isdn_x25iface.c revision 475be4d85a274d0961593db41cf85689db1d583c
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 which 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/slab.h> 24#include <linux/wanrouter.h> 25#include <net/x25device.h> 26#include "isdn_x25iface.h" 27 28/* for debugging messages not to cause an oops when device pointer is NULL*/ 29#define MY_DEVNAME(dev) ((dev) ? (dev)->name : "DEVICE UNSPECIFIED") 30 31 32typedef struct isdn_x25iface_proto_data { 33 int magic; 34 enum wan_states state; 35 /* Private stuff, not to be accessed via proto_data. We provide the 36 other storage for the concap_proto instance here as well, 37 enabling us to allocate both with just one kmalloc(): */ 38 struct concap_proto priv; 39} ix25_pdata_t; 40 41 42 43/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */ 44static void isdn_x25iface_proto_del(struct concap_proto *); 45static int isdn_x25iface_proto_close(struct concap_proto *); 46static int isdn_x25iface_proto_restart(struct concap_proto *, 47 struct net_device *, 48 struct concap_device_ops *); 49static int isdn_x25iface_xmit(struct concap_proto *, struct sk_buff *); 50static int isdn_x25iface_receive(struct concap_proto *, struct sk_buff *); 51static int isdn_x25iface_connect_ind(struct concap_proto *); 52static int isdn_x25iface_disconn_ind(struct concap_proto *); 53 54 55static struct concap_proto_ops ix25_pops = { 56 &isdn_x25iface_proto_new, 57 &isdn_x25iface_proto_del, 58 &isdn_x25iface_proto_restart, 59 &isdn_x25iface_proto_close, 60 &isdn_x25iface_xmit, 61 &isdn_x25iface_receive, 62 &isdn_x25iface_connect_ind, 63 &isdn_x25iface_disconn_ind 64}; 65 66/* error message helper function */ 67static void illegal_state_warn(unsigned state, unsigned char firstbyte) 68{ 69 printk(KERN_WARNING "isdn_x25iface: firstbyte %x illegal in" 70 "current state %d\n", firstbyte, state); 71} 72 73/* check protocol data field for consistency */ 74static int pdata_is_bad(ix25_pdata_t *pda) { 75 76 if (pda && pda->magic == ISDN_X25IFACE_MAGIC) return 0; 77 printk(KERN_WARNING 78 "isdn_x25iface_xxx: illegal pointer to proto data\n"); 79 return 1; 80} 81 82/* create a new x25 interface protocol instance 83 */ 84struct concap_proto *isdn_x25iface_proto_new(void) 85{ 86 ix25_pdata_t *tmp = kmalloc(sizeof(ix25_pdata_t), GFP_KERNEL); 87 IX25DEBUG("isdn_x25iface_proto_new\n"); 88 if (tmp) { 89 tmp->magic = ISDN_X25IFACE_MAGIC; 90 tmp->state = WAN_UNCONFIGURED; 91 /* private data space used to hold the concap_proto data. 92 Only to be accessed via the returned pointer */ 93 spin_lock_init(&tmp->priv.lock); 94 tmp->priv.dops = NULL; 95 tmp->priv.net_dev = NULL; 96 tmp->priv.pops = &ix25_pops; 97 tmp->priv.flags = 0; 98 tmp->priv.proto_data = tmp; 99 return (&(tmp->priv)); 100 } 101 return NULL; 102}; 103 104/* close the x25iface encapsulation protocol 105 */ 106static int isdn_x25iface_proto_close(struct concap_proto *cprot) { 107 108 ix25_pdata_t *tmp; 109 int ret = 0; 110 ulong flags; 111 112 if (!cprot) { 113 printk(KERN_ERR "isdn_x25iface_proto_close: " 114 "invalid concap_proto pointer\n"); 115 return -1; 116 } 117 IX25DEBUG("isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot->net_dev)); 118 spin_lock_irqsave(&cprot->lock, flags); 119 cprot->dops = NULL; 120 cprot->net_dev = NULL; 121 tmp = cprot->proto_data; 122 if (pdata_is_bad(tmp)) { 123 ret = -1; 124 } else { 125 tmp->state = WAN_UNCONFIGURED; 126 } 127 spin_unlock_irqrestore(&cprot->lock, flags); 128 return ret; 129} 130 131/* Delete the x25iface encapsulation protocol instance 132 */ 133static void isdn_x25iface_proto_del(struct concap_proto *cprot) { 134 135 ix25_pdata_t *tmp; 136 137 IX25DEBUG("isdn_x25iface_proto_del \n"); 138 if (!cprot) { 139 printk(KERN_ERR "isdn_x25iface_proto_del: " 140 "concap_proto pointer is NULL\n"); 141 return; 142 } 143 tmp = cprot->proto_data; 144 if (tmp == NULL) { 145 printk(KERN_ERR "isdn_x25iface_proto_del: inconsistent " 146 "proto_data pointer (maybe already deleted?)\n"); 147 return; 148 } 149 /* close if the protocol is still open */ 150 if (cprot->dops) isdn_x25iface_proto_close(cprot); 151 /* freeing the storage should be sufficient now. But some additional 152 settings might help to catch wild pointer bugs */ 153 tmp->magic = 0; 154 cprot->proto_data = NULL; 155 156 kfree(tmp); 157 return; 158} 159 160/* (re-)initialize the data structures for x25iface encapsulation 161 */ 162static int isdn_x25iface_proto_restart(struct concap_proto *cprot, 163 struct net_device *ndev, 164 struct concap_device_ops *dops) 165{ 166 ix25_pdata_t *pda = cprot->proto_data; 167 ulong flags; 168 169 IX25DEBUG("isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev)); 170 171 if (pdata_is_bad(pda)) return -1; 172 173 if (!(dops && dops->data_req && dops->connect_req 174 && dops->disconn_req)) { 175 printk(KERN_WARNING "isdn_x25iface_restart: required dops" 176 " missing\n"); 177 isdn_x25iface_proto_close(cprot); 178 return -1; 179 } 180 spin_lock_irqsave(&cprot->lock, flags); 181 cprot->net_dev = ndev; 182 cprot->pops = &ix25_pops; 183 cprot->dops = dops; 184 pda->state = WAN_DISCONNECTED; 185 spin_unlock_irqrestore(&cprot->lock, flags); 186 return 0; 187} 188 189/* deliver a dl_data frame received from i4l HL driver to the network layer 190 */ 191static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb) 192{ 193 IX25DEBUG("isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev)); 194 if (((ix25_pdata_t *)(cprot->proto_data)) 195 ->state == WAN_CONNECTED) { 196 if (skb_push(skb, 1)) { 197 skb->data[0] = X25_IFACE_DATA; 198 skb->protocol = x25_type_trans(skb, cprot->net_dev); 199 netif_rx(skb); 200 return 0; 201 } 202 } 203 printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev)); 204 dev_kfree_skb(skb); 205 return -1; 206} 207 208/* a connection set up is indicated by lower layer 209 */ 210static int isdn_x25iface_connect_ind(struct concap_proto *cprot) 211{ 212 struct sk_buff *skb; 213 enum wan_states *state_p 214 = &(((ix25_pdata_t *)(cprot->proto_data))->state); 215 IX25DEBUG("isdn_x25iface_connect_ind %s \n" 216 , MY_DEVNAME(cprot->net_dev)); 217 if (*state_p == WAN_UNCONFIGURED) { 218 printk(KERN_WARNING 219 "isdn_x25iface_connect_ind while unconfigured %s\n" 220 , MY_DEVNAME(cprot->net_dev)); 221 return -1; 222 } 223 *state_p = WAN_CONNECTED; 224 225 skb = dev_alloc_skb(1); 226 if (skb) { 227 *(skb_put(skb, 1)) = X25_IFACE_CONNECT; 228 skb->protocol = x25_type_trans(skb, cprot->net_dev); 229 netif_rx(skb); 230 return 0; 231 } else { 232 printk(KERN_WARNING "isdn_x25iface_connect_ind: " 233 " out of memory -- disconnecting\n"); 234 cprot->dops->disconn_req(cprot); 235 return -1; 236 } 237} 238 239/* a disconnect is indicated by lower layer 240 */ 241static int isdn_x25iface_disconn_ind(struct concap_proto *cprot) 242{ 243 struct sk_buff *skb; 244 enum wan_states *state_p 245 = &(((ix25_pdata_t *)(cprot->proto_data))->state); 246 IX25DEBUG("isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot->net_dev)); 247 if (*state_p == WAN_UNCONFIGURED) { 248 printk(KERN_WARNING 249 "isdn_x25iface_disconn_ind while unconfigured\n"); 250 return -1; 251 } 252 if (!cprot->net_dev) return -1; 253 *state_p = WAN_DISCONNECTED; 254 skb = dev_alloc_skb(1); 255 if (skb) { 256 *(skb_put(skb, 1)) = X25_IFACE_DISCONNECT; 257 skb->protocol = x25_type_trans(skb, cprot->net_dev); 258 netif_rx(skb); 259 return 0; 260 } else { 261 printk(KERN_WARNING "isdn_x25iface_disconn_ind:" 262 " out of memory\n"); 263 return -1; 264 } 265} 266 267/* process a frame handed over to us from linux network layer. First byte 268 semantics as defined in Documentation/networking/x25-iface.txt 269*/ 270static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb) 271{ 272 unsigned char firstbyte = skb->data[0]; 273 enum wan_states *state = &((ix25_pdata_t *)cprot->proto_data)->state; 274 int ret = 0; 275 IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n", 276 MY_DEVNAME(cprot->net_dev), firstbyte, *state); 277 switch (firstbyte) { 278 case X25_IFACE_DATA: 279 if (*state == WAN_CONNECTED) { 280 skb_pull(skb, 1); 281 cprot->net_dev->trans_start = jiffies; 282 ret = (cprot->dops->data_req(cprot, skb)); 283 /* prepare for future retransmissions */ 284 if (ret) skb_push(skb, 1); 285 return ret; 286 } 287 illegal_state_warn(*state, firstbyte); 288 break; 289 case X25_IFACE_CONNECT: 290 if (*state == WAN_DISCONNECTED) { 291 *state = WAN_CONNECTING; 292 ret = cprot->dops->connect_req(cprot); 293 if (ret) { 294 /* reset state and notify upper layer about 295 * immidiatly failed attempts */ 296 isdn_x25iface_disconn_ind(cprot); 297 } 298 } else { 299 illegal_state_warn(*state, firstbyte); 300 } 301 break; 302 case X25_IFACE_DISCONNECT: 303 switch (*state) { 304 case WAN_DISCONNECTED: 305 /* Should not happen. However, give upper layer a 306 chance to recover from inconstistency but don't 307 trust the lower layer sending the disconn_confirm 308 when already disconnected */ 309 printk(KERN_WARNING "isdn_x25iface_xmit: disconnect " 310 " requested while disconnected\n"); 311 isdn_x25iface_disconn_ind(cprot); 312 break; /* prevent infinite loops */ 313 case WAN_CONNECTING: 314 case WAN_CONNECTED: 315 *state = WAN_DISCONNECTED; 316 cprot->dops->disconn_req(cprot); 317 break; 318 default: 319 illegal_state_warn(*state, firstbyte); 320 } 321 break; 322 case X25_IFACE_PARAMS: 323 printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb" 324 " options not yet supported\n"); 325 break; 326 default: 327 printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal" 328 " first byte %x ignored:\n", firstbyte); 329 } 330 dev_kfree_skb(skb); 331 return 0; 332} 333