sock.c

LINUX 1.0 内核c源代码,是一份精简的linux内核源代码

  /* Check this error. */
  if (len < sizeof(sin)) return(-EINVAL);

  sin.sin_family = AF_INET;
  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }
  if (peer) {
	if (!tcp_connected(sk->state)) return(-ENOTCONN);
	sin.sin_port = sk->dummy_th.dest;
	sin.sin_addr.s_addr = sk->daddr;
  } else {
	sin.sin_port = sk->dummy_th.source;
	if (sk->saddr == 0) sin.sin_addr.s_addr = my_addr();
	  else sin.sin_addr.s_addr = sk->saddr;
  }
  len = sizeof(sin);
/*  verify_area(VERIFY_WRITE, uaddr, len); NOW DONE ABOVE */
  memcpy_tofs(uaddr, &sin, sizeof(sin));
/*  verify_area(VERIFY_WRITE, uaddr_len, sizeof(len)); NOW DONE ABOVE */
  put_fs_long(len, uaddr_len);
  return(0);
}


static int
inet_read(struct socket *sock, char *ubuf, int size, int noblock)
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }
  return(sk->prot->read(sk, (unsigned char *) ubuf, size, noblock,0));
}


static int
inet_recv(struct socket *sock, void *ubuf, int size, int noblock,
	  unsigned flags)
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }
  return(sk->prot->read(sk, (unsigned char *) ubuf, size, noblock, flags));
}


static int
inet_write(struct socket *sock, char *ubuf, int size, int noblock)
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }
  if (sk->shutdown & SEND_SHUTDOWN) {
	send_sig(SIGPIPE, current, 1);
	return(-EPIPE);
  }

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }

  return(sk->prot->write(sk, (unsigned char *) ubuf, size, noblock, 0));
}


static int
inet_send(struct socket *sock, void *ubuf, int size, int noblock, 
	       unsigned flags)
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }
  if (sk->shutdown & SEND_SHUTDOWN) {
	send_sig(SIGPIPE, current, 1);
	return(-EPIPE);
  }

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }

  return(sk->prot->write(sk, (unsigned char *) ubuf, size, noblock, flags));
}


static int
inet_sendto(struct socket *sock, void *ubuf, int size, int noblock, 
	    unsigned flags, struct sockaddr *sin, int addr_len)
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }
  if (sk->shutdown & SEND_SHUTDOWN) {
	send_sig(SIGPIPE, current, 1);
	return(-EPIPE);
  }

  if (sk->prot->sendto == NULL) return(-EOPNOTSUPP);

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }

  return(sk->prot->sendto(sk, (unsigned char *) ubuf, size, noblock, flags, 
			   (struct sockaddr_in *)sin, addr_len));
}


static int
inet_recvfrom(struct socket *sock, void *ubuf, int size, int noblock, 
		   unsigned flags, struct sockaddr *sin, int *addr_len )
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }

  if (sk->prot->recvfrom == NULL) return(-EOPNOTSUPP);

  /* We may need to bind the socket. */
  if (sk->num == 0) {
	sk->num = get_new_socknum(sk->prot, 0);
	if (sk->num == 0) return(-EAGAIN);
	put_sock(sk->num, sk);
	sk->dummy_th.source = ntohs(sk->num);
  }

  return(sk->prot->recvfrom(sk, (unsigned char *) ubuf, size, noblock, flags,
			     (struct sockaddr_in*)sin, addr_len));
}


static int
inet_shutdown(struct socket *sock, int how)
{
  struct sock *sk;

  /*
   * This should really check to make sure
   * the socket is a TCP socket.
   */
  how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
		       1->2 bit 2 snds.
		       2->3 */
  if (how & ~SHUTDOWN_MASK) return(-EINVAL);
  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }
  if (sock->state == SS_CONNECTING && sk->state == TCP_ESTABLISHED)
						sock->state = SS_CONNECTED;

  if (!tcp_connected(sk->state)) return(-ENOTCONN);
  sk->shutdown |= how;
  if (sk->prot->shutdown) sk->prot->shutdown(sk, how);
  return(0);
}


static int
inet_select(struct socket *sock, int sel_type, select_table *wait )
{
  struct sock *sk;

  sk = (struct sock *) sock->data;
  if (sk == NULL) {
	printk("Warning: sock->data = NULL: %d\n" ,__LINE__);
	return(0);
  }

  if (sk->prot->select == NULL) {
	DPRINTF((DBG_INET, "select on non-selectable socket.\n"));
	return(0);
  }
  return(sk->prot->select(sk, sel_type, wait));
}


static int
inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
  struct sock *sk;
  int err;

  DPRINTF((DBG_INET, "INET: in inet_ioctl\n"));
  sk = NULL;
  if (sock && (sk = (struct sock *) sock->data) == NULL) {
	printk("AF_INET: Warning: sock->data = NULL: %d\n" , __LINE__);
	return(0);
  }

  switch(cmd) {
	case FIOSETOWN:
	case SIOCSPGRP:
		err=verify_area(VERIFY_READ,(int *)arg,sizeof(long));
		if(err)
			return err;
		if (sk)
			sk->proc = get_fs_long((int *) arg);
		return(0);
	case FIOGETOWN:
	case SIOCGPGRP:
		if (sk) {
			err=verify_area(VERIFY_WRITE,(void *) arg, sizeof(long));
			if(err)
				return err;
			put_fs_long(sk->proc,(int *)arg);
		}
		return(0);
#if 0	/* FIXME: */
	case SIOCATMARK:
		printk("AF_INET: ioctl(SIOCATMARK, 0x%08X)\n",(void *) arg);
		return(-EINVAL);
#endif

	case DDIOCSDBG:
		return(dbg_ioctl((void *) arg, DBG_INET));

	case SIOCADDRT: case SIOCADDRTOLD:
	case SIOCDELRT: case SIOCDELRTOLD:
		return(rt_ioctl(cmd,(void *) arg));

	case SIOCDARP:
	case SIOCGARP:
	case SIOCSARP:
		return(arp_ioctl(cmd,(void *) arg));

	case IP_SET_DEV:
	case SIOCGIFCONF:
	case SIOCGIFFLAGS:
	case SIOCSIFFLAGS:
	case SIOCGIFADDR:
	case SIOCSIFADDR:
	case SIOCGIFDSTADDR:
	case SIOCSIFDSTADDR:
	case SIOCGIFBRDADDR:
	case SIOCSIFBRDADDR:
	case SIOCGIFNETMASK:
	case SIOCSIFNETMASK:
	case SIOCGIFMETRIC:
	case SIOCSIFMETRIC:
	case SIOCGIFMEM:
	case SIOCSIFMEM:
	case SIOCGIFMTU:
	case SIOCSIFMTU:
	case SIOCSIFLINK:
	case SIOCGIFHWADDR:
		return(dev_ioctl(cmd,(void *) arg));

	default:
		if (!sk || !sk->prot->ioctl) return(-EINVAL);
		return(sk->prot->ioctl(sk, cmd, arg));
  }
  /*NOTREACHED*/
  return(0);
}


struct sk_buff *
sock_wmalloc(struct sock *sk, unsigned long size, int force,
	     int priority)
{
  if (sk) {
	if (sk->wmem_alloc + size < sk->sndbuf || force) {
		struct sk_buff * c = alloc_skb(size, priority);
		if (c) {
			cli();
			sk->wmem_alloc+= size;
			sti();
		}
		return c;
	}
	DPRINTF((DBG_INET, "sock_wmalloc(%X,%d,%d,%d) returning NULL\n",
						sk, size, force, priority));
	return(NULL);
  }
  return(alloc_skb(size, priority));
}


struct sk_buff *
sock_rmalloc(struct sock *sk, unsigned long size, int force, int priority)
{
  if (sk) {
	if (sk->rmem_alloc + size < sk->rcvbuf || force) {
		struct sk_buff *c = alloc_skb(size, priority);
		if (c) {
			cli();
			sk->rmem_alloc += size;
			sti();
		}
		return(c);
	}
	DPRINTF((DBG_INET, "sock_rmalloc(%X,%d,%d,%d) returning NULL\n",
						sk,size,force, priority));
	return(NULL);
  }
  return(alloc_skb(size, priority));
}


unsigned long
sock_rspace(struct sock *sk)
{
  int amt;

  if (sk != NULL) {
	if (sk->rmem_alloc >= sk->rcvbuf-2*MIN_WINDOW) return(0);
	amt = min((sk->rcvbuf-sk->rmem_alloc)/2-MIN_WINDOW, MAX_WINDOW);
	if (amt < 0) return(0);
	return(amt);
  }
  return(0);
}


unsigned long
sock_wspace(struct sock *sk)
{
  if (sk != NULL) {
	if (sk->shutdown & SEND_SHUTDOWN) return(0);
	if (sk->wmem_alloc >= sk->sndbuf) return(0);
	return(sk->sndbuf-sk->wmem_alloc );
  }
  return(0);
}


void
sock_wfree(struct sock *sk, void *mem, unsigned long size)
{
  DPRINTF((DBG_INET, "sock_wfree(sk=%X, mem=%X, size=%d)\n", sk, mem, size));

  IS_SKB(mem);
  kfree_skbmem(mem, size);
  if (sk) {
	sk->wmem_alloc -= size;

	/* In case it might be waiting for more memory. */
	if (!sk->dead) sk->write_space(sk);
	if (sk->destroy && sk->wmem_alloc == 0 && sk->rmem_alloc == 0) {
		DPRINTF((DBG_INET,
			"recovered lost memory, sock = %X\n", sk));
	}
	return;
  }
}


void
sock_rfree(struct sock *sk, void *mem, unsigned long size)
{
  DPRINTF((DBG_INET, "sock_rfree(sk=%X, mem=%X, size=%d)\n", sk, mem, size));
  IS_SKB(mem);
  kfree_skbmem(mem, size);
  if (sk) {
	sk->rmem_alloc -= size;
	if (sk->destroy && sk->wmem_alloc == 0 && sk->rmem_alloc == 0) {
		DPRINTF((DBG_INET,
			"recovered lot memory, sock = %X\n", sk));
	}
  }
}


/*
 * This routine must find a socket given a TCP or UDP header.
 * Everyhting is assumed to be in net order.
 */
struct sock *get_sock(struct proto *prot, unsigned short num,
				unsigned long raddr,
				unsigned short rnum, unsigned long laddr)
{
  struct sock *s;
  unsigned short hnum;

  hnum = ntohs(num);
  DPRINTF((DBG_INET, "get_sock(prot=%X, num=%d, raddr=%X, rnum=%d, laddr=%X)\n",
	  prot, num, raddr, rnum, laddr));

  /*
   * SOCK_ARRAY_SIZE must be a power of two.  This will work better
   * than a prime unless 3 or more sockets end up using the same
   * array entry.  This should not be a problem because most
   * well known sockets don't overlap that much, and for
   * the other ones, we can just be careful about picking our
   * socket number when we choose an arbitrary one.
   */
  for(s = prot->sock_array[hnum & (SOCK_ARRAY_SIZE - 1)];
      s != NULL; s = s->next) 
  {
	if (s->num != hnum) 
		continue;
	if(s->dead && (s->state == TCP_CLOSE))
		continue;
	if(prot == &udp_prot)
		return s;
	if(ip_addr_match(s->daddr,raddr)==0)
		continue;
	if (s->dummy_th.dest != rnum && s->dummy_th.dest != 0) 
		continue;
	if(ip_addr_match(s->saddr,laddr) == 0)
		continue;
	return(s);
  }
  return(NULL);
}


void release_sock(struct sock *sk)
{
  if (!sk) {
	printk("sock.c: release_sock sk == NULL\n");
	return;
  }
  if (!sk->prot) {
/*	printk("sock.c: release_sock sk->prot == NULL\n"); */
	return;
  }

  if (sk->blog) return;

  /* See if we have any packets built up. */
  cli();
  sk->inuse = 1;
  while(sk->back_log != NULL) {
	struct sk_buff *skb;

	sk->blog = 1;
	skb =(struct sk_buff *)sk->back_log;
	DPRINTF((DBG_INET, "release_sock: skb = %X:\n", skb));
	if (skb->next != skb) {
		sk->back_log = skb->next;
		skb->prev->next = skb->next;
		skb->next->prev = skb->prev;
	} else {
		sk->back_log = NULL;
	}
	sti();
	DPRINTF((DBG_INET, "sk->back_log = %X\n", sk->back_log));
	if (sk->prot->rcv) sk->prot->rcv(skb, skb->dev, sk->opt,
					 skb->saddr, skb->len, skb->daddr, 1,

	/* Only used for/by raw sockets. */
	(struct inet_protocol *)sk->pair); 
	cli();
  }
  sk->blog = 0;
  sk->inuse = 0;
  sti();
  if (sk->dead && sk->state == TCP_CLOSE) {
	/* Should be about 2 rtt's */
	reset_timer(sk, TIME_DONE, min(sk->rtt * 2, TCP_DONE_TIME));
  }
}


static int
inet_fioctl(struct inode *inode, struct file *file,
	 unsigned int cmd, unsigned long arg)
{
  int minor, ret;

  /* Extract the minor number on which we work. */
  minor = MINOR(inode->i_rdev);
  if (minor != 0) return(-ENODEV);

  /* Now dispatch on the minor device. */
  switch(minor) {
	case 0:		/* INET */
		ret = inet_ioctl(NULL, cmd, arg);
		break;
	case 1:		/* IP */
		ret = ip_ioctl(NULL, cmd, arg);
		break;
	case 2:		/* ICMP */
		ret = icmp_ioctl(NULL, cmd, arg);
		break;
	case 3:		/* TCP */
		ret = tcp_ioctl(NULL, cmd, arg);
		break;
	case 4:		/* UDP */
		ret = udp_ioctl(NULL, cmd, arg);
		break;
	default:
		ret = -ENODEV;
  }

  return(ret);
}




static struct file_operations inet_fops = {
  NULL,		/* LSEEK	*/
  NULL,		/* READ		*/
  NULL,		/* WRITE	*/
  NULL,		/* READDIR	*/
  NULL,		/* SELECT	*/
  inet_fioctl,	/* IOCTL	*/
  NULL,		/* MMAP		*/
  NULL,		/* OPEN		*/
  NULL		/* CLOSE	*/
};


static struct proto_ops inet_proto_ops = {
  AF_INET,

  inet_create,
  inet_dup,
  inet_release,
  inet_bind,
  inet_connect,
  inet_socketpair,
  inet_accept,
  inet_getname, 
  inet_read,
  inet_write,
  inet_select,
  inet_ioctl,
  inet_listen,
  inet_send,
  inet_recv,
  inet_sendto,
  inet_recvfrom,
  inet_shutdown,
  inet_setsockopt,
  inet_getsockopt,
  inet_fcntl,
};

extern unsigned long seq_offset;

/* Called by ddi.c on kernel startup.  */
void inet_proto_init(struct ddi_proto *pro)
{
  struct inet_protocol *p;
  int i;

  printk("Swansea University Computer Society Net2Debugged [1.30]\n");
  /* Set up our UNIX VFS major device. */
  if (register_chrdev(AF_INET_MAJOR, "af_inet", &inet_fops) < 0) {
	printk("%s: cannot register major device %d!\n",
					pro->name, AF_INET_MAJOR);
	return;
  }

  /* Tell SOCKET that we are alive... */
  (void) sock_register(inet_proto_ops.family, &inet_proto_ops);

  seq_offset = CURRENT_TIME*250;

  /* Add all the protocols. */
  for(i = 0; i < SOCK_ARRAY_SIZE; i++) {
	tcp_prot.sock_array[i] = NULL;
	udp_prot.sock_array[i] = NULL;
	raw_prot.sock_array[i] = NULL;
  }
  printk("IP Protocols: ");
  for(p = inet_protocol_base; p != NULL;) {
	struct inet_protocol *tmp;

	tmp = (struct inet_protocol *) p->next;
	inet_add_protocol(p);
	printk("%s%s",p->name,tmp?", ":"\n");
	p = tmp;
  }

  /* Initialize the DEV module. */
  dev_init();

  /* Initialize the "Buffer Head" pointers. */
  bh_base[INET_BH].routine = inet_bh;
}