1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Generic HDLC support routines for Linux 4 * Cisco HDLC support 5 * 6 * Copyright (C) 2000 - 2006 Krzysztof Halasa <khc@pm.waw.pl> 7 */ 8 9 #include <linux/errno.h> 10 #include <linux/hdlc.h> 11 #include <linux/if_arp.h> 12 #include <linux/inetdevice.h> 13 #include <linux/init.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/pkt_sched.h> 17 #include <linux/poll.h> 18 #include <linux/rtnetlink.h> 19 #include <linux/skbuff.h> 20 21 #undef DEBUG_HARD_HEADER 22 23 #define CISCO_MULTICAST 0x8F /* Cisco multicast address */ 24 #define CISCO_UNICAST 0x0F /* Cisco unicast address */ 25 #define CISCO_KEEPALIVE 0x8035 /* Cisco keepalive protocol */ 26 #define CISCO_SYS_INFO 0x2000 /* Cisco interface/system info */ 27 #define CISCO_ADDR_REQ 0 /* Cisco address request */ 28 #define CISCO_ADDR_REPLY 1 /* Cisco address reply */ 29 #define CISCO_KEEPALIVE_REQ 2 /* Cisco keepalive request */ 30 31 32 struct hdlc_header { 33 u8 address; 34 u8 control; 35 __be16 protocol; 36 }__packed; 37 38 39 struct cisco_packet { 40 __be32 type; /* code */ 41 __be32 par1; 42 __be32 par2; 43 __be16 rel; /* reliability */ 44 __be32 time; 45 }__packed; 46 #define CISCO_PACKET_LEN 18 47 #define CISCO_BIG_PACKET_LEN 20 48 49 50 struct cisco_state { 51 cisco_proto settings; 52 53 struct timer_list timer; 54 struct net_device *dev; 55 spinlock_t lock; 56 unsigned long last_poll; 57 int up; 58 u32 txseq; /* TX sequence number, 0 = none */ 59 u32 rxseq; /* RX sequence number */ 60 }; 61 62 63 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr); 64 65 66 static inline struct cisco_state* state(hdlc_device *hdlc) 67 { 68 return (struct cisco_state *)hdlc->state; 69 } 70 71 72 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev, 73 u16 type, const void *daddr, const void *saddr, 74 unsigned int len) 75 { 76 struct hdlc_header *data; 77 #ifdef DEBUG_HARD_HEADER 78 printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name); 79 #endif 80 81 skb_push(skb, sizeof(struct hdlc_header)); 82 data = (struct hdlc_header*)skb->data; 83 if (type == CISCO_KEEPALIVE) 84 data->address = CISCO_MULTICAST; 85 else 86 data->address = CISCO_UNICAST; 87 data->control = 0; 88 data->protocol = htons(type); 89 90 return sizeof(struct hdlc_header); 91 } 92 93 94 95 static void cisco_keepalive_send(struct net_device *dev, u32 type, 96 __be32 par1, __be32 par2) 97 { 98 struct sk_buff *skb; 99 struct cisco_packet *data; 100 101 skb = dev_alloc_skb(sizeof(struct hdlc_header) + 102 sizeof(struct cisco_packet)); 103 if (!skb) { 104 netdev_warn(dev, "Memory squeeze on cisco_keepalive_send()\n"); 105 return; 106 } 107 skb_reserve(skb, 4); 108 cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0); 109 data = (struct cisco_packet*)(skb->data + 4); 110 111 data->type = htonl(type); 112 data->par1 = par1; 113 data->par2 = par2; 114 data->rel = cpu_to_be16(0xFFFF); 115 /* we will need do_div here if 1000 % HZ != 0 */ 116 data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ)); 117 118 skb_put(skb, sizeof(struct cisco_packet)); 119 skb->priority = TC_PRIO_CONTROL; 120 skb->dev = dev; 121 skb_reset_network_header(skb); 122 123 dev_queue_xmit(skb); 124 } 125 126 127 128 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev) 129 { 130 struct hdlc_header *data = (struct hdlc_header*)skb->data; 131 132 if (skb->len < sizeof(struct hdlc_header)) 133 return cpu_to_be16(ETH_P_HDLC); 134 135 if (data->address != CISCO_MULTICAST && 136 data->address != CISCO_UNICAST) 137 return cpu_to_be16(ETH_P_HDLC); 138 139 switch (data->protocol) { 140 case cpu_to_be16(ETH_P_IP): 141 case cpu_to_be16(ETH_P_IPX): 142 case cpu_to_be16(ETH_P_IPV6): 143 skb_pull(skb, sizeof(struct hdlc_header)); 144 return data->protocol; 145 default: 146 return cpu_to_be16(ETH_P_HDLC); 147 } 148 } 149 150 151 static int cisco_rx(struct sk_buff *skb) 152 { 153 struct net_device *dev = skb->dev; 154 hdlc_device *hdlc = dev_to_hdlc(dev); 155 struct cisco_state *st = state(hdlc); 156 struct hdlc_header *data = (struct hdlc_header*)skb->data; 157 struct cisco_packet *cisco_data; 158 struct in_device *in_dev; 159 __be32 addr, mask; 160 u32 ack; 161 162 if (skb->len < sizeof(struct hdlc_header)) 163 goto rx_error; 164 165 if (data->address != CISCO_MULTICAST && 166 data->address != CISCO_UNICAST) 167 goto rx_error; 168 169 switch (ntohs(data->protocol)) { 170 case CISCO_SYS_INFO: 171 /* Packet is not needed, drop it. */ 172 dev_kfree_skb_any(skb); 173 return NET_RX_SUCCESS; 174 175 case CISCO_KEEPALIVE: 176 if ((skb->len != sizeof(struct hdlc_header) + 177 CISCO_PACKET_LEN) && 178 (skb->len != sizeof(struct hdlc_header) + 179 CISCO_BIG_PACKET_LEN)) { 180 netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n", 181 skb->len); 182 goto rx_error; 183 } 184 185 cisco_data = (struct cisco_packet*)(skb->data + sizeof 186 (struct hdlc_header)); 187 188 switch (ntohl (cisco_data->type)) { 189 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */ 190 rcu_read_lock(); 191 in_dev = __in_dev_get_rcu(dev); 192 addr = 0; 193 mask = ~cpu_to_be32(0); /* is the mask correct? */ 194 195 if (in_dev != NULL) { 196 const struct in_ifaddr *ifa; 197 198 in_dev_for_each_ifa_rcu(ifa, in_dev) { 199 if (strcmp(dev->name, 200 ifa->ifa_label) == 0) { 201 addr = ifa->ifa_local; 202 mask = ifa->ifa_mask; 203 break; 204 } 205 } 206 207 cisco_keepalive_send(dev, CISCO_ADDR_REPLY, 208 addr, mask); 209 } 210 rcu_read_unlock(); 211 dev_kfree_skb_any(skb); 212 return NET_RX_SUCCESS; 213 214 case CISCO_ADDR_REPLY: 215 netdev_info(dev, "Unexpected Cisco IP address reply\n"); 216 goto rx_error; 217 218 case CISCO_KEEPALIVE_REQ: 219 spin_lock(&st->lock); 220 st->rxseq = ntohl(cisco_data->par1); 221 ack = ntohl(cisco_data->par2); 222 if (ack && (ack == st->txseq || 223 /* our current REQ may be in transit */ 224 ack == st->txseq - 1)) { 225 st->last_poll = jiffies; 226 if (!st->up) { 227 u32 sec, min, hrs, days; 228 sec = ntohl(cisco_data->time) / 1000; 229 min = sec / 60; sec -= min * 60; 230 hrs = min / 60; min -= hrs * 60; 231 days = hrs / 24; hrs -= days * 24; 232 netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n", 233 days, hrs, min, sec); 234 netif_dormant_off(dev); 235 st->up = 1; 236 } 237 } 238 spin_unlock(&st->lock); 239 240 dev_kfree_skb_any(skb); 241 return NET_RX_SUCCESS; 242 } /* switch (keepalive type) */ 243 } /* switch (protocol) */ 244 245 netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol)); 246 dev_kfree_skb_any(skb); 247 return NET_RX_DROP; 248 249 rx_error: 250 dev->stats.rx_errors++; /* Mark error */ 251 dev_kfree_skb_any(skb); 252 return NET_RX_DROP; 253 } 254 255 256 257 static void cisco_timer(struct timer_list *t) 258 { 259 struct cisco_state *st = from_timer(st, t, timer); 260 struct net_device *dev = st->dev; 261 262 spin_lock(&st->lock); 263 if (st->up && 264 time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) { 265 st->up = 0; 266 netdev_info(dev, "Link down\n"); 267 netif_dormant_on(dev); 268 } 269 270 cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq), 271 htonl(st->rxseq)); 272 spin_unlock(&st->lock); 273 274 st->timer.expires = jiffies + st->settings.interval * HZ; 275 add_timer(&st->timer); 276 } 277 278 279 280 static void cisco_start(struct net_device *dev) 281 { 282 hdlc_device *hdlc = dev_to_hdlc(dev); 283 struct cisco_state *st = state(hdlc); 284 unsigned long flags; 285 286 spin_lock_irqsave(&st->lock, flags); 287 st->up = st->txseq = st->rxseq = 0; 288 spin_unlock_irqrestore(&st->lock, flags); 289 290 st->dev = dev; 291 timer_setup(&st->timer, cisco_timer, 0); 292 st->timer.expires = jiffies + HZ; /* First poll after 1 s */ 293 add_timer(&st->timer); 294 } 295 296 297 298 static void cisco_stop(struct net_device *dev) 299 { 300 hdlc_device *hdlc = dev_to_hdlc(dev); 301 struct cisco_state *st = state(hdlc); 302 unsigned long flags; 303 304 del_timer_sync(&st->timer); 305 306 spin_lock_irqsave(&st->lock, flags); 307 netif_dormant_on(dev); 308 st->up = st->txseq = 0; 309 spin_unlock_irqrestore(&st->lock, flags); 310 } 311 312 313 static struct hdlc_proto proto = { 314 .start = cisco_start, 315 .stop = cisco_stop, 316 .type_trans = cisco_type_trans, 317 .ioctl = cisco_ioctl, 318 .netif_rx = cisco_rx, 319 .module = THIS_MODULE, 320 }; 321 322 static const struct header_ops cisco_header_ops = { 323 .create = cisco_hard_header, 324 }; 325 326 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr) 327 { 328 cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco; 329 const size_t size = sizeof(cisco_proto); 330 cisco_proto new_settings; 331 hdlc_device *hdlc = dev_to_hdlc(dev); 332 int result; 333 334 switch (ifr->ifr_settings.type) { 335 case IF_GET_PROTO: 336 if (dev_to_hdlc(dev)->proto != &proto) 337 return -EINVAL; 338 ifr->ifr_settings.type = IF_PROTO_CISCO; 339 if (ifr->ifr_settings.size < size) { 340 ifr->ifr_settings.size = size; /* data size wanted */ 341 return -ENOBUFS; 342 } 343 if (copy_to_user(cisco_s, &state(hdlc)->settings, size)) 344 return -EFAULT; 345 return 0; 346 347 case IF_PROTO_CISCO: 348 if (!capable(CAP_NET_ADMIN)) 349 return -EPERM; 350 351 if (dev->flags & IFF_UP) 352 return -EBUSY; 353 354 if (copy_from_user(&new_settings, cisco_s, size)) 355 return -EFAULT; 356 357 if (new_settings.interval < 1 || 358 new_settings.timeout < 2) 359 return -EINVAL; 360 361 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT); 362 if (result) 363 return result; 364 365 result = attach_hdlc_protocol(dev, &proto, 366 sizeof(struct cisco_state)); 367 if (result) 368 return result; 369 370 memcpy(&state(hdlc)->settings, &new_settings, size); 371 spin_lock_init(&state(hdlc)->lock); 372 dev->header_ops = &cisco_header_ops; 373 dev->type = ARPHRD_CISCO; 374 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev); 375 netif_dormant_on(dev); 376 return 0; 377 } 378 379 return -EINVAL; 380 } 381 382 383 static int __init mod_init(void) 384 { 385 register_hdlc_protocol(&proto); 386 return 0; 387 } 388 389 390 391 static void __exit mod_exit(void) 392 { 393 unregister_hdlc_protocol(&proto); 394 } 395 396 397 module_init(mod_init); 398 module_exit(mod_exit); 399 400 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); 401 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC"); 402 MODULE_LICENSE("GPL v2"); 403