send.c

一款类linux的操作系统源码

/*
 *  Roadrunner/pk
 *    Copyright (C) 1989-2002  Cornfed Systems, Inc.
 *
 *  The Roadrunner/pk operating system is free software; you can
 *  redistribute and/or modify it under the terms of the GNU General
 *  Public License, version 2, as published by the Free Software
 *  Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307 USA
 *
 *  More information about the Roadrunner/pk operating system of
 *  which this file is a part is available on the World-Wide Web
 *  at: http://www.cornfed.com.
 *
 */

#include <errno.h>
#include <fs.h>
#include <net/ether.h>
#include <net/tcp.h>
#if _DEBUG
#include <stdio.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <sys/intr.h>
#include <sys/socket.h>

ssize_t
send(int s, const void *msg, size_t len, int flags)
{
    socket_t socket;
    buf_t b;
    etherhdr_t eh;
    iphdr_t ih;
    tcphdr_t th;
    int datalen, hdrlen, nleft, pos = 0;

    if (s < 0 || s >= FILES)
	return EINVAL;

    if (filetab[s].type != FT_SOCKET)
	return ENOTSOCK;

    socket = (socket_t) filetab[s].data;
    if (socket->state != SS_CONNECTED)
	return ENOTCONN;

    hdrlen = ETHER_HDR_LEN + sizeof(struct iphdr) + sizeof(struct tcphdr);

    datalen = ETHER_PKT_LEN - hdrlen;

    for (nleft = len; nleft > 0;) {
	b = _bget(ETHER_PKT_LEN);
	if (b == NULL)
	    return 0;
	blen(b) = hdrlen;

	eh = (etherhdr_t) bstart(b);
	ih = (iphdr_t) eh->data;
	th = (tcphdr_t) (((char *) ih) + sizeof(struct iphdr));

	bpos(b) = ((char *) th) - bstart(b) + sizeof(struct tcphdr);

	if (nleft >= datalen) {
	    bcopy(((char *) msg) + pos, bstart(b) + bpos(b), datalen);
	    blen(b) += datalen;
	    bpos(b) += datalen;
	    pos += datalen;
	    nleft -= datalen;
	    socket->snd_cc += datalen;
	} else {
	    bcopy(((char *) msg) + pos, bstart(b) + bpos(b), nleft);
	    blen(b) += nleft;
	    socket->snd_cc += nleft;
	    nleft = 0;
	}
	disable;
	benq(b, &(socket->sndq));
	enable;
    }
    tcp_send((tcb_t) socket->pcb);
    return len - nleft;
}