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 netdev_warn(dev, "Memory squeeze on cisco_keepalive_send()\n"); 107 return; 108 } 109 skb_reserve(skb, 4); 110 cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0); 111 data = (struct cisco_packet*)(skb->data + 4); 112 113 data->type = htonl(type); 114 data->par1 = par1; 115 data->par2 = par2; 116 data->rel = cpu_to_be16(0xFFFF); 117 /* we will need do_div here if 1000 % HZ != 0 */ 118 data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ)); 119 120 skb_put(skb, sizeof(struct cisco_packet)); 121 skb->priority = TC_PRIO_CONTROL; 122 skb->dev = dev; 123 skb_reset_network_header(skb); 124 125 dev_queue_xmit(skb); 126 } 127 128 129 130 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev) 131 { 132 struct hdlc_header *data = (struct hdlc_header*)skb->data; 133 134 if (skb->len < sizeof(struct hdlc_header)) 135 return cpu_to_be16(ETH_P_HDLC); 136 137 if (data->address != CISCO_MULTICAST && 138 data->address != CISCO_UNICAST) 139 return cpu_to_be16(ETH_P_HDLC); 140 141 switch (data->protocol) { 142 case cpu_to_be16(ETH_P_IP): 143 case cpu_to_be16(ETH_P_IPX): 144 case cpu_to_be16(ETH_P_IPV6): 145 skb_pull(skb, sizeof(struct hdlc_header)); 146 return data->protocol; 147 default: 148 return cpu_to_be16(ETH_P_HDLC); 149 } 150 } 151 152 153 static int cisco_rx(struct sk_buff *skb) 154 { 155 struct net_device *dev = skb->dev; 156 hdlc_device *hdlc = dev_to_hdlc(dev); 157 struct cisco_state *st = state(hdlc); 158 struct hdlc_header *data = (struct hdlc_header*)skb->data; 159 struct cisco_packet *cisco_data; 160 struct in_device *in_dev; 161 __be32 addr, mask; 162 u32 ack; 163 164 if (skb->len < sizeof(struct hdlc_header)) 165 goto rx_error; 166 167 if (data->address != CISCO_MULTICAST && 168 data->address != CISCO_UNICAST) 169 goto rx_error; 170 171 switch (ntohs(data->protocol)) { 172 case CISCO_SYS_INFO: 173 /* Packet is not needed, drop it. */ 174 dev_kfree_skb_any(skb); 175 return NET_RX_SUCCESS; 176 177 case CISCO_KEEPALIVE: 178 if ((skb->len != sizeof(struct hdlc_header) + 179 CISCO_PACKET_LEN) && 180 (skb->len != sizeof(struct hdlc_header) + 181 CISCO_BIG_PACKET_LEN)) { 182 netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n", 183 skb->len); 184 goto rx_error; 185 } 186 187 cisco_data = (struct cisco_packet*)(skb->data + sizeof 188 (struct hdlc_header)); 189 190 switch (ntohl (cisco_data->type)) { 191 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */ 192 rcu_read_lock(); 193 in_dev = __in_dev_get_rcu(dev); 194 addr = 0; 195 mask = ~cpu_to_be32(0); /* is the mask correct? */ 196 197 if (in_dev != NULL) { 198 struct in_ifaddr **ifap = &in_dev->ifa_list; 199 200 while (*ifap != NULL) { 201 if (strcmp(dev->name, 202 (*ifap)->ifa_label) == 0) { 203 addr = (*ifap)->ifa_local; 204 mask = (*ifap)->ifa_mask; 205 break; 206 } 207 ifap = &(*ifap)->ifa_next; 208 } 209 210 cisco_keepalive_send(dev, CISCO_ADDR_REPLY, 211 addr, mask); 212 } 213 rcu_read_unlock(); 214 dev_kfree_skb_any(skb); 215 return NET_RX_SUCCESS; 216 217 case CISCO_ADDR_REPLY: 218 netdev_info(dev, "Unexpected Cisco IP address reply\n"); 219 goto rx_error; 220 221 case CISCO_KEEPALIVE_REQ: 222 spin_lock(&st->lock); 223 st->rxseq = ntohl(cisco_data->par1); 224 ack = ntohl(cisco_data->par2); 225 if (ack && (ack == st->txseq || 226 /* our current REQ may be in transit */ 227 ack == st->txseq - 1)) { 228 st->last_poll = jiffies; 229 if (!st->up) { 230 u32 sec, min, hrs, days; 231 sec = ntohl(cisco_data->time) / 1000; 232 min = sec / 60; sec -= min * 60; 233 hrs = min / 60; min -= hrs * 60; 234 days = hrs / 24; hrs -= days * 24; 235 netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n", 236 days, hrs, min, sec); 237 netif_dormant_off(dev); 238 st->up = 1; 239 } 240 } 241 spin_unlock(&st->lock); 242 243 dev_kfree_skb_any(skb); 244 return NET_RX_SUCCESS; 245 } /* switch (keepalive type) */ 246 } /* switch (protocol) */ 247 248 netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol)); 249 dev_kfree_skb_any(skb); 250 return NET_RX_DROP; 251 252 rx_error: 253 dev->stats.rx_errors++; /* Mark error */ 254 dev_kfree_skb_any(skb); 255 return NET_RX_DROP; 256 } 257 258 259 260 static void cisco_timer(unsigned long arg) 261 { 262 struct net_device *dev = (struct net_device *)arg; 263 hdlc_device *hdlc = dev_to_hdlc(dev); 264 struct cisco_state *st = state(hdlc); 265 266 spin_lock(&st->lock); 267 if (st->up && 268 time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) { 269 st->up = 0; 270 netdev_info(dev, "Link down\n"); 271 netif_dormant_on(dev); 272 } 273 274 cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq), 275 htonl(st->rxseq)); 276 spin_unlock(&st->lock); 277 278 st->timer.expires = jiffies + st->settings.interval * HZ; 279 st->timer.function = cisco_timer; 280 st->timer.data = arg; 281 add_timer(&st->timer); 282 } 283 284 285 286 static void cisco_start(struct net_device *dev) 287 { 288 hdlc_device *hdlc = dev_to_hdlc(dev); 289 struct cisco_state *st = state(hdlc); 290 unsigned long flags; 291 292 spin_lock_irqsave(&st->lock, flags); 293 st->up = st->txseq = st->rxseq = 0; 294 spin_unlock_irqrestore(&st->lock, flags); 295 296 init_timer(&st->timer); 297 st->timer.expires = jiffies + HZ; /* First poll after 1 s */ 298 st->timer.function = cisco_timer; 299 st->timer.data = (unsigned long)dev; 300 add_timer(&st->timer); 301 } 302 303 304 305 static void cisco_stop(struct net_device *dev) 306 { 307 hdlc_device *hdlc = dev_to_hdlc(dev); 308 struct cisco_state *st = state(hdlc); 309 unsigned long flags; 310 311 del_timer_sync(&st->timer); 312 313 spin_lock_irqsave(&st->lock, flags); 314 netif_dormant_on(dev); 315 st->up = st->txseq = 0; 316 spin_unlock_irqrestore(&st->lock, flags); 317 } 318 319 320 static struct hdlc_proto proto = { 321 .start = cisco_start, 322 .stop = cisco_stop, 323 .type_trans = cisco_type_trans, 324 .ioctl = cisco_ioctl, 325 .netif_rx = cisco_rx, 326 .module = THIS_MODULE, 327 }; 328 329 static const struct header_ops cisco_header_ops = { 330 .create = cisco_hard_header, 331 }; 332 333 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr) 334 { 335 cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco; 336 const size_t size = sizeof(cisco_proto); 337 cisco_proto new_settings; 338 hdlc_device *hdlc = dev_to_hdlc(dev); 339 int result; 340 341 switch (ifr->ifr_settings.type) { 342 case IF_GET_PROTO: 343 if (dev_to_hdlc(dev)->proto != &proto) 344 return -EINVAL; 345 ifr->ifr_settings.type = IF_PROTO_CISCO; 346 if (ifr->ifr_settings.size < size) { 347 ifr->ifr_settings.size = size; /* data size wanted */ 348 return -ENOBUFS; 349 } 350 if (copy_to_user(cisco_s, &state(hdlc)->settings, size)) 351 return -EFAULT; 352 return 0; 353 354 case IF_PROTO_CISCO: 355 if (!capable(CAP_NET_ADMIN)) 356 return -EPERM; 357 358 if (dev->flags & IFF_UP) 359 return -EBUSY; 360 361 if (copy_from_user(&new_settings, cisco_s, size)) 362 return -EFAULT; 363 364 if (new_settings.interval < 1 || 365 new_settings.timeout < 2) 366 return -EINVAL; 367 368 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT); 369 if (result) 370 return result; 371 372 result = attach_hdlc_protocol(dev, &proto, 373 sizeof(struct cisco_state)); 374 if (result) 375 return result; 376 377 memcpy(&state(hdlc)->settings, &new_settings, size); 378 spin_lock_init(&state(hdlc)->lock); 379 dev->header_ops = &cisco_header_ops; 380 dev->type = ARPHRD_CISCO; 381 netif_dormant_on(dev); 382 return 0; 383 } 384 385 return -EINVAL; 386 } 387 388 389 static int __init mod_init(void) 390 { 391 register_hdlc_protocol(&proto); 392 return 0; 393 } 394 395 396 397 static void __exit mod_exit(void) 398 { 399 unregister_hdlc_protocol(&proto); 400 } 401 402 403 module_init(mod_init); 404 module_exit(mod_exit); 405 406 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); 407 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC"); 408 MODULE_LICENSE("GPL v2"); 409