/* $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 */ #include #include #include #include #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 = 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 */ 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; }