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wireshark/epan/dissectors/packet-udp.c

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/* packet-udp.c
* Routines for UDP/UDP-Lite packet disassembly
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Richard Sharpe, 13-Feb-1999, added dispatch table support and
* support for tftp.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#define NEW_PROTO_TREE_API
#include "config.h"
#include <epan/packet.h>
#include <epan/capture_dissectors.h>
#include <epan/addr_resolv.h>
#include <epan/ipproto.h>
#include <epan/in_cksum.h>
#include <epan/prefs.h>
#include <epan/follow.h>
#include <epan/expert.h>
#include <epan/exceptions.h>
#include <epan/show_exception.h>
#include <epan/proto_data.h>
#include <wsutil/utf8_entities.h>
#include <wsutil/pint.h>
#include <wsutil/str_util.h>
#include "packet-udp.h"
#include <epan/conversation.h>
#include <epan/conversation_table.h>
#include <epan/conversation_filter.h>
#include <epan/exported_pdu.h>
#include <epan/decode_as.h>
void proto_register_udp(void);
void proto_reg_handoff_udp(void);
static dissector_handle_t udp_handle;
static dissector_handle_t udplite_handle;
static int udp_tap = -1;
static int udp_follow_tap = -1;
static int exported_pdu_tap = -1;
static header_field_info *hfi_udp = NULL;
static header_field_info *hfi_udplite = NULL;
#define UDP_HFI_INIT HFI_INIT(proto_udp)
#define UDPLITE_HFI_INIT HFI_INIT(proto_udplite)
static header_field_info hfi_udp_srcport UDP_HFI_INIT =
{ "Source Port", "udp.srcport", FT_UINT16, BASE_PT_UDP, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_dstport UDP_HFI_INIT =
{ "Destination Port", "udp.dstport", FT_UINT16, BASE_PT_UDP, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_port UDP_HFI_INIT =
{ "Source or Destination Port", "udp.port", FT_UINT16, BASE_PT_UDP, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_stream UDP_HFI_INIT =
{ "Stream index", "udp.stream", FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_length UDP_HFI_INIT =
{ "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_checksum UDP_HFI_INIT =
{ "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
"Details at: https://www.wireshark.org/docs/wsug_html_chunked/ChAdvChecksums.html", HFILL };
static header_field_info hfi_udp_checksum_calculated UDP_HFI_INIT =
{ "Calculated Checksum", "udp.checksum_calculated", FT_UINT16, BASE_HEX, NULL, 0x0,
"The expected UDP checksum field as calculated from the UDP packet", HFILL };
static header_field_info hfi_udp_checksum_status UDP_HFI_INIT =
{ "Checksum Status", "udp.checksum.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL };
static header_field_info hfi_udp_proc_src_uid UDP_HFI_INIT =
{ "Source process user ID", "udp.proc.srcuid", FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_src_pid UDP_HFI_INIT =
{ "Source process ID", "udp.proc.srcpid", FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_src_uname UDP_HFI_INIT =
{ "Source process user name", "udp.proc.srcuname", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_src_cmd UDP_HFI_INIT =
{ "Source process name", "udp.proc.srccmd", FT_STRING, BASE_NONE, NULL, 0x0,
"Source process command name", HFILL};
static header_field_info hfi_udp_proc_dst_uid UDP_HFI_INIT =
{ "Destination process user ID", "udp.proc.dstuid", FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_dst_pid UDP_HFI_INIT =
{ "Destination process ID", "udp.proc.dstpid", FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_dst_uname UDP_HFI_INIT =
{ "Destination process user name", "udp.proc.dstuname", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL};
static header_field_info hfi_udp_proc_dst_cmd UDP_HFI_INIT =
{ "Destination process name", "udp.proc.dstcmd", FT_STRING, BASE_NONE, NULL, 0x0,
"Destination process command name", HFILL};
static header_field_info hfi_udp_pdu_size UDP_HFI_INIT =
{ "PDU Size", "udp.pdu.size", FT_UINT32, BASE_DEC, NULL, 0x0,
"The size of this PDU", HFILL };
static header_field_info hfi_udp_ts_relative UDP_HFI_INIT =
{ "Time since first frame", "udp.time_relative", FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
"Time relative to first frame in this UDP stream", HFILL };
static header_field_info hfi_udp_ts_delta UDP_HFI_INIT =
{ "Time since previous frame", "udp.time_delta", FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
"Time delta from previous frame in this UDP stream", HFILL };
static header_field_info hfi_udplite_checksum_coverage UDPLITE_HFI_INIT =
{ "Checksum coverage", "udp.checksum_coverage", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL };
static header_field_info hfi_udp_payload UDP_HFI_INIT =
{ "Payload", "udp.payload", FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL };
static gint ett_udp = -1;
static gint ett_udp_checksum = -1;
static gint ett_udp_process_info = -1;
static gint ett_udp_timestamps = -1;
static expert_field ei_udp_possible_traceroute = EI_INIT;
static expert_field ei_udp_length_bad = EI_INIT;
static expert_field ei_udplite_checksum_coverage_bad = EI_INIT;
static expert_field ei_udp_checksum_zero = EI_INIT;
static expert_field ei_udp_checksum_bad = EI_INIT;
static expert_field ei_udp_length_bad_zero = EI_INIT;
/* Preferences */
/* Place UDP summary in proto tree */
static gboolean udp_summary_in_tree = TRUE;
/* Check UDP checksums */
static gboolean udp_check_checksum = FALSE;
/* Collect IPFIX process flow information */
static gboolean udp_process_info = FALSE;
/* Ignore an invalid checksum coverage field for UDP-Lite */
static gboolean udplite_ignore_checksum_coverage = TRUE;
/* Check UDP-Lite checksums */
static gboolean udplite_check_checksum = FALSE;
static dissector_table_t udp_dissector_table;
static heur_dissector_list_t heur_subdissector_list;
static guint32 udp_stream_count;
/* Determine if there is a sub-dissector and call it. This has been */
/* separated into a stand alone routine so other protocol dissectors */
/* can call to it, ie. socks */
static gboolean try_heuristic_first = FALSE;
static gboolean udp_calculate_ts = TRUE;
static gboolean udplite_calculate_ts = TRUE;
/* Per-packet-info for UDP */
typedef struct
{
heur_dtbl_entry_t *heur_dtbl_entry;
nstime_t ts_delta;
gboolean ts_delta_valid;
} udp_p_info_t;
static void
udp_src_prompt(packet_info *pinfo, gchar *result)
{
guint32 port = GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, hfi_udp_srcport.id, pinfo->curr_layer_num));
g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "source (%u%s)", port, UTF8_RIGHTWARDS_ARROW);
}
static gpointer
udp_src_value(packet_info *pinfo)
{
return p_get_proto_data(pinfo->pool, pinfo, hfi_udp_srcport.id, pinfo->curr_layer_num);
}
static void
udp_dst_prompt(packet_info *pinfo, gchar *result)
{
guint32 port = GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, hfi_udp_dstport.id, pinfo->curr_layer_num));
g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "destination (%s%u)", UTF8_RIGHTWARDS_ARROW, port);
}
static gpointer
udp_dst_value(packet_info *pinfo)
{
return p_get_proto_data(pinfo->pool, pinfo, hfi_udp_dstport.id, pinfo->curr_layer_num);
}
static void
udp_both_prompt(packet_info *pinfo, gchar *result)
{
guint32 srcport = GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, hfi_udp_srcport.id, pinfo->curr_layer_num)),
dstport = GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, hfi_udp_dstport.id, pinfo->curr_layer_num));
g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Both (%u%s%u)", srcport, UTF8_LEFT_RIGHT_ARROW, dstport);
}
/* Conversation and process code originally copied from packet-tcp.c */
static struct udp_analysis *
init_udp_conversation_data(packet_info *pinfo)
{
struct udp_analysis *udpd;
/* Initialize the udp protocol data structure to add to the udp conversation */
udpd = wmem_new0(wmem_file_scope(), struct udp_analysis);
/*
udpd->flow1.username = NULL;
udpd->flow1.command = NULL;
udpd->flow2.username = NULL;
udpd->flow2.command = NULL;
*/
udpd->stream = udp_stream_count++;
udpd->ts_first = pinfo->abs_ts;
udpd->ts_prev = pinfo->abs_ts;
return udpd;
}
struct udp_analysis *
get_udp_conversation_data(conversation_t *conv, packet_info *pinfo)
{
int direction;
struct udp_analysis *udpd=NULL;
/* Did the caller supply the conversation pointer? */
if (conv == NULL)
conv = find_or_create_conversation(pinfo);
/* Get the data for this conversation */
udpd=(struct udp_analysis *)conversation_get_proto_data(conv, hfi_udp->id);
/* If the conversation was just created or it matched a
* conversation with template options, udpd will not
* have been initialized. So, initialize
* a new udpd structure for the conversation.
*/
if (!udpd) {
udpd = init_udp_conversation_data(pinfo);
conversation_add_proto_data(conv, hfi_udp->id, udpd);
}
if (!udpd) {
return NULL;
}
/* check direction and get ua lists */
direction=cmp_address(&pinfo->src, &pinfo->dst);
/* if the addresses are equal, match the ports instead */
if (direction == 0) {
direction= (pinfo->srcport > pinfo->destport) ? 1 : -1;
}
if (direction >= 0) {
udpd->fwd=&(udpd->flow1);
udpd->rev=&(udpd->flow2);
} else {
udpd->fwd=&(udpd->flow2);
udpd->rev=&(udpd->flow1);
}
return udpd;
}
static const char* udp_conv_get_filter_type(conv_item_t* conv, conv_filter_type_e filter)
{
if (filter == CONV_FT_SRC_PORT)
return "udp.srcport";
if (filter == CONV_FT_DST_PORT)
return "udp.dstport";
if (filter == CONV_FT_ANY_PORT)
return "udp.port";
if(!conv) {
return CONV_FILTER_INVALID;
}
if (filter == CONV_FT_SRC_ADDRESS) {
if (conv->src_address.type == AT_IPv4)
return "ip.src";
if (conv->src_address.type == AT_IPv6)
return "ipv6.src";
}
if (filter == CONV_FT_DST_ADDRESS) {
if (conv->dst_address.type == AT_IPv4)
return "ip.dst";
if (conv->dst_address.type == AT_IPv6)
return "ipv6.dst";
}
if (filter == CONV_FT_ANY_ADDRESS) {
if (conv->src_address.type == AT_IPv4)
return "ip.addr";
if (conv->src_address.type == AT_IPv6)
return "ipv6.addr";
}
return CONV_FILTER_INVALID;
}
static ct_dissector_info_t udp_ct_dissector_info = {&udp_conv_get_filter_type};
static tap_packet_status
udpip_conversation_packet(void *pct, packet_info *pinfo, epan_dissect_t *edt _U_, const void *vip)
{
conv_hash_t *hash = (conv_hash_t*) pct;
const e_udphdr *udphdr=(const e_udphdr *)vip;
add_conversation_table_data_with_conv_id(hash, &udphdr->ip_src, &udphdr->ip_dst, udphdr->uh_sport, udphdr->uh_dport, (conv_id_t) udphdr->uh_stream, 1, pinfo->fd->pkt_len, &pinfo->rel_ts, &pinfo->abs_ts, &udp_ct_dissector_info, ENDPOINT_UDP);
return TAP_PACKET_REDRAW;
}
static const char* udp_host_get_filter_type(hostlist_talker_t* host, conv_filter_type_e filter)
{
if (filter == CONV_FT_SRC_PORT)
return "udp.srcport";
if (filter == CONV_FT_DST_PORT)
return "udp.dstport";
if (filter == CONV_FT_ANY_PORT)
return "udp.port";
if(!host) {
return CONV_FILTER_INVALID;
}
if (filter == CONV_FT_SRC_ADDRESS) {
if (host->myaddress.type == AT_IPv4)
return "ip.src";
if (host->myaddress.type == AT_IPv6)
return "ipv6.src";
}
if (filter == CONV_FT_DST_ADDRESS) {
if (host->myaddress.type == AT_IPv4)
return "ip.dst";
if (host->myaddress.type == AT_IPv6)
return "ipv6.dst";
}
if (filter == CONV_FT_ANY_ADDRESS) {
if (host->myaddress.type == AT_IPv4)
return "ip.addr";
if (host->myaddress.type == AT_IPv6)
return "ipv6.addr";
}
return CONV_FILTER_INVALID;
}
static hostlist_dissector_info_t udp_host_dissector_info = {&udp_host_get_filter_type};
static tap_packet_status
udpip_hostlist_packet(void *pit, packet_info *pinfo, epan_dissect_t *edt _U_, const void *vip)
{
conv_hash_t *hash = (conv_hash_t*) pit;
const e_udphdr *udphdr=(const e_udphdr *)vip;
/* Take two "add" passes per packet, adding for each direction, ensures that all
packets are counted properly (even if address is sending to itself)
XXX - this could probably be done more efficiently inside hostlist_table */
add_hostlist_table_data(hash, &udphdr->ip_src, udphdr->uh_sport, TRUE, 1, pinfo->fd->pkt_len, &udp_host_dissector_info, ENDPOINT_UDP);
add_hostlist_table_data(hash, &udphdr->ip_dst, udphdr->uh_dport, FALSE, 1, pinfo->fd->pkt_len, &udp_host_dissector_info, ENDPOINT_UDP);
return TAP_PACKET_REDRAW;
}
static gboolean
udp_filter_valid(packet_info *pinfo)
{
return proto_is_frame_protocol(pinfo->layers, "udp");
}
static gchar*
udp_build_filter(packet_info *pinfo)
{
if( pinfo->net_src.type == AT_IPv4 && pinfo->net_dst.type == AT_IPv4 ) {
/* UDP over IPv4 */
return g_strdup_printf("(ip.addr eq %s and ip.addr eq %s) and (udp.port eq %d and udp.port eq %d)",
address_to_str(pinfo->pool, &pinfo->net_src),
address_to_str(pinfo->pool, &pinfo->net_dst),
pinfo->srcport, pinfo->destport );
}
if( pinfo->net_src.type == AT_IPv6 && pinfo->net_dst.type == AT_IPv6 ) {
/* UDP over IPv6 */
return g_strdup_printf("(ipv6.addr eq %s and ipv6.addr eq %s) and (udp.port eq %d and udp.port eq %d)",
address_to_str(pinfo->pool, &pinfo->net_src),
address_to_str(pinfo->pool, &pinfo->net_dst),
pinfo->srcport, pinfo->destport );
}
return NULL;
}
static gchar *udp_follow_conv_filter(packet_info *pinfo, guint *stream, guint *sub_stream _U_)
{
conversation_t *conv;
struct udp_analysis *udpd;
if( ((pinfo->net_src.type == AT_IPv4 && pinfo->net_dst.type == AT_IPv4) ||
(pinfo->net_src.type == AT_IPv6 && pinfo->net_dst.type == AT_IPv6))
&& (conv=find_conversation_pinfo(pinfo, 0)) != NULL )
{
/* UDP over IPv4/6 */
udpd=get_udp_conversation_data(conv, pinfo);
if (udpd == NULL)
return NULL;
*stream = udpd->stream;
return g_strdup_printf("udp.stream eq %u", udpd->stream);
}
return NULL;
}
static gchar *udp_follow_index_filter(guint stream, guint sub_stream _U_)
{
return g_strdup_printf("udp.stream eq %u", stream);
}
static gchar *udp_follow_address_filter(address *src_addr, address *dst_addr, int src_port, int dst_port)
{
const gchar *ip_version = src_addr->type == AT_IPv6 ? "v6" : "";
gchar src_addr_str[WS_INET6_ADDRSTRLEN];
gchar dst_addr_str[WS_INET6_ADDRSTRLEN];
address_to_str_buf(src_addr, src_addr_str, sizeof(src_addr_str));
address_to_str_buf(dst_addr, dst_addr_str, sizeof(dst_addr_str));
return g_strdup_printf("((ip%s.src eq %s and udp.srcport eq %d) and "
"(ip%s.dst eq %s and udp.dstport eq %d))"
" or "
"((ip%s.src eq %s and udp.srcport eq %d) and "
"(ip%s.dst eq %s and udp.dstport eq %d))",
ip_version, src_addr_str, src_port,
ip_version, dst_addr_str, dst_port,
ip_version, dst_addr_str, dst_port,
ip_version, src_addr_str, src_port);
}
/* Attach process info to a flow */
/* XXX - We depend on the UDP dissector finding the conversation first */
void
add_udp_process_info(guint32 frame_num, address *local_addr, address *remote_addr, guint16 local_port, guint16 remote_port, guint32 uid, guint32 pid, gchar *username, gchar *command) {
conversation_t *conv;
struct udp_analysis *udpd;
udp_flow_t *flow = NULL;
if (!udp_process_info) {
return;
}
conv = find_conversation(frame_num, local_addr, remote_addr, ENDPOINT_UDP, local_port, remote_port, 0);
if (!conv) {
return;
}
udpd = (struct udp_analysis *)conversation_get_proto_data(conv, hfi_udp->id);
if (!udpd) {
return;
}
if ((cmp_address(local_addr, conversation_key_addr1(conv->key_ptr)) == 0) && (local_port == conversation_key_port1(conv->key_ptr))) {
flow = &udpd->flow1;
} else if ((cmp_address(remote_addr, conversation_key_addr1(conv->key_ptr)) == 0) && (remote_port == conversation_key_port1(conv->key_ptr))) {
flow = &udpd->flow2;
}
if (!flow || flow->command) {
return;
}
flow->process_uid = uid;
flow->process_pid = pid;
flow->username = wmem_strdup(wmem_file_scope(), username);
flow->command = wmem_strdup(wmem_file_scope(), command);
}
/* Return the current stream count */
guint32 get_udp_stream_count(void)
{
return udp_stream_count;
}
static void
handle_export_pdu_dissection_table(packet_info *pinfo, tvbuff_t *tvb, guint32 port)
{
if (have_tap_listener(exported_pdu_tap)) {
exp_pdu_data_item_t exp_pdu_data_table_value = {exp_pdu_data_dissector_table_num_value_size, exp_pdu_data_dissector_table_num_value_populate_data, NULL};
const exp_pdu_data_item_t *udp_exp_pdu_items[] = {
&exp_pdu_data_src_ip,
&exp_pdu_data_dst_ip,
&exp_pdu_data_port_type,
&exp_pdu_data_src_port,
&exp_pdu_data_dst_port,
&exp_pdu_data_orig_frame_num,
&exp_pdu_data_table_value,
NULL
};
exp_pdu_data_t *exp_pdu_data;
exp_pdu_data_table_value.data = GUINT_TO_POINTER(port);
exp_pdu_data = export_pdu_create_tags(pinfo, "udp.port", EXP_PDU_TAG_DISSECTOR_TABLE_NAME, udp_exp_pdu_items);
exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
exp_pdu_data->pdu_tvb = tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
}
static void
handle_export_pdu_heuristic(packet_info *pinfo, tvbuff_t *tvb, heur_dtbl_entry_t *hdtbl_entry)
{
exp_pdu_data_t *exp_pdu_data = NULL;
if (have_tap_listener(exported_pdu_tap)) {
if ((!hdtbl_entry->enabled) ||
(hdtbl_entry->protocol != NULL && !proto_is_protocol_enabled(hdtbl_entry->protocol))) {
exp_pdu_data = export_pdu_create_common_tags(pinfo, "data", EXP_PDU_TAG_PROTO_NAME);
} else if (hdtbl_entry->protocol != NULL) {
exp_pdu_data = export_pdu_create_common_tags(pinfo, hdtbl_entry->short_name, EXP_PDU_TAG_HEUR_PROTO_NAME);
}
if (exp_pdu_data != NULL) {
exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
exp_pdu_data->pdu_tvb = tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
}
}
static void
handle_export_pdu_conversation(packet_info *pinfo, tvbuff_t *tvb, int uh_dport, int uh_sport)
{
if (have_tap_listener(exported_pdu_tap)) {
conversation_t *conversation = find_conversation(pinfo->num, &pinfo->dst, &pinfo->src, ENDPOINT_UDP, uh_dport, uh_sport, 0);
if (conversation != NULL)
{
dissector_handle_t handle = (dissector_handle_t)wmem_tree_lookup32_le(conversation->dissector_tree, pinfo->num);
if (handle != NULL)
{
exp_pdu_data_t *exp_pdu_data = export_pdu_create_common_tags(pinfo, dissector_handle_get_dissector_name(handle), EXP_PDU_TAG_PROTO_NAME);
exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
exp_pdu_data->pdu_tvb = tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
}
}
}
void
decode_udp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
proto_tree *udp_tree, int uh_sport, int uh_dport, int uh_ulen)
{
tvbuff_t *next_tvb;
int low_port, high_port;
gint len, reported_len;
udp_p_info_t *udp_p_info;
/* Save curr_layer_num as it might be changed by subdissector */
guint8 curr_layer_num = pinfo->curr_layer_num;
heur_dtbl_entry_t *hdtbl_entry;
exp_pdu_data_t *exp_pdu_data;
proto_tree* tree = proto_tree_get_root(udp_tree);
/* populate per packet data variable */
udp_p_info = (udp_p_info_t*)p_get_proto_data(wmem_file_scope(), pinfo, hfi_udp->id, pinfo->curr_layer_num);
len = tvb_captured_length_remaining(tvb, offset);
reported_len = tvb_reported_length_remaining(tvb, offset);
if (uh_ulen != -1) {
/* This is the length from the UDP header; the payload should be cut
off at that length. (If our caller passed a value here, they
are assumed to have checked that it's >= 8, and hence >= offset.)
XXX - what if it's *greater* than the reported length? */
if ((uh_ulen - offset) < reported_len)
reported_len = uh_ulen - offset;
if (len > reported_len)
len = reported_len;
}
// proto_tree_add_item(udp_tree, &hfi_udp_payload, tvb, offset, len, ENC_NA);
proto_tree_add_bytes_format(udp_tree, &hfi_udp_payload, tvb, offset,
-1, NULL, "UDP payload (%u byte%s)", len,
plurality(len, "", "s"));
next_tvb = tvb_new_subset_length_caplen(tvb, offset, len, reported_len);
/* If the user has a "Follow UDP Stream" window loading, pass a pointer
* to the payload tvb through the tap system. */
if (have_tap_listener(udp_follow_tap))
tap_queue_packet(udp_follow_tap, pinfo, next_tvb);
if (PINFO_FD_VISITED(pinfo)) {
if (udp_p_info && udp_p_info->heur_dtbl_entry != NULL) {
call_heur_dissector_direct(udp_p_info->heur_dtbl_entry, next_tvb, pinfo, tree, NULL);
handle_export_pdu_heuristic(pinfo, next_tvb, udp_p_info->heur_dtbl_entry);
return;
}
}
/* determine if this packet is part of a conversation and call dissector */
/* for the conversation if available */
if (try_conversation_dissector(&pinfo->dst, &pinfo->src, ENDPOINT_UDP,
uh_dport, uh_sport, next_tvb, pinfo, tree, NULL, NO_ADDR_B|NO_PORT_B)) {
handle_export_pdu_conversation(pinfo, next_tvb, uh_dport, uh_sport);
return;
}
if (try_heuristic_first) {
/* Do lookup with the heuristic subdissector table */
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
if (!udp_p_info) {
udp_p_info = wmem_new0(wmem_file_scope(), udp_p_info_t);
p_add_proto_data(wmem_file_scope(), pinfo, hfi_udp->id, curr_layer_num, udp_p_info);
}
udp_p_info->heur_dtbl_entry = hdtbl_entry;
handle_export_pdu_heuristic(pinfo, next_tvb, udp_p_info->heur_dtbl_entry);
return;
}
}
/* Do lookups with the subdissector table.
We try the port number with the lower value first, followed by the
port number with the higher value. This means that, for packets
where a dissector is registered for *both* port numbers:
1) we pick the same dissector for traffic going in both directions;
2) we prefer the port number that's more likely to be the right
one (as that prefers well-known ports to reserved ports);
although there is, of course, no guarantee that any such strategy
will always pick the right port number.
XXX - we ignore port numbers of 0, as some dissectors use a port
number of 0 to disable the port, and as RFC 768 says that the source
port in UDP datagrams is optional and is 0 if not used. */
if (uh_sport > uh_dport) {
low_port = uh_dport;
high_port = uh_sport;
} else {
low_port = uh_sport;
high_port = uh_dport;
}
if ((low_port != 0) &&
dissector_try_uint(udp_dissector_table, low_port, next_tvb, pinfo, tree)) {
handle_export_pdu_dissection_table(pinfo, next_tvb, low_port);
return;
}
if ((high_port != 0) &&
dissector_try_uint(udp_dissector_table, high_port, next_tvb, pinfo, tree)) {
handle_export_pdu_dissection_table(pinfo, next_tvb, high_port);
return;
}
if (!try_heuristic_first) {
/* Do lookup with the heuristic subdissector table */
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
if (!udp_p_info) {
udp_p_info = wmem_new0(wmem_file_scope(), udp_p_info_t);
p_add_proto_data(wmem_file_scope(), pinfo, hfi_udp->id, curr_layer_num, udp_p_info);
}
udp_p_info->heur_dtbl_entry = hdtbl_entry;
handle_export_pdu_heuristic(pinfo, next_tvb, udp_p_info->heur_dtbl_entry);
return;
}
}
call_data_dissector(next_tvb, pinfo, tree);
if (have_tap_listener(exported_pdu_tap)) {
exp_pdu_data = export_pdu_create_common_tags(pinfo, "data", EXP_PDU_TAG_PROTO_NAME);
exp_pdu_data->tvb_captured_length = tvb_captured_length(next_tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(next_tvb);
exp_pdu_data->pdu_tvb = next_tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
}
int
udp_dissect_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
guint fixed_len, gboolean (*heuristic_check)(packet_info *, tvbuff_t *, int, void*),
guint (*get_pdu_len)(packet_info *, tvbuff_t *, int, void*),
dissector_t dissect_pdu, void* dissector_data)
{
volatile int offset = 0;
int offset_before;
guint captured_length_remaining;
volatile guint plen;
guint length;
tvbuff_t *next_tvb;
proto_item *item=NULL;
const char *saved_proto;
guint8 curr_layer_num;
wmem_list_frame_t *frame;
while (tvb_reported_length_remaining(tvb, offset) > 0) {
/*
* We use "tvb_ensure_captured_length_remaining()" to make
* sure there actually *is* data remaining. The protocol
* we're handling could conceivably consists of a sequence of
* fixed-length PDUs, and therefore the "get_pdu_len" routine
* might not actually fetch anything from the tvbuff, and thus
* might not cause an exception to be thrown if we've run past
* the end of the tvbuff.
*
* This means we're guaranteed that "captured_length_remaining" is positive.
*/
captured_length_remaining = tvb_ensure_captured_length_remaining(tvb, offset);
/*
* If there is a heuristic function, check it
*/
if ((heuristic_check != NULL) &&
((*heuristic_check)(pinfo, tvb, offset, dissector_data) == FALSE)) {
return offset;
}
/*
* Get the length of the PDU.
*/
plen = (*get_pdu_len)(pinfo, tvb, offset, dissector_data);
if (plen == 0) {
/*
* Either protocol has variable length (which isn't supposed by UDP)
* or packet doesn't belong to protocol
*/
return offset;
}
if (plen < fixed_len) {
/*
* Either:
*
* 1) the length value extracted from the fixed-length portion
* doesn't include the fixed-length portion's length, and
* was so large that, when the fixed-length portion's
* length was added to it, the total length overflowed;
*
* 2) the length value extracted from the fixed-length portion
* includes the fixed-length portion's length, and the value
* was less than the fixed-length portion's length, i.e. it
* was bogus.
*
* Report this as a bounds error.
*/
show_reported_bounds_error(tvb, pinfo, tree);
return offset;
}
curr_layer_num = pinfo->curr_layer_num-1;
frame = wmem_list_frame_prev(wmem_list_tail(pinfo->layers));
while (frame && (hfi_udp->id != (gint) GPOINTER_TO_UINT(wmem_list_frame_data(frame)))) {
frame = wmem_list_frame_prev(frame);
curr_layer_num--;
}
/*
* Display the PDU length as a field
*/
item=proto_tree_add_uint((proto_tree *)p_get_proto_data(pinfo->pool, pinfo, hfi_udp->id, curr_layer_num),
&hfi_udp_pdu_size,
tvb, offset, plen, plen);
proto_item_set_generated(item);
/*
* Construct a tvbuff containing the amount of the payload we have
* available. Make its reported length the amount of data in the PDU.
*/
length = captured_length_remaining;
if (length > plen)
length = plen;
next_tvb = tvb_new_subset_length_caplen(tvb, offset, length, plen);
/*
* Dissect the PDU.
*
* If it gets an error that means there's no point in
* dissecting any more PDUs, rethrow the exception in
* question.
*
* If it gets any other error, report it and continue, as that
* means that PDU got an error, but that doesn't mean we should
* stop dissecting PDUs within this frame or chunk of reassembled
* data.
*/
saved_proto = pinfo->current_proto;
TRY {
(*dissect_pdu)(next_tvb, pinfo, tree, dissector_data);
}
CATCH_NONFATAL_ERRORS {
/* Restore the private_data structure in case one of the
* called dissectors modified it (and, due to the exception,
* was unable to restore it).
*/
show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
/*
* Restore the saved protocol as well; we do this after
* show_exception(), so that the "Malformed packet" indication
* shows the protocol for which dissection failed.
*/
pinfo->current_proto = saved_proto;
}
ENDTRY;
/*
* Step to the next PDU.
* Make sure we don't overflow.
*/
offset_before = offset;
offset += plen;
if (offset <= offset_before)
break;
}
return offset;
}
static gboolean
capture_udp(const guchar *pd _U_, int offset _U_, int len _U_, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_)
{
guint16 src_port, dst_port, low_port, high_port;
if (!BYTES_ARE_IN_FRAME(offset, len, 4))
return FALSE;
capture_dissector_increment_count(cpinfo, hfi_udp->id);
src_port = pntoh16(&pd[offset]);
dst_port = pntoh16(&pd[offset+2]);
if (src_port > dst_port) {
low_port = dst_port;
high_port = src_port;
} else {
low_port = src_port;
high_port = dst_port;
}
if (low_port != 0 &&
try_capture_dissector("udp.port", low_port, pd, offset+20, len, cpinfo, pseudo_header))
return TRUE;
if (high_port != 0 &&
try_capture_dissector("udp.port", high_port, pd, offset+20, len, cpinfo, pseudo_header))
return TRUE;
/* We've at least identified one type of packet, so this shouldn't be "other" */
return TRUE;
}
/* Calculate the timestamps relative to this conversation */
static void
udp_compute_timestamps(packet_info *pinfo, struct udp_analysis *udp_data, int proto)
{
if (!udp_data)
return;
/* get per packet date for UDP/UDP-Lite based on protocol id */
udp_p_info_t *udp_per_packet_data = (udp_p_info_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto, pinfo->curr_layer_num);
if(!udp_per_packet_data) {
udp_per_packet_data = wmem_new0(wmem_file_scope(), udp_p_info_t);
p_add_proto_data(wmem_file_scope(), pinfo, proto, pinfo->curr_layer_num, udp_per_packet_data);
}
nstime_delta(&udp_per_packet_data->ts_delta, &pinfo->abs_ts, &udp_data->ts_prev);
udp_per_packet_data->ts_delta_valid = TRUE;
udp_data->ts_prev = pinfo->abs_ts;
}
/* Add a subtree with the timestamps relative to this conversation */
static void
udp_print_timestamps(packet_info *pinfo, tvbuff_t *tvb, proto_tree *parent_tree, struct udp_analysis *udp_data, int proto)
{
proto_item *item;
proto_tree *tree;
nstime_t ts;
if (!udp_data)
return;
/* get per packet date for UDP/UDP-Lite based on protocol id */
udp_p_info_t *udp_per_packet_data = (udp_p_info_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto, pinfo->curr_layer_num);
tree = proto_tree_add_subtree(parent_tree, tvb, 0, 0, ett_udp_timestamps, &item, "Timestamps");
proto_item_set_generated(item);
nstime_delta(&ts, &pinfo->abs_ts, &udp_data->ts_first);
item = proto_tree_add_time(tree, &hfi_udp_ts_relative, tvb, 0, 0, &ts);
proto_item_set_generated(item);
if (udp_per_packet_data && udp_per_packet_data->ts_delta_valid) {
item = proto_tree_add_time(tree, &hfi_udp_ts_delta, tvb, 0, 0,
&udp_per_packet_data->ts_delta);
proto_item_set_generated(item);
}
}
static void
udp_handle_timestamps(packet_info *pinfo, tvbuff_t *tvb, proto_tree *tree, struct udp_analysis *udp_data, guint32 ip_proto)
{
int proto_id = (ip_proto == IP_PROTO_UDP ? hfi_udp->id : hfi_udplite->id);
/*
* Calculate the timestamps relative to this conversation (but only on the
* first run when frames are accessed sequentially)
*/
if (!PINFO_FD_VISITED(pinfo))
udp_compute_timestamps(pinfo, udp_data, proto_id);
/* handle conversation timestamps */
udp_print_timestamps(pinfo, tvb, tree, udp_data, proto_id);
}
static void
dissect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 ip_proto)
{
proto_tree *udp_tree = NULL;
proto_item *ti, *item, *hidden_item, *calc_item;
proto_item *src_port_item, *dst_port_item, *len_cov_item;
guint len;
guint reported_len;
vec_t cksum_vec[4];
guint32 phdr[2];
guint16 computed_cksum;
int offset = 0;
e_udphdr *udph;
proto_tree *checksum_tree;
conversation_t *conv = NULL;
struct udp_analysis *udpd = NULL;
proto_tree *process_tree;
gboolean udp_jumbogram = FALSE;
udph = wmem_new0(wmem_packet_scope(), e_udphdr);
udph->uh_sport = tvb_get_ntohs(tvb, offset);
udph->uh_dport = tvb_get_ntohs(tvb, offset + 2);
copy_address_shallow(&udph->ip_src, &pinfo->src);
copy_address_shallow(&udph->ip_dst, &pinfo->dst);
col_set_str(pinfo->cinfo, COL_PROTOCOL, (ip_proto == IP_PROTO_UDP) ? "UDP" : "UDP-Lite");
col_clear(pinfo->cinfo, COL_INFO);
col_append_ports(pinfo->cinfo, COL_INFO, PT_UDP, udph->uh_sport, udph->uh_dport);
reported_len = tvb_reported_length(tvb);
len = tvb_captured_length(tvb);
ti = proto_tree_add_item(tree, (ip_proto == IP_PROTO_UDP) ? hfi_udp : hfi_udplite, tvb, offset, 8, ENC_NA);
if (udp_summary_in_tree) {
proto_item_append_text(ti, ", Src Port: %s, Dst Port: %s",
port_with_resolution_to_str(wmem_packet_scope(), PT_UDP, udph->uh_sport),
port_with_resolution_to_str(wmem_packet_scope(), PT_UDP, udph->uh_dport));
}
udp_tree = proto_item_add_subtree(ti, ett_udp);
p_add_proto_data(pinfo->pool, pinfo, hfi_udp->id, pinfo->curr_layer_num, udp_tree);
src_port_item = proto_tree_add_item(udp_tree, &hfi_udp_srcport, tvb, offset, 2, ENC_BIG_ENDIAN);
dst_port_item = proto_tree_add_item(udp_tree, &hfi_udp_dstport, tvb, offset + 2, 2, ENC_BIG_ENDIAN);
p_add_proto_data(pinfo->pool, pinfo, hfi_udp_srcport.id, pinfo->curr_layer_num, GUINT_TO_POINTER(udph->uh_sport));
p_add_proto_data(pinfo->pool, pinfo, hfi_udp_dstport.id, pinfo->curr_layer_num, GUINT_TO_POINTER(udph->uh_dport));
hidden_item = proto_tree_add_item(udp_tree, &hfi_udp_port, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_item_set_hidden(hidden_item);
hidden_item = proto_tree_add_item(udp_tree, &hfi_udp_port, tvb, offset + 2, 2, ENC_BIG_ENDIAN);
proto_item_set_hidden(hidden_item);
/* The beginning port number, 32768 + 666 (33434), is from LBL's traceroute.c source code and this code
* further assumes that 3 attempts are made per hop */
if ((udph->uh_sport > (32768 + 666)) && (udph->uh_sport <= (32768 + 666 + 30))) {
expert_add_info_format(pinfo, src_port_item, &ei_udp_possible_traceroute, "Possible traceroute: hop #%u, attempt #%u",
((udph->uh_sport - 32768 - 666 - 1) / 3) + 1,
((udph->uh_sport - 32768 - 666 - 1) % 3) + 1);
}
if ((udph->uh_dport > (32768 + 666)) && (udph->uh_dport <= (32768 + 666 + 30))) {
expert_add_info_format(pinfo, dst_port_item, &ei_udp_possible_traceroute, "Possible traceroute: hop #%u, attempt #%u",
((udph->uh_dport - 32768 - 666 - 1) / 3) + 1,
((udph->uh_dport - 32768 - 666 - 1) % 3) + 1);
}
udph->uh_ulen = udph->uh_sum_cov = tvb_get_ntohs(tvb, offset + 4);
if (ip_proto == IP_PROTO_UDP) {
len_cov_item = proto_tree_add_item(udp_tree, &hfi_udp_length, tvb, offset + 4, 2, ENC_BIG_ENDIAN);
if (udph->uh_ulen == 0 && pinfo->src.type == AT_IPv6) {
/* RFC 2675 (section 4) - UDP Jumbograms */
udph->uh_ulen = udph->uh_sum_cov = reported_len;
udp_jumbogram = TRUE;
}
if (udph->uh_ulen < 8) {
/* Bogus length - it includes the header, so it must be >= 8. */
proto_item_append_text(len_cov_item, " (bogus, must be >= 8)");
expert_add_info_format(pinfo, len_cov_item, &ei_udp_length_bad, "Bad length value %u < 8", udph->uh_ulen);
col_append_fstr(pinfo->cinfo, COL_INFO, " [BAD UDP LENGTH %u < 8]", udph->uh_ulen);
return;
}
if ((udph->uh_ulen > reported_len) && (!pinfo->fragmented) && (!pinfo->flags.in_error_pkt)) {
/* Bogus length - it goes past the end of the IP payload */
proto_item_append_text(len_cov_item, " (bogus, payload length %u)", reported_len);
expert_add_info_format(pinfo, len_cov_item, &ei_udp_length_bad, "Bad length value %u > IP payload length", udph->uh_ulen);
col_append_fstr(pinfo->cinfo, COL_INFO, " [BAD UDP LENGTH %u > IP PAYLOAD LENGTH]", udph->uh_ulen);
/*return;*/
}
if (udp_jumbogram && (udph->uh_ulen < 65536)) {
expert_add_info(pinfo, len_cov_item, &ei_udp_length_bad_zero);
}
} else {
len_cov_item = proto_tree_add_item(udp_tree, &hfi_udplite_checksum_coverage, tvb, offset + 4, 2, ENC_BIG_ENDIAN);
udph->uh_ulen = reported_len;
if (udph->uh_sum_cov == 0) {
udph->uh_sum_cov = reported_len;
}
item = proto_tree_add_uint(udp_tree, &hfi_udp_length, tvb, offset + 4, 0, udph->uh_ulen);
proto_item_set_generated(item);
if ((udph->uh_sum_cov < 8) || (udph->uh_sum_cov > udph->uh_ulen)) {
/* Bogus coverage - it includes the header, so it must be >= 8, and no larger then the IP payload size. */
proto_item_append_text(len_cov_item, " (bogus, must be >= 8 and <= %u)", udph->uh_ulen);
expert_add_info_format(pinfo, len_cov_item, &ei_udplite_checksum_coverage_bad, "Bad checksum coverage length value %u < 8 or > %u",
udph->uh_sum_cov, udph->uh_ulen);
col_append_fstr(pinfo->cinfo, COL_INFO, " [BAD LIGHTWEIGHT UDP CHECKSUM COVERAGE LENGTH %u < 8 or > %u]",
udph->uh_sum_cov, udph->uh_ulen);
if (!udplite_ignore_checksum_coverage) {
return;
}
}
}
col_append_str_uint(pinfo->cinfo, COL_INFO, "Len", udph->uh_ulen - 8, " "); /* Payload length */
if (udp_jumbogram)
col_append_str(pinfo->cinfo, COL_INFO, " [Jumbogram]");
udph->uh_sum = tvb_get_ntohs(tvb, offset + 6);
if (udph->uh_sum == 0) {
/* No checksum supplied in the packet. */
if (((ip_proto == IP_PROTO_UDP) && (pinfo->src.type == AT_IPv4)) || pinfo->flags.in_error_pkt) {
proto_tree_add_checksum(udp_tree, tvb, offset + 6, &hfi_udp_checksum, hfi_udp_checksum_status.id, &ei_udp_checksum_bad,
pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NOT_PRESENT);
} else {
item = proto_tree_add_uint_format_value(udp_tree, &hfi_udp_checksum, tvb, offset + 6, 2, 0, "0 (Illegal)%s", "");
checksum_tree = proto_item_add_subtree(item, ett_udp_checksum);
expert_add_info(pinfo, item, &ei_udp_checksum_zero);
col_append_str(pinfo->cinfo, COL_INFO, " [ILLEGAL CHECKSUM (0)]");
/* XXX - What should this special status be? */
item = proto_tree_add_uint(checksum_tree, &hfi_udp_checksum_status, tvb,
offset + 6, 0, 4);
proto_item_set_generated(item);
}
} else if (!pinfo->fragmented && (len >= reported_len) &&
(len >= udph->uh_sum_cov) && (reported_len >= udph->uh_sum_cov) &&
(udph->uh_sum_cov >= 8)) {
/* The packet isn't part of a fragmented datagram and isn't
truncated, so we can checksum it.
XXX - make a bigger scatter-gather list once we do fragment
reassembly? */
if (((ip_proto == IP_PROTO_UDP) && udp_check_checksum) ||
((ip_proto == IP_PROTO_UDPLITE) && udplite_check_checksum)) {
/* Set up the fields of the pseudo-header. */
SET_CKSUM_VEC_PTR(cksum_vec[0], (const guint8 *)pinfo->src.data, pinfo->src.len);
SET_CKSUM_VEC_PTR(cksum_vec[1], (const guint8 *)pinfo->dst.data, pinfo->dst.len);
switch (pinfo->src.type) {
case AT_IPv4:
if (ip_proto == IP_PROTO_UDP)
phdr[0] = g_htonl((ip_proto<<16) | udph->uh_ulen);
else
phdr[0] = g_htonl((ip_proto<<16) | reported_len);
SET_CKSUM_VEC_PTR(cksum_vec[2], (const guint8 *)&phdr, 4);
break;
case AT_IPv6:
if (ip_proto == IP_PROTO_UDP)
phdr[0] = g_htonl(udph->uh_ulen);
else
phdr[0] = g_htonl(reported_len);
phdr[1] = g_htonl(ip_proto);
SET_CKSUM_VEC_PTR(cksum_vec[2], (const guint8 *)&phdr, 8);
break;
default:
/* UDP runs only atop IPv4 and IPv6.... */
DISSECTOR_ASSERT_NOT_REACHED();
break;
}
SET_CKSUM_VEC_TVB(cksum_vec[3], tvb, offset, udph->uh_sum_cov);
computed_cksum = in_cksum(&cksum_vec[0], 4);
item = proto_tree_add_checksum(udp_tree, tvb, offset + 6, &hfi_udp_checksum, hfi_udp_checksum_status.id, &ei_udp_checksum_bad,
pinfo, computed_cksum, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
checksum_tree = proto_item_add_subtree(item, ett_udp_checksum);
/*
* in_cksum() should never return 0xFFFF here, because, to quote
* RFC 1624 section 3 "Discussion":
*
* In one's complement, there are two representations of
* zero: the all zero and the all one bit values, often
* referred to as +0 and -0. One's complement addition
* of non-zero inputs can produce -0 as a result, but
* never +0. Since there is guaranteed to be at least
* one non-zero field in the IP header, and the checksum
* field in the protocol header is the complement of the
* sum, the checksum field can never contain ~(+0), which
* is -0 (0xFFFF). It can, however, contain ~(-0), which
* is +0 (0x0000).
*
* RFC 1624 is discussing the checksum of the *IPv4* header,
* where the "version" field is 4, ensuring that, in a valid
* IPv4 header, there is at least one non-zero field, but it
* also applies to a UDP datagram, because the length includes
* the length of the UDP header, so at least one field in a UDP
* datagram is non-zero.
*
* in_cksum() returns the negation of the one's-complement
* sum of all the data handed to it, and that data won't be
* all zero, so the sum won't be 0 (+0), and thus the negation
* won't be -0, i.e. won't be 0xFFFF.
*/
if (computed_cksum != 0) {
proto_item_append_text(item, " (maybe caused by \"UDP checksum offload\"?)");
col_append_str(pinfo->cinfo, COL_INFO, " [UDP CHECKSUM INCORRECT]");
calc_item = proto_tree_add_uint(checksum_tree, &hfi_udp_checksum_calculated,
tvb, offset + 6, 2, in_cksum_shouldbe(udph->uh_sum, computed_cksum));
} else {
calc_item = proto_tree_add_uint(checksum_tree, &hfi_udp_checksum_calculated,
tvb, offset + 6, 2, udph->uh_sum);
}
proto_item_set_generated(calc_item);
} else {
proto_tree_add_checksum(udp_tree, tvb, offset + 6, &hfi_udp_checksum, hfi_udp_checksum_status.id, &ei_udp_checksum_bad, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
} else {
proto_tree_add_checksum(udp_tree, tvb, offset + 6, &hfi_udp_checksum, hfi_udp_checksum_status.id, &ei_udp_checksum_bad, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
/* Skip over header */
offset += 8;
pinfo->ptype = PT_UDP;
pinfo->srcport = udph->uh_sport;
pinfo->destport = udph->uh_dport;
/* find(or create if needed) the conversation for this udp session */
conv = find_or_create_conversation(pinfo);
udpd = get_udp_conversation_data(conv, pinfo);
if (udpd) {
item = proto_tree_add_uint(udp_tree, &hfi_udp_stream, tvb, offset, 0, udpd->stream);
proto_item_set_generated(item);
/* Copy the stream index into the header as well to make it available
* to tap listeners.
*/
udph->uh_stream = udpd->stream;
}
tap_queue_packet(udp_tap, pinfo, udph);
if (udpd && ((udpd->fwd && udpd->fwd->command) || (udpd->rev && udpd->rev->command))) {
process_tree = proto_tree_add_subtree(udp_tree, tvb, offset, 0, ett_udp_process_info, &ti, "Process Information");
proto_item_set_generated(ti);
if (udpd->fwd && udpd->fwd->command) {
proto_tree_add_uint(process_tree, &hfi_udp_proc_dst_uid, tvb, 0, 0, udpd->fwd->process_uid);
proto_tree_add_uint(process_tree, &hfi_udp_proc_dst_pid, tvb, 0, 0, udpd->fwd->process_pid);
proto_tree_add_string(process_tree, &hfi_udp_proc_dst_uname, tvb, 0, 0, udpd->fwd->username);
proto_tree_add_string(process_tree, &hfi_udp_proc_dst_cmd, tvb, 0, 0, udpd->fwd->command);
}
if (udpd->rev->command) {
proto_tree_add_uint(process_tree, &hfi_udp_proc_src_uid, tvb, 0, 0, udpd->rev->process_uid);
proto_tree_add_uint(process_tree, &hfi_udp_proc_src_pid, tvb, 0, 0, udpd->rev->process_pid);
proto_tree_add_string(process_tree, &hfi_udp_proc_src_uname, tvb, 0, 0, udpd->rev->username);
proto_tree_add_string(process_tree, &hfi_udp_proc_src_cmd, tvb, 0, 0, udpd->rev->command);
}
}
if (udph->uh_ulen == 8) {
/* Empty UDP payload, nothing left to do. */
return;
}
/* Do we need to calculate timestamps relative to the udp-stream? */
/* Different boolean preferences have to be checked. */
/* If the protocol is UDP then the UDP preference */
if (!pinfo->flags.in_error_pkt &&
((ip_proto == IP_PROTO_UDP && udp_calculate_ts)
/* Otherwise the UDP-Lite preference */
|| (ip_proto == IP_PROTO_UDPLITE && udplite_calculate_ts))) {
udp_handle_timestamps(pinfo, tvb, udp_tree, udpd, ip_proto);
}
/*
* Call sub-dissectors.
*
* XXX - should we do this if this is included in an error packet?
* It might be nice to see the details of the packet that caused the
* ICMP error, but it might not be nice to have the dissector update
* state based on it.
* Also, we probably don't want to run UDP taps on those packets.
*
* We definitely don't want to do it for an error packet if there's
* nothing left in the packet.
*/
if (!pinfo->flags.in_error_pkt || (tvb_captured_length_remaining(tvb, offset) > 0))
decode_udp_ports(tvb, offset, pinfo, udp_tree, udph->uh_sport, udph->uh_dport, udph->uh_ulen);
}
static int
dissect_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
dissect(tvb, pinfo, tree, IP_PROTO_UDP);
return tvb_captured_length(tvb);
}
static int
dissect_udplite(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
dissect(tvb, pinfo, tree, IP_PROTO_UDPLITE);
return tvb_captured_length(tvb);
}
static void
udp_init(void)
{
udp_stream_count = 0;
}
void
proto_register_udp(void)
{
module_t *udp_module;
module_t *udplite_module;
expert_module_t* expert_udp;
#ifndef HAVE_HFI_SECTION_INIT
static header_field_info *hfi[] = {
&hfi_udp_srcport,
&hfi_udp_dstport,
&hfi_udp_port,
&hfi_udp_stream,
&hfi_udp_length,
&hfi_udp_checksum,
&hfi_udp_checksum_calculated,
&hfi_udp_checksum_status,
&hfi_udp_proc_src_uid,
&hfi_udp_proc_src_pid,
&hfi_udp_proc_src_uname,
&hfi_udp_proc_src_cmd,
&hfi_udp_proc_dst_uid,
&hfi_udp_proc_dst_pid,
&hfi_udp_proc_dst_uname,
&hfi_udp_proc_dst_cmd,
&hfi_udp_pdu_size,
&hfi_udp_ts_relative,
&hfi_udp_ts_delta,
&hfi_udp_payload
};
static header_field_info *hfi_lite[] = {
&hfi_udplite_checksum_coverage,
};
#endif
static gint *ett[] = {
&ett_udp,
&ett_udp_checksum,
&ett_udp_process_info,
&ett_udp_timestamps
};
static ei_register_info ei[] = {
{ &ei_udp_possible_traceroute, { "udp.possible_traceroute", PI_SEQUENCE, PI_CHAT, "Possible traceroute", EXPFILL }},
{ &ei_udp_length_bad, { "udp.length.bad", PI_MALFORMED, PI_ERROR, "Bad length value", EXPFILL }},
{ &ei_udplite_checksum_coverage_bad, { "udplite.checksum_coverage.bad", PI_MALFORMED, PI_ERROR, "Bad checksum coverage length value", EXPFILL }},
{ &ei_udp_checksum_zero, { "udp.checksum.zero", PI_CHECKSUM, PI_ERROR, "Illegal Checksum value (0)", EXPFILL }},
{ &ei_udp_checksum_bad, { "udp.checksum.bad", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
{ &ei_udp_length_bad_zero, { "udp.length.bad_zero", PI_PROTOCOL, PI_WARN, "Length is zero but payload < 65536", EXPFILL }},
};
static build_valid_func udp_da_src_values[1] = {udp_src_value};
static build_valid_func udp_da_dst_values[1] = {udp_dst_value};
static build_valid_func udp_da_both_values[2] = {udp_src_value, udp_dst_value};
static decode_as_value_t udp_da_values[3] = {{udp_src_prompt, 1, udp_da_src_values}, {udp_dst_prompt, 1, udp_da_dst_values}, {udp_both_prompt, 2, udp_da_both_values}};
static decode_as_t udp_da = {"udp", "udp.port", 3, 2, udp_da_values, "UDP", "port(s) as",
decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL};
int proto_udp, proto_udplite;
proto_udp = proto_register_protocol("User Datagram Protocol",
"UDP", "udp");
hfi_udp = proto_registrar_get_nth(proto_udp);
udp_handle = register_dissector("udp", dissect_udp, proto_udp);
expert_udp = expert_register_protocol(proto_udp);
proto_register_fields(proto_udp, hfi, array_length(hfi));
proto_udplite = proto_register_protocol("Lightweight User Datagram Protocol",
"UDP-Lite", "udplite");
udplite_handle = create_dissector_handle(dissect_udplite, proto_udplite);
hfi_udplite = proto_registrar_get_nth(proto_udplite);
proto_register_fields(proto_udplite, hfi_lite, array_length(hfi_lite));
proto_register_subtree_array(ett, array_length(ett));
expert_register_field_array(expert_udp, ei, array_length(ei));
/* subdissector code */
udp_dissector_table = register_dissector_table("udp.port",
"UDP port", proto_udp, FT_UINT16, BASE_DEC);
heur_subdissector_list = register_heur_dissector_list("udp", proto_udp);
register_capture_dissector_table("udp.port", "UDP");
/* Register configuration preferences */
udp_module = prefs_register_protocol(proto_udp, NULL);
prefs_register_bool_preference(udp_module, "summary_in_tree",
"Show UDP summary in protocol tree",
"Whether the UDP summary line should be shown in the protocol tree",
&udp_summary_in_tree);
prefs_register_bool_preference(udp_module, "try_heuristic_first",
"Try heuristic sub-dissectors first",
"Try to decode a packet using an heuristic sub-dissector"
" before using a sub-dissector registered to a specific port",
&try_heuristic_first);
prefs_register_bool_preference(udp_module, "check_checksum",
"Validate the UDP checksum if possible",
"Whether to validate the UDP checksum",
&udp_check_checksum);
prefs_register_bool_preference(udp_module, "process_info",
"Collect process flow information",
"Collect process flow information from IPFIX",
&udp_process_info);
prefs_register_bool_preference(udp_module, "calculate_timestamps",
"Calculate conversation timestamps",
"Calculate timestamps relative to the first frame and the previous frame in the udp conversation",
&udp_calculate_ts);
udplite_module = prefs_register_protocol(proto_udplite, NULL);
prefs_register_bool_preference(udplite_module, "ignore_checksum_coverage",
"Ignore UDP-Lite checksum coverage",
"Ignore an invalid checksum coverage field and continue dissection",
&udplite_ignore_checksum_coverage);
prefs_register_bool_preference(udplite_module, "check_checksum",
"Validate the UDP-Lite checksum if possible",
"Whether to validate the UDP-Lite checksum",
&udplite_check_checksum);
prefs_register_bool_preference(udplite_module, "calculate_timestamps",
"Calculate conversation timestamps",
"Calculate timestamps relative to the first frame and the previous frame in the udp-lite conversation",
&udplite_calculate_ts);
register_decode_as(&udp_da);
register_conversation_table(proto_udp, FALSE, udpip_conversation_packet, udpip_hostlist_packet);
register_conversation_filter("udp", "UDP", udp_filter_valid, udp_build_filter);
register_follow_stream(proto_udp, "udp_follow", udp_follow_conv_filter, udp_follow_index_filter, udp_follow_address_filter,
udp_port_to_display, follow_tvb_tap_listener);
register_init_routine(udp_init);
}
void
proto_reg_handoff_udp(void)
{
capture_dissector_handle_t udp_cap_handle;
dissector_add_uint("ip.proto", IP_PROTO_UDP, udp_handle);
dissector_add_uint("ip.proto", IP_PROTO_UDPLITE, udplite_handle);
udp_cap_handle = create_capture_dissector_handle(capture_udp, hfi_udp->id);
capture_dissector_add_uint("ip.proto", IP_PROTO_UDP, udp_cap_handle);
udp_cap_handle = create_capture_dissector_handle(capture_udp, hfi_udplite->id);
capture_dissector_add_uint("ip.proto", IP_PROTO_UDPLITE, udp_cap_handle);
udp_tap = register_tap("udp");
udp_follow_tap = register_tap("udp_follow");
exported_pdu_tap = find_tap_id(EXPORT_PDU_TAP_NAME_LAYER_4);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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