Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/include/net/tcp.h b/include/net/tcp.h
new file mode 100644
index 0000000..503810a
--- /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 */