diff options
Diffstat (limited to 'include/net/tcp.h')
| -rw-r--r-- | include/net/tcp.h | 2022 |
1 files changed, 2022 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h new file mode 100644 index 00000000000..503810a70e2 --- /dev/null +++ b/include/net/tcp.h @@ -0,0 +1,2022 @@ +/* + * 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, <bir7@leland.Stanford.Edu> + * 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/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 + +#define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation + * max_cwnd = snd_cwnd * beta + */ +#define BICTCP_MAX_INCREMENT 32 /* + * Limit on the amount of + * increment allowed during + * binary search. + */ +#define BICTCP_FUNC_OF_MIN_INCR 11 /* + * log(B/Smin)/log(B/(B-1))+1, + * Smin:min increment + * B:log factor + */ +#define BICTCP_B 4 /* + * In binary search, + * go to point (max+min)/N + */ + +/* + * 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_max_syn_backlog; +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_westwood; +extern int sysctl_tcp_vegas_cong_avoid; +extern int sysctl_tcp_vegas_alpha; +extern int sysctl_tcp_vegas_beta; +extern int sysctl_tcp_vegas_gamma; +extern int sysctl_tcp_nometrics_save; +extern int sysctl_tcp_bic; +extern int sysctl_tcp_bic_fast_convergence; +extern int sysctl_tcp_bic_low_window; +extern int sysctl_tcp_bic_beta; +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; + +struct open_request; + +struct or_calltable { + int family; + int (*rtx_syn_ack) (struct sock *sk, struct open_request *req, struct dst_entry*); + void (*send_ack) (struct sk_buff *skb, struct open_request *req); + void (*destructor) (struct open_request *req); + void (*send_reset) (struct sk_buff *skb); +}; + +struct tcp_v4_open_req { + __u32 loc_addr; + __u32 rmt_addr; + struct ip_options *opt; +}; + +#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) +struct tcp_v6_open_req { + struct in6_addr loc_addr; + struct in6_addr rmt_addr; + struct sk_buff *pktopts; + int iif; +}; +#endif + +/* this structure is too big */ +struct open_request { + struct open_request *dl_next; /* Must be first member! */ + __u32 rcv_isn; + __u32 snt_isn; + __u16 rmt_port; + __u16 mss; + __u8 retrans; + __u8 __pad; + __u16 snd_wscale : 4, + rcv_wscale : 4, + tstamp_ok : 1, + sack_ok : 1, + wscale_ok : 1, + ecn_ok : 1, + acked : 1; + /* The following two fields can be easily recomputed I think -AK */ + __u32 window_clamp; /* window clamp at creation time */ + __u32 rcv_wnd; /* rcv_wnd offered first time */ + __u32 ts_recent; + unsigned long expires; + struct or_calltable *class; + struct sock *sk; + union { + struct tcp_v4_open_req v4_req; +#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) + struct tcp_v6_open_req v6_req; +#endif + } af; +}; + +/* SLAB cache for open requests. */ +extern kmem_cache_t *tcp_openreq_cachep; + +#define tcp_openreq_alloc() kmem_cache_alloc(tcp_openreq_cachep, SLAB_ATOMIC) +#define tcp_openreq_fastfree(req) kmem_cache_free(tcp_openreq_cachep, req) + +static inline void tcp_openreq_free(struct open_request *req) +{ + req->class->destructor(req); + tcp_openreq_fastfree(req); +} + +#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 open_request *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) +{ + if (tp->ack.quick && --tp->ack.quick == 0) { + /* Leaving quickack mode we deflate ATO. */ + tp->ack.ato = TCP_ATO_MIN; + } +} + +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 open_request *req, + struct open_request **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 open_request *req, + struct sk_buff *skb); + +extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, + struct sk_buff *skb, + struct open_request *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 open_request *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 int tcp_write_xmit(struct sock *, int nonagle); +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_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); +} + +/* Compute the actual receive window we are currently advertising. + * Rcv_nxt can be after the window if our peer push more data + * than the offered window. + */ +static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) +{ + s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; + + if (win < 0) + win = 0; + return (u32) win; +} + +/* Choose a new window, without checks for shrinking, and without + * scaling applied to the result. The caller does these things + * if necessary. This is a "raw" window selection. + */ +extern u32 __tcp_select_window(struct sock *sk); + +/* TCP timestamps are only 32-bits, this causes a slight + * complication on 64-bit systems since we store a snapshot + * of jiffies in the buffer control blocks below. We decidely + * only use of the low 32-bits of jiffies and hide the ugly + * casts with the following macro. + */ +#define tcp_time_stamp ((__u32)(jiffies)) + +/* This is what the send packet queueing engine uses to pass + * TCP per-packet control information to the transmission + * code. We also store the host-order sequence numbers in + * here too. This is 36 bytes on 32-bit architectures, + * 40 bytes on 64-bit machines, if this grows please adjust + * skbuff.h:skbuff->cb[xxx] size appropriately. + */ +struct tcp_skb_cb { + union { + struct inet_skb_parm h4; +#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) + struct inet6_skb_parm h6; +#endif + } header; /* For incoming frames */ + __u32 seq; /* Starting sequence number */ + __u32 end_seq; /* SEQ + FIN + SYN + datalen */ + __u32 when; /* used to compute rtt's */ + __u8 flags; /* TCP header flags. */ + + /* NOTE: These must match up to the flags byte in a + * real TCP header. + */ +#define TCPCB_FLAG_FIN 0x01 +#define TCPCB_FLAG_SYN 0x02 +#define TCPCB_FLAG_RST 0x04 +#define TCPCB_FLAG_PSH 0x08 +#define TCPCB_FLAG_ACK 0x10 +#define TCPCB_FLAG_URG 0x20 +#define TCPCB_FLAG_ECE 0x40 +#define TCPCB_FLAG_CWR 0x80 + + __u8 sacked; /* State flags for SACK/FACK. */ +#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ +#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ +#define TCPCB_LOST 0x04 /* SKB is lost */ +#define TCPCB_TAGBITS 0x07 /* All tag bits */ + +#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ +#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) + +#define TCPCB_URG 0x20 /* Urgent pointer advenced here */ + +#define TCPCB_AT_TAIL (TCPCB_URG) + + __u16 urg_ptr; /* Valid w/URG flags is set. */ + __u32 ack_seq; /* Sequence number ACK'd */ +}; + +#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) + +#include <net/tcp_ecn.h> + +/* Due to TSO, an SKB can be composed of multiple actual + * packets. To keep these tracked properly, we use this. + */ +static inline int tcp_skb_pcount(const struct sk_buff *skb) +{ + return skb_shinfo(skb)->tso_segs; +} + +/* This is valid iff tcp_skb_pcount() > 1. */ +static inline int tcp_skb_mss(const struct sk_buff *skb) +{ + return skb_shinfo(skb)->tso_size; +} + +static inline void tcp_dec_pcount_approx(__u32 *count, + const struct sk_buff *skb) +{ + if (*count) { + *count -= tcp_skb_pcount(skb); + if ((int)*count < 0) + *count = 0; + } +} + +static inline void tcp_packets_out_inc(struct sock *sk, + struct tcp_sock *tp, + const struct sk_buff *skb) +{ + int orig = tp->packets_out; + + tp->packets_out += tcp_skb_pcount(skb); + if (!orig) + tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto); +} + +static inline void tcp_packets_out_dec(struct tcp_sock *tp, + const struct sk_buff *skb) +{ + tp->packets_out -= tcp_skb_pcount(skb); +} + +/* This determines how many packets are "in the network" to the best + * of our knowledge. In many cases it is conservative, but where + * detailed information is available from the receiver (via SACK + * blocks etc.) we can make more aggressive calculations. + * + * Use this for decisions involving congestion control, use just + * tp->packets_out to determine if the send queue is empty or not. + * + * Read this equation as: + * + * "Packets sent once on transmission queue" MINUS + * "Packets left network, but not honestly ACKed yet" PLUS + * "Packets fast retransmitted" + */ +static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) +{ + return (tp->packets_out - tp->left_out + tp->retrans_out); +} + +/* + * Which congestion algorithim is in use on the connection. + */ +#define tcp_is_vegas(__tp) ((__tp)->adv_cong == TCP_VEGAS) +#define tcp_is_westwood(__tp) ((__tp)->adv_cong == TCP_WESTWOOD) +#define tcp_is_bic(__tp) ((__tp)->adv_cong == TCP_BIC) + +/* Recalculate snd_ssthresh, we want to set it to: + * + * Reno: + * one half the current congestion window, but no + * less than two segments + * + * BIC: + * behave like Reno until low_window is reached, + * then increase congestion window slowly + */ +static inline __u32 tcp_recalc_ssthresh(struct tcp_sock *tp) +{ + if (tcp_is_bic(tp)) { + if (sysctl_tcp_bic_fast_convergence && + tp->snd_cwnd < tp->bictcp.last_max_cwnd) + tp->bictcp.last_max_cwnd = (tp->snd_cwnd * + (BICTCP_BETA_SCALE + + sysctl_tcp_bic_beta)) + / (2 * BICTCP_BETA_SCALE); + else + tp->bictcp.last_max_cwnd = tp->snd_cwnd; + + if (tp->snd_cwnd > sysctl_tcp_bic_low_window) + return max((tp->snd_cwnd * sysctl_tcp_bic_beta) + / BICTCP_BETA_SCALE, 2U); + } + + return max(tp->snd_cwnd >> 1U, 2U); +} + +/* Stop taking Vegas samples for now. */ +#define tcp_vegas_disable(__tp) ((__tp)->vegas.doing_vegas_now = 0) + +static inline void tcp_vegas_enable(struct tcp_sock *tp) +{ + /* There are several situations when we must "re-start" Vegas: + * + * o when a connection is established + * o after an RTO + * o after fast recovery + * o when we send a packet and there is no outstanding + * unacknowledged data (restarting an idle connection) + * + * In these circumstances we cannot do a Vegas calculation at the + * end of the first RTT, because any calculation we do is using + * stale info -- both the saved cwnd and congestion feedback are + * stale. + * + * Instead we must wait until the completion of an RTT during + * which we actually receive ACKs. + */ + + /* Begin taking Vegas samples next time we send something. */ + tp->vegas.doing_vegas_now = 1; + + /* Set the beginning of the next send window. */ + tp->vegas.beg_snd_nxt = tp->snd_nxt; + + tp->vegas.cntRTT = 0; + tp->vegas.minRTT = 0x7fffffff; +} + +/* Should we be taking Vegas samples right now? */ +#define tcp_vegas_enabled(__tp) ((__tp)->vegas.doing_vegas_now) + +extern void tcp_ca_init(struct tcp_sock *tp); + +static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state) +{ + if (tcp_is_vegas(tp)) { + if (ca_state == TCP_CA_Open) + tcp_vegas_enable(tp); + else + tcp_vegas_disable(tp); + } + tp->ca_state = ca_state; +} + +/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. + * The exception is rate halving phase, when cwnd is decreasing towards + * ssthresh. + */ +static inline __u32 tcp_current_ssthresh(struct tcp_sock *tp) +{ + if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery)) + return tp->snd_ssthresh; + else + return max(tp->snd_ssthresh, + ((tp->snd_cwnd >> 1) + + (tp->snd_cwnd >> 2))); +} + +static inline void tcp_sync_left_out(struct tcp_sock *tp) +{ + if (tp->rx_opt.sack_ok && + (tp->sacked_out >= tp->packets_out - tp->lost_out)) + tp->sacked_out = tp->packets_out - tp->lost_out; + tp->left_out = tp->sacked_out + tp->lost_out; +} + +extern void tcp_cwnd_application_limited(struct sock *sk); + +/* Congestion window validation. (RFC2861) */ + +static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp) +{ + __u32 packets_out = tp->packets_out; + + if (packets_out >= tp->snd_cwnd) { + /* Network is feed fully. */ + tp->snd_cwnd_used = 0; + tp->snd_cwnd_stamp = tcp_time_stamp; + } else { + /* Network starves. */ + if (tp->packets_out > tp->snd_cwnd_used) + tp->snd_cwnd_used = tp->packets_out; + + if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto) + tcp_cwnd_application_limited(sk); + } +} + +/* Set slow start threshould and cwnd not falling to slow start */ +static inline void __tcp_enter_cwr(struct tcp_sock *tp) +{ + tp->undo_marker = 0; + tp->snd_ssthresh = tcp_recalc_ssthresh(tp); + tp->snd_cwnd = min(tp->snd_cwnd, + tcp_packets_in_flight(tp) + 1U); + tp->snd_cwnd_cnt = 0; + tp->high_seq = tp->snd_nxt; + tp->snd_cwnd_stamp = tcp_time_stamp; + TCP_ECN_queue_cwr(tp); +} + +static inline void tcp_enter_cwr(struct tcp_sock *tp) +{ + tp->prior_ssthresh = 0; + if (tp->ca_state < TCP_CA_CWR) { + __tcp_enter_cwr(tp); + tcp_set_ca_state(tp, TCP_CA_CWR); + } +} + +extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); + +/* Slow start with delack produces 3 packets of burst, so that + * it is safe "de facto". + */ +static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) +{ + return 3; +} + +static __inline__ int tcp_minshall_check(const struct tcp_sock *tp) +{ + return after(tp->snd_sml,tp->snd_una) && + !after(tp->snd_sml, tp->snd_nxt); +} + +static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, + const struct sk_buff *skb) +{ + if (skb->len < mss) + tp->snd_sml = TCP_SKB_CB(skb)->end_seq; +} + +/* Return 0, if packet can be sent now without violation Nagle's rules: + 1. It is full sized. + 2. Or it contains FIN. + 3. Or TCP_NODELAY was set. + 4. Or TCP_CORK is not set, and all sent packets are ACKed. + With Minshall's modification: all sent small packets are ACKed. + */ + +static __inline__ int +tcp_nagle_check(const struct tcp_sock *tp, const struct sk_buff *skb, + unsigned mss_now, int nonagle) +{ + return (skb->len < mss_now && + !(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) && + ((nonagle&TCP_NAGLE_CORK) || + (!nonagle && + tp->packets_out && + tcp_minshall_check(tp)))); +} + +extern void tcp_set_skb_tso_segs(struct sk_buff *, unsigned int); + +/* This checks if the data bearing packet SKB (usually sk->sk_send_head) + * should be put on the wire right now. + */ +static __inline__ int tcp_snd_test(const struct tcp_sock *tp, + struct sk_buff *skb, + unsigned cur_mss, int nonagle) +{ + int pkts = tcp_skb_pcount(skb); + + if (!pkts) { + tcp_set_skb_tso_segs(skb, tp->mss_cache_std); + pkts = tcp_skb_pcount(skb); + } + + /* RFC 1122 - section 4.2.3.4 + * + * We must queue if + * + * a) The right edge of this frame exceeds the window + * b) There are packets in flight and we have a small segment + * [SWS avoidance and Nagle algorithm] + * (part of SWS is done on packetization) + * Minshall version sounds: there are no _small_ + * segments in flight. (tcp_nagle_check) + * c) We have too many packets 'in flight' + * + * Don't use the nagle rule for urgent data (or + * for the final FIN -DaveM). + * + * Also, Nagle rule does not apply to frames, which + * sit in the middle of queue (they have no chances + * to get new data) and if room at tail of skb is + * not enough to save something seriously (<32 for now). + */ + + /* Don't be strict about the congestion window for the + * final FIN frame. -DaveM + */ + return (((nonagle&TCP_NAGLE_PUSH) || tp->urg_mode + || !tcp_nagle_check(tp, skb, cur_mss, nonagle)) && + (((tcp_packets_in_flight(tp) + (pkts-1)) < tp->snd_cwnd) || + (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) && + !after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd)); +} + +static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) +{ + if (!tp->packets_out && !tp->pending) + tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto); +} + +static __inline__ int tcp_skb_is_last(const struct sock *sk, + const struct sk_buff *skb) +{ + return skb->next == (struct sk_buff *)&sk->sk_write_queue; +} + +/* Push out any pending frames which were held back due to + * TCP_CORK or attempt at coalescing tiny packets. + * The socket must be locked by the caller. + */ +static __inline__ void __tcp_push_pending_frames(struct sock *sk, + struct tcp_sock *tp, + unsigned cur_mss, + int nonagle) +{ + struct sk_buff *skb = sk->sk_send_head; + + if (skb) { + if (!tcp_skb_is_last(sk, skb)) + nonagle = TCP_NAGLE_PUSH; + if (!tcp_snd_test(tp, skb, cur_mss, nonagle) || + tcp_write_xmit(sk, nonagle)) + tcp_check_probe_timer(sk, tp); + } + tcp_cwnd_validate(sk, tp); +} + +static __inline__ void tcp_push_pending_frames(struct sock *sk, + struct tcp_sock *tp) +{ + __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); +} + +static __inline__ int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp) +{ + struct sk_buff *skb = sk->sk_send_head; + + return (skb && + tcp_snd_test(tp, skb, tcp_current_mss(sk, 1), + tcp_skb_is_last(sk, skb) ? TCP_NAGLE_PUSH : tp->nonagle)); +} + +static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) +{ + tp->snd_wl1 = seq; +} + +static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) +{ + tp->snd_wl1 = seq; +} + +extern void tcp_destroy_sock(struct sock *sk); + + +/* + * Calculate(/check) TCP checksum + */ +static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, + unsigned long saddr, unsigned long daddr, + unsigned long base) +{ + return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); +} + +static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) +{ + return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); +} + +static __inline__ int tcp_checksum_complete(struct sk_buff *skb) +{ + return skb->ip_summed != CHECKSUM_UNNECESSARY && + __tcp_checksum_complete(skb); +} + +/* Prequeue for VJ style copy to user, combined with checksumming. */ + +static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) +{ + tp->ucopy.task = NULL; + tp->ucopy.len = 0; + tp->ucopy.memory = 0; + skb_queue_head_init(&tp->ucopy.prequeue); +} + +/* Packet is added to VJ-style prequeue for processing in process + * context, if a reader task is waiting. Apparently, this exciting + * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) + * failed somewhere. Latency? Burstiness? Well, at least now we will + * see, why it failed. 8)8) --ANK + * + * NOTE: is this not too big to inline? + */ +static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (!sysctl_tcp_low_latency && tp->ucopy.task) { + __skb_queue_tail(&tp->ucopy.prequeue, skb); + tp->ucopy.memory += skb->truesize; + if (tp->ucopy.memory > sk->sk_rcvbuf) { + struct sk_buff *skb1; + + BUG_ON(sock_owned_by_user(sk)); + + while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { + sk->sk_backlog_rcv(sk, skb1); + NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); + } + + tp->ucopy.memory = 0; + } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { + wake_up_interruptible(sk->sk_sleep); + if (!tcp_ack_scheduled(tp)) + tcp_reset_xmit_timer(sk, TCP_TIME_DACK, (3*TCP_RTO_MIN)/4); + } + return 1; + } + return 0; +} + + +#undef STATE_TRACE + +#ifdef STATE_TRACE +static const char *statename[]={ + "Unused","Established","Syn Sent","Syn Recv", + "Fin Wait 1","Fin Wait 2","Time Wait", "Close", + "Close Wait","Last ACK","Listen","Closing" +}; +#endif + +static __inline__ void tcp_set_state(struct sock *sk, int state) +{ + int oldstate = sk->sk_state; + + switch (state) { + case TCP_ESTABLISHED: + if (oldstate != TCP_ESTABLISHED) + TCP_INC_STATS(TCP_MIB_CURRESTAB); + break; + + case TCP_CLOSE: + if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) + TCP_INC_STATS(TCP_MIB_ESTABRESETS); + + sk->sk_prot->unhash(sk); + if (tcp_sk(sk)->bind_hash && + !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) + tcp_put_port(sk); + /* fall through */ + default: + if (oldstate==TCP_ESTABLISHED) + TCP_DEC_STATS(TCP_MIB_CURRESTAB); + } + + /* Change state AFTER socket is unhashed to avoid closed + * socket sitting in hash tables. + */ + sk->sk_state = state; + +#ifdef STATE_TRACE + SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); +#endif +} + +static __inline__ void tcp_done(struct sock *sk) +{ + tcp_set_state(sk, TCP_CLOSE); + tcp_clear_xmit_timers(sk); + + sk->sk_shutdown = SHUTDOWN_MASK; + + if (!sock_flag(sk, SOCK_DEAD)) + sk->sk_state_change(sk); + else + tcp_destroy_sock(sk); +} + +static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) +{ + rx_opt->dsack = 0; + rx_opt->eff_sacks = 0; + rx_opt->num_sacks = 0; +} + +static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) +{ + if (tp->rx_opt.tstamp_ok) { + *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | + (TCPOPT_NOP << 16) | + (TCPOPT_TIMESTAMP << 8) | + TCPOLEN_TIMESTAMP); + *ptr++ = htonl(tstamp); + *ptr++ = htonl(tp->rx_opt.ts_recent); + } + if (tp->rx_opt.eff_sacks) { + struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; + int this_sack; + + *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | + (TCPOPT_NOP << 16) | + (TCPOPT_SACK << 8) | + (TCPOLEN_SACK_BASE + + (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK))); + for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { + *ptr++ = htonl(sp[this_sack].start_seq); + *ptr++ = htonl(sp[this_sack].end_seq); + } + if (tp->rx_opt.dsack) { + tp->rx_opt.dsack = 0; + tp->rx_opt.eff_sacks--; + } + } +} + +/* Construct a tcp options header for a SYN or SYN_ACK packet. + * If this is every changed make sure to change the definition of + * MAX_SYN_SIZE to match the new maximum number of options that you + * can generate. + */ +static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, + int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) +{ + /* We always get an MSS option. + * The option bytes which will be seen in normal data + * packets should timestamps be used, must be in the MSS + * advertised. But we subtract them from tp->mss_cache so + * that calculations in tcp_sendmsg are simpler etc. + * So account for this fact here if necessary. If we + * don't do this correctly, as a receiver we won't + * recognize data packets as being full sized when we + * should, and thus we won't abide by the delayed ACK + * rules correctly. + * SACKs don't matter, we never delay an ACK when we + * have any of those going out. + */ + *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); + if (ts) { + if(sack) + *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | + (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); + else + *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); + *ptr++ = htonl(tstamp); /* TSVAL */ + *ptr++ = htonl(ts_recent); /* TSECR */ + } else if(sack) + *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); + if (offer_wscale) + *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); +} + +/* Determine a window scaling and initial window to offer. */ +extern void tcp_select_initial_window(int __space, __u32 mss, + __u32 *rcv_wnd, __u32 *window_clamp, + int wscale_ok, __u8 *rcv_wscale); + +static inline int tcp_win_from_space(int space) +{ + return sysctl_tcp_adv_win_scale<=0 ? + (space>>(-sysctl_tcp_adv_win_scale)) : + space - (space>>sysctl_tcp_adv_win_scale); +} + +/* Note: caller must be prepared to deal with negative returns */ +static inline int tcp_space(const struct sock *sk) +{ + return tcp_win_from_space(sk->sk_rcvbuf - + atomic_read(&sk->sk_rmem_alloc)); +} + +static inline int tcp_full_space(const struct sock *sk) +{ + return tcp_win_from_space(sk->sk_rcvbuf); +} + +static inline void tcp_acceptq_queue(struct sock *sk, struct open_request *req, + struct sock *child) +{ + struct tcp_sock *tp = tcp_sk(sk); + + req->sk = child; + sk_acceptq_added(sk); + + if (!tp->accept_queue_tail) { + tp->accept_queue = req; + } else { + tp->accept_queue_tail->dl_next = req; + } + tp->accept_queue_tail = req; + req->dl_next = NULL; +} + +struct tcp_listen_opt +{ + u8 max_qlen_log; /* log_2 of maximal queued SYNs */ + int qlen; + int qlen_young; + int clock_hand; + u32 hash_rnd; + struct open_request *syn_table[TCP_SYNQ_HSIZE]; +}; + +static inline void +tcp_synq_removed(struct sock *sk, struct open_request *req) +{ + struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt; + + if (--lopt->qlen == 0) + tcp_delete_keepalive_timer(sk); + if (req->retrans == 0) + lopt->qlen_young--; +} + +static inline void tcp_synq_added(struct sock *sk) +{ + struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt; + + if (lopt->qlen++ == 0) + tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT); + lopt->qlen_young++; +} + +static inline int tcp_synq_len(struct sock *sk) +{ + return tcp_sk(sk)->listen_opt->qlen; +} + +static inline int tcp_synq_young(struct sock *sk) +{ + return tcp_sk(sk)->listen_opt->qlen_young; +} + +static inline int tcp_synq_is_full(struct sock *sk) +{ + return tcp_synq_len(sk) >> tcp_sk(sk)->listen_opt->max_qlen_log; +} + +static inline void tcp_synq_unlink(struct tcp_sock *tp, struct open_request *req, + struct open_request **prev) +{ + write_lock(&tp->syn_wait_lock); + *prev = req->dl_next; + write_unlock(&tp->syn_wait_lock); +} + +static inline void tcp_synq_drop(struct sock *sk, struct open_request *req, + struct open_request **prev) +{ + tcp_synq_unlink(tcp_sk(sk), req, prev); + tcp_synq_removed(sk, req); + tcp_openreq_free(req); +} + +static __inline__ void tcp_openreq_init(struct open_request *req, + struct tcp_options_received *rx_opt, + struct sk_buff *skb) +{ + req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ + req->rcv_isn = TCP_SKB_CB(skb)->seq; + req->mss = rx_opt->mss_clamp; + req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; + req->tstamp_ok = rx_opt->tstamp_ok; + req->sack_ok = rx_opt->sack_ok; + req->snd_wscale = rx_opt->snd_wscale; + req->wscale_ok = rx_opt->wscale_ok; + req->acked = 0; + req->ecn_ok = 0; + req->rmt_port = skb->h.th->source; +} + +extern void tcp_enter_memory_pressure(void); + +extern void tcp_listen_wlock(void); + +/* - We may sleep inside this lock. + * - If sleeping is not required (or called from BH), + * use plain read_(un)lock(&tcp_lhash_lock). + */ + +static inline void tcp_listen_lock(void) +{ + /* read_lock synchronizes to candidates to writers */ + read_lock(&tcp_lhash_lock); + atomic_inc(&tcp_lhash_users); + read_unlock(&tcp_lhash_lock); +} + +static inline void tcp_listen_unlock(void) +{ + if (atomic_dec_and_test(&tcp_lhash_users)) + wake_up(&tcp_lhash_wait); +} + +static inline int keepalive_intvl_when(const struct tcp_sock *tp) +{ + return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; +} + +static inline int keepalive_time_when(const struct tcp_sock *tp) +{ + return tp->keepalive_time ? : sysctl_tcp_keepalive_time; +} + +static inline int tcp_fin_time(const struct tcp_sock *tp) +{ + int fin_timeout = tp->linger2 ? : sysctl_tcp_fin_timeout; + + if (fin_timeout < (tp->rto<<2) - (tp->rto>>1)) + fin_timeout = (tp->rto<<2) - (tp->rto>>1); + + return fin_timeout; +} + +static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) +{ + if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) + return 0; + if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) + return 0; + + /* RST segments are not recommended to carry timestamp, + and, if they do, it is recommended to ignore PAWS because + "their cleanup function should take precedence over timestamps." + Certainly, it is mistake. It is necessary to understand the reasons + of this constraint to relax it: if peer reboots, clock may go + out-of-sync and half-open connections will not be reset. + Actually, the problem would be not existing if all + the implementations followed draft about maintaining clock + via reboots. Linux-2.2 DOES NOT! + + However, we can relax time bounds for RST segments to MSL. + */ + if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) + return 0; + return 1; +} + +static inline void tcp_v4_setup_caps(struct sock *sk, struct dst_entry *dst) +{ + sk->sk_route_caps = dst->dev->features; + if (sk->sk_route_caps & NETIF_F_TSO) { + if (sock_flag(sk, SOCK_NO_LARGESEND) || dst->header_len) + sk->sk_route_caps &= ~NETIF_F_TSO; + } +} + +#define TCP_CHECK_TIMER(sk) do { } while (0) + +static inline int tcp_use_frto(const struct sock *sk) +{ + const struct tcp_sock *tp = tcp_sk(sk); + + /* F-RTO must be activated in sysctl and there must be some + * unsent new data, and the advertised window should allow + * sending it. + */ + return (sysctl_tcp_frto && sk->sk_send_head && + !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, + tp->snd_una + tp->snd_wnd)); +} + +static inline void tcp_mib_init(void) +{ + /* See RFC 2012 */ + TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); + TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); + TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); + TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); +} + +/* /proc */ +enum tcp_seq_states { + TCP_SEQ_STATE_LISTENING, + TCP_SEQ_STATE_OPENREQ, + TCP_SEQ_STATE_ESTABLISHED, + TCP_SEQ_STATE_TIME_WAIT, +}; + +struct tcp_seq_afinfo { + struct module *owner; + char *name; + sa_family_t family; + int (*seq_show) (struct seq_file *m, void *v); + struct file_operations *seq_fops; +}; + +struct tcp_iter_state { + sa_family_t family; + enum tcp_seq_states state; + struct sock *syn_wait_sk; + int bucket, sbucket, num, uid; + struct seq_operations seq_ops; +}; + +extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); +extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); + +/* TCP Westwood functions and constants */ + +#define TCP_WESTWOOD_INIT_RTT (20*HZ) /* maybe too conservative?! */ +#define TCP_WESTWOOD_RTT_MIN (HZ/20) /* 50ms */ + +static inline void tcp_westwood_update_rtt(struct tcp_sock *tp, __u32 rtt_seq) +{ + if (tcp_is_westwood(tp)) + tp->westwood.rtt = rtt_seq; +} + +static inline __u32 __tcp_westwood_bw_rttmin(const struct tcp_sock *tp) +{ + return max((tp->westwood.bw_est) * (tp->westwood.rtt_min) / + (__u32) (tp->mss_cache_std), + 2U); +} + +static inline __u32 tcp_westwood_bw_rttmin(const struct tcp_sock *tp) +{ + return tcp_is_westwood(tp) ? __tcp_westwood_bw_rttmin(tp) : 0; +} + +static inline int tcp_westwood_ssthresh(struct tcp_sock *tp) +{ + __u32 ssthresh = 0; + + if (tcp_is_westwood(tp)) { + ssthresh = __tcp_westwood_bw_rttmin(tp); + if (ssthresh) + tp->snd_ssthresh = ssthresh; + } + + return (ssthresh != 0); +} + +static inline int tcp_westwood_cwnd(struct tcp_sock *tp) +{ + __u32 cwnd = 0; + + if (tcp_is_westwood(tp)) { + cwnd = __tcp_westwood_bw_rttmin(tp); + if (cwnd) + tp->snd_cwnd = cwnd; + } + + return (cwnd != 0); +} +#endif /* _TCP_H */ |