tcpcore.h

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/*
 * COPYRIGHT:   See COPYING in the top level directory
 * PROJECT:     ReactOS TCP/IP protocol driver
 * FILE:        include/tcpcore.h
 * PURPOSE:     Transmission Control Protocol definitions
 * REVISIONS:
 *   CSH 01/01-2003 Ported from linux kernel 2.4.20
 */

/*
 * 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.
 */

#pragma once

#include "tcpdef.h"


struct socket;



#if 1 /* skbuff */

#define HAVE_ALLOC_SKB      /* For the drivers to know */
#define HAVE_ALIGNABLE_SKB  /* Ditto 8)        */
#define SLAB_SKB        /* Slabified skbuffs       */

#define CHECKSUM_NONE 0
#define CHECKSUM_HW 1
#define CHECKSUM_UNNECESSARY 2

#define SKB_DATA_ALIGN(X)   (((X) + (SMP_CACHE_BYTES-1)) & ~(SMP_CACHE_BYTES-1))
#define SKB_MAX_ORDER(X,ORDER)  (((PAGE_SIZE<<(ORDER)) - (X) - sizeof(struct skb_shared_info))&~(SMP_CACHE_BYTES-1))
#define SKB_MAX_HEAD(X)     (SKB_MAX_ORDER((X),0))
#define SKB_MAX_ALLOC       (SKB_MAX_ORDER(0,2))

/* A. Checksumming of received packets by device.
 *
 *  NONE: device failed to checksum this packet.
 *      skb->csum is undefined.
 *
 *  UNNECESSARY: device parsed packet and wouldbe verified checksum.
 *      skb->csum is undefined.
 *        It is bad option, but, unfortunately, many of vendors do this.
 *        Apparently with secret goal to sell you new device, when you
 *        will add new protocol to your host. F.e. IPv6. 8)
 *
 *  HW: the most generic way. Device supplied checksum of _all_
 *      the packet as seen by netif_rx in skb->csum.
 *      NOTE: Even if device supports only some protocols, but
 *      is able to produce some skb->csum, it MUST use HW,
 *      not UNNECESSARY.
 *
 * B. Checksumming on output.
 *
 *  NONE: skb is checksummed by protocol or csum is not required.
 *
 *  HW: device is required to csum packet as seen by hard_start_xmit
 *  from skb->h.raw to the end and to record the checksum
 *  at skb->h.raw+skb->csum.
 *
 *  Device must show its capabilities in dev->features, set
 *  at device setup time.
 *  NETIF_F_HW_CSUM - it is clever device, it is able to checksum
 *            everything.
 *  NETIF_F_NO_CSUM - loopback or reliable single hop media.
 *  NETIF_F_IP_CSUM - device is dumb. It is able to csum only
 *            TCP/UDP over IPv4. Sigh. Vendors like this
 *            way by an unknown reason. Though, see comment above
 *            about CHECKSUM_UNNECESSARY. 8)
 *
 *  Any questions? No questions, good.      --ANK
 */

#ifdef __i386__
#define NET_CALLER(arg) (*(((void**)&arg)-1))
#else
#define NET_CALLER(arg) __builtin_return_address(0)
#endif

#ifdef CONFIG_NETFILTER
struct nf_conntrack {
    atomic_t use;
    void (*destroy)(struct nf_conntrack *);
};

struct nf_ct_info {
    struct nf_conntrack *master;
};
#endif

struct sk_buff_head {
    /* These two members must be first. */
    struct sk_buff  * next;
    struct sk_buff  * prev;

    __u32       qlen;
    spinlock_t  lock;
};

struct sk_buff;

#define MAX_SKB_FRAGS 6

typedef struct skb_frag_struct skb_frag_t;

struct skb_frag_struct
{
    struct page *page;
    __u16 page_offset;
    __u16 size;
};

/* This data is invariant across clones and lives at
 * the end of the header data, ie. at skb->end.
 */
struct skb_shared_info {
    atomic_t    dataref;
    unsigned int    nr_frags;
    struct sk_buff  *frag_list;
    skb_frag_t  frags[MAX_SKB_FRAGS];
};

struct sk_buff {
    /* These two members must be first. */
    struct sk_buff  * next;         /* Next buffer in list              */
    struct sk_buff  * prev;         /* Previous buffer in list          */

    struct sk_buff_head * list;     /* List we are on               */
    struct sock *sk;            /* Socket we are owned by           */
    struct timeval  stamp;          /* Time we arrived              */
    struct net_device   *dev;       /* Device we arrived on/are leaving by      */

    /* Transport layer header */
    union
    {
        struct tcphdr   *th;
        struct udphdr   *uh;
        struct icmphdr  *icmph;
        struct igmphdr  *igmph;
        struct iphdr    *ipiph;
        struct spxhdr   *spxh;
        unsigned char   *raw;
    } h;

    /* Network layer header */
    union
    {
        struct iphdr    *iph;
        struct ipv6hdr  *ipv6h;
        struct arphdr   *arph;
        struct ipxhdr   *ipxh;
        unsigned char   *raw;
    } nh;

    /* Link layer header */
    union
    {
        struct ethhdr   *ethernet;
        unsigned char   *raw;
    } mac;

    struct  dst_entry *dst;

    /*
     * This is the control buffer. It is free to use for every
     * layer. Please put your private variables there. If you
     * want to keep them across layers you have to do a skb_clone()
     * first. This is owned by whoever has the skb queued ATM.
     */
    char        cb[48];

    unsigned int    len;            /* Length of actual data            */
    unsigned int    data_len;
    unsigned int    csum;           /* Checksum                     */
    unsigned char   __unused,       /* Dead field, may be reused            */
            cloned,         /* head may be cloned (check refcnt to be sure). */
            pkt_type,       /* Packet class                 */
            ip_summed;      /* Driver fed us an IP checksum         */
    __u32       priority;       /* Packet queueing priority         */
    atomic_t    users;          /* User count - see datagram.c,tcp.c        */
    unsigned short  protocol;       /* Packet protocol from driver.         */
    unsigned short  security;       /* Security level of packet         */
    unsigned int    truesize;       /* Buffer size                  */

    unsigned char   *head;          /* Head of buffer               */
    unsigned char   *data;          /* Data head pointer                */
    unsigned char   *tail;          /* Tail pointer                 */
    unsigned char   *end;           /* End pointer                  */

    void        (*destructor)(struct sk_buff *);    /* Destruct function        */
#ifdef CONFIG_NETFILTER
    /* Can be used for communication between hooks. */
        unsigned long   nfmark;
    /* Cache info */
    __u32       nfcache;
    /* Associated connection, if any */
    struct nf_ct_info *nfct;
#ifdef CONFIG_NETFILTER_DEBUG
        unsigned int nf_debug;
#endif
#endif /*CONFIG_NETFILTER*/

#if defined(CONFIG_HIPPI)
    union{
        __u32   ifield;
    } private;
#endif

#ifdef CONFIG_NET_SCHED
       __u32           tc_index;               /* traffic control index */
#endif
};

#define SK_WMEM_MAX 65535
#define SK_RMEM_MAX 65535

#if 1
//#ifdef __KERNEL__
/*
 *  Handling routines are only of interest to the kernel
 */

extern void         __kfree_skb(struct sk_buff *skb);
extern struct sk_buff *     alloc_skb(unsigned int size, int priority);
extern void         kfree_skbmem(struct sk_buff *skb);
extern struct sk_buff *     skb_clone(struct sk_buff *skb, int priority);
extern struct sk_buff *     skb_copy(const struct sk_buff *skb, int priority);
extern struct sk_buff *     pskb_copy(struct sk_buff *skb, int gfp_mask);
extern int          pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, int gfp_mask);
extern struct sk_buff *     skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom);
extern struct sk_buff *     skb_copy_expand(const struct sk_buff *skb,
                        int newheadroom,
                        int newtailroom,
                        int priority);
#define dev_kfree_skb(a)    kfree_skb(a)
extern void skb_over_panic(struct sk_buff *skb, int len, void *here);
extern void skb_under_panic(struct sk_buff *skb, int len, void *here);

/* Internal */
#define skb_shinfo(SKB)     ((struct skb_shared_info *)((SKB)->end))

static __inline int skb_queue_empty(struct sk_buff_head *list)
{
    return (list->next == (struct sk_buff *) list);
}

static __inline struct sk_buff *skb_get(struct sk_buff *skb)
{
    atomic_inc(&skb->users);
    return skb;
}

/*
 * If users==1, we are the only owner and are can avoid redundant
 * atomic change.
 */

static __inline void kfree_skb(struct sk_buff *skb)
{
    if (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users))
        __kfree_skb(skb);
}

/* Use this if you didn't touch the skb state [for fast switching] */
static __inline void kfree_skb_fast(struct sk_buff *skb)
{
    if (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users))
        kfree_skbmem(skb);
}

static __inline int skb_cloned(struct sk_buff *skb)
{
    return skb->cloned && atomic_read(&skb_shinfo(skb)->dataref) != 1;
}

static __inline int skb_shared(struct sk_buff *skb)
{
    return (atomic_read(&skb->users) != 1);
}

static __inline struct sk_buff *skb_share_check(struct sk_buff *skb, int pri)
{
    if (skb_shared(skb)) {
        struct sk_buff *nskb;
        nskb = skb_clone(skb, pri);
        kfree_skb(skb);
        return nskb;
    }
    return skb;
}


/*
 *  Copy shared buffers into a new sk_buff. We effectively do COW on
 *  packets to handle cases where we have a local reader and forward
 *  and a couple of other messy ones. The normal one is tcpdumping
 *  a packet thats being forwarded.
 */

static __inline struct sk_buff *skb_unshare(struct sk_buff *skb, int pri)
{
    struct sk_buff *nskb;
    if(!skb_cloned(skb))
        return skb;
    nskb=skb_copy(skb, pri);
    kfree_skb(skb);     /* Free our shared copy */
    return nskb;
}

static __inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
{
    struct sk_buff *list = ((struct sk_buff *)list_)->next;
    if (list == (struct sk_buff *)list_)
        list = NULL;
    return list;
}

static __inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
{
    struct sk_buff *list = ((struct sk_buff *)list_)->prev;
    if (list == (struct sk_buff *)list_)
        list = NULL;
    return list;
}

static __inline __u32 skb_queue_len(struct sk_buff_head *list_)
{
    return(list_->qlen);
}

static __inline void skb_queue_head_init(struct sk_buff_head *list)
{
    spin_lock_init(&list->lock);
    list->prev = (struct sk_buff *)list;
    list->next = (struct sk_buff *)list;
    list->qlen = 0;
}

/*
 *  Insert an sk_buff at the start of a list.
 *
 *  The "__skb_xxxx()" functions are the non-atomic ones that
 *  can only be called with interrupts disabled.
 */

static __inline void __skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
{
    struct sk_buff *prev, *next;

    newsk->list = list;
    list->qlen++;
    prev = (struct sk_buff *)list;
    next = prev->next;
    newsk->next = next;
    newsk->prev = prev;
    next->prev = newsk;
    prev->next = newsk;
}


static __inline void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
{
    unsigned long flags;

    spin_lock_irqsave(&list->lock, flags);
    __skb_queue_head(list, newsk);
    spin_unlock_irqrestore(&list->lock, flags);
}

static __inline void __skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
{
    struct sk_buff *prev, *next;

    newsk->list = list;
    list->qlen++;
    next = (struct sk_buff *)list;
    prev = next->prev;
    newsk->next = next;
    newsk->prev = prev;
    next->prev = newsk;
    prev->next = newsk;
}

static __inline void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
{
    unsigned long flags;

    spin_lock_irqsave(&list->lock, flags);
    __skb_queue_tail(list, newsk);
    spin_unlock_irqrestore(&list->lock, flags);
}

static __inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
{
    struct sk_buff *next, *prev, *result;

    prev = (struct sk_buff *) list;
    next = prev->next;
    result = NULL;
    if (next != prev) {
        result = next;
        next = next->next;
        list->qlen--;
        next->prev = prev;
        prev->next = next;
        result->next = NULL;
        result->prev = NULL;
        result->list = NULL;
    }
    return result;
}

static __inline struct sk_buff *skb_dequeue(struct sk_buff_head *list)
{
    unsigned long flags;
    struct sk_buff *result;

    spin_lock_irqsave(&list->lock, flags);
    result = __skb_dequeue(list);
    spin_unlock_irqrestore(&list->lock, flags);
    return result;
}

/*
 *  Insert a packet on a list.
 */

static __inline void __skb_insert(struct sk_buff *newsk,
    struct sk_buff * prev, struct sk_buff *next,
    struct sk_buff_head * list)
{
    newsk->next = next;
    newsk->prev = prev;
    next->prev = newsk;
    prev->next = newsk;
    newsk->list = list;
    list->qlen++;
}

static __inline void skb_insert(struct sk_buff *old, struct sk_buff *newsk)
{
    unsigned long flags;

    spin_lock_irqsave(&old->list->lock, flags);
    __skb_insert(newsk, old->prev, old, old->list);
    spin_unlock_irqrestore(&old->list->lock, flags);
}

/*
 *  Place a packet after a given packet in a list.
 */

static __inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk)
{
    __skb_insert(newsk, old, old->next, old->list);
}

static __inline void skb_append(struct sk_buff *old, struct sk_buff *newsk)
{
    unsigned long flags;

    spin_lock_irqsave(&old->list->lock, flags);
    __skb_append(old, newsk);
    spin_unlock_irqrestore(&old->list->lock, flags);
}

/*
 * remove sk_buff from list. _Must_ be called atomically, and with
 * the list known..
 */

static __inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
{
    struct sk_buff * next, * prev;

    list->qlen--;
    next = skb->next;
    prev = skb->prev;
    skb->next = NULL;
    skb->prev = NULL;
    skb->list = NULL;
    next->prev = prev;
    prev->next = next;
}

static __inline void skb_unlink(struct sk_buff *skb)
{
    struct sk_buff_head *list = skb->list;

    if(list) {
        unsigned long flags;

        spin_lock_irqsave(&list->lock, flags);
        if(skb->list == list)
            __skb_unlink(skb, skb->list);
        spin_unlock_irqrestore(&list->lock, flags);
    }
}

/* XXX: more streamlined implementation */

static __inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
{
    struct sk_buff *skb = skb_peek_tail(list);
    if (skb)
        __skb_unlink(skb, list);
    return skb;
}

static __inline struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
{
    unsigned long flags;
    struct sk_buff *result;

    spin_lock_irqsave(&list->lock, flags);
    result = __skb_dequeue_tail(list);
    spin_unlock_irqrestore(&list->lock, flags);
    return result;
}

static __inline int skb_is_nonlinear(const struct sk_buff *skb)
{
    return skb->data_len;
}

static __inline int skb_headlen(const struct sk_buff *skb)
{
    return skb->len - skb->data_len;
}

#define SKB_PAGE_ASSERT(skb) do { if (skb_shinfo(skb)->nr_frags) out_of_line_bug(); } while (0)
#define SKB_FRAG_ASSERT(skb) do { if (skb_shinfo(skb)->frag_list) out_of_line_bug(); } while (0)
#define SKB_LINEAR_ASSERT(skb) do { if (skb_is_nonlinear(skb)) out_of_line_bug(); } while (0)

/*
 *  Add data to an sk_buff
 */

static __inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
{
    unsigned char *tmp=skb->tail;
    SKB_LINEAR_ASSERT(skb);
    skb->tail+=len;
    skb->len+=len;
    return tmp;
}

static __inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
{
#if 0
    unsigned char *tmp=skb->tail;
    SKB_LINEAR_ASSERT(skb);
    skb->tail+=len;
    skb->len+=len;
    if(skb->tail>skb->end) {
        skb_over_panic(skb, len, current_text_addr());
    }
    return tmp;
#else
return NULL;
#endif
}

static __inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
{
    skb->data-=len;
    skb->len+=len;
    return skb->data;
}

static __inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
{
#if 0
    skb->data-=len;
    skb->len+=len;
    if(skb->data<skb->head) {
        skb_under_panic(skb, len, current_text_addr());
    }
    return skb->data;
#else
  return NULL;
#endif
}

static __inline char *__skb_pull(struct sk_buff *skb, unsigned int len)
{
    skb->len-=len;
    if (skb->len < skb->data_len)
        out_of_line_bug();
    return  skb->data+=len;
}

static __inline unsigned char * skb_pull(struct sk_buff *skb, unsigned int len)
{
    if (len > skb->len)
        return NULL;
    return __skb_pull(skb,len);
}

extern unsigned char * __pskb_pull_tail(struct sk_buff *skb, int delta);

static __inline char *__pskb_pull(struct sk_buff *skb, unsigned int len)
{
    if (len > skb_headlen(skb) &&
        __pskb_pull_tail(skb, len-skb_headlen(skb)) == NULL)
        return NULL;
    skb->len -= len;
    return  skb->data += len;
}

static __inline unsigned char * pskb_pull(struct sk_buff *skb, unsigned int len)
{
    if (len > skb->len)
        return NULL;
    return __pskb_pull(skb,len);
}

static __inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
{
    if (len <= skb_headlen(skb))
        return 1;
    if (len > skb->len)
        return 0;
    return (__pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL);
}

static __inline int skb_headroom(const struct sk_buff *skb)
{
    return skb->data-skb->head;
}

static __inline int skb_tailroom(const struct sk_buff *skb)
{
    return skb_is_nonlinear(skb) ? 0 : skb->end-skb->tail;
}

static __inline void skb_reserve(struct sk_buff *skb, unsigned int len)
{
    skb->data+=len;
    skb->tail+=len;
}

extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);

static __inline void __skb_trim(struct sk_buff *skb, unsigned int len)
{
    if (!skb->data_len) {
        skb->len = len;
        skb->tail = skb->data+len;
    } else {
        ___pskb_trim(skb, len, 0);
    }
}

static __inline void skb_trim(struct sk_buff *skb, unsigned int len)
{
    if (skb->len > len) {
        __skb_trim(skb, len);
    }
}


static __inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
{
    if (!skb->data_len) {
        skb->len = len;
        skb->tail = skb->data+len;
        return 0;
    } else {
        return ___pskb_trim(skb, len, 1);
    }
}

static __inline int pskb_trim(struct sk_buff *skb, unsigned int len)
{
    if (len < skb->len)
        return __pskb_trim(skb, len);
    return 0;
}

static __inline void skb_orphan(struct sk_buff *skb)
{
    if (skb->destructor)
        skb->destructor(skb);
    skb->destructor = NULL;
    skb->sk = NULL;
}

static __inline void skb_queue_purge(struct sk_buff_head *list)
{
    struct sk_buff *skb;
    while ((skb=skb_dequeue(list))!=NULL)
        kfree_skb(skb);
}

static __inline void __skb_queue_purge(struct sk_buff_head *list)
{
    struct sk_buff *skb;
    while ((skb=__skb_dequeue(list))!=NULL)
        kfree_skb(skb);
}

static __inline struct sk_buff *__dev_alloc_skb(unsigned int length,
                          int gfp_mask)
{
    struct sk_buff *skb;

    skb = alloc_skb(length+16, gfp_mask);
    if (skb)
        skb_reserve(skb,16);
    return skb;
}

static __inline struct sk_buff *dev_alloc_skb(unsigned int length)
{
#if 0
    return __dev_alloc_skb(length, GFP_ATOMIC);
#else
  return NULL;
#endif
}

static __inline int
skb_cow(struct sk_buff *skb, unsigned int headroom)
{
#if 0
    int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb);

    if (delta < 0)
        delta = 0;

    if (delta || skb_cloned(skb))
        return pskb_expand_head(skb, (delta+15)&~15, 0, GFP_ATOMIC);
    return 0;
#else
  return 0;
#endif
}

int skb_linearize(struct sk_buff *skb, int gfp);

static __inline void *kmap_skb_frag(const skb_frag_t *frag)
{
#if 0
#ifdef CONFIG_HIGHMEM
    if (in_irq())
        out_of_line_bug();

    local_bh_disable();
#endif
    return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
#else
  return NULL;
#endif
}

static __inline void kunmap_skb_frag(void *vaddr)
{
#if 0
    kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
#ifdef CONFIG_HIGHMEM
    local_bh_enable();
#endif
#endif
}

#define skb_queue_walk(queue, skb) \
        for (skb = (queue)->next;           \
             (skb != (struct sk_buff *)(queue));    \
             skb=skb->next)


extern struct sk_buff *     skb_recv_datagram(struct sock *sk,unsigned flags,int noblock, int *err);
extern unsigned int     datagram_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait);
extern int          skb_copy_datagram(const struct sk_buff *from, int offset, char *to,int size);
extern int          skb_copy_datagram_iovec(const struct sk_buff *from, int offset, struct iovec *to,int size);
extern int          skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, u8 *to, int len, unsigned int *csump);
extern int          skb_copy_and_csum_datagram_iovec(const struct sk_buff *skb, int hlen, struct iovec *iov);
extern void         skb_free_datagram(struct sock * sk, struct sk_buff *skb);

extern unsigned int     skb_checksum(const struct sk_buff *skb, int offset, int len, unsigned int csum);
extern int          skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
extern unsigned int     skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to, int len, unsigned int csum);
extern void         skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);

extern void skb_init(void);
extern void skb_add_mtu(int mtu);

#ifdef CONFIG_NETFILTER
static __inline void
nf_conntrack_put(struct nf_ct_info *nfct)
{
    if (nfct && atomic_dec_and_test(&nfct->master->use))
        nfct->master->destroy(nfct->master);
}
static __inline void
nf_conntrack_get(struct nf_ct_info *nfct)
{
    if (nfct)
        atomic_inc(&nfct->master->use);
}
#endif


#endif /* skbuff */





struct sock;

typedef struct sockaddr
{
  int x;
} _sockaddr;


struct msghdr {
    void    *   msg_name;   /* Socket name          */
    int     msg_namelen;    /* Length of name       */
    struct iovec *  msg_iov;    /* Data blocks          */
    __kernel_size_t msg_iovlen; /* Number of blocks     */
    void    *   msg_control;    /* Per protocol magic (eg BSD file descriptor passing) */
    __kernel_size_t msg_controllen; /* Length of cmsg list */
    unsigned    msg_flags;
};


/* IP protocol blocks we attach to sockets.
 * socket layer -> transport layer interface
 * transport -> network interface is defined by struct inet_proto
 */
struct proto {
    void            (*close)(struct sock *sk,
                    long timeout);
    int         (*connect)(struct sock *sk,
                        struct sockaddr *uaddr,
                    int addr_len);
    int         (*disconnect)(struct sock *sk, int flags);

    struct sock *       (*accept) (struct sock *sk, int flags, int *err);

    int         (*ioctl)(struct sock *sk, int cmd,
                     unsigned long arg);
    int         (*init)(struct sock *sk);
    int         (*destroy)(struct sock *sk);
    void            (*shutdown)(struct sock *sk, int how);
    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 *option);
    int         (*sendmsg)(struct sock *sk, struct msghdr *msg,
                       int len);
    int         (*recvmsg)(struct sock *sk, struct msghdr *msg,
                    int len, int noblock, int flags,
                    int *addr_len);
    int         (*bind)(struct sock *sk,
                    struct sockaddr *uaddr, int addr_len);

    int         (*backlog_rcv) (struct sock *sk,
                        struct sk_buff *skb);

    /* Keeping track of sk's, looking them up, and port selection methods. */
    void            (*hash)(struct sock *sk);
    void            (*unhash)(struct sock *sk);
    int         (*get_port)(struct sock *sk, unsigned short snum);

    char            name[32];

    struct {
        int inuse;
  } stats[32];
//      u8  __pad[SMP_CACHE_BYTES - sizeof(int)];
//  } stats[NR_CPUS];
};







/* This defines a selective acknowledgement block. */
struct tcp_sack_block {
    __u32   start_seq;
    __u32   end_seq;
};


struct tcp_opt {
    int tcp_header_len; /* Bytes of tcp header to send      */

/*
 *  Header prediction flags
 *  0x5?10 << 16 + snd_wnd in net byte order
 */
    __u32   pred_flags;

/*
 *  RFC793 variables by their proper names. This means you can
 *  read the code and the spec side by side (and laugh ...)
 *  See RFC793 and RFC1122. The RFC writes these in capitals.
 */
    __u32   rcv_nxt;    /* What we want to receive next     */
    __u32   snd_nxt;    /* Next sequence we send        */

    __u32   snd_una;    /* First byte we want an ack for    */
    __u32   snd_sml;    /* Last byte of the most recently transmitted small packet */
    __u32   rcv_tstamp; /* timestamp of last received ACK (for keepalives) */
    __u32   lsndtime;   /* timestamp of last sent data packet (for restart window) */

    /* Delayed ACK control data */
    struct {
        __u8    pending;    /* ACK is pending */
        __u8    quick;      /* Scheduled number of quick acks   */
        __u8    pingpong;   /* The session is interactive       */
        __u8    blocked;    /* Delayed ACK was blocked by socket lock*/
        __u32   ato;        /* Predicted tick of soft clock     */
        unsigned long timeout;  /* Currently scheduled timeout      */
        __u32   lrcvtime;   /* timestamp of last received data packet*/
        __u16   last_seg_size;  /* Size of last incoming segment    */
        __u16   rcv_mss;    /* MSS used for delayed ACK decisions   */
    } ack;

    /* Data for direct copy to user */
    struct {
        //struct sk_buff_head   prequeue;
        struct task_struct  *task;
        struct iovec        *iov;
        int         memory;
        int         len;
    } ucopy;

    __u32   snd_wl1;    /* Sequence for window update       */
    __u32   snd_wnd;    /* The window we expect to receive  */
    __u32   max_window; /* Maximal window ever seen from peer   */
    __u32   pmtu_cookie;    /* Last pmtu seen by socket     */
    __u16   mss_cache;  /* Cached effective mss, not including SACKS */
    __u16   mss_clamp;  /* Maximal mss, negotiated at connection setup */
    __u16   ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
    __u8    ca_state;   /* State of fast-retransmit machine     */
    __u8    retransmits;    /* Number of unrecovered RTO timeouts.  */

    __u8    reordering; /* Packet reordering metric.        */
    __u8    queue_shrunk;   /* Write queue has been shrunk recently.*/
    __u8    defer_accept;   /* User waits for some data after accept() */

/* RTT measurement */
    __u8    backoff;    /* backoff              */
    __u32   srtt;       /* smoothed round trip time << 3        */
    __u32   mdev;       /* medium deviation         */
    __u32   mdev_max;   /* maximal mdev for the last rtt period */
    __u32   rttvar;     /* smoothed mdev_max            */
    __u32   rtt_seq;    /* sequence number to update rttvar */
    __u32   rto;        /* retransmit timeout           */

    __u32   packets_out;    /* Packets which are "in flight"    */
    __u32   left_out;   /* Packets which leaved network     */
    __u32   retrans_out;    /* Retransmitted packets out        */


/*
 *  Slow start and congestion control (see also Nagle, and Karn & Partridge)
 */
    __u32   snd_ssthresh;   /* Slow start size threshold        */
    __u32   snd_cwnd;   /* Sending congestion window        */
    __u16   snd_cwnd_cnt;   /* Linear increase counter      */
    __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
    __u32   snd_cwnd_used;
    __u32   snd_cwnd_stamp;

    /* Two commonly used timers in both sender and receiver paths. */
    unsigned long       timeout;
    struct timer_list   retransmit_timer;   /* Resend (no ack)  */
    struct timer_list   delack_timer;       /* Ack delay        */

    struct sk_buff_head out_of_order_queue; /* Out of order segments go here */

    struct tcp_func     *af_specific;   /* Operations which are AF_INET{4,6} specific   */
    struct sk_buff      *send_head; /* Front of stuff to transmit           */
    struct page     *sndmsg_page;   /* Cached page for sendmsg          */
    u32         sndmsg_off; /* Cached offset for sendmsg            */

    __u32   rcv_wnd;    /* Current receiver window      */
    __u32   rcv_wup;    /* rcv_nxt on last window update sent   */
    __u32   write_seq;  /* Tail(+1) of data held in tcp send buffer */
    __u32   pushed_seq; /* Last pushed seq, required to talk to windows */
    __u32   copied_seq; /* Head of yet unread data      */
/*
 *      Options received (usually on last packet, some only on SYN packets).
 */
    char    tstamp_ok,  /* TIMESTAMP seen on SYN packet     */
        wscale_ok,  /* Wscale seen on SYN packet        */
        sack_ok;    /* SACK seen on SYN packet      */
    char    saw_tstamp; /* Saw TIMESTAMP on last packet     */
        __u8    snd_wscale; /* Window scaling received from sender  */
        __u8    rcv_wscale; /* Window scaling to send to receiver   */
    __u8    nonagle;    /* Disable Nagle algorithm?             */
    __u8    keepalive_probes; /* num of allowed keep alive probes   */

/*  PAWS/RTTM data  */
        __u32   rcv_tsval;  /* Time stamp value                 */
        __u32   rcv_tsecr;  /* Time stamp echo reply            */
        __u32   ts_recent;  /* Time stamp to echo next      */
        long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */

/*  SACKs data  */
    __u16   user_mss;   /* mss requested by user in ioctl */
    __u8    dsack;      /* D-SACK is scheduled          */
    __u8    eff_sacks;  /* Size of SACK array to send with next packet */
    struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
    struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/

    __u32   window_clamp;   /* Maximal window to advertise      */
    __u32   rcv_ssthresh;   /* Current window clamp         */
    __u8    probes_out; /* unanswered 0 window probes       */
    __u8    num_sacks;  /* Number of SACK blocks        */
    __u16   advmss;     /* Advertised MSS           */

    __u8    syn_retries;    /* num of allowed syn retries */
    __u8    ecn_flags;  /* ECN status bits.         */
    __u16   prior_ssthresh; /* ssthresh saved at recovery start */
    __u32   lost_out;   /* Lost packets             */
    __u32   sacked_out; /* SACK'd packets           */
    __u32   fackets_out;    /* FACK'd packets           */
    __u32   high_seq;   /* snd_nxt at onset of congestion   */

    __u32   retrans_stamp;  /* Timestamp of the last retransmit,
                 * also used in SYN-SENT to remember stamp of
                 * the first SYN. */
    __u32   undo_marker;    /* tracking retrans started here. */
    int undo_retrans;   /* number of undoable retransmissions. */
    __u32   urg_seq;    /* Seq of received urgent pointer */
    __u16   urg_data;   /* Saved octet of OOB data and control flags */
    __u8    pending;    /* Scheduled timer event    */
    __u8    urg_mode;   /* In urgent mode       */
    __u32   snd_up;     /* Urgent pointer       */

    /* The syn_wait_lock is necessary only to avoid tcp_get_info having
     * to grab the main lock sock while browsing the listening hash
     * (otherwise it's deadlock prone).
     * This lock is acquired in read mode only from tcp_get_info() and
     * it's acquired in write mode _only_ from code that is actively
     * changing the syn_wait_queue. All readers that are holding
     * the master sock lock don't need to grab this lock in read mode
     * too as the syn_wait_queue writes are always protected from
     * the main sock lock.
     */
    rwlock_t        syn_wait_lock;
    struct tcp_listen_opt   *listen_opt;

    /* FIFO of established children */
    struct open_request *accept_queue;
    struct open_request *accept_queue_tail;

    int         write_pending;  /* A write to socket waits to start. */

    unsigned int        keepalive_time;   /* time before keep alive takes place */
    unsigned int        keepalive_intvl;  /* time interval between keep alive probes */
    int         linger2;

    unsigned long last_synq_overflow;
};




/* This is the per-socket lock.  The spinlock provides a synchronization
 * between user contexts and software interrupt processing, whereas the
 * mini-semaphore synchronizes multiple users amongst themselves.
 */
typedef struct {
    spinlock_t      slock;
    unsigned int        users;
    wait_queue_head_t   wq;
} socket_lock_t;

struct sock {
    /* Socket demultiplex comparisons on incoming packets. */
    __u32           daddr;      /* Foreign IPv4 addr            */
    __u32           rcv_saddr;  /* Bound local IPv4 addr        */
    __u16           dport;      /* Destination port         */
    unsigned short      num;        /* Local port               */
    int         bound_dev_if;   /* Bound device index if != 0       */

    /* Main hash linkage for various protocol lookup tables. */
    struct sock     *next;
    struct sock     **pprev;
    struct sock     *bind_next;
    struct sock     **bind_pprev;

    volatile unsigned char  state,      /* Connection state         */
                zapped;     /* In ax25 & ipx means not linked   */
    __u16           sport;      /* Source port              */

    unsigned short      family;     /* Address family           */
    unsigned char       reuse;      /* SO_REUSEADDR setting         */
    unsigned char       shutdown;
    atomic_t        refcnt;     /* Reference count          */

    socket_lock_t       lock;       /* Synchronizer...          */
    int         rcvbuf;     /* Size of receive buffer in bytes  */

    wait_queue_head_t   *sleep;     /* Sock wait queue          */
    struct dst_entry    *dst_cache; /* Destination cache            */
    rwlock_t        dst_lock;
    atomic_t        rmem_alloc; /* Receive queue bytes committed    */
    struct sk_buff_head receive_queue;  /* Incoming packets         */
    atomic_t        wmem_alloc; /* Transmit queue bytes committed   */
    struct sk_buff_head write_queue;    /* Packet sending queue         */
    atomic_t        omem_alloc; /* "o" is "option" or "other" */
    int         wmem_queued;    /* Persistent queue size */
    int         forward_alloc;  /* Space allocated forward. */
    __u32           saddr;      /* Sending source           */
    unsigned int        allocation; /* Allocation mode          */
    int         sndbuf;     /* Size of send buffer in bytes     */
    struct sock     *prev;

    /* Not all are volatile, but some are, so we might as well say they all are.
     * XXX Make this a flag word -DaveM
     */
    volatile char       dead,
                done,
                urginline,
                keepopen,
                linger,
                destroy,
                no_check,
                broadcast,
                bsdism;
    unsigned char       debug;
    unsigned char       rcvtstamp;
    unsigned char       use_write_queue;
    unsigned char       userlocks;
    /* Hole of 3 bytes. Try to pack. */
    int         route_caps;
    int         proc;
    unsigned long           lingertime;

    int         hashent;
    struct sock     *pair;

    /* The backlog queue is special, it is always used with
     * the per-socket spinlock held and requires low latency
     * access.  Therefore we special case it's implementation.
     */
    struct {
        struct sk_buff *head;
        struct sk_buff *tail;
    } backlog;

    rwlock_t        callback_lock;

    /* Error queue, rarely used. */
    struct sk_buff_head error_queue;

    struct proto        *prot;

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
    union {
        struct ipv6_pinfo   af_inet6;
    } net_pinfo;
#endif

    union {
        struct tcp_opt      af_tcp;
#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
        struct raw_opt      tp_raw4;
#endif
#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
        struct raw6_opt     tp_raw;
#endif /* CONFIG_IPV6 */
#if defined(CONFIG_SPX) || defined (CONFIG_SPX_MODULE)
        struct spx_opt      af_spx;
#endif /* CONFIG_SPX */

    } tp_pinfo;

    int         err, err_soft;  /* Soft holds errors that don't
                           cause failure but are the cause
                           of a persistent failure not just
                           'timed out' */
    unsigned short      ack_backlog;
    unsigned short      max_ack_backlog;
    __u32           priority;
    unsigned short      type;
    unsigned char       localroute; /* Route locally only */
    unsigned char       protocol;
//  struct ucred        peercred;
    int         rcvlowat;
    long            rcvtimeo;
    long            sndtimeo;

#ifdef CONFIG_FILTER
    /* Socket Filtering Instructions */
    struct sk_filter        *filter;
#endif /* CONFIG_FILTER */

    /* This is where all the private (optional) areas that don't
     * overlap will eventually live.
     */
    union {
        void *destruct_hook;
//      struct unix_opt af_unix;
#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
        struct inet_opt af_inet;
#endif
#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
        struct atalk_sock   af_at;
#endif
#if defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
        struct ipx_opt      af_ipx;
#endif
#if defined (CONFIG_DECNET) || defined(CONFIG_DECNET_MODULE)
        struct dn_scp           dn;
#endif
#if defined (CONFIG_PACKET) || defined(CONFIG_PACKET_MODULE)
        struct packet_opt   *af_packet;
#endif
#if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
        x25_cb          *x25;
#endif
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
        ax25_cb         *ax25;
#endif
#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
        nr_cb           *nr;
#endif
#if defined(CONFIG_ROSE) || defined(CONFIG_ROSE_MODULE)
        rose_cb         *rose;
#endif
#if defined(CONFIG_PPPOE) || defined(CONFIG_PPPOE_MODULE)
        struct pppox_opt    *pppox;
#endif
        struct netlink_opt  *af_netlink;
#if defined(CONFIG_ECONET) || defined(CONFIG_ECONET_MODULE)
        struct econet_opt   *af_econet;
#endif
#if defined(CONFIG_ATM) || defined(CONFIG_ATM_MODULE)
        struct atm_vcc      *af_atm;
#endif
#if defined(CONFIG_IRDA) || defined(CONFIG_IRDA_MODULE)
        struct irda_sock        *irda;
#endif
#if defined(CONFIG_WAN_ROUTER) || defined(CONFIG_WAN_ROUTER_MODULE)
               struct wanpipe_opt      *af_wanpipe;
#endif
    } protinfo;


    /* This part is used for the timeout functions. */
    struct timer_list   timer;      /* This is the sock cleanup timer. */
    struct timeval      stamp;

    /* Identd and reporting IO signals */
    struct socket       *socket;

    /* RPC layer private data */
    void            *user_data;

    /* Callbacks */
    void            (*state_change)(struct sock *sk);
    void            (*data_ready)(struct sock *sk,int bytes);
    void            (*write_space)(struct sock *sk);
    void            (*error_report)(struct sock *sk);

    int         (*backlog_rcv) (struct sock *sk,
                        struct sk_buff *skb);
    void                    (*destruct)(struct sock *sk);
};




#if 1 /* dst (_NET_DST_H) */

#if 0
#include <linux/config.h>
#include <net/neighbour.h>
#endif

/*
 * 0 - no debugging messages
 * 1 - rare events and bugs (default)
 * 2 - trace mode.
 */
#define RT_CACHE_DEBUG      0

#define DST_GC_MIN  (1*HZ)
#define DST_GC_INC  (5*HZ)
#define DST_GC_MAX  (120*HZ)

struct sk_buff;

struct dst_entry
{
    struct dst_entry        *next;
    atomic_t        __refcnt;   /* client references    */
    int         __use;
    struct net_device       *dev;
    int         obsolete;
    int         flags;
#define DST_HOST        1
    unsigned long       lastuse;
    unsigned long       expires;

    unsigned        mxlock;
    unsigned        pmtu;
    unsigned        window;
    unsigned        rtt;
    unsigned        rttvar;
    unsigned        ssthresh;
    unsigned        cwnd;
    unsigned        advmss;
    unsigned        reordering;

    unsigned long       rate_last;  /* rate limiting for ICMP */
    unsigned long       rate_tokens;

    int         error;

    struct neighbour    *neighbour;
    struct hh_cache     *hh;

    int         (*input)(struct sk_buff*);
    int         (*output)(struct sk_buff*);

#ifdef CONFIG_NET_CLS_ROUTE
    __u32           tclassid;
#endif

    struct  dst_ops         *ops;

    char            info[0];
};


struct dst_ops
{
    unsigned short      family;
    unsigned short      protocol;
    unsigned        gc_thresh;

    int         (*gc)(void);
    struct dst_entry *  (*check)(struct dst_entry *, __u32 cookie);
    struct dst_entry *  (*reroute)(struct dst_entry *,
                       struct sk_buff *);
    void            (*destroy)(struct dst_entry *);
    struct dst_entry *  (*negative_advice)(struct dst_entry *);
    void            (*link_failure)(struct sk_buff *);
    int         entry_size;

    atomic_t        entries;
    kmem_cache_t        *kmem_cachep;
};

#ifdef __KERNEL__

static __inline void dst_hold(struct dst_entry * dst)
{
    atomic_inc(&dst->__refcnt);
}

static __inline
struct dst_entry * dst_clone(struct dst_entry * dst)
{
    if (dst)
        atomic_inc(&dst->__refcnt);
    return dst;
}

static __inline
void dst_release(struct dst_entry * dst)
{
    if (dst)
        atomic_dec(&dst->__refcnt);
}

extern void * dst_alloc(struct dst_ops * ops);
extern void __dst_free(struct dst_entry * dst);
extern void dst_destroy(struct dst_entry * dst);

static __inline
void dst_free(struct dst_entry * dst)
{
    if (dst->obsolete > 1)
        return;
    if (!atomic_read(&dst->__refcnt)) {
        dst_destroy(dst);
        return;
    }
    __dst_free(dst);
}

static __inline void dst_confirm(struct dst_entry *dst)
{
    if (dst)
        neigh_confirm(dst->neighbour);
}

static __inline void dst_negative_advice(struct dst_entry **dst_p)
{
    struct dst_entry * dst = *dst_p;
    if (dst && dst->ops->negative_advice)
        *dst_p = dst->ops->negative_advice(dst);
}

static __inline void dst_link_failure(struct sk_buff *skb)
{
    struct dst_entry * dst = skb->dst;
    if (dst && dst->ops && dst->ops->link_failure)
        dst->ops->link_failure(skb);
}

static __inline void dst_set_expires(struct dst_entry *dst, int timeout)
{
    unsigned long expires = jiffies + timeout;

    if (expires == 0)
        expires = 1;

    if (dst->expires == 0 || (long)(dst->expires - expires) > 0)
        dst->expires = expires;
}

extern void     dst_init(void);

#endif /* dst */



#if 1
/* dummy types */


#endif

#define TCP_DEBUG 1
#define FASTRETRANS_DEBUG 1

/* Cancel timers, when they are not required. */
#undef TCP_CLEAR_TIMERS

#if 0
#include <linux/config.h>
#include <linux/tcp.h>
#include <linux/slab.h>
#include <linux/cache.h>
#include <net/checksum.h>
#include <net/sock.h>
#else
#include "linux.h"
#endif

/* 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 {
    /* These _must_ match the beginning of struct sock precisely.
     * XXX Yes I know this is gross, but I'd have to edit every single
     * XXX networking file if I created a "struct sock_header". -DaveM
     */
    __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)
{
#if 0
    return num & (TCP_LHTABLE_SIZE - 1);
#else
  return 0;
#endif
}

static __inline int tcp_sk_listen_hashfn(struct sock *sk)
{
#if 0
    return tcp_lhashfn(sk->num);
#else
  return 0;
#endif
}

#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 minimum   */

#define TCP_SYNACK_RETRIES 5    /* number of times to retry passive opening a
                 * connection: ~180sec is RFC minimum   */


#define TCP_ORPHAN_RETRIES 7    /* number of times to retry on an orphaned
                 * socket. 7 is ~50sec-16min.
                 */


#define TCP_TIMEWAIT_LEN (60*1000)
//#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 0
#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
#else
#define TCP_TW_RECYCLE_TICK (0)
#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 */

#if 0
/* 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;
#endif

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;

#ifdef ROS_STATISTICS
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)
#endif

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)
{
#if 0
    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;
    };
#endif
}

/*
 *  Reset the retransmission timer
 */
static __inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when)
{
#if 0
    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");
    };
#endif
}

/* 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)
{
#if 0
    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;
#else
  return 0;
#endif
}

/* 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)
{
#if 0
    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;
#endif
}

static __inline void __tcp_fast_path_on(struct tcp_opt *tp, u32 snd_wnd)
{
#if 0
    tp->pred_flags = htonl((tp->tcp_header_len << 26) |
                   ntohl(TCP_FLAG_ACK) |
                   snd_wnd);
#endif
}

static __inline void tcp_fast_path_on(struct tcp_opt *tp)
{
#if 0
    __tcp_fast_path_on(tp, tp->snd_wnd>>tp->snd_wscale);
#endif
}

static __inline void tcp_fast_path_check(struct sock *sk, struct tcp_opt *tp)
{
#if 0
    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);
#endif
}

/* 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)
{
#if 0
    s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;

    if (win < 0)
        win = 0;
    return (u32) win;
#else
  return 0;
#endif
}

/* 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 decidedly
 * 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 {
#if 0
        struct inet_skb_parm    h4;
#endif
#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)
{
#if 0
    return sk->wmem_queued/2;
#else
return 0;
#endif
}

static __inline int tcp_wspace(struct sock *sk)
{
#if 0
    return sk->sndbuf - sk->wmem_queued;
#else
return 0;
#endif
}


/* 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)
{
#if 0
    return tp->packets_out - tp->left_out + tp->retrans_out;
#else
  return 0;
#endif
}

/* 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)
{
#if 0
    return max(tp->snd_cwnd >> 1U, 2U);
#else
  return 0;
#endif
}

/* 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 0
    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)));
#else
  return 0;
#endif
}

static __inline void tcp_sync_left_out(struct tcp_opt *tp)
{
#if 0
    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;
#endif
}

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 0
    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);
    }
#endif
}

/* Set slow start threshold and cwnd not falling to slow start */
static __inline void __tcp_enter_cwr(struct tcp_opt *tp)
{
#if 0
    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);
#endif
}

static __inline void tcp_enter_cwr(struct tcp_opt *tp)
{
#if 0
    tp->prior_ssthresh = 0;
    if (tp->ca_state < TCP_CA_CWR) {
        __tcp_enter_cwr(tp);
        tp->ca_state = TCP_CA_CWR;
    }
#endif
}

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)
{
#if 0
    return after(tp->snd_sml,tp->snd_una) &&
        !after(tp->snd_sml, tp->snd_nxt);
#else
  return 0;
#endif
}

static __inline void tcp_minshall_update(struct tcp_opt *tp, int mss, struct sk_buff *skb)
{
#if 0
    if (skb->len < mss)
        tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
#endif
}

/* 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)
{
#if 0
    return (skb->len < mss_now &&
        !(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
        (nonagle == 2 ||
         (!nonagle &&
          tp->packets_out &&
          tcp_minshall_check(tp))));
#else
  return 0;
#endif
}

/* 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)
{
#if 0
    /*  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));
#else
  return 0;
#endif
}

static __inline void tcp_check_probe_timer(struct sock *sk, struct tcp_opt *tp)
{
#if 0
    if (!tp->packets_out && !tp->pending)
        tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto);
#endif
}

static __inline int tcp_skb_is_last(struct sock *sk, struct sk_buff *skb)
{
#if 0
    return (skb->next == (struct sk_buff*)&sk->write_queue);
#else
  return 0;
#endif
}

/* 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)
{
#if 0
    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);
#endif
}

static __inline void tcp_push_pending_frames(struct sock *sk,
                           struct tcp_opt *tp)
{
#if 0
    __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk), tp->nonagle);
#endif
}

static __inline int tcp_may_send_now(struct sock *sk, struct tcp_opt *tp)
{
#if 0
    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));
#else
  return 0;
#endif
}

static __inline void tcp_init_wl(struct tcp_opt *tp, u32 ack, u32 seq)
{
#if 0
    tp->snd_wl1 = seq;
#endif
}

static __inline void tcp_update_wl(struct tcp_opt *tp, u32 ack, u32 seq)
{
#if 0
    tp->snd_wl1 = seq;
#endif
}

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)
{
#if 0
    return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
#else
  return 0;
#endif
}

static __inline int __tcp_checksum_complete(struct sk_buff *skb)
{
#if 0
    return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
#else
  return 0;
#endif
}

static __inline int tcp_checksum_complete(struct sk_buff *skb)
{
#if 0
    return skb->ip_summed != CHECKSUM_UNNECESSARY &&
        __tcp_checksum_complete(skb);
#else
  return 0;
#endif
}

/* Prequeue for VJ style copy to user, combined with checksumming. */

static __inline void tcp_prequeue_init(struct tcp_opt *tp)
{
#if 0
    tp->ucopy.task = NULL;
    tp->ucopy.len = 0;
    tp->ucopy.memory = 0;
    skb_queue_head_init(&tp->ucopy.prequeue);
#endif
}

/* 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)
{
#if 0
    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;
#else
  return 0;
#endif
}


#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)
{
#if 0
    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
#endif
}

static __inline void tcp_done(struct sock *sk)
{
#if 0
    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);
#endif
}

static __inline void tcp_sack_reset(struct tcp_opt *tp)
{
#if 0
    tp->dsack = 0;
    tp->eff_sacks = 0;
    tp->num_sacks = 0;
#endif
}

static __inline void tcp_build_and_update_options(__u32 *ptr, struct tcp_opt *tp, __u32 tstamp)
{
#if 0
    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--;
        }
    }
#endif
}

/* 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)
{
#if 0
    /* 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));
#endif
}

/* 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)
{
#if 0
    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);
#endif
}

static __inline int tcp_win_from_space(int space)
{
#if 0
    return sysctl_tcp_adv_win_scale<=0 ?
        (space>>(-sysctl_tcp_adv_win_scale)) :
        space - (space>>sysctl_tcp_adv_win_scale);
#else
  return 0;
#endif
}

/* Note: caller must be prepared to deal with negative returns */
static __inline int tcp_space(struct sock *sk)
{
#if 0
    return tcp_win_from_space(sk->rcvbuf - atomic_read(&sk->rmem_alloc));
#else
  return 0;
#endif
}

static __inline int tcp_full_space( struct sock *sk)
{
#if 0
    return tcp_win_from_space(sk->rcvbuf);
#else
  return 0;
#endif
}

static __inline void tcp_acceptq_removed(struct sock *sk)
{
#if 0
    sk->ack_backlog--;
#endif
}

static __inline void tcp_acceptq_added(struct sock *sk)
{
#if 0
    sk->ack_backlog++;
#endif
}

static __inline int tcp_acceptq_is_full(struct sock *sk)
{
#if 0
    return sk->ack_backlog > sk->max_ack_backlog;
#else
  return 0;
#endif
}

static __inline void tcp_acceptq_queue(struct sock *sk, struct open_request *req,
                     struct sock *child)
{
#if 0
    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;
#endif
}

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)
{
#if 0
    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--;
#endif
}

static __inline void tcp_synq_added(struct sock *sk)
{
#if 0
    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++;
#endif
}

static __inline int tcp_synq_len(struct sock *sk)
{
#if 0
    return sk->tp_pinfo.af_tcp.listen_opt->qlen;
#else
  return 0;
#endif
}

static __inline int tcp_synq_young(struct sock *sk)
{
#if 0
    return sk->tp_pinfo.af_tcp.listen_opt->qlen_young;
#else
  return 0;
#endif
}

static __inline int tcp_synq_is_full(struct sock *sk)
{
#if 0
    return tcp_synq_len(sk)>>sk->tp_pinfo.af_tcp.listen_opt->max_qlen_log;
#else
  return 0;
#endif
}

static __inline void tcp_synq_unlink(struct tcp_opt *tp, struct open_request *req,
                       struct open_request **prev)
{
#if 0
    write_lock(&tp->syn_wait_lock);
    *prev = req->dl_next;
    write_unlock(&tp->syn_wait_lock);
#endif
}

static __inline void tcp_synq_drop(struct sock *sk, struct open_request *req,
                     struct open_request **prev)
{
#if 0
    tcp_synq_unlink(&sk->tp_pinfo.af_tcp, req, prev);
    tcp_synq_removed(sk, req);
    tcp_openreq_free(req);
#endif
}

static __inline void tcp_openreq_init(struct open_request *req,
                    struct tcp_opt *tp,
                    struct sk_buff *skb)
{
#if 0
    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;
#endif
}

#define TCP_MEM_QUANTUM ((int)PAGE_SIZE)

static __inline void tcp_free_skb(struct sock *sk, struct sk_buff *skb)
{
#if 0
    sk->tp_pinfo.af_tcp.queue_shrunk = 1;
    sk->wmem_queued -= skb->truesize;
    sk->forward_alloc += skb->truesize;
    __kfree_skb(skb);
#endif
}

static __inline void tcp_charge_skb(struct sock *sk, struct sk_buff *skb)
{
#if 0
    sk->wmem_queued += skb->truesize;
    sk->forward_alloc -= skb->truesize;
#endif
}

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 0
    if (sk->forward_alloc >= TCP_MEM_QUANTUM)
        __tcp_mem_reclaim(sk);
#endif
}

static __inline void tcp_enter_memory_pressure(void)
{
#if 0
    if (!tcp_memory_pressure) {
        NET_INC_STATS(TCPMemoryPressures);
        tcp_memory_pressure = 1;
    }
#endif
}

static __inline void tcp_moderate_sndbuf(struct sock *sk)
{
#if 0
    if (!(sk->userlocks&SOCK_SNDBUF_LOCK)) {
        sk->sndbuf = min(sk->sndbuf, sk->wmem_queued/2);
        sk->sndbuf = max(sk->sndbuf, SOCK_MIN_SNDBUF);
    }
#endif
}

static __inline struct sk_buff *tcp_alloc_pskb(struct sock *sk, int size, int mem, int gfp)
{
#if 0
    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;
#else
  return NULL;
#endif
}

static __inline struct sk_buff *tcp_alloc_skb(struct sock *sk, int size, int gfp)
{
#if 0
    return tcp_alloc_pskb(sk, size, 0, gfp);
#else
  return NULL;
#endif
}

static __inline struct page * tcp_alloc_page(struct sock *sk)
{
#if 0
    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;
#else
  return NULL;
#endif
}

static __inline void tcp_writequeue_purge(struct sock *sk)
{
#if 0
    struct sk_buff *skb;

    while ((skb = __skb_dequeue(&sk->write_queue)) != NULL)
        tcp_free_skb(sk, skb);
    tcp_mem_reclaim(sk);
#endif
}

extern void tcp_rfree(struct sk_buff *skb);

static __inline void tcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
#if 0
    skb->sk = sk;
    skb->destructor = tcp_rfree;
    atomic_add(skb->truesize, &sk->rmem_alloc);
    sk->forward_alloc -= skb->truesize;
#endif
}

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)
{
#if 0
    /* read_lock synchronizes to candidates to writers */
    read_lock(&tcp_lhash_lock);
    atomic_inc(&tcp_lhash_users);
    read_unlock(&tcp_lhash_lock);
#endif
}

static __inline void tcp_listen_unlock(void)
{
#if 0
    if (atomic_dec_and_test(&tcp_lhash_users))
        wake_up(&tcp_lhash_wait);
#endif
}

static __inline int keepalive_intvl_when(struct tcp_opt *tp)
{
#if 0
    return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
#else
  return 0;
#endif
}

static __inline int keepalive_time_when(struct tcp_opt *tp)
{
#if 0
    return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
#else
  return 0;
#endif
}

static __inline int tcp_fin_time(struct tcp_opt *tp)
{
#if 0
    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;
#else
  return 0;
#endif
}

static __inline int tcp_paws_check(struct tcp_opt *tp, int rst)
{
#if 0
    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;
#else
  return 0;
#endif
}

#define TCP_CHECK_TIMER(sk) do { } while (0)

#endif /* __TCPCORE_H */


//
#endif