragment_init);
}
void
proto_reg_handoff_tcp(void)
{
- dissector_add("ip.proto", IP_PROTO_TCP, dissect_tcp);
+ dissector_add("ip.proto", IP_PROTO_TCP, dissect_tcp, proto_tcp);
}
git.samba.org / obnox / wireshark / wip.git / blobdiff