diff options
Diffstat (limited to 'drivers/isdn/i4l/isdn_x25iface.c')
| -rw-r--r-- | drivers/isdn/i4l/isdn_x25iface.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/isdn/i4l/isdn_x25iface.c b/drivers/isdn/i4l/isdn_x25iface.c new file mode 100644 index 000000000000..4ab7600cf9c1 --- /dev/null +++ b/drivers/isdn/i4l/isdn_x25iface.c @@ -0,0 +1,328 @@ +/* $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 wich 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/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); */ +void isdn_x25iface_proto_del( struct concap_proto * ); +int isdn_x25iface_proto_close( struct concap_proto * ); +int isdn_x25iface_proto_restart( struct concap_proto *, + struct net_device *, + struct concap_device_ops *); +int isdn_x25iface_xmit( struct concap_proto *, struct sk_buff * ); +int isdn_x25iface_receive( struct concap_proto *, struct sk_buff * ); +int isdn_x25iface_connect_ind( struct concap_proto * ); +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 + */ +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 + */ +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 + */ +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 + */ +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 + */ +int isdn_x25iface_connect_ind(struct concap_proto *cprot) +{ + struct sk_buff * skb = dev_alloc_skb(1); + 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; + 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 + */ +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 + */ +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; +} |