if_spppsubr.c

基于组件方式开发操作系统的OSKIT源代码

void sppp_attach (struct ifnet *ifp)
{
	struct sppp *sp = (struct sppp*) ifp;

	/* Initialize keepalive handler. */
	if (! spppq)
		timeout (sppp_keepalive, 0, hz * 10);

	/* Insert new entry into the keepalive list. */
	sp->pp_next = spppq;
	spppq = sp;

	sp->pp_if.if_type = IFT_PPP;
	sp->pp_if.if_output = sppp_output;
	sp->pp_fastq.ifq_maxlen = 32;
	sp->pp_loopcnt = 0;
	sp->pp_alivecnt = 0;
	sp->pp_seq = 0;
	sp->pp_rseq = 0;
	sp->lcp.magic = 0;
	sp->lcp.state = LCP_STATE_CLOSED;
	sp->ipcp.state = IPCP_STATE_CLOSED;
}

void sppp_detach (struct ifnet *ifp)
{
	struct sppp **q, *p, *sp = (struct sppp*) ifp;

	/* Remove the entry from the keepalive list. */
	for (q = &spppq; (p = *q); q = &p->pp_next)
		if (p == sp) {
			*q = p->pp_next;
			break;
		}

	/* Stop keepalive handler. */
	if (! spppq)
		untimeout (sppp_keepalive, 0);
	UNTIMO (sp);
}

/*
 * Flush the interface output queue.
 */
void sppp_flush (struct ifnet *ifp)
{
	struct sppp *sp = (struct sppp*) ifp;

	qflush (&sp->pp_if.if_snd);
	qflush (&sp->pp_fastq);
}

/*
 * Check if the output queue is empty.
 */
int sppp_isempty (struct ifnet *ifp)
{
	struct sppp *sp = (struct sppp*) ifp;
	int empty, s = splimp ();

	empty = !sp->pp_fastq.ifq_head && !sp->pp_if.if_snd.ifq_head;
	splx (s);
	return (empty);
}

/*
 * Get next packet to send.
 */
struct mbuf *sppp_dequeue (struct ifnet *ifp)
{
	struct sppp *sp = (struct sppp*) ifp;
	struct mbuf *m;
	int s = splimp ();

	IF_DEQUEUE (&sp->pp_fastq, m);
	if (! m)
		IF_DEQUEUE (&sp->pp_if.if_snd, m);
	splx (s);
	return (m);
}

/*
 * Send keepalive packets, every 10 seconds.
 */
void sppp_keepalive (void *dummy)
{
	struct sppp *sp;
	int s = splimp ();

	for (sp=spppq; sp; sp=sp->pp_next) {
		struct ifnet *ifp = &sp->pp_if;

		/* Keepalive mode disabled or channel down? */
		if (! (sp->pp_flags & PP_KEEPALIVE) ||
		    ! (ifp->if_flags & IFF_RUNNING))
			continue;

		/* No keepalive in PPP mode if LCP not opened yet. */
		if (! (sp->pp_flags & PP_CISCO) &&
		    sp->lcp.state != LCP_STATE_OPENED)
			continue;

		if (sp->pp_alivecnt == MAXALIVECNT) {
			/* No keepalive packets got.  Stop the interface. */
			printf ("%s%d: down\n", ifp->if_name, ifp->if_unit);
			if_down (ifp);
			qflush (&sp->pp_fastq);
			if (! (sp->pp_flags & PP_CISCO)) {
				/* Shut down the PPP link. */
				sp->lcp.state = LCP_STATE_CLOSED;
				sp->ipcp.state = IPCP_STATE_CLOSED;
				UNTIMO (sp);
				/* Initiate negotiation. */
				sppp_lcp_open (sp);
			}
		}
		if (sp->pp_alivecnt <= MAXALIVECNT)
			++sp->pp_alivecnt;
		if (sp->pp_flags & PP_CISCO)
			sppp_cisco_send (sp, CISCO_KEEPALIVE_REQ, ++sp->pp_seq,
				sp->pp_rseq);
		else if (sp->lcp.state == LCP_STATE_OPENED) {
			long nmagic = htonl (sp->lcp.magic);
			sp->lcp.echoid = ++sp->pp_seq;
			sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REQ,
				sp->lcp.echoid, 4, &nmagic);
		}
	}
	splx (s);
	timeout (sppp_keepalive, 0, hz * 10);
}

/*
 * Handle incoming PPP Link Control Protocol packets.
 */
void sppp_lcp_input (struct sppp *sp, struct mbuf *m)
{
	struct lcp_header *h;
	struct ifnet *ifp = &sp->pp_if;
	int len = m->m_pkthdr.len;
	u_char *p, opt[6];
	u_long rmagic;

	if (len < 4) {
		if (ifp->if_flags & IFF_DEBUG)
			printf ("%s%d: invalid lcp packet length: %d bytes\n",
				ifp->if_name, ifp->if_unit, len);
		return;
	}
	h = mtod (m, struct lcp_header*);
	if (ifp->if_flags & IFF_DEBUG) {
		char state = '?';
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:   state = 'C'; break;
		case LCP_STATE_ACK_RCVD: state = 'R'; break;
		case LCP_STATE_ACK_SENT: state = 'S'; break;
		case LCP_STATE_OPENED:   state = 'O'; break;
		}
		printf ("%s%d: lcp input(%c): %d bytes <%s id=%xh len=%xh",
			ifp->if_name, ifp->if_unit, state, len,
			sppp_lcp_type_name (h->type), h->ident, ntohs (h->len));
		if (len > 4)
			sppp_print_bytes ((u_char*) (h+1), len-4);
		printf (">\n");
	}
	if (len > ntohs (h->len))
		len = ntohs (h->len);
	switch (h->type) {
	default:
		/* Unknown packet type -- send Code-Reject packet. */
		sppp_cp_send (sp, PPP_LCP, LCP_CODE_REJ, ++sp->pp_seq,
			m->m_pkthdr.len, h);
		break;
	case LCP_CONF_REQ:
		if (len < 4) {
			if (ifp->if_flags & IFF_DEBUG)
				printf ("%s%d: invalid lcp configure request packet length: %d bytes\n",
					ifp->if_name, ifp->if_unit, len);
			break;
		}
		if (len>4 && !sppp_lcp_conf_parse_options (sp, h, len, &rmagic))
			goto badreq;
		if (rmagic == sp->lcp.magic) {
			/* Local and remote magics equal -- loopback? */
			if (sp->pp_loopcnt >= MAXALIVECNT*5) {
				printf ("%s%d: loopback\n",
					ifp->if_name, ifp->if_unit);
				sp->pp_loopcnt = 0;
				if (ifp->if_flags & IFF_UP) {
					if_down (ifp);
					qflush (&sp->pp_fastq);
				}
			} else if (ifp->if_flags & IFF_DEBUG)
				printf ("%s%d: conf req: magic glitch\n",
					ifp->if_name, ifp->if_unit);
			++sp->pp_loopcnt;

			/* MUST send Conf-Nack packet. */
			rmagic = ~sp->lcp.magic;
			opt[0] = LCP_OPT_MAGIC;
			opt[1] = sizeof (opt);
			opt[2] = rmagic >> 24;
			opt[3] = rmagic >> 16;
			opt[4] = rmagic >> 8;
			opt[5] = rmagic;
			sppp_cp_send (sp, PPP_LCP, LCP_CONF_NAK,
				h->ident, sizeof (opt), &opt);
badreq:
			switch (sp->lcp.state) {
			case LCP_STATE_OPENED:
				/* Initiate renegotiation. */
				sppp_lcp_open (sp);
				/* fall through... */
			case LCP_STATE_ACK_SENT:
				/* Go to closed state. */
				sp->lcp.state = LCP_STATE_CLOSED;
				sp->ipcp.state = IPCP_STATE_CLOSED;
			}
			break;
				}
				/* Send Configure-Ack packet. */
				sp->pp_loopcnt = 0;
				sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
					h->ident, len-4, h+1);
				/* Change the state. */
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:
			sp->lcp.state = LCP_STATE_ACK_SENT;
			break;
		case LCP_STATE_ACK_RCVD:
					sp->lcp.state = LCP_STATE_OPENED;
					sppp_ipcp_open (sp);
			break;
		case LCP_STATE_OPENED:
			/* Remote magic changed -- close session. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
			/* Initiate renegotiation. */
			sppp_lcp_open (sp);
			/* An ACK has already been sent. */
			sp->lcp.state = LCP_STATE_ACK_SENT;
			break;
		}
		break;
	case LCP_CONF_ACK:
		if (h->ident != sp->lcp.confid)
			break;
		UNTIMO (sp);
		if (! (ifp->if_flags & IFF_UP) &&
		    (ifp->if_flags & IFF_RUNNING)) {
			/* Coming out of loopback mode. */
			ifp->if_flags |= IFF_UP;
			printf ("%s%d: up\n", ifp->if_name, ifp->if_unit);
		}
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:
			sp->lcp.state = LCP_STATE_ACK_RCVD;
			TIMO (sp, 5);
			break;
		case LCP_STATE_ACK_SENT:
			sp->lcp.state = LCP_STATE_OPENED;
			sppp_ipcp_open (sp);
			break;
		}
		break;
	case LCP_CONF_NAK:
		if (h->ident != sp->lcp.confid)
			break;
		p = (u_char*) (h+1);
		if (len>=10 && p[0] == LCP_OPT_MAGIC && p[1] >= 4) {
			rmagic = (u_long)p[2] << 24 |
				(u_long)p[3] << 16 | p[4] << 8 | p[5];
			if (rmagic == ~sp->lcp.magic) {
				if (ifp->if_flags & IFF_DEBUG)
					printf ("%s%d: conf nak: magic glitch\n",
						ifp->if_name, ifp->if_unit);
				sp->lcp.magic += time.tv_sec + time.tv_usec;
			} else
				sp->lcp.magic = rmagic;
			}
		if (sp->lcp.state != LCP_STATE_ACK_SENT) {
			/* Go to closed state. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
		}
		/* The link will be renegotiated after timeout,
		 * to avoid endless req-nack loop. */
		UNTIMO (sp);
		TIMO (sp, 2);
		break;
	case LCP_CONF_REJ:
		if (h->ident != sp->lcp.confid)
			break;
		UNTIMO (sp);
		/* Initiate renegotiation. */
		sppp_lcp_open (sp);
		if (sp->lcp.state != LCP_STATE_ACK_SENT) {
			/* Go to closed state. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
		}
		break;
	case LCP_TERM_REQ:
		UNTIMO (sp);
		/* Send Terminate-Ack packet. */
		sppp_cp_send (sp, PPP_LCP, LCP_TERM_ACK, h->ident, 0, 0);
		/* Go to closed state. */
		sp->lcp.state = LCP_STATE_CLOSED;
		sp->ipcp.state = IPCP_STATE_CLOSED;
			/* Initiate renegotiation. */
			sppp_lcp_open (sp);
		break;
	case LCP_TERM_ACK:
	case LCP_CODE_REJ:
	case LCP_PROTO_REJ:
		/* Ignore for now. */
		break;
	case LCP_DISC_REQ:
		/* Discard the packet. */
		break;
	case LCP_ECHO_REQ:
		if (sp->lcp.state != LCP_STATE_OPENED)
			break;
		if (len < 8) {
			if (ifp->if_flags & IFF_DEBUG)
				printf ("%s%d: invalid lcp echo request packet length: %d bytes\n",
					ifp->if_name, ifp->if_unit, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) == sp->lcp.magic) {
			/* Line loopback mode detected. */
			printf ("%s%d: loopback\n", ifp->if_name, ifp->if_unit);
			if_down (ifp);
			qflush (&sp->pp_fastq);

			/* Shut down the PPP link. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
			UNTIMO (sp);
			/* Initiate negotiation. */
			sppp_lcp_open (sp);
			break;
		}
		*(long*)(h+1) = htonl (sp->lcp.magic);
		sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REPLY, h->ident, len-4, h+1);
		break;
	case LCP_ECHO_REPLY:
		if (h->ident != sp->lcp.echoid)
			break;
		if (len < 8) {
			if (ifp->if_flags & IFF_DEBUG)
				printf ("%s%d: invalid lcp echo reply packet length: %d bytes\n",
					ifp->if_name, ifp->if_unit, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) != sp->lcp.magic)
		sp->pp_alivecnt = 0;
		break;
	}
}

/*
 * Handle incoming Cisco keepalive protocol packets.
 */
void sppp_cisco_input (struct sppp *sp, struct mbuf *m)
{
	struct cisco_packet *h;
	struct ifaddr *ifa;
	struct ifnet *ifp = &sp->pp_if;

	if (m->m_pkthdr.len != CISCO_PACKET_LEN) {
		if (ifp->if_flags & IFF_DEBUG)
			printf ("%s%d: invalid cisco packet length: %d bytes\n",
				ifp->if_name, ifp->if_unit, m->m_pkthdr.len);
		return;
	}
	h = mtod (m, struct cisco_packet*);
	if (ifp->if_flags & IFF_DEBUG)
		printf ("%s%d: cisco input: %d bytes <%lxh %lxh %lxh %xh %xh-%xh>\n",
			ifp->if_name, ifp->if_unit, m->m_pkthdr.len,
			ntohl (h->type), h->par1, h->par2, h->rel,
			h->time0, h->time1);
	switch (ntohl (h->type)) {
	default:
		if (ifp->if_flags & IFF_DEBUG)
			printf ("%s%d: unknown cisco packet type: 0x%lx\n",
				ifp->if_name, ifp->if_unit, ntohl (h->type));
		break;
	case CISCO_ADDR_REPLY:
		/* Reply on address request, ignore */
		break;
	case CISCO_KEEPALIVE_REQ:
		sp->pp_alivecnt = 0;
		sp->pp_rseq = ntohl (h->par1);
		if (sp->pp_seq == sp->pp_rseq) {
			/* Local and remote sequence numbers are equal.
			 * Probably, the line is in loopback mode. */
			if (sp->pp_loopcnt >= MAXALIVECNT) {
				printf ("%s%d: loopback\n",
					ifp->if_name, ifp->if_unit);
				sp->pp_loopcnt = 0;
				if (ifp->if_flags & IFF_UP) {
					if_down (ifp);
					qflush (&sp->pp_fastq);
				}
			}
			++sp->pp_loopcnt;

			/* Generate new local sequence number */
			sp->pp_seq ^= time.tv_sec ^ time.tv_usec;
			break;
		}
			sp->pp_loopcnt = 0;
		if (! (ifp->if_flags & IFF_UP) &&
		    (ifp->if_flags & IFF_RUNNING)) {
			ifp->if_flags |= IFF_UP;
			printf ("%s%d: up\n", ifp->if_name, ifp->if_unit);
		}
		break;
	case CISCO_ADDR_REQ:
		for (ifa=ifp->if_addrlist; ifa; ifa=ifa->ifa_next)
			if (ifa->ifa_addr->sa_family == AF_INET)
				break;
		if (! ifa) {
			if (ifp->if_flags & IFF_DEBUG)
				printf ("%s%d: unknown address for cisco request\n",
					ifp->if_name, ifp->if_unit);
			return;
		}
		sppp_cisco_send (sp, CISCO_ADDR_REPLY,
			ntohl (((struct sockaddr_in*)ifa->ifa_addr)->sin_addr.s_addr),
			ntohl (((struct sockaddr_in*)ifa->ifa_netmask)->sin_addr.s_addr));
		break;
	}
}

/*
 * Send PPP LCP packet.
 */
void sppp_cp_send (struct sppp *sp, u_short proto, u_char type,
	u_char ident, u_short len, void *data)
{