drivers/net/wan/hdlc_ppp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic HDLC support routines for Linux
   4  * Point-to-point protocol support
   5  *
   6  * Copyright (C) 1999 - 2008 Krzysztof Halasa <[email protected]>
   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/skbuff.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21
  22 #define DEBUG_CP                0 /* also bytes# to dump */
  23 #define DEBUG_STATE             0
  24 #define DEBUG_HARD_HEADER       0
  25
  26 #define HDLC_ADDR_ALLSTATIONS   0xFF
  27 #define HDLC_CTRL_UI            0x03
  28
  29 #define PID_LCP                 0xC021
  30 #define PID_IP                  0x0021
  31 #define PID_IPCP                0x8021
  32 #define PID_IPV6                0x0057
  33 #define PID_IPV6CP              0x8057
  34
  35 enum {IDX_LCP = 0, IDX_IPCP, IDX_IPV6CP, IDX_COUNT};
  36 enum {CP_CONF_REQ = 1, CP_CONF_ACK, CP_CONF_NAK, CP_CONF_REJ, CP_TERM_REQ,
  37       CP_TERM_ACK, CP_CODE_REJ, LCP_PROTO_REJ, LCP_ECHO_REQ, LCP_ECHO_REPLY,
  38       LCP_DISC_REQ, CP_CODES};
  39 #if DEBUG_CP
  40 static const char *const code_names[CP_CODES] = {
  41         "0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
  42         "TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
  43 };
  44
  45 static char debug_buffer[64 + 3 * DEBUG_CP];
  46 #endif
  47
  48 enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
  49
  50 struct hdlc_header {
  51         u8 address;
  52         u8 control;
  53         __be16 protocol;
  54 };
  55
  56 struct cp_header {
  57         u8 code;
  58         u8 id;
  59         __be16 len;
  60 };
  61
  62 struct proto {
  63         struct net_device *dev;
  64         struct timer_list timer;
  65         unsigned long timeout;
  66         u16 pid;                /* protocol ID */
  67         u8 state;
  68         u8 cr_id;               /* ID of last Configuration-Request */
  69         u8 restart_counter;
  70 };
  71
  72 struct ppp {
  73         struct proto protos[IDX_COUNT];
  74         spinlock_t lock;
  75         unsigned long last_pong;
  76         unsigned int req_timeout, cr_retries, term_retries;
  77         unsigned int keepalive_interval, keepalive_timeout;
  78         u8 seq;                 /* local sequence number for requests */
  79         u8 echo_id;             /* ID of last Echo-Request (LCP) */
  80 };
  81
  82 enum {CLOSED = 0, STOPPED, STOPPING, REQ_SENT, ACK_RECV, ACK_SENT, OPENED,
  83       STATES, STATE_MASK = 0xF};
  84 enum {START = 0, STOP, TO_GOOD, TO_BAD, RCR_GOOD, RCR_BAD, RCA, RCN, RTR, RTA,
  85       RUC, RXJ_GOOD, RXJ_BAD, EVENTS};
  86 enum {INV = 0x10, IRC = 0x20, ZRC = 0x40, SCR = 0x80, SCA = 0x100,
  87       SCN = 0x200, STR = 0x400, STA = 0x800, SCJ = 0x1000};
  88
  89 #if DEBUG_STATE
  90 static const char *const state_names[STATES] = {
  91         "Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
  92         "Opened"
  93 };
  94
  95 static const char *const event_names[EVENTS] = {
  96         "Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
  97         "RTR", "RTA", "RUC", "RXJ+", "RXJ-"
  98 };
  99 #endif
 100
 101 static struct sk_buff_head tx_queue; /* used when holding the spin lock */
 102
 103 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
 104
 105 static inline struct ppp *get_ppp(struct net_device *dev)
 106 {
 107         return (struct ppp *)dev_to_hdlc(dev)->state;
 108 }
 109
 110 static inline struct proto *get_proto(struct net_device *dev, u16 pid)
 111 {
 112         struct ppp *ppp = get_ppp(dev);
 113
 114         switch (pid) {
 115         case PID_LCP:
 116                 return &ppp->protos[IDX_LCP];
 117         case PID_IPCP:
 118                 return &ppp->protos[IDX_IPCP];
 119         case PID_IPV6CP:
 120                 return &ppp->protos[IDX_IPV6CP];
 121         default:
 122                 return NULL;
 123         }
 124 }
 125
 126 static inline const char *proto_name(u16 pid)
 127 {
 128         switch (pid) {
 129         case PID_LCP:
 130                 return "LCP";
 131         case PID_IPCP:
 132                 return "IPCP";
 133         case PID_IPV6CP:
 134                 return "IPV6CP";
 135         default:
 136                 return NULL;
 137         }
 138 }
 139
 140 static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
 141 {
 142         struct hdlc_header *data = (struct hdlc_header *)skb->data;
 143
 144         if (skb->len < sizeof(struct hdlc_header))
 145                 return htons(ETH_P_HDLC);
 146         if (data->address != HDLC_ADDR_ALLSTATIONS ||
 147             data->control != HDLC_CTRL_UI)
 148                 return htons(ETH_P_HDLC);
 149
 150         switch (data->protocol) {
 151         case cpu_to_be16(PID_IP):
 152                 skb_pull(skb, sizeof(struct hdlc_header));
 153                 return htons(ETH_P_IP);
 154
 155         case cpu_to_be16(PID_IPV6):
 156                 skb_pull(skb, sizeof(struct hdlc_header));
 157                 return htons(ETH_P_IPV6);
 158
 159         default:
 160                 return htons(ETH_P_HDLC);
 161         }
 162 }
 163
 164 static int ppp_hard_header(struct sk_buff *skb, struct net_device *dev,
 165                            u16 type, const void *daddr, const void *saddr,
 166                            unsigned int len)
 167 {
 168         struct hdlc_header *data;
 169 #if DEBUG_HARD_HEADER
 170         printk(KERN_DEBUG "%s: ppp_hard_header() called\n", dev->name);
 171 #endif
 172
 173         skb_push(skb, sizeof(struct hdlc_header));
 174         data = (struct hdlc_header *)skb->data;
 175
 176         data->address = HDLC_ADDR_ALLSTATIONS;
 177         data->control = HDLC_CTRL_UI;
 178         switch (type) {
 179         case ETH_P_IP:
 180                 data->protocol = htons(PID_IP);
 181                 break;
 182         case ETH_P_IPV6:
 183                 data->protocol = htons(PID_IPV6);
 184                 break;
 185         case PID_LCP:
 186         case PID_IPCP:
 187         case PID_IPV6CP:
 188                 data->protocol = htons(type);
 189                 break;
 190         default:                /* unknown protocol */
 191                 data->protocol = 0;
 192         }
 193         return sizeof(struct hdlc_header);
 194 }
 195
 196 static void ppp_tx_flush(void)
 197 {
 198         struct sk_buff *skb;
 199
 200         while ((skb = skb_dequeue(&tx_queue)) != NULL)
 201                 dev_queue_xmit(skb);
 202 }
 203
 204 static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
 205                       u8 id, unsigned int len, const void *data)
 206 {
 207         struct sk_buff *skb;
 208         struct cp_header *cp;
 209         unsigned int magic_len = 0;
 210         static u32 magic;
 211
 212 #if DEBUG_CP
 213         int i;
 214         char *ptr;
 215 #endif
 216
 217         if (pid == PID_LCP && (code == LCP_ECHO_REQ || code == LCP_ECHO_REPLY))
 218                 magic_len = sizeof(magic);
 219
 220         skb = dev_alloc_skb(sizeof(struct hdlc_header) +
 221                             sizeof(struct cp_header) + magic_len + len);
 222         if (!skb)
 223                 return;
 224
 225         skb_reserve(skb, sizeof(struct hdlc_header));
 226
 227         cp = skb_put(skb, sizeof(struct cp_header));
 228         cp->code = code;
 229         cp->id = id;
 230         cp->len = htons(sizeof(struct cp_header) + magic_len + len);
 231
 232         if (magic_len)
 233                 skb_put_data(skb, &magic, magic_len);
 234         if (len)
 235                 skb_put_data(skb, data, len);
 236
 237 #if DEBUG_CP
 238         BUG_ON(code >= CP_CODES);
 239         ptr = debug_buffer;
 240         *ptr = '\x0';
 241         for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
 242                 sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
 243                 ptr += strlen(ptr);
 244         }
 245         printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
 246                proto_name(pid), code_names[code], id, debug_buffer);
 247 #endif
 248
 249         ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
 250
 251         skb->priority = TC_PRIO_CONTROL;
 252         skb->dev = dev;
 253         skb->protocol = htons(ETH_P_HDLC);
 254         skb_reset_network_header(skb);
 255         skb_queue_tail(&tx_queue, skb);
 256 }
 257
 258 /* State transition table (compare STD-51)
 259    Events                                   Actions
 260    TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
 261    TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
 262
 263    RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
 264    RCR- = Receive-Configure-Request (Bad)
 265    RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
 266    RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
 267
 268    RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
 269    RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
 270
 271    RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
 272    RXJ+ = Receive-Code-Reject (permitted)
 273        or Receive-Protocol-Reject
 274    RXJ- = Receive-Code-Reject (catastrophic)
 275        or Receive-Protocol-Reject
 276 */
 277 static int cp_table[EVENTS][STATES] = {
 278         /* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
 279              0           1         2       3       4      5          6    */
 280         {IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
 281         {   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
 282         {   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
 283         {   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
 284         {  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
 285         {  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
 286         {  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
 287         {  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
 288         {  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
 289         {    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
 290         {  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
 291         {    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
 292         {    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
 293 };
 294
 295 /* SCA: RCR+ must supply id, len and data
 296    SCN: RCR- must supply code, id, len and data
 297    STA: RTR must supply id
 298    SCJ: RUC must supply CP packet len and data */
 299 static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
 300                          u8 id, unsigned int len, const void *data)
 301 {
 302         int old_state, action;
 303         struct ppp *ppp = get_ppp(dev);
 304         struct proto *proto = get_proto(dev, pid);
 305
 306         old_state = proto->state;
 307         BUG_ON(old_state >= STATES);
 308         BUG_ON(event >= EVENTS);
 309
 310 #if DEBUG_STATE
 311         printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
 312                proto_name(pid), event_names[event], state_names[proto->state]);
 313 #endif
 314
 315         action = cp_table[event][old_state];
 316
 317         proto->state = action & STATE_MASK;
 318         if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
 319                 mod_timer(&proto->timer, proto->timeout =
 320                           jiffies + ppp->req_timeout * HZ);
 321         if (action & ZRC)
 322                 proto->restart_counter = 0;
 323         if (action & IRC)
 324                 proto->restart_counter = (proto->state == STOPPING) ?
 325                         ppp->term_retries : ppp->cr_retries;
 326
 327         if (action & SCR)       /* send Configure-Request */
 328                 ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
 329                           0, NULL);
 330         if (action & SCA)       /* send Configure-Ack */
 331                 ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
 332         if (action & SCN)       /* send Configure-Nak/Reject */
 333                 ppp_tx_cp(dev, pid, code, id, len, data);
 334         if (action & STR)       /* send Terminate-Request */
 335                 ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
 336         if (action & STA)       /* send Terminate-Ack */
 337                 ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
 338         if (action & SCJ)       /* send Code-Reject */
 339                 ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
 340
 341         if (old_state != OPENED && proto->state == OPENED) {
 342                 netdev_info(dev, "%s up\n", proto_name(pid));
 343                 if (pid == PID_LCP) {
 344                         netif_dormant_off(dev);
 345                         ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
 346                         ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
 347                         ppp->last_pong = jiffies;
 348                         mod_timer(&proto->timer, proto->timeout =
 349                                   jiffies + ppp->keepalive_interval * HZ);
 350                 }
 351         }
 352         if (old_state == OPENED && proto->state != OPENED) {
 353                 netdev_info(dev, "%s down\n", proto_name(pid));
 354                 if (pid == PID_LCP) {
 355                         netif_dormant_on(dev);
 356                         ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
 357                         ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
 358                 }
 359         }
 360         if (old_state != CLOSED && proto->state == CLOSED)
 361                 del_timer(&proto->timer);
 362
 363 #if DEBUG_STATE
 364         printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
 365                proto_name(pid), event_names[event], state_names[proto->state]);
 366 #endif
 367 }
 368
 369 static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
 370                             unsigned int req_len, const u8 *data)
 371 {
 372         static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
 373         const u8 *opt;
 374         u8 *out;
 375         unsigned int len = req_len, nak_len = 0, rej_len = 0;
 376
 377         out = kmalloc(len, GFP_ATOMIC);
 378         if (!out) {
 379                 dev->stats.rx_dropped++;
 380                 return; /* out of memory, ignore CR packet */
 381         }
 382
 383         for (opt = data; len; len -= opt[1], opt += opt[1]) {
 384                 if (len < 2 || opt[1] < 2 || len < opt[1])
 385                         goto err_out;
 386
 387                 if (pid == PID_LCP)
 388                         switch (opt[0]) {
 389                         case LCP_OPTION_MRU:
 390                                 continue; /* MRU always OK and > 1500 bytes? */
 391
 392                         case LCP_OPTION_ACCM: /* async control character map */
 393                                 if (opt[1] < sizeof(valid_accm))
 394                                         goto err_out;
 395                                 if (!memcmp(opt, valid_accm,
 396                                             sizeof(valid_accm)))
 397                                         continue;
 398                                 if (!rej_len) { /* NAK it */
 399                                         memcpy(out + nak_len, valid_accm,
 400                                                sizeof(valid_accm));
 401                                         nak_len += sizeof(valid_accm);
 402                                         continue;
 403                                 }
 404                                 break;
 405                         case LCP_OPTION_MAGIC:
 406                                 if (len < 6)
 407                                         goto err_out;
 408                                 if (opt[1] != 6 || (!opt[2] && !opt[3] &&
 409                                                     !opt[4] && !opt[5]))
 410                                         break; /* reject invalid magic number */
 411                                 continue;
 412                         }
 413                 /* reject this option */
 414                 memcpy(out + rej_len, opt, opt[1]);
 415                 rej_len += opt[1];
 416         }
 417
 418         if (rej_len)
 419                 ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
 420         else if (nak_len)
 421                 ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
 422         else
 423                 ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
 424
 425         kfree(out);
 426         return;
 427
 428 err_out:
 429         dev->stats.rx_errors++;
 430         kfree(out);
 431 }
 432
 433 static int ppp_rx(struct sk_buff *skb)
 434 {
 435         struct hdlc_header *hdr = (struct hdlc_header *)skb->data;
 436         struct net_device *dev = skb->dev;
 437         struct ppp *ppp = get_ppp(dev);
 438         struct proto *proto;
 439         struct cp_header *cp;
 440         unsigned long flags;
 441         unsigned int len;
 442         u16 pid;
 443 #if DEBUG_CP
 444         int i;
 445         char *ptr;
 446 #endif
 447
 448         spin_lock_irqsave(&ppp->lock, flags);
 449         /* Check HDLC header */
 450         if (skb->len < sizeof(struct hdlc_header))
 451                 goto rx_error;
 452         cp = skb_pull(skb, sizeof(struct hdlc_header));
 453         if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
 454             hdr->control != HDLC_CTRL_UI)
 455                 goto rx_error;
 456
 457         pid = ntohs(hdr->protocol);
 458         proto = get_proto(dev, pid);
 459         if (!proto) {
 460                 if (ppp->protos[IDX_LCP].state == OPENED)
 461                         ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
 462                                   ++ppp->seq, skb->len + 2, &hdr->protocol);
 463                 goto rx_error;
 464         }
 465
 466         len = ntohs(cp->len);
 467         if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
 468             skb->len < len /* truncated packet? */)
 469                 goto rx_error;
 470         skb_pull(skb, sizeof(struct cp_header));
 471         len -= sizeof(struct cp_header);
 472
 473         /* HDLC and CP headers stripped from skb */
 474 #if DEBUG_CP
 475         if (cp->code < CP_CODES)
 476                 sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
 477                         cp->id);
 478         else
 479                 sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
 480         ptr = debug_buffer + strlen(debug_buffer);
 481         for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
 482                 sprintf(ptr, " %02X", skb->data[i]);
 483                 ptr += strlen(ptr);
 484         }
 485         printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
 486                debug_buffer);
 487 #endif
 488
 489         /* LCP only */
 490         if (pid == PID_LCP)
 491                 switch (cp->code) {
 492                 case LCP_PROTO_REJ:
 493                         pid = ntohs(*(__be16 *)skb->data);
 494                         if (pid == PID_LCP || pid == PID_IPCP ||
 495                             pid == PID_IPV6CP)
 496                                 ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
 497                                              0, NULL);
 498                         goto out;
 499
 500                 case LCP_ECHO_REQ: /* send Echo-Reply */
 501                         if (len >= 4 && proto->state == OPENED)
 502                                 ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
 503                                           cp->id, len - 4, skb->data + 4);
 504                         goto out;
 505
 506                 case LCP_ECHO_REPLY:
 507                         if (cp->id == ppp->echo_id)
 508                                 ppp->last_pong = jiffies;
 509                         goto out;
 510
 511                 case LCP_DISC_REQ: /* discard */
 512                         goto out;
 513                 }
 514
 515         /* LCP, IPCP and IPV6CP */
 516         switch (cp->code) {
 517         case CP_CONF_REQ:
 518                 ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
 519                 break;
 520
 521         case CP_CONF_ACK:
 522                 if (cp->id == proto->cr_id)
 523                         ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
 524                 break;
 525
 526         case CP_CONF_REJ:
 527         case CP_CONF_NAK:
 528                 if (cp->id == proto->cr_id)
 529                         ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
 530                 break;
 531
 532         case CP_TERM_REQ:
 533                 ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
 534                 break;
 535
 536         case CP_TERM_ACK:
 537                 ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
 538                 break;
 539
 540         case CP_CODE_REJ:
 541                 ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
 542                 break;
 543
 544         default:
 545                 len += sizeof(struct cp_header);
 546                 if (len > dev->mtu)
 547                         len = dev->mtu;
 548                 ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
 549                 break;
 550         }
 551         goto out;
 552
 553 rx_error:
 554         dev->stats.rx_errors++;
 555 out:
 556         spin_unlock_irqrestore(&ppp->lock, flags);
 557         dev_kfree_skb_any(skb);
 558         ppp_tx_flush();
 559         return NET_RX_DROP;
 560 }
 561
 562 static void ppp_timer(struct timer_list *t)
 563 {
 564         struct proto *proto = from_timer(proto, t, timer);
 565         struct ppp *ppp = get_ppp(proto->dev);
 566         unsigned long flags;
 567
 568         spin_lock_irqsave(&ppp->lock, flags);
 569         /* mod_timer could be called after we entered this function but
 570          * before we got the lock.
 571          */
 572         if (timer_pending(&proto->timer)) {
 573                 spin_unlock_irqrestore(&ppp->lock, flags);
 574                 return;
 575         }
 576         switch (proto->state) {
 577         case STOPPING:
 578         case REQ_SENT:
 579         case ACK_RECV:
 580         case ACK_SENT:
 581                 if (proto->restart_counter) {
 582                         ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 583                                      0, NULL);
 584                         proto->restart_counter--;
 585                 } else if (netif_carrier_ok(proto->dev))
 586                         ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 587                                      0, NULL);
 588                 else
 589                         ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
 590                                      0, NULL);
 591                 break;
 592
 593         case OPENED:
 594                 if (proto->pid != PID_LCP)
 595                         break;
 596                 if (time_after(jiffies, ppp->last_pong +
 597                                ppp->keepalive_timeout * HZ)) {
 598                         netdev_info(proto->dev, "Link down\n");
 599                         ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
 600                         ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
 601                 } else {        /* send keep-alive packet */
 602                         ppp->echo_id = ++ppp->seq;
 603                         ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
 604                                   ppp->echo_id, 0, NULL);
 605                         proto->timer.expires = jiffies +
 606                                 ppp->keepalive_interval * HZ;
 607                         add_timer(&proto->timer);
 608                 }
 609                 break;
 610         }
 611         spin_unlock_irqrestore(&ppp->lock, flags);
 612         ppp_tx_flush();
 613 }
 614
 615 static void ppp_start(struct net_device *dev)
 616 {
 617         struct ppp *ppp = get_ppp(dev);
 618         int i;
 619
 620         for (i = 0; i < IDX_COUNT; i++) {
 621                 struct proto *proto = &ppp->protos[i];
 622
 623                 proto->dev = dev;
 624                 timer_setup(&proto->timer, ppp_timer, 0);
 625                 proto->state = CLOSED;
 626         }
 627         ppp->protos[IDX_LCP].pid = PID_LCP;
 628         ppp->protos[IDX_IPCP].pid = PID_IPCP;
 629         ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
 630
 631         ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
 632 }
 633
 634 static void ppp_stop(struct net_device *dev)
 635 {
 636         ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
 637 }
 638
 639 static void ppp_close(struct net_device *dev)
 640 {
 641         ppp_tx_flush();
 642 }
 643
 644 static struct hdlc_proto proto = {
 645         .start          = ppp_start,
 646         .stop           = ppp_stop,
 647         .close          = ppp_close,
 648         .type_trans     = ppp_type_trans,
 649         .ioctl          = ppp_ioctl,
 650         .netif_rx       = ppp_rx,
 651         .module         = THIS_MODULE,
 652 };
 653
 654 static const struct header_ops ppp_header_ops = {
 655         .create = ppp_hard_header,
 656 };
 657
 658 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr)
 659 {
 660         hdlc_device *hdlc = dev_to_hdlc(dev);
 661         struct ppp *ppp;
 662         int result;
 663
 664         switch (ifr->ifr_settings.type) {
 665         case IF_GET_PROTO:
 666                 if (dev_to_hdlc(dev)->proto != &proto)
 667                         return -EINVAL;
 668                 ifr->ifr_settings.type = IF_PROTO_PPP;
 669                 return 0; /* return protocol only, no settable parameters */
 670
 671         case IF_PROTO_PPP:
 672                 if (!capable(CAP_NET_ADMIN))
 673                         return -EPERM;
 674
 675                 if (dev->flags & IFF_UP)
 676                         return -EBUSY;
 677
 678                 /* no settable parameters */
 679
 680                 result = hdlc->attach(dev, ENCODING_NRZ,
 681                                       PARITY_CRC16_PR1_CCITT);
 682                 if (result)
 683                         return result;
 684
 685                 result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
 686                 if (result)
 687                         return result;
 688
 689                 ppp = get_ppp(dev);
 690                 spin_lock_init(&ppp->lock);
 691                 ppp->req_timeout = 2;
 692                 ppp->cr_retries = 10;
 693                 ppp->term_retries = 2;
 694                 ppp->keepalive_interval = 10;
 695                 ppp->keepalive_timeout = 60;
 696
 697                 dev->hard_header_len = sizeof(struct hdlc_header);
 698                 dev->header_ops = &ppp_header_ops;
 699                 dev->type = ARPHRD_PPP;
 700                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 701                 netif_dormant_on(dev);
 702                 return 0;
 703         }
 704
 705         return -EINVAL;
 706 }
 707
 708 static int __init mod_init(void)
 709 {
 710         skb_queue_head_init(&tx_queue);
 711         register_hdlc_protocol(&proto);
 712         return 0;
 713 }
 714
 715 static void __exit mod_exit(void)
 716 {
 717         unregister_hdlc_protocol(&proto);
 718 }
 719
 720 module_init(mod_init);
 721 module_exit(mod_exit);
 722
 723 MODULE_AUTHOR("Krzysztof Halasa <[email protected]>");
 724 MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
 725 MODULE_LICENSE("GPL v2");