tcpacked.c,v

来自「TCP-IP红宝书源代码」· C,V 代码 · 共 97 行

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date	97.09.21.19.29.52;	author dls;	state Dist;
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date	94.01.14.03.51.20;	author dls;	state v2e1;
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@/* tcpacked.c - tcpacked */

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

/*------------------------------------------------------------------------
 *  tcpacked - handle in-bound ACKs and do round trip estimates
 *------------------------------------------------------------------------
 */
int tcpacked(ptcb, pep)
struct	tcb	*ptcb;
struct	ep	*pep;
{
	struct	ip	*pip = (struct ip *)pep->ep_data;
	struct	tcp	*ptcp = (struct tcp *)pip->ip_data;
	int		acked, tcbnum, cacked;
	STATWORD	ps;

	if (!(ptcp->tcp_code & TCPF_ACK))
		return SYSERR;
	acked = ptcp->tcp_ack - ptcb->tcb_suna;
	cacked = 0;
	if (acked <= 0)
		return 0;	/* duplicate ACK */
	if (SEQCMP(ptcp->tcp_ack, ptcb->tcb_snext) > 0)
		if (ptcb->tcb_state == TCPS_SYNRCVD)
			return tcpreset(pep);
		else
			return tcpackit(ptcb, pep);
	tcprtt(ptcb);
	ptcb->tcb_suna = ptcp->tcp_ack;
	if (acked && ptcb->tcb_code & TCPF_SYN) {
		acked--;
		cacked++;
		ptcb->tcb_code &= ~TCPF_SYN;
		ptcb->tcb_flags &= ~TCBF_FIRSTSEND;
	}
	if ((ptcb->tcb_code & TCPF_FIN) &&
	    SEQCMP(ptcp->tcp_ack, ptcb->tcb_snext) == 0) {
		acked--;
		cacked++;
		ptcb->tcb_code &= ~TCPF_FIN;
		ptcb->tcb_flags &= ~TCBF_SNDFIN;
	}
	if ((ptcb->tcb_flags & TCBF_SUPOK) &&
	    SEQCMP(ptcp->tcp_ack, ptcb->tcb_supseq) >= 0)
	ptcb->tcb_sbstart = (ptcb->tcb_sbstart+acked) % ptcb->tcb_sbsize;
	ptcb->tcb_sbcount -= acked;
	if (acked) {
		disable(ps);
		if (scount(ptcb->tcb_ssema) <= 0)
			signal(ptcb->tcb_ssema);
		restore(ps);
	}
	tcpostate(ptcb, acked+cacked);
	return acked;
}
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