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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001 Intel Corp.
*
* This file is part of the SCTP kernel implementation
*
* Please send any bug reports or fixes you make to the
* email addresses:
* lksctp developers <[email protected]>
*
* Written or modified by:
* Randall Stewart <[email protected]>
* Ken Morneau <[email protected]>
* Qiaobing Xie <[email protected]>
* La Monte H.P. Yarroll <[email protected]>
* Karl Knutson <[email protected]>
* Jon Grimm <[email protected]>
* Xingang Guo <[email protected]>
* Hui Huang <[email protected]>
* Sridhar Samudrala <[email protected]>
* Daisy Chang <[email protected]>
* Dajiang Zhang <[email protected]>
* Ardelle Fan <[email protected]>
* Ryan Layer <[email protected]>
* Anup Pemmaiah <[email protected]>
* Kevin Gao <[email protected]>
*/
#ifndef __sctp_structs_h__
#define __sctp_structs_h__
#include <linux/ktime.h>
#include <linux/generic-radix-tree.h>
#include <linux/rhashtable-types.h>
#include <linux/socket.h> /* linux/in.h needs this!! */
#include <linux/in.h> /* We get struct sockaddr_in. */
#include <linux/in6.h> /* We get struct in6_addr */
#include <linux/ipv6.h>
#include <asm/param.h> /* We get MAXHOSTNAMELEN. */
#include <linux/atomic.h> /* This gets us atomic counters. */
#include <linux/skbuff.h> /* We need sk_buff_head. */
#include <linux/workqueue.h> /* We need tq_struct. */
#include <linux/sctp.h> /* We need sctp* header structs. */
#include <net/sctp/auth.h> /* We need auth specific structs */
#include <net/ip.h> /* For inet_skb_parm */
/* A convenience structure for handling sockaddr structures.
* We should wean ourselves off this.
*/
union sctp_addr {
struct sockaddr_in v4;
struct sockaddr_in6 v6;
struct sockaddr sa;
};
/* Forward declarations for data structures. */
struct sctp_globals;
struct sctp_endpoint;
struct sctp_association;
struct sctp_transport;
struct sctp_packet;
struct sctp_chunk;
struct sctp_inq;
struct sctp_outq;
struct sctp_bind_addr;
struct sctp_ulpq;
struct sctp_ep_common;
struct crypto_shash;
struct sctp_stream;
#include <net/sctp/tsnmap.h>
#include <net/sctp/ulpevent.h>
#include <net/sctp/ulpqueue.h>
#include <net/sctp/stream_interleave.h>
/* Structures useful for managing bind/connect. */
struct sctp_bind_bucket {
unsigned short port;
signed char fastreuse;
signed char fastreuseport;
kuid_t fastuid;
struct hlist_node node;
struct hlist_head owner;
struct net *net;
};
struct sctp_bind_hashbucket {
spinlock_t lock;
struct hlist_head chain;
};
/* Used for hashing all associations. */
struct sctp_hashbucket {
rwlock_t lock;
struct hlist_head chain;
} __attribute__((__aligned__(8)));
/* The SCTP globals structure. */
extern struct sctp_globals {
/* This is a list of groups of functions for each address
* family that we support.
*/
struct list_head address_families;
/* This is the hash of all endpoints. */
struct sctp_hashbucket *ep_hashtable;
/* This is the sctp port control hash. */
struct sctp_bind_hashbucket *port_hashtable;
/* This is the hash of all transports. */
struct rhltable transport_hashtable;
/* Sizes of above hashtables. */
int ep_hashsize;
int port_hashsize;
/* Default initialization values to be applied to new associations. */
__u16 max_instreams;
__u16 max_outstreams;
/* Flag to indicate whether computing and verifying checksum
* is disabled. */
bool checksum_disable;
} sctp_globals;
#define sctp_max_instreams (sctp_globals.max_instreams)
#define sctp_max_outstreams (sctp_globals.max_outstreams)
#define sctp_address_families (sctp_globals.address_families)
#define sctp_ep_hashsize (sctp_globals.ep_hashsize)
#define sctp_ep_hashtable (sctp_globals.ep_hashtable)
#define sctp_port_hashsize (sctp_globals.port_hashsize)
#define sctp_port_hashtable (sctp_globals.port_hashtable)
#define sctp_transport_hashtable (sctp_globals.transport_hashtable)
#define sctp_checksum_disable (sctp_globals.checksum_disable)
/* SCTP Socket type: UDP or TCP style. */
enum sctp_socket_type {
SCTP_SOCKET_UDP = 0,
SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
SCTP_SOCKET_TCP
};
/* Per socket SCTP information. */
struct sctp_sock {
/* inet_sock has to be the first member of sctp_sock */
struct inet_sock inet;
/* What kind of a socket is this? */
enum sctp_socket_type type;
/* PF_ family specific functions. */
struct sctp_pf *pf;
/* Access to HMAC transform. */
struct crypto_shash *hmac;
char *sctp_hmac_alg;
/* What is our base endpointer? */
struct sctp_endpoint *ep;
struct sctp_bind_bucket *bind_hash;
/* Various Socket Options. */
__u16 default_stream;
__u32 default_ppid;
__u16 default_flags;
__u32 default_context;
__u32 default_timetolive;
__u32 default_rcv_context;
int max_burst;
/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
* the destination address every heartbeat interval. This value
* will be inherited by all new associations.
*/
__u32 hbinterval;
__be16 udp_port;
__be16 encap_port;
/* This is the max_retrans value for new associations. */
__u16 pathmaxrxt;
__u32 flowlabel;
__u8 dscp;
__u16 pf_retrans;
__u16 ps_retrans;
/* The initial Path MTU to use for new associations. */
__u32 pathmtu;
/* The default SACK delay timeout for new associations. */
__u32 sackdelay;
__u32 sackfreq;
/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
__u32 param_flags;
__u32 default_ss;
struct sctp_rtoinfo rtoinfo;
struct sctp_paddrparams paddrparam;
struct sctp_assocparams assocparams;
/*
* These two structures must be grouped together for the usercopy
* whitelist region.
*/
__u16 subscribe;
struct sctp_initmsg initmsg;
int user_frag;
__u32 autoclose;
__u32 adaptation_ind;
__u32 pd_point;
__u16 nodelay:1,
pf_expose:2,
reuse:1,
disable_fragments:1,
v4mapped:1,
frag_interleave:1,
recvrcvinfo:1,
recvnxtinfo:1,
data_ready_signalled:1;
atomic_t pd_mode;
/* Fields after this point will be skipped on copies, like on accept
* and peeloff operations
*/
/* Receive to here while partial delivery is in effect. */
struct sk_buff_head pd_lobby;
struct list_head auto_asconf_list;
int do_auto_asconf;
};
static inline struct sctp_sock *sctp_sk(const struct sock *sk)
{
return (struct sctp_sock *)sk;
}
static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
{
return (struct sock *)sp;
}
#if IS_ENABLED(CONFIG_IPV6)
struct sctp6_sock {
struct sctp_sock sctp;
struct ipv6_pinfo inet6;
};
#endif /* CONFIG_IPV6 */
/* This is our APPLICATION-SPECIFIC state cookie.
* THIS IS NOT DICTATED BY THE SPECIFICATION.
*/
/* These are the parts of an association which we send in the cookie.
* Most of these are straight out of:
* RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
*
*/
struct sctp_cookie {
/* My : Tag expected in every inbound packet and sent
* Verification: in the INIT or INIT ACK chunk.
* Tag :
*/
__u32 my_vtag;
/* Peer's : Tag expected in every outbound packet except
* Verification: in the INIT chunk.
* Tag :
*/
__u32 peer_vtag;
/* The rest of these are not from the spec, but really need to
* be in the cookie.
*/
/* My Tie Tag : Assist in discovering a restarting association. */
__u32 my_ttag;
/* Peer's Tie Tag: Assist in discovering a restarting association. */
__u32 peer_ttag;
/* When does this cookie expire? */
ktime_t expiration;
/* Number of inbound/outbound streams which are set
* and negotiated during the INIT process.
*/
__u16 sinit_num_ostreams;
__u16 sinit_max_instreams;
/* This is the first sequence number I used. */
__u32 initial_tsn;
/* This holds the originating address of the INIT packet. */
union sctp_addr peer_addr;
/* IG Section 2.35.3
* Include the source port of the INIT-ACK
*/
__u16 my_port;
__u8 prsctp_capable;
/* Padding for future use */
__u8 padding;
__u32 adaptation_ind;
__u8 auth_random[sizeof(struct sctp_paramhdr) +
SCTP_AUTH_RANDOM_LENGTH];
__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
/* This is a shim for my peer's INIT packet, followed by
* a copy of the raw address list of the association.
* The length of the raw address list is saved in the
* raw_addr_list_len field, which will be used at the time when
* the association TCB is re-constructed from the cookie.
*/
__u32 raw_addr_list_len;
struct sctp_init_chunk peer_init[];
};
/* The format of our cookie that we send to our peer. */
struct sctp_signed_cookie {
__u8 signature[SCTP_SECRET_SIZE];
__u32 __pad; /* force sctp_cookie alignment to 64 bits */
struct sctp_cookie c;
} __packed;
/* This is another convenience type to allocate memory for address
* params for the maximum size and pass such structures around
* internally.
*/
union sctp_addr_param {
struct sctp_paramhdr p;
struct sctp_ipv4addr_param v4;
struct sctp_ipv6addr_param v6;
};
/* A convenience type to allow walking through the various
* parameters and avoid casting all over the place.
*/
union sctp_params {
void *v;
struct sctp_paramhdr *p;
struct sctp_cookie_preserve_param *life;
struct sctp_hostname_param *dns;
struct sctp_cookie_param *cookie;
struct sctp_supported_addrs_param *sat;
struct sctp_ipv4addr_param *v4;
struct sctp_ipv6addr_param *v6;
union sctp_addr_param *addr;
struct sctp_adaptation_ind_param *aind;
struct sctp_supported_ext_param *ext;
struct sctp_random_param *random;
struct sctp_chunks_param *chunks;
struct sctp_hmac_algo_param *hmac_algo;
struct sctp_addip_param *addip;
};
/* RFC 2960. Section 3.3.5 Heartbeat.
* Heartbeat Information: variable length
* The Sender-specific Heartbeat Info field should normally include
* information about the sender's current time when this HEARTBEAT
* chunk is sent and the destination transport address to which this
* HEARTBEAT is sent (see Section 8.3).
*/
struct sctp_sender_hb_info {
struct sctp_paramhdr param_hdr;
union sctp_addr daddr;
unsigned long sent_at;
__u64 hb_nonce;
};
int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
gfp_t gfp);
int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
void sctp_stream_free(struct sctp_stream *stream);
void sctp_stream_clear(struct sctp_stream *stream);
void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
/* What is the current SSN number for this stream? */
#define sctp_ssn_peek(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->ssn)
/* Return the next SSN number for this stream. */
#define sctp_ssn_next(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->ssn++)
/* Skip over this ssn and all below. */
#define sctp_ssn_skip(stream, type, sid, ssn) \
(sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
/* What is the current MID number for this stream? */
#define sctp_mid_peek(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->mid)
/* Return the next MID number for this stream. */
#define sctp_mid_next(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->mid++)
/* Skip over this mid and all below. */
#define sctp_mid_skip(stream, type, sid, mid) \
(sctp_stream_##type((stream), (sid))->mid = mid + 1)
/* What is the current MID_uo number for this stream? */
#define sctp_mid_uo_peek(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->mid_uo)
/* Return the next MID_uo number for this stream. */
#define sctp_mid_uo_next(stream, type, sid) \
(sctp_stream_##type((stream), (sid))->mid_uo++)
/*
* Pointers to address related SCTP functions.
* (i.e. things that depend on the address family.)
*/
struct sctp_af {
int (*sctp_xmit) (struct sk_buff *skb,
struct sctp_transport *);
int (*setsockopt) (struct sock *sk,
int level,
int optname,
sockptr_t optval,
unsigned int optlen);
int (*getsockopt) (struct sock *sk,
int level,
int optname,
char __user *optval,
int __user *optlen);
void (*get_dst) (struct sctp_transport *t,
union sctp_addr *saddr,
struct flowi *fl,
struct sock *sk);
void (*get_saddr) (struct sctp_sock *sk,
struct sctp_transport *t,
struct flowi *fl);
void (*copy_addrlist) (struct list_head *,
struct net_device *);
int (*cmp_addr) (const union sctp_addr *addr1,
const union sctp_addr *addr2);
void (*addr_copy) (union sctp_addr *dst,
union sctp_addr *src);
void (*from_skb) (union sctp_addr *,
struct sk_buff *skb,
int saddr);
void (*from_sk) (union sctp_addr *,
struct sock *sk);
bool (*from_addr_param) (union sctp_addr *,
union sctp_addr_param *,
__be16 port, int iif);
int (*to_addr_param) (const union sctp_addr *,
union sctp_addr_param *);
int (*addr_valid) (union sctp_addr *,
struct sctp_sock *,
const struct sk_buff *);
enum sctp_scope (*scope)(union sctp_addr *);
void (*inaddr_any) (union sctp_addr *, __be16);
int (*is_any) (const union sctp_addr *);
int (*available) (union sctp_addr *,
struct sctp_sock *);
int (*skb_iif) (const struct sk_buff *sk);
int (*is_ce) (const struct sk_buff *sk);
void (*seq_dump_addr)(struct seq_file *seq,
union sctp_addr *addr);
void (*ecn_capable)(struct sock *sk);
__u16 net_header_len;
int sockaddr_len;
int (*ip_options_len)(struct sock *sk);
sa_family_t sa_family;
struct list_head list;
};
struct sctp_af *sctp_get_af_specific(sa_family_t);
int sctp_register_af(struct sctp_af *);
/* Protocol family functions. */
struct sctp_pf {
void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
void (*skb_msgname) (struct sk_buff *, char *, int *);
int (*af_supported) (sa_family_t, struct sctp_sock *);
int (*cmp_addr) (const union sctp_addr *,
const union sctp_addr *,
struct sctp_sock *);
int (*bind_verify) (struct sctp_sock *, union sctp_addr *);
int (*send_verify) (struct sctp_sock *, union sctp_addr *);
int (*supported_addrs)(const struct sctp_sock *, __be16 *);
struct sock *(*create_accept_sk) (struct sock *sk,
struct sctp_association *asoc,
bool kern);
int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
struct sctp_af *af;
};
/* Structure to track chunk fragments that have been acked, but peer
* fragments of the same message have not.
*/
struct sctp_datamsg {
/* Chunks waiting to be submitted to lower layer. */
struct list_head chunks;
/* Reference counting. */
refcount_t refcnt;
/* When is this message no longer interesting to the peer? */
unsigned long expires_at;
/* Did the messenge fail to send? */
int send_error;
u8 send_failed:1,
can_delay:1, /* should this message be Nagle delayed */
abandoned:1; /* should this message be abandoned */
};
struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
struct sctp_sndrcvinfo *,
struct iov_iter *);
void sctp_datamsg_free(struct sctp_datamsg *);
void sctp_datamsg_put(struct sctp_datamsg *);
void sctp_chunk_fail(struct sctp_chunk *, int error);
int sctp_chunk_abandoned(struct sctp_chunk *);
/* RFC2960 1.4 Key Terms
*
* o Chunk: A unit of information within an SCTP packet, consisting of
* a chunk header and chunk-specific content.
*
* As a matter of convenience, we remember the SCTP common header for
* each chunk as well as a few other header pointers...
*/
struct sctp_chunk {
struct list_head list;
refcount_t refcnt;
/* How many times this chunk have been sent, for prsctp RTX policy */
int sent_count;
union {
/* This is our link to the per-transport transmitted list. */
struct list_head transmitted_list;
/* List in specific stream outq */
struct list_head stream_list;
};
/* This field is used by chunks that hold fragmented data.
* For the first fragment this is the list that holds the rest of
* fragments. For the remaining fragments, this is the link to the
* frag_list maintained in the first fragment.
*/
struct list_head frag_list;
/* This points to the sk_buff containing the actual data. */
struct sk_buff *skb;
union {
/* In case of GSO packets, this will store the head one */
struct sk_buff *head_skb;
/* In case of auth enabled, this will point to the shkey */
struct sctp_shared_key *shkey;
};
/* These are the SCTP headers by reverse order in a packet.
* Note that some of these may happen more than once. In that
* case, we point at the "current" one, whatever that means
* for that level of header.
*/
/* We point this at the FIRST TLV parameter to chunk_hdr. */
union sctp_params param_hdr;
union {
__u8 *v;
struct sctp_datahdr *data_hdr;
struct sctp_inithdr *init_hdr;
struct sctp_sackhdr *sack_hdr;
struct sctp_heartbeathdr *hb_hdr;
struct sctp_sender_hb_info *hbs_hdr;
struct sctp_shutdownhdr *shutdown_hdr;
struct sctp_signed_cookie *cookie_hdr;
struct sctp_ecnehdr *ecne_hdr;
struct sctp_cwrhdr *ecn_cwr_hdr;
struct sctp_errhdr *err_hdr;
struct sctp_addiphdr *addip_hdr;
struct sctp_fwdtsn_hdr *fwdtsn_hdr;
struct sctp_authhdr *auth_hdr;
struct sctp_idatahdr *idata_hdr;
struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
} subh;
__u8 *chunk_end;
struct sctp_chunkhdr *chunk_hdr;
struct sctphdr *sctp_hdr;
/* This needs to be recoverable for SCTP_SEND_FAILED events. */
struct sctp_sndrcvinfo sinfo;
/* Which association does this belong to? */
struct sctp_association *asoc;
/* What endpoint received this chunk? */
struct sctp_ep_common *rcvr;
/* We fill this in if we are calculating RTT. */
unsigned long sent_at;
/* What is the origin IP address for this chunk? */
union sctp_addr source;
/* Destination address for this chunk. */
union sctp_addr dest;
/* For outbound message, track all fragments for SEND_FAILED. */
struct sctp_datamsg *msg;
/* For an inbound chunk, this tells us where it came from.
* For an outbound chunk, it tells us where we'd like it to
* go. It is NULL if we have no preference.
*/
struct sctp_transport *transport;
/* SCTP-AUTH: For the special case inbound processing of COOKIE-ECHO
* we need save a pointer to the AUTH chunk, since the SCTP-AUTH
* spec violates the principle premis that all chunks are processed
* in order.
*/
struct sk_buff *auth_chunk;
#define SCTP_CAN_FRTX 0x0
#define SCTP_NEED_FRTX 0x1
#define SCTP_DONT_FRTX 0x2
__u16 rtt_in_progress:1, /* This chunk used for RTT calc? */
has_tsn:1, /* Does this chunk have a TSN yet? */
has_ssn:1, /* Does this chunk have a SSN yet? */
#define has_mid has_ssn
singleton:1, /* Only chunk in the packet? */
end_of_packet:1, /* Last chunk in the packet? */
ecn_ce_done:1, /* Have we processed the ECN CE bit? */
pdiscard:1, /* Discard the whole packet now? */
tsn_gap_acked:1, /* Is this chunk acked by a GAP ACK? */
data_accepted:1, /* At least 1 chunk accepted */
auth:1, /* IN: was auth'ed | OUT: needs auth */
has_asconf:1, /* IN: have seen an asconf before */
tsn_missing_report:2, /* Data chunk missing counter. */
fast_retransmit:2; /* Is this chunk fast retransmitted? */
};
#define sctp_chunk_retransmitted(chunk) (chunk->sent_count > 1)
void sctp_chunk_hold(struct sctp_chunk *);
void sctp_chunk_put(struct sctp_chunk *);
int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
struct iov_iter *from);
void sctp_chunk_free(struct sctp_chunk *);
void *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
struct sctp_chunk *sctp_chunkify(struct sk_buff *,
const struct sctp_association *,
struct sock *, gfp_t gfp);
void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
union sctp_addr *);
const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
{
return ntohs(ch->subh.data_hdr->stream);
}
enum {
SCTP_ADDR_NEW, /* new address added to assoc/ep */
SCTP_ADDR_SRC, /* address can be used as source */
SCTP_ADDR_DEL, /* address about to be deleted */
};
/* This is a structure for holding either an IPv6 or an IPv4 address. */
struct sctp_sockaddr_entry {
struct list_head list;
struct rcu_head rcu;
union sctp_addr a;
__u8 state;
__u8 valid;
};
#define SCTP_ADDRESS_TICK_DELAY 500
/* This structure holds lists of chunks as we are assembling for
* transmission.
*/
struct sctp_packet {
/* These are the SCTP header values (host order) for the packet. */
__u16 source_port;
__u16 destination_port;
__u32 vtag;
/* This contains the payload chunks. */
struct list_head chunk_list;
/* This is the overhead of the sctp and ip headers. */
size_t overhead;
/* This is the total size of all chunks INCLUDING padding. */
size_t size;
/* This is the maximum size this packet may have */
size_t max_size;
/* The packet is destined for this transport address.
* The function we finally use to pass down to the next lower
* layer lives in the transport structure.
*/
struct sctp_transport *transport;
/* pointer to the auth chunk for this packet */
struct sctp_chunk *auth;
u8 has_cookie_echo:1, /* This packet contains a COOKIE-ECHO chunk. */
has_sack:1, /* This packet contains a SACK chunk. */
has_auth:1, /* This packet contains an AUTH chunk */
has_data:1, /* This packet contains at least 1 DATA chunk */
ipfragok:1; /* So let ip fragment this packet */
};
void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
__u16 sport, __u16 dport);
void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk,
int one_packet, gfp_t gfp);
enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
struct sctp_chunk *chunk);
int sctp_packet_transmit(struct sctp_packet *, gfp_t);
void sctp_packet_free(struct sctp_packet *);
static inline int sctp_packet_empty(struct sctp_packet *packet)
{
return packet->size == packet->overhead;
}
/* This represents a remote transport address.
* For local transport addresses, we just use union sctp_addr.
*
* RFC2960 Section 1.4 Key Terms
*
* o Transport address: A Transport Address is traditionally defined
* by Network Layer address, Transport Layer protocol and Transport
* Layer port number. In the case of SCTP running over IP, a
* transport address is defined by the combination of an IP address
* and an SCTP port number (where SCTP is the Transport protocol).
*
* RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
*
* o The sender keeps a separate congestion control parameter set for
* each of the destination addresses it can send to (not each
* source-destination pair but for each destination). The parameters
* should decay if the address is not used for a long enough time
* period.
*
*/
struct sctp_transport {
/* A list of transports. */
struct list_head transports;
struct rhlist_head node;
/* Reference counting. */
refcount_t refcnt;
/* RTO-Pending : A flag used to track if one of the DATA
* chunks sent to this address is currently being
* used to compute a RTT. If this flag is 0,
* the next DATA chunk sent to this destination
* should be used to compute a RTT and this flag
* should be set. Every time the RTT
* calculation completes (i.e. the DATA chunk
* is SACK'd) clear this flag.
*/
__u32 rto_pending:1,
/*
* hb_sent : a flag that signals that we have a pending
* heartbeat.
*/
hb_sent:1,
/* Is the Path MTU update pending on this tranport */
pmtu_pending:1,
dst_pending_confirm:1, /* need to confirm neighbour */
/* Has this transport moved the ctsn since we last sacked */
sack_generation:1;
u32 dst_cookie;
struct flowi fl;
/* This is the peer's IP address and port. */
union sctp_addr ipaddr;
/* These are the functions we call to handle LLP stuff. */
struct sctp_af *af_specific;
/* Which association do we belong to? */
struct sctp_association *asoc;
/* RFC2960
*
* 12.3 Per Transport Address Data
*
* For each destination transport address in the peer's
* address list derived from the INIT or INIT ACK chunk, a
* number of data elements needs to be maintained including:
*/
/* RTO : The current retransmission timeout value. */
unsigned long rto;
__u32 rtt; /* This is the most recent RTT. */
/* RTTVAR : The current RTT variation. */
__u32 rttvar;
/* SRTT : The current smoothed round trip time. */
__u32 srtt;
/*
* These are the congestion stats.
*/
/* cwnd : The current congestion window. */
__u32 cwnd; /* This is the actual cwnd. */
/* ssthresh : The current slow start threshold value. */
__u32 ssthresh;
/* partial : The tracking method for increase of cwnd when in
* bytes acked : congestion avoidance mode (see Section 6.2.2)
*/
__u32 partial_bytes_acked;
/* Data that has been sent, but not acknowledged. */
__u32 flight_size;
__u32 burst_limited; /* Holds old cwnd when max.burst is applied */
/* Destination */
struct dst_entry *dst;
/* Source address. */
union sctp_addr saddr;
/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
* the destination address every heartbeat interval.
*/
unsigned long hbinterval;
/* SACK delay timeout */
unsigned long sackdelay;
__u32 sackfreq;
atomic_t mtu_info;
/* When was the last time that we heard from this transport? We use
* this to pick new active and retran paths.
*/
ktime_t last_time_heard;
/* When was the last time that we sent a chunk using this
* transport? We use this to check for idle transports
*/
unsigned long last_time_sent;
/* Last time(in jiffies) when cwnd is reduced due to the congestion
* indication based on ECNE chunk.
*/
unsigned long last_time_ecne_reduced;
__be16 encap_port;
/* This is the max_retrans value for the transport and will
* be initialized from the assocs value. This can be changed
* using the SCTP_SET_PEER_ADDR_PARAMS socket option.
*/
__u16 pathmaxrxt;
__u32 flowlabel;
__u8 dscp;
/* This is the partially failed retrans value for the transport
* and will be initialized from the assocs value. This can be changed
* using the SCTP_PEER_ADDR_THLDS socket option
*/
__u16 pf_retrans;
/* Used for primary path switchover. */
__u16 ps_retrans;
/* PMTU : The current known path MTU. */
__u32 pathmtu;
/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
__u32 param_flags;
/* The number of times INIT has been sent on this transport. */
int init_sent_count;
/* state : The current state of this destination,
* : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
*/
int state;
/* These are the error stats for this destination. */
/* Error count : The current error count for this destination. */
unsigned short error_count;
/* Per : A timer used by each destination.
* Destination :
* Timer :
*
* [Everywhere else in the text this is called T3-rtx. -ed]
*/
struct timer_list T3_rtx_timer;
/* Heartbeat timer is per destination. */
struct timer_list hb_timer;
/* Timer to handle ICMP proto unreachable envets */
struct timer_list proto_unreach_timer;
/* Timer to handler reconf chunk rtx */
struct timer_list reconf_timer;
/* Since we're using per-destination retransmission timers
* (see above), we're also using per-destination "transmitted"
* queues. This probably ought to be a private struct
* accessible only within the outqueue, but it's not, yet.
*/
struct list_head transmitted;
/* We build bundle-able packets for this transport here. */
struct sctp_packet packet;
/* This is the list of transports that have chunks to send. */
struct list_head send_ready;
/* State information saved for SFR_CACC algorithm. The key
* idea in SFR_CACC is to maintain state at the sender on a
* per-destination basis when a changeover happens.
* char changeover_active;
* char cycling_changeover;
* __u32 next_tsn_at_change;
* char cacc_saw_newack;
*/
struct {
/* An unsigned integer, which stores the next TSN to be
* used by the sender, at the moment of changeover.
*/
__u32 next_tsn_at_change;
/* A flag which indicates the occurrence of a changeover */
char changeover_active;
/* A flag which indicates whether the change of primary is
* the first switch to this destination address during an
* active switch.
*/
char cycling_changeover;
/* A temporary flag, which is used during the processing of
* a SACK to estimate the causative TSN(s)'s group.
*/
char cacc_saw_newack;
} cacc;
/* 64-bit random number sent with heartbeat. */
__u64 hb_nonce;
struct rcu_head rcu;
};
struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
gfp_t);
void sctp_transport_set_owner(struct sctp_transport *,
struct sctp_association *);
void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
struct sctp_sock *);
void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
void sctp_transport_free(struct sctp_transport *);
void sctp_transport_reset_t3_rtx(struct sctp_transport *);
void sctp_transport_reset_hb_timer(struct sctp_transport *);
void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
int sctp_transport_hold(struct sctp_transport *);
void sctp_transport_put(struct sctp_transport *);
void sctp_transport_update_rto(struct sctp_transport *, __u32);
void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
void sctp_transport_lower_cwnd(struct sctp_transport *t,
enum sctp_lower_cwnd reason);
void sctp_transport_burst_limited(struct sctp_transport *);
void sctp_transport_burst_reset(struct sctp_transport *);
unsigned long sctp_transport_timeout(struct sctp_transport *);
void sctp_transport_reset(struct sctp_transport *t);
bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
void sctp_transport_immediate_rtx(struct sctp_transport *);
void sctp_transport_dst_release(struct sctp_transport *t);
void sctp_transport_dst_confirm(struct sctp_transport *t);
/* This is the structure we use to queue packets as they come into
* SCTP. We write packets to it and read chunks from it.
*/
struct sctp_inq {
/* This is actually a queue of sctp_chunk each
* containing a partially decoded packet.
*/
struct list_head in_chunk_list;
/* This is the packet which is currently off the in queue and is
* being worked on through the inbound chunk processing.
*/
struct sctp_chunk *in_progress;
/* This is the delayed task to finish delivering inbound
* messages.
*/
struct work_struct immediate;
};
void sctp_inq_init(struct sctp_inq *);
void sctp_inq_free(struct sctp_inq *);
void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
/* This is the structure we use to hold outbound chunks. You push
* chunks in and they automatically pop out the other end as bundled
* packets (it calls (*output_handler)()).
*
* This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
* and 8.2 of the v13 draft.
*
* It handles retransmissions. The connection to the timeout portion
* of the state machine is through sctp_..._timeout() and timeout_handler.
*
* If you feed it SACKs, it will eat them.
*
* If you give it big chunks, it will fragment them.
*
* It assigns TSN's to data chunks. This happens at the last possible
* instant before transmission.
*
* When free()'d, it empties itself out via output_handler().
*/
struct sctp_outq {
struct sctp_association *asoc;
/* Data pending that has never been transmitted. */
struct list_head out_chunk_list;
/* Stream scheduler being used */
struct sctp_sched_ops *sched;
unsigned int out_qlen; /* Total length of queued data chunks. */
/* Error of send failed, may used in SCTP_SEND_FAILED event. */
unsigned int error;
/* These are control chunks we want to send. */
struct list_head control_chunk_list;
/* These are chunks that have been sacked but are above the
* CTSN, or cumulative tsn ack point.
*/
struct list_head sacked;
/* Put chunks on this list to schedule them for
* retransmission.
*/
struct list_head retransmit;
/* Put chunks on this list to save them for FWD TSN processing as
* they were abandoned.
*/
struct list_head abandoned;
/* How many unackd bytes do we have in-flight? */
__u32 outstanding_bytes;
/* Are we doing fast-rtx on this queue */
char fast_rtx;
/* Corked? */
char cork;
};
void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
void sctp_outq_teardown(struct sctp_outq *);
void sctp_outq_free(struct sctp_outq*);
void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
int sctp_outq_is_empty(const struct sctp_outq *);
void sctp_outq_restart(struct sctp_outq *);
void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
enum sctp_retransmit_reason reason);
void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
void sctp_prsctp_prune(struct sctp_association *asoc,
struct sctp_sndrcvinfo *sinfo, int msg_len);
void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
/* Uncork and flush an outqueue. */
static inline void sctp_outq_cork(struct sctp_outq *q)
{
q->cork = 1;
}
/* SCTP skb control block.
* sctp_input_cb is currently used on rx and sock rx queue
*/
struct sctp_input_cb {
union {
struct inet_skb_parm h4;
#if IS_ENABLED(CONFIG_IPV6)
struct inet6_skb_parm h6;
#endif
} header;
struct sctp_chunk *chunk;
struct sctp_af *af;
__be16 encap_port;
};
#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
struct sctp_output_cb {
struct sk_buff *last;
};
#define SCTP_OUTPUT_CB(__skb) ((struct sctp_output_cb *)&((__skb)->cb[0]))
static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
{
const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
return chunk->head_skb ? : skb;
}
/* These bind address data fields common between endpoints and associations */
struct sctp_bind_addr {
/* RFC 2960 12.1 Parameters necessary for the SCTP instance
*
* SCTP Port: The local SCTP port number the endpoint is
* bound to.
*/
__u16 port;
/* RFC 2960 12.1 Parameters necessary for the SCTP instance
*
* Address List: The list of IP addresses that this instance
* has bound. This information is passed to one's
* peer(s) in INIT and INIT ACK chunks.
*/
struct list_head address_list;
};
void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
void sctp_bind_addr_free(struct sctp_bind_addr *);
int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
const struct sctp_bind_addr *src,
enum sctp_scope scope, gfp_t gfp,
int flags);
int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
const struct sctp_bind_addr *src,
gfp_t gfp);
int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
int new_size, __u8 addr_state, gfp_t gfp);
int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
struct sctp_sock *);
int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
struct sctp_sock *, struct sctp_sock *);
int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
const union sctp_addr *addr);
int sctp_bind_addrs_check(struct sctp_sock *sp,
struct sctp_sock *sp2, int cnt2);
union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr *bp,
const union sctp_addr *addrs,
int addrcnt,
struct sctp_sock *opt);
union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
int *addrs_len,
gfp_t gfp);
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
__u16 port, gfp_t gfp);
enum sctp_scope sctp_scope(const union sctp_addr *addr);
int sctp_in_scope(struct net *net, const union sctp_addr *addr,
const enum sctp_scope scope);
int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
int sctp_is_ep_boundall(struct sock *sk);
/* What type of endpoint? */
enum sctp_endpoint_type {
SCTP_EP_TYPE_SOCKET,
SCTP_EP_TYPE_ASSOCIATION,
};
/*
* A common base class to bridge the implmentation view of a
* socket (usually listening) endpoint versus an association's
* local endpoint.
* This common structure is useful for several purposes:
* 1) Common interface for lookup routines.
* a) Subfunctions work for either endpoint or association
* b) Single interface to lookup allows hiding the lookup lock rather
* than acquiring it externally.
* 2) Common interface for the inbound chunk handling/state machine.
* 3) Common object handling routines for reference counting, etc.
* 4) Disentangle association lookup from endpoint lookup, where we
* do not have to find our endpoint to find our association.
*
*/
struct sctp_ep_common {
/* Fields to help us manage our entries in the hash tables. */
struct hlist_node node;
int hashent;
/* Runtime type information. What kind of endpoint is this? */
enum sctp_endpoint_type type;
/* Some fields to help us manage this object.
* refcnt - Reference count access to this object.
* dead - Do not attempt to use this object.
*/
refcount_t refcnt;
bool dead;
/* What socket does this endpoint belong to? */
struct sock *sk;
/* Cache netns and it won't change once set */
struct net *net;
/* This is where we receive inbound chunks. */
struct sctp_inq inqueue;
/* This substructure includes the defining parameters of the
* endpoint:
* bind_addr.port is our shared port number.
* bind_addr.address_list is our set of local IP addresses.
*/
struct sctp_bind_addr bind_addr;
};
/* RFC Section 1.4 Key Terms
*
* o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
* multi-homed host, an SCTP endpoint is represented to its peers as a
* combination of a set of eligible destination transport addresses to
* which SCTP packets can be sent and a set of eligible source
* transport addresses from which SCTP packets can be received.
* All transport addresses used by an SCTP endpoint must use the
* same port number, but can use multiple IP addresses. A transport
* address used by an SCTP endpoint must not be used by another
* SCTP endpoint. In other words, a transport address is unique
* to an SCTP endpoint.
*
* From an implementation perspective, each socket has one of these.
* A TCP-style socket will have exactly one association on one of
* these. An UDP-style socket will have multiple associations hanging
* off one of these.
*/
struct sctp_endpoint {
/* Common substructure for endpoint and association. */
struct sctp_ep_common base;
/* Associations: A list of current associations and mappings
* to the data consumers for each association. This
* may be in the form of a hash table or other
* implementation dependent structure. The data
* consumers may be process identification
* information such as file descriptors, named pipe
* pointer, or table pointers dependent on how SCTP
* is implemented.
*/
/* This is really a list of struct sctp_association entries. */
struct list_head asocs;
/* Secret Key: A secret key used by this endpoint to compute
* the MAC. This SHOULD be a cryptographic quality
* random number with a sufficient length.
* Discussion in [RFC1750] can be helpful in
* selection of the key.
*/
__u8 secret_key[SCTP_SECRET_SIZE];
/* digest: This is a digest of the sctp cookie. This field is
* only used on the receive path when we try to validate
* that the cookie has not been tampered with. We put
* this here so we pre-allocate this once and can re-use
* on every receive.
*/
__u8 *digest;
/* sendbuf acct. policy. */
__u32 sndbuf_policy;
/* rcvbuf acct. policy. */
__u32 rcvbuf_policy;
/* SCTP AUTH: array of the HMACs that will be allocated
* we need this per association so that we don't serialize
*/
struct crypto_shash **auth_hmacs;
/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
struct sctp_hmac_algo_param *auth_hmacs_list;
/* SCTP-AUTH: chunks to authenticate encoded into parameter */
struct sctp_chunks_param *auth_chunk_list;
/* SCTP-AUTH: endpoint shared keys */
struct list_head endpoint_shared_keys;
__u16 active_key_id;
__u8 ecn_enable:1,
auth_enable:1,
intl_enable:1,
prsctp_enable:1,
asconf_enable:1,
reconf_enable:1;
__u8 strreset_enable;
/* Security identifiers from incoming (INIT). These are set by
* security_sctp_assoc_request(). These will only be used by
* SCTP TCP type sockets and peeled off connections as they
* cause a new socket to be generated. security_sctp_sk_clone()
* will then plug these into the new socket.
*/
u32 secid;
u32 peer_secid;
};
/* Recover the outter endpoint structure. */
static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
{
struct sctp_endpoint *ep;
ep = container_of(base, struct sctp_endpoint, base);
return ep;
}
/* These are function signatures for manipulating endpoints. */
struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
void sctp_endpoint_free(struct sctp_endpoint *);
void sctp_endpoint_put(struct sctp_endpoint *);
void sctp_endpoint_hold(struct sctp_endpoint *);
void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
struct sctp_association *sctp_endpoint_lookup_assoc(
const struct sctp_endpoint *ep,
const union sctp_addr *paddr,
struct sctp_transport **);
bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
const union sctp_addr *paddr);
struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
struct net *, const union sctp_addr *);
bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
const union sctp_addr *paddr);
int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
enum sctp_cid cid, struct sctp_init_chunk *peer_init,
struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
const union sctp_addr *peer,
struct sctp_init_chunk *init, gfp_t gfp);
__u32 sctp_generate_tag(const struct sctp_endpoint *);
__u32 sctp_generate_tsn(const struct sctp_endpoint *);
struct sctp_inithdr_host {
__u32 init_tag;
__u32 a_rwnd;
__u16 num_outbound_streams;
__u16 num_inbound_streams;
__u32 initial_tsn;
};
struct sctp_stream_priorities {
/* List of priorities scheduled */
struct list_head prio_sched;
/* List of streams scheduled */
struct list_head active;
/* The next stream in line */
struct sctp_stream_out_ext *next;
__u16 prio;
};
struct sctp_stream_out_ext {
__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
struct list_head outq; /* chunks enqueued by this stream */
union {
struct {
/* Scheduled streams list */
struct list_head prio_list;
struct sctp_stream_priorities *prio_head;
};
/* Fields used by RR scheduler */
struct {
struct list_head rr_list;
};
};
};
struct sctp_stream_out {
union {
__u32 mid;
__u16 ssn;
};
__u32 mid_uo;
struct sctp_stream_out_ext *ext;
__u8 state;
};
struct sctp_stream_in {
union {
__u32 mid;
__u16 ssn;
};
__u32 mid_uo;
__u32 fsn;
__u32 fsn_uo;
char pd_mode;
char pd_mode_uo;
};
struct sctp_stream {
GENRADIX(struct sctp_stream_out) out;
GENRADIX(struct sctp_stream_in) in;
__u16 outcnt;
__u16 incnt;
/* Current stream being sent, if any */
struct sctp_stream_out *out_curr;
union {
/* Fields used by priority scheduler */
struct {
/* List of priorities scheduled */
struct list_head prio_list;
};
/* Fields used by RR scheduler */
struct {
/* List of streams scheduled */
struct list_head rr_list;
/* The next stream in line */
struct sctp_stream_out_ext *rr_next;
};
};
struct sctp_stream_interleave *si;
};
static inline struct sctp_stream_out *sctp_stream_out(
struct sctp_stream *stream,
__u16 sid)
{
return genradix_ptr(&stream->out, sid);
}
static inline struct sctp_stream_in *sctp_stream_in(
struct sctp_stream *stream,
__u16 sid)
{
return genradix_ptr(&stream->in, sid);
}
#define SCTP_SO(s, i) sctp_stream_out((s), (i))
#define SCTP_SI(s, i) sctp_stream_in((s), (i))
#define SCTP_STREAM_CLOSED 0x00
#define SCTP_STREAM_OPEN 0x01
static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
{
return stream->si->data_chunk_len;
}
static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
{
return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
}
static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
{
return stream->si->ftsn_chunk_len;
}
static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
{
return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
}
/* SCTP_GET_ASSOC_STATS counters */
struct sctp_priv_assoc_stats {
/* Maximum observed rto in the association during subsequent
* observations. Value is set to 0 if no RTO measurement took place
* The transport where the max_rto was observed is returned in
* obs_rto_ipaddr
*/
struct sockaddr_storage obs_rto_ipaddr;
__u64 max_obs_rto;
/* Total In and Out SACKs received and sent */
__u64 isacks;
__u64 osacks;
/* Total In and Out packets received and sent */
__u64 opackets;
__u64 ipackets;
/* Total retransmitted chunks */
__u64 rtxchunks;
/* TSN received > next expected */
__u64 outofseqtsns;
/* Duplicate Chunks received */
__u64 idupchunks;
/* Gap Ack Blocks received */
__u64 gapcnt;
/* Unordered data chunks sent and received */
__u64 ouodchunks;
__u64 iuodchunks;
/* Ordered data chunks sent and received */
__u64 oodchunks;
__u64 iodchunks;
/* Control chunks sent and received */
__u64 octrlchunks;
__u64 ictrlchunks;
};
/* RFC2960
*
* 12. Recommended Transmission Control Block (TCB) Parameters
*
* This section details a recommended set of parameters that should
* be contained within the TCB for an implementation. This section is
* for illustrative purposes and should not be deemed as requirements
* on an implementation or as an exhaustive list of all parameters
* inside an SCTP TCB. Each implementation may need its own additional
* parameters for optimization.
*/
/* Here we have information about each individual association. */
struct sctp_association {
/* A base structure common to endpoint and association.
* In this context, it represents the associations's view
* of the local endpoint of the association.
*/
struct sctp_ep_common base;
/* Associations on the same socket. */
struct list_head asocs;
/* association id. */
sctp_assoc_t assoc_id;
/* This is our parent endpoint. */
struct sctp_endpoint *ep;
/* These are those association elements needed in the cookie. */
struct sctp_cookie c;
/* This is all information about our peer. */
struct {
/* transport_addr_list
*
* Peer : A list of SCTP transport addresses that the
* Transport : peer is bound to. This information is derived
* Address : from the INIT or INIT ACK and is used to
* List : associate an inbound packet with a given
* : association. Normally this information is
* : hashed or keyed for quick lookup and access
* : of the TCB.
* : The list is also initialized with the list
* : of addresses passed with the sctp_connectx()
* : call.
*
* It is a list of SCTP_transport's.
*/
struct list_head transport_addr_list;
/* rwnd
*
* Peer Rwnd : Current calculated value of the peer's rwnd.
*/
__u32 rwnd;
/* transport_count
*
* Peer : A count of the number of peer addresses
* Transport : in the Peer Transport Address List.
* Address :
* Count :
*/
__u16 transport_count;
/* port
* The transport layer port number.
*/
__u16 port;
/* primary_path
*
* Primary : This is the current primary destination
* Path : transport address of the peer endpoint. It
* : may also specify a source transport address
* : on this endpoint.
*
* All of these paths live on transport_addr_list.
*
* At the bakeoffs, we discovered that the intent of
* primaryPath is that it only changes when the ULP
* asks to have it changed. We add the activePath to
* designate the connection we are currently using to
* transmit new data and most control chunks.
*/
struct sctp_transport *primary_path;
/* Cache the primary path address here, when we
* need a an address for msg_name.
*/
union sctp_addr primary_addr;
/* active_path
* The path that we are currently using to
* transmit new data and most control chunks.
*/
struct sctp_transport *active_path;
/* retran_path
*
* RFC2960 6.4 Multi-homed SCTP Endpoints
* ...
* Furthermore, when its peer is multi-homed, an
* endpoint SHOULD try to retransmit a chunk to an
* active destination transport address that is
* different from the last destination address to
* which the DATA chunk was sent.
*/
struct sctp_transport *retran_path;
/* Pointer to last transport I have sent on. */
struct sctp_transport *last_sent_to;
/* This is the last transport I have received DATA on. */
struct sctp_transport *last_data_from;
/*
* Mapping An array of bits or bytes indicating which out of
* Array order TSN's have been received (relative to the
* Last Rcvd TSN). If no gaps exist, i.e. no out of
* order packets have been received, this array
* will be set to all zero. This structure may be
* in the form of a circular buffer or bit array.
*
* Last Rcvd : This is the last TSN received in
* TSN : sequence. This value is set initially by
* : taking the peer's Initial TSN, received in
* : the INIT or INIT ACK chunk, and subtracting
* : one from it.
*
* Throughout most of the specification this is called the
* "Cumulative TSN ACK Point". In this case, we
* ignore the advice in 12.2 in favour of the term
* used in the bulk of the text. This value is hidden
* in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
*/
struct sctp_tsnmap tsn_map;
/* This mask is used to disable sending the ASCONF chunk
* with specified parameter to peer.
*/
__be16 addip_disabled_mask;
/* These are capabilities which our peer advertised. */
__u16 ecn_capable:1, /* Can peer do ECN? */
ipv4_address:1, /* Peer understands IPv4 addresses? */
ipv6_address:1, /* Peer understands IPv6 addresses? */
hostname_address:1, /* Peer understands DNS addresses? */
asconf_capable:1, /* Does peer support ADDIP? */
prsctp_capable:1, /* Can peer do PR-SCTP? */
reconf_capable:1, /* Can peer do RE-CONFIG? */
intl_capable:1, /* Can peer do INTERLEAVE */
auth_capable:1, /* Is peer doing SCTP-AUTH? */
/* sack_needed:
* This flag indicates if the next received
* packet is to be responded to with a
* SACK. This is initialized to 0. When a packet
* is received sack_cnt is incremented. If this value
* reaches 2 or more, a SACK is sent and the
* value is reset to 0. Note: This is used only
* when no DATA chunks are received out of
* order. When DATA chunks are out of order,
* SACK's are not delayed (see Section 6).
*/
sack_needed:1, /* Do we need to sack the peer? */
sack_generation:1,
zero_window_announced:1;
__u32 sack_cnt;
__u32 adaptation_ind; /* Adaptation Code point. */
struct sctp_inithdr_host i;
void *cookie;
int cookie_len;
/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
* C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
* Initial TSN Value minus 1
*/
__u32 addip_serial;
/* SCTP-AUTH: We need to know pears random number, hmac list
* and authenticated chunk list. All that is part of the
* cookie and these are just pointers to those locations
*/
struct sctp_random_param *peer_random;
struct sctp_chunks_param *peer_chunks;
struct sctp_hmac_algo_param *peer_hmacs;
} peer;
/* State : A state variable indicating what state the
* : association is in, i.e. COOKIE-WAIT,
* : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
* : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
*
* Note: No "CLOSED" state is illustrated since if a
* association is "CLOSED" its TCB SHOULD be removed.
*
* In this implementation we DO have a CLOSED
* state which is used during initiation and shutdown.
*
* State takes values from SCTP_STATE_*.
*/
enum sctp_state state;
/* Overall : The overall association error count.
* Error Count : [Clear this any time I get something.]
*/
int overall_error_count;
/* The cookie life I award for any cookie. */
ktime_t cookie_life;
/* These are the association's initial, max, and min RTO values.
* These values will be initialized by system defaults, but can
* be modified via the SCTP_RTOINFO socket option.
*/
unsigned long rto_initial;
unsigned long rto_max;
unsigned long rto_min;
/* Maximum number of new data packets that can be sent in a burst. */
int max_burst;
/* This is the max_retrans value for the association. This value will
* be initialized from system defaults, but can be
* modified by the SCTP_ASSOCINFO socket option.
*/
int max_retrans;
/* This is the partially failed retrans value for the transport
* and will be initialized from the assocs value. This can be
* changed using the SCTP_PEER_ADDR_THLDS socket option
*/
__u16 pf_retrans;
/* Used for primary path switchover. */
__u16 ps_retrans;
/* Maximum number of times the endpoint will retransmit INIT */
__u16 max_init_attempts;
/* How many times have we resent an INIT? */
__u16 init_retries;
/* The largest timeout or RTO value to use in attempting an INIT */
unsigned long max_init_timeo;
/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
* the destination address every heartbeat interval. This value
* will be inherited by all new transports.
*/
unsigned long hbinterval;
__be16 encap_port;
/* This is the max_retrans value for new transports in the
* association.
*/
__u16 pathmaxrxt;
__u32 flowlabel;
__u8 dscp;
/* Flag that path mtu update is pending */
__u8 pmtu_pending;
/* Association : The smallest PMTU discovered for all of the
* PMTU : peer's transport addresses.
*/
__u32 pathmtu;
/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
__u32 param_flags;
__u32 sackfreq;
/* SACK delay timeout */
unsigned long sackdelay;
unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
/* Transport to which SHUTDOWN chunk was last sent. */
struct sctp_transport *shutdown_last_sent_to;
/* Transport to which INIT chunk was last sent. */
struct sctp_transport *init_last_sent_to;
/* How many times have we resent a SHUTDOWN */
int shutdown_retries;
/* Next TSN : The next TSN number to be assigned to a new
* : DATA chunk. This is sent in the INIT or INIT
* : ACK chunk to the peer and incremented each
* : time a DATA chunk is assigned a TSN
* : (normally just prior to transmit or during
* : fragmentation).
*/
__u32 next_tsn;
/*
* Last Rcvd : This is the last TSN received in sequence. This value
* TSN : is set initially by taking the peer's Initial TSN,
* : received in the INIT or INIT ACK chunk, and
* : subtracting one from it.
*
* Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
*/
__u32 ctsn_ack_point;
/* PR-SCTP Advanced.Peer.Ack.Point */
__u32 adv_peer_ack_point;
/* Highest TSN that is acknowledged by incoming SACKs. */
__u32 highest_sacked;
/* TSN marking the fast recovery exit point */
__u32 fast_recovery_exit;
/* Flag to track the current fast recovery state */
__u8 fast_recovery;
/* The number of unacknowledged data chunks. Reported through
* the SCTP_STATUS sockopt.
*/
__u16 unack_data;
/* The total number of data chunks that we've had to retransmit
* as the result of a T3 timer expiration
*/
__u32 rtx_data_chunks;
/* This is the association's receive buffer space. This value is used
* to set a_rwnd field in an INIT or a SACK chunk.
*/
__u32 rwnd;
/* This is the last advertised value of rwnd over a SACK chunk. */
__u32 a_rwnd;
/* Number of bytes by which the rwnd has slopped. The rwnd is allowed
* to slop over a maximum of the association's frag_point.
*/
__u32 rwnd_over;
/* Keeps treack of rwnd pressure. This happens when we have
* a window, but not recevie buffer (i.e small packets). This one
* is releases slowly (1 PMTU at a time ).
*/
__u32 rwnd_press;
/* This is the sndbuf size in use for the association.
* This corresponds to the sndbuf size for the association,
* as specified in the sk->sndbuf.
*/
int sndbuf_used;
/* This is the amount of memory that this association has allocated
* in the receive path at any given time.
*/
atomic_t rmem_alloc;
/* This is the wait queue head for send requests waiting on
* the association sndbuf space.
*/
wait_queue_head_t wait;
/* The message size at which SCTP fragmentation will occur. */
__u32 frag_point;
__u32 user_frag;
/* Counter used to count INIT errors. */
int init_err_counter;
/* Count the number of INIT cycles (for doubling timeout). */
int init_cycle;
/* Default send parameters. */
__u16 default_stream;
__u16 default_flags;
__u32 default_ppid;
__u32 default_context;
__u32 default_timetolive;
/* Default receive parameters */
__u32 default_rcv_context;
/* Stream arrays */
struct sctp_stream stream;
/* All outbound chunks go through this structure. */
struct sctp_outq outqueue;
/* A smart pipe that will handle reordering and fragmentation,
* as well as handle passing events up to the ULP.
*/
struct sctp_ulpq ulpq;
/* Last TSN that caused an ECNE Chunk to be sent. */
__u32 last_ecne_tsn;
/* Last TSN that caused a CWR Chunk to be sent. */
__u32 last_cwr_tsn;
/* How many duplicated TSNs have we seen? */
int numduptsns;
/* These are to support
* "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
* and Enforcement of Flow and Message Limits"
* <draft-ietf-tsvwg-addip-sctp-02.txt>
* or "ADDIP" for short.
*/
/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
*
* R1) One and only one ASCONF Chunk MAY be in transit and
* unacknowledged at any one time. If a sender, after sending
* an ASCONF chunk, decides it needs to transfer another
* ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
* returns from the previous ASCONF Chunk before sending a
* subsequent ASCONF. Note this restriction binds each side,
* so at any time two ASCONF may be in-transit on any given
* association (one sent from each endpoint).
*
* [This is our one-and-only-one ASCONF in flight. If we do
* not have an ASCONF in flight, this is NULL.]
*/
struct sctp_chunk *addip_last_asconf;
/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
*
* This is needed to implement itmes E1 - E4 of the updated
* spec. Here is the justification:
*
* Since the peer may bundle multiple ASCONF chunks toward us,
* we now need the ability to cache multiple ACKs. The section
* describes in detail how they are cached and cleaned up.
*/
struct list_head asconf_ack_list;
/* These ASCONF chunks are waiting to be sent.
*
* These chunaks can't be pushed to outqueue until receiving
* ASCONF_ACK for the previous ASCONF indicated by
* addip_last_asconf, so as to guarantee that only one ASCONF
* is in flight at any time.
*
* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
*
* In defining the ASCONF Chunk transfer procedures, it is
* essential that these transfers MUST NOT cause congestion
* within the network. To achieve this, we place these
* restrictions on the transfer of ASCONF Chunks:
*
* R1) One and only one ASCONF Chunk MAY be in transit and
* unacknowledged at any one time. If a sender, after sending
* an ASCONF chunk, decides it needs to transfer another
* ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
* returns from the previous ASCONF Chunk before sending a
* subsequent ASCONF. Note this restriction binds each side,
* so at any time two ASCONF may be in-transit on any given
* association (one sent from each endpoint).
*
*
* [I really think this is EXACTLY the sort of intelligence
* which already resides in sctp_outq. Please move this
* queue and its supporting logic down there. --piggy]
*/
struct list_head addip_chunk_list;
/* ADDIP Section 4.1 ASCONF Chunk Procedures
*
* A2) A serial number should be assigned to the Chunk. The
* serial number SHOULD be a monotonically increasing
* number. The serial number SHOULD be initialized at
* the start of the association to the same value as the
* Initial TSN and every time a new ASCONF chunk is created
* it is incremented by one after assigning the serial number
* to the newly created chunk.
*
* ADDIP
* 3.1.1 Address/Stream Configuration Change Chunk (ASCONF)
*
* Serial Number : 32 bits (unsigned integer)
*
* This value represents a Serial Number for the ASCONF
* Chunk. The valid range of Serial Number is from 0 to
* 4294967295 (2^32 - 1). Serial Numbers wrap back to 0
* after reaching 4294967295.
*/
__u32 addip_serial;
int src_out_of_asoc_ok;
union sctp_addr *asconf_addr_del_pending;
struct sctp_transport *new_transport;
/* SCTP AUTH: list of the endpoint shared keys. These
* keys are provided out of band by the user applicaton
* and can't change during the lifetime of the association
*/
struct list_head endpoint_shared_keys;
/* SCTP AUTH:
* The current generated assocaition shared key (secret)
*/
struct sctp_auth_bytes *asoc_shared_key;
struct sctp_shared_key *shkey;
/* SCTP AUTH: hmac id of the first peer requested algorithm
* that we support.
*/
__u16 default_hmac_id;
__u16 active_key_id;
__u8 need_ecne:1, /* Need to send an ECNE Chunk? */
temp:1, /* Is it a temporary association? */
pf_expose:2, /* Expose pf state? */
force_delay:1;
__u8 strreset_enable;
__u8 strreset_outstanding; /* request param count on the fly */
__u32 strreset_outseq; /* Update after receiving response */
__u32 strreset_inseq; /* Update after receiving request */
__u32 strreset_result[2]; /* save the results of last 2 responses */
struct sctp_chunk *strreset_chunk; /* save request chunk */
struct sctp_priv_assoc_stats stats;
int sent_cnt_removable;
__u16 subscribe;
__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
struct rcu_head rcu;
};
/* An eyecatcher for determining if we are really looking at an
* association data structure.
*/
enum {
SCTP_ASSOC_EYECATCHER = 0xa550c123,
};
/* Recover the outter association structure. */
static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
{
struct sctp_association *asoc;
asoc = container_of(base, struct sctp_association, base);
return asoc;
}
/* These are function signatures for manipulating associations. */
struct sctp_association *
sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
enum sctp_scope scope, gfp_t gfp);
void sctp_association_free(struct sctp_association *);
void sctp_association_put(struct sctp_association *);
void sctp_association_hold(struct sctp_association *);
struct sctp_transport *sctp_assoc_choose_alter_transport(
struct sctp_association *, struct sctp_transport *);
void sctp_assoc_update_retran_path(struct sctp_association *);
struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
const union sctp_addr *);
int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
const union sctp_addr *laddr);
struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
const union sctp_addr *address,
const gfp_t gfp,
const int peer_state);
void sctp_assoc_del_peer(struct sctp_association *asoc,
const union sctp_addr *addr);
void sctp_assoc_rm_peer(struct sctp_association *asoc,
struct sctp_transport *peer);
void sctp_assoc_control_transport(struct sctp_association *asoc,
struct sctp_transport *transport,
enum sctp_transport_cmd command,
sctp_sn_error_t error);
struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
void sctp_assoc_migrate(struct sctp_association *, struct sock *);
int sctp_assoc_update(struct sctp_association *old,
struct sctp_association *new);
__u32 sctp_association_get_next_tsn(struct sctp_association *);
void sctp_assoc_update_frag_point(struct sctp_association *asoc);
void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
void sctp_assoc_set_primary(struct sctp_association *,
struct sctp_transport *);
void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
struct sctp_transport *);
int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
enum sctp_scope scope, gfp_t gfp);
int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
struct sctp_cookie*,
gfp_t gfp);
int sctp_assoc_set_id(struct sctp_association *, gfp_t);
void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
const struct sctp_association *asoc,
__be32 serial);
void sctp_asconf_queue_teardown(struct sctp_association *asoc);
int sctp_cmp_addr_exact(const union sctp_addr *ss1,
const union sctp_addr *ss2);
struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
/* A convenience structure to parse out SCTP specific CMSGs. */
struct sctp_cmsgs {
struct sctp_initmsg *init;
struct sctp_sndrcvinfo *srinfo;
struct sctp_sndinfo *sinfo;
struct sctp_prinfo *prinfo;
struct sctp_authinfo *authinfo;
struct msghdr *addrs_msg;
};
/* Structure for tracking memory objects */
struct sctp_dbg_objcnt_entry {
char *label;
atomic_t *counter;
};
#endif /* __sctp_structs_h__ */
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