tcp_send.c

minix3的源代码

	DIFBLOCK(0x10, (tcp_conn->tc_fd == 0),
		printf("conn[%d] timeout in abondoned connection\n",
		tcp_conn-tcp_conn_table));

	/* At this point, we have do a retransmission, or send a zero window
	 * probe, which is almost the same.
	 */

	DBLOCK(0x20, printf("tcp_send_timeout: conn[%d] una= %lu, rtt= %ldms\n",
		tcp_conn-tcp_conn_table,
		(unsigned long)tcp_conn->tc_SND_UNA, rtt*1000/HZ));

	/* Update threshold sequence number for retransmission calculation. */
	if (tcp_Gmod4G(tcp_conn->tc_SND_TRM, tcp_conn->tc_rt_threshold))
		tcp_conn->tc_rt_threshold= tcp_conn->tc_SND_TRM;

	tcp_conn->tc_SND_TRM= tcp_conn->tc_SND_UNA;

	if (tcp_conn->tc_flags & TCF_PMTU &&
		curr_time > stt+TCP_PMTU_BLACKHOLE)
	{
		/* We can't tell the difference between a PMTU blackhole 
		 * and a broken link. Assume a PMTU blackhole, and switch
		 * off PMTU discovery.
		 */
		DBLOCK(1, printf(
			"tcp[%d]: PMTU blackhole (or broken link) on route to ",
			tcp_conn-tcp_conn_table);
			writeIpAddr(tcp_conn->tc_remaddr);
			printf(", max mtu = %u\n", tcp_conn->tc_max_mtu););
		tcp_conn->tc_flags &= ~TCF_PMTU;
		tcp_conn->tc_mtutim= curr_time;
		if (tcp_conn->tc_max_mtu > IP_DEF_MTU)
			tcp_conn->tc_mtu= IP_DEF_MTU;
	}

	mss= tcp_conn->tc_mtu-IP_TCP_MIN_HDR_SIZE;
	mss2= 2*mss;

	if (tcp_conn->tc_snd_cwnd == tcp_conn->tc_SND_UNA)
		tcp_conn->tc_snd_cwnd++;
	if (tcp_Gmod4G(tcp_conn->tc_snd_cwnd, tcp_conn->tc_SND_UNA + mss2))
	{
		tcp_conn->tc_snd_cwnd= tcp_conn->tc_SND_UNA + mss2;
		if (tcp_Gmod4G(tcp_conn->tc_SND_TRM, tcp_conn->tc_snd_cwnd))
			tcp_conn->tc_SND_TRM= tcp_conn->tc_snd_cwnd;

		tcp_conn->tc_snd_cthresh /= 2;
		if (tcp_conn->tc_snd_cthresh < mss2)
			tcp_conn->tc_snd_cthresh= mss2;
	}

	if (curr_time-stt > tcp_conn->tc_rt_dead)
	{
		tcp_close_connection(tcp_conn, ETIMEDOUT);
		return;
	}

	timeout= (curr_time-stt) >> 3;
	if (timeout < rtt)
		timeout= rtt;
	timeout += curr_time;

	DBLOCK(0x20, printf(
	"tcp_send_timeout: conn[%d] setting timer to %ld ms (+%ld ms)\n",
		tcp_conn-tcp_conn_table, timeout*1000/HZ,
		(timeout-curr_time)*1000/HZ));

	clck_timer(&tcp_conn->tc_transmit_timer, timeout,
		tcp_send_timeout, tcp_conn-tcp_conn_table);

#if 0
	if (tcp_conn->tc_rt_seq == 0)
	{
		printf("tcp_send_timeout: conn[%d]: setting tc_rt_time\n",
			tcp_conn-tcp_conn_table);
		tcp_conn->tc_rt_time= curr_time-rtt;
		tcp_conn->tc_rt_seq= tcp_conn->tc_SND_UNA;
	}
#endif

	if (tcp_conn->tc_state == TCS_SYN_SENT ||
		(curr_time-stt >= tcp_conn->tc_ttl*HZ))
	{
		new_ttl= tcp_conn->tc_ttl+1;
		if (new_ttl> IP_MAX_TTL)
			new_ttl= IP_MAX_TTL;
		tcp_conn->tc_ttl= new_ttl;
	}

	tcp_conn_write(tcp_conn, 0);
}


PUBLIC void tcp_fd_write(tcp_conn)
tcp_conn_t *tcp_conn;
{
	tcp_fd_t *tcp_fd;
	int urg, nourg, push;
	u32_t max_seq;
	size_t max_trans, write_count;
	acc_t *data, *send_data;

	assert(tcp_conn->tc_busy);
	tcp_fd= tcp_conn->tc_fd;

	if ((tcp_fd->tf_flags & TFF_IOCTL_IP) &&
		!(tcp_fd->tf_flags & TFF_WRITE_IP))
	{
		if (tcp_fd->tf_ioreq != NWIOTCPSHUTDOWN)
			return;
		DBLOCK(0x10, printf("NWIOTCPSHUTDOWN\n"));
		if (tcp_conn->tc_state == TCS_CLOSED)
		{
			tcp_reply_ioctl (tcp_fd, tcp_conn->tc_error);
			return;
		}
		if (!(tcp_conn->tc_flags & TCF_FIN_SENT))
		{
			DBLOCK(0x10, printf("calling tcp_shutdown\n"));
			tcp_shutdown (tcp_conn);
		}
		else
		{
			if (tcp_conn->tc_SND_UNA == tcp_conn->tc_SND_NXT)
			{
				tcp_reply_ioctl (tcp_fd, NW_OK);
				DBLOCK(0x10, printf("shutdown completed\n"));
			}
			else
			{
				DBLOCK(0x10,
					printf("shutdown still inprogress\n"));
			}
		}
		return;
	}

	assert (tcp_fd->tf_flags & TFF_WRITE_IP);
	if (tcp_conn->tc_state == TCS_CLOSED)
	{
		if (tcp_fd->tf_write_offset)
		{
			tcp_reply_write(tcp_fd,
				tcp_fd->tf_write_offset);
		}
		else
			tcp_reply_write(tcp_fd, tcp_conn->tc_error);
		return;
	}

	urg= (tcp_fd->tf_flags & TFF_WR_URG);
	push= (tcp_fd->tf_flags & TFF_PUSH_DATA);

	max_seq= tcp_conn->tc_SND_UNA + TCP_MAX_SND_WND_SIZE;
	max_trans= max_seq - tcp_conn->tc_SND_NXT;
	if (tcp_fd->tf_write_count <= max_trans)
		write_count= tcp_fd->tf_write_count;
	else
		write_count= max_trans;
	if (write_count)
	{
		if (tcp_conn->tc_flags & TCF_BSD_URG)
		{
			if (tcp_Gmod4G(tcp_conn->tc_SND_NXT,
				tcp_conn->tc_SND_UNA))
			{
				nourg= tcp_LEmod4G(tcp_conn->tc_SND_UP,
					tcp_conn->tc_SND_UNA);
				if ((urg && nourg) || (!urg && !nourg))
				{
					DBLOCK(0x20,
						printf("not sending\n"));
					return;
				}
			}
		}
		data= (*tcp_fd->tf_get_userdata)
			(tcp_fd->tf_srfd, tcp_fd->tf_write_offset,
			write_count, FALSE);

		if (!data)
		{
			if (tcp_fd->tf_write_offset)
			{
				tcp_reply_write(tcp_fd,
					tcp_fd->tf_write_offset);
			}
			else
				tcp_reply_write(tcp_fd, EFAULT);
			return;
		}
		tcp_fd->tf_write_offset += write_count;
		tcp_fd->tf_write_count -= write_count;

		send_data= tcp_conn->tc_send_data;
		tcp_conn->tc_send_data= 0;
		send_data= bf_append(send_data, data);
		tcp_conn->tc_send_data= send_data;
		tcp_conn->tc_SND_NXT += write_count;
		if (urg)
		{
			if (tcp_conn->tc_flags & TCF_BSD_URG)
				tcp_conn->tc_SND_UP= tcp_conn->tc_SND_NXT;
			else
				tcp_conn->tc_SND_UP= tcp_conn->tc_SND_NXT-1;
		}
		if (push && !tcp_fd->tf_write_count)
			tcp_conn->tc_SND_PSH= tcp_conn->tc_SND_NXT;
	}
	if (!tcp_fd->tf_write_count)
	{
		tcp_reply_write(tcp_fd, tcp_fd->tf_write_offset);
	}
}

PUBLIC unsigned tcp_sel_write(tcp_conn)
tcp_conn_t *tcp_conn;
{
	tcp_fd_t *tcp_fd;
	int urg, nourg;
	u32_t max_seq;
	size_t max_trans;

	tcp_fd= tcp_conn->tc_fd;

	if (tcp_conn->tc_state == TCS_CLOSED)
		return 1;
	
	urg= (tcp_fd->tf_flags & TFF_WR_URG);

	max_seq= tcp_conn->tc_SND_UNA + TCP_MAX_SND_WND_SIZE;
	max_trans= max_seq - tcp_conn->tc_SND_NXT;
	if (max_trans)
	{
		if (tcp_conn->tc_flags & TCF_BSD_URG)
		{
			if (tcp_Gmod4G(tcp_conn->tc_SND_NXT,
				tcp_conn->tc_SND_UNA))
			{
				nourg= tcp_LEmod4G(tcp_conn->tc_SND_UP,
					tcp_conn->tc_SND_UNA);
				if ((urg && nourg) || (!urg && !nourg))
				{
					DBLOCK(0x20,
						printf("not sending\n"));
					return 0;
				}
			}
		}
		return 1;
	}

	return 0;
}

PUBLIC void
tcp_rsel_write(tcp_conn)
tcp_conn_t *tcp_conn;
{
	tcp_fd_t *tcp_fd;

	if (tcp_sel_write(tcp_conn) == 0)
		return;

	tcp_fd= tcp_conn->tc_fd;
	tcp_fd->tf_flags &= ~TFF_SEL_WRITE;
	if (tcp_fd->tf_select_res)
		tcp_fd->tf_select_res(tcp_fd->tf_srfd, SR_SELECT_WRITE);
	else
		printf("tcp_rsel_write: no select_res\n");
}

/*
tcp_shutdown
*/

PUBLIC void tcp_shutdown(tcp_conn)
tcp_conn_t *tcp_conn;
{
	switch (tcp_conn->tc_state)
	{
	case TCS_CLOSED:
	case TCS_LISTEN:
	case TCS_SYN_SENT:
	case TCS_SYN_RECEIVED:
		tcp_close_connection(tcp_conn, ENOTCONN);
		return;
	}

	if (tcp_conn->tc_flags & TCF_FIN_SENT)
		return;
	tcp_conn->tc_flags |= TCF_FIN_SENT;
	tcp_conn->tc_flags &= ~TCF_NO_PUSH;
	tcp_conn->tc_SND_NXT++;
	tcp_conn->tc_SND_PSH= tcp_conn->tc_SND_NXT;

	assert (tcp_check_conn(tcp_conn) ||
		(tcp_print_conn(tcp_conn), printf("\n"), 0));

	tcp_conn_write(tcp_conn, 1);

	/* Start the timer */
	tcp_set_send_timer(tcp_conn);
}

PUBLIC void tcp_set_send_timer(tcp_conn)
tcp_conn_t *tcp_conn;
{
	clock_t curr_time;
	clock_t rtt;

	assert(tcp_conn->tc_state != TCS_CLOSED);
	assert(tcp_conn->tc_state != TCS_LISTEN);

	curr_time= get_time();
	rtt= tcp_conn->tc_rtt;

	DBLOCK(0x20, printf(
	"tcp_set_send_timer: conn[%d] setting timer to %ld ms (+%ld ms)\n",
		tcp_conn-tcp_conn_table,
		(curr_time+rtt)*1000/HZ, rtt*1000/HZ));

	/* Start the timer */
	clck_timer(&tcp_conn->tc_transmit_timer,
		curr_time+rtt, tcp_send_timeout, tcp_conn-tcp_conn_table);
	tcp_conn->tc_stt= curr_time;
}

/*
tcp_close_connection

*/

PUBLIC void tcp_close_connection(tcp_conn, error)
tcp_conn_t *tcp_conn;
int error;
{
	int i;
	tcp_port_t *tcp_port;
	tcp_fd_t *tcp_fd;
	tcp_conn_t *tc;

	assert (tcp_check_conn(tcp_conn) ||
		(tcp_print_conn(tcp_conn), printf("\n"), 0));
	assert (tcp_conn->tc_flags & TCF_INUSE);

	tcp_conn->tc_error= error;
	tcp_port= tcp_conn->tc_port;
	tcp_fd= tcp_conn->tc_fd;
	if (tcp_conn->tc_state == TCS_CLOSED)
		return;

	tcp_conn->tc_state= TCS_CLOSED;
	DBLOCK(0x10, tcp_print_state(tcp_conn); printf("\n"));

	if (tcp_fd && (tcp_fd->tf_flags & TFF_LISTENQ))
	{
		for (i= 0; i<TFL_LISTEN_MAX; i++)
		{
			if (tcp_fd->tf_listenq[i] == tcp_conn)
				break;
		}
		assert(i < TFL_LISTEN_MAX);
		tcp_fd->tf_listenq[i]= NULL;

		assert(tcp_conn->tc_connInprogress);
		tcp_conn->tc_connInprogress= 0;

		tcp_conn->tc_fd= NULL;
		tcp_fd= NULL;
	}
	else if (tcp_fd)
	{

		tcp_conn->tc_busy++;
		assert(tcp_fd->tf_conn == tcp_conn);

		if (tcp_fd->tf_flags & TFF_READ_IP)
			tcp_fd_read (tcp_conn, 1);
		assert (!(tcp_fd->tf_flags & TFF_READ_IP));
		if (tcp_fd->tf_flags & TFF_SEL_READ)
			tcp_rsel_read (tcp_conn);

		if (tcp_fd->tf_flags & TFF_WRITE_IP)
		{
			tcp_fd_write(tcp_conn);
			tcp_conn_write(tcp_conn, 1);
		}
		assert (!(tcp_fd->tf_flags & TFF_WRITE_IP));
		if (tcp_fd->tf_flags & TFF_IOCTL_IP)
		{
			tcp_fd_write(tcp_conn);
			tcp_conn_write(tcp_conn, 1);
		}
		if (tcp_fd->tf_flags & TFF_IOCTL_IP)
			assert(tcp_fd->tf_ioreq != NWIOTCPSHUTDOWN);
		if (tcp_fd->tf_flags & TFF_SEL_WRITE) 
			tcp_rsel_write(tcp_conn);

		if (tcp_conn->tc_connInprogress)
			tcp_restart_connect(tcp_conn);
		assert (!tcp_conn->tc_connInprogress);
		assert (!(tcp_fd->tf_flags & TFF_IOCTL_IP) ||
			(printf("req= 0x%lx\n",
			(unsigned long)tcp_fd->tf_ioreq), 0));
		tcp_conn->tc_busy--;
	}

	if (tcp_conn->tc_rcvd_data)
	{
		bf_afree(tcp_conn->tc_rcvd_data);
		tcp_conn->tc_rcvd_data= NULL;
	}
	tcp_conn->tc_flags &= ~TCF_FIN_RECV;
	tcp_conn->tc_RCV_LO= tcp_conn->tc_RCV_NXT;

	if (tcp_conn->tc_adv_data)
	{
		bf_afree(tcp_conn->tc_adv_data);
		tcp_conn->tc_adv_data= NULL;
	}

	if (tcp_conn->tc_send_data)
	{
		bf_afree(tcp_conn->tc_send_data);
		tcp_conn->tc_send_data= NULL;
		tcp_conn->tc_SND_TRM=
			tcp_conn->tc_SND_NXT= tcp_conn->tc_SND_UNA;
	}
	tcp_conn->tc_SND_TRM= tcp_conn->tc_SND_NXT= tcp_conn->tc_SND_UNA;

	if (tcp_conn->tc_remipopt)
	{
		bf_afree(tcp_conn->tc_remipopt);
		tcp_conn->tc_remipopt= NULL;
	}

	if (tcp_conn->tc_tcpopt)
	{
		bf_afree(tcp_conn->tc_tcpopt);
		tcp_conn->tc_tcpopt= NULL;
	}

	if (tcp_conn->tc_frag2send)
	{
		bf_afree(tcp_conn->tc_frag2send);
		tcp_conn->tc_frag2send= NULL;
	}
	if (tcp_conn->tc_flags & TCF_MORE2WRITE)
	{
		for (tc= tcp_port->tp_snd_head; tc; tc= tc->tc_send_link)
		{
			if (tc->tc_send_link == tcp_conn)
				break;
		}
		if (tc == NULL)
		{
			assert(tcp_port->tp_snd_head == tcp_conn);
			tcp_port->tp_snd_head= tcp_conn->tc_send_link;
		}
		else
		{
			tc->tc_send_link= tcp_conn->tc_send_link;
			if (tc->tc_send_link == NULL)
				tcp_port->tp_snd_tail= tc;
		}
		tcp_conn->tc_flags &= ~TCF_MORE2WRITE;
	}

	clck_untimer (&tcp_conn->tc_transmit_timer);
	tcp_conn->tc_transmit_seq= 0;

					/* clear all flags but TCF_INUSE */
	tcp_conn->tc_flags &= TCF_INUSE;
	assert (tcp_check_conn(tcp_conn));
}

/*
 * $PchId: tcp_send.c,v 1.32 2005/06/28 14:21:52 philip Exp $
 */