drivers/net/wan/hdlc_ppp.c

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