tcp.c

minix3的源代码

	newconf.nwtc_flags= ((unsigned long)new_di_flags
		<< 16) | new_en_flags;
	all_flags= new_en_flags | new_di_flags;

	/* check the access modes */
	if ((all_flags & NWTC_LOCPORT_MASK) != NWTC_LP_UNSET)
	{
		for (i=0, fd_ptr= tcp_fd_table; i<TCP_FD_NR; i++, fd_ptr++)
		{
			if (fd_ptr == tcp_fd)
				continue;
			if (!(fd_ptr->tf_flags & TFF_INUSE))
				continue;
			if (fd_ptr->tf_port != tcp_fd->tf_port)
				continue;
			flags= fd_ptr->tf_tcpconf.nwtc_flags;
			if ((flags & NWTC_LOCPORT_MASK) == NWTC_LP_UNSET)
				continue;
			if (fd_ptr->tf_tcpconf.nwtc_locport !=
				newconf.nwtc_locport)
				continue;
			if ((flags & NWTC_ACC_MASK) != (all_flags  &
				NWTC_ACC_MASK) ||
				(all_flags & NWTC_ACC_MASK) == NWTC_EXCL)
			{
				tcp_fd->tf_flags &= ~TFF_IOCTL_IP;
				reply_thr_get(tcp_fd, EADDRINUSE, TRUE);
				bf_afree(data);
				return NW_OK;
			}
		}
	}
				
	tcp_fd->tf_tcpconf= newconf;

	if ((all_flags & NWTC_ACC_MASK) &&
		((all_flags & NWTC_LOCPORT_MASK) == NWTC_LP_SET ||
		(all_flags & NWTC_LOCPORT_MASK) == NWTC_LP_SEL) &&
		(all_flags & NWTC_REMADDR_MASK) &&
		(all_flags & NWTC_REMPORT_MASK))
		tcp_fd->tf_flags |= TFF_CONF_SET;
	else
	{
		tcp_fd->tf_flags &= ~TFF_CONF_SET;
	}
	bf_afree(data);
	tcp_fd->tf_flags &= ~TFF_IOCTL_IP;
	reply_thr_get(tcp_fd, NW_OK, TRUE);
	return NW_OK;
}


/*
tcp_setopt
*/

PRIVATE int tcp_setopt(tcp_fd)
tcp_fd_t *tcp_fd;
{
	nwio_tcpopt_t *tcpopt;
	nwio_tcpopt_t oldopt, newopt;
	acc_t *data;
	unsigned int new_en_flags, new_di_flags,
		old_en_flags, old_di_flags;

	data= (*tcp_fd->tf_get_userdata) (tcp_fd->tf_srfd, 0,
		sizeof(nwio_tcpopt_t), TRUE);

	if (!data)
		return EFAULT;

	data= bf_packIffLess(data, sizeof(nwio_tcpopt_t));
assert (data->acc_length == sizeof(nwio_tcpopt_t));

	tcpopt= (nwio_tcpopt_t *)ptr2acc_data(data);
	oldopt= tcp_fd->tf_tcpopt;
	newopt= *tcpopt;

	old_en_flags= oldopt.nwto_flags & 0xffff;
	old_di_flags= (oldopt.nwto_flags >> 16) & 0xffff;
	new_en_flags= newopt.nwto_flags & 0xffff;
	new_di_flags= (newopt.nwto_flags >> 16) & 0xffff;
	if (new_en_flags & new_di_flags)
	{
		tcp_fd->tf_flags &= ~TFF_IOCTL_IP;
		reply_thr_get(tcp_fd, EBADMODE, TRUE);
		return NW_OK;
	}

	/* NWTO_SND_URG_MASK */
	if (!((new_en_flags | new_di_flags) & NWTO_SND_URG_MASK))
	{
		new_en_flags |= (old_en_flags & NWTO_SND_URG_MASK);
		new_di_flags |= (old_di_flags & NWTO_SND_URG_MASK);
	}

	/* NWTO_RCV_URG_MASK */
	if (!((new_en_flags | new_di_flags) & NWTO_RCV_URG_MASK))
	{
		new_en_flags |= (old_en_flags & NWTO_RCV_URG_MASK);
		new_di_flags |= (old_di_flags & NWTO_RCV_URG_MASK);
	}

	/* NWTO_BSD_URG_MASK */
	if (!((new_en_flags | new_di_flags) & NWTO_BSD_URG_MASK))
	{
		new_en_flags |= (old_en_flags & NWTO_BSD_URG_MASK);
		new_di_flags |= (old_di_flags & NWTO_BSD_URG_MASK);
	}
	else
	{
		if (tcp_fd->tf_conn == NULL)
		{
			bf_afree(data);
			tcp_fd->tf_flags &= ~TFF_IOCTL_IP;
			reply_thr_get(tcp_fd, EINVAL, TRUE);
			return NW_OK;
		}
	}

	/* NWTO_DEL_RST_MASK */
	if (!((new_en_flags | new_di_flags) & NWTO_DEL_RST_MASK))
	{
		new_en_flags |= (old_en_flags & NWTO_DEL_RST_MASK);
		new_di_flags |= (old_di_flags & NWTO_DEL_RST_MASK);
	}

	/* NWTO_BULK_MASK */
	if (!((new_en_flags | new_di_flags) & NWTO_BULK_MASK))
	{
		new_en_flags |= (old_en_flags & NWTO_BULK_MASK);
		new_di_flags |= (old_di_flags & NWTO_BULK_MASK);
	}

	newopt.nwto_flags= ((unsigned long)new_di_flags << 16) |
		new_en_flags;
	tcp_fd->tf_tcpopt= newopt;
	if (newopt.nwto_flags & NWTO_SND_URG)
		tcp_fd->tf_flags |= TFF_WR_URG;
	else
		tcp_fd->tf_flags &= ~TFF_WR_URG;

	if (newopt.nwto_flags & NWTO_RCV_URG)
		tcp_fd->tf_flags |= TFF_RECV_URG;
	else
		tcp_fd->tf_flags &= ~TFF_RECV_URG;

	if (tcp_fd->tf_conn)
	{
		if (newopt.nwto_flags & NWTO_BSD_URG)
			tcp_fd->tf_conn->tc_flags |= TCF_BSD_URG;
		else
			tcp_fd->tf_conn->tc_flags &= ~TCF_BSD_URG;
	}

	if (newopt.nwto_flags & NWTO_DEL_RST)
		tcp_fd->tf_flags |= TFF_DEL_RST;
	else
		tcp_fd->tf_flags &= ~TFF_DEL_RST;

	if (newopt.nwto_flags & NWTO_BULK)
		tcp_fd->tf_flags &= ~TFF_PUSH_DATA;
	else
		tcp_fd->tf_flags |= TFF_PUSH_DATA;

	bf_afree(data);
	tcp_fd->tf_flags &= ~TFF_IOCTL_IP;
	reply_thr_get(tcp_fd, NW_OK, TRUE);
	return NW_OK;
}


PRIVATE tcpport_t find_unused_port(fd)
int fd;
{
	tcpport_t port, nw_port;

	for (port= 0x8000+fd; port < 0xffff-TCP_FD_NR; port+= TCP_FD_NR)
	{
		nw_port= htons(port);
		if (is_unused_port(nw_port))
			return nw_port;
	}
	for (port= 0x8000; port < 0xffff; port++)
	{
		nw_port= htons(port);
		if (is_unused_port(nw_port))
			return nw_port;
	}
	ip_panic(( "unable to find unused port (shouldn't occur)" ));
	return 0;
}

PRIVATE int is_unused_port(port)
tcpport_t port;
{
	int i;
	tcp_fd_t *tcp_fd;
	tcp_conn_t *tcp_conn;

	for (i= 0, tcp_fd= tcp_fd_table; i<TCP_FD_NR; i++,
		tcp_fd++)
	{
		if (!(tcp_fd->tf_flags & TFF_CONF_SET))
			continue;
		if (tcp_fd->tf_tcpconf.nwtc_locport == port)
			return FALSE;
	}
	for (i= tcp_conf_nr, tcp_conn= tcp_conn_table+i;
		i<TCP_CONN_NR; i++, tcp_conn++)
		/* the first tcp_conf_nr ports are special */
	{
		if (!(tcp_conn->tc_flags & TCF_INUSE))
			continue;
		if (tcp_conn->tc_locport == port)
			return FALSE;
	}
	return TRUE;
}

PRIVATE int reply_thr_put(tcp_fd, reply, for_ioctl)
tcp_fd_t *tcp_fd;
int reply;
int for_ioctl;
{
	assert (tcp_fd);

	return (*tcp_fd->tf_put_userdata)(tcp_fd->tf_srfd, reply,
		(acc_t *)0, for_ioctl);
}

PRIVATE void reply_thr_get(tcp_fd, reply, for_ioctl)
tcp_fd_t *tcp_fd;
int reply;
int for_ioctl;
{
	acc_t *result;
	result= (*tcp_fd->tf_get_userdata)(tcp_fd->tf_srfd, reply,
		(size_t)0, for_ioctl);
	assert (!result);
}

PUBLIC int tcp_su4listen(tcp_fd, tcp_conn, do_listenq)
tcp_fd_t *tcp_fd;
tcp_conn_t *tcp_conn;
int do_listenq;
{
	tcp_conn->tc_locport= tcp_fd->tf_tcpconf.nwtc_locport;
	tcp_conn->tc_locaddr= tcp_fd->tf_port->tp_ipaddr;
	if (tcp_fd->tf_tcpconf.nwtc_flags & NWTC_SET_RP)
		tcp_conn->tc_remport= tcp_fd->tf_tcpconf.nwtc_remport;
	else
		tcp_conn->tc_remport= 0;
	if (tcp_fd->tf_tcpconf.nwtc_flags & NWTC_SET_RA)
		tcp_conn->tc_remaddr= tcp_fd->tf_tcpconf.nwtc_remaddr;
	else
		tcp_conn->tc_remaddr= 0;

	tcp_setup_conn(tcp_fd->tf_port, tcp_conn);
	tcp_conn->tc_fd= tcp_fd;
	tcp_conn->tc_connInprogress= 1;
	tcp_conn->tc_orglisten= TRUE;
	tcp_conn->tc_state= TCS_LISTEN;
	tcp_conn->tc_rt_dead= TCP_DEF_RT_MAX_LISTEN;
	if (do_listenq)
	{
		tcp_fd->tf_flags |= TFF_LISTENQ;
		tcp_reply_ioctl(tcp_fd, NW_OK);
		return NW_OK;
	}
	return NW_SUSPEND;
}

/*
find_empty_conn

This function returns a connection that is not inuse.
This includes connections that are never used, and connections without a
user that are not used for a while.
*/

PRIVATE tcp_conn_t *find_empty_conn()
{
	int i;
	tcp_conn_t *tcp_conn;

	for (i=tcp_conf_nr, tcp_conn= tcp_conn_table+i;
		i<TCP_CONN_NR; i++, tcp_conn++)
		/* the first tcp_conf_nr connections are reserved for
		 * RSTs
		 */
	{
		if (tcp_conn->tc_flags == TCF_EMPTY)
		{
			tcp_conn->tc_connInprogress= 0;
			tcp_conn->tc_fd= NULL;
			return tcp_conn;
		}
		if (tcp_conn->tc_fd)
			continue;
		if (tcp_conn->tc_senddis > get_time())
			continue;
		if (tcp_conn->tc_state != TCS_CLOSED)
		{
			 tcp_close_connection (tcp_conn, ENOCONN);
		}
		tcp_conn->tc_flags= 0;
		return tcp_conn;
	}
	return NULL;
}


/*
find_conn_entry

This function return a connection matching locport, locaddr, remport, remaddr.
If no such connection exists NULL is returned.
If a connection exists without mainuser it is closed.
*/

PRIVATE tcp_conn_t *find_conn_entry(locport, locaddr, remport, remaddr)
tcpport_t locport;
ipaddr_t locaddr;
tcpport_t remport;
ipaddr_t remaddr;
{
	tcp_conn_t *tcp_conn;
	int i, state;

	assert(remport);
	assert(remaddr);
	for (i=tcp_conf_nr, tcp_conn= tcp_conn_table+i; i<TCP_CONN_NR;
		i++, tcp_conn++)
		/* the first tcp_conf_nr connections are reserved for
			RSTs */
	{
		if (tcp_conn->tc_flags == TCF_EMPTY)
			continue;
		if (tcp_conn->tc_locport != locport ||
			tcp_conn->tc_locaddr != locaddr ||
			tcp_conn->tc_remport != remport ||
			tcp_conn->tc_remaddr != remaddr)
			continue;
		if (tcp_conn->tc_fd)
			return tcp_conn;
		state= tcp_conn->tc_state;
		if (state != TCS_CLOSED)
		{
			tcp_close_connection(tcp_conn, ENOCONN);
		}
		return tcp_conn;
	}
	return NULL;
}

PRIVATE void read_ip_packets(tcp_port)
tcp_port_t *tcp_port;
{
	int result;

	do
	{
		tcp_port->tp_flags |= TPF_READ_IP;
		result= ip_read(tcp_port->tp_ipfd, TCP_MAX_DATAGRAM);
		if (result == NW_SUSPEND)
		{
			tcp_port->tp_flags |= TPF_READ_SP;
			return;
		}
		assert(result == NW_OK);
		tcp_port->tp_flags &= ~TPF_READ_IP;
	} while(!(tcp_port->tp_flags & TPF_READ_IP));
}

/*
find_best_conn
*/

PRIVATE tcp_conn_t *find_best_conn(ip_hdr, tcp_hdr)
ip_hdr_t *ip_hdr;
tcp_hdr_t *tcp_hdr;
{
	
	int best_level, new_level;
	tcp_conn_t *best_conn, *listen_conn, *tcp_conn;
	tcp_fd_t *tcp_fd;
	int i;
	ipaddr_t locaddr;
	ipaddr_t remaddr;
	tcpport_t locport;
	tcpport_t remport;

	locaddr= ip_hdr->ih_dst;
	remaddr= ip_hdr->ih_src;
	locport= tcp_hdr->th_dstport;
	remport= tcp_hdr->th_srcport;
	if (!remport)	/* This can interfere with a listen, so we reject it
			 * by clearing the requested port 
			 */
		locport= 0;
		
	best_level= 0;
	best_conn= NULL;
	listen_conn= NULL;
	for (i= tcp_conf_nr, tcp_conn= tcp_conn_table+i;
		i<TCP_CONN_NR; i++, tcp_conn++)
		/* the first tcp_conf_nr connections are reserved for
			RSTs */
	{
		if (!(tcp_conn->tc_flags & TCF_INUSE))
			continue;
		/* First fast check for open connections. */
		if (tcp_conn->tc_locaddr == locaddr && 
			tcp_conn->tc_locport == locport &&
			tcp_conn->tc_remport == remport &&
			tcp_conn->tc_remaddr == remaddr &&
			tcp_conn->tc_fd)
		{
			return tcp_conn;
		}

		/* Now check for listens and abandoned connections. */
		if (tcp_conn->tc_locaddr != locaddr)
		{
			continue;
		}
		new_level= 0;
		if (tcp_conn->tc_locport)
		{
			if (tcp_conn->tc_locport != locport)
			{
				continue;
			}
			new_level += 4;
		}
		if (tcp_conn->tc_remport)
		{
			if (tcp_conn->tc_remport != remport)
			{
				continue;
			}
			new_level += 1;
		}
		if (tcp_conn->tc_remaddr)
		{
			if (tcp_conn->tc_remaddr != remaddr)
			{
				continue;
			}
			new_level += 2;
		}
		if (new_level<best_level)
			continue;
		if (new_level != 7 && tcp_conn->tc_state != TCS_LISTEN)
			continue;
		if (new_level == 7)
			/* We found an abandoned connection */
		{
		 	assert(!tcp_conn->tc_fd);
			if (best_conn && tcp_Lmod4G(tcp_conn->tc_ISS,
				best_conn->tc_ISS))
			{
				continue;
			}
			best_conn= tcp_conn;
			continue;
		}
		if (!(tcp_hdr->th_flags & THF_SYN))
			continue;
		best_level= new_level;
		listen_conn= tcp_conn;
		assert(listen_conn->tc_fd != NULL);
	}

	if (listen_conn && listen_conn->tc_fd->tf_flags & TFF_LISTENQ &&
		listen_conn->tc_fd->tf_conn == listen_conn)
	{
		/* Special processing for listen queues. Only accept the 
		 * connection if there is empty space in the queue and
		 * there are empty connections as well.
		 */
		listen_conn= new_conn_for_queue(listen_conn->tc_fd);
	}
	
	if (!best_conn && !listen_conn)
	{
		if ((tcp_hdr->th_flags & THF_SYN) &&
			maybe_listen(locaddr, locport, remaddr, remport))
		{
			/* Quick hack to implement listen back logs:
			 * if a SYN arrives and there is no listen waiting
			 * for that packet, then no reply is sent.
			 */
			return NULL;
		}

		for (i=0, tcp_conn= tcp_conn_table; i<tcp_conf_nr;
			i++, tcp_conn++)
		{
			/* find valid port to send RST */
			if ((tcp_conn->tc_flags & TCF_INUSE) &&
				tcp_conn->tc_locaddr==locaddr)
			{
				break;
			}
		}
		assert (tcp_conn);
		assert (tcp_conn->tc_state == TCS_CLOSED);

		tcp_conn->tc_locport= locport;
		tcp_conn->tc_locaddr= locaddr;
		tcp_conn->tc_remport= remport;
		tcp_conn->tc_remaddr= remaddr;
		assert (!tcp_conn->tc_fd);
		return tcp_conn;
	}

	if (best_conn)
	{
		if (!listen_conn)
		{
			assert(!best_conn->tc_fd);
			return best_conn;
		}

		assert(listen_conn->tc_connInprogress);
		tcp_fd= listen_conn->tc_fd;
		assert(tcp_fd);
		assert((tcp_fd->tf_flags & TFF_LISTENQ) ||
			 tcp_fd->tf_conn == listen_conn);

		if (best_conn->tc_state != TCS_CLOSED)
			tcp_close_connection(best_conn, ENOCONN);