ppp.c

powerpc内核mpc8241linux系统下net驱动程序

			ppp->escape = 0;
		} else if (chr == PPP_ESCAPE) {
			ppp->escape = PPP_TRANS;
			continue;
		}

		/*
		 * Allocate an skbuff on the first character received.
		 * The 128 is room for VJ header expansion and FCS.
		 */
		if (skb == NULL) {
			skb = dev_alloc_skb(ppp->mru + 128 + PPP_HDRLEN);
			if (skb == NULL) {
				if (ppp->flags & SC_DEBUG)
					printk(KERN_DEBUG "couldn't "
					       "alloc skb for recv\n");
				ppp->toss = 1;
				continue;
			}
		}

		/*
		 * Decompress A/C and protocol compression here.
		 */
		if (skb->len == 0 && chr != PPP_ALLSTATIONS) {
			p = skb_put(skb, 2);
			p[0] = PPP_ALLSTATIONS;
			p[1] = PPP_UI;
		}
		if (skb->len == 2 && (chr & 1) != 0) {
			p = skb_put(skb, 1);
			p[0] = 0;
		}

		/*
		 * Check if we've overflowed the MRU
		 */
		if (skb->len >= ppp->mru + PPP_HDRLEN + 2
		    || skb_tailroom(skb) <= 0) {
			++ppp->estats.rx_length_errors;
			ppp->toss = 0xC0;
			if (ppp->flags & SC_DEBUG)
				printk(KERN_DEBUG "rcv frame too long: "
				       "len=%d mru=%d hroom=%d troom=%d\n",
				       skb->len, ppp->mru, skb_headroom(skb),
				       skb_tailroom(skb));
			continue;
		}

		/*
		 * Store the character and update the FCS.
		 */
		p = skb_put(skb, 1);
		*p = chr;
		ppp->rfcs = PPP_FCS(ppp->rfcs, chr);
	}
	ppp->rpkt = skb;
}

/*************************************************************
 * PPP NETWORK INTERFACE SUPPORT
 *	The following code implements the PPP network
 *	interface device and handles those parts of
 *	the PPP processing which are independent of the
 *	type of hardware link being used, including
 *	VJ and packet compression.
 *************************************************************/

/*
 * Network device driver callback routines
 */

static int ppp_init_dev(struct device *dev);
static int ppp_dev_open(struct device *);
static int ppp_dev_ioctl(struct device *dev, struct ifreq *ifr, int cmd);
static int ppp_dev_close(struct device *);
static int ppp_dev_xmit(struct sk_buff *, struct device *);
static struct net_device_stats *ppp_dev_stats (struct device *);

/*
 * Information for the protocol decoder
 */

typedef int (*pfn_proto)  (struct ppp *, struct sk_buff *);

typedef struct ppp_proto_struct {
	int		proto;
	pfn_proto	func;
} ppp_proto_type;

static int rcv_proto_ip		(struct ppp *, struct sk_buff *);
static int rcv_proto_ipv6	(struct ppp *, struct sk_buff *);
static int rcv_proto_ipx	(struct ppp *, struct sk_buff *);
static int rcv_proto_at		(struct ppp *, struct sk_buff *);
static int rcv_proto_vjc_comp	(struct ppp *, struct sk_buff *);
static int rcv_proto_vjc_uncomp (struct ppp *, struct sk_buff *);
static int rcv_proto_ccp	(struct ppp *, struct sk_buff *);
static int rcv_proto_unknown	(struct ppp *, struct sk_buff *);

static
ppp_proto_type proto_list[] = {
	{ PPP_IP,	  rcv_proto_ip	       },
	{ PPP_IPV6,	  rcv_proto_ipv6       },
	{ PPP_IPX,	  rcv_proto_ipx	       },
	{ PPP_AT,	  rcv_proto_at	       },
	{ PPP_VJC_COMP,	  rcv_proto_vjc_comp   },
	{ PPP_VJC_UNCOMP, rcv_proto_vjc_uncomp },
	{ PPP_CCP,	  rcv_proto_ccp	       },
	{ 0,		  rcv_proto_unknown    }  /* !!! MUST BE LAST !!! */
};

/*
 * Called when the PPP network interface device is actually created.
 */
static int
ppp_init_dev (struct device *dev)
{
	dev->hard_header_len  = PPP_HDRLEN;

	/* device INFO */
	dev->mtu	      = PPP_MTU;
	dev->hard_start_xmit  = ppp_dev_xmit;
	dev->open	      = ppp_dev_open;
	dev->stop	      = ppp_dev_close;
	dev->get_stats	      = ppp_dev_stats;
	dev->do_ioctl	      = ppp_dev_ioctl;
	dev->addr_len	      = 0;
	dev->tx_queue_len     = 10;
	dev->type	      = ARPHRD_PPP;

	dev_init_buffers(dev);

	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;

	return 0;
}

/*
 * Callback from the network layer when the device goes up.
 */

static int
ppp_dev_open (struct device *dev)
{
	struct ppp *ppp = dev2ppp(dev);

	if (!ppp->inuse || ppp2tty(ppp) == NULL) {
		printk(KERN_ERR "ppp: %s not active\n", dev->name);
		return -ENXIO;
	}

	MOD_INC_USE_COUNT;

	return 0;
}

/*
 * Callback from the network layer when the ppp device goes down.
 */

static int
ppp_dev_close (struct device *dev)
{
	struct ppp *ppp = dev2ppp (dev);

	CHECK_PPP_MAGIC(ppp);

	/* ppp_dev_close may be called with tbusy==1 so we must set it to 0 */
	dev->tbusy=0;

	MOD_DEC_USE_COUNT;

	return 0;
}

static inline void
get_vj_stats(struct vjstat *vj, struct slcompress *slc)
{
	vj->vjs_packets    = slc->sls_o_compressed + slc->sls_o_uncompressed;
	vj->vjs_compressed = slc->sls_o_compressed;
	vj->vjs_searches   = slc->sls_o_searches;
	vj->vjs_misses     = slc->sls_o_misses;
	vj->vjs_errorin    = slc->sls_i_error;
	vj->vjs_tossed     = slc->sls_i_tossed;
	vj->vjs_uncompressedin = slc->sls_i_uncompressed;
	vj->vjs_compressedin   = slc->sls_i_compressed;
}

/*
 * Callback from the network layer to process the sockioctl functions.
 */
static int
ppp_dev_ioctl (struct device *dev, struct ifreq *ifr, int cmd)
{
	struct ppp *ppp = dev2ppp(dev);
	int nb;
	union {
		struct ppp_stats stats;
		struct ppp_comp_stats cstats;
		char vers[32];
	} u;

	CHECK_PPP_MAGIC(ppp);

	memset(&u, 0, sizeof(u));
	switch (cmd) {
	case SIOCGPPPSTATS:
		u.stats.p = ppp->stats;
		if (ppp->slcomp != NULL)
			get_vj_stats(&u.stats.vj, ppp->slcomp);
		nb = sizeof(u.stats);
		break;

	case SIOCGPPPCSTATS:
		if (ppp->sc_xc_state != NULL)
			(*ppp->sc_xcomp->comp_stat)
				(ppp->sc_xc_state, &u.cstats.c);
		if (ppp->sc_rc_state != NULL)
			(*ppp->sc_rcomp->decomp_stat)
				(ppp->sc_rc_state, &u.cstats.d);
		nb = sizeof(u.cstats);
		break;

	case SIOCGPPPVER:
		strcpy(u.vers, szVersion);
		nb = strlen(u.vers) + 1;
		break;

	default:
		return -EINVAL;
	}

	if (copy_to_user((void *) ifr->ifr_ifru.ifru_data, &u, nb))
		return -EFAULT;
	return 0;
}

/*
 * Process the generic PPP ioctls, i.e. those which are not specific
 * to any particular type of hardware link.
 */
static int
ppp_ioctl(struct ppp *ppp, unsigned int param2, unsigned long param3)
{
	register int temp_i = 0, oldflags;
	int error = -EFAULT;
	unsigned long flags;
	struct ppp_idle cur_ddinfo;
	struct npioctl npi;

	CHECK_PPP(-ENXIO);

	/*
	 * The user must have an euid of root to do these requests.
	 */
	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	switch (param2) {
	case PPPIOCSMRU:
		/*
		 * Set the MRU value
		 */
		if (get_user(temp_i, (int *) param3))
			break;
		if (temp_i < PPP_MRU)
			temp_i = PPP_MRU;
		ppp->mru = temp_i;
		if (ppp->flags & SC_DEBUG)
			printk(KERN_INFO
			       "ppp_ioctl: set mru to %x\n", temp_i);
		error = 0;
		break;

	case PPPIOCGFLAGS:
		/*
		 * Fetch the current flags
		 */
		temp_i = ppp->flags & SC_MASK;
#ifndef CHECK_CHARACTERS /* Don't generate errors if we don't check chars. */
		temp_i |= SC_RCV_B7_1 | SC_RCV_B7_0 |
			  SC_RCV_ODDP | SC_RCV_EVNP;
#endif
		if (put_user(temp_i, (int *) param3))
			break;
		error = 0;
		break;

	case PPPIOCSFLAGS:
		/*
		 * Set the flags for the various options
		 */
		if (get_user(temp_i, (int *) param3))
			break;

		if (ppp->flags & ~temp_i & SC_CCP_OPEN)
			ppp_ccp_closed(ppp);

		save_flags(flags);
		cli();
		oldflags = ppp->flags;
		temp_i = (temp_i & SC_MASK) | (oldflags & ~SC_MASK);
		ppp->flags = temp_i;
		restore_flags(flags);

		if ((oldflags | temp_i) & SC_DEBUG)
			printk(KERN_INFO
			       "ppp_ioctl: set flags to %x\n", temp_i);
		error = 0;
		break;

	case PPPIOCSCOMPRESS:
		/*
		 * Set the compression mode
		 */
		error = ppp_set_compression
			(ppp, (struct ppp_option_data *) param3);
		break;

	case PPPIOCGUNIT:
		/*
		 * Obtain the unit number for this device.
		 */
		if (put_user(ppp->line, (int *) param3))
			break;
		if (ppp->flags & SC_DEBUG)
			printk(KERN_INFO
			       "ppp_ioctl: get unit: %d\n", ppp->line);
		error = 0;
		break;

	case PPPIOCSDEBUG:
		/*
		 * Set the debug level
		 */
		if (get_user(temp_i, (int *) param3))
			break;
		temp_i = (temp_i & 0x1F) << 16;

		if ((ppp->flags | temp_i) & SC_DEBUG)
			printk(KERN_INFO
			       "ppp_ioctl: set dbg flags to %x\n", temp_i);

		save_flags(flags);
		cli();
		ppp->flags = (ppp->flags & ~0x1F0000) | temp_i;
		restore_flags(flags);
		error = 0;
		break;

	case PPPIOCGDEBUG:
		/*
		 * Get the debug level
		 */
		temp_i = (ppp->flags >> 16) & 0x1F;
		if (put_user(temp_i, (int *) param3))
			break;
		error = 0;
		break;

	case PPPIOCGIDLE:
		/*
		 * Get the times since the last send/receive frame operation
		 */
		/* change absolute times to relative times. */
		cur_ddinfo.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
		cur_ddinfo.recv_idle = (jiffies - ppp->last_recv) / HZ;
		if (copy_to_user((void *) param3, &cur_ddinfo,
				 sizeof (cur_ddinfo)))
			break;
		error = 0;
		break;

	case PPPIOCSMAXCID:
		/*
		 * Set the maximum VJ header compression slot number.
		 */
		if (get_user(temp_i, (int *) param3))
			break;
		error = -EINVAL;
		if (temp_i < 2 || temp_i > 255)
			break;
		++temp_i;
		if (ppp->flags & SC_DEBUG)
			printk(KERN_INFO "ppp_ioctl: set maxcid to %d\n",
			       temp_i);
		if (ppp->slcomp != NULL)
			slhc_free(ppp->slcomp);
		ppp->slcomp = slhc_init(16, temp_i);

		error = -ENOMEM;
		if (ppp->slcomp == NULL) {
			printk(KERN_ERR "ppp: no memory for VJ compression\n");
			break;
		}
		error = 0;
		break;

	case PPPIOCGNPMODE:
	case PPPIOCSNPMODE:
		if (copy_from_user(&npi, (void *) param3, sizeof(npi)))
			break;

		switch (npi.protocol) {
		case PPP_IP:
			npi.protocol = NP_IP;
			break;
		case PPP_IPX:
			npi.protocol = NP_IPX;
			break;
		case PPP_AT:
			npi.protocol = NP_AT;
			break;
		default:
			if (ppp->flags & SC_DEBUG)
				printk(KERN_DEBUG "pppioc[gs]npmode: "
				       "invalid proto %d\n", npi.protocol);
			error = -EINVAL;
			goto out;
		}

		if (param2 == PPPIOCGNPMODE) {
			npi.mode = ppp->sc_npmode[npi.protocol];
			if (copy_to_user((void *) param3, &npi, sizeof(npi)))
				break;
		} else {
			ppp->sc_npmode[npi.protocol] = npi.mode;
			if (ppp->flags & SC_DEBUG)
				printk(KERN_DEBUG "ppp: set np %d to %d\n",
				       npi.protocol, npi.mode);
			mark_bh(NET_BH);
		}
		error = 0;
		break;

	default:
		/*
		 *  All other ioctl() events will come here.
		 */
		if (ppp->flags & SC_DEBUG)
			printk(KERN_ERR
			       "ppp_ioctl: invalid ioctl: %x, addr %lx\n",
			       param2, param3);

		error = -ENOIOCTLCMD;
		break;
	}
out:
	return error;
}

/*
 * Process the set-compression ioctl.
 */
static int
ppp_set_compression (struct ppp *ppp, struct ppp_option_data *odp)
{
	struct compressor *cp;
	int error, nb;
	unsigned long flags;
	__u8 *ptr;
	__u8 ccp_option[CCP_MAX_OPTION_LENGTH];
	struct ppp_option_data data;

	/*
	 * Fetch the compression parameters
	 */
	error = -EFAULT;
	if (copy_from_user(&data, odp, sizeof (data)))
		goto out;

	nb  = data.length;
	ptr = data.ptr;
	if ((unsigned) nb >= CCP_MAX_OPTION_LENGTH)
		nb = CCP_MAX_OPTION_LENGTH;

	if (copy_from_user(ccp_option, ptr, nb))
		goto out;

	error = -EINVAL;
	if (ccp_option[1] < 2)	/* preliminary check on the length byte */
		goto out;

	save_flags(flags);
	cli();
	ppp->flags &= ~(data.transmit? SC_COMP_RUN: SC_DECOMP_RUN);
	restore_flags(flags);

	cp = find_compressor (ccp_option[0]);
#ifdef CONFIG_KMOD
	if (cp == NULL) {
		char modname[32];
		sprintf(modname, "ppp-compress-%d", ccp_option[0]);
		request_module(modname);
		cp = find_compressor(ccp_option[0]);
	}
#endif /* CONFIG_KMOD */

	if (cp == NULL) {
		if (ppp->flags & SC_DEBUG)
			printk(KERN_DEBUG
			       "%s: no compressor for [%x %x %x], %x\n",
			       ppp->name, ccp_option[0], ccp_option[1],
			       ccp_option[2], nb);
		goto out;		/* compressor not loaded */
	}

	/*
	 * Found a handler for the protocol - try to allocate
	 * a compressor or decompressor.
	 */
	error = 0;
	if (data.transmit) {
		if (ppp->sc_xc_state != NULL)
			(*ppp->sc_xcomp->comp_free)(ppp->sc_xc_state);
		ppp->sc_xc_state = NULL;

		ppp->sc_xcomp	 = cp;
		ppp->sc_xc_state = cp->comp_alloc(ccp_option, nb);
		if (ppp->sc_xc_state == NULL) {
			if (ppp->flags & SC_DEBUG)
				printk(KERN_DEBUG "%s: comp_alloc failed\n",
				       ppp->name);
			error = -ENOBUFS;
		}
	} else {
		if (ppp->sc_rc_state != NULL)
			(*ppp->sc_rcomp->decomp_free)(ppp->sc_rc_state);
		ppp->sc_rc_state = NULL;

		ppp->sc_rcomp	 = cp;
		ppp->sc_rc_state = cp->decomp_alloc(ccp_option, nb);
		if (ppp->sc_rc_state == NULL) {
			if (ppp->flags & SC_DEBUG)
				printk(KERN_DEBUG "%s: decomp_alloc failed\n",
				       ppp->name);
			error = -ENOBUFS;
		}
	}
out:
	return error;
}

/*
 * Handle a CCP packet.
 *
 * The CCP packet is passed along to the pppd process just like any
 * other PPP frame. The difference is that some processing needs to be
 * immediate or the compressors will become confused on the peer.
 */

static void ppp_proto_ccp(struct ppp *ppp, __u8 *dp, int len, int rcvd)
{
	int slen    = CCP_LENGTH(dp);
	__u8 *opt = dp	 + CCP_HDRLEN;
	int opt_len = slen - CCP_HDRLEN;
	unsigned long flags;

	if (slen > len)
		return;

	if (ppp->flags & SC_DEBUG)
		printk(KERN_DEBUG "ppp_proto_ccp rcvd=%d code=%x flags=%x\n",