summaryrefslogtreecommitdiff
path: root/release/src/linux/linux/include/net/tcp.h
diff options
context:
space:
mode:
Diffstat (limited to 'release/src/linux/linux/include/net/tcp.h')
-rw-r--r--release/src/linux/linux/include/net/tcp.h1822
1 files changed, 1822 insertions, 0 deletions
diff --git a/release/src/linux/linux/include/net/tcp.h b/release/src/linux/linux/include/net/tcp.h
new file mode 100644
index 00000000..6571f4b2
--- /dev/null
+++ b/release/src/linux/linux/include/net/tcp.h
@@ -0,0 +1,1822 @@
+/*
+ * 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/tcp.h>
+#include <linux/slab.h>
+#include <linux/cache.h>
+#include <net/checksum.h>
+#include <net/sock.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 sock *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->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 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->reuse && (newsk->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->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 tcp_bind_bucket *next;
+ struct sock *owners;
+ struct tcp_bind_bucket **pprev;
+};
+
+struct tcp_bind_hashbucket {
+ spinlock_t lock;
+ struct tcp_bind_bucket *chain;
+};
+
+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->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 sock *__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_unlock(struct sock *sk);
+extern int tcp_port_rover;
+extern struct sock *tcp_v4_lookup_listener(u32 addr, unsigned short hnum, int dif);
+
+/* These are AF independent. */
+static __inline__ int tcp_bhashfn(__u16 lport)
+{
+ return (lport & (tcp_bhash_size - 1));
+}
+
+/* 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 {
+ __u32 daddr;
+ __u32 rcv_saddr;
+ __u16 dport;
+ unsigned short num;
+ int bound_dev_if;
+ struct sock *next;
+ struct sock **pprev;
+ struct sock *bind_next;
+ struct sock **bind_pprev;
+ unsigned char state,
+ substate; /* "zapped" is replaced with "substate" */
+ __u16 sport;
+ unsigned short family;
+ unsigned char reuse,
+ rcv_wscale; /* It is also TW bucket specific */
+ atomic_t refcnt;
+
+ /* And these are ours. */
+ int hashent;
+ int timeout;
+ __u32 rcv_nxt;
+ __u32 snd_nxt;
+ __u32 rcv_wnd;
+ __u32 ts_recent;
+ long ts_recent_stamp;
+ unsigned long ttd;
+ struct tcp_bind_bucket *tb;
+ struct tcp_tw_bucket *next_death;
+ struct tcp_tw_bucket **pprev_death;
+
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+ struct in6_addr v6_daddr;
+ struct in6_addr v6_rcv_saddr;
+#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->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_timewait_kill(struct tcp_tw_bucket *tw);
+extern void tcp_tw_schedule(struct tcp_tw_bucket *tw, 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 *)&((__sk)->daddr)))== (__cookie)) && \
+ ((*((__u32 *)&((__sk)->dport)))== (__ports)) && \
+ (!((__sk)->bound_dev_if) || ((__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)\
+ (((__sk)->daddr == (__saddr)) && \
+ ((__sk)->rcv_saddr == (__daddr)) && \
+ ((*((__u32 *)&((__sk)->dport)))== (__ports)) && \
+ (!((__sk)->bound_dev_if) || ((__sk)->bound_dev_if == (__dif))))
+#endif /* 64-bit arch */
+
+#define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \
+ (((*((__u32 *)&((__sk)->dport)))== (__ports)) && \
+ ((__sk)->family == AF_INET6) && \
+ !ipv6_addr_cmp(&(__sk)->net_pinfo.af_inet6.daddr, (__saddr)) && \
+ !ipv6_addr_cmp(&(__sk)->net_pinfo.af_inet6.rcv_saddr, (__daddr)) && \
+ (!((__sk)->bound_dev_if) || ((__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(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
+
+/* TIME_WAIT reaping mechanism. */
+#define TCP_TWKILL_SLOTS 8 /* Please keep this a power of 2. */
+#define TCP_TWKILL_PERIOD (TCP_TIMEWAIT_LEN/TCP_TWKILL_SLOTS)
+
+#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
+#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
+
+#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
+#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
+ * after this time. It should be equal
+ * (or greater than) TCP_TIMEWAIT_LEN
+ * to provide reliability equal to one
+ * provided by timewait state.
+ */
+#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
+ * timestamps. It must be less than
+ * minimal timewait lifetime.
+ */
+
+#define TCP_TW_RECYCLE_SLOTS_LOG 5
+#define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG)
+
+/* If time > 4sec, it is "slow" path, no recycling is required,
+ so that we select tick to get range about 4 seconds.
+ */
+
+#if HZ <= 16 || HZ > 4096
+# error Unsupported: HZ <= 16 or HZ > 4096
+#elif HZ <= 32
+# define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 64
+# define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 128
+# define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 256
+# define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 512
+# define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 1024
+# define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 2048
+# define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#else
+# define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#endif
+
+/*
+ * TCP option
+ */
+
+#define TCPOPT_NOP 1 /* Padding */
+#define TCPOPT_EOL 0 /* End of options */
+#define TCPOPT_MSS 2 /* Segment size negotiating */
+#define TCPOPT_WINDOW 3 /* Window scaling */
+#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
+#define TCPOPT_SACK 5 /* SACK Block */
+#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
+
+/*
+ * TCP option lengths
+ */
+
+#define TCPOLEN_MSS 4
+#define TCPOLEN_WINDOW 3
+#define TCPOLEN_SACK_PERM 2
+#define TCPOLEN_TIMESTAMP 10
+
+/* But this is what stacks really send out. */
+#define TCPOLEN_TSTAMP_ALIGNED 12
+#define TCPOLEN_WSCALE_ALIGNED 4
+#define TCPOLEN_SACKPERM_ALIGNED 4
+#define TCPOLEN_SACK_BASE 2
+#define TCPOLEN_SACK_BASE_ALIGNED 4
+#define TCPOLEN_SACK_PERBLOCK 8
+
+#define TCP_TIME_RETRANS 1 /* Retransmit timer */
+#define TCP_TIME_DACK 2 /* Delayed ack timer */
+#define TCP_TIME_PROBE0 3 /* Zero window probe timer */
+#define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */
+
+/* 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 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)
+ *
+ * BUGGG_FUTURE: all the idea behind this struct is wrong.
+ * It mixes socket frontend with transport function.
+ * With port sharing between IPv6/v4 it gives the only advantage,
+ * only poor IPv6 needs to permanently recheck, that it
+ * is still IPv6 8)8) It must be cleaned up as soon as possible.
+ * --ANK (980802)
+ */
+
+struct tcp_func {
+ int (*queue_xmit) (struct sk_buff *skb);
+
+ 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 *optval,
+ int optlen);
+
+ int (*getsockopt) (struct sock *sk,
+ int level,
+ int optname,
+ char *optval,
+ int *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).
+ */
+
+extern __inline int before(__u32 seq1, __u32 seq2)
+{
+ return (__s32)(seq1-seq2) < 0;
+}
+
+extern __inline int after(__u32 seq1, __u32 seq2)
+{
+ return (__s32)(seq2-seq1) < 0;
+}
+
+
+/* is s2<=s1<=s3 ? */
+extern __inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
+{
+ return seq3 - seq2 >= seq1 - seq2;
+}
+
+
+extern struct proto tcp_prot;
+
+extern struct tcp_mib tcp_statistics[NR_CPUS*2];
+#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)
+
+extern void tcp_put_port(struct sock *sk);
+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 sock *sk, struct msghdr *msg, int 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);
+
+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_opt *tp)
+{
+ tp->ack.pending |= TCP_ACK_SCHED;
+}
+
+static inline int tcp_ack_scheduled(struct tcp_opt *tp)
+{
+ return tp->ack.pending&TCP_ACK_SCHED;
+}
+
+static __inline__ void tcp_dec_quickack_mode(struct tcp_opt *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_opt *tp);
+
+static __inline__ void tcp_delack_init(struct tcp_opt *tp)
+{
+ memset(&tp->ack, 0, sizeof(tp->ack));
+}
+
+static inline void tcp_clear_options(struct tcp_opt *tp)
+{
+ tp->tstamp_ok = tp->sack_ok = tp->wscale_ok = tp->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_loss(struct sock *sk, int how);
+extern void tcp_clear_retrans(struct tcp_opt *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 void tcp_write_space(struct sock *sk);
+
+extern int tcp_getsockopt(struct sock *sk, int level,
+ int optname, char *optval,
+ int *optlen);
+extern int tcp_setsockopt(struct sock *sk, int level,
+ int optname, char *optval,
+ int optlen);
+extern void tcp_set_keepalive(struct sock *sk, int val);
+extern int tcp_recvmsg(struct sock *sk,
+ struct msghdr *msg,
+ int 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_opt *tp,
+ 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 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 int tcp_transmit_skb(struct sock *, struct sk_buff *);
+extern void tcp_send_skb(struct sock *, struct sk_buff *, int force_queue, unsigned mss_now);
+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 int tcp_sync_mss(struct sock *sk, u32 pmtu);
+
+extern const char timer_bug_msg[];
+
+/* 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_opt *tp = &sk->tp_pinfo.af_tcp;
+
+ switch (what) {
+ case TCP_TIME_RETRANS:
+ case TCP_TIME_PROBE0:
+ tp->pending = 0;
+
+#ifdef TCP_CLEAR_TIMERS
+ if (timer_pending(&tp->retransmit_timer) &&
+ del_timer(&tp->retransmit_timer))
+ __sock_put(sk);
+#endif
+ break;
+ case TCP_TIME_DACK:
+ tp->ack.blocked = 0;
+ tp->ack.pending = 0;
+
+#ifdef TCP_CLEAR_TIMERS
+ if (timer_pending(&tp->delack_timer) &&
+ del_timer(&tp->delack_timer))
+ __sock_put(sk);
+#endif
+ break;
+ default:
+ printk(timer_bug_msg);
+ return;
+ };
+
+}
+
+/*
+ * Reset the retransmission timer
+ */
+static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when)
+{
+ struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
+
+ 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;
+ if (!mod_timer(&tp->retransmit_timer, tp->timeout))
+ sock_hold(sk);
+ break;
+
+ case TCP_TIME_DACK:
+ tp->ack.pending |= TCP_ACK_TIMER;
+ tp->ack.timeout = jiffies+when;
+ if (!mod_timer(&tp->delack_timer, tp->ack.timeout))
+ sock_hold(sk);
+ break;
+
+ default:
+ printk(KERN_DEBUG "bug: unknown timer value\n");
+ };
+}
+
+/* Compute the current effective MSS, taking SACKs and IP options,
+ * and even PMTU discovery events into account.
+ */
+
+static __inline__ unsigned int tcp_current_mss(struct sock *sk)
+{
+ struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
+ struct dst_entry *dst = __sk_dst_get(sk);
+ int mss_now = tp->mss_cache;
+
+ if (dst && dst->pmtu != tp->pmtu_cookie)
+ mss_now = tcp_sync_mss(sk, dst->pmtu);
+
+ if (tp->eff_sacks)
+ mss_now -= (TCPOLEN_SACK_BASE_ALIGNED +
+ (tp->eff_sacks * TCPOLEN_SACK_PERBLOCK));
+ return mss_now;
+}
+
+/* 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_opt *tp = &sk->tp_pinfo.af_tcp;
+ unsigned int hint = min(tp->advmss, tp->mss_cache);
+
+ 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_opt *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_opt *tp)
+{
+ __tcp_fast_path_on(tp, tp->snd_wnd>>tp->snd_wscale);
+}
+
+static inline void tcp_fast_path_check(struct sock *sk, struct tcp_opt *tp)
+{
+ if (skb_queue_len(&tp->out_of_order_queue) == 0 &&
+ tp->rcv_wnd &&
+ atomic_read(&sk->rmem_alloc) < 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(struct tcp_opt *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))
+
+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]))
+
+#define for_retrans_queue(skb, sk, tp) \
+ for (skb = (sk)->write_queue.next; \
+ (skb != (tp)->send_head) && \
+ (skb != (struct sk_buff *)&(sk)->write_queue); \
+ skb=skb->next)
+
+
+#include <net/tcp_ecn.h>
+
+
+/*
+ * Compute minimal free write space needed to queue new packets.
+ */
+static inline int tcp_min_write_space(struct sock *sk)
+{
+ return sk->wmem_queued/2;
+}
+
+static inline int tcp_wspace(struct sock *sk)
+{
+ return sk->sndbuf - sk->wmem_queued;
+}
+
+
+/* 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(struct tcp_opt *tp)
+{
+ return tp->packets_out - tp->left_out + tp->retrans_out;
+}
+
+/* Recalculate snd_ssthresh, we want to set it to:
+ *
+ * one half the current congestion window, but no
+ * less than two segments
+ */
+static inline __u32 tcp_recalc_ssthresh(struct tcp_opt *tp)
+{
+ return max(tp->snd_cwnd >> 1U, 2U);
+}
+
+/* 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_opt *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_opt *tp)
+{
+ if (tp->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_opt *tp)
+{
+ if (tp->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_opt *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_opt *tp)
+{
+ tp->prior_ssthresh = 0;
+ if (tp->ca_state < TCP_CA_CWR) {
+ __tcp_enter_cwr(tp);
+ tp->ca_state = TCP_CA_CWR;
+ }
+}
+
+extern __u32 tcp_init_cwnd(struct tcp_opt *tp);
+
+/* Slow start with delack produces 3 packets of burst, so that
+ * it is safe "de facto".
+ */
+static __inline__ __u32 tcp_max_burst(struct tcp_opt *tp)
+{
+ return 3;
+}
+
+static __inline__ int tcp_minshall_check(struct tcp_opt *tp)
+{
+ return after(tp->snd_sml,tp->snd_una) &&
+ !after(tp->snd_sml, tp->snd_nxt);
+}
+
+static __inline__ void tcp_minshall_update(struct tcp_opt *tp, int mss, 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(struct tcp_opt *tp, struct sk_buff *skb, unsigned mss_now, int nonagle)
+{
+ return (skb->len < mss_now &&
+ !(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
+ (nonagle == 2 ||
+ (!nonagle &&
+ tp->packets_out &&
+ tcp_minshall_check(tp))));
+}
+
+/* This checks if the data bearing packet SKB (usually tp->send_head)
+ * should be put on the wire right now.
+ */
+static __inline__ int tcp_snd_test(struct tcp_opt *tp, struct sk_buff *skb,
+ unsigned cur_mss, int nonagle)
+{
+ /* 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==1 || tp->urg_mode
+ || !tcp_nagle_check(tp, skb, cur_mss, nonagle)) &&
+ ((tcp_packets_in_flight(tp) < 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_opt *tp)
+{
+ if (!tp->packets_out && !tp->pending)
+ tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto);
+}
+
+static __inline__ int tcp_skb_is_last(struct sock *sk, struct sk_buff *skb)
+{
+ return (skb->next == (struct sk_buff*)&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_opt *tp,
+ unsigned cur_mss,
+ int nonagle)
+{
+ struct sk_buff *skb = tp->send_head;
+
+ if (skb) {
+ if (!tcp_skb_is_last(sk, skb))
+ nonagle = 1;
+ 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_opt *tp)
+{
+ __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk), tp->nonagle);
+}
+
+static __inline__ int tcp_may_send_now(struct sock *sk, struct tcp_opt *tp)
+{
+ struct sk_buff *skb = tp->send_head;
+
+ return (skb &&
+ tcp_snd_test(tp, skb, tcp_current_mss(sk),
+ tcp_skb_is_last(sk, skb) ? 1 : tp->nonagle));
+}
+
+static __inline__ void tcp_init_wl(struct tcp_opt *tp, u32 ack, u32 seq)
+{
+ tp->snd_wl1 = seq;
+}
+
+static __inline__ void tcp_update_wl(struct tcp_opt *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_opt *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_opt *tp = &sk->tp_pinfo.af_tcp;
+
+ if (tp->ucopy.task) {
+ __skb_queue_tail(&tp->ucopy.prequeue, skb);
+ tp->ucopy.memory += skb->truesize;
+ if (tp->ucopy.memory > sk->rcvbuf) {
+ struct sk_buff *skb1;
+
+ if (sk->lock.users)
+ out_of_line_bug();
+
+ while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
+ sk->backlog_rcv(sk, skb1);
+ NET_INC_STATS_BH(TCPPrequeueDropped);
+ }
+
+ tp->ucopy.memory = 0;
+ } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
+ wake_up_interruptible(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 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->state;
+
+ switch (state) {
+ case TCP_ESTABLISHED:
+ if (oldstate != TCP_ESTABLISHED)
+ TCP_INC_STATS(TcpCurrEstab);
+ break;
+
+ case TCP_CLOSE:
+ sk->prot->unhash(sk);
+ if (sk->prev && !(sk->userlocks&SOCK_BINDPORT_LOCK))
+ tcp_put_port(sk);
+ /* fall through */
+ default:
+ if (oldstate==TCP_ESTABLISHED)
+ tcp_statistics[smp_processor_id()*2+!in_softirq()].TcpCurrEstab--;
+ }
+
+ /* Change state AFTER socket is unhashed to avoid closed
+ * socket sitting in hash tables.
+ */
+ 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->shutdown = SHUTDOWN_MASK;
+
+ if (!sk->dead)
+ sk->state_change(sk);
+ else
+ tcp_destroy_sock(sk);
+}
+
+static __inline__ void tcp_sack_reset(struct tcp_opt *tp)
+{
+ tp->dsack = 0;
+ tp->eff_sacks = 0;
+ tp->num_sacks = 0;
+}
+
+static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_opt *tp, __u32 tstamp)
+{
+ if (tp->tstamp_ok) {
+ *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
+ (TCPOPT_NOP << 16) |
+ (TCPOPT_TIMESTAMP << 8) |
+ TCPOLEN_TIMESTAMP);
+ *ptr++ = htonl(tstamp);
+ *ptr++ = htonl(tp->ts_recent);
+ }
+ if (tp->eff_sacks) {
+ struct tcp_sack_block *sp = tp->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->eff_sacks * TCPOLEN_SACK_PERBLOCK)));
+ for(this_sack = 0; this_sack < tp->eff_sacks; this_sack++) {
+ *ptr++ = htonl(sp[this_sack].start_seq);
+ *ptr++ = htonl(sp[this_sack].end_seq);
+ }
+ if (tp->dsack) {
+ tp->dsack = 0;
+ tp->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.
+ * Based on the assumption that the given amount of space
+ * will be offered. Store the results in the tp structure.
+ * NOTE: for smooth operation initial space offering should
+ * be a multiple of mss if possible. We assume here that mss >= 1.
+ * This MUST be enforced by all callers.
+ */
+static inline void tcp_select_initial_window(int __space, __u32 mss,
+ __u32 *rcv_wnd,
+ __u32 *window_clamp,
+ int wscale_ok,
+ __u8 *rcv_wscale)
+{
+ unsigned int space = (__space < 0 ? 0 : __space);
+
+ /* If no clamp set the clamp to the max possible scaled window */
+ if (*window_clamp == 0)
+ (*window_clamp) = (65535 << 14);
+ space = min(*window_clamp, space);
+
+ /* Quantize space offering to a multiple of mss if possible. */
+ if (space > mss)
+ space = (space / mss) * mss;
+
+ /* NOTE: offering an initial window larger than 32767
+ * will break some buggy TCP stacks. We try to be nice.
+ * If we are not window scaling, then this truncates
+ * our initial window offering to 32k. There should also
+ * be a sysctl option to stop being nice.
+ */
+ (*rcv_wnd) = min(space, MAX_TCP_WINDOW);
+ (*rcv_wscale) = 0;
+ if (wscale_ok) {
+ /* See RFC1323 for an explanation of the limit to 14 */
+ while (space > 65535 && (*rcv_wscale) < 14) {
+ space >>= 1;
+ (*rcv_wscale)++;
+ }
+ if (*rcv_wscale && sysctl_tcp_app_win && space>=mss &&
+ space - max((space>>sysctl_tcp_app_win), mss>>*rcv_wscale) < 65536/2)
+ (*rcv_wscale)--;
+ }
+
+ /* Set initial window to value enough for senders,
+ * following RFC1414. Senders, not following this RFC,
+ * will be satisfied with 2.
+ */
+ if (mss > (1<<*rcv_wscale)) {
+ int init_cwnd = 4;
+ if (mss > 1460*3)
+ init_cwnd = 2;
+ else if (mss > 1460)
+ init_cwnd = 3;
+ if (*rcv_wnd > init_cwnd*mss)
+ *rcv_wnd = init_cwnd*mss;
+ }
+ /* Set the clamp no higher than max representable value */
+ (*window_clamp) = min(65535U << (*rcv_wscale), *window_clamp);
+}
+
+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(struct sock *sk)
+{
+ return tcp_win_from_space(sk->rcvbuf - atomic_read(&sk->rmem_alloc));
+}
+
+static inline int tcp_full_space( struct sock *sk)
+{
+ return tcp_win_from_space(sk->rcvbuf);
+}
+
+static inline void tcp_acceptq_removed(struct sock *sk)
+{
+ sk->ack_backlog--;
+}
+
+static inline void tcp_acceptq_added(struct sock *sk)
+{
+ sk->ack_backlog++;
+}
+
+static inline int tcp_acceptq_is_full(struct sock *sk)
+{
+ return sk->ack_backlog > sk->max_ack_backlog;
+}
+
+static inline void tcp_acceptq_queue(struct sock *sk, struct open_request *req,
+ struct sock *child)
+{
+ struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
+
+ req->sk = child;
+ tcp_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;
+ 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 = sk->tp_pinfo.af_tcp.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 = sk->tp_pinfo.af_tcp.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 sk->tp_pinfo.af_tcp.listen_opt->qlen;
+}
+
+static inline int tcp_synq_young(struct sock *sk)
+{
+ return sk->tp_pinfo.af_tcp.listen_opt->qlen_young;
+}
+
+static inline int tcp_synq_is_full(struct sock *sk)
+{
+ return tcp_synq_len(sk)>>sk->tp_pinfo.af_tcp.listen_opt->max_qlen_log;
+}
+
+static inline void tcp_synq_unlink(struct tcp_opt *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(&sk->tp_pinfo.af_tcp, req, prev);
+ tcp_synq_removed(sk, req);
+ tcp_openreq_free(req);
+}
+
+static __inline__ void tcp_openreq_init(struct open_request *req,
+ struct tcp_opt *tp,
+ struct sk_buff *skb)
+{
+ req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
+ req->rcv_isn = TCP_SKB_CB(skb)->seq;
+ req->mss = tp->mss_clamp;
+ req->ts_recent = tp->saw_tstamp ? tp->rcv_tsval : 0;
+ req->tstamp_ok = tp->tstamp_ok;
+ req->sack_ok = tp->sack_ok;
+ req->snd_wscale = tp->snd_wscale;
+ req->wscale_ok = tp->wscale_ok;
+ req->acked = 0;
+ req->ecn_ok = 0;
+ req->rmt_port = skb->h.th->source;
+}
+
+#define TCP_MEM_QUANTUM ((int)PAGE_SIZE)
+
+static inline void tcp_free_skb(struct sock *sk, struct sk_buff *skb)
+{
+ sk->tp_pinfo.af_tcp.queue_shrunk = 1;
+ sk->wmem_queued -= skb->truesize;
+ sk->forward_alloc += skb->truesize;
+ __kfree_skb(skb);
+}
+
+static inline void tcp_charge_skb(struct sock *sk, struct sk_buff *skb)
+{
+ sk->wmem_queued += skb->truesize;
+ sk->forward_alloc -= skb->truesize;
+}
+
+extern void __tcp_mem_reclaim(struct sock *sk);
+extern int tcp_mem_schedule(struct sock *sk, int size, int kind);
+
+static inline void tcp_mem_reclaim(struct sock *sk)
+{
+ if (sk->forward_alloc >= TCP_MEM_QUANTUM)
+ __tcp_mem_reclaim(sk);
+}
+
+static inline void tcp_enter_memory_pressure(void)
+{
+ if (!tcp_memory_pressure) {
+ NET_INC_STATS(TCPMemoryPressures);
+ tcp_memory_pressure = 1;
+ }
+}
+
+static inline void tcp_moderate_sndbuf(struct sock *sk)
+{
+ if (!(sk->userlocks&SOCK_SNDBUF_LOCK)) {
+ sk->sndbuf = min(sk->sndbuf, sk->wmem_queued/2);
+ sk->sndbuf = max(sk->sndbuf, SOCK_MIN_SNDBUF);
+ }
+}
+
+static inline struct sk_buff *tcp_alloc_pskb(struct sock *sk, int size, int mem, int gfp)
+{
+ struct sk_buff *skb = alloc_skb(size+MAX_TCP_HEADER, gfp);
+
+ if (skb) {
+ skb->truesize += mem;
+ if (sk->forward_alloc >= (int)skb->truesize ||
+ tcp_mem_schedule(sk, skb->truesize, 0)) {
+ skb_reserve(skb, MAX_TCP_HEADER);
+ return skb;
+ }
+ __kfree_skb(skb);
+ } else {
+ tcp_enter_memory_pressure();
+ tcp_moderate_sndbuf(sk);
+ }
+ return NULL;
+}
+
+static inline struct sk_buff *tcp_alloc_skb(struct sock *sk, int size, int gfp)
+{
+ return tcp_alloc_pskb(sk, size, 0, gfp);
+}
+
+static inline struct page * tcp_alloc_page(struct sock *sk)
+{
+ if (sk->forward_alloc >= (int)PAGE_SIZE ||
+ tcp_mem_schedule(sk, PAGE_SIZE, 0)) {
+ struct page *page = alloc_pages(sk->allocation, 0);
+ if (page)
+ return page;
+ }
+ tcp_enter_memory_pressure();
+ tcp_moderate_sndbuf(sk);
+ return NULL;
+}
+
+static inline void tcp_writequeue_purge(struct sock *sk)
+{
+ struct sk_buff *skb;
+
+ while ((skb = __skb_dequeue(&sk->write_queue)) != NULL)
+ tcp_free_skb(sk, skb);
+ tcp_mem_reclaim(sk);
+}
+
+extern void tcp_rfree(struct sk_buff *skb);
+
+static inline void tcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
+{
+ skb->sk = sk;
+ skb->destructor = tcp_rfree;
+ atomic_add(skb->truesize, &sk->rmem_alloc);
+ sk->forward_alloc -= skb->truesize;
+}
+
+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(struct tcp_opt *tp)
+{
+ return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
+}
+
+static inline int keepalive_time_when(struct tcp_opt *tp)
+{
+ return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
+}
+
+static inline int tcp_fin_time(struct tcp_opt *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(struct tcp_opt *tp, int rst)
+{
+ if ((s32)(tp->rcv_tsval - tp->ts_recent) >= 0)
+ return 0;
+ if (xtime.tv_sec >= tp->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 >= tp->ts_recent_stamp + TCP_PAWS_MSL)
+ return 0;
+ return 1;
+}
+
+#define TCP_CHECK_TIMER(sk) do { } while (0)
+
+#endif /* _TCP_H */
generated by cgit v1.2.3-54-g00ecf (git 2.45.1) at 2024-05-20 02:36:30 +0000