135 lines
4.4 KiB
C
135 lines
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
#ifndef _DCCP_FEAT_H
|
|
#define _DCCP_FEAT_H
|
|
/*
|
|
* net/dccp/feat.h
|
|
*
|
|
* Feature negotiation for the DCCP protocol (RFC 4340, section 6)
|
|
* Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk>
|
|
* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
|
|
*/
|
|
#include <linux/types.h>
|
|
#include "dccp.h"
|
|
|
|
/*
|
|
* Known limit values
|
|
*/
|
|
/* Ack Ratio takes 2-byte integer values (11.3) */
|
|
#define DCCPF_ACK_RATIO_MAX 0xFFFF
|
|
/* Wmin=32 and Wmax=2^46-1 from 7.5.2 */
|
|
#define DCCPF_SEQ_WMIN 32
|
|
#define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull
|
|
/* Maximum number of SP values that fit in a single (Confirm) option */
|
|
#define DCCP_FEAT_MAX_SP_VALS (DCCP_SINGLE_OPT_MAXLEN - 2)
|
|
|
|
enum dccp_feat_type {
|
|
FEAT_AT_RX = 1, /* located at RX side of half-connection */
|
|
FEAT_AT_TX = 2, /* located at TX side of half-connection */
|
|
FEAT_SP = 4, /* server-priority reconciliation (6.3.1) */
|
|
FEAT_NN = 8, /* non-negotiable reconciliation (6.3.2) */
|
|
FEAT_UNKNOWN = 0xFF /* not understood or invalid feature */
|
|
};
|
|
|
|
enum dccp_feat_state {
|
|
FEAT_DEFAULT = 0, /* using default values from 6.4 */
|
|
FEAT_INITIALISING, /* feature is being initialised */
|
|
FEAT_CHANGING, /* Change sent but not confirmed yet */
|
|
FEAT_UNSTABLE, /* local modification in state CHANGING */
|
|
FEAT_STABLE /* both ends (think they) agree */
|
|
};
|
|
|
|
/**
|
|
* dccp_feat_val - Container for SP or NN feature values
|
|
* @nn: single NN value
|
|
* @sp.vec: single SP value plus optional preference list
|
|
* @sp.len: length of @sp.vec in bytes
|
|
*/
|
|
typedef union {
|
|
u64 nn;
|
|
struct {
|
|
u8 *vec;
|
|
u8 len;
|
|
} sp;
|
|
} dccp_feat_val;
|
|
|
|
/**
|
|
* struct feat_entry - Data structure to perform feature negotiation
|
|
* @val: feature's current value (SP features may have preference list)
|
|
* @state: feature's current state
|
|
* @feat_num: one of %dccp_feature_numbers
|
|
* @needs_mandatory: whether Mandatory options should be sent
|
|
* @needs_confirm: whether to send a Confirm instead of a Change
|
|
* @empty_confirm: whether to send an empty Confirm (depends on @needs_confirm)
|
|
* @is_local: feature location (1) or feature-remote (0)
|
|
* @node: list pointers, entries arranged in FIFO order
|
|
*/
|
|
struct dccp_feat_entry {
|
|
dccp_feat_val val;
|
|
enum dccp_feat_state state:8;
|
|
u8 feat_num;
|
|
|
|
bool needs_mandatory,
|
|
needs_confirm,
|
|
empty_confirm,
|
|
is_local;
|
|
|
|
struct list_head node;
|
|
};
|
|
|
|
static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry)
|
|
{
|
|
if (entry->needs_confirm)
|
|
return entry->is_local ? DCCPO_CONFIRM_L : DCCPO_CONFIRM_R;
|
|
return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R;
|
|
}
|
|
|
|
/**
|
|
* struct ccid_dependency - Track changes resulting from choosing a CCID
|
|
* @dependent_feat: one of %dccp_feature_numbers
|
|
* @is_local: local (1) or remote (0) @dependent_feat
|
|
* @is_mandatory: whether presence of @dependent_feat is mission-critical or not
|
|
* @val: corresponding default value for @dependent_feat (u8 is sufficient here)
|
|
*/
|
|
struct ccid_dependency {
|
|
u8 dependent_feat;
|
|
bool is_local:1,
|
|
is_mandatory:1;
|
|
u8 val;
|
|
};
|
|
|
|
/*
|
|
* Sysctls to seed defaults for feature negotiation
|
|
*/
|
|
extern unsigned long sysctl_dccp_sequence_window;
|
|
extern int sysctl_dccp_rx_ccid;
|
|
extern int sysctl_dccp_tx_ccid;
|
|
|
|
int dccp_feat_init(struct sock *sk);
|
|
void dccp_feat_initialise_sysctls(void);
|
|
int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
|
|
u8 const *list, u8 len);
|
|
int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
|
|
u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
|
|
int dccp_feat_clone_list(struct list_head const *, struct list_head *);
|
|
|
|
/*
|
|
* Encoding variable-length options and their maximum length.
|
|
*
|
|
* This affects NN options (SP options are all u8) and other variable-length
|
|
* options (see table 3 in RFC 4340). The limit is currently given the Sequence
|
|
* Window NN value (sec. 7.5.2) and the NDP count (sec. 7.7) option, all other
|
|
* options consume less than 6 bytes (timestamps are 4 bytes).
|
|
* When updating this constant (e.g. due to new internet drafts / RFCs), make
|
|
* sure that you also update all code which refers to it.
|
|
*/
|
|
#define DCCP_OPTVAL_MAXLEN 6
|
|
|
|
void dccp_encode_value_var(const u64 value, u8 *to, const u8 len);
|
|
u64 dccp_decode_value_var(const u8 *bf, const u8 len);
|
|
u64 dccp_feat_nn_get(struct sock *sk, u8 feat);
|
|
|
|
int dccp_insert_option_mandatory(struct sk_buff *skb);
|
|
int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, u8 *val, u8 len,
|
|
bool repeat_first);
|
|
#endif /* _DCCP_FEAT_H */
|