| /* $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]=0x00; |
| 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) ) = 0x01; |
| 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) ) = 0x02; |
| 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 0x00: /* dl_data request */ |
| 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 0x01: /* dl_connect request */ |
| 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 0x02: /* dl_disconnect request */ |
| 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 0x03: /* changing lapb parameters requested */ |
| 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; |
| } |