fade756f18
With this patch, TX/RX CCIDs can now be changed on a per-connection basis, which overrides the defaults set by the global sysctl variables for TX/RX CCIDs. To make full use of this facility, the remaining patches of this patch set are needed, which track dependencies and activate negotiated feature values. Note on the maximum number of CCIDs that can be registered: ----------------------------------------------------------- The maximum number of CCIDs that can be registered on the socket is constrained by the space in a Confirm/Change feature negotiation option. The space in these in turn depends on the size of header options as defined in RFC 4340, 5.8. Since this is a recurring constant, it has been moved from ackvec.h into linux/dccp.h, clarifying its purpose. Relative to this size, the maximum number of CCID identifiers that can be present in a Confirm option (which always consumes 1 byte more than a Change option, cf. 6.1) is 2 bytes less than the maximum TLV size: one for the CCID-feature-type and one for the selected value. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
128 lines
4.1 KiB
C
128 lines
4.1 KiB
C
#ifndef _DCCP_FEAT_H
|
|
#define _DCCP_FEAT_H
|
|
/*
|
|
* net/dccp/feat.h
|
|
*
|
|
* An implementation of the DCCP protocol
|
|
* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#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
|
|
* @feat_num: one of %dccp_feature_numbers
|
|
* @val: feature's current value (SP features may have preference list)
|
|
* @state: feature's current state
|
|
* @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 {
|
|
u8 feat_num;
|
|
dccp_feat_val val;
|
|
enum dccp_feat_state state:8;
|
|
bool needs_mandatory:1,
|
|
needs_confirm:1,
|
|
empty_confirm:1,
|
|
is_local:1;
|
|
|
|
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;
|
|
};
|
|
|
|
#ifdef CONFIG_IP_DCCP_DEBUG
|
|
extern const char *dccp_feat_typename(const u8 type);
|
|
extern const char *dccp_feat_name(const u8 feat);
|
|
|
|
static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)
|
|
{
|
|
dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type),
|
|
dccp_feat_name(feat), feat, val);
|
|
}
|
|
#else
|
|
#define dccp_feat_debug(type, feat, val)
|
|
#endif /* CONFIG_IP_DCCP_DEBUG */
|
|
|
|
extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
|
|
u8 const *list, u8 len);
|
|
extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
|
|
extern int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature,
|
|
u8 *val, u8 len);
|
|
extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
|
|
u8 *val, u8 len);
|
|
extern void dccp_feat_clean(struct dccp_minisock *dmsk);
|
|
extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
|
|
extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
|
|
extern int dccp_feat_init(struct sock *sk);
|
|
|
|
#endif /* _DCCP_FEAT_H */
|