isdn_ppp.c

linux-2.6.15.6

		kfree_skb(skb);
		return;
	}
	is = ippp_table[slot];

	if (is->debug & 0x4) {
		printk(KERN_DEBUG "ippp_receive: is:%08lx lp:%08lx slot:%d unit:%d len:%d\n",
		       (long)is,(long)lp,lp->ppp_slot,is->unit,(int) skb->len);
		isdn_ppp_frame_log("receive", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
	}

 	if (isdn_ppp_skip_ac(is, skb) < 0) {
 		kfree_skb(skb);
 		return;
 	}
  	proto = isdn_ppp_strip_proto(skb);
 	if (proto < 0) {
 		kfree_skb(skb);
 		return;
 	}
  
#ifdef CONFIG_ISDN_MPP
 	if (is->compflags & SC_LINK_DECOMP_ON) {
 		skb = isdn_ppp_decompress(skb, is, NULL, &proto);
 		if (!skb) // decompression error
 			return;
 	}
	
 	if (!(is->mpppcfg & SC_REJ_MP_PROT)) { // we agreed to receive MPPP
  		if (proto == PPP_MP) {
  			isdn_ppp_mp_receive(net_dev, lp, skb);
 			return;
 		}
 	} 
#endif
 	isdn_ppp_push_higher(net_dev, lp, skb, proto);
}

/*
 * we receive a reassembled frame, MPPP has been taken care of before.
 * address/control and protocol have been stripped from the skb
 * note: net_dev has to be master net_dev
 */
static void
isdn_ppp_push_higher(isdn_net_dev * net_dev, isdn_net_local * lp, struct sk_buff *skb, int proto)
{
	struct net_device *dev = &net_dev->dev;
 	struct ippp_struct *is, *mis;
	isdn_net_local *mlp = NULL;
	int slot;

	slot = lp->ppp_slot;
	if (slot < 0 || slot >= ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_push_higher: lp->ppp_slot(%d)\n",
			lp->ppp_slot);
		goto drop_packet;
	}
	is = ippp_table[slot];
 	
 	if (lp->master) { // FIXME?
		mlp = (isdn_net_local *) lp->master->priv;
 		slot = mlp->ppp_slot;
 		if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
 			printk(KERN_ERR "isdn_ppp_push_higher: master->ppp_slot(%d)\n",
 				lp->ppp_slot);
			goto drop_packet;
 		}
 	}
 	mis = ippp_table[slot];

	if (is->debug & 0x10) {
		printk(KERN_DEBUG "push, skb %d %04x\n", (int) skb->len, proto);
		isdn_ppp_frame_log("rpush", skb->data, skb->len, 32,is->unit,lp->ppp_slot);
	}
	if (mis->compflags & SC_DECOMP_ON) {
		skb = isdn_ppp_decompress(skb, is, mis, &proto);
		if (!skb) // decompression error
  			return;
  	}
	switch (proto) {
		case PPP_IPX:  /* untested */
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: IPX\n");
			skb->protocol = htons(ETH_P_IPX);
			break;
		case PPP_IP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: IP\n");
			skb->protocol = htons(ETH_P_IP);
			break;
		case PPP_COMP:
		case PPP_COMPFRAG:
			printk(KERN_INFO "isdn_ppp: unexpected compressed frame dropped\n");
			goto drop_packet;
#ifdef CONFIG_ISDN_PPP_VJ
		case PPP_VJC_UNCOMP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: VJC_UNCOMP\n");
			if (net_dev->local->ppp_slot < 0) {
				printk(KERN_ERR "%s: net_dev->local->ppp_slot(%d) out of range\n",
					__FUNCTION__, net_dev->local->ppp_slot);
				goto drop_packet;
			}
			if (slhc_remember(ippp_table[net_dev->local->ppp_slot]->slcomp, skb->data, skb->len) <= 0) {
				printk(KERN_WARNING "isdn_ppp: received illegal VJC_UNCOMP frame!\n");
				goto drop_packet;
			}
			skb->protocol = htons(ETH_P_IP);
			break;
		case PPP_VJC_COMP:
			if (is->debug & 0x20)
				printk(KERN_DEBUG "isdn_ppp: VJC_COMP\n");
			{
				struct sk_buff *skb_old = skb;
				int pkt_len;
				skb = dev_alloc_skb(skb_old->len + 128);

				if (!skb) {
					printk(KERN_WARNING "%s: Memory squeeze, dropping packet.\n", dev->name);
					skb = skb_old;
					goto drop_packet;
				}
				skb_put(skb, skb_old->len + 128);
				memcpy(skb->data, skb_old->data, skb_old->len);
				if (net_dev->local->ppp_slot < 0) {
					printk(KERN_ERR "%s: net_dev->local->ppp_slot(%d) out of range\n",
						__FUNCTION__, net_dev->local->ppp_slot);
					goto drop_packet;
				}
				pkt_len = slhc_uncompress(ippp_table[net_dev->local->ppp_slot]->slcomp,
						skb->data, skb_old->len);
				kfree_skb(skb_old);
				if (pkt_len < 0)
					goto drop_packet;

				skb_trim(skb, pkt_len);
				skb->protocol = htons(ETH_P_IP);
			}
			break;
#endif
		case PPP_CCP:
		case PPP_CCPFRAG:
			isdn_ppp_receive_ccp(net_dev,lp,skb,proto);
			/* Dont pop up ResetReq/Ack stuff to the daemon any
			   longer - the job is done already */
			if(skb->data[0] == CCP_RESETREQ ||
			   skb->data[0] == CCP_RESETACK)
				break;
			/* fall through */
		default:
			isdn_ppp_fill_rq(skb->data, skb->len, proto, lp->ppp_slot);	/* push data to pppd device */
			kfree_skb(skb);
			return;
	}

#ifdef CONFIG_IPPP_FILTER
	/* check if the packet passes the pass and active filters
	 * the filter instructions are constructed assuming
	 * a four-byte PPP header on each packet (which is still present) */
	skb_push(skb, 4);

	{
		u_int16_t *p = (u_int16_t *) skb->data;

		*p = 0;	/* indicate inbound */
	}

	if (is->pass_filter
	    && sk_run_filter(skb, is->pass_filter, is->pass_len) == 0) {
		if (is->debug & 0x2)
			printk(KERN_DEBUG "IPPP: inbound frame filtered.\n");
		kfree_skb(skb);
		return;
	}
	if (!(is->active_filter
	      && sk_run_filter(skb, is->active_filter,
	                       is->active_len) == 0)) {
		if (is->debug & 0x2)
			printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n");
		lp->huptimer = 0;
		if (mlp)
			mlp->huptimer = 0;
	}
	skb_pull(skb, 4);
#else /* CONFIG_IPPP_FILTER */
	lp->huptimer = 0;
	if (mlp)
		mlp->huptimer = 0;
#endif /* CONFIG_IPPP_FILTER */
	skb->dev = dev;
	skb->mac.raw = skb->data;
	netif_rx(skb);
	/* net_dev->local->stats.rx_packets++; done in isdn_net.c */
	return;

 drop_packet:
	net_dev->local->stats.rx_dropped++;
	kfree_skb(skb);
}

/*
 * isdn_ppp_skb_push ..
 * checks whether we have enough space at the beginning of the skb
 * and allocs a new SKB if necessary
 */
static unsigned char *isdn_ppp_skb_push(struct sk_buff **skb_p,int len)
{
	struct sk_buff *skb = *skb_p;

	if(skb_headroom(skb) < len) {
		struct sk_buff *nskb = skb_realloc_headroom(skb, len);

		if (!nskb) {
			printk(KERN_ERR "isdn_ppp_skb_push: can't realloc headroom!\n");
			dev_kfree_skb(skb);
			return NULL;
		}
		printk(KERN_DEBUG "isdn_ppp_skb_push:under %d %d\n",skb_headroom(skb),len);
		dev_kfree_skb(skb);
		*skb_p = nskb;
		return skb_push(nskb, len);
	}
	return skb_push(skb,len);
}

/*
 * send ppp frame .. we expect a PIDCOMPressable proto --
 *  (here: currently always PPP_IP,PPP_VJC_COMP,PPP_VJC_UNCOMP)
 *
 * VJ compression may change skb pointer!!! .. requeue with old
 * skb isn't allowed!!
 */

int
isdn_ppp_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	isdn_net_local *lp,*mlp;
	isdn_net_dev *nd;
	unsigned int proto = PPP_IP;     /* 0x21 */
	struct ippp_struct *ipt,*ipts;
	int slot, retval = 0;

	mlp = (isdn_net_local *) (netdev->priv);
	nd = mlp->netdev;       /* get master lp */

	slot = mlp->ppp_slot;
	if (slot < 0 || slot >= ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_xmit: lp->ppp_slot(%d)\n",
			mlp->ppp_slot);
		kfree_skb(skb);
		goto out;
	}
	ipts = ippp_table[slot];

	if (!(ipts->pppcfg & SC_ENABLE_IP)) {	/* PPP connected ? */
		if (ipts->debug & 0x1)
			printk(KERN_INFO "%s: IP frame delayed.\n", netdev->name);
		retval = 1;
		goto out;
	}

	switch (ntohs(skb->protocol)) {
		case ETH_P_IP:
			proto = PPP_IP;
			break;
		case ETH_P_IPX:
			proto = PPP_IPX;	/* untested */
			break;
		default:
			printk(KERN_ERR "isdn_ppp: skipped unsupported protocol: %#x.\n", 
			       skb->protocol);
			dev_kfree_skb(skb);
			goto out;
	}

	lp = isdn_net_get_locked_lp(nd);
	if (!lp) {
		printk(KERN_WARNING "%s: all channels busy - requeuing!\n", netdev->name);
		retval = 1;
		goto out;
	}
	/* we have our lp locked from now on */

	slot = lp->ppp_slot;
	if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
		printk(KERN_ERR "isdn_ppp_xmit: lp->ppp_slot(%d)\n",
			lp->ppp_slot);
		kfree_skb(skb);
		goto unlock;
	}
	ipt = ippp_table[slot];

	/*
	 * after this line .. requeueing in the device queue is no longer allowed!!!
	 */

	/* Pull off the fake header we stuck on earlier to keep
	 * the fragmentation code happy.
	 */
	skb_pull(skb,IPPP_MAX_HEADER);

#ifdef CONFIG_IPPP_FILTER
	/* check if we should pass this packet
	 * the filter instructions are constructed assuming
	 * a four-byte PPP header on each packet */
	*skb_push(skb, 4) = 1; /* indicate outbound */

	{
		u_int16_t *p = (u_int16_t *) skb->data;

		p++;
		*p   = htons(proto);
	}

	if (ipt->pass_filter
	    && sk_run_filter(skb, ipt->pass_filter, ipt->pass_len) == 0) {
		if (ipt->debug & 0x4)
			printk(KERN_DEBUG "IPPP: outbound frame filtered.\n");
		kfree_skb(skb);
		goto unlock;
	}
	if (!(ipt->active_filter
	      && sk_run_filter(skb, ipt->active_filter,
		               ipt->active_len) == 0)) {
		if (ipt->debug & 0x4)
			printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n");
		lp->huptimer = 0;
	}
	skb_pull(skb, 4);
#else /* CONFIG_IPPP_FILTER */
	lp->huptimer = 0;
#endif /* CONFIG_IPPP_FILTER */

	if (ipt->debug & 0x4)
		printk(KERN_DEBUG "xmit skb, len %d\n", (int) skb->len);
        if (ipts->debug & 0x40)
                isdn_ppp_frame_log("xmit0", skb->data, skb->len, 32,ipts->unit,lp->ppp_slot);

#ifdef CONFIG_ISDN_PPP_VJ
	if (proto == PPP_IP && ipts->pppcfg & SC_COMP_TCP) {	/* ipts here? probably yes, but check this again */
		struct sk_buff *new_skb;
	        unsigned short hl;
		/*
		 * we need to reserve enought space in front of
		 * sk_buff. old call to dev_alloc_skb only reserved
		 * 16 bytes, now we are looking what the driver want.
		 */
		hl = dev->drv[lp->isdn_device]->interface->hl_hdrlen + IPPP_MAX_HEADER;
		/* 
		 * Note: hl might still be insufficient because the method
		 * above does not account for a possibible MPPP slave channel
		 * which had larger HL header space requirements than the
		 * master.
		 */
		new_skb = alloc_skb(hl+skb->len, GFP_ATOMIC);
		if (new_skb) {
			u_char *buf;
			int pktlen;

			skb_reserve(new_skb, hl);
			new_skb->dev = skb->dev;
			skb_put(new_skb, skb->len);
			buf = skb->data;

			pktlen = slhc_compress(ipts->slcomp, skb->data, skb->len, new_skb->data,
				 &buf, !(ipts->pppcfg & SC_NO_TCP_CCID));

			if (buf != skb->data) {	
				if (new_skb->data != buf)
					printk(KERN_ERR "isdn_ppp: FATAL error after slhc_compress!!\n");
				dev_kfree_skb(skb);
				skb = new_skb;
			} else {
				dev_kfree_skb(new_skb);
			}

			skb_trim(skb, pktlen);
			if (skb->data[0] & SL_TYPE_COMPRESSED_TCP) {	/* cslip? style -> PPP */
				proto = PPP_VJC_COMP;
				skb->data[0] ^= SL_TYPE_COMPRESSED_TCP;
			} else {
				if (skb->data[0] >= SL_TYPE_UNCOMPRESSED_TCP)
					proto = PPP_VJC_UNCOMP;
				skb->data[0] = (skb->data[0] & 0x0f) | 0x40;
			}
		}
	}
#endif

	/*
	 * normal (single link) or bundle compression
	 */
	if(ipts->compflags & SC_COMP_ON) {
		/* We send compressed only if both down- und upstream
		   compression is negotiated, that means, CCP is up */
		if(ipts->compflags & SC_DECOMP_ON) {
			skb = isdn_ppp_compress(skb,&proto,ipt,ipts,0);
		} else {
			printk(KERN_DEBUG "isdn_ppp: CCP not yet up - sending as-is\n");
		}
	}

	if (ipt->debug & 0x24)
		printk(KERN_DEBUG "xmit2 skb, len %d, proto %04x\n", (int) skb->len, proto);

#ifdef CONFIG_ISDN_MPP
	if (ipt->mpppcfg & SC_MP_PROT) {
		/* we get mp_seqno from static isdn_net_local */
		long mp_seqno = ipts->mp_seqno;
		ipts->mp_seqno++;
		if (ipt->mpppcfg & SC_OUT_SHORT_SEQ) {
			unsigned char *data = isdn_ppp_skb_push(&skb, 3);
			if(!data)
				goto unlock;
			mp_seqno &= 0xfff;
			data[0] = MP_BEGIN_FRAG | MP_END_FRAG | ((mp_seqno >> 8) & 0xf);	/* (B)egin & (E)ndbit .. */
			data[1] = mp_seqno & 0xff;
			data[2] = proto;	/* PID compression */
		} else {
			unsigned char *data = isdn_ppp_skb_push(&skb, 5);
			if(!data)
				goto unlock;
			data[0] = MP_BEGIN_FRAG | MP_END_FRAG;	/* (B)egin & (E)ndbit .. */
			data[1] = (mp_seqno >> 16) & 0xff;	/* sequence number: 24bit */
			data[2] = (mp_seqno >> 8) & 0xff;
			data[3] = (mp_seqno >> 0) & 0xff;
			data[4] = proto;	/* PID compression */
		}
		proto = PPP_MP; /* MP Protocol, 0x003d */
	}
#endif

	/*
	 * 'link in bundle' compression  ...
	 */
	if(ipt->compflags & SC_LINK_COMP_ON)
		skb = isdn_ppp_compress(skb,&proto,ipt,ipts,1);

	if( (ipt->pppcfg & SC_COMP_PROT) && (proto <= 0xff) ) {
		unsigned char *data = isdn_ppp_skb_push(&skb,1);
		if(!data)
			goto unlock;
		data[0] = proto & 0xff;
	}
	else {
		unsigned char *data = isdn_ppp_skb_push(&skb,2);
		if(!data)
			goto unlock;
		data[0] = (proto >> 8) & 0xff;
		data[1] = proto & 0xff;
	}
	if(!(ipt->pppcfg & SC_COMP_AC)) {
		unsigned char *data = isdn_ppp_skb_push(&skb,2);
		if(!data)
			goto unlock;
		data[0] = 0xff;    /* All Stations */
		data[1] = 0x03;    /* Unnumbered information */
	}

	/* tx-stats are now updated via BSENT-callback */

	if (ipts->debug & 0x40) {
		printk(KERN_DEBUG "skb xmit: len: %d\n", (int) skb->len);
		isdn_ppp_frame_log("xmit", skb->data, skb->len, 32,ipt->unit,lp->ppp_slot);
	}
	
	isdn_net_writebuf_skb(lp, skb);

 unlock:
	spin_unlock_bh(&lp->xmit_lock);
 out:
	return retval;
}

#ifdef CONFIG_IPPP_FILTER
/*
 * check if this packet may trigger auto-dial.
 */

int isdn_ppp_autodial_filter(struct sk_buff *skb, isdn_net_local *lp)
{
	struct ippp_struct *is = ippp_table[lp->ppp_slot];
	u_int16_t proto;
	int drop = 0;

	switch (ntohs(skb->protocol)) {
	case ETH_P_IP:
		proto = PPP_IP;
		break;
	case ETH_P_IPX:
		proto = PPP_IPX;