1 /* 2 * Generic HDLC support routines for Linux 3 * Cisco HDLC support 4 * 5 * Copyright (C) 2000 - 2006 Krzysztof Halasa <khc@pm.waw.pl> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of version 2 of the GNU General Public License 9 * as published by the Free Software Foundation. 10 */ 11 12 #include <linux/errno.h> 13 #include <linux/hdlc.h> 14 #include <linux/if_arp.h> 15 #include <linux/inetdevice.h> 16 #include <linux/init.h> 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/pkt_sched.h> 20 #include <linux/poll.h> 21 #include <linux/rtnetlink.h> 22 #include <linux/skbuff.h> 23 24 #undef DEBUG_HARD_HEADER 25 26 #define CISCO_MULTICAST 0x8F /* Cisco multicast address */ 27 #define CISCO_UNICAST 0x0F /* Cisco unicast address */ 28 #define CISCO_KEEPALIVE 0x8035 /* Cisco keepalive protocol */ 29 #define CISCO_SYS_INFO 0x2000 /* Cisco interface/system info */ 30 #define CISCO_ADDR_REQ 0 /* Cisco address request */ 31 #define CISCO_ADDR_REPLY 1 /* Cisco address reply */ 32 #define CISCO_KEEPALIVE_REQ 2 /* Cisco keepalive request */ 33 34 35 struct hdlc_header { 36 u8 address; 37 u8 control; 38 __be16 protocol; 39 }__packed; 40 41 42 struct cisco_packet { 43 __be32 type; /* code */ 44 __be32 par1; 45 __be32 par2; 46 __be16 rel; /* reliability */ 47 __be32 time; 48 }__packed; 49 #define CISCO_PACKET_LEN 18 50 #define CISCO_BIG_PACKET_LEN 20 51 52 53 struct cisco_state { 54 cisco_proto settings; 55 56 struct timer_list timer; 57 spinlock_t lock; 58 unsigned long last_poll; 59 int up; 60 u32 txseq; /* TX sequence number, 0 = none */ 61 u32 rxseq; /* RX sequence number */ 62 }; 63 64 65 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr); 66 67 68 static inline struct cisco_state* state(hdlc_device *hdlc) 69 { 70 return (struct cisco_state *)hdlc->state; 71 } 72 73 74 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev, 75 u16 type, const void *daddr, const void *saddr, 76 unsigned int len) 77 { 78 struct hdlc_header *data; 79 #ifdef DEBUG_HARD_HEADER 80 printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name); 81 #endif 82 83 skb_push(skb, sizeof(struct hdlc_header)); 84 data = (struct hdlc_header*)skb->data; 85 if (type == CISCO_KEEPALIVE) 86 data->address = CISCO_MULTICAST; 87 else 88 data->address = CISCO_UNICAST; 89 data->control = 0; 90 data->protocol = htons(type); 91 92 return sizeof(struct hdlc_header); 93 } 94 95 96 97 static void cisco_keepalive_send(struct net_device *dev, u32 type, 98 __be32 par1, __be32 par2) 99 { 100 struct sk_buff *skb; 101 struct cisco_packet *data; 102 103 skb = dev_alloc_skb(sizeof(struct hdlc_header) + 104 sizeof(struct cisco_packet)); 105 if (!skb) { 106 printk(KERN_WARNING 107 "%s: Memory squeeze on cisco_keepalive_send()\n", 108 dev->name); 109 return; 110 } 111 skb_reserve(skb, 4); 112 cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0); 113 data = (struct cisco_packet*)(skb->data + 4); 114 115 data->type = htonl(type); 116 data->par1 = par1; 117 data->par2 = par2; 118 data->rel = cpu_to_be16(0xFFFF); 119 /* we will need do_div here if 1000 % HZ != 0 */ 120 data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ)); 121 122 skb_put(skb, sizeof(struct cisco_packet)); 123 skb->priority = TC_PRIO_CONTROL; 124 skb->dev = dev; 125 skb_reset_network_header(skb); 126 127 dev_queue_xmit(skb); 128 } 129 130 131 132 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev) 133 { 134 struct hdlc_header *data = (struct hdlc_header*)skb->data; 135 136 if (skb->len < sizeof(struct hdlc_header)) 137 return cpu_to_be16(ETH_P_HDLC); 138 139 if (data->address != CISCO_MULTICAST && 140 data->address != CISCO_UNICAST) 141 return cpu_to_be16(ETH_P_HDLC); 142 143 switch (data->protocol) { 144 case cpu_to_be16(ETH_P_IP): 145 case cpu_to_be16(ETH_P_IPX): 146 case cpu_to_be16(ETH_P_IPV6): 147 skb_pull(skb, sizeof(struct hdlc_header)); 148 return data->protocol; 149 default: 150 return cpu_to_be16(ETH_P_HDLC); 151 } 152 } 153 154 155 static int cisco_rx(struct sk_buff *skb) 156 { 157 struct net_device *dev = skb->dev; 158 hdlc_device *hdlc = dev_to_hdlc(dev); 159 struct cisco_state *st = state(hdlc); 160 struct hdlc_header *data = (struct hdlc_header*)skb->data; 161 struct cisco_packet *cisco_data; 162 struct in_device *in_dev; 163 __be32 addr, mask; 164 u32 ack; 165 166 if (skb->len < sizeof(struct hdlc_header)) 167 goto rx_error; 168 169 if (data->address != CISCO_MULTICAST && 170 data->address != CISCO_UNICAST) 171 goto rx_error; 172 173 switch (ntohs(data->protocol)) { 174 case CISCO_SYS_INFO: 175 /* Packet is not needed, drop it. */ 176 dev_kfree_skb_any(skb); 177 return NET_RX_SUCCESS; 178 179 case CISCO_KEEPALIVE: 180 if ((skb->len != sizeof(struct hdlc_header) + 181 CISCO_PACKET_LEN) && 182 (skb->len != sizeof(struct hdlc_header) + 183 CISCO_BIG_PACKET_LEN)) { 184 printk(KERN_INFO "%s: Invalid length of Cisco control" 185 " packet (%d bytes)\n", dev->name, skb->len); 186 goto rx_error; 187 } 188 189 cisco_data = (struct cisco_packet*)(skb->data + sizeof 190 (struct hdlc_header)); 191 192 switch (ntohl (cisco_data->type)) { 193 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */ 194 rcu_read_lock(); 195 in_dev = __in_dev_get_rcu(dev); 196 addr = 0; 197 mask = ~cpu_to_be32(0); /* is the mask correct? */ 198 199 if (in_dev != NULL) { 200 struct in_ifaddr **ifap = &in_dev->ifa_list; 201 202 while (*ifap != NULL) { 203 if (strcmp(dev->name, 204 (*ifap)->ifa_label) == 0) { 205 addr = (*ifap)->ifa_local; 206 mask = (*ifap)->ifa_mask; 207 break; 208 } 209 ifap = &(*ifap)->ifa_next; 210 } 211 212 cisco_keepalive_send(dev, CISCO_ADDR_REPLY, 213 addr, mask); 214 } 215 rcu_read_unlock(); 216 dev_kfree_skb_any(skb); 217 return NET_RX_SUCCESS; 218 219 case CISCO_ADDR_REPLY: 220 printk(KERN_INFO "%s: Unexpected Cisco IP address " 221 "reply\n", dev->name); 222 goto rx_error; 223 224 case CISCO_KEEPALIVE_REQ: 225 spin_lock(&st->lock); 226 st->rxseq = ntohl(cisco_data->par1); 227 ack = ntohl(cisco_data->par2); 228 if (ack && (ack == st->txseq || 229 /* our current REQ may be in transit */ 230 ack == st->txseq - 1)) { 231 st->last_poll = jiffies; 232 if (!st->up) { 233 u32 sec, min, hrs, days; 234 sec = ntohl(cisco_data->time) / 1000; 235 min = sec / 60; sec -= min * 60; 236 hrs = min / 60; min -= hrs * 60; 237 days = hrs / 24; hrs -= days * 24; 238 printk(KERN_INFO "%s: Link up (peer " 239 "uptime %ud%uh%um%us)\n", 240 dev->name, days, hrs, min, sec); 241 netif_dormant_off(dev); 242 st->up = 1; 243 } 244 } 245 spin_unlock(&st->lock); 246 247 dev_kfree_skb_any(skb); 248 return NET_RX_SUCCESS; 249 } /* switch (keepalive type) */ 250 } /* switch (protocol) */ 251 252 printk(KERN_INFO "%s: Unsupported protocol %x\n", dev->name, 253 ntohs(data->protocol)); 254 dev_kfree_skb_any(skb); 255 return NET_RX_DROP; 256 257 rx_error: 258 dev->stats.rx_errors++; /* Mark error */ 259 dev_kfree_skb_any(skb); 260 return NET_RX_DROP; 261 } 262 263 264 265 static void cisco_timer(unsigned long arg) 266 { 267 struct net_device *dev = (struct net_device *)arg; 268 hdlc_device *hdlc = dev_to_hdlc(dev); 269 struct cisco_state *st = state(hdlc); 270 271 spin_lock(&st->lock); 272 if (st->up && 273 time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) { 274 st->up = 0; 275 printk(KERN_INFO "%s: Link down\n", dev->name); 276 netif_dormant_on(dev); 277 } 278 279 cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq), 280 htonl(st->rxseq)); 281 spin_unlock(&st->lock); 282 283 st->timer.expires = jiffies + st->settings.interval * HZ; 284 st->timer.function = cisco_timer; 285 st->timer.data = arg; 286 add_timer(&st->timer); 287 } 288 289 290 291 static void cisco_start(struct net_device *dev) 292 { 293 hdlc_device *hdlc = dev_to_hdlc(dev); 294 struct cisco_state *st = state(hdlc); 295 unsigned long flags; 296 297 spin_lock_irqsave(&st->lock, flags); 298 st->up = st->txseq = st->rxseq = 0; 299 spin_unlock_irqrestore(&st->lock, flags); 300 301 init_timer(&st->timer); 302 st->timer.expires = jiffies + HZ; /* First poll after 1 s */ 303 st->timer.function = cisco_timer; 304 st->timer.data = (unsigned long)dev; 305 add_timer(&st->timer); 306 } 307 308 309 310 static void cisco_stop(struct net_device *dev) 311 { 312 hdlc_device *hdlc = dev_to_hdlc(dev); 313 struct cisco_state *st = state(hdlc); 314 unsigned long flags; 315 316 del_timer_sync(&st->timer); 317 318 spin_lock_irqsave(&st->lock, flags); 319 netif_dormant_on(dev); 320 st->up = st->txseq = 0; 321 spin_unlock_irqrestore(&st->lock, flags); 322 } 323 324 325 static struct hdlc_proto proto = { 326 .start = cisco_start, 327 .stop = cisco_stop, 328 .type_trans = cisco_type_trans, 329 .ioctl = cisco_ioctl, 330 .netif_rx = cisco_rx, 331 .module = THIS_MODULE, 332 }; 333 334 static const struct header_ops cisco_header_ops = { 335 .create = cisco_hard_header, 336 }; 337 338 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr) 339 { 340 cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco; 341 const size_t size = sizeof(cisco_proto); 342 cisco_proto new_settings; 343 hdlc_device *hdlc = dev_to_hdlc(dev); 344 int result; 345 346 switch (ifr->ifr_settings.type) { 347 case IF_GET_PROTO: 348 if (dev_to_hdlc(dev)->proto != &proto) 349 return -EINVAL; 350 ifr->ifr_settings.type = IF_PROTO_CISCO; 351 if (ifr->ifr_settings.size < size) { 352 ifr->ifr_settings.size = size; /* data size wanted */ 353 return -ENOBUFS; 354 } 355 if (copy_to_user(cisco_s, &state(hdlc)->settings, size)) 356 return -EFAULT; 357 return 0; 358 359 case IF_PROTO_CISCO: 360 if (!capable(CAP_NET_ADMIN)) 361 return -EPERM; 362 363 if (dev->flags & IFF_UP) 364 return -EBUSY; 365 366 if (copy_from_user(&new_settings, cisco_s, size)) 367 return -EFAULT; 368 369 if (new_settings.interval < 1 || 370 new_settings.timeout < 2) 371 return -EINVAL; 372 373 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT); 374 if (result) 375 return result; 376 377 result = attach_hdlc_protocol(dev, &proto, 378 sizeof(struct cisco_state)); 379 if (result) 380 return result; 381 382 memcpy(&state(hdlc)->settings, &new_settings, size); 383 spin_lock_init(&state(hdlc)->lock); 384 dev->header_ops = &cisco_header_ops; 385 dev->type = ARPHRD_CISCO; 386 netif_dormant_on(dev); 387 return 0; 388 } 389 390 return -EINVAL; 391 } 392 393 394 static int __init mod_init(void) 395 { 396 register_hdlc_protocol(&proto); 397 return 0; 398 } 399 400 401 402 static void __exit mod_exit(void) 403 { 404 unregister_hdlc_protocol(&proto); 405 } 406 407 408 module_init(mod_init); 409 module_exit(mod_exit); 410 411 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); 412 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC"); 413 MODULE_LICENSE("GPL v2"); 414