1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _UAPI_LINUX_DCCP_H
3#define _UAPI_LINUX_DCCP_H
4
5#include <linux/types.h>
6#include <asm/byteorder.h>
7
8/**
9 * struct dccp_hdr - generic part of DCCP packet header
10 *
11 * @dccph_sport - Relevant port on the endpoint that sent this packet
12 * @dccph_dport - Relevant port on the other endpoint
13 * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
14 * @dccph_ccval - Used by the HC-Sender CCID
15 * @dccph_cscov - Parts of the packet that are covered by the Checksum field
16 * @dccph_checksum - Internet checksum, depends on dccph_cscov
17 * @dccph_x - 0 = 24 bit sequence number, 1 = 48
18 * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
19 * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
20 */
21struct dccp_hdr {
22	__be16	dccph_sport,
23		dccph_dport;
24	__u8	dccph_doff;
25#if defined(__LITTLE_ENDIAN_BITFIELD)
26	__u8	dccph_cscov:4,
27		dccph_ccval:4;
28#elif defined(__BIG_ENDIAN_BITFIELD)
29	__u8	dccph_ccval:4,
30		dccph_cscov:4;
31#else
32#error  "Adjust your <asm/byteorder.h> defines"
33#endif
34	__sum16	dccph_checksum;
35#if defined(__LITTLE_ENDIAN_BITFIELD)
36	__u8	dccph_x:1,
37		dccph_type:4,
38		dccph_reserved:3;
39#elif defined(__BIG_ENDIAN_BITFIELD)
40	__u8	dccph_reserved:3,
41		dccph_type:4,
42		dccph_x:1;
43#else
44#error  "Adjust your <asm/byteorder.h> defines"
45#endif
46	__u8	dccph_seq2;
47	__be16	dccph_seq;
48};
49
50/**
51 * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
52 *
53 * @dccph_seq_low - low 24 bits of a 48 bit seq packet
54 */
55struct dccp_hdr_ext {
56	__be32	dccph_seq_low;
57};
58
59/**
60 * struct dccp_hdr_request - Connection initiation request header
61 *
62 * @dccph_req_service - Service to which the client app wants to connect
63 */
64struct dccp_hdr_request {
65	__be32	dccph_req_service;
66};
67/**
68 * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
69 *
70 * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
71 * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
72 */
73struct dccp_hdr_ack_bits {
74	__be16	dccph_reserved1;
75	__be16	dccph_ack_nr_high;
76	__be32	dccph_ack_nr_low;
77};
78/**
79 * struct dccp_hdr_response - Connection initiation response header
80 *
81 * @dccph_resp_ack - 48 bit Acknowledgment Number Subheader (5.3)
82 * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
83 */
84struct dccp_hdr_response {
85	struct dccp_hdr_ack_bits	dccph_resp_ack;
86	__be32				dccph_resp_service;
87};
88
89/**
90 * struct dccp_hdr_reset - Unconditionally shut down a connection
91 *
92 * @dccph_reset_ack - 48 bit Acknowledgment Number Subheader (5.6)
93 * @dccph_reset_code - one of %dccp_reset_codes
94 * @dccph_reset_data - the Data 1 ... Data 3 fields from 5.6
95 */
96struct dccp_hdr_reset {
97	struct dccp_hdr_ack_bits	dccph_reset_ack;
98	__u8				dccph_reset_code,
99					dccph_reset_data[3];
100};
101
102enum dccp_pkt_type {
103	DCCP_PKT_REQUEST = 0,
104	DCCP_PKT_RESPONSE,
105	DCCP_PKT_DATA,
106	DCCP_PKT_ACK,
107	DCCP_PKT_DATAACK,
108	DCCP_PKT_CLOSEREQ,
109	DCCP_PKT_CLOSE,
110	DCCP_PKT_RESET,
111	DCCP_PKT_SYNC,
112	DCCP_PKT_SYNCACK,
113	DCCP_PKT_INVALID,
114};
115
116#define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID
117
118static inline unsigned int dccp_packet_hdr_len(const __u8 type)
119{
120	if (type == DCCP_PKT_DATA)
121		return 0;
122	if (type == DCCP_PKT_DATAACK	||
123	    type == DCCP_PKT_ACK	||
124	    type == DCCP_PKT_SYNC	||
125	    type == DCCP_PKT_SYNCACK	||
126	    type == DCCP_PKT_CLOSE	||
127	    type == DCCP_PKT_CLOSEREQ)
128		return sizeof(struct dccp_hdr_ack_bits);
129	if (type == DCCP_PKT_REQUEST)
130		return sizeof(struct dccp_hdr_request);
131	if (type == DCCP_PKT_RESPONSE)
132		return sizeof(struct dccp_hdr_response);
133	return sizeof(struct dccp_hdr_reset);
134}
135enum dccp_reset_codes {
136	DCCP_RESET_CODE_UNSPECIFIED = 0,
137	DCCP_RESET_CODE_CLOSED,
138	DCCP_RESET_CODE_ABORTED,
139	DCCP_RESET_CODE_NO_CONNECTION,
140	DCCP_RESET_CODE_PACKET_ERROR,
141	DCCP_RESET_CODE_OPTION_ERROR,
142	DCCP_RESET_CODE_MANDATORY_ERROR,
143	DCCP_RESET_CODE_CONNECTION_REFUSED,
144	DCCP_RESET_CODE_BAD_SERVICE_CODE,
145	DCCP_RESET_CODE_TOO_BUSY,
146	DCCP_RESET_CODE_BAD_INIT_COOKIE,
147	DCCP_RESET_CODE_AGGRESSION_PENALTY,
148
149	DCCP_MAX_RESET_CODES		/* Leave at the end!  */
150};
151
152/* DCCP options */
153enum {
154	DCCPO_PADDING = 0,
155	DCCPO_MANDATORY = 1,
156	DCCPO_MIN_RESERVED = 3,
157	DCCPO_MAX_RESERVED = 31,
158	DCCPO_CHANGE_L = 32,
159	DCCPO_CONFIRM_L = 33,
160	DCCPO_CHANGE_R = 34,
161	DCCPO_CONFIRM_R = 35,
162	DCCPO_NDP_COUNT = 37,
163	DCCPO_ACK_VECTOR_0 = 38,
164	DCCPO_ACK_VECTOR_1 = 39,
165	DCCPO_TIMESTAMP = 41,
166	DCCPO_TIMESTAMP_ECHO = 42,
167	DCCPO_ELAPSED_TIME = 43,
168	DCCPO_MAX = 45,
169	DCCPO_MIN_RX_CCID_SPECIFIC = 128,	/* from sender to receiver */
170	DCCPO_MAX_RX_CCID_SPECIFIC = 191,
171	DCCPO_MIN_TX_CCID_SPECIFIC = 192,	/* from receiver to sender */
172	DCCPO_MAX_TX_CCID_SPECIFIC = 255,
173};
174/* maximum size of a single TLV-encoded DCCP option (sans type/len bytes) */
175#define DCCP_SINGLE_OPT_MAXLEN	253
176
177/* DCCP CCIDS */
178enum {
179	DCCPC_CCID2 = 2,
180	DCCPC_CCID3 = 3,
181};
182
183/* DCCP features (RFC 4340 section 6.4) */
184enum dccp_feature_numbers {
185	DCCPF_RESERVED = 0,
186	DCCPF_CCID = 1,
187	DCCPF_SHORT_SEQNOS = 2,
188	DCCPF_SEQUENCE_WINDOW = 3,
189	DCCPF_ECN_INCAPABLE = 4,
190	DCCPF_ACK_RATIO = 5,
191	DCCPF_SEND_ACK_VECTOR = 6,
192	DCCPF_SEND_NDP_COUNT = 7,
193	DCCPF_MIN_CSUM_COVER = 8,
194	DCCPF_DATA_CHECKSUM = 9,
195	/* 10-127 reserved */
196	DCCPF_MIN_CCID_SPECIFIC = 128,
197	DCCPF_SEND_LEV_RATE = 192,	/* RFC 4342, sec. 8.4 */
198	DCCPF_MAX_CCID_SPECIFIC = 255,
199};
200
201/* DCCP socket control message types for cmsg */
202enum dccp_cmsg_type {
203	DCCP_SCM_PRIORITY = 1,
204	DCCP_SCM_QPOLICY_MAX = 0xFFFF,
205	/* ^-- Up to here reserved exclusively for qpolicy parameters */
206	DCCP_SCM_MAX
207};
208
209/* DCCP priorities for outgoing/queued packets */
210enum dccp_packet_dequeueing_policy {
211	DCCPQ_POLICY_SIMPLE,
212	DCCPQ_POLICY_PRIO,
213	DCCPQ_POLICY_MAX
214};
215
216/* DCCP socket options */
217#define DCCP_SOCKOPT_PACKET_SIZE	1 /* XXX deprecated, without effect */
218#define DCCP_SOCKOPT_SERVICE		2
219#define DCCP_SOCKOPT_CHANGE_L		3
220#define DCCP_SOCKOPT_CHANGE_R		4
221#define DCCP_SOCKOPT_GET_CUR_MPS	5
222#define DCCP_SOCKOPT_SERVER_TIMEWAIT	6
223#define DCCP_SOCKOPT_SEND_CSCOV		10
224#define DCCP_SOCKOPT_RECV_CSCOV		11
225#define DCCP_SOCKOPT_AVAILABLE_CCIDS	12
226#define DCCP_SOCKOPT_CCID		13
227#define DCCP_SOCKOPT_TX_CCID		14
228#define DCCP_SOCKOPT_RX_CCID		15
229#define DCCP_SOCKOPT_QPOLICY_ID		16
230#define DCCP_SOCKOPT_QPOLICY_TXQLEN	17
231#define DCCP_SOCKOPT_CCID_RX_INFO	128
232#define DCCP_SOCKOPT_CCID_TX_INFO	192
233
234/* maximum number of services provided on the same listening port */
235#define DCCP_SERVICE_LIST_MAX_LEN      32
236
237
238#endif /* _UAPI_LINUX_DCCP_H */
239