Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
afe00251 AB |
2 | #ifndef _DCCP_FEAT_H |
3 | #define _DCCP_FEAT_H | |
4 | /* | |
5 | * net/dccp/feat.h | |
6 | * | |
63b8e286 GR |
7 | * Feature negotiation for the DCCP protocol (RFC 4340, section 6) |
8 | * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk> | |
afe00251 | 9 | * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk> |
afe00251 | 10 | */ |
afe00251 | 11 | #include <linux/types.h> |
c02fdc0e | 12 | #include "dccp.h" |
afe00251 | 13 | |
e8ef967a GR |
14 | /* |
15 | * Known limit values | |
16 | */ | |
17 | /* Ack Ratio takes 2-byte integer values (11.3) */ | |
18 | #define DCCPF_ACK_RATIO_MAX 0xFFFF | |
19 | /* Wmin=32 and Wmax=2^46-1 from 7.5.2 */ | |
20 | #define DCCPF_SEQ_WMIN 32 | |
21 | #define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull | |
b20a9c24 GR |
22 | /* Maximum number of SP values that fit in a single (Confirm) option */ |
23 | #define DCCP_FEAT_MAX_SP_VALS (DCCP_SINGLE_OPT_MAXLEN - 2) | |
e8ef967a | 24 | |
bd012f2e GR |
25 | enum dccp_feat_type { |
26 | FEAT_AT_RX = 1, /* located at RX side of half-connection */ | |
27 | FEAT_AT_TX = 2, /* located at TX side of half-connection */ | |
28 | FEAT_SP = 4, /* server-priority reconciliation (6.3.1) */ | |
29 | FEAT_NN = 8, /* non-negotiable reconciliation (6.3.2) */ | |
30 | FEAT_UNKNOWN = 0xFF /* not understood or invalid feature */ | |
31 | }; | |
32 | ||
33 | enum dccp_feat_state { | |
34 | FEAT_DEFAULT = 0, /* using default values from 6.4 */ | |
35 | FEAT_INITIALISING, /* feature is being initialised */ | |
36 | FEAT_CHANGING, /* Change sent but not confirmed yet */ | |
37 | FEAT_UNSTABLE, /* local modification in state CHANGING */ | |
38 | FEAT_STABLE /* both ends (think they) agree */ | |
39 | }; | |
40 | ||
41 | /** | |
42 | * dccp_feat_val - Container for SP or NN feature values | |
43 | * @nn: single NN value | |
44 | * @sp.vec: single SP value plus optional preference list | |
45 | * @sp.len: length of @sp.vec in bytes | |
46 | */ | |
47 | typedef union { | |
48 | u64 nn; | |
49 | struct { | |
50 | u8 *vec; | |
51 | u8 len; | |
52 | } sp; | |
53 | } dccp_feat_val; | |
54 | ||
55 | /** | |
56 | * struct feat_entry - Data structure to perform feature negotiation | |
57 | * @val: feature's current value (SP features may have preference list) | |
58 | * @state: feature's current state | |
59 | * @feat_num: one of %dccp_feature_numbers | |
60 | * @needs_mandatory: whether Mandatory options should be sent | |
61 | * @needs_confirm: whether to send a Confirm instead of a Change | |
62 | * @empty_confirm: whether to send an empty Confirm (depends on @needs_confirm) | |
63 | * @is_local: feature location (1) or feature-remote (0) | |
64 | * @node: list pointers, entries arranged in FIFO order | |
65 | */ | |
66 | struct dccp_feat_entry { | |
67 | dccp_feat_val val; | |
68 | enum dccp_feat_state state:8; | |
69 | u8 feat_num; | |
70 | ||
71 | bool needs_mandatory, | |
72 | needs_confirm, | |
73 | empty_confirm, | |
74 | is_local; | |
75 | ||
76 | struct list_head node; | |
77 | }; | |
78 | ||
79 | static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry) | |
80 | { | |
81 | if (entry->needs_confirm) | |
82 | return entry->is_local ? DCCPO_CONFIRM_L : DCCPO_CONFIRM_R; | |
83 | return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R; | |
84 | } | |
85 | ||
e8ef967a GR |
86 | /** |
87 | * struct ccid_dependency - Track changes resulting from choosing a CCID | |
88 | * @dependent_feat: one of %dccp_feature_numbers | |
89 | * @is_local: local (1) or remote (0) @dependent_feat | |
90 | * @is_mandatory: whether presence of @dependent_feat is mission-critical or not | |
91 | * @val: corresponding default value for @dependent_feat (u8 is sufficient here) | |
92 | */ | |
93 | struct ccid_dependency { | |
94 | u8 dependent_feat; | |
95 | bool is_local:1, | |
96 | is_mandatory:1; | |
97 | u8 val; | |
98 | }; | |
99 | ||
883ca833 GR |
100 | /* |
101 | * Sysctls to seed defaults for feature negotiation | |
102 | */ | |
103 | extern unsigned long sysctl_dccp_sequence_window; | |
104 | extern int sysctl_dccp_rx_ccid; | |
105 | extern int sysctl_dccp_tx_ccid; | |
106 | ||
a402a5aa JP |
107 | int dccp_feat_init(struct sock *sk); |
108 | void dccp_feat_initialise_sysctls(void); | |
109 | int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local, | |
110 | u8 const *list, u8 len); | |
111 | int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *, | |
112 | u8 mand, u8 opt, u8 feat, u8 *val, u8 len); | |
113 | int dccp_feat_clone_list(struct list_head const *, struct list_head *); | |
afe00251 | 114 | |
02fa460e GR |
115 | /* |
116 | * Encoding variable-length options and their maximum length. | |
117 | * | |
118 | * This affects NN options (SP options are all u8) and other variable-length | |
119 | * options (see table 3 in RFC 4340). The limit is currently given the Sequence | |
120 | * Window NN value (sec. 7.5.2) and the NDP count (sec. 7.7) option, all other | |
121 | * options consume less than 6 bytes (timestamps are 4 bytes). | |
122 | * When updating this constant (e.g. due to new internet drafts / RFCs), make | |
123 | * sure that you also update all code which refers to it. | |
124 | */ | |
125 | #define DCCP_OPTVAL_MAXLEN 6 | |
126 | ||
a402a5aa JP |
127 | void dccp_encode_value_var(const u64 value, u8 *to, const u8 len); |
128 | u64 dccp_decode_value_var(const u8 *bf, const u8 len); | |
129 | u64 dccp_feat_nn_get(struct sock *sk, u8 feat); | |
d3710566 | 130 | |
a402a5aa JP |
131 | int dccp_insert_option_mandatory(struct sk_buff *skb); |
132 | int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, u8 *val, u8 len, | |
133 | bool repeat_first); | |
afe00251 | 134 | #endif /* _DCCP_FEAT_H */ |