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