isdn_x25iface.c revision 3e206b0a66fcaf39dbef92640ce6a63d51fc5c53
1/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $ 2 * 3 * Linux ISDN subsystem, X.25 related functions 4 * 5 * This software may be used and distributed according to the terms 6 * of the GNU General Public License, incorporated herein by reference. 7 * 8 * stuff needed to support the Linux X.25 PLP code on top of devices that 9 * can provide a lab_b service using the concap_proto mechanism. 10 * This module supports a network interface wich provides lapb_sematics 11 * -- as defined in Documentation/networking/x25-iface.txt -- to 12 * the upper layer and assumes that the lower layer provides a reliable 13 * data link service by means of the concap_device_ops callbacks. 14 * 15 * Only protocol specific stuff goes here. Device specific stuff 16 * goes to another -- device related -- concap_proto support source file. 17 * 18 */ 19 20/* #include <linux/isdn.h> */ 21#include <linux/netdevice.h> 22#include <linux/concap.h> 23#include <linux/wanrouter.h> 24#include <net/x25device.h> 25#include "isdn_x25iface.h" 26 27/* for debugging messages not to cause an oops when device pointer is NULL*/ 28#define MY_DEVNAME(dev) ( (dev) ? (dev)->name : "DEVICE UNSPECIFIED" ) 29 30 31typedef struct isdn_x25iface_proto_data { 32 int magic; 33 enum wan_states state; 34 /* Private stuff, not to be accessed via proto_data. We provide the 35 other storage for the concap_proto instance here as well, 36 enabling us to allocate both with just one kmalloc(): */ 37 struct concap_proto priv; 38} ix25_pdata_t; 39 40 41 42/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */ 43static void isdn_x25iface_proto_del( struct concap_proto * ); 44static int isdn_x25iface_proto_close( struct concap_proto * ); 45static int isdn_x25iface_proto_restart( struct concap_proto *, 46 struct net_device *, 47 struct concap_device_ops *); 48static int isdn_x25iface_xmit( struct concap_proto *, struct sk_buff * ); 49static int isdn_x25iface_receive( struct concap_proto *, struct sk_buff * ); 50static int isdn_x25iface_connect_ind( struct concap_proto * ); 51static int isdn_x25iface_disconn_ind( struct concap_proto * ); 52 53 54static struct concap_proto_ops ix25_pops = { 55 &isdn_x25iface_proto_new, 56 &isdn_x25iface_proto_del, 57 &isdn_x25iface_proto_restart, 58 &isdn_x25iface_proto_close, 59 &isdn_x25iface_xmit, 60 &isdn_x25iface_receive, 61 &isdn_x25iface_connect_ind, 62 &isdn_x25iface_disconn_ind 63}; 64 65/* error message helper function */ 66static void illegal_state_warn( unsigned state, unsigned char firstbyte) 67{ 68 printk( KERN_WARNING "isdn_x25iface: firstbyte %x illegal in" 69 "current state %d\n",firstbyte, state ); 70} 71 72/* check protocol data field for consistency */ 73static int pdata_is_bad( ix25_pdata_t * pda ){ 74 75 if( pda && pda -> magic == ISDN_X25IFACE_MAGIC ) return 0; 76 printk( KERN_WARNING 77 "isdn_x25iface_xxx: illegal pointer to proto data\n" ); 78 return 1; 79} 80 81/* create a new x25 interface protocol instance 82 */ 83struct concap_proto * isdn_x25iface_proto_new(void) 84{ 85 ix25_pdata_t * tmp = kmalloc(sizeof(ix25_pdata_t),GFP_KERNEL); 86 IX25DEBUG("isdn_x25iface_proto_new\n"); 87 if( tmp ){ 88 tmp -> magic = ISDN_X25IFACE_MAGIC; 89 tmp -> state = WAN_UNCONFIGURED; 90 /* private data space used to hold the concap_proto data. 91 Only to be accessed via the returned pointer */ 92 spin_lock_init(&tmp->priv.lock); 93 tmp -> priv.dops = NULL; 94 tmp -> priv.net_dev = NULL; 95 tmp -> priv.pops = &ix25_pops; 96 tmp -> priv.flags = 0; 97 tmp -> priv.proto_data = tmp; 98 return( &(tmp -> priv) ); 99 } 100 return NULL; 101}; 102 103/* close the x25iface encapsulation protocol 104 */ 105static int isdn_x25iface_proto_close(struct concap_proto *cprot){ 106 107 ix25_pdata_t *tmp; 108 int ret = 0; 109 ulong flags; 110 111 if( ! cprot ){ 112 printk( KERN_ERR "isdn_x25iface_proto_close: " 113 "invalid concap_proto pointer\n" ); 114 return -1; 115 } 116 IX25DEBUG( "isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot -> net_dev) ); 117 spin_lock_irqsave(&cprot->lock, flags); 118 cprot -> dops = NULL; 119 cprot -> net_dev = NULL; 120 tmp = cprot -> proto_data; 121 if( pdata_is_bad( tmp ) ){ 122 ret = -1; 123 } else { 124 tmp -> state = WAN_UNCONFIGURED; 125 } 126 spin_unlock_irqrestore(&cprot->lock, flags); 127 return ret; 128} 129 130/* Delete the x25iface encapsulation protocol instance 131 */ 132static void isdn_x25iface_proto_del(struct concap_proto *cprot){ 133 134 ix25_pdata_t * tmp; 135 136 IX25DEBUG( "isdn_x25iface_proto_del \n" ); 137 if( ! cprot ){ 138 printk( KERN_ERR "isdn_x25iface_proto_del: " 139 "concap_proto pointer is NULL\n" ); 140 return; 141 } 142 tmp = cprot -> proto_data; 143 if( tmp == NULL ){ 144 printk( KERN_ERR "isdn_x25iface_proto_del: inconsistent " 145 "proto_data pointer (maybe already deleted?)\n"); 146 return; 147 } 148 /* close if the protocol is still open */ 149 if( cprot -> dops ) isdn_x25iface_proto_close(cprot); 150 /* freeing the storage should be sufficient now. But some additional 151 settings might help to catch wild pointer bugs */ 152 tmp -> magic = 0; 153 cprot -> proto_data = NULL; 154 155 kfree( tmp ); 156 return; 157} 158 159/* (re-)initialize the data structures for x25iface encapsulation 160 */ 161static int isdn_x25iface_proto_restart(struct concap_proto *cprot, 162 struct net_device *ndev, 163 struct concap_device_ops *dops) 164{ 165 ix25_pdata_t * pda = cprot -> proto_data ; 166 ulong flags; 167 168 IX25DEBUG( "isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev) ); 169 170 if ( pdata_is_bad( pda ) ) return -1; 171 172 if( !( dops && dops -> data_req && dops -> connect_req 173 && dops -> disconn_req ) ){ 174 printk( KERN_WARNING "isdn_x25iface_restart: required dops" 175 " missing\n" ); 176 isdn_x25iface_proto_close(cprot); 177 return -1; 178 } 179 spin_lock_irqsave(&cprot->lock, flags); 180 cprot -> net_dev = ndev; 181 cprot -> pops = &ix25_pops; 182 cprot -> dops = dops; 183 pda -> state = WAN_DISCONNECTED; 184 spin_unlock_irqrestore(&cprot->lock, flags); 185 return 0; 186} 187 188/* deliver a dl_data frame received from i4l HL driver to the network layer 189 */ 190static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb) 191{ 192 IX25DEBUG( "isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev) ); 193 if ( ( (ix25_pdata_t*) (cprot->proto_data) ) 194 -> state == WAN_CONNECTED ){ 195 if( skb_push(skb, 1)){ 196 skb -> data[0]=0x00; 197 skb->protocol = x25_type_trans(skb, cprot->net_dev); 198 netif_rx(skb); 199 return 0; 200 } 201 } 202 printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev) ); 203 dev_kfree_skb(skb); 204 return -1; 205} 206 207/* a connection set up is indicated by lower layer 208 */ 209static int isdn_x25iface_connect_ind(struct concap_proto *cprot) 210{ 211 struct sk_buff * skb = dev_alloc_skb(1); 212 enum wan_states *state_p 213 = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state); 214 IX25DEBUG( "isdn_x25iface_connect_ind %s \n" 215 , MY_DEVNAME(cprot->net_dev) ); 216 if( *state_p == WAN_UNCONFIGURED ){ 217 printk(KERN_WARNING 218 "isdn_x25iface_connect_ind while unconfigured %s\n" 219 , MY_DEVNAME(cprot->net_dev) ); 220 return -1; 221 } 222 *state_p = WAN_CONNECTED; 223 if( skb ){ 224 *( skb_put(skb, 1) ) = 0x01; 225 skb->protocol = x25_type_trans(skb, cprot->net_dev); 226 netif_rx(skb); 227 return 0; 228 } else { 229 printk(KERN_WARNING "isdn_x25iface_connect_ind: " 230 " out of memory -- disconnecting\n"); 231 cprot -> dops -> disconn_req(cprot); 232 return -1; 233 } 234} 235 236/* a disconnect is indicated by lower layer 237 */ 238static int isdn_x25iface_disconn_ind(struct concap_proto *cprot) 239{ 240 struct sk_buff *skb; 241 enum wan_states *state_p 242 = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state); 243 IX25DEBUG( "isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot -> net_dev) ); 244 if( *state_p == WAN_UNCONFIGURED ){ 245 printk(KERN_WARNING 246 "isdn_x25iface_disconn_ind while unconfigured\n"); 247 return -1; 248 } 249 if(! cprot -> net_dev) return -1; 250 *state_p = WAN_DISCONNECTED; 251 skb = dev_alloc_skb(1); 252 if( skb ){ 253 *( skb_put(skb, 1) ) = 0x02; 254 skb->protocol = x25_type_trans(skb, cprot->net_dev); 255 netif_rx(skb); 256 return 0; 257 } else { 258 printk(KERN_WARNING "isdn_x25iface_disconn_ind:" 259 " out of memory\n"); 260 return -1; 261 } 262} 263 264/* process a frame handed over to us from linux network layer. First byte 265 semantics as defined in Documentation/networking/x25-iface.txt 266 */ 267static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb) 268{ 269 unsigned char firstbyte = skb->data[0]; 270 enum wan_states *state = &((ix25_pdata_t*)cprot->proto_data)->state; 271 int ret = 0; 272 IX25DEBUG( "isdn_x25iface_xmit: %s first=%x state=%d \n", MY_DEVNAME(cprot -> net_dev), firstbyte, *state ); 273 switch ( firstbyte ){ 274 case 0x00: /* dl_data request */ 275 if( *state == WAN_CONNECTED ){ 276 skb_pull(skb, 1); 277 cprot -> net_dev -> trans_start = jiffies; 278 ret = ( cprot -> dops -> data_req(cprot, skb) ); 279 /* prepare for future retransmissions */ 280 if( ret ) skb_push(skb,1); 281 return ret; 282 } 283 illegal_state_warn( *state, firstbyte ); 284 break; 285 case 0x01: /* dl_connect request */ 286 if( *state == WAN_DISCONNECTED ){ 287 *state = WAN_CONNECTING; 288 ret = cprot -> dops -> connect_req(cprot); 289 if(ret){ 290 /* reset state and notify upper layer about 291 * immidiatly failed attempts */ 292 isdn_x25iface_disconn_ind(cprot); 293 } 294 } else { 295 illegal_state_warn( *state, firstbyte ); 296 } 297 break; 298 case 0x02: /* dl_disconnect request */ 299 switch ( *state ){ 300 case WAN_DISCONNECTED: 301 /* Should not happen. However, give upper layer a 302 chance to recover from inconstistency but don't 303 trust the lower layer sending the disconn_confirm 304 when already disconnected */ 305 printk(KERN_WARNING "isdn_x25iface_xmit: disconnect " 306 " requested while disconnected\n" ); 307 isdn_x25iface_disconn_ind(cprot); 308 break; /* prevent infinite loops */ 309 case WAN_CONNECTING: 310 case WAN_CONNECTED: 311 *state = WAN_DISCONNECTED; 312 cprot -> dops -> disconn_req(cprot); 313 break; 314 default: 315 illegal_state_warn( *state, firstbyte ); 316 } 317 break; 318 case 0x03: /* changing lapb parameters requested */ 319 printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb" 320 " options not yet supported\n"); 321 break; 322 default: 323 printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal" 324 " first byte %x ignored:\n", firstbyte); 325 } 326 dev_kfree_skb(skb); 327 return 0; 328} 329