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6LoWPAN: Display UDP NHC port encoding field as 2-bit 

Reference: RFC 6282 Section 4.3.3

Change-Id: I8ff46452d80b1aba4545967bc05310c341f6e174
Reviewed-on: https://code.wireshark.org/review/19297
Reviewed-by: João Valverde <j@v6e.pt>
This commit is contained in:
João Valverde 2016-12-15 23:48:25 +00:00 committed by João Valverde
parent 1a57d81042
commit f923009c77
1 changed files with 42 additions and 31 deletions
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73
epan/dissectors/packet-6lowpan.c
View File

@ -171,8 +171,7 @@ void proto_reg_handoff_6lowpan(void);
/* NHC UDP fields. */
#define LOWPAN_NHC_UDP_CHECKSUM 0x04
#define LOWPAN_NHC_UDP_SRCPORT 0x02
#define LOWPAN_NHC_UDP_DSTPORT 0x01
#define LOWPAN_NHC_UDP_PORTS 0x03
/* 6LoWPAN Mesh Header */
#define LOWPAN_MESH_HEADER_V 0x20
@ -186,9 +185,15 @@ void proto_reg_handoff_6lowpan(void);
#define IP6OPT_PAD1 0x00
#define IP6OPT_PADN 0x01
/* UDP port compression encoding */
#define LOWPAN_NHC_UDP_PORT_INLINE 0x0
#define LOWPAN_NHC_UDP_PORT_8BIT_DST 0x1
#define LOWPAN_NHC_UDP_PORT_8BIT_SRC 0x2
#define LOWPAN_NHC_UDP_PORT_12BIT 0x3
/* Compressed port number offset. */
#define LOWPAN_PORT_8BIT_OFFSET 0xf000
#define LOWPAN_PORT_12BIT_OFFSET (LOWPAN_PORT_8BIT_OFFSET | 0xb0)
#define LOWPAN_PORT_12BIT_OFFSET 0xf0b0
/* 6LoWPAN interface identifier length. */
#define LOWPAN_IFC_ID_LEN 8
@ -239,8 +244,7 @@ static int hf_6lowpan_nhc_ext_reserved = -1;
/* NHC UDP compression header fields. */
static int hf_6lowpan_nhc_udp_checksum = -1;
static int hf_6lowpan_nhc_udp_src = -1;
static int hf_6lowpan_nhc_udp_dst = -1;
static int hf_6lowpan_nhc_udp_ports = -1;
/* Inline IPv6 header fields. */
static int hf_6lowpan_traffic_class = -1;
@ -385,6 +389,13 @@ static const value_string lowpan_nhc_eid [] = {
{ LOWPAN_NHC_EID_IPV6, "IPv6 header" },
{ 0, NULL }
};
static const value_string lowpan_udp_ports [] = {
{ LOWPAN_NHC_UDP_PORT_INLINE, "Inline" },
{ LOWPAN_NHC_UDP_PORT_8BIT_DST, "Source port inline, first 8 bits of destination port elided" },
{ LOWPAN_NHC_UDP_PORT_8BIT_SRC, "Destination port inline, first 8 bits of source port elided" },
{ LOWPAN_NHC_UDP_PORT_12BIT, "12 bits of both ports elided" },
{ 0, NULL }
};
/* Reassembly Data */
static int hf_6lowpan_fragments = -1;
static int hf_6lowpan_fragment = -1;
@ -2043,41 +2054,44 @@ dissect_6lowpan_iphc_nhc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gi
proto_tree_add_bits_item(nhc_tree, hf_6lowpan_nhc_pattern, tvb, offset<<3, LOWPAN_NHC_PATTERN_UDP_BITS, ENC_BIG_ENDIAN);
/* Get and display the UDP header compression options */
proto_tree_add_item(nhc_tree, hf_6lowpan_nhc_udp_checksum, tvb, offset, 1, ENC_NA);
proto_tree_add_item(nhc_tree, hf_6lowpan_nhc_udp_ports, tvb, offset, 1, ENC_NA);
udp_flags = tvb_get_guint8(tvb, offset);
proto_tree_add_boolean(nhc_tree, hf_6lowpan_nhc_udp_checksum, tvb, offset, 1, udp_flags & LOWPAN_NHC_UDP_CHECKSUM);
proto_tree_add_boolean(nhc_tree, hf_6lowpan_nhc_udp_src, tvb, offset, 1, udp_flags & LOWPAN_NHC_UDP_SRCPORT);
proto_tree_add_boolean(nhc_tree, hf_6lowpan_nhc_udp_dst, tvb, offset, 1, udp_flags & LOWPAN_NHC_UDP_DSTPORT);
offset += 1;
/* Get and display the ports. */
switch (udp_flags & (LOWPAN_NHC_UDP_SRCPORT | LOWPAN_NHC_UDP_DSTPORT)) {
case (LOWPAN_NHC_UDP_SRCPORT | LOWPAN_NHC_UDP_DSTPORT):
udp.src_port = LOWPAN_PORT_12BIT_OFFSET + (tvb_get_guint8(tvb, offset) >> 4);
udp.dst_port = LOWPAN_PORT_12BIT_OFFSET + (tvb_get_guint8(tvb, offset) & 0x0f);
src_bitlen = 4;
dst_bitlen = 4;
break;
case LOWPAN_NHC_UDP_SRCPORT:
udp.src_port = LOWPAN_PORT_8BIT_OFFSET + tvb_get_guint8(tvb, offset);
udp.dst_port = tvb_get_ntohs(tvb, offset + 1);
src_bitlen = 8;
switch (udp_flags & LOWPAN_NHC_UDP_PORTS) {
case LOWPAN_NHC_UDP_PORT_INLINE:
udp.src_port = tvb_get_ntohs(tvb, offset);
udp.dst_port = tvb_get_ntohs(tvb, offset+2);
src_bitlen = 16;
dst_bitlen = 16;
break;
case LOWPAN_NHC_UDP_DSTPORT:
case LOWPAN_NHC_UDP_PORT_8BIT_DST:
udp.src_port = tvb_get_ntohs(tvb, offset);
udp.dst_port = LOWPAN_PORT_8BIT_OFFSET + tvb_get_guint8(tvb, offset + 2);
src_bitlen = 16;
dst_bitlen = 8;
break;
default:
udp.src_port = tvb_get_ntohs(tvb, offset);
udp.dst_port = tvb_get_ntohs(tvb, offset+2);
src_bitlen = 16;
case LOWPAN_NHC_UDP_PORT_8BIT_SRC:
udp.src_port = LOWPAN_PORT_8BIT_OFFSET + tvb_get_guint8(tvb, offset);
udp.dst_port = tvb_get_ntohs(tvb, offset + 1);
src_bitlen = 8;
dst_bitlen = 16;
break;
case LOWPAN_NHC_UDP_PORT_12BIT:
udp.src_port = LOWPAN_PORT_12BIT_OFFSET + (tvb_get_guint8(tvb, offset) >> 4);
udp.dst_port = LOWPAN_PORT_12BIT_OFFSET + (tvb_get_guint8(tvb, offset) & 0x0f);
src_bitlen = 4;
dst_bitlen = 4;
break;
default:
DISSECTOR_ASSERT_NOT_REACHED();
break;
} /* switch */
proto_tree_add_uint(tree, hf_6lowpan_udp_src, tvb, offset, BITS_TO_BYTE_LEN(offset<<3, src_bitlen), udp.src_port);
@ -2704,12 +2718,9 @@ proto_register_6lowpan(void)
{ &hf_6lowpan_nhc_udp_checksum,
{ "Checksum", "6lowpan.nhc.udp.checksum",
FT_BOOLEAN, 8, TFS(&lowpan_compression), LOWPAN_NHC_UDP_CHECKSUM, NULL, HFILL }},
{ &hf_6lowpan_nhc_udp_src,
{ "Source port", "6lowpan.nhc.udp.src",
FT_BOOLEAN, 8, TFS(&lowpan_compression), LOWPAN_NHC_UDP_SRCPORT, NULL, HFILL }},
{ &hf_6lowpan_nhc_udp_dst,
{ "Destination port", "6lowpan.nhc.udp.dst",
FT_BOOLEAN, 8, TFS(&lowpan_compression), LOWPAN_NHC_UDP_DSTPORT, NULL, HFILL }},
{ &hf_6lowpan_nhc_udp_ports,
{ "Ports", "6lowpan.nhc.udp.ports",
FT_UINT8, BASE_DEC, VALS(lowpan_udp_ports), LOWPAN_NHC_UDP_PORTS, NULL, HFILL }},
/* Uncompressed IPv6 fields. */
{ &hf_6lowpan_traffic_class,