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  */
21 struct 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  */
55 struct 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  */
64 struct 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  */
73 struct 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  */
84 struct 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  */
96 struct dccp_hdr_reset {
97 	struct dccp_hdr_ack_bits	dccph_reset_ack;
98 	__u8				dccph_reset_code,
99 					dccph_reset_data[3];
100 };
101 
102 enum 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 
dccp_packet_hdr_len(const __u8 type)118 static 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 }
135 enum 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 */
153 enum {
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 */
178 enum {
179 	DCCPC_CCID2 = 2,
180 	DCCPC_CCID3 = 3,
181 };
182 
183 /* DCCP features (RFC 4340 section 6.4) */
184 enum 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 */
202 enum 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 */
210 enum 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