tcpsndlen.c,v

来自「TCP-IP红宝书源代码」· C,V 代码 · 共 119 行

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1.2
date	97.09.21.19.29.52;	author dls;	state Dist;
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next	1.1;

1.1
date	94.01.14.03.51.20;	author dls;	state v2e1;
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@pre-3e code
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@/* tcpsndlen.c - tcpsndlen */

#include <conf.h>
#include <kernel.h>
#include <network.h>
#include <q.h>

struct	uqe	*uqalloc();

/*------------------------------------------------------------------------
 *  tcpsndlen - compute the packet length and offset in sndbuf
 *------------------------------------------------------------------------
 */
int tcpsndlen(ptcb, rexmt, poff)
struct	tcb	*ptcb;
Bool	rexmt;
int	*poff;
{
	struct 	uqe	*puqe, *puqe2;
	int		datalen;

	if (rexmt || (ptcb->tcb_code & TCPF_SYN))
		*poff = 0;
	else
		*poff = ptcb->tcb_snext - ptcb->tcb_suna;
	datalen = ptcb->tcb_sbcount - *poff;
	datalen = min(datalen, ptcb->tcb_swindow);
	return min(datalen, ptcb->tcb_smss);
}
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@Initial revision
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@d22 7
a28 50
	if (rexmt || ptcb->tcb_sudq == EMPTY) {
		if (rexmt || (ptcb->tcb_code & TCPF_SYN))
			*poff = 0;
		else
			*poff = ptcb->tcb_snext - ptcb->tcb_suna;
		datalen = ptcb->tcb_sbcount - *poff;
		/* remove urgent data holes */
		if (!rexmt) {
			datalen = tcpshskip(ptcb, datalen, poff);
			datalen = min(datalen, ptcb->tcb_swindow);
		}
		return min(datalen, ptcb->tcb_smss);
	}
	/* else, URGENT data */

	puqe = (struct uqe *)deq(ptcb->tcb_sudq);
	*poff = ptcb->tcb_sbstart + puqe->uq_seq - ptcb->tcb_suna;
	if (*poff > ptcb->tcb_sbsize)
		*poff -= ptcb->tcb_sbsize;
	datalen = puqe->uq_len;
	if (datalen > ptcb->tcb_smss) {
		datalen = ptcb->tcb_smss;
		puqe2 = uqalloc();
		if ((int)puqe2 == SYSERR) {
			uqfree(puqe);		/* bail out and		*/
			return ptcb->tcb_smss;	/* try as normal data	*/
		}
		puqe2->uq_seq = puqe->uq_seq;
		puqe2->uq_len = datalen;

		/* put back what we can't use */
		puqe->uq_seq += datalen;
		puqe->uq_len -= datalen;
	} else {
		puqe2 = puqe;
		puqe = (struct uqe *)deq(ptcb->tcb_sudq);
	}
	if (puqe == 0) {
		freeq(ptcb->tcb_sudq);
		ptcb->tcb_sudq = -1;
	} else if (enq(ptcb->tcb_sudq, puqe,
			SUDK(ptcb, puqe->uq_seq)) < 0)
		uqfree(puqe);	/* shouldn't happen */
	if (ptcb->tcb_suhq == EMPTY) {
		ptcb->tcb_suhq = newq(TCPUQLEN, QF_WAIT);
		ptcb->tcb_suhseq = puqe2->uq_seq;
	}
	if (enq(ptcb->tcb_suhq, puqe2, SUHK(ptcb, puqe2->uq_seq)) < 0)
		uqfree(puqe2);
	return datalen;
@