hdlc.c

上传linux-jx2410的源代码

/*
 * Generic HDLC support routines for Linux
 *
 * Copyright (C) 1999, 2000 Krzysztof Halasa <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Current status:
 *    - this is work in progress
 *    - not heavily tested on SMP
 *    - currently supported:
 *	* raw IP-in-HDLC
 *	* Cisco HDLC
 *	* Frame Relay with ANSI or CCITT LMI (both user and network side)
 *	* PPP (using syncppp.c)
 *	* X.25
 *
 * Use sethdlc utility to set line parameters, protocol and PVCs
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/pkt_sched.h>
#include <linux/inetdevice.h>
#include <linux/lapb.h>
#include <linux/rtnetlink.h>
#include <linux/hdlc.h>

/* #define DEBUG_PKT */
/* #define DEBUG_HARD_HEADER */
/* #define DEBUG_FECN */
/* #define DEBUG_BECN */

static const char* version = "HDLC support module revision 1.02 for Linux 2.4";


#define CISCO_MULTICAST		0x8F	/* Cisco multicast address */
#define CISCO_UNICAST		0x0F	/* Cisco unicast address */
#define CISCO_KEEPALIVE		0x8035	/* Cisco keepalive protocol */
#define CISCO_SYS_INFO		0x2000	/* Cisco interface/system info */
#define CISCO_ADDR_REQ		0	/* Cisco address request */
#define CISCO_ADDR_REPLY	1	/* Cisco address reply */
#define CISCO_KEEPALIVE_REQ	2	/* Cisco keepalive request */

static int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);

/********************************************************
 *
 * Cisco HDLC support
 *
 *******************************************************/

static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
			     u16 type, void *daddr, void *saddr,
			     unsigned int len)
{
	hdlc_header *data;
#ifdef DEBUG_HARD_HEADER
	printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name);
#endif

	skb_push(skb, sizeof(hdlc_header));
	data = (hdlc_header*)skb->data;
	if (type == CISCO_KEEPALIVE)
		data->address = CISCO_MULTICAST;
	else
		data->address = CISCO_UNICAST;
	data->control = 0;
	data->protocol = htons(type);

	return sizeof(hdlc_header);
}



static void cisco_keepalive_send(hdlc_device *hdlc, u32 type,
				 u32 par1, u32 par2)
{
	struct sk_buff *skb;
	cisco_packet *data;

	skb = dev_alloc_skb(sizeof(hdlc_header)+sizeof(cisco_packet));
	if (!skb) {
		printk(KERN_WARNING "%s: Memory squeeze on cisco_keepalive_send()\n",
			       hdlc_to_name(hdlc));
		return;
	}
	skb_reserve(skb, 4);
	cisco_hard_header(skb, hdlc_to_dev(hdlc), CISCO_KEEPALIVE,
			  NULL, NULL, 0);
	data = (cisco_packet*)skb->tail;

	data->type = htonl(type);
	data->par1 = htonl(par1);
	data->par2 = htonl(par2);
	data->rel = 0xFFFF;
	data->time = htonl(jiffies * 1000 / HZ);

	skb_put(skb, sizeof(cisco_packet));
	skb->priority = TC_PRIO_CONTROL;
	skb->dev = hdlc_to_dev(hdlc);

	dev_queue_xmit(skb);
}



static void cisco_netif(hdlc_device *hdlc, struct sk_buff *skb)
{
	hdlc_header *data = (hdlc_header*)skb->data;
	cisco_packet *cisco_data;
	struct in_device *in_dev;
	u32 addr, mask;

	if (skb->len<sizeof(hdlc_header))
		goto rx_error;

	if (data->address != CISCO_MULTICAST &&
	    data->address != CISCO_UNICAST)
		goto rx_error;

	skb_pull(skb, sizeof(hdlc_header));

	switch(ntohs(data->protocol)) {
	case ETH_P_IP:
	case ETH_P_IPX:
	case ETH_P_IPV6:
		skb->protocol = data->protocol;
		skb->dev = hdlc_to_dev(hdlc);
		netif_rx(skb);
		return;

	case CISCO_SYS_INFO:
		/* Packet is not needed, drop it. */
		dev_kfree_skb_any(skb);
		return;

	case CISCO_KEEPALIVE:
		if (skb->len != CISCO_PACKET_LEN &&
		    skb->len != CISCO_BIG_PACKET_LEN) {
			printk(KERN_INFO "%s: Invalid length of Cisco "
			       "control packet (%d bytes)\n",
			       hdlc_to_name(hdlc), skb->len);
			goto rx_error;
		}

		cisco_data = (cisco_packet*)skb->data;

		switch(ntohl (cisco_data->type)) {
		case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
			in_dev = hdlc_to_dev(hdlc)->ip_ptr;
			addr = 0;
			mask = ~0; /* is the mask correct? */

			if (in_dev != NULL) {
				struct in_ifaddr **ifap = &in_dev->ifa_list;

				while (*ifap != NULL) {
					if (strcmp(hdlc_to_name(hdlc),
						   (*ifap)->ifa_label) == 0) {
						addr = (*ifap)->ifa_local;
						mask = (*ifap)->ifa_mask;
						break;
					}
					ifap = &(*ifap)->ifa_next;
				}

				cisco_keepalive_send(hdlc, CISCO_ADDR_REPLY,
						     addr, mask);
			}
			dev_kfree_skb_any(skb);
			return;

		case CISCO_ADDR_REPLY:
			printk(KERN_INFO "%s: Unexpected Cisco IP address "
			       "reply\n", hdlc_to_name(hdlc));
			goto rx_error;

		case CISCO_KEEPALIVE_REQ:
			hdlc->lmi.rxseq = ntohl(cisco_data->par1);
			if (ntohl(cisco_data->par2) == hdlc->lmi.txseq) {
				hdlc->lmi.last_poll = jiffies;
				if (!(hdlc->lmi.state & LINK_STATE_RELIABLE)) {
					u32 sec, min, hrs, days;
					sec = ntohl(cisco_data->time) / 1000;
					min = sec / 60; sec -= min * 60;
					hrs = min / 60; min -= hrs * 60;
					days = hrs / 24; hrs -= days * 24;
					printk(KERN_INFO "%s: Link up (peer "
					       "uptime %ud%uh%um%us)\n",
					       hdlc_to_name(hdlc), days, hrs,
					       min, sec);
				}
				hdlc->lmi.state |= LINK_STATE_RELIABLE;
			}

			dev_kfree_skb_any(skb);
			return;
		} /* switch(keepalive type) */
	} /* switch(protocol) */

	printk(KERN_INFO "%s: Unsupported protocol %x\n", hdlc_to_name(hdlc),
	       data->protocol);
	dev_kfree_skb_any(skb);
	return;

 rx_error:
	hdlc->stats.rx_errors++; /* Mark error */
	dev_kfree_skb_any(skb);
}



static void cisco_timer(unsigned long arg)
{
	hdlc_device *hdlc = (hdlc_device*)arg;

	if ((hdlc->lmi.state & LINK_STATE_RELIABLE) &&
	    (jiffies - hdlc->lmi.last_poll >= hdlc->lmi.T392 * HZ)) {
		hdlc->lmi.state &= ~LINK_STATE_RELIABLE;
		printk(KERN_INFO "%s: Link down\n", hdlc_to_name(hdlc));
	}

	cisco_keepalive_send(hdlc, CISCO_KEEPALIVE_REQ, ++hdlc->lmi.txseq,
			     hdlc->lmi.rxseq);
	hdlc->timer.expires = jiffies + hdlc->lmi.T391*HZ;

	hdlc->timer.function = cisco_timer;
	hdlc->timer.data = arg;
	add_timer(&hdlc->timer);
}



/******************************************************************
 *
 *     generic Frame Relay routines
 *
 *****************************************************************/


static int fr_hard_header(struct sk_buff *skb, struct net_device *dev,
			  u16 type, void *daddr, void *saddr, unsigned int len)
{
	u16 head_len;

	if (!daddr)
		daddr = dev->broadcast;

#ifdef DEBUG_HARD_HEADER
	printk(KERN_DEBUG "%s: fr_hard_header called\n", dev->name);
#endif

	switch(type) {
	case ETH_P_IP:
		head_len = 4;
		skb_push(skb, head_len);
		skb->data[3] = NLPID_IP;
		break;

	case ETH_P_IPV6:
		head_len = 4;
		skb_push(skb, head_len);
		skb->data[3] = NLPID_IPV6;
		break;

	case LMI_PROTO:
		head_len = 4;
		skb_push(skb, head_len);
		skb->data[3] = LMI_PROTO;
		break;

	default:
		head_len = 10;
		skb_push(skb, head_len);
		skb->data[3] = FR_PAD;
		skb->data[4] = NLPID_SNAP;
		skb->data[5] = FR_PAD;
		skb->data[6] = FR_PAD;
		skb->data[7] = FR_PAD;
		skb->data[8] = type>>8;
		skb->data[9] = (u8)type;
	}

	memcpy(skb->data, daddr, 2);
	skb->data[2] = FR_UI;

	return head_len;
}



static inline void fr_log_dlci_active(pvc_device *pvc)
{
	printk(KERN_INFO "%s: %sactive%s\n", pvc_to_name(pvc),
	       pvc->state & PVC_STATE_ACTIVE ? "" : "in",
	       pvc->state & PVC_STATE_NEW ? " new" : "");
}



static inline u8 fr_lmi_nextseq(u8 x)
{
	x++;
	return x ? x : 1;
}



static void fr_lmi_send(hdlc_device *hdlc, int fullrep)
{
	struct sk_buff *skb;
	pvc_device *pvc = hdlc->first_pvc;
	int len = mode_is(hdlc, MODE_FR_ANSI) ? LMI_ANSI_LENGTH : LMI_LENGTH;
	int stat_len = 3;
	u8 *data;
	int i = 0;

	if (mode_is(hdlc, MODE_DCE) && fullrep) {
		len += hdlc->pvc_count * (2 + stat_len);
		if (len > HDLC_MAX_MTU) {
			printk(KERN_WARNING "%s: Too many PVCs while sending "
			       "LMI full report\n", hdlc_to_name(hdlc));
			return;
		}
	}

	skb = dev_alloc_skb(len);
	if (!skb) {
		printk(KERN_WARNING "%s: Memory squeeze on fr_lmi_send()\n",
			       hdlc_to_name(hdlc));
		return;
	}
	memset(skb->data, 0, len);
	skb_reserve(skb, 4);
	fr_hard_header(skb, hdlc_to_dev(hdlc), LMI_PROTO, NULL, NULL, 0);
	data = skb->tail;
	data[i++] = LMI_CALLREF;
	data[i++] = mode_is(hdlc, MODE_DCE) ? LMI_STATUS : LMI_STATUS_ENQUIRY;
	if (mode_is(hdlc, MODE_FR_ANSI))
		data[i++] = LMI_ANSI_LOCKSHIFT;
	data[i++] = mode_is(hdlc, MODE_FR_CCITT) ? LMI_CCITT_REPTYPE :
		LMI_REPTYPE;
	data[i++] = LMI_REPT_LEN;
	data[i++] = fullrep ? LMI_FULLREP : LMI_INTEGRITY;

	data[i++] = mode_is(hdlc, MODE_FR_CCITT) ? LMI_CCITT_ALIVE : LMI_ALIVE;
	data[i++] = LMI_INTEG_LEN;
	data[i++] = hdlc->lmi.txseq = fr_lmi_nextseq(hdlc->lmi.txseq);
	data[i++] = hdlc->lmi.rxseq;

	if (mode_is(hdlc, MODE_DCE) && fullrep) {
		while (pvc) {
			data[i++] = mode_is(hdlc, MODE_FR_CCITT) ?
				LMI_CCITT_PVCSTAT:LMI_PVCSTAT;
			data[i++] = stat_len;

			if ((hdlc->lmi.state & LINK_STATE_RELIABLE) &&
			    (pvc->netdev.flags & IFF_UP) &&
			    !(pvc->state & (PVC_STATE_ACTIVE|PVC_STATE_NEW))) {
				pvc->state |= PVC_STATE_NEW;
				fr_log_dlci_active(pvc);
			}

			dlci_to_status(hdlc, netdev_dlci(&pvc->netdev),
				       data+i, pvc->state);
			i += stat_len;
			pvc = pvc->next;
		}
	}

	skb_put(skb, i);
	skb->priority = TC_PRIO_CONTROL;
	skb->dev = hdlc_to_dev(hdlc);

	dev_queue_xmit(skb);
}



static void fr_timer(unsigned long arg)
{
	hdlc_device *hdlc = (hdlc_device*)arg;
	int i, cnt = 0, reliable;
	u32 list;

	if (mode_is(hdlc, MODE_DCE))
		reliable = (jiffies - hdlc->lmi.last_poll < hdlc->lmi.T392*HZ);
	else {
		hdlc->lmi.last_errors <<= 1; /* Shift the list */
		if (hdlc->lmi.state & LINK_STATE_REQUEST) {
			printk(KERN_INFO "%s: No LMI status reply received\n",
			       hdlc_to_name(hdlc));
			hdlc->lmi.last_errors |= 1;
		}

		for (i = 0, list = hdlc->lmi.last_errors; i < hdlc->lmi.N393;
		     i++, list >>= 1)
			cnt += (list & 1);	/* errors count */

		reliable = (cnt < hdlc->lmi.N392);
	}

	if ((hdlc->lmi.state & LINK_STATE_RELIABLE) !=
	    (reliable ? LINK_STATE_RELIABLE : 0)) {
		pvc_device *pvc = hdlc->first_pvc;

		while (pvc) {/* Deactivate all PVCs */
			pvc->state &= ~(PVC_STATE_NEW | PVC_STATE_ACTIVE);
			pvc = pvc->next;
		}

		hdlc->lmi.state ^= LINK_STATE_RELIABLE;
		printk(KERN_INFO "%s: Link %sreliable\n", hdlc_to_name(hdlc),
		       reliable ? "" : "un");

		if (reliable) {
			hdlc->lmi.N391cnt = 0; /* Request full status */
			hdlc->lmi.state |= LINK_STATE_CHANGED;
		}
	}

	if (mode_is(hdlc, MODE_DCE))
		hdlc->timer.expires = jiffies + hdlc->lmi.T392*HZ;
	else {
		if (hdlc->lmi.N391cnt)
			hdlc->lmi.N391cnt--;

		fr_lmi_send(hdlc, hdlc->lmi.N391cnt == 0);

		hdlc->lmi.state |= LINK_STATE_REQUEST;
		hdlc->timer.expires = jiffies + hdlc->lmi.T391*HZ;
	}

	hdlc->timer.function = fr_timer;
	hdlc->timer.data = arg;
	add_timer(&hdlc->timer);
}



static int fr_lmi_recv(hdlc_device *hdlc, struct sk_buff *skb)
{
	int stat_len;
	pvc_device *pvc;
	int reptype = -1, error;
	u8 rxseq, txseq;
	int i;

	if (skb->len < (mode_is(hdlc, MODE_FR_ANSI) ?
			LMI_ANSI_LENGTH : LMI_LENGTH)) {
		printk(KERN_INFO "%s: Short LMI frame\n", hdlc_to_name(hdlc));
		return 1;
	}

	if (skb->data[5] != (!mode_is(hdlc, MODE_DCE) ?
			     LMI_STATUS : LMI_STATUS_ENQUIRY)) {
		printk(KERN_INFO "%s: LMI msgtype=%x, Not LMI status %s\n",
		       hdlc_to_name(hdlc), skb->data[2],
		       mode_is(hdlc, MODE_DCE) ? "enquiry" : "reply");
		return 1;
	}

	i = mode_is(hdlc, MODE_FR_ANSI) ? 7 : 6;

	if (skb->data[i] !=
	    (mode_is(hdlc, MODE_FR_CCITT) ? LMI_CCITT_REPTYPE : LMI_REPTYPE)) {
		printk(KERN_INFO "%s: Not a report type=%x\n",
		       hdlc_to_name(hdlc), skb->data[i]);
		return 1;
	}
	i++;

	i++;				/* Skip length field */