syncppp.c

linux-2.6.15.6

			sppp_print_bytes ((u8*) (h+1), len-4);
		printk (">\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,
			skb->len, h);
		break;
	case LCP_CONF_REQ:
		if (len < 4) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_DEBUG"%s: invalid lcp configure request packet length: %d bytes\n",
					dev->name, 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) {
				printk (KERN_WARNING "%s: loopback\n",
					dev->name);
				sp->pp_loopcnt = 0;
				if (dev->flags & IFF_UP) {
					if_down (dev);
				}
			} else if (sp->pp_flags & PP_DEBUG)
				printk (KERN_DEBUG "%s: conf req: magic glitch\n",
					dev->name);
			++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;
		if (sp->lcp.state != LCP_STATE_OPENED) {
			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);
			/* Send ACK after our REQ in attempt to break loop */
			sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
					h->ident, len-4, h+1);
			sp->lcp.state = LCP_STATE_ACK_SENT;
			break;
		}
		break;
	case LCP_CONF_ACK:
		if (h->ident != sp->lcp.confid)
			break;
		sppp_clear_timeout (sp);
		if ((sp->pp_link_state != SPPP_LINK_UP) &&
		    (dev->flags & IFF_UP)) {
			/* Coming out of loopback mode. */
			sp->pp_link_state=SPPP_LINK_UP;
			printk (KERN_INFO "%s: protocol up\n", dev->name);
		}
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:
			sp->lcp.state = LCP_STATE_ACK_RCVD;
			sppp_set_timeout (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 = (u8*) (h+1);
		if (len>=10 && p[0] == LCP_OPT_MAGIC && p[1] >= 4) {
			rmagic = (u32)p[2] << 24 |
				(u32)p[3] << 16 | p[4] << 8 | p[5];
			if (rmagic == ~sp->lcp.magic) {
				int newmagic;
				if (sp->pp_flags & PP_DEBUG)
					printk (KERN_DEBUG "%s: conf nak: magic glitch\n",
						dev->name);
				get_random_bytes(&newmagic, sizeof(newmagic));
				sp->lcp.magic += newmagic;
			} 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. */
		sppp_clear_timeout (sp);
		sppp_set_timeout (sp, 2);
		break;
	case LCP_CONF_REJ:
		if (h->ident != sp->lcp.confid)
			break;
		sppp_clear_timeout (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:
		sppp_clear_timeout (sp);
		/* Send Terminate-Ack packet. */
		sppp_cp_send (sp, PPP_LCP, LCP_TERM_ACK, h->ident, 0, NULL);
		/* 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 (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid lcp echo request packet length: %d bytes\n",
					dev->name, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) == sp->lcp.magic) {
			/* Line loopback mode detected. */
			printk (KERN_WARNING "%s: loopback\n", dev->name);
			if_down (dev);

			/* Shut down the PPP link. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
			sppp_clear_timeout (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 (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid lcp echo reply packet length: %d bytes\n",
					dev->name, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) != sp->lcp.magic)
		sp->pp_alivecnt = 0;
		break;
	}
}

/*
 * Handle incoming Cisco keepalive protocol packets.
 */

static void sppp_cisco_input (struct sppp *sp, struct sk_buff *skb)
{
	struct cisco_packet *h;
	struct net_device *dev = sp->pp_if;

	if (!pskb_may_pull(skb, sizeof(struct cisco_packet))
	    || (skb->len != CISCO_PACKET_LEN
		&& skb->len != CISCO_BIG_PACKET_LEN)) {
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: invalid cisco packet length: %d bytes\n",
				dev->name,  skb->len);
		return;
	}
	h = (struct cisco_packet *)skb->data;
	skb_pull(skb, sizeof(struct cisco_packet*));
	if (sp->pp_flags & PP_DEBUG)
		printk (KERN_WARNING "%s: cisco input: %d bytes <%xh %xh %xh %xh %xh-%xh>\n",
			dev->name,  skb->len,
			ntohl (h->type), h->par1, h->par2, h->rel,
			h->time0, h->time1);
	switch (ntohl (h->type)) {
	default:
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: unknown cisco packet type: 0x%x\n",
				dev->name,  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. */
			int newseq;
			if (sp->pp_loopcnt >= MAXALIVECNT) {
				printk (KERN_WARNING "%s: loopback\n",
					dev->name);
				sp->pp_loopcnt = 0;
				if (dev->flags & IFF_UP) {
					if_down (dev);
				}
			}
			++sp->pp_loopcnt;

			/* Generate new local sequence number */
			get_random_bytes(&newseq, sizeof(newseq));
			sp->pp_seq ^= newseq;
			break;
		}
		sp->pp_loopcnt = 0;
		if (sp->pp_link_state==SPPP_LINK_DOWN &&
		    (dev->flags & IFF_UP)) {
			sp->pp_link_state=SPPP_LINK_UP;
			printk (KERN_INFO "%s: protocol up\n", dev->name);
		}
		break;
	case CISCO_ADDR_REQ:
		/* Stolen from net/ipv4/devinet.c -- SIOCGIFADDR ioctl */
		{
		struct in_device *in_dev;
		struct in_ifaddr *ifa;
		u32 addr = 0, mask = ~0; /* FIXME: is the mask correct? */
#ifdef CONFIG_INET
		rcu_read_lock();
		if ((in_dev = __in_dev_get_rcu(dev)) != NULL)
		{
			for (ifa=in_dev->ifa_list; ifa != NULL;
				ifa=ifa->ifa_next) {
				if (strcmp(dev->name, ifa->ifa_label) == 0) 
				{
					addr = ifa->ifa_local;
					mask = ifa->ifa_mask;
					break;
				}
			}
		}
		rcu_read_unlock();
#endif		
		/* I hope both addr and mask are in the net order */
		sppp_cisco_send (sp, CISCO_ADDR_REPLY, addr, mask);
		break;
		}
	}
}


/*
 * Send PPP LCP packet.
 */

static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
	u8 ident, u16 len, void *data)
{
	struct ppp_header *h;
	struct lcp_header *lh;
	struct sk_buff *skb;
	struct net_device *dev = sp->pp_if;

	skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+LCP_HEADER_LEN+len,
		GFP_ATOMIC);
	if (skb==NULL)
		return;

	skb_reserve(skb,dev->hard_header_len);
	
	h = (struct ppp_header *)skb_put(skb, sizeof(struct ppp_header));
	h->address = PPP_ALLSTATIONS;        /* broadcast address */
	h->control = PPP_UI;                 /* Unnumbered Info */
	h->protocol = htons (proto);         /* Link Control Protocol */

	lh = (struct lcp_header *)skb_put(skb, sizeof(struct lcp_header));
	lh->type = type;
	lh->ident = ident;
	lh->len = htons (LCP_HEADER_LEN + len);

	if (len)
		memcpy(skb_put(skb,len),data, len);

	if (sp->pp_flags & PP_DEBUG) {
		printk (KERN_WARNING "%s: %s output <%s id=%xh len=%xh",
			dev->name, 
			proto==PPP_LCP ? "lcp" : "ipcp",
			proto==PPP_LCP ? sppp_lcp_type_name (lh->type) :
			sppp_ipcp_type_name (lh->type), lh->ident,
			ntohs (lh->len));
		if (len)
			sppp_print_bytes ((u8*) (lh+1), len);
		printk (">\n");
	}
	sp->obytes += skb->len;
	/* Control is high priority so it doesn't get queued behind data */
	skb->priority=TC_PRIO_CONTROL;
	skb->dev = dev;
	skb_queue_tail(&tx_queue, skb);
}

/*
 * Send Cisco keepalive packet.
 */

static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2)
{
	struct ppp_header *h;
	struct cisco_packet *ch;
	struct sk_buff *skb;
	struct net_device *dev = sp->pp_if;
	u32 t = jiffies * 1000/HZ;

	skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+CISCO_PACKET_LEN,
		GFP_ATOMIC);

	if(skb==NULL)
		return;
		
	skb_reserve(skb, dev->hard_header_len);
	h = (struct ppp_header *)skb_put (skb, sizeof(struct ppp_header));
	h->address = CISCO_MULTICAST;
	h->control = 0;
	h->protocol = htons (CISCO_KEEPALIVE);

	ch = (struct cisco_packet*)skb_put(skb, CISCO_PACKET_LEN);
	ch->type = htonl (type);
	ch->par1 = htonl (par1);
	ch->par2 = htonl (par2);
	ch->rel = -1;
	ch->time0 = htons ((u16) (t >> 16));
	ch->time1 = htons ((u16) t);

	if (sp->pp_flags & PP_DEBUG)
		printk (KERN_WARNING "%s: cisco output: <%xh %xh %xh %xh %xh-%xh>\n",
			dev->name,  ntohl (ch->type), ch->par1,
			ch->par2, ch->rel, ch->time0, ch->time1);
	sp->obytes += skb->len;
	skb->priority=TC_PRIO_CONTROL;
	skb->dev = dev;
	skb_queue_tail(&tx_queue, skb);
}

/**
 *	sppp_close - close down a synchronous PPP or Cisco HDLC link
 *	@dev: The network device to drop the link of
 *
 *	This drops the logical interface to the channel. It is not
 *	done politely as we assume we will also be dropping DTR. Any
 *	timeouts are killed.
 */

int sppp_close (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	spin_lock_irqsave(&sp->lock, flags);
	sp->pp_link_state = SPPP_LINK_DOWN;
	sp->lcp.state = LCP_STATE_CLOSED;
	sp->ipcp.state = IPCP_STATE_CLOSED;
	sppp_clear_timeout (sp);
	spin_unlock_irqrestore(&sp->lock, flags);

	return 0;
}

EXPORT_SYMBOL(sppp_close);

/**
 *	sppp_open - open a synchronous PPP or Cisco HDLC link
 *	@dev:	Network device to activate
 *	
 *	Close down any existing synchronous session and commence
 *	from scratch. In the PPP case this means negotiating LCP/IPCP
 *	and friends, while for Cisco HDLC we simply need to start sending
 *	keepalives
 */

int sppp_open (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	sppp_close(dev);

	spin_lock_irqsave(&sp->lock, flags);
	if (!(sp->pp_flags & PP_CISCO)) {
		sppp_lcp_open (sp);
	}
	sp->pp_link_state = SPPP_LINK_DOWN;
	spin_unlock_irqrestore(&sp->lock, flags);
	sppp_flush_xmit();

	return 0;
}

EXPORT_SYMBOL(sppp_open);

/**
 *	sppp_reopen - notify of physical link loss
 *	@dev: Device that lost the link
 *
 *	This function informs the synchronous protocol code that
 *	the underlying link died (for example a carrier drop on X.21)
 *
 *	We increment the magic numbers to ensure that if the other end
 *	failed to notice we will correctly start a new session. It happens
 *	do to the nature of telco circuits is that you can lose carrier on
 *	one endonly.
 *
 *	Having done this we go back to negotiating. This function may
 *	be called from an interrupt context.
 */
 
int sppp_reopen (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	sppp_close(dev);

	spin_lock_irqsave(&sp->lock, flags);
	if (!(sp->pp_flags & PP_CISCO))
	{
		sp->lcp.magic = jiffies;
		++sp->pp_seq;
		sp->lcp.state = LCP_STATE_CLOSED;
		sp->ipcp.state = IPCP_STATE_CLOSED;
		/* Give it a moment for the line to settle then go */
		sppp_set_timeout (sp, 1);
	} 
	sp->pp_link_state=SPPP_LINK_DOWN;
	spin_unlock_irqrestore(&sp->lock, flags);

	return 0;
}

EXPORT_SYMBOL(sppp_reopen);

/**
 *	sppp_change_mtu - Change the link MTU
 *	@dev:	Device to change MTU on
 *	@new_mtu: New MTU
 *
 *	Change the MTU on the link. This can only be called with
 *	the link down. It returns an error if the link is up or
 *	the mtu is out of range.
 */
 
static int sppp_change_mtu(struct net_device *dev, int new_mtu)
{