tcp_send.c

minux的源代码,一个非常小的操作系统

		{
			tcp_conn->tc_rtt= tcp_conn->tc_rtt/2+1;
assert (tcp_conn->tc_rtt);
		}

		if (seg_ack == tcp_conn->tc_SND_NXT)
			tcp_conn->tc_ett= 0;
		else
		{
			tcp_conn->tc_ett += (seg_ack-tcp_conn->
				tc_SND_UNA) * tcp_conn->tc_rtt /
				(tcp_conn->tc_SND_NXT-tcp_conn->
				tc_SND_UNA);
		}
		queue_lo= tcp_conn->tc_SND_UNA;
		queue_hi= tcp_conn->tc_SND_NXT;

		tcp_conn->tc_SND_UNA= seg_ack;
		if (tcp_Lmod4G(tcp_conn->tc_SND_TRM, seg_ack))
			tcp_conn->tc_SND_TRM= seg_ack;
		if (tcp_Lmod4G(tcp_conn->tc_snd_cwnd, seg_ack))
		{
			tcp_conn->tc_snd_cwnd= seg_ack;
#if DEBUG & 256
 { where(); printf("snd_cwnd is now %d\n", tcp_conn->tc_snd_cwnd); }
#endif
		}

		if (queue_lo == tcp_conn->tc_ISS)
			queue_lo++;

		if (tcp_conn->tc_flags & TCF_FIN_SENT)
		{
			if (seg_ack == queue_hi)
				seg_ack--;
			if (queue_lo == queue_hi)
				queue_lo--;
			queue_hi--;
		}

		offset= seg_ack - queue_lo;
		size= queue_hi - seg_ack;
		old_pack= tcp_conn->tc_send_data;
		tcp_conn->tc_send_data= 0;

		if (!size)
		{
			new_pack= 0;
			tcp_conn->tc_snd_cwnd= tcp_conn->tc_SND_UNA + 
				2*tcp_conn->tc_mss;
			/* Reset window if a write is completed */
#if DEBUG & 256
 { where(); printf("snd_cwnd is now %d\n", tcp_conn->tc_snd_cwnd); }
#endif
		}
		else
			new_pack= bf_cut(old_pack, offset, size);
		bf_afree(old_pack);
		tcp_conn->tc_send_data= new_pack;
assert (tcp_check_conn(tcp_conn));

		if (tcp_conn->tc_state == TCS_CLOSED)
		{
	 { where(); printf("connection closed while inuse\n"); }
			return;
		}

		if (tcp_conn->tc_ett)
		{
#if DEBUG & 256
 { where(); printf("setting major_to\n"); }
#endif
			clck_timer(&tcp_conn->tc_major_timer,
			tcp_conn->tc_ett + tcp_conn->tc_rtt,
			major_to, tcp_conn-tcp_conn_table);
		}
	}

	mss= tcp_conn->tc_mss;
	cthresh= tcp_conn->tc_snd_cthresh;
	mss2= 2*mss;

	if (new_win < mss2)
	{
		cwnd= 0;
		if (new_win >= mss)
			incr= mss;
		else
		{
			if (new_win)
				incr= new_win;
			else
				incr= 1;
		}
	}
	else
	{
		cwnd= tcp_conn->tc_snd_cwnd - tcp_conn->tc_SND_UNA;
		incr= mss2;
		if (cwnd+incr > new_win)
		{
			incr= mss;
			if (cwnd+incr > new_win)
				incr= 0;
		}
	}

assert (cthresh >= mss2);

	if (incr && cwnd+incr >  cthresh)
	{
		incr -= mss;
		if (incr && cwnd+incr >  cthresh)
			incr -= mss;
	}
	if (cwnd+incr+mss>cthresh && cthresh<tcp_conn->tc_snd_wnd)
		tcp_conn->tc_snd_cthresh += tcp_conn->tc_snd_cinc;

	tcp_conn->tc_snd_cwnd= tcp_conn->tc_SND_UNA+cwnd+incr;
#if DEBUG & 256
 { where(); printf("snd_cwnd is now 0x%x\n", tcp_conn->tc_snd_cwnd); }
#endif
	if (tcp_Gmod4G(tcp_conn->tc_SND_TRM, tcp_conn->tc_snd_cwnd))
		tcp_conn->tc_SND_TRM= tcp_conn->tc_snd_cwnd;

	if (tcp_Gmod4G(tcp_conn->tc_snd_cwnd, tcp_conn->tc_SND_TRM) &&
		tcp_Gmod4G(tcp_conn->tc_SND_NXT, tcp_conn->tc_SND_TRM))
		tcp_restart_write(tcp_conn);

	if (tcp_conn->tc_writeuser)
		tcp_restart_fd_write(tcp_conn);

assert (tcp_check_conn(tcp_conn));

}

PUBLIC void tcp_restart_fd_write(tcp_conn)
tcp_conn_t *tcp_conn;
{
	tcp_fd_t *urgent_fd, *normal_fd, *shutdown_fd,
		*new_fd, *hi_fd, *tcp_fd;
	int closed_connection;

#if DEBUG & 256
 { where(); printf("in restart_fd_write\n"); }
#endif
	do
	{
		tcp_fd= tcp_conn->tc_writeuser;

		closed_connection= (tcp_conn->tc_state == TCS_CLOSED);
		if (tcp_fd)
			fd_write(tcp_fd);
		else
			tcp_fd= &tcp_fd_table[TCP_FD_NR-1];

		if (!closed_connection &&
			tcp_conn->tc_state == TCS_CLOSED)
		{
#if DEBUG
  { where(); printf("connection closed while inuse\n"); }
#endif
			return;
		}

		if (!tcp_conn->tc_writeuser)
		{
			urgent_fd= 0;
			normal_fd= 0;
			shutdown_fd= 0;
			for (new_fd= tcp_fd+1, hi_fd=
				&tcp_fd_table[TCP_FD_NR]; new_fd<hi_fd;
				new_fd++)
				switch_write_fd(tcp_conn, new_fd,
					&urgent_fd, &normal_fd,
					&shutdown_fd);
			for (new_fd= tcp_fd_table, hi_fd= tcp_fd+1;
				new_fd < hi_fd; new_fd++)
				switch_write_fd(tcp_conn, new_fd,
					&urgent_fd, &normal_fd,
					&shutdown_fd);
			if (urgent_fd)
				tcp_fd= urgent_fd;
			else if (normal_fd)
				tcp_fd= normal_fd;
			else
				tcp_fd= shutdown_fd;
			tcp_conn->tc_writeuser= tcp_fd;
		}
		else
			return;
	} while (tcp_conn->tc_writeuser);
}



PRIVATE void switch_write_fd (tcp_conn, new_fd, ref_urg_fd,
	ref_norm_fd, ref_shut_fd)
tcp_conn_t *tcp_conn;
tcp_fd_t *new_fd, **ref_urg_fd, **ref_norm_fd, **ref_shut_fd;
{
	if (!(new_fd->tf_flags & TFF_INUSE))
		return;
	if (new_fd->tf_conn != tcp_conn)
		return;
	if (new_fd->tf_flags & TFF_WRITE_IP)
		if (new_fd->tf_flags & TFF_WR_URG)
		{
			if (!*ref_urg_fd)
				*ref_urg_fd= new_fd;
		}
		else
		{
			if (!*ref_norm_fd)
				*ref_norm_fd= new_fd;
		}
	else if ((new_fd->tf_flags & TFF_IOCTL_IP) &&
		new_fd->tf_ioreq == NWIOTCPSHUTDOWN)
		if (!*ref_shut_fd)
			*ref_shut_fd= new_fd;
}

PRIVATE void fd_write (tcp_fd)
tcp_fd_t *tcp_fd;
{
	tcp_conn_t *tcp_conn;
	int urg, push;
	u32_t max_seq;
	size_t max_count, max_trans, write_count, send_count;
	acc_t *data, *tmp_acc, *send_data;
	int restart_write;

	restart_write= FALSE;
	tcp_conn= tcp_fd->tf_conn;

	if (tcp_fd->tf_flags & TFF_IOCTL_IP)
	{
assert (tcp_fd->tf_ioreq == NWIOTCPSHUTDOWN);
		if (tcp_conn->tc_state == TCS_CLOSED)
		{
			tcp_conn->tc_writeuser= 0;
			tcp_reply_ioctl (tcp_fd, tcp_conn->tc_error);
			return;
		}
		tcp_conn->tc_writeuser= 0;
		tcp_reply_ioctl (tcp_fd, NW_OK);
		tcp_shutdown (tcp_conn);
		return;
	}
	assert (tcp_fd->tf_flags & TFF_WRITE_IP);
	if (tcp_conn->tc_state == TCS_CLOSED)
	{
		tcp_conn->tc_writeuser= 0;
#if DEBUG & 256
 { where(); printf("calling tcp_reply_write()\n"); }
#endif
		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;
	}
assert (!(tcp_conn->tc_flags & TCF_FIN_SENT));
assert (tcp_conn->tc_SND_UNA != tcp_conn->tc_ISS);

	urg= (tcp_fd->tf_flags & TFF_WR_URG);
	push= (tcp_fd->tf_flags & TFF_PUSH_DATA);
#if DEBUG & 256
 if (push) { where(); printf("pushing data\n"); }
#endif

	max_seq= tcp_conn->tc_SND_UNA + tcp_conn->tc_snd_wnd;
	if (urg)
		max_seq += tcp_conn->tc_urg_wnd;
	max_count= max_seq - tcp_conn->tc_SND_UNA;
	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 if (!urg && max_trans < max_count/2)
		return;
	else
		write_count= max_trans;
	if (write_count)
	{
		data= (*tcp_fd->tf_get_userdata)
			(tcp_fd->tf_srfd, tcp_fd->tf_write_offset,
			write_count, FALSE);
		if (tcp_conn->tc_state == TCS_CLOSED)
		{
 { where(); printf("connection closed while inuse\n"); }
			if (data)
				bf_afree(data);
			return;
		}
		if (!data)
		{
			tcp_conn->tc_writeuser= 0;
assert(data);
#if DEBUG
 { where(); printf("calling tcp_reply_write()\n"); }
#endif
			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);
		if (tcp_conn->tc_state == TCS_CLOSED)
		{
 { where(); printf("connection closed while inuse\n"); }
			bf_afree(send_data);
			return;
		}
		tcp_conn->tc_send_data= send_data;
		tcp_conn->tc_SND_NXT += write_count;
		if (urg)
			tcp_conn->tc_SND_UP= tcp_conn->tc_SND_NXT;
		if (push && !tcp_fd->tf_write_count)
			tcp_conn->tc_SND_PSH= tcp_conn->tc_SND_NXT;

assert (tcp_check_conn(tcp_conn));
		if (tcp_Gmod4G(tcp_conn->tc_SND_NXT, tcp_conn->tc_SND_TRM) &&
			tcp_Lmod4G(tcp_conn->tc_SND_TRM, tcp_conn->tc_snd_cwnd))
			restart_write= TRUE;
	}
	if (!tcp_fd->tf_write_count)
	{
		tcp_conn->tc_writeuser= 0;
#if DEBUG & 256
 { where(); printf("calling tcp_reply_write()\n"); }
#endif
		tcp_reply_write(tcp_fd, tcp_fd->tf_write_offset);
	}
	if (restart_write)
		tcp_restart_write(tcp_conn);
}

PUBLIC void tcp_shutdown(tcp_conn)
tcp_conn_t *tcp_conn;
{
	int closed_connection;

#if DEBUG & 256
 { where(); printf("in tcp_shutdown\n"); }
#endif
	if (tcp_conn->tc_flags & TCF_FIN_SENT)
		return;
	tcp_conn->tc_flags |= TCF_FIN_SENT;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif
	tcp_conn->tc_SND_NXT++;

	switch (tcp_conn->tc_state)
	{
	case TCS_CLOSED:
	case TCS_LISTEN:
	case TCS_SYN_SENT:
	case TCS_SYN_RECEIVED:
#if DEBUG & 256
 { where(); printf("calling tcp_close_connection\n"); }
#endif
		tcp_close_connection(tcp_conn, ENOTCONN);
		break;
	case TCS_ESTABLISHED:
		tcp_conn->tc_state= TCS_FIN_WAIT_1;
#if DEBUG
 { where(); tcp_write_state(tcp_conn); }
#endif
		break;
	case TCS_CLOSE_WAIT:
		tcp_conn->tc_state= TCS_LAST_ACK;
#if DEBUG
 { where(); tcp_write_state(tcp_conn); }
#endif
		break;
	}
	closed_connection= (tcp_conn->tc_state == TCS_CLOSED);

assert (tcp_check_conn(tcp_conn));

#if DEBUG & 256
 { where(); printf("calling tcp_restart_write\n"); }
#endif
		tcp_restart_write(tcp_conn);
}

PUBLIC void tcp_set_time_wait_timer(tcp_conn)
tcp_conn_t *tcp_conn;
{
	assert (tcp_conn->tc_state == TCS_TIME_WAIT);

#if DEBUG & 256
 { where(); printf("tcp_set_time_wait_timer, ttl= %d\n", tcp_conn->tc_ttl); }
#endif
	clck_timer(&tcp_conn->tc_time_wait_timer, get_time() +
		tcp_conn->tc_ttl * 2L * HZ, time_wait_to, tcp_conn-
		tcp_conn_table);
}

PUBLIC void tcp_set_ack_timer (tcp_conn)
tcp_conn_t *tcp_conn;
{
	if (tcp_conn->tc_flags & TCF_ACK_TIMER_SET)
		return;

	tcp_conn->tc_flags |= TCF_ACK_TIMER_SET;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif

#if DEBUG & 256
 { where(); printf("setting ack_timer\n"); };
#endif
	clck_timer(&tcp_conn->tc_ack_timer, get_time() +
		TCP_ACK_DELAY, ack_to, tcp_conn-tcp_conn_table);
}

/*
tcp_close_connection

*/

PUBLIC void tcp_close_connection(tcp_conn, error)
tcp_conn_t *tcp_conn;
int error;
{
#if DEBUG & 256
 { where(); printf("closing connection\n"); }
#endif

assert (tcp_check_conn(tcp_conn));
assert (tcp_conn->tc_flags & TCF_INUSE);

	tcp_conn->tc_error= error;
	if (tcp_conn->tc_state == TCS_CLOSED)
		return;

	clck_untimer (&tcp_conn->tc_major_timer);
	clck_untimer (&tcp_conn->tc_minor_timer);
#if DEBUG & 256
 { where(); printf("clearing ack_timer\n"); }
#endif
	clck_untimer (&tcp_conn->tc_ack_timer);
	clck_untimer (&tcp_conn->tc_time_wait_timer);

	tcp_conn->tc_state= TCS_CLOSED;
#if DEBUG & 16
 { where(); tcp_write_state(tcp_conn); }
#endif

	if (tcp_conn->tc_readuser)
		tcp_restart_fd_read (tcp_conn);
assert (!tcp_conn->tc_readuser);

	if (tcp_conn->tc_writeuser)
		tcp_restart_fd_write (tcp_conn);
assert (!tcp_conn->tc_writeuser);

	if (tcp_conn->tc_connuser)
	{
#if DEBUG & 256
 { where(); printf("closing and connuser present\n"); }
#endif
		tcp_restart_connect (tcp_conn->tc_connuser);
	}
assert (!tcp_conn->tc_connuser);

	if (tcp_conn->tc_rcvd_data)
	{
		bf_afree(tcp_conn->tc_rcvd_data);
		tcp_conn->tc_rcvd_data= 0;
	}
	tcp_conn->tc_flags &= ~TCF_FIN_RECV;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif
	tcp_conn->tc_RCV_LO= tcp_conn->tc_RCV_NXT;

	if (tcp_conn->tc_rcv_queue)
	{
		bf_afree(tcp_conn->tc_rcv_queue);
		tcp_conn->tc_rcv_queue= 0;
	}

	if (tcp_conn->tc_send_data)
	{
#if DEBUG & 256
 { where(); printf("releasing data\n"); }
#endif
#if DEBUG & 256
 { where(); printf("SND_TRM= 0x%lx, tc_SND_NXT= 0x%lx, SND_UNA=  0x%lx\n",
	tcp_conn->tc_SND_TRM, tcp_conn->tc_SND_NXT, tcp_conn->tc_SND_UNA); }
#endif
		bf_afree(tcp_conn->tc_send_data);
		tcp_conn->tc_send_data= 0;
		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= 0;
	}

	if (tcp_conn->tc_remtcpopt)
	{
		bf_afree(tcp_conn->tc_remtcpopt);
		tcp_conn->tc_remtcpopt= 0;
	}

	if (tcp_conn->tc_frag2send)
	{
		bf_afree(tcp_conn->tc_frag2send);
		tcp_conn->tc_remtcpopt= 0;
	}
					/* clear all flags but TCF_INUSE */
	tcp_conn->tc_flags &= TCF_INUSE;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif
assert (tcp_check_conn(tcp_conn));
}

PRIVATE void ack_to(conn, timer)
int conn;
struct timer *timer;
{
	tcp_conn_t *tcp_conn;

#if DEBUG & 256
 { where(); printf("in ack_to\n"); }
#endif
	tcp_conn= &tcp_conn_table[conn];

	assert (&tcp_conn->tc_ack_timer == timer);

	assert (tcp_conn->tc_flags & TCF_ACK_TIMER_SET);

	tcp_conn->tc_flags &= ~TCF_ACK_TIMER_SET;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif
	tcp_conn->tc_flags |= TCF_SEND_ACK;
#if DEBUG & 256
 { where(); printf("tcp_conn_table[%d].tc_flags= 0x%x\n", 
	tcp_conn-tcp_conn_table, tcp_conn->tc_flags); }
#endif
	tcp_restart_write (tcp_conn);
}

PRIVATE void time_wait_to(conn, timer)
int conn;
struct timer *timer;
{
	tcp_conn_t *tcp_conn;

	tcp_conn= &tcp_conn_table[conn];

	assert (tcp_conn->tc_state == TCS_TIME_WAIT);
	assert (&tcp_conn->tc_time_wait_timer == timer);

#if DEBUG
 { where(); printf("calling tcp_close_connection\n"); }
#endif
	tcp_close_connection (tcp_conn, ENOCONN);
}

PUBLIC void tcp_zero_wnd_to(conn, timer)
int conn;
struct timer *timer;
{
	tcp_conn_t *tcp_conn;

#if DEBUG & 256
 { where(); printf("in tcp_zero_wnd_to\n"); }
#endif
	tcp_conn= &tcp_conn_table[conn];

	assert (&tcp_conn->tc_major_timer == timer);
	assert (tcp_conn->tc_0wnd_to);

	tcp_conn->tc_0wnd_to *= 2;
	tcp_conn->tc_SND_TRM= tcp_conn->tc_SND_UNA;

	tcp_restart_write (tcp_conn);
}

#if DEBUG
PRIVATE void tcp_delay_to(ref, timer)
int ref;
timer_t *timer;
{
	tcp_port_t *tcp_port;

assert(ref >= 0 && ref < TCP_PORT_NR);
	tcp_port= &tcp_port_table[ref];
assert(timer == &tcp_port->tp_delay_tim);

	tcp_port->tp_flags &= ~(TPF_WRITE_SP|TPF_WRITE_IP);
	tcp_port->tp_flags |= TPF_DELAY_TCP;
	if (tcp_port->tp_flags & TPF_MORE2WRITE)
	{
#if DEBUG & 256
{ where(); printf("calling tcp_restart_write_port\n"); }
#endif
		write2port(tcp_port, tcp_port->tp_pack);
	}
}
#endif