|  | /* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $ | 
|  | * | 
|  | * Linux ISDN subsystem, X.25 related functions | 
|  | * | 
|  | * This software may be used and distributed according to the terms | 
|  | * of the GNU General Public License, incorporated herein by reference. | 
|  | * | 
|  | * stuff needed to support the Linux X.25 PLP code on top of devices that | 
|  | * can provide a lab_b service using the concap_proto mechanism. | 
|  | * This module supports a network interface which provides lapb_sematics | 
|  | * -- as defined in Documentation/networking/x25-iface.txt -- to | 
|  | * the upper layer and assumes that the lower layer provides a reliable | 
|  | * data link service by means of the concap_device_ops callbacks. | 
|  | * | 
|  | * Only protocol specific stuff goes here. Device specific stuff | 
|  | * goes to another -- device related -- concap_proto support source file. | 
|  | * | 
|  | */ | 
|  |  | 
|  | /* #include <linux/isdn.h> */ | 
|  | #include <linux/netdevice.h> | 
|  | #include <linux/concap.h> | 
|  | #include <linux/slab.h> | 
|  | #include <linux/wanrouter.h> | 
|  | #include <net/x25device.h> | 
|  | #include "isdn_x25iface.h" | 
|  |  | 
|  | /* for debugging messages not to cause an oops when device pointer is NULL*/ | 
|  | #define MY_DEVNAME(dev)  ( (dev) ? (dev)->name : "DEVICE UNSPECIFIED" ) | 
|  |  | 
|  |  | 
|  | typedef struct isdn_x25iface_proto_data { | 
|  | int magic; | 
|  | enum wan_states state; | 
|  | /* Private stuff, not to be accessed via proto_data. We provide the | 
|  | other storage for the concap_proto instance here as well, | 
|  | enabling us to allocate both with just one kmalloc(): */ | 
|  | struct concap_proto priv; | 
|  | } ix25_pdata_t; | 
|  |  | 
|  |  | 
|  |  | 
|  | /* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */ | 
|  | static void isdn_x25iface_proto_del( struct concap_proto * ); | 
|  | static int isdn_x25iface_proto_close( struct concap_proto * ); | 
|  | static int isdn_x25iface_proto_restart( struct concap_proto *, | 
|  | struct net_device *, | 
|  | struct concap_device_ops *); | 
|  | static int isdn_x25iface_xmit( struct concap_proto *, struct sk_buff * ); | 
|  | static int isdn_x25iface_receive( struct concap_proto *, struct sk_buff * ); | 
|  | static int isdn_x25iface_connect_ind( struct concap_proto * ); | 
|  | static int isdn_x25iface_disconn_ind( struct concap_proto * ); | 
|  |  | 
|  |  | 
|  | static struct concap_proto_ops ix25_pops = { | 
|  | &isdn_x25iface_proto_new, | 
|  | &isdn_x25iface_proto_del, | 
|  | &isdn_x25iface_proto_restart, | 
|  | &isdn_x25iface_proto_close, | 
|  | &isdn_x25iface_xmit, | 
|  | &isdn_x25iface_receive, | 
|  | &isdn_x25iface_connect_ind, | 
|  | &isdn_x25iface_disconn_ind | 
|  | }; | 
|  |  | 
|  | /* error message helper function */ | 
|  | static void illegal_state_warn( unsigned state, unsigned char firstbyte) | 
|  | { | 
|  | printk( KERN_WARNING "isdn_x25iface: firstbyte %x illegal in" | 
|  | "current state %d\n",firstbyte, state ); | 
|  | } | 
|  |  | 
|  | /* check protocol data field for consistency */ | 
|  | static int pdata_is_bad( ix25_pdata_t * pda ){ | 
|  |  | 
|  | if( pda  &&  pda -> magic == ISDN_X25IFACE_MAGIC ) return 0; | 
|  | printk( KERN_WARNING | 
|  | "isdn_x25iface_xxx: illegal pointer to proto data\n" ); | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* create a new x25 interface protocol instance | 
|  | */ | 
|  | struct concap_proto * isdn_x25iface_proto_new(void) | 
|  | { | 
|  | ix25_pdata_t * tmp = kmalloc(sizeof(ix25_pdata_t),GFP_KERNEL); | 
|  | IX25DEBUG("isdn_x25iface_proto_new\n"); | 
|  | if( tmp ){ | 
|  | tmp -> magic = ISDN_X25IFACE_MAGIC; | 
|  | tmp -> state = WAN_UNCONFIGURED; | 
|  | /* private data space used to hold the concap_proto data. | 
|  | Only to be accessed via the returned pointer */ | 
|  | spin_lock_init(&tmp->priv.lock); | 
|  | tmp -> priv.dops       = NULL; | 
|  | tmp -> priv.net_dev    = NULL; | 
|  | tmp -> priv.pops       = &ix25_pops; | 
|  | tmp -> priv.flags      = 0; | 
|  | tmp -> priv.proto_data = tmp; | 
|  | return( &(tmp -> priv) ); | 
|  | } | 
|  | return NULL; | 
|  | }; | 
|  |  | 
|  | /* close the x25iface encapsulation protocol | 
|  | */ | 
|  | static int isdn_x25iface_proto_close(struct concap_proto *cprot){ | 
|  |  | 
|  | ix25_pdata_t *tmp; | 
|  | int ret = 0; | 
|  | ulong flags; | 
|  |  | 
|  | if( ! cprot ){ | 
|  | printk( KERN_ERR "isdn_x25iface_proto_close: " | 
|  | "invalid concap_proto pointer\n" ); | 
|  | return -1; | 
|  | } | 
|  | IX25DEBUG( "isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot -> net_dev) ); | 
|  | spin_lock_irqsave(&cprot->lock, flags); | 
|  | cprot -> dops    = NULL; | 
|  | cprot -> net_dev = NULL; | 
|  | tmp = cprot -> proto_data; | 
|  | if( pdata_is_bad( tmp ) ){ | 
|  | ret = -1; | 
|  | } else { | 
|  | tmp -> state = WAN_UNCONFIGURED; | 
|  | } | 
|  | spin_unlock_irqrestore(&cprot->lock, flags); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* Delete the x25iface encapsulation protocol instance | 
|  | */ | 
|  | static void isdn_x25iface_proto_del(struct concap_proto *cprot){ | 
|  |  | 
|  | ix25_pdata_t * tmp; | 
|  |  | 
|  | IX25DEBUG( "isdn_x25iface_proto_del \n" ); | 
|  | if( ! cprot ){ | 
|  | printk( KERN_ERR "isdn_x25iface_proto_del: " | 
|  | "concap_proto pointer is NULL\n" ); | 
|  | return; | 
|  | } | 
|  | tmp = cprot -> proto_data; | 
|  | if( tmp == NULL ){ | 
|  | printk( KERN_ERR "isdn_x25iface_proto_del: inconsistent " | 
|  | "proto_data pointer (maybe already deleted?)\n"); | 
|  | return; | 
|  | } | 
|  | /* close if the protocol is still open */ | 
|  | if( cprot -> dops ) isdn_x25iface_proto_close(cprot); | 
|  | /* freeing the storage should be sufficient now. But some additional | 
|  | settings might help to catch wild pointer bugs */ | 
|  | tmp -> magic = 0; | 
|  | cprot -> proto_data = NULL; | 
|  |  | 
|  | kfree( tmp ); | 
|  | return; | 
|  | } | 
|  |  | 
|  | /* (re-)initialize the data structures for x25iface encapsulation | 
|  | */ | 
|  | static int isdn_x25iface_proto_restart(struct concap_proto *cprot, | 
|  | struct net_device *ndev, | 
|  | struct concap_device_ops *dops) | 
|  | { | 
|  | ix25_pdata_t * pda = cprot -> proto_data ; | 
|  | ulong flags; | 
|  |  | 
|  | IX25DEBUG( "isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev) ); | 
|  |  | 
|  | if ( pdata_is_bad( pda ) ) return -1; | 
|  |  | 
|  | if( !( dops  && dops -> data_req && dops -> connect_req | 
|  | && dops -> disconn_req )  ){ | 
|  | printk( KERN_WARNING "isdn_x25iface_restart: required dops" | 
|  | " missing\n" ); | 
|  | isdn_x25iface_proto_close(cprot); | 
|  | return -1; | 
|  | } | 
|  | spin_lock_irqsave(&cprot->lock, flags); | 
|  | cprot -> net_dev = ndev; | 
|  | cprot -> pops = &ix25_pops; | 
|  | cprot -> dops = dops; | 
|  | pda -> state = WAN_DISCONNECTED; | 
|  | spin_unlock_irqrestore(&cprot->lock, flags); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* deliver a dl_data frame received from i4l HL driver to the network layer | 
|  | */ | 
|  | static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb) | 
|  | { | 
|  | IX25DEBUG( "isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev) ); | 
|  | if ( ( (ix25_pdata_t*) (cprot->proto_data) ) | 
|  | -> state == WAN_CONNECTED ){ | 
|  | if( skb_push(skb, 1)){ | 
|  | skb->data[0] = X25_IFACE_DATA; | 
|  | skb->protocol = x25_type_trans(skb, cprot->net_dev); | 
|  | netif_rx(skb); | 
|  | return 0; | 
|  | } | 
|  | } | 
|  | printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev) ); | 
|  | dev_kfree_skb(skb); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | /* a connection set up is indicated by lower layer | 
|  | */ | 
|  | static int isdn_x25iface_connect_ind(struct concap_proto *cprot) | 
|  | { | 
|  | struct sk_buff * skb; | 
|  | enum wan_states *state_p | 
|  | = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state); | 
|  | IX25DEBUG( "isdn_x25iface_connect_ind %s \n" | 
|  | , MY_DEVNAME(cprot->net_dev) ); | 
|  | if( *state_p == WAN_UNCONFIGURED ){ | 
|  | printk(KERN_WARNING | 
|  | "isdn_x25iface_connect_ind while unconfigured %s\n" | 
|  | , MY_DEVNAME(cprot->net_dev) ); | 
|  | return -1; | 
|  | } | 
|  | *state_p = WAN_CONNECTED; | 
|  |  | 
|  | skb = dev_alloc_skb(1); | 
|  | if( skb ){ | 
|  | *(skb_put(skb, 1)) = X25_IFACE_CONNECT; | 
|  | skb->protocol = x25_type_trans(skb, cprot->net_dev); | 
|  | netif_rx(skb); | 
|  | return 0; | 
|  | } else { | 
|  | printk(KERN_WARNING "isdn_x25iface_connect_ind: " | 
|  | " out of memory -- disconnecting\n"); | 
|  | cprot -> dops -> disconn_req(cprot); | 
|  | return -1; | 
|  | } | 
|  | } | 
|  |  | 
|  | /* a disconnect is indicated by lower layer | 
|  | */ | 
|  | static int isdn_x25iface_disconn_ind(struct concap_proto *cprot) | 
|  | { | 
|  | struct sk_buff *skb; | 
|  | enum wan_states *state_p | 
|  | = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state); | 
|  | IX25DEBUG( "isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot -> net_dev) ); | 
|  | if( *state_p == WAN_UNCONFIGURED ){ | 
|  | printk(KERN_WARNING | 
|  | "isdn_x25iface_disconn_ind while unconfigured\n"); | 
|  | return -1; | 
|  | } | 
|  | if(! cprot -> net_dev) return -1; | 
|  | *state_p = WAN_DISCONNECTED; | 
|  | skb = dev_alloc_skb(1); | 
|  | if( skb ){ | 
|  | *(skb_put(skb, 1)) = X25_IFACE_DISCONNECT; | 
|  | skb->protocol = x25_type_trans(skb, cprot->net_dev); | 
|  | netif_rx(skb); | 
|  | return 0; | 
|  | } else { | 
|  | printk(KERN_WARNING "isdn_x25iface_disconn_ind:" | 
|  | " out of memory\n"); | 
|  | return -1; | 
|  | } | 
|  | } | 
|  |  | 
|  | /* process a frame handed over to us from linux network layer. First byte | 
|  | semantics as defined in Documentation/networking/x25-iface.txt | 
|  | */ | 
|  | static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb) | 
|  | { | 
|  | unsigned char firstbyte = skb->data[0]; | 
|  | enum wan_states *state = &((ix25_pdata_t*)cprot->proto_data)->state; | 
|  | int ret = 0; | 
|  | IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n", | 
|  | MY_DEVNAME(cprot->net_dev), firstbyte, *state); | 
|  | switch ( firstbyte ){ | 
|  | case X25_IFACE_DATA: | 
|  | if( *state == WAN_CONNECTED ){ | 
|  | skb_pull(skb, 1); | 
|  | cprot -> net_dev -> trans_start = jiffies; | 
|  | ret = ( cprot -> dops -> data_req(cprot, skb) ); | 
|  | /* prepare for future retransmissions */ | 
|  | if( ret ) skb_push(skb,1); | 
|  | return ret; | 
|  | } | 
|  | illegal_state_warn( *state, firstbyte ); | 
|  | break; | 
|  | case X25_IFACE_CONNECT: | 
|  | if( *state == WAN_DISCONNECTED ){ | 
|  | *state = WAN_CONNECTING; | 
|  | ret = cprot -> dops -> connect_req(cprot); | 
|  | if(ret){ | 
|  | /* reset state and notify upper layer about | 
|  | * immidiatly failed attempts */ | 
|  | isdn_x25iface_disconn_ind(cprot); | 
|  | } | 
|  | } else { | 
|  | illegal_state_warn( *state, firstbyte ); | 
|  | } | 
|  | break; | 
|  | case X25_IFACE_DISCONNECT: | 
|  | switch ( *state ){ | 
|  | case WAN_DISCONNECTED: | 
|  | /* Should not happen. However, give upper layer a | 
|  | chance to recover from inconstistency  but don't | 
|  | trust the lower layer sending the disconn_confirm | 
|  | when already disconnected */ | 
|  | printk(KERN_WARNING "isdn_x25iface_xmit: disconnect " | 
|  | " requested while disconnected\n" ); | 
|  | isdn_x25iface_disconn_ind(cprot); | 
|  | break; /* prevent infinite loops */ | 
|  | case WAN_CONNECTING: | 
|  | case WAN_CONNECTED: | 
|  | *state = WAN_DISCONNECTED; | 
|  | cprot -> dops -> disconn_req(cprot); | 
|  | break; | 
|  | default: | 
|  | illegal_state_warn( *state, firstbyte ); | 
|  | } | 
|  | break; | 
|  | case X25_IFACE_PARAMS: | 
|  | printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb" | 
|  | " options not yet supported\n"); | 
|  | break; | 
|  | default: | 
|  | printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal" | 
|  | " first byte %x ignored:\n", firstbyte); | 
|  | } | 
|  | dev_kfree_skb(skb); | 
|  | return 0; | 
|  | } |