spp_usrreq.c

早期freebsd实现

			mask = SF_HI;
			goto set_head;

		case SO_HEADERS_ON_OUTPUT:
			mask = SF_HO;
		set_head:
			if (cb->s_flags & SF_PI) {
				ok = mtod(*value, int *);
				if (*ok)
					cb->s_flags |= mask;
				else
					cb->s_flags &= ~mask;
			} else error = EINVAL;
			break;

		case SO_MTU:
			cb->s_mtu = *(mtod(*value, u_short *));
			break;

#ifdef SF_NEWCALL
		case SO_NEWCALL:
			ok = mtod(*value, int *);
			if (*ok) {
				cb->s_flags2 |= SF_NEWCALL;
				spp_newchecks[5]++;
			} else {
				cb->s_flags2 &= ~SF_NEWCALL;
				spp_newchecks[6]++;
			}
			break;
#endif

		case SO_DEFAULT_HEADERS:
			{
				register struct sphdr *sp
						= mtod(*value, struct sphdr *);
				cb->s_dt = sp->sp_dt;
				cb->s_cc = sp->sp_cc & SP_EM;
			}
			break;

		default:
			error = EINVAL;
		}
		m_freem(*value);
		break;
	}
	release:
		return (error);
}

/*ARGSUSED*/
spp_usrreq(so, req, m, nam, controlp)
	struct socket *so;
	int req;
	struct mbuf *m, *nam, *controlp;
{
	struct nspcb *nsp = sotonspcb(so);
	register struct sppcb *cb;
	int s = splnet();
	int error = 0, ostate;
	struct mbuf *mm;
	register struct sockbuf *sb;

	if (req == PRU_CONTROL)
                return (ns_control(so, (int)m, (caddr_t)nam,
			(struct ifnet *)controlp));
	if (nsp == NULL) {
		if (req != PRU_ATTACH) {
			error = EINVAL;
			goto release;
		}
	} else
		cb = nstosppcb(nsp);

	ostate = cb ? cb->s_state : 0;

	switch (req) {

	case PRU_ATTACH:
		if (nsp != NULL) {
			error = EISCONN;
			break;
		}
		error = ns_pcballoc(so, &nspcb);
		if (error)
			break;
		if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
			error = soreserve(so, (u_long) 3072, (u_long) 3072);
			if (error)
				break;
		}
		nsp = sotonspcb(so);

		mm = m_getclr(M_DONTWAIT, MT_PCB);
		sb = &so->so_snd;

		if (mm == NULL) {
			error = ENOBUFS;
			break;
		}
		cb = mtod(mm, struct sppcb *);
		mm = m_getclr(M_DONTWAIT, MT_HEADER);
		if (mm == NULL) {
			(void) m_free(dtom(m));
			error = ENOBUFS;
			break;
		}
		cb->s_idp = mtod(mm, struct idp *);
		cb->s_state = TCPS_LISTEN;
		cb->s_smax = -1;
		cb->s_swl1 = -1;
		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
		cb->s_nspcb = nsp;
		cb->s_mtu = 576 - sizeof (struct spidp);
		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
		cb->s_ssthresh = cb->s_cwnd;
		cb->s_cwmx = sbspace(sb) * CUNIT /
				(2 * sizeof (struct spidp));
		/* Above is recomputed when connecting to account
		   for changed buffering or mtu's */
		cb->s_rtt = SPPTV_SRTTBASE;
		cb->s_rttvar = SPPTV_SRTTDFLT << 2;
		SPPT_RANGESET(cb->s_rxtcur,
		    ((SPPTV_SRTTBASE >> 2) + (SPPTV_SRTTDFLT << 2)) >> 1,
		    SPPTV_MIN, SPPTV_REXMTMAX);
		nsp->nsp_pcb = (caddr_t) cb; 
		break;

	case PRU_DETACH:
		if (nsp == NULL) {
			error = ENOTCONN;
			break;
		}
		if (cb->s_state > TCPS_LISTEN)
			cb = spp_disconnect(cb);
		else
			cb = spp_close(cb);
		break;

	case PRU_BIND:
		error = ns_pcbbind(nsp, nam);
		break;

	case PRU_LISTEN:
		if (nsp->nsp_lport == 0)
			error = ns_pcbbind(nsp, (struct mbuf *)0);
		if (error == 0)
			cb->s_state = TCPS_LISTEN;
		break;

	/*
	 * Initiate connection to peer.
	 * Enter SYN_SENT state, and mark socket as connecting.
	 * Start keep-alive timer, setup prototype header,
	 * Send initial system packet requesting connection.
	 */
	case PRU_CONNECT:
		if (nsp->nsp_lport == 0) {
			error = ns_pcbbind(nsp, (struct mbuf *)0);
			if (error)
				break;
		}
		error = ns_pcbconnect(nsp, nam);
		if (error)
			break;
		soisconnecting(so);
		sppstat.spps_connattempt++;
		cb->s_state = TCPS_SYN_SENT;
		cb->s_did = 0;
		spp_template(cb);
		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
		cb->s_force = 1 + SPPTV_KEEP;
		/*
		 * Other party is required to respond to
		 * the port I send from, but he is not
		 * required to answer from where I am sending to,
		 * so allow wildcarding.
		 * original port I am sending to is still saved in
		 * cb->s_dport.
		 */
		nsp->nsp_fport = 0;
		error = spp_output(cb, (struct mbuf *) 0);
		break;

	case PRU_CONNECT2:
		error = EOPNOTSUPP;
		break;

	/*
	 * We may decide later to implement connection closing
	 * handshaking at the spp level optionally.
	 * here is the hook to do it:
	 */
	case PRU_DISCONNECT:
		cb = spp_disconnect(cb);
		break;

	/*
	 * Accept a connection.  Essentially all the work is
	 * done at higher levels; just return the address
	 * of the peer, storing through addr.
	 */
	case PRU_ACCEPT: {
		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);

		nam->m_len = sizeof (struct sockaddr_ns);
		sns->sns_family = AF_NS;
		sns->sns_addr = nsp->nsp_faddr;
		break;
		}

	case PRU_SHUTDOWN:
		socantsendmore(so);
		cb = spp_usrclosed(cb);
		if (cb)
			error = spp_output(cb, (struct mbuf *) 0);
		break;

	/*
	 * After a receive, possibly send acknowledgment
	 * updating allocation.
	 */
	case PRU_RCVD:
		cb->s_flags |= SF_RVD;
		(void) spp_output(cb, (struct mbuf *) 0);
		cb->s_flags &= ~SF_RVD;
		break;

	case PRU_ABORT:
		(void) spp_drop(cb, ECONNABORTED);
		break;

	case PRU_SENSE:
	case PRU_CONTROL:
		m = NULL;
		error = EOPNOTSUPP;
		break;

	case PRU_RCVOOB:
		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
		    (so->so_state & SS_RCVATMARK)) {
			m->m_len = 1;
			*mtod(m, caddr_t) = cb->s_iobc;
			break;
		}
		error = EINVAL;
		break;

	case PRU_SENDOOB:
		if (sbspace(&so->so_snd) < -512) {
			error = ENOBUFS;
			break;
		}
		cb->s_oobflags |= SF_SOOB;
		/* fall into */
	case PRU_SEND:
		if (controlp) {
			u_short *p = mtod(controlp, u_short *);
			spp_newchecks[2]++;
			if ((p[0] == 5) && p[1] == 1) { /* XXXX, for testing */
				cb->s_shdr.sp_dt = *(u_char *)(&p[2]);
				spp_newchecks[3]++;
			}
			m_freem(controlp);
		}
		controlp = NULL;
		error = spp_output(cb, m);
		m = NULL;
		break;

	case PRU_SOCKADDR:
		ns_setsockaddr(nsp, nam);
		break;

	case PRU_PEERADDR:
		ns_setpeeraddr(nsp, nam);
		break;

	case PRU_SLOWTIMO:
		cb = spp_timers(cb, (int)nam);
		req |= ((int)nam) << 8;
		break;

	case PRU_FASTTIMO:
	case PRU_PROTORCV:
	case PRU_PROTOSEND:
		error =  EOPNOTSUPP;
		break;

	default:
		panic("sp_usrreq");
	}
	if (cb && (so->so_options & SO_DEBUG || traceallspps))
		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
release:
	if (controlp != NULL)
		m_freem(controlp);
	if (m != NULL)
		m_freem(m);
	splx(s);
	return (error);
}

spp_usrreq_sp(so, req, m, nam, controlp)
	struct socket *so;
	int req;
	struct mbuf *m, *nam, *controlp;
{
	int error = spp_usrreq(so, req, m, nam, controlp);

	if (req == PRU_ATTACH && error == 0) {
		struct nspcb *nsp = sotonspcb(so);
		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
					(SF_HI | SF_HO | SF_PI);
	}
	return (error);
}

/*
 * Create template to be used to send spp packets on a connection.
 * Called after host entry created, fills
 * in a skeletal spp header (choosing connection id),
 * minimizing the amount of work necessary when the connection is used.
 */
spp_template(cb)
	register struct sppcb *cb;
{
	register struct nspcb *nsp = cb->s_nspcb;
	register struct idp *idp = cb->s_idp;
	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);

	idp->idp_pt = NSPROTO_SPP;
	idp->idp_sna = nsp->nsp_laddr;
	idp->idp_dna = nsp->nsp_faddr;
	cb->s_sid = htons(spp_iss);
	spp_iss += SPP_ISSINCR/2;
	cb->s_alo = 1;
	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
					of large packets */
	cb->s_cwmx = (sbspace(sb) * CUNIT) / (2 * sizeof(struct spidp));
	cb->s_cwmx = max(cb->s_cwmx, cb->s_cwnd);
		/* But allow for lots of little packets as well */
}

/*
 * Close a SPIP control block:
 *	discard spp control block itself
 *	discard ns protocol control block
 *	wake up any sleepers
 */
struct sppcb *
spp_close(cb)
	register struct sppcb *cb;
{
	register struct spidp_q *s;
	struct nspcb *nsp = cb->s_nspcb;
	struct socket *so = nsp->nsp_socket;
	register struct mbuf *m;

	s = cb->s_q.si_next;
	while (s != &(cb->s_q)) {
		s = s->si_next;
		m = dtom(s->si_prev);
		remque(s->si_prev);
		m_freem(m);
	}
	(void) m_free(dtom(cb->s_idp));
	(void) m_free(dtom(cb));
	nsp->nsp_pcb = 0;
	soisdisconnected(so);
	ns_pcbdetach(nsp);
	sppstat.spps_closed++;
	return ((struct sppcb *)0);
}
/*
 *	Someday we may do level 3 handshaking
 *	to close a connection or send a xerox style error.
 *	For now, just close.
 */
struct sppcb *
spp_usrclosed(cb)
	register struct sppcb *cb;
{
	return (spp_close(cb));
}
struct sppcb *
spp_disconnect(cb)
	register struct sppcb *cb;
{
	return (spp_close(cb));
}
/*
 * Drop connection, reporting
 * the specified error.
 */
struct sppcb *
spp_drop(cb, errno)
	register struct sppcb *cb;
	int errno;
{
	struct socket *so = cb->s_nspcb->nsp_socket;

	/*
	 * someday, in the xerox world
	 * we will generate error protocol packets
	 * announcing that the socket has gone away.
	 */
	if (TCPS_HAVERCVDSYN(cb->s_state)) {
		sppstat.spps_drops++;
		cb->s_state = TCPS_CLOSED;
		/*(void) tcp_output(cb);*/
	} else
		sppstat.spps_conndrops++;
	so->so_error = errno;
	return (spp_close(cb));
}

spp_abort(nsp)
	struct nspcb *nsp;
{

	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
}

int	spp_backoff[SPP_MAXRXTSHIFT+1] =
    { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
/*
 * Fast timeout routine for processing delayed acks
 */
spp_fasttimo()
{
	register struct nspcb *nsp;
	register struct sppcb *cb;
	int s = splnet();

	nsp = nspcb.nsp_next;
	if (nsp)
	for (; nsp != &nspcb; nsp = nsp->nsp_next)
		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
		    (cb->s_flags & SF_DELACK)) {
			cb->s_flags &= ~SF_DELACK;
			cb->s_flags |= SF_ACKNOW;
			sppstat.spps_delack++;
			(void) spp_output(cb, (struct mbuf *) 0);
		}
	splx(s);
}

/*
 * spp protocol timeout routine called every 500 ms.
 * Updates the timers in all active pcb's and
 * causes finite state machine actions if timers expire.
 */
spp_slowtimo()
{
	register struct nspcb *ip, *ipnxt;
	register struct sppcb *cb;
	int s = splnet();
	register int i;

	/*
	 * Search through tcb's and update active timers.
	 */
	ip = nspcb.nsp_next;
	if (ip == 0) {
		splx(s);
		return;
	}
	while (ip != &nspcb) {
		cb = nstosppcb(ip);
		ipnxt = ip->nsp_next;
		if (cb == 0)
			goto tpgone;
		for (i = 0; i < SPPT_NTIMERS; i++) {
			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
				    PRU_SLOWTIMO, (struct mbuf *)0,
				    (struct mbuf *)i, (struct mbuf *)0,
				    (struct mbuf *)0);
				if (ipnxt->nsp_prev != ip)
					goto tpgone;
			}
		}
		cb->s_idle++;
		if (cb->s_rtt)
			cb->s_rtt++;
tpgone:
		ip = ipnxt;
	}
	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
	splx(s);
}
/*
 * SPP timer processing.
 */
struct sppcb *
spp_timers(cb, timer)
	register struct sppcb *cb;
	int timer;
{
	long rexmt;
	int win;

	cb->s_force = 1 + timer;
	switch (timer) {

	/*
	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
	 * control block.
	 */
	case SPPT_2MSL:
		printf("spp: SPPT_2MSL went off for no reason\n");
		cb->s_timer[timer] = 0;
		break;

	/*
	 * Retransmission timer went off.  Message has not
	 * been acked within retransmit interval.  Back off
	 * to a longer retransmit interval and retransmit one packet.
	 */
	case SPPT_REXMT:
		if (++cb->s_rxtshift > SPP_MAXRXTSHIFT) {
			cb->s_rxtshift = SPP_MAXRXTSHIFT;
			sppstat.spps_timeoutdrop++;
			cb = spp_drop(cb, ETIMEDOUT);
			break;
		}
		sppstat.spps_rexmttimeo++;
		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
		rexmt *= spp_backoff[cb->s_rxtshift];
		SPPT_RANGESET(cb->s_rxtcur, rexmt, SPPTV_MIN, SPPTV_REXMTMAX);
		cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
		/*
		 * If we have backed off fairly far, our srtt
		 * estimate is probably bogus.  Clobber it
		 * so we'll take the next rtt measurement as our srtt;
		 * move the current srtt into rttvar to keep the current
		 * retransmit times until then.
		 */
		if (cb->s_rxtshift > SPP_MAXRXTSHIFT / 4 ) {
			cb->s_rttvar += (cb->s_srtt >> 2);
			cb->s_srtt = 0;
		}
		cb->s_snxt = cb->s_rack;
		/*
		 * If timing a packet, stop the timer.
		 */
		cb->s_rtt = 0;
		/*
		 * See very long discussion in tcp_timer.c about congestion
		 * window and sstrhesh
		 */
		win = min(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
		if (win < 2)
			win = 2;
		cb->s_cwnd = CUNIT;
		cb->s_ssthresh = win * CUNIT;
		(void) spp_output(cb, (struct mbuf *) 0);
		break;

	/*
	 * Persistance timer into zero window.
	 * Force a probe to be sent.
	 */
	case SPPT_PERSIST:
		sppstat.spps_persisttimeo++;
		spp_setpersist(cb);
		(void) spp_output(cb, (struct mbuf *) 0);
		break;

	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */
	case SPPT_KEEP:
		sppstat.spps_keeptimeo++;
		if (cb->s_state < TCPS_ESTABLISHED)
			goto dropit;
		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
		    	if (cb->s_idle >= SPPTV_MAXIDLE)
				goto dropit;
			sppstat.spps_keepprobe++;
			(void) spp_output(cb, (struct mbuf *) 0);
		} else
			cb->s_idle = 0;
		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
		break;
	dropit:
		sppstat.spps_keepdrops++;
		cb = spp_drop(cb, ETIMEDOUT);
		break;
	}
	return (cb);
}
#ifndef lint
int SppcbSize = sizeof (struct sppcb);
int NspcbSize = sizeof (struct nspcb);
#endif /* lint */