wireshark/epan/dissectors/packet-coap.c

1724 lines
57 KiB
C

/* packet-coap.c
* Routines for CoAP packet disassembly
* draft-ietf-core-coap-14.txt
* draft-ietf-core-block-10.txt
* draft-ietf-core-observe-16.txt
* draft-ietf-core-link-format-06.txt
* Shoichi Sakane <sakane@tanu.org>
*
* Changes for draft-ietf-core-coap-17.txt
* Hauke Mehrtens <hauke@hauke-m.de>
*
* Support for CoAP over TCP, TLS and WebSockets
* https://tools.ietf.org/html/rfc8323
* Peter Wu <peter@lekensteyn.nl>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/conversation.h>
#include <epan/packet.h>
#include <epan/reassemble.h>
#include <epan/proto_data.h>
#include <epan/expert.h>
#include <epan/wmem_scopes.h>
#include <epan/to_str.h>
#include <epan/strutil.h>
#include "packet-dtls.h"
#include "packet-coap.h"
#include "packet-http.h"
#include "packet-tcp.h"
#include "packet-tls.h"
void proto_register_coap(void);
static dissector_table_t media_type_dissector_table;
static int proto_coap = -1;
static int hf_coap_length = -1;
static int hf_coap_version = -1;
static int hf_coap_ttype = -1;
static int hf_coap_token_len = -1;
static int hf_coap_token = -1;
static int hf_coap_mid = -1;
static int hf_coap_response_in = -1;
static int hf_coap_response_to = -1;
static int hf_coap_response_time = -1;
static int hf_coap_request_resend_in = -1;
static int hf_coap_response_resend_in = -1;
static int hf_coap_oscore_kid = -1;
static int hf_coap_oscore_kid_context = -1;
static int hf_coap_oscore_piv = -1;
static int hf_block_payload = -1;
static int hf_block_length = -1;
static int hf_blocks = -1;
static int hf_block = -1;
static int hf_block_overlap = -1;
static int hf_block_overlap_conflicts = -1;
static int hf_block_multiple_tails = -1;
static int hf_block_too_long = -1;
static int hf_block_error = -1;
static int hf_block_count = -1;
static int hf_block_reassembled_in = -1;
static int hf_block_reassembled_length = -1;
static gint ett_coap = -1;
static gint ett_block = -1;
static gint ett_blocks = -1;
static expert_field ei_retransmitted = EI_INIT;
static COAP_COMMON_LIST_T(dissect_coap_hf);
static dissector_handle_t coap_handle;
static dissector_handle_t oscore_handle;
/* CoAP's IANA-assigned TCP/UDP port numbers */
#define DEFAULT_COAP_PORT 5683
#define DEFAULT_COAPS_PORT 5684
/* indicators whether those are to be showed or not */
#define DEFAULT_COAP_CTYPE_VALUE ~0U
#define DEFAULT_COAP_BLOCK_NUMBER ~0U
/*
* Transaction Type
*/
#define TT_CON 0 // Confirmable
#define TT_NON 1 // Non-Confirmable
static const value_string vals_ttype[] = {
{ 0, "Confirmable" },
{ 1, "Non-Confirmable" },
{ 2, "Acknowledgement" },
{ 3, "Reset" },
{ 0, NULL },
};
static const value_string vals_ttype_short[] = {
{ 0, "CON" },
{ 1, "NON" },
{ 2, "ACK" },
{ 3, "RST" },
{ 0, NULL },
};
/*
* Method Code
* Response Code
* "c.dd" denotes (c << 5) | dd
*/
static const value_string vals_code[] = {
{ 0, "Empty Message" },
/* Method Codes */
{ 1, "GET" },
{ 2, "POST" },
{ 3, "PUT" },
{ 4, "DELETE" },
{ 5, "FETCH" }, /* RFC 8132 */
{ 6, "PATCH" }, /* RFC 8132 */
{ 7, "iPATCH" }, /* RFC 8132 */
/* Response Codes */
{ 65, "2.01 Created" },
{ 66, "2.02 Deleted" },
{ 67, "2.03 Valid" },
{ 68, "2.04 Changed" },
{ 69, "2.05 Content" },
{ 95, "2.31 Continue" },
{ 128, "4.00 Bad Request" },
{ 129, "4.01 Unauthorized" },
{ 130, "4.02 Bad Option" },
{ 131, "4.03 Forbidden" },
{ 132, "4.04 Not Found" },
{ 133, "4.05 Method Not Allowed" },
{ 134, "4.06 Not Acceptable" },
{ 136, "4.08 Request Entity Incomplete" }, /* RFC 7959 */
{ 137, "4.09 Conflict" }, /* RFC 8132 */
{ 140, "4.12 Precondition Failed" },
{ 141, "4.13 Request Entity Too Large" },
{ 143, "4.15 Unsupported Content-Format" },
{ 150, "4.22 Unprocessable Entity" }, /* RFC 8132 */
{ 157, "4.29 Too Many Requests" }, /* RFC 8516 */
{ 160, "5.00 Internal Server Error" },
{ 161, "5.01 Not Implemented" },
{ 162, "5.02 Bad Gateway" },
{ 163, "5.03 Service Unavailable" },
{ 164, "5.04 Gateway Timeout" },
{ 165, "5.05 Proxying Not Supported" },
{ 168, "5.08 Hop Limit Reached" }, /* RFC 8768 */
/* Signalling Codes */
{ 225, "7.01 CSM" }, /* RFC 8323 */
{ 226, "7.02 Ping" }, /* RFC 8323 */
{ 227, "7.03 Pong" }, /* RFC 8323 */
{ 228, "7.04 Release" }, /* RFC 8323 */
{ 229, "7.05 Abort" }, /* RFC 8323 */
{ 0, NULL },
};
value_string_ext coap_vals_code_ext = VALUE_STRING_EXT_INIT(vals_code);
const value_string coap_vals_observe_options[] = {
{ 0, "Register" },
{ 1, "Deregister" },
{ 0, NULL },
};
/*
* Option Headers
* No-Option must not be included in this structure, is handled in the function
* of the dissector, especially.
*/
#define COAP_OPT_IF_MATCH 1
#define COAP_OPT_URI_HOST 3
#define COAP_OPT_ETAG 4
#define COAP_OPT_IF_NONE_MATCH 5
#define COAP_OPT_OBSERVE 6 /* core-observe-16 */
#define COAP_OPT_URI_PORT 7
#define COAP_OPT_LOCATION_PATH 8
#define COAP_OPT_OBJECT_SECURITY 9 /* RFC 8613 */
#define COAP_OPT_URI_PATH 11
#define COAP_OPT_CONTENT_TYPE 12
#define COAP_OPT_MAX_AGE 14
#define COAP_OPT_URI_QUERY 15
#define COAP_OPT_HOP_LIMIT 16 /* RFC 8768 */
#define COAP_OPT_ACCEPT 17
#define COAP_OPT_LOCATION_QUERY 20
#define COAP_OPT_BLOCK2 23 /* RFC 7959 / RFC 8323 */
#define COAP_OPT_BLOCK1 27 /* RFC 7959 / RFC 8323 */
#define COAP_OPT_SIZE2 28 /* RFC 7959 */
#define COAP_OPT_PROXY_URI 35
#define COAP_OPT_PROXY_SCHEME 39
#define COAP_OPT_SIZE1 60
static const value_string vals_opt_type[] = {
{ COAP_OPT_IF_MATCH, "If-Match" },
{ COAP_OPT_URI_HOST, "Uri-Host" },
{ COAP_OPT_ETAG, "Etag" },
{ COAP_OPT_IF_NONE_MATCH, "If-None-Match" },
{ COAP_OPT_URI_PORT, "Uri-Port" },
{ COAP_OPT_LOCATION_PATH, "Location-Path" },
{ COAP_OPT_OBJECT_SECURITY,"OSCORE" },
{ COAP_OPT_URI_PATH, "Uri-Path" },
{ COAP_OPT_CONTENT_TYPE, "Content-Format" },
{ COAP_OPT_MAX_AGE, "Max-age" },
{ COAP_OPT_URI_QUERY, "Uri-Query" },
{ COAP_OPT_HOP_LIMIT, "Hop-Limit" },
{ COAP_OPT_ACCEPT, "Accept" },
{ COAP_OPT_LOCATION_QUERY, "Location-Query" },
{ COAP_OPT_PROXY_URI, "Proxy-Uri" },
{ COAP_OPT_PROXY_SCHEME, "Proxy-Scheme" },
{ COAP_OPT_SIZE1, "Size1" },
{ COAP_OPT_OBSERVE, "Observe" },
{ COAP_OPT_BLOCK2, "Block2" },
{ COAP_OPT_BLOCK1, "Block1" },
{ COAP_OPT_SIZE2, "Size2" },
{ 0, NULL },
};
struct coap_option_range_t {
guint type;
gint min;
gint max;
} coi[] = {
{ COAP_OPT_IF_MATCH, 0, 8 },
{ COAP_OPT_URI_HOST, 1, 255 },
{ COAP_OPT_ETAG, 1, 8 },
{ COAP_OPT_IF_NONE_MATCH, 0, 0 },
{ COAP_OPT_URI_PORT, 0, 2 },
{ COAP_OPT_LOCATION_PATH, 0, 255 },
{ COAP_OPT_OBJECT_SECURITY, 0, 255 },
{ COAP_OPT_URI_PATH, 0, 255 },
{ COAP_OPT_CONTENT_TYPE, 0, 2 },
{ COAP_OPT_MAX_AGE, 0, 4 },
{ COAP_OPT_URI_QUERY, 1, 255 },
{ COAP_OPT_HOP_LIMIT, 1, 1 },
{ COAP_OPT_ACCEPT, 0, 2 },
{ COAP_OPT_LOCATION_QUERY, 0, 255 },
{ COAP_OPT_PROXY_URI, 1,1034 },
{ COAP_OPT_PROXY_SCHEME, 1, 255 },
{ COAP_OPT_SIZE1, 0, 4 },
{ COAP_OPT_OBSERVE, 0, 3 },
{ COAP_OPT_BLOCK2, 0, 3 },
{ COAP_OPT_BLOCK1, 0, 3 },
{ COAP_OPT_SIZE2, 0, 4 },
};
static const value_string vals_ctype[] = {
{ 0, "text/plain; charset=utf-8" },
{ 40, "application/link-format" },
{ 41, "application/xml" },
{ 42, "application/octet-stream" },
{ 47, "application/exi" },
{ 50, "application/json" },
{ 51, "application/json-patch+json" },
{ 52, "application/merge-patch+json" },
{ 60, "application/cbor" },
{ 61, "application/cwt" },
{ 62, "application/multipart-core" },
{ 96, "application/cose; cose-type=\"cose-encrypt\"" },
{ 97, "application/cose; cose-type=\"cose-mac\"" },
{ 98, "application/cose; cose-type=\"cose-sign\"" },
{ 101, "application/cose-key" },
{ 102, "application/cose-key-set" },
{ 110, "application/senml+json" },
{ 111, "application/sensml+json" },
{ 112, "application/senml+cbor" },
{ 113, "application/sensml+cbor" },
{ 114, "application/senml-exi" },
{ 115, "application/sensml-exi" },
{ 256, "application/coap-group+json" },
{ 271, "application/dots+cbor" },
{ 272, "application/missing-blocks+cbor-seq" },
{ 280, "application/pkcs7-mime; smime-type=server-generated-key" },
{ 281, "application/pkcs7-mime; smime-type=certs-only" },
{ 284, "application/pkcs8" },
{ 285, "application/csrattrs" },
{ 286, "application/pkcs10" },
{ 287, "application/pkix-cert" },
{ 310, "application/senml+xml" },
{ 311, "application/sensml+xml" },
{ 320, "application/senml-etch+json" },
{ 322, "application/senml-etch+cbor" },
{ 432, "application/td+json" },
{ 1542, "application/vnd.oma.lwm2m+tlv" },
{ 1543, "application/vnd.oma.lwm2m+json" },
{ 10000, "application/vnd.ocf+cbor" },
{ 10001, "application/oscore" },
{ 11542, "application/vnd.oma.lwm2m+tlv" },
{ 11543, "application/vnd.oma.lwm2m+json" },
{ 0, NULL },
};
static const char *nullstr = "(null)";
static reassembly_table coap_block_reassembly_table;
static const fragment_items coap_block_frag_items = {
/* Fragment subtrees */
&ett_block,
&ett_blocks,
/* Fragment fields */
&hf_blocks,
&hf_block,
&hf_block_overlap,
&hf_block_overlap_conflicts,
&hf_block_multiple_tails,
&hf_block_too_long,
&hf_block_error,
&hf_block_count,
/* Reassembled in field */
&hf_block_reassembled_in,
/* Reassembled length field */
&hf_block_reassembled_length,
/* Reassembled data field */
NULL,
/* Tag */
"Block fragments"
};
void proto_reg_handoff_coap(void);
static conversation_t *
find_or_create_conversation_noaddrb(packet_info *pinfo, gboolean request)
{
conversation_t *conv=NULL;
address *addr_a;
address *addr_b;
guint32 port_a;
guint32 port_b;
if (pinfo->ptype != PT_TCP) {
if (request) {
addr_a = &pinfo->src;
addr_b = &pinfo->dst;
port_a = pinfo->srcport;
port_b = pinfo->destport;
} else {
addr_a = &pinfo->dst;
addr_b = &pinfo->src;
port_a = pinfo->destport;
port_b = pinfo->srcport;
}
/* Have we seen this conversation before? */
if((conv = find_conversation(pinfo->num, addr_a, addr_b,
conversation_pt_to_conversation_type(pinfo->ptype), port_a,
port_b, NO_ADDR_B|NO_PORT_B)) != NULL) {
if (pinfo->num > conv->last_frame) {
conv->last_frame = pinfo->num;
}
} else {
/* No, this is a new conversation. */
conv = conversation_new(pinfo->num, &pinfo->src,
&pinfo->dst, conversation_pt_to_conversation_type(pinfo->ptype),
pinfo->srcport, pinfo->destport, NO_ADDR2|NO_PORT2);
}
} else {
/* fetch the conversation created by the TCP dissector */
conv = find_conversation_pinfo(pinfo, 0);
DISSECTOR_ASSERT(conv);
}
return conv;
}
static gint
coap_get_opt_uint(tvbuff_t *tvb, gint offset, gint length)
{
switch (length) {
case 0:
return 0;
case 1:
return (guint)tvb_get_guint8(tvb, offset);
case 2:
return (guint)tvb_get_ntohs(tvb, offset);
case 3:
return (guint)tvb_get_ntoh24(tvb, offset);
case 4:
return (guint)tvb_get_ntohl(tvb, offset);
default:
return -1;
}
}
static gint
coap_opt_check(packet_info *pinfo, proto_tree *subtree, guint opt_num, gint opt_length, coap_common_dissect_t *dissect_hf)
{
int i;
for (i = 0; i < (int)(array_length(coi)); i++) {
if (coi[i].type == opt_num)
break;
}
if (i == (int)(array_length(coi))) {
if (opt_num >= 2048 && opt_num <= 65535) {
/* private, vendor-specific or reserved for experiments */
expert_add_info_format(pinfo, subtree, &dissect_hf->ei.opt_unknown_number,
"Unknown Option Number %u", opt_num);
} else {
expert_add_info_format(pinfo, subtree, &dissect_hf->ei.opt_invalid_number,
"Invalid Option Number %u", opt_num);
}
return -1;
}
if (opt_length < coi[i].min || opt_length > coi[i].max) {
expert_add_info_format(pinfo, subtree, &dissect_hf->ei.opt_invalid_range,
"Invalid Option Range: %d (%d < x < %d)", opt_length, coi[i].min, coi[i].max);
}
return 0;
}
static void
dissect_coap_opt_hex_string(tvbuff_t *tvb, packet_info *pinfo, proto_item *item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str;
if (opt_length == 0)
str = nullstr;
else
str = tvb_bytes_to_str_punct(pinfo->pool, tvb, offset, opt_length, ' ');
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_NA);
/* add info to the head of the packet detail */
proto_item_append_text(item, ": %s", str);
}
static void
dissect_coap_opt_uint(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
guint i = 0;
if (opt_length != 0) {
i = coap_get_opt_uint(tvb, offset, opt_length);
}
proto_tree_add_uint(subtree, hf, tvb, offset, opt_length, i);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %u", i);
}
static void
dissect_coap_opt_uri_host(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, coap_info *coinfo, int hf)
{
const guint8 *str;
proto_tree_add_item_ret_string(subtree, hf, tvb, offset, opt_length, ENC_ASCII, pinfo->pool, &str);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
/* forming a uri-string
* If the 'uri host' looks an IPv6 address, assuming that the address has
* to be enclosed by brackets.
*/
if (strchr(str, ':') == NULL) {
wmem_strbuf_append_printf(coinfo->uri_str_strbuf, "coap://%s", str);
} else {
wmem_strbuf_append_printf(coinfo->uri_str_strbuf, "coap://[%s]", str);
}
}
static void
dissect_coap_opt_uri_path(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, coap_info *coinfo, int hf)
{
const guint8 *str = NULL;
wmem_strbuf_append_c(coinfo->uri_str_strbuf, '/');
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
wmem_strbuf_append(coinfo->uri_str_strbuf, str);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
static void
dissect_coap_opt_uri_query(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, coap_info *coinfo, int hf)
{
const guint8 *str = NULL;
wmem_strbuf_append_c(coinfo->uri_query_strbuf,
(wmem_strbuf_get_len(coinfo->uri_query_strbuf) == 0) ? '?' : '&');
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
wmem_strbuf_append(coinfo->uri_query_strbuf, str);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
static void
dissect_coap_opt_location_path(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str = NULL;
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
static void
dissect_coap_opt_location_query(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str = NULL;
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
/* rfc8613 */
static void
dissect_coap_opt_object_security(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, packet_info *pinfo, coap_info *coinfo, coap_common_dissect_t *dissect_hf, guint8 code_class)
{
guint8 flag_byte = 0;
gboolean reserved = FALSE;
gboolean kid_context_present = FALSE;
gboolean kid_present = FALSE;
guint8 piv_len = 0;
guint8 kid_context_len = 0;
guint8 kid_len = 0;
coinfo->object_security = TRUE;
coinfo->oscore_info->piv = NULL;
coinfo->oscore_info->piv_len = 0;
coinfo->oscore_info->request_piv = NULL;
coinfo->oscore_info->request_piv_len = 0;
coinfo->oscore_info->kid_context = NULL;
coinfo->oscore_info->kid_context_len = 0;
coinfo->oscore_info->kid = NULL;
coinfo->oscore_info->kid_len = 0;
coinfo->oscore_info->response = FALSE;
if (opt_length == 0) { /* option length is zero, means flag byte is 0x00*/
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": 00 (no Flag Byte)");
} else {
flag_byte = tvb_get_guint8(tvb, offset);
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_reserved, tvb, offset, 1, ENC_BIG_ENDIAN);
reserved = flag_byte & COAP_OBJECT_SECURITY_RESERVED_MASK;
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_kid_context_present, tvb, offset, 1, ENC_BIG_ENDIAN);
kid_context_present = flag_byte & COAP_OBJECT_SECURITY_KID_CONTEXT_MASK;
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_kid_present, tvb, offset, 1, ENC_BIG_ENDIAN);
kid_present = flag_byte & COAP_OBJECT_SECURITY_KID_MASK;
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_piv_len, tvb, offset, 1, ENC_BIG_ENDIAN);
piv_len = (flag_byte & COAP_OBJECT_SECURITY_PIVLEN_MASK) >> 0;
/* kid_len is what remains in the option after all other fields are parsed
we calculate kid_len by subtracting from option length as we parse individual fields */
kid_len = opt_length;
offset += 1;
kid_len -= 1;
if (reserved) {
/* how these bits are handled is not yet specified */
expert_add_info_format(pinfo, subtree, &dissect_hf->ei.opt_object_security_bad, "Unsupported format");
}
if (piv_len > 0) {
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_piv, tvb, offset, piv_len, ENC_NA);
coinfo->oscore_info->piv = (guint8 *) tvb_memdup(pinfo->pool, tvb, offset, piv_len);
coinfo->oscore_info->piv_len = piv_len;
if (code_class == 0) {
/* If this is a request, copy PIV to request_piv */
coinfo->oscore_info->request_piv = (guint8 *) tvb_memdup(pinfo->pool, tvb, offset, piv_len);
coinfo->oscore_info->request_piv_len = piv_len;
}
offset += piv_len;
kid_len -= piv_len;
}
if (kid_context_present) {
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_kid_context_len, tvb, offset, 1, ENC_BIG_ENDIAN);
kid_context_len = tvb_get_guint8(tvb, offset);
offset += 1;
kid_len -= 1;
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_kid_context, tvb, offset, kid_context_len, ENC_NA);
coinfo->oscore_info->kid_context = (guint8 *) tvb_memdup(pinfo->pool, tvb, offset, kid_context_len);
coinfo->oscore_info->kid_context_len = kid_context_len;
offset += kid_context_len;
kid_len -= kid_context_len;
}
if (kid_present) {
proto_tree_add_item(subtree, dissect_hf->hf.opt_object_security_kid, tvb, offset, kid_len, ENC_NA);
coinfo->oscore_info->kid = (guint8 *) tvb_memdup(pinfo->pool, tvb, offset, kid_len);
coinfo->oscore_info->kid_len = kid_len;
}
proto_item_append_text(head_item, ": Key ID:%s, Key ID Context:%s, Partial IV:%s",
coinfo->oscore_info->kid == NULL ? nullstr : bytes_to_str(pinfo->pool, coinfo->oscore_info->kid, coinfo->oscore_info->kid_len),
coinfo->oscore_info->kid_context == NULL ? nullstr : bytes_to_str(pinfo->pool, coinfo->oscore_info->kid_context, coinfo->oscore_info->kid_context_len),
coinfo->oscore_info->piv == NULL ? nullstr : bytes_to_str(pinfo->pool, coinfo->oscore_info->piv, coinfo->oscore_info->piv_len));
}
}
static void
dissect_coap_opt_proxy_uri(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str = NULL;
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
static void
dissect_coap_opt_proxy_scheme(tvbuff_t *tvb, packet_info *pinfo, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str = NULL;
if (opt_length == 0) {
str = nullstr;
} else {
str = tvb_get_string_enc(pinfo->pool, tvb, offset, opt_length, ENC_ASCII);
}
proto_tree_add_item(subtree, hf, tvb, offset, opt_length, ENC_ASCII);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", format_text_string(pinfo->pool, str));
}
static void
dissect_coap_opt_ctype(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf, coap_info *coinfo)
{
if (opt_length == 0) {
coinfo->ctype_value = 0;
} else {
coinfo->ctype_value = coap_get_opt_uint(tvb, offset, opt_length);
}
coinfo->ctype_str = val_to_str(coinfo->ctype_value, vals_ctype, "Unknown Type %u");
proto_tree_add_string(subtree, hf, tvb, offset, opt_length, coinfo->ctype_str);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", coinfo->ctype_str);
}
static void
dissect_coap_opt_accept(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, int hf)
{
const guint8 *str = NULL;
if (opt_length == 0) {
str = nullstr;
} else {
guint value = coap_get_opt_uint(tvb, offset, opt_length);
str = val_to_str(value, vals_ctype, "Unknown Type %u");
}
proto_tree_add_string(subtree, hf, tvb, offset, opt_length, str);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": %s", str);
}
static void
dissect_coap_opt_block(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, coap_info *coinfo, coap_common_dissect_t *dissect_hf)
{
guint8 val = 0;
guint encoded_block_size;
guint block_esize;
if (opt_length == 0) {
coinfo->block_number = 0;
val = 0;
} else {
coinfo->block_number = coap_get_opt_uint(tvb, offset, opt_length) >> 4;
val = tvb_get_guint8(tvb, offset + opt_length - 1) & 0x0f;
}
proto_tree_add_uint(subtree, dissect_hf->hf.opt_block_number,
tvb, offset, opt_length, coinfo->block_number);
/* More flag in the end of the option */
coinfo->block_mflag = (val & COAP_BLOCK_MFLAG_MASK) >> 3;
proto_tree_add_uint(subtree, dissect_hf->hf.opt_block_mflag,
tvb, offset + opt_length - 1, 1, val);
/* block size */
encoded_block_size = val & COAP_BLOCK_SIZE_MASK;
block_esize = 1 << (encoded_block_size + 4);
proto_tree_add_uint_format(subtree, dissect_hf->hf.opt_block_size,
tvb, offset + opt_length - 1, 1, encoded_block_size, "Block Size: %u (%u encoded)", block_esize, encoded_block_size);
/* add info to the head of the packet detail */
proto_item_append_text(head_item, ": NUM:%u, M:%u, SZX:%u",
coinfo->block_number, coinfo->block_mflag, block_esize);
}
static void
dissect_coap_opt_uri_port(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree, gint offset, gint opt_length, coap_info *coinfo, int hf)
{
guint port = 0;
if (opt_length != 0) {
port = coap_get_opt_uint(tvb, offset, opt_length);
}
proto_tree_add_uint(subtree, hf, tvb, offset, opt_length, port);
proto_item_append_text(head_item, ": %u", port);
/* forming a uri-string */
wmem_strbuf_append_printf(coinfo->uri_str_strbuf, ":%u", port);
}
/*
* dissector for each option of CoAP.
* return the total length of the option including the header (e.g. delta and length).
*/
static int
dissect_coap_options_main(tvbuff_t *tvb, packet_info *pinfo, proto_tree *coap_tree, gint offset, guint8 opt_count, guint *opt_num, gint offset_end, guint8 code_class, coap_info *coinfo, coap_common_dissect_t *dissect_hf)
{
guint8 opt_jump;
gint opt_length, opt_length_ext, opt_delta, opt_delta_ext;
gint opt_length_ext_off = 0;
gint8 opt_length_ext_len = 0;
gint opt_delta_ext_off = 0;
gint8 opt_delta_ext_len = 0;
gint orig_offset = offset;
proto_tree *subtree;
proto_item *item;
char strbuf[56];
opt_jump = tvb_get_guint8(tvb, offset);
if (0xff == opt_jump)
return offset;
offset += 1;
/*
* section 3.1 in coap-17:
* Option Delta: 4-bit unsigned integer. A value between 0 and 12
* indicates the Option Delta. Three values are reserved for special
* constructs:
*
* 13: An 8-bit unsigned integer follows the initial byte and
* indicates the Option Delta minus 13.
*
* 14: A 16-bit unsigned integer in network byte order follows the
* initial byte and indicates the Option Delta minus 269.
*
* 15: Reserved for the Payload Marker. If the field is set to this
* value but the entire byte is not the payload marker, this MUST
* be processed as a message format error.
*/
switch (opt_jump & 0xf0) {
case 0xd0:
opt_delta_ext = tvb_get_guint8(tvb, offset);
opt_delta_ext_off = offset;
opt_delta_ext_len = 1;
offset += 1;
opt_delta = 13;
opt_delta += opt_delta_ext;
break;
case 0xe0:
opt_delta_ext = coap_get_opt_uint(tvb, offset, 2);
opt_delta_ext_off = offset;
opt_delta_ext_len = 2;
offset += 2;
opt_delta = 269;
opt_delta += opt_delta_ext;
break;
case 0xf0:
expert_add_info_format(pinfo, coap_tree, &dissect_hf->ei.opt_length_bad,
"end-of-options marker found, but option length isn't 15");
return -1;
default:
opt_delta = ((opt_jump & 0xf0) >> 4);
break;
}
*opt_num += opt_delta;
/*
* section 3.1 in coap-17:
* Option Length: 4-bit unsigned integer. A value between 0 and 12
* indicates the length of the Option Value, in bytes. Three values
* are reserved for special constructs:
*
* 13: An 8-bit unsigned integer precedes the Option Value and
* indicates the Option Length minus 13.
*
* 14: A 16-bit unsigned integer in network byte order precedes the
* Option Value and indicates the Option Length minus 269.
*
* 15: Reserved for future use. If the field is set to this value,
* it MUST be processed as a message format error.
*/
switch (opt_jump & 0x0f) {
case 0x0d:
opt_length_ext = tvb_get_guint8(tvb, offset);
opt_length_ext_off = offset;
opt_length_ext_len = 1;
offset += 1;
opt_length = 13;
opt_length += opt_length_ext;
break;
case 0x0e:
opt_length_ext = coap_get_opt_uint(tvb, offset, 2);
opt_length_ext_off = offset;
opt_length_ext_len = 2;
offset += 2;
opt_length = 269;
opt_length += opt_length_ext;
break;
case 0x0f:
expert_add_info_format(pinfo, coap_tree, &dissect_hf->ei.opt_length_bad,
"end-of-options marker found, but option delta isn't 15");
return -1;
default:
opt_length = (opt_jump & 0x0f);
break;
}
if (opt_length > offset_end - offset) {
expert_add_info_format(pinfo, coap_tree, &dissect_hf->ei.opt_length_bad,
"option longer than the package");
return -1;
}
snprintf(strbuf, sizeof(strbuf),
"#%u: %s", opt_count, val_to_str(*opt_num, vals_opt_type,
*opt_num % 14 == 0 ? "No-Op" : "Unknown Option (%d)"));
item = proto_tree_add_string(coap_tree, dissect_hf->hf.opt_name,
tvb, orig_offset, offset - orig_offset + opt_length, strbuf);
subtree = proto_item_add_subtree(item, dissect_hf->ett.option);
coap_opt_check(pinfo, subtree, *opt_num, opt_length, dissect_hf);
snprintf(strbuf, sizeof(strbuf),
"Type %u, %s, %s%s", *opt_num,
(*opt_num & 1) ? "Critical" : "Elective",
(*opt_num & 2) ? "Unsafe" : "Safe",
((*opt_num & 0x1e) == 0x1c) ? ", NoCacheKey" : "");
proto_tree_add_string(subtree, dissect_hf->hf.opt_desc,
tvb, orig_offset, offset - orig_offset + opt_length, strbuf);
proto_tree_add_item(subtree, dissect_hf->hf.opt_delta, tvb, orig_offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(subtree, dissect_hf->hf.opt_length, tvb, orig_offset, 1, ENC_BIG_ENDIAN);
if (opt_delta_ext_off && opt_delta_ext_len)
proto_tree_add_item(subtree, dissect_hf->hf.opt_delta_ext, tvb, opt_delta_ext_off, opt_delta_ext_len, ENC_BIG_ENDIAN);
if (opt_length_ext_off && opt_length_ext_len)
proto_tree_add_item(subtree, dissect_hf->hf.opt_length_ext, tvb, opt_length_ext_off, opt_length_ext_len, ENC_BIG_ENDIAN);
/* offset points the next to its option header */
switch (*opt_num) {
case COAP_OPT_CONTENT_TYPE:
dissect_coap_opt_ctype(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_ctype, coinfo);
break;
case COAP_OPT_MAX_AGE:
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_max_age);
break;
case COAP_OPT_PROXY_URI:
dissect_coap_opt_proxy_uri(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_proxy_uri);
break;
case COAP_OPT_PROXY_SCHEME:
dissect_coap_opt_proxy_scheme(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_proxy_scheme);
break;
case COAP_OPT_SIZE1:
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_size1);
break;
case COAP_OPT_ETAG:
dissect_coap_opt_hex_string(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_etag);
break;
case COAP_OPT_URI_HOST:
dissect_coap_opt_uri_host(tvb, pinfo, item, subtree, offset,
opt_length, coinfo, dissect_hf->hf.opt_uri_host);
break;
case COAP_OPT_LOCATION_PATH:
dissect_coap_opt_location_path(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_location_path);
break;
case COAP_OPT_URI_PORT:
dissect_coap_opt_uri_port(tvb, item, subtree, offset,
opt_length, coinfo, dissect_hf->hf.opt_uri_port);
break;
case COAP_OPT_LOCATION_QUERY:
dissect_coap_opt_location_query(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_location_query);
break;
case COAP_OPT_OBJECT_SECURITY:
dissect_coap_opt_object_security(tvb, item, subtree, offset,
opt_length, pinfo, coinfo, dissect_hf, code_class);
break;
case COAP_OPT_URI_PATH:
dissect_coap_opt_uri_path(tvb, pinfo, item, subtree, offset,
opt_length, coinfo, dissect_hf->hf.opt_uri_path);
break;
case COAP_OPT_OBSERVE:
if (code_class == 0) {
/* Request */
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_observe_req);
} else {
/* Response */
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_observe_rsp);
}
break;
case COAP_OPT_HOP_LIMIT:
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_hop_limit);
break;
case COAP_OPT_ACCEPT:
dissect_coap_opt_accept(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_accept);
break;
case COAP_OPT_IF_MATCH:
dissect_coap_opt_hex_string(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_if_match);
break;
case COAP_OPT_URI_QUERY:
dissect_coap_opt_uri_query(tvb, pinfo, item, subtree, offset,
opt_length, coinfo, dissect_hf->hf.opt_uri_query);
break;
case COAP_OPT_BLOCK2:
coinfo->block_option = 2;
dissect_coap_opt_block(tvb, item, subtree, offset,
opt_length, coinfo, dissect_hf);
break;
case COAP_OPT_BLOCK1:
coinfo->block_option = 1;
dissect_coap_opt_block(tvb, item, subtree, offset,
opt_length, coinfo, dissect_hf);
break;
case COAP_OPT_IF_NONE_MATCH:
break;
case COAP_OPT_SIZE2:
dissect_coap_opt_uint(tvb, item, subtree, offset,
opt_length, dissect_hf->hf.opt_block_size);
break;
default:
dissect_coap_opt_hex_string(tvb, pinfo, item, subtree, offset,
opt_length, dissect_hf->hf.opt_unknown);
break;
}
return offset + opt_length;
}
/*
* options dissector.
* return offset pointing the next of options. (i.e. the top of the paylaod
* or the end of the data.
*/
int
dissect_coap_options(tvbuff_t *tvb, packet_info *pinfo, proto_tree *coap_tree, gint offset, gint offset_end, guint8 code_class, coap_info *coinfo, coap_common_dissect_t *dissect_hf)
{
guint opt_num = 0;
int i;
guint8 endmarker;
/* loop for dissecting options */
for (i = 1; offset < offset_end; i++) {
offset = dissect_coap_options_main(tvb, pinfo, coap_tree,
offset, i, &opt_num, offset_end, code_class, coinfo, dissect_hf);
if (offset == -1)
return -1;
if (offset >= offset_end)
break;
endmarker = tvb_get_guint8(tvb, offset);
if (endmarker == 0xff) {
proto_tree_add_item(coap_tree, dissect_hf->hf.opt_end_marker, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
break;
}
}
return offset;
}
/*
* CoAP code dissector.
* return code value and updates the offset
* */
guint8
dissect_coap_code(tvbuff_t *tvb, proto_tree *tree, gint *offset, coap_common_dissect_t *dissect_hf, guint8 *code_class)
{
guint8 code;
proto_tree_add_item(tree, dissect_hf->hf.code, tvb, *offset, 1, ENC_BIG_ENDIAN);
code = tvb_get_guint8(tvb, *offset);
*code_class = code >> 5;
*offset += 1;
return code;
}
void
dissect_coap_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *coap_tree, proto_tree *parent_tree, gint offset, gint offset_end, guint8 code_class, coap_info *coinfo, coap_common_dissect_t *dissect_hf, gboolean oscore)
{
proto_tree *payload_tree;
proto_item *payload_item, *length_item;
tvbuff_t *payload_tvb;
guint payload_length = offset_end - offset;
const char *coap_ctype_str_dis;
http_message_info_t message_info;
char str_payload[80];
/* coinfo->ctype_value == DEFAULT_COAP_CTYPE_VALUE: No Content-Format option present */
if (coinfo->ctype_value == DEFAULT_COAP_CTYPE_VALUE) {
/*
* 5.5.2. Diagnostic Payload
*
* If no Content-Format option is given, the payload of responses
* indicating a client or server error is a brief human-readable
* diagnostic message, explaining the error situation. This diagnostic
* message MUST be encoded using UTF-8 [RFC3629], more specifically
* using Net-Unicode form [RFC5198].
*/
if ((code_class >= 4) && (code_class <= 5)) {
coinfo->ctype_str = "text/plain; charset=utf-8";
coap_ctype_str_dis = "text/plain";
} else {
/* Assume no Content-Format is opaque octet stream */
coinfo->ctype_str = "application/octet-stream";
coap_ctype_str_dis = coinfo->ctype_str;
}
}
/* coinfo->ctype_value == 0: Content-Format option present with length 0 */
else if (coinfo->ctype_value == 0) {
/* coinfo->ctype_str is already set by option parsing routine */
coap_ctype_str_dis = "text/plain";
} else {
coap_ctype_str_dis = coinfo->ctype_str;
}
snprintf(str_payload, sizeof(str_payload),
"Payload Content-Format: %s%s, Length: %u",
coinfo->ctype_str, coinfo->ctype_value == DEFAULT_COAP_CTYPE_VALUE ?
" (no Content-Format)" : "", payload_length);
payload_item = proto_tree_add_string(coap_tree, dissect_hf->hf.payload,
tvb, offset, payload_length,
str_payload);
payload_tree = proto_item_add_subtree(payload_item, dissect_hf->ett.payload);
proto_tree_add_string(payload_tree, dissect_hf->hf.payload_desc, tvb, offset, 0, coinfo->ctype_str);
length_item = proto_tree_add_uint(payload_tree, dissect_hf->hf.payload_length, tvb, offset, 0, payload_length);
proto_item_set_generated(length_item);
payload_tvb = tvb_new_subset_length(tvb, offset, payload_length);
message_info.type = HTTP_OTHERS;
message_info.media_str = wmem_strbuf_get_str(coinfo->uri_str_strbuf);
dissector_try_string(media_type_dissector_table, coap_ctype_str_dis,
payload_tvb, pinfo, parent_tree, &message_info);
if (coinfo->object_security && !oscore) {
proto_item_set_text(payload_item, "Encrypted OSCORE Data");
call_dissector_with_data(oscore_handle, payload_tvb, pinfo, parent_tree, coinfo->oscore_info);
}
}
static guint32
coap_frame_length(tvbuff_t *tvb, guint offset, gint *size)
{
/*
* Decode Len and Extended Length according to
* https://tools.ietf.org/html/rfc8323#page-10
*/
guint8 len = tvb_get_guint8(tvb, offset) >> 4;
switch (len) {
default:
*size = 1;
return len;
case 13:
if (tvb_reported_length_remaining(tvb, offset) < 2) {
*size = -1;
return 0;
}
*size = 2;
return tvb_get_guint8(tvb, offset + 1) + 13;
case 14:
if (tvb_reported_length_remaining(tvb, offset) < 3) {
*size = -1;
return 0;
}
*size = 3;
return tvb_get_ntohs(tvb, offset + 1) + 269;
case 15:
if (tvb_reported_length_remaining(tvb, offset) < 5) {
*size = -1;
return 0;
}
*size = 5;
return tvb_get_ntohl(tvb, offset + 1) + 65805;
}
}
static int
dissect_coap_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, gboolean is_tcp, gboolean is_websocket)
{
gint offset = 0;
proto_item *coap_root;
proto_item *pi;
proto_tree *coap_tree;
gint length_size = 0;
guint8 ttype = G_MAXUINT8;
guint32 token_len;
guint8 code;
guint8 code_class;
guint32 mid = 0;
gint coap_length;
gchar *coap_token_str;
coap_info *coinfo;
conversation_t *conversation;
coap_conv_info *ccinfo;
coap_transaction *coap_trans = NULL;
coap_request_response *coap_req_rsp = NULL;
// TODO support TCP/WebSocket/TCP with more than one PDU per packet.
// These probably require a unique coinfo for each.
/* Allocate information for upper layers */
coinfo = (coap_info *)p_get_proto_data(wmem_file_scope(), pinfo, proto_coap, 0);
if (coinfo == NULL)
{
coinfo = wmem_new0(wmem_file_scope(), coap_info);
p_add_proto_data(wmem_file_scope(), pinfo, proto_coap, 0, coinfo);
}
/* initialize the CoAP length and the content-Format */
/*
* The length of CoAP message is not specified in the CoAP header using
* UDP or WebSockets. The lower layers provide it. For TCP/TLS, an
* explicit length is present.
*/
coap_length = tvb_reported_length(tvb);
if (is_tcp && !is_websocket) {
token_len = tvb_get_guint8(tvb, offset) & 0xf;
coap_length = coap_frame_length(tvb, offset, &length_size);
if (length_size < 0) {
pinfo->desegment_offset = offset;
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
return tvb_reported_length(tvb);
}
/*
* Length of the whole CoAP frame includes the (Extended) Length fields
* (1 to 4 bytes), the Code (1 byte) and token length (normally 0 to 8
* bytes), plus everything afterwards.
*/
coap_length += 1 + token_len + length_size;
if (coap_length > tvb_reported_length_remaining(tvb, offset)) {
pinfo->desegment_offset = offset;
pinfo->desegment_len = coap_length - tvb_reported_length_remaining(tvb, offset);
return tvb_reported_length(tvb);
}
}
coinfo->ctype_str = "";
coinfo->ctype_value = DEFAULT_COAP_CTYPE_VALUE;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CoAP");
col_clear(pinfo->cinfo, COL_INFO);
coap_root = proto_tree_add_item(parent_tree, proto_coap, tvb, offset, -1, ENC_NA);
coap_tree = proto_item_add_subtree(coap_root, ett_coap);
if (!is_tcp) {
proto_tree_add_item(coap_tree, hf_coap_version, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(coap_tree, hf_coap_ttype, tvb, offset, 1, ENC_BIG_ENDIAN);
ttype = (tvb_get_guint8(tvb, offset) & COAP_TYPE_MASK) >> 4;
proto_tree_add_item_ret_uint(coap_tree, hf_coap_token_len, tvb, offset, 1, ENC_BIG_ENDIAN, &token_len);
offset += 1;
code = dissect_coap_code(tvb, coap_tree, &offset, &dissect_coap_hf, &code_class);
proto_tree_add_item(coap_tree, hf_coap_mid, tvb, offset, 2, ENC_BIG_ENDIAN);
mid = tvb_get_ntohs(tvb, offset);
offset += 2;
col_add_fstr(pinfo->cinfo, COL_INFO,
"%s, MID:%u, %s",
val_to_str(ttype, vals_ttype_short, "Unknown %u"),
mid,
val_to_str_ext(code, &coap_vals_code_ext, "Unknown %u"));
/* append the header information */
proto_item_append_text(coap_root,
", %s, %s, MID:%u",
val_to_str(ttype, vals_ttype, "Unknown %u"),
val_to_str_ext(code, &coap_vals_code_ext, "Unknown %u"),
mid);
} else {
guint len = coap_length;
if (is_websocket) {
len = tvb_get_guint8(tvb, offset) >> 4;
length_size = 1;
}
proto_tree_add_uint(coap_tree, hf_coap_length, tvb, offset, length_size, len);
proto_tree_add_item_ret_uint(coap_tree, hf_coap_token_len, tvb, offset, 1, ENC_BIG_ENDIAN, &token_len);
offset += length_size;
code = dissect_coap_code(tvb, coap_tree, &offset, &dissect_coap_hf, &code_class);
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL,
val_to_str_ext(code, &coap_vals_code_ext, "Unknown %u"));
/* append the header information */
proto_item_append_text(coap_root,
", %s",
val_to_str_ext(code, &coap_vals_code_ext, "Unknown %u"));
}
/* initialize the external value */
coinfo->block_option = 0;
coinfo->block_number = DEFAULT_COAP_BLOCK_NUMBER;
coinfo->block_mflag = 0;
coinfo->uri_str_strbuf = wmem_strbuf_sized_new(pinfo->pool, 0, 1024);
coinfo->uri_query_strbuf = wmem_strbuf_sized_new(pinfo->pool, 0, 1024);
/* Allocate pointers and static elements of oscore_info_t, arrays are allocated only if object security option is found during option parsing */
coinfo->oscore_info = wmem_new0(pinfo->pool, oscore_info_t);
coinfo->object_security = FALSE;
coap_token_str = NULL;
if (token_len > 0)
{
/* This has to be file scope as the token string is stored in the map
* for conversation lookup */
coap_token_str = tvb_bytes_to_str_punct(wmem_file_scope(), tvb, offset, token_len, ' ');
proto_tree_add_item(coap_tree, hf_coap_token,
tvb, offset, token_len, ENC_NA);
offset += token_len;
}
/* process options */
offset = dissect_coap_options(tvb, pinfo, coap_tree, offset, coap_length, code_class, coinfo, &dissect_coap_hf);
if (offset == -1)
return tvb_captured_length(tvb);
/* Use conversations to track state for request/response */
conversation = find_or_create_conversation_noaddrb(pinfo, (code_class == 0));
/* Retrieve or create state structure for this conversation */
ccinfo = (coap_conv_info *)conversation_get_proto_data(conversation, proto_coap);
if (!ccinfo) {
/* No state structure - create it */
ccinfo = wmem_new(wmem_file_scope(), coap_conv_info);
ccinfo->messages = wmem_map_new(wmem_file_scope(), g_str_hash, g_str_equal);
conversation_add_proto_data(conversation, proto_coap, ccinfo);
}
/* Everything based on tokens */
if (coap_token_str != NULL) {
/* Process request/response in conversation */
if (code != 0) { /* Ignore empty messages */
/* Try and look up a matching token. If it's the first
* sight of a request, there shouldn't be one */
coap_trans = (coap_transaction *)wmem_map_lookup(ccinfo->messages, coap_token_str);
if (!coap_trans) {
if ((!PINFO_FD_VISITED(pinfo)) && (code_class == 0)) {
/* New request - log it */
coap_trans = wmem_new0(wmem_file_scope(), coap_transaction);
coap_trans->req_rsp = wmem_map_new(wmem_file_scope(), g_direct_hash, g_direct_equal);
if (coinfo->uri_str_strbuf) {
/* Store the URI into CoAP transaction info */
coap_trans->uri_str_strbuf = wmem_strbuf_new(wmem_file_scope(), wmem_strbuf_get_str(coinfo->uri_str_strbuf));
}
if (coinfo->oscore_info) {
coap_trans->oscore_info = (oscore_info_t *) wmem_memdup(wmem_file_scope(), coinfo->oscore_info, sizeof(oscore_info_t));
if (coinfo->oscore_info->kid) {
coap_trans->oscore_info->kid = (guint8 *) wmem_memdup(wmem_file_scope(), coinfo->oscore_info->kid, coinfo->oscore_info->kid_len);
}
if (coinfo->oscore_info->kid_context) {
coap_trans->oscore_info->kid_context = (guint8 *) wmem_memdup(wmem_file_scope(), coinfo->oscore_info->kid_context, coinfo->oscore_info->kid_context_len);
}
if (coinfo->oscore_info->piv) {
coap_trans->oscore_info->request_piv = (guint8 *) wmem_memdup(wmem_file_scope(), coinfo->oscore_info->request_piv, coinfo->oscore_info->request_piv_len);
}
}
wmem_map_insert(ccinfo->messages, coap_token_str, (void *)coap_trans);
}
} else {
if ((code_class >= 2) && (code_class <= 5)) {
if (coap_trans->uri_str_strbuf) {
/* Copy the URI stored in matching transaction info into CoAP packet info */
coinfo->uri_str_strbuf = wmem_strbuf_new(pinfo->pool, wmem_strbuf_get_str(coap_trans->uri_str_strbuf));
}
if (coap_trans->oscore_info) {
/* Copy OSCORE info in matching transaction info into CoAP packet info */
if (coap_trans->oscore_info->kid) {
coinfo->oscore_info->kid = (guint8 *) wmem_memdup(pinfo->pool, coap_trans->oscore_info->kid, coap_trans->oscore_info->kid_len);
}
coinfo->oscore_info->kid_len = coap_trans->oscore_info->kid_len;
if (coap_trans->oscore_info->kid_context) {
coinfo->oscore_info->kid_context = (guint8 *) wmem_memdup(pinfo->pool, coap_trans->oscore_info->kid_context, coap_trans->oscore_info->kid_context_len);
}
coinfo->oscore_info->kid_context_len = coap_trans->oscore_info->kid_context_len;
if (coap_trans->oscore_info->request_piv) {
coinfo->oscore_info->request_piv = (guint8 *) wmem_memdup(pinfo->pool, coap_trans->oscore_info->request_piv, coap_trans->oscore_info->request_piv_len);
}
coinfo->oscore_info->request_piv_len = coap_trans->oscore_info->request_piv_len;
coinfo->oscore_info->response = TRUE;
}
}
}
if (coap_trans) {
coap_req_rsp = (coap_request_response *)wmem_map_lookup(coap_trans->req_rsp, GINT_TO_POINTER(mid));
if (!PINFO_FD_VISITED(pinfo)) {
if (!coap_req_rsp) {
coap_req_rsp = wmem_new0(wmem_file_scope(), coap_request_response);
wmem_map_insert(coap_trans->req_rsp, GINT_TO_POINTER(mid), (void *)coap_req_rsp);
}
if (code_class == 0) {
/* This is a request */
if (coap_req_rsp->req_frame == 0) {
/* Log the first request frame */
coap_req_rsp->req_frame = pinfo->num;
coap_req_rsp->req_time = pinfo->abs_ts;
}
} else if ((code_class >= 2) && (code_class <= 5)) {
/* This is a reply */
if (coap_req_rsp->rsp_frame == 0) {
/* Log the first matching response frame */
coap_req_rsp->rsp_frame = pinfo->num;
}
}
}
}
}
}
/* dissect the payload */
if (coap_length > offset) {
if (coinfo->block_number == DEFAULT_COAP_BLOCK_NUMBER) {
dissect_coap_payload(tvb, pinfo, coap_tree, parent_tree, offset, coap_length,
code_class, coinfo, &dissect_coap_hf, FALSE);
} else {
proto_tree_add_bytes_format(coap_tree, hf_block_payload, tvb, offset,
coap_length - offset, NULL, "Block Payload");
pi = proto_tree_add_uint(coap_tree, hf_block_length, tvb, offset, 0, coap_length - offset);
proto_item_set_generated(pi);
fragment_head *frag_msg = fragment_add_seq_check(&coap_block_reassembly_table, tvb, offset,
pinfo, 0, NULL, coinfo->block_number,
coap_length - offset, coinfo->block_mflag);
tvbuff_t *frag_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CoAP blocks",
frag_msg, &coap_block_frag_items, NULL, coap_tree);
if (frag_tvb) {
dissect_coap_payload(frag_tvb, pinfo, coap_tree, parent_tree, 0, tvb_reported_length(frag_tvb),
code_class, coinfo, &dissect_coap_hf, FALSE);
}
}
}
/* add informations to the packet list */
if (coap_token_str != NULL)
col_append_fstr(pinfo->cinfo, COL_INFO, ", TKN:%s", coap_token_str);
if (coinfo->block_number != DEFAULT_COAP_BLOCK_NUMBER) {
/* The M bit is used in Block1 Option in a request and in Block2 Option in a response */
gboolean mflag_is_used = (((coinfo->block_option == 1) && (code_class == 0)) ||
((coinfo->block_option == 2) && (code_class >= 2) && (code_class <= 5)));
col_append_fstr(pinfo->cinfo, COL_INFO, ", %sBlock #%u",
(coinfo->block_mflag || !mflag_is_used) ? "" : "End of ", coinfo->block_number);
}
if (wmem_strbuf_get_len(coinfo->uri_str_strbuf) > 0) {
col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", format_text(pinfo->pool, wmem_strbuf_get_str(coinfo->uri_str_strbuf), wmem_strbuf_get_len(coinfo->uri_str_strbuf)));
/* Add a generated protocol item as well */
pi = proto_tree_add_string(coap_tree, dissect_coap_hf.hf.opt_uri_path_recon, tvb, 0, 0, wmem_strbuf_get_str(coinfo->uri_str_strbuf));
proto_item_set_generated(pi);
}
if (wmem_strbuf_get_len(coinfo->uri_query_strbuf) > 0)
col_append_str(pinfo->cinfo, COL_INFO, format_text(pinfo->pool, wmem_strbuf_get_str(coinfo->uri_query_strbuf), wmem_strbuf_get_len(coinfo->uri_query_strbuf)));
if (coap_req_rsp != NULL) {
/* Print state tracking in the tree */
if (code_class == 0) {
/* This is a request */
if (coap_req_rsp->rsp_frame) {
pi = proto_tree_add_uint(coap_tree, hf_coap_response_in,
tvb, 0, 0, coap_req_rsp->rsp_frame);
proto_item_set_generated(pi);
}
if ((ttype == TT_CON || ttype == TT_NON) && (coap_req_rsp->req_frame != pinfo->num)) {
col_append_str(pinfo->cinfo, COL_INFO, " [Retransmission]");
pi = proto_tree_add_uint(coap_tree, hf_coap_request_resend_in,
tvb, 0, 0, coap_req_rsp->req_frame);
proto_item_set_generated(pi);
expert_add_info(pinfo, pi, &ei_retransmitted);
}
} else if ((code_class >= 2) && (code_class <= 5)) {
/* This is a reply */
if (coap_req_rsp->req_frame) {
nstime_t ns;
pi = proto_tree_add_uint(coap_tree, hf_coap_response_to,
tvb, 0, 0, coap_req_rsp->req_frame);
proto_item_set_generated(pi);
nstime_delta(&ns, &pinfo->abs_ts, &coap_req_rsp->req_time);
pi = proto_tree_add_time(coap_tree, hf_coap_response_time, tvb, 0, 0, &ns);
proto_item_set_generated(pi);
}
if ((ttype == TT_CON || ttype == TT_NON) && (coap_req_rsp->rsp_frame != pinfo->num)) {
col_append_str(pinfo->cinfo, COL_INFO, " [Retransmission]");
pi = proto_tree_add_uint(coap_tree, hf_coap_response_resend_in,
tvb, 0, 0, coap_req_rsp->rsp_frame);
proto_item_set_generated(pi);
expert_add_info(pinfo, pi, &ei_retransmitted);
}
}
}
if (coap_trans != NULL) {
if ((code_class >= 2) && (code_class <= 5)) {
/* This is a reply */
if (coinfo->object_security && coap_trans->oscore_info) {
pi = proto_tree_add_bytes(coap_tree, hf_coap_oscore_kid, tvb, 0, coap_trans->oscore_info->kid_len, coap_trans->oscore_info->kid);
proto_item_set_generated(pi);
pi = proto_tree_add_bytes(coap_tree, hf_coap_oscore_kid_context, tvb, 0, coap_trans->oscore_info->kid_context_len, coap_trans->oscore_info->kid_context);
proto_item_set_generated(pi);
if (coinfo->oscore_info->piv_len) {
pi = proto_tree_add_bytes(coap_tree, hf_coap_oscore_piv, tvb, 0, coinfo->oscore_info->piv_len, coinfo->oscore_info->piv);
} else {
pi = proto_tree_add_bytes(coap_tree, hf_coap_oscore_piv, tvb, 0, coinfo->oscore_info->request_piv_len, coinfo->oscore_info->request_piv);
}
proto_item_set_generated(pi);
}
}
}
return coap_length;
}
static int
dissect_coap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
wmem_list_frame_t *prev_layer;
const char *name;
/* retrieve parent protocol */
prev_layer = wmem_list_frame_prev(wmem_list_tail(pinfo->layers));
if (prev_layer) {
name = proto_get_protocol_filter_name(GPOINTER_TO_INT(wmem_list_frame_data(prev_layer)));
} else {
name = NULL;
}
if (proto_is_frame_protocol(pinfo->layers, "websocket")) {
/* WebSockets */
return dissect_coap_message(tvb, pinfo, tree, TRUE, TRUE);
} else if (!g_strcmp0(name, "tcp") || !g_strcmp0(name, "tls")) {
/* TCP */
return dissect_coap_message(tvb, pinfo, tree, TRUE, FALSE);
} else {
/* Assume UDP */
return dissect_coap_message(tvb, pinfo, tree, FALSE, FALSE);
}
}
/*
* Protocol initialization
*/
void
proto_register_coap(void)
{
static hf_register_info hf[] = {
{ &hf_coap_length,
{ "Length", "coap.length",
FT_UINT32, BASE_DEC, NULL, 0,
"Length of the CoAP frame, combining Len and Extended Length (if any) fields", HFILL }
},
{ &hf_coap_version,
{ "Version", "coap.version",
FT_UINT8, BASE_DEC, NULL, COAP_VERSION_MASK,
NULL, HFILL }
},
{ &hf_coap_ttype,
{ "Type", "coap.type",
FT_UINT8, BASE_DEC, VALS(vals_ttype), COAP_TYPE_MASK,
NULL, HFILL }
},
{ &hf_coap_token_len,
{ "Token Length", "coap.token_len",
FT_UINT8, BASE_DEC, NULL, COAP_TOKEN_LEN_MASK,
NULL, HFILL }
},
{ &hf_coap_token,
{ "Token", "coap.token",
FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_coap_mid,
{ "Message ID", "coap.mid",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_coap_response_in,
{ "Response In", "coap.response_in",
FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_RESPONSE), 0x0,
"The response to this CoAP request is in this frame", HFILL }
},
{ &hf_coap_response_to,
{ "Request In", "coap.response_to",
FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_REQUEST), 0x0,
"This is a response to the CoAP request in this frame", HFILL }
},
{ &hf_coap_response_time,
{ "Response Time", "coap.response_time",
FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
"The time between the Call and the Reply", HFILL }
},
{ &hf_coap_request_resend_in,
{ "Retransmission of request in", "coap.request_first_in",
FT_FRAMENUM, BASE_NONE, NULL, 0x0,
"This request was first sent in this frame", HFILL }
},
{ &hf_coap_response_resend_in,
{ "Retransmission of response in", "coap.response_first_in",
FT_FRAMENUM, BASE_NONE, NULL, 0x0,
"This response was first sent in this frame", HFILL }
},
{ &hf_coap_oscore_kid,
{ "OSCORE Key ID", "coap.oscore_kid", FT_BYTES, BASE_NONE, NULL, 0x0,
"Matched OSCORE Key ID", HFILL }
},
{ &hf_coap_oscore_kid_context,
{ "OSCORE Key ID Context", "coap.oscore_kid_context", FT_BYTES, BASE_NONE, NULL, 0x0,
"Matched OSCORE Key ID Context", HFILL }
},
{ &hf_coap_oscore_piv,
{ "OSCORE Partial IV", "coap.oscore_piv", FT_BYTES, BASE_NONE, NULL, 0x0,
"Matched OSCORE Partial IV", HFILL }
},
{ &hf_block_payload,
{ "Block Payload", "coap.block_payload",
FT_BYTES, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block_length,
{ "Block Length", "coap.block_length",
FT_UINT32, BASE_DEC, NULL, 0x00,
NULL, HFILL }
},
{ &hf_blocks,
{ "Blocks", "coap.blocks",
FT_NONE, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block,
{ "Block", "coap.block",
FT_FRAMENUM, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block_overlap,
{ "Block overlap", "coap.block.overlap",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_block_overlap_conflicts,
{ "Block overlapping with conflicting data", "coap.block.overlap.conflicts",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_block_multiple_tails,
{ "Block has multiple tails", "coap.block.multiple_tails",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_block_too_long,
{ "Block too long", "coap.block.too_long",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_block_error,
{ "Block defragmentation error", "coap.block.error",
FT_FRAMENUM, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block_count,
{ "Block count", "coap.block.count",
FT_UINT32, BASE_DEC, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block_reassembled_in,
{ "Reassembled in", "coap.block.reassembled.in",
FT_FRAMENUM, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_block_reassembled_length,
{ "Reassembled block length", "coap.block.reassembled.length",
FT_UINT32, BASE_DEC, NULL, 0x00,
NULL, HFILL }
},
COAP_COMMON_HF_LIST(dissect_coap_hf, "coap")
};
static gint *ett[] = {
&ett_coap,
&ett_block,
&ett_blocks,
COAP_COMMON_ETT_LIST(dissect_coap_hf)
};
static ei_register_info ei[] = {
{ &ei_retransmitted,
{ "coap.retransmitted", PI_SEQUENCE, PI_NOTE,
"Retransmitted", EXPFILL }
},
COAP_COMMON_EI_LIST(dissect_coap_hf, "coap")
};
expert_module_t *expert_coap;
proto_coap = proto_register_protocol("Constrained Application Protocol", "CoAP", "coap");
proto_register_field_array(proto_coap, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_coap = expert_register_protocol(proto_coap);
expert_register_field_array(expert_coap, ei, array_length(ei));
reassembly_table_register (&coap_block_reassembly_table, &addresses_reassembly_table_functions);
coap_handle = register_dissector("coap", dissect_coap, proto_coap);
}
void
proto_reg_handoff_coap(void)
{
media_type_dissector_table = find_dissector_table("media_type");
dissector_add_uint_with_preference("udp.port", DEFAULT_COAP_PORT, coap_handle);
dtls_dissector_add(DEFAULT_COAPS_PORT, coap_handle);
/* TCP, TLS, WebSockets (RFC 8323) */
dissector_add_uint_with_preference("tcp.port", DEFAULT_COAP_PORT, coap_handle);
ssl_dissector_add(DEFAULT_COAPS_PORT, coap_handle);
dissector_add_string("tls.alpn", "coap", coap_handle);
dissector_add_string("ws.protocol", "coap", coap_handle);
oscore_handle = find_dissector("oscore");
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/