path: root/drivers/net/wan/hdlc_fr.c

/*
 * Generic HDLC support routines for Linux
 * Frame Relay support
 *
 * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License
 * as published by the Free Software Foundation.
 *

            Theory of PVC state

 DCE mode:

 (exist,new) -> 0,0 when "PVC create" or if "link unreliable"
         0,x -> 1,1 if "link reliable" when sending FULL STATUS
         1,1 -> 1,0 if received FULL STATUS ACK

 (active)    -> 0 when "ifconfig PVC down" or "link unreliable" or "PVC create"
             -> 1 when "PVC up" and (exist,new) = 1,0

 DTE mode:
 (exist,new,active) = FULL STATUS if "link reliable"
		    = 0, 0, 0 if "link unreliable"
 No LMI:
 active = open and "link reliable"
 exist = new = not used

 CCITT LMI: ITU-T Q.933 Annex A
 ANSI LMI: ANSI T1.617 Annex D
 CISCO LMI: the original, aka "Gang of Four" LMI

*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/poll.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/etherdevice.h>
#include <linux/hdlc.h>

#undef DEBUG_PKT
#undef DEBUG_ECN
#undef DEBUG_LINK
#undef DEBUG_PROTO
#undef DEBUG_PVC

#define FR_UI			0x03
#define FR_PAD			0x00

#define NLPID_IP		0xCC
#define NLPID_IPV6		0x8E
#define NLPID_SNAP		0x80
#define NLPID_PAD		0x00
#define NLPID_CCITT_ANSI_LMI	0x08
#define NLPID_CISCO_LMI		0x09


#define LMI_CCITT_ANSI_DLCI	   0 /* LMI DLCI */
#define LMI_CISCO_DLCI		1023

#define LMI_CALLREF		0x00 /* Call Reference */
#define LMI_ANSI_LOCKSHIFT	0x95 /* ANSI locking shift */
#define LMI_ANSI_CISCO_REPTYPE	0x01 /* report type */
#define LMI_CCITT_REPTYPE	0x51
#define LMI_ANSI_CISCO_ALIVE	0x03 /* keep alive */
#define LMI_CCITT_ALIVE		0x53
#define LMI_ANSI_CISCO_PVCSTAT	0x07 /* PVC status */
#define LMI_CCITT_PVCSTAT	0x57

#define LMI_FULLREP		0x00 /* full report  */
#define LMI_INTEGRITY		0x01 /* link integrity report */
#define LMI_SINGLE		0x02 /* single PVC report */

#define LMI_STATUS_ENQUIRY      0x75
#define LMI_STATUS              0x7D /* reply */

#define LMI_REPT_LEN               1 /* report type element length */
#define LMI_INTEG_LEN              2 /* link integrity element length */

#define LMI_CCITT_CISCO_LENGTH	  13 /* LMI frame lengths */
#define LMI_ANSI_LENGTH		  14


typedef struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
	unsigned ea1:	1;
	unsigned cr:	1;
	unsigned dlcih:	6;
  
	unsigned ea2:	1;
	unsigned de:	1;
	unsigned becn:	1;
	unsigned fecn:	1;
	unsigned dlcil:	4;
#else
	unsigned dlcih:	6;
	unsigned cr:	1;
	unsigned ea1:	1;

	unsigned dlcil:	4;
	unsigned fecn:	1;
	unsigned becn:	1;
	unsigned de:	1;
	unsigned ea2:	1;
#endif
}__attribute__ ((packed)) fr_hdr;


typedef struct pvc_device_struct {
	struct net_device *frad;
	struct net_device *main;
	struct net_device *ether;	/* bridged Ethernet interface	*/
	struct pvc_device_struct *next;	/* Sorted in ascending DLCI order */
	int dlci;
	int open_count;

	struct {
		unsigned int new: 1;
		unsigned