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