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tcp.h
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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for the TCP module.
*
* Version: @(#)tcp.h 1.0.5 05/23/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _TCP_H
#define _TCP_H
#define TCP_DEBUG 1
#define FASTRETRANS_DEBUG 1
/* Cancel timers, when they are not required. */
#undef TCP_CLEAR_TIMERS
#include <linux/config.h>
#include <linux/list.h>
#include <linux/tcp.h>
#include <linux/slab.h>
#include <linux/cache.h>
#include <linux/percpu.h>
#include <net/checksum.h>
#include <net/request_sock.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ip.h>
#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
#include <linux/ipv6.h>
#endif
#include <linux/seq_file.h>
/* This is for all connections with a full identity, no wildcards.
* New scheme, half the table is for TIME_WAIT, the other half is
* for the rest. I'll experiment with dynamic table growth later.
*/
struct tcp_ehash_bucket {
rwlock_t lock;
struct hlist_head chain;
} __attribute__((__aligned__(8)));
/* This is for listening sockets, thus all sockets which possess wildcards. */
#define TCP_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
/* There are a few simple rules, which allow for local port reuse by
* an application. In essence:
*
* 1) Sockets bound to different interfaces may share a local port.
* Failing that, goto test 2.
* 2) If all sockets have sk->sk_reuse set, and none of them are in
* TCP_LISTEN state, the port may be shared.
* Failing that, goto test 3.
* 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
* address, and none of them are the same, the port may be
* shared.
* Failing this, the port cannot be shared.
*
* The interesting point, is test #2. This is what an FTP server does
* all day. To optimize this case we use a specific flag bit defined
* below. As we add sockets to a bind bucket list, we perform a
* check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
* As long as all sockets added to a bind bucket pass this test,
* the flag bit will be set.
* The resulting situation is that tcp_v[46]_verify_bind() can just check
* for this flag bit, if it is set and the socket trying to bind has
* sk->sk_reuse set, we don't even have to walk the owners list at all,
* we return that it is ok to bind this socket to the requested local port.
*
* Sounds like a lot of work, but it is worth it. In a more naive
* implementation (ie. current FreeBSD etc.) the entire list of ports
* must be walked for each data port opened by an ftp server. Needless
* to say, this does not scale at all. With a couple thousand FTP
* users logged onto your box, isn't it nice to know that new data
* ports are created in O(1) time? I thought so. ;-) -DaveM
*/
struct tcp_bind_bucket {
unsigned short port;
signed short fastreuse;
struct hlist_node node;
struct hlist_head owners;
};
#define tb_for_each(tb, node, head) hlist_for_each_entry(tb, node, head, node)
struct tcp_bind_hashbucket {
spinlock_t lock;
struct hlist_head chain;
};
static inline struct tcp_bind_bucket *__tb_head(struct tcp_bind_hashbucket *head)
{
return hlist_entry(head->chain.first, struct tcp_bind_bucket, node);
}
static inline struct tcp_bind_bucket *tb_head(struct tcp_bind_hashbucket *head)
{
return hlist_empty(&head->chain) ? NULL : __tb_head(head);
}
extern struct tcp_hashinfo {
/* This is for sockets with full identity only. Sockets here will
* always be without wildcards and will have the following invariant:
*
* TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
*
* First half of the table is for sockets not in TIME_WAIT, second half
* is for TIME_WAIT sockets only.
*/
struct tcp_ehash_bucket *__tcp_ehash;
/* Ok, let's try this, I give up, we do need a local binding
* TCP hash as well as the others for fast bind/connect.
*/
struct tcp_bind_hashbucket *__tcp_bhash;
int __tcp_bhash_size;
int __tcp_ehash_size;
/* All sockets in TCP_LISTEN state will be in here. This is the only
* table where wildcard'd TCP sockets can exist. Hash function here
* is just local port number.
*/
struct hlist_head __tcp_listening_hash[TCP_LHTABLE_SIZE];
/* All the above members are written once at bootup and
* never written again _or_ are predominantly read-access.
*
* Now align to a new cache line as all the following members
* are often dirty.
*/
rwlock_t __tcp_lhash_lock ____cacheline_aligned;
atomic_t __tcp_lhash_users;
wait_queue_head_t __tcp_lhash_wait;
spinlock_t __tcp_portalloc_lock;
} tcp_hashinfo;
#define tcp_ehash (tcp_hashinfo.__tcp_ehash)
#define tcp_bhash (tcp_hashinfo.__tcp_bhash)
#define tcp_ehash_size (tcp_hashinfo.__tcp_ehash_size)
#define tcp_bhash_size (tcp_hashinfo.__tcp_bhash_size)
#define tcp_listening_hash (tcp_hashinfo.__tcp_listening_hash)
#define tcp_lhash_lock (tcp_hashinfo.__tcp_lhash_lock)
#define tcp_lhash_users (tcp_hashinfo.__tcp_lhash_users)
#define tcp_lhash_wait (tcp_hashinfo.__tcp_lhash_wait)
#define tcp_portalloc_lock (tcp_hashinfo.__tcp_portalloc_lock)
extern kmem_cache_t *tcp_bucket_cachep;
extern struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
unsigned short snum);
extern void tcp_bucket_destroy(struct tcp_bind_bucket *tb);
extern void tcp_bucket_unlock(struct sock *sk);
extern int tcp_port_rover;
/* These are AF independent. */
static __inline__ int tcp_bhashfn(__u16 lport)
{
return (lport & (tcp_bhash_size - 1));
}
extern void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
unsigned short snum);
#if (BITS_PER_LONG == 64)
#define TCP_ADDRCMP_ALIGN_BYTES 8
#else
#define TCP_ADDRCMP_ALIGN_BYTES 4
#endif
/* This is a TIME_WAIT bucket. It works around the memory consumption
* problems of sockets in such a state on heavily loaded servers, but
* without violating the protocol specification.
*/
struct tcp_tw_bucket {
/*
* Now struct sock also uses sock_common, so please just
* don't add nothing before this first member (__tw_common) --acme
*/
struct sock_common __tw_common;
#define tw_family __tw_common.skc_family
#define tw_state __tw_common.skc_state
#define tw_reuse __tw_common.skc_reuse
#define tw_bound_dev_if __tw_common.skc_bound_dev_if
#define tw_node __tw_common.skc_node
#define tw_bind_node __tw_common.skc_bind_node
#define tw_refcnt __tw_common.skc_refcnt
volatile unsigned char tw_substate;
unsigned char tw_rcv_wscale;
__u16 tw_sport;
/* Socket demultiplex comparisons on incoming packets. */
/* these five are in inet_sock */
__u32 tw_daddr
__attribute__((aligned(TCP_ADDRCMP_ALIGN_BYTES)));
__u32 tw_rcv_saddr;
__u16 tw_dport;
__u16 tw_num;
/* And these are ours. */
int tw_hashent;
int tw_timeout;
__u32 tw_rcv_nxt;
__u32 tw_snd_nxt;
__u32 tw_rcv_wnd;
__u32 tw_ts_recent;
long tw_ts_recent_stamp;
unsigned long tw_ttd;
struct tcp_bind_bucket *tw_tb;
struct hlist_node tw_death_node;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
struct in6_addr tw_v6_daddr;
struct in6_addr tw_v6_rcv_saddr;
int tw_v6_ipv6only;
#endif
};
static __inline__ void tw_add_node(struct tcp_tw_bucket *tw,
struct hlist_head *list)
{
hlist_add_head(&tw->tw_node, list);
}
static __inline__ void tw_add_bind_node(struct tcp_tw_bucket *tw,
struct hlist_head *list)
{
hlist_add_head(&tw->tw_bind_node, list);
}
static inline int tw_dead_hashed(struct tcp_tw_bucket *tw)
{
return tw->tw_death_node.pprev != NULL;
}
static __inline__ void tw_dead_node_init(struct tcp_tw_bucket *tw)
{
tw->tw_death_node.pprev = NULL;
}
static __inline__ void __tw_del_dead_node(struct tcp_tw_bucket *tw)
{
__hlist_del(&tw->tw_death_node);
tw_dead_node_init(tw);
}
static __inline__ int tw_del_dead_node(struct tcp_tw_bucket *tw)
{
if (tw_dead_hashed(tw)) {
__tw_del_dead_node(tw);
return 1;
}
return 0;
}
#define tw_for_each(tw, node, head) \
hlist_for_each_entry(tw, node, head, tw_node)
#define tw_for_each_inmate(tw, node, jail) \
hlist_for_each_entry(tw, node, jail, tw_death_node)
#define tw_for_each_inmate_safe(tw, node, safe, jail) \
hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
#define tcptw_sk(__sk) ((struct tcp_tw_bucket *)(__sk))
static inline u32 tcp_v4_rcv_saddr(const struct sock *sk)
{
return likely(sk->sk_state != TCP_TIME_WAIT) ?
inet_sk(sk)->rcv_saddr : tcptw_sk(sk)->tw_rcv_saddr;
}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk)
{
return likely(sk->sk_state != TCP_TIME_WAIT) ?
&inet6_sk(sk)->rcv_saddr : &tcptw_sk(sk)->tw_v6_rcv_saddr;
}
static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
{
return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
}
#define tcptw_sk_ipv6only(__sk) (tcptw_sk(__sk)->tw_v6_ipv6only)
static inline int tcp_v6_ipv6only(const struct sock *sk)
{
return likely(sk->sk_state != TCP_TIME_WAIT) ?
ipv6_only_sock(sk) : tcptw_sk_ipv6only(sk);
}
#else
# define __tcp_v6_rcv_saddr(__sk) NULL
# define tcp_v6_rcv_saddr(__sk) NULL
# define tcptw_sk_ipv6only(__sk) 0
# define tcp_v6_ipv6only(__sk) 0
#endif
extern kmem_cache_t *tcp_timewait_cachep;
static inline void tcp_tw_put(struct tcp_tw_bucket *tw)
{
if (atomic_dec_and_test(&tw->tw_refcnt)) {
#ifdef INET_REFCNT_DEBUG
printk(KERN_DEBUG "tw_bucket %p released\n", tw);
#endif
kmem_cache_free(tcp_timewait_cachep, tw);
}
}
extern atomic_t tcp_orphan_count;
extern int tcp_tw_count;
extern void tcp_time_wait(struct sock *sk, int state, int timeo);
extern void tcp_tw_deschedule(struct tcp_tw_bucket *tw);
/* Socket demux engine toys. */
#ifdef __BIG_ENDIAN
#define TCP_COMBINED_PORTS(__sport, __dport) \
(((__u32)(__sport)<<16) | (__u32)(__dport))
#else /* __LITTLE_ENDIAN */
#define TCP_COMBINED_PORTS(__sport, __dport) \
(((__u32)(__dport)<<16) | (__u32)(__sport))
#endif
#if (BITS_PER_LONG == 64)
#ifdef __BIG_ENDIAN
#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
__u64 __name = (((__u64)(__saddr))<<32)|((__u64)(__daddr));
#else /* __LITTLE_ENDIAN */
#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
__u64 __name = (((__u64)(__daddr))<<32)|((__u64)(__saddr));
#endif /* __BIG_ENDIAN */
#define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
(((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \
((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
(((*((__u64 *)&(tcptw_sk(__sk)->tw_daddr))) == (__cookie)) && \
((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#else /* 32-bit arch */
#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr)
#define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
((inet_sk(__sk)->daddr == (__saddr)) && \
(inet_sk(__sk)->rcv_saddr == (__daddr)) && \
((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
((tcptw_sk(__sk)->tw_daddr == (__saddr)) && \
(tcptw_sk(__sk)->tw_rcv_saddr == (__daddr)) && \
((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#endif /* 64-bit arch */
#define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \
(((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
((__sk)->sk_family == AF_INET6) && \
ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr)) && \
ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
/* These can have wildcards, don't try too hard. */
static __inline__ int tcp_lhashfn(unsigned short num)
{
return num & (TCP_LHTABLE_SIZE - 1);
}
static __inline__ int tcp_sk_listen_hashfn(struct sock *sk)
{
return tcp_lhashfn(inet_sk(sk)->num);
}
#define MAX_TCP_HEADER (128 + MAX_HEADER)
/*
* Never offer a window over 32767 without using window scaling. Some
* poor stacks do signed 16bit maths!
*/
#define MAX_TCP_WINDOW 32767U
/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
#define TCP_MIN_MSS 88U
/* Minimal RCV_MSS. */
#define TCP_MIN_RCVMSS 536U
/* After receiving this amount of duplicate ACKs fast retransmit starts. */
#define TCP_FASTRETRANS_THRESH 3
/* Maximal reordering. */
#define TCP_MAX_REORDERING 127
/* Maximal number of ACKs sent quickly to accelerate slow-start. */
#define TCP_MAX_QUICKACKS 16U
/* urg_data states */
#define TCP_URG_VALID 0x0100
#define TCP_URG_NOTYET 0x0200
#define TCP_URG_READ 0x0400
#define TCP_RETR1 3 /*
* This is how many retries it does before it
* tries to figure out if the gateway is
* down. Minimal RFC value is 3; it corresponds
* to ~3sec-8min depending on RTO.
*/
#define TCP_RETR2 15 /*
* This should take at least
* 90 minutes to time out.
* RFC1122 says that the limit is 100 sec.
* 15 is ~13-30min depending on RTO.
*/
#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
* connection: ~180sec is RFC minumum */
#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
* connection: ~180sec is RFC minumum */
#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
* socket. 7 is ~50sec-16min.
*/
#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
* state, about 60 seconds */
#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
/* BSD style FIN_WAIT2 deadlock breaker.
* It used to be 3min, new value is 60sec,
* to combine FIN-WAIT-2 timeout with
* TIME-WAIT timer.
*/
#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
#if HZ >= 100
#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
#define TCP_ATO_MIN ((unsigned)(HZ/25))
#else
#define TCP_DELACK_MIN 4U
#define TCP_ATO_MIN 4U
#endif
#define TCP_RTO_MAX ((unsigned)(120*HZ))
#define TCP_RTO_MIN ((unsigned)(HZ/5))
#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
* for local resources.
*/
#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
#define TCP_KEEPALIVE_INTVL (75*HZ)
#define MAX_TCP_KEEPIDLE 32767
#define MAX_TCP_KEEPINTVL 32767
#define MAX_TCP_KEEPCNT 127
#define MAX_TCP_SYNCNT 127
#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
* after this time. It should be equal
* (or greater than) TCP_TIMEWAIT_LEN
* to provide reliability equal to one
* provided by timewait state.
*/
#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
* timestamps. It must be less than
* minimal timewait lifetime.
*/
#define TCP_TW_RECYCLE_SLOTS_LOG 5
#define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG)
/* If time > 4sec, it is "slow" path, no recycling is required,
so that we select tick to get range about 4 seconds.
*/
#if HZ <= 16 || HZ > 4096
# error Unsupported: HZ <= 16 or HZ > 4096
#elif HZ <= 32
# define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 64
# define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 128
# define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 256
# define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 512
# define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 1024
# define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
#elif HZ <= 2048
# define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
#else
# define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
#endif
/*
* TCP option
*/
#define TCPOPT_NOP 1 /* Padding */
#define TCPOPT_EOL 0 /* End of options */
#define TCPOPT_MSS 2 /* Segment size negotiating */
#define TCPOPT_WINDOW 3 /* Window scaling */
#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
#define TCPOPT_SACK 5 /* SACK Block */
#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
/*
* TCP option lengths
*/
#define TCPOLEN_MSS 4
#define TCPOLEN_WINDOW 3
#define TCPOLEN_SACK_PERM 2
#define TCPOLEN_TIMESTAMP 10
/* But this is what stacks really send out. */
#define TCPOLEN_TSTAMP_ALIGNED 12
#define TCPOLEN_WSCALE_ALIGNED 4
#define TCPOLEN_SACKPERM_ALIGNED 4
#define TCPOLEN_SACK_BASE 2
#define TCPOLEN_SACK_BASE_ALIGNED 4
#define TCPOLEN_SACK_PERBLOCK 8
#define TCP_TIME_RETRANS 1 /* Retransmit timer */
#define TCP_TIME_DACK 2 /* Delayed ack timer */
#define TCP_TIME_PROBE0 3 /* Zero window probe timer */
#define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */
/* Flags in tp->nonagle */
#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
#define TCP_NAGLE_CORK 2 /* Socket is corked */
#define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */
/* sysctl variables for tcp */
extern int sysctl_tcp_timestamps;
extern int sysctl_tcp_window_scaling;
extern int sysctl_tcp_sack;
extern int sysctl_tcp_fin_timeout;
extern int sysctl_tcp_tw_recycle;
extern int sysctl_tcp_keepalive_time;
extern int sysctl_tcp_keepalive_probes;
extern int sysctl_tcp_keepalive_intvl;
extern int sysctl_tcp_syn_retries;
extern int sysctl_tcp_synack_retries;
extern int sysctl_tcp_retries1;
extern int sysctl_tcp_retries2;
extern int sysctl_tcp_orphan_retries;
extern int sysctl_tcp_syncookies;
extern int sysctl_tcp_retrans_collapse;
extern int sysctl_tcp_stdurg;
extern int sysctl_tcp_rfc1337;
extern int sysctl_tcp_abort_on_overflow;
extern int sysctl_tcp_max_orphans;
extern int sysctl_tcp_max_tw_buckets;
extern int sysctl_tcp_fack;
extern int sysctl_tcp_reordering;
extern int sysctl_tcp_ecn;
extern int sysctl_tcp_dsack;
extern int sysctl_tcp_mem[3];
extern int sysctl_tcp_wmem[3];
extern int sysctl_tcp_rmem[3];
extern int sysctl_tcp_app_win;
extern int sysctl_tcp_adv_win_scale;
extern int sysctl_tcp_tw_reuse;
extern int sysctl_tcp_frto;
extern int sysctl_tcp_low_latency;
extern int sysctl_tcp_nometrics_save;
extern int sysctl_tcp_moderate_rcvbuf;
extern int sysctl_tcp_tso_win_divisor;
extern atomic_t tcp_memory_allocated;
extern atomic_t tcp_sockets_allocated;
extern int tcp_memory_pressure;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#define TCP_INET_FAMILY(fam) ((fam) == AF_INET)
#else
#define TCP_INET_FAMILY(fam) 1
#endif
/*
* Pointers to address related TCP functions
* (i.e. things that depend on the address family)
*/
struct tcp_func {
int (*queue_xmit) (struct sk_buff *skb,
int ipfragok);
void (*send_check) (struct sock *sk,
struct tcphdr *th,
int len,
struct sk_buff *skb);
int (*rebuild_header) (struct sock *sk);
int (*conn_request) (struct sock *sk,
struct sk_buff *skb);
struct sock * (*syn_recv_sock) (struct sock *sk,
struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst);
int (*remember_stamp) (struct sock *sk);
__u16 net_header_len;
int (*setsockopt) (struct sock *sk,
int level,
int optname,
char __user *optval,
int optlen);
int (*getsockopt) (struct sock *sk,
int level,
int optname,
char __user *optval,
int __user *optlen);
void (*addr2sockaddr) (struct sock *sk,
struct sockaddr *);
int sockaddr_len;
};
/*
* The next routines deal with comparing 32 bit unsigned ints
* and worry about wraparound (automatic with unsigned arithmetic).
*/
static inline int before(__u32 seq1, __u32 seq2)
{
return (__s32)(seq1-seq2) < 0;
}
static inline int after(__u32 seq1, __u32 seq2)
{
return (__s32)(seq2-seq1) < 0;
}
/* is s2<=s1<=s3 ? */
static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
{
return seq3 - seq2 >= seq1 - seq2;
}
extern struct proto tcp_prot;
DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
#define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
#define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
#define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
#define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
#define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
#define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
extern void tcp_put_port(struct sock *sk);
extern void tcp_inherit_port(struct sock *sk, struct sock *child);
extern void tcp_v4_err(struct sk_buff *skb, u32);
extern void tcp_shutdown (struct sock *sk, int how);
extern int tcp_v4_rcv(struct sk_buff *skb);
extern int tcp_v4_remember_stamp(struct sock *sk);
extern int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw);
extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t size);
extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
extern int tcp_ioctl(struct sock *sk,
int cmd,
unsigned long arg);
extern int tcp_rcv_state_process(struct sock *sk,
struct sk_buff *skb,
struct tcphdr *th,
unsigned len);
extern int tcp_rcv_established(struct sock *sk,
struct sk_buff *skb,
struct tcphdr *th,
unsigned len);
extern void tcp_rcv_space_adjust(struct sock *sk);
enum tcp_ack_state_t
{
TCP_ACK_SCHED = 1,
TCP_ACK_TIMER = 2,
TCP_ACK_PUSHED= 4
};
static inline void tcp_schedule_ack(struct tcp_sock *tp)
{
tp->ack.pending |= TCP_ACK_SCHED;
}
static inline int tcp_ack_scheduled(struct tcp_sock *tp)
{
return tp->ack.pending&TCP_ACK_SCHED;
}
static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp, unsigned int pkts)
{
if (tp->ack.quick) {
if (pkts >= tp->ack.quick) {
tp->ack.quick = 0;
/* Leaving quickack mode we deflate ATO. */
tp->ack.ato = TCP_ATO_MIN;
} else
tp->ack.quick -= pkts;
}
}
extern void tcp_enter_quickack_mode(struct tcp_sock *tp);
static __inline__ void tcp_delack_init(struct tcp_sock *tp)
{
memset(&tp->ack, 0, sizeof(tp->ack));
}
static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
{
rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
}
enum tcp_tw_status
{
TCP_TW_SUCCESS = 0,
TCP_TW_RST = 1,
TCP_TW_ACK = 2,
TCP_TW_SYN = 3
};
extern enum tcp_tw_status tcp_timewait_state_process(struct tcp_tw_bucket *tw,
struct sk_buff *skb,
struct tcphdr *th,
unsigned len);
extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
struct request_sock *req,
struct request_sock **prev);
extern int tcp_child_process(struct sock *parent,
struct sock *child,
struct sk_buff *skb);
extern void tcp_enter_frto(struct sock *sk);
extern void tcp_enter_loss(struct sock *sk, int how);
extern void tcp_clear_retrans(struct tcp_sock *tp);
extern void tcp_update_metrics(struct sock *sk);
extern void tcp_close(struct sock *sk,
long timeout);
extern struct sock * tcp_accept(struct sock *sk, int flags, int *err);
extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
extern int tcp_getsockopt(struct sock *sk, int level,
int optname,
char __user *optval,
int __user *optlen);
extern int tcp_setsockopt(struct sock *sk, int level,
int optname, char __user *optval,
int optlen);
extern void tcp_set_keepalive(struct sock *sk, int val);
extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg,
size_t len, int nonblock,
int flags, int *addr_len);
extern int tcp_listen_start(struct sock *sk);
extern void tcp_parse_options(struct sk_buff *skb,
struct tcp_options_received *opt_rx,
int estab);
/*
* TCP v4 functions exported for the inet6 API
*/
extern int tcp_v4_rebuild_header(struct sock *sk);
extern int tcp_v4_build_header(struct sock *sk,
struct sk_buff *skb);
extern void tcp_v4_send_check(struct sock *sk,
struct tcphdr *th, int len,
struct sk_buff *skb);
extern int tcp_v4_conn_request(struct sock *sk,
struct sk_buff *skb);
extern struct sock * tcp_create_openreq_child(struct sock *sk,
struct request_sock *req,
struct sk_buff *skb);
extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst);
extern int tcp_v4_do_rcv(struct sock *sk,
struct sk_buff *skb);
extern int tcp_v4_connect(struct sock *sk,
struct sockaddr *uaddr,
int addr_len);
extern int tcp_connect(struct sock *sk);
extern struct sk_buff * tcp_make_synack(struct sock *sk,
struct dst_entry *dst,
struct request_sock *req);
extern int tcp_disconnect(struct sock *sk, int flags);
extern void tcp_unhash(struct sock *sk);
extern int tcp_v4_hash_connecting(struct sock *sk);
/* From syncookies.c */
extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
struct ip_options *opt);
extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
__u16 *mss);
/* tcp_output.c */
extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
unsigned int cur_mss, int nonagle);
extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp);
extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
extern void tcp_xmit_retransmit_queue(struct sock *);
extern void tcp_simple_retransmit(struct sock *);
extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
extern void tcp_send_probe0(struct sock *);
extern void tcp_send_partial(struct sock *);
extern int tcp_write_wakeup(struct sock *);
extern void tcp_send_fin(struct sock *sk);
extern void tcp_send_active_reset(struct sock *sk, int priority);
extern int tcp_send_synack(struct sock *);
extern void tcp_push_one(struct sock *, unsigned mss_now);
extern void tcp_send_ack(struct sock *sk);
extern void tcp_send_delayed_ack(struct sock *sk);
/* tcp_input.c */
extern void tcp_cwnd_application_limited(struct sock *sk);
/* tcp_timer.c */
extern void tcp_init_xmit_timers(struct sock *);
extern void tcp_clear_xmit_timers(struct sock *);
extern void tcp_delete_keepalive_timer(struct sock *);
extern void tcp_reset_keepalive_timer(struct sock *, unsigned long);
extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
extern unsigned int tcp_current_mss(struct sock *sk, int large);
#ifdef TCP_DEBUG
extern const char tcp_timer_bug_msg[];
#endif
/* tcp_diag.c */
extern void tcp_get_info(struct sock *, struct tcp_info *);
/* Read 'sendfile()'-style from a TCP socket */
typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
unsigned int, size_t);
extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
sk_read_actor_t recv_actor);
static inline void tcp_clear_xmit_timer(struct sock *sk, int what)
{
struct tcp_sock *tp = tcp_sk(sk);
switch (what) {
case TCP_TIME_RETRANS:
case TCP_TIME_PROBE0:
tp->pending = 0;
#ifdef TCP_CLEAR_TIMERS
sk_stop_timer(sk, &tp->retransmit_timer);
#endif
break;
case TCP_TIME_DACK:
tp->ack.blocked = 0;
tp->ack.pending = 0;
#ifdef TCP_CLEAR_TIMERS
sk_stop_timer(sk, &tp->delack_timer);
#endif
break;
default:
#ifdef TCP_DEBUG
printk(tcp_timer_bug_msg);
#endif
return;
};
}
/*
* Reset the retransmission timer
*/
static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when)
{
struct tcp_sock *tp = tcp_sk(sk);
if (when > TCP_RTO_MAX) {
#ifdef TCP_DEBUG
printk(KERN_DEBUG "reset_xmit_timer sk=%p %d when=0x%lx, caller=%p\n", sk, what, when, current_text_addr());
#endif
when = TCP_RTO_MAX;
}
switch (what) {
case TCP_TIME_RETRANS:
case TCP_TIME_PROBE0:
tp->pending = what;
tp->timeout = jiffies+when;
sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
break;
case TCP_TIME_DACK:
tp->ack.pending |= TCP_ACK_TIMER;
tp->ack.timeout = jiffies+when;
sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
break;
default:
#ifdef TCP_DEBUG
printk(tcp_timer_bug_msg);
#endif
return;
};
}
/* Initialize RCV_MSS value.
* RCV_MSS is an our guess about MSS used by the peer.
* We haven't any direct information about the MSS.
* It's better to underestimate the RCV_MSS rather than overestimate.
* Overestimations make us ACKing less frequently than needed.
* Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
*/
static inline void tcp_initialize_rcv_mss(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
unsigned int hint = min(tp->advmss, tp->mss_cache_std);
hint = min(hint, tp->rcv_wnd/2);
hint = min(hint, TCP_MIN_RCVMSS);
hint = max(hint, TCP_MIN_MSS);
tp->ack.rcv_mss = hint;
}
static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
{
tp->pred_flags = htonl((tp->tcp_header_len << 26) |
ntohl(TCP_FLAG_ACK) |
snd_wnd);
}
static __inline__ void tcp_fast_path_on(struct tcp_sock *tp)
{
__tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
}
static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp)
{
if (skb_queue_len(&tp->out_of_order_queue) == 0 &&
tp->rcv_wnd &&
atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
!tp->urg_data)
tcp_fast_path_on(tp);
}