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 static char debug_buffer[64 + 3 * DEBUG_CP];
  45 #endif
  46
  47 enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
  48
  49 struct hdlc_header {
  50         u8 address;
  51         u8 control;
  52         __be16 protocol;
  53 };
  54
  55 struct cp_header {
  56         u8 code;
  57         u8 id;
  58         __be16 len;
  59 };
  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 static const char *const event_names[EVENTS] = {
  95         "Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
  96         "RTR", "RTA", "RUC", "RXJ+", "RXJ-"
  97 };
  98 #endif
  99
 100 static struct sk_buff_head tx_queue; /* used when holding the spin lock */
 101
 102 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
 103
 104 static inline struct ppp* get_ppp(struct net_device *dev)
 105 {
 106         return (struct ppp *)dev_to_hdlc(dev)->state;
 107 }
 108
 109 static inline struct proto* get_proto(struct net_device *dev, u16 pid)
 110 {
 111         struct ppp *ppp = get_ppp(dev);
 112
 113         switch (pid) {
 114         case PID_LCP:
 115                 return &ppp->protos[IDX_LCP];
 116         case PID_IPCP:
 117                 return &ppp->protos[IDX_IPCP];
 118         case PID_IPV6CP:
 119                 return &ppp->protos[IDX_IPV6CP];
 120         default:
 121                 return NULL;
 122         }
 123 }
 124
 125 static inline const char* proto_name(u16 pid)
 126 {
 127         switch (pid) {
 128         case PID_LCP:
 129                 return "LCP";
 130         case PID_IPCP:
 131                 return "IPCP";
 132         case PID_IPV6CP:
 133                 return "IPV6CP";
 134         default:
 135                 return NULL;
 136         }
 137 }
 138
 139 static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
 140 {
 141         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 142
 143         if (skb->len < sizeof(struct hdlc_header))
 144                 return htons(ETH_P_HDLC);
 145         if (data->address != HDLC_ADDR_ALLSTATIONS ||
 146             data->control != HDLC_CTRL_UI)
 147                 return htons(ETH_P_HDLC);
 148
 149         switch (data->protocol) {
 150         case cpu_to_be16(PID_IP):
 151                 skb_pull(skb, sizeof(struct hdlc_header));
 152                 return htons(ETH_P_IP);
 153
 154         case cpu_to_be16(PID_IPV6):
 155                 skb_pull(skb, sizeof(struct hdlc_header));
 156                 return htons(ETH_P_IPV6);
 157
 158         default:
 159                 return htons(ETH_P_HDLC);
 160         }
 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
 197 static void ppp_tx_flush(void)
 198 {
 199         struct sk_buff *skb;
 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                 netdev_warn(dev, "out of memory in ppp_tx_cp()\n");
 224                 return;
 225         }
 226         skb_reserve(skb, sizeof(struct hdlc_header));
 227
 228         cp = skb_put(skb, sizeof(struct cp_header));
 229         cp->code = code;
 230         cp->id = id;
 231         cp->len = htons(sizeof(struct cp_header) + magic_len + len);
 232
 233         if (magic_len)
 234                 skb_put_data(skb, &magic, magic_len);
 235         if (len)
 236                 skb_put_data(skb, data, len);
 237
 238 #if DEBUG_CP
 239         BUG_ON(code >= CP_CODES);
 240         ptr = debug_buffer;
 241         *ptr = '\x0';
 242         for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
 243                 sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
 244                 ptr += strlen(ptr);
 245         }
 246         printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
 247                proto_name(pid), code_names[code], id, debug_buffer);
 248 #endif
 249
 250         ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
 251
 252         skb->priority = TC_PRIO_CONTROL;
 253         skb->dev = dev;
 254         skb->protocol = htons(ETH_P_HDLC);
 255         skb_reset_network_header(skb);
 256         skb_queue_tail(&tx_queue, skb);
 257 }
 258
 259
 260 /* State transition table (compare STD-51)
 261    Events                                   Actions
 262    TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
 263    TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
 264
 265    RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
 266    RCR- = Receive-Configure-Request (Bad)
 267    RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
 268    RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
 269
 270    RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
 271    RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
 272
 273    RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
 274    RXJ+ = Receive-Code-Reject (permitted)
 275        or Receive-Protocol-Reject
 276    RXJ- = Receive-Code-Reject (catastrophic)
 277        or Receive-Protocol-Reject
 278 */
 279 static int cp_table[EVENTS][STATES] = {
 280         /* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
 281              0           1         2       3       4      5          6    */
 282         {IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
 283         {   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
 284         {   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
 285         {   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
 286         {  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
 287         {  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
 288         {  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
 289         {  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
 290         {  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
 291         {    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
 292         {  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
 293         {    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
 294         {    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
 295 };
 296
 297
 298 /* SCA: RCR+ must supply id, len and data
 299    SCN: RCR- must supply code, id, len and data
 300    STA: RTR must supply id
 301    SCJ: RUC must supply CP packet len and data */
 302 static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
 303                          u8 id, unsigned int len, const void *data)
 304 {
 305         int old_state, action;
 306         struct ppp *ppp = get_ppp(dev);
 307         struct proto *proto = get_proto(dev, pid);
 308
 309         old_state = proto->state;
 310         BUG_ON(old_state >= STATES);
 311         BUG_ON(event >= EVENTS);
 312
 313 #if DEBUG_STATE
 314         printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
 315                proto_name(pid), event_names[event], state_names[proto->state]);
 316 #endif
 317
 318         action = cp_table[event][old_state];
 319
 320         proto->state = action & STATE_MASK;
 321         if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
 322                 mod_timer(&proto->timer, proto->timeout =
 323                           jiffies + ppp->req_timeout * HZ);
 324         if (action & ZRC)
 325                 proto->restart_counter = 0;
 326         if (action & IRC)
 327                 proto->restart_counter = (proto->state == STOPPING) ?
 328                         ppp->term_retries : ppp->cr_retries;
 329
 330         if (action & SCR)       /* send Configure-Request */
 331                 ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
 332                           0, NULL);
 333         if (action & SCA)       /* send Configure-Ack */
 334                 ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
 335         if (action & SCN)       /* send Configure-Nak/Reject */
 336                 ppp_tx_cp(dev, pid, code, id, len, data);
 337         if (action & STR)       /* send Terminate-Request */
 338                 ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
 339         if (action & STA)       /* send Terminate-Ack */
 340                 ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
 341         if (action & SCJ)       /* send Code-Reject */
 342                 ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
 343
 344         if (old_state != OPENED && proto->state == OPENED) {
 345                 netdev_info(dev, "%s up\n", proto_name(pid));
 346                 if (pid == PID_LCP) {
 347                         netif_dormant_off(dev);
 348                         ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
 349                         ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
 350                         ppp->last_pong = jiffies;
 351                         mod_timer(&proto->timer, proto->timeout =
 352                                   jiffies + ppp->keepalive_interval * HZ);
 353                 }
 354         }
 355         if (old_state == OPENED && proto->state != OPENED) {
 356                 netdev_info(dev, "%s down\n", proto_name(pid));
 357                 if (pid == PID_LCP) {
 358                         netif_dormant_on(dev);
 359                         ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
 360                         ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
 361                 }
 362         }
 363         if (old_state != CLOSED && proto->state == CLOSED)
 364                 del_timer(&proto->timer);
 365
 366 #if DEBUG_STATE
 367         printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
 368                proto_name(pid), event_names[event], state_names[proto->state]);
 369 #endif
 370 }
 371
 372
 373 static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
 374                             unsigned int req_len, const u8 *data)
 375 {
 376         static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
 377         const u8 *opt;
 378         u8 *out;
 379         unsigned int len = req_len, nak_len = 0, rej_len = 0;
 380
 381         if (!(out = kmalloc(len, GFP_ATOMIC))) {
 382                 dev->stats.rx_dropped++;
 383                 return; /* out of memory, ignore CR packet */
 384         }
 385
 386         for (opt = data; len; len -= opt[1], opt += opt[1]) {
 387                 if (len < 2 || opt[1] < 2 || len < opt[1])
 388                         goto err_out;
 389
 390                 if (pid == PID_LCP)
 391                         switch (opt[0]) {
 392                         case LCP_OPTION_MRU:
 393                                 continue; /* MRU always OK and > 1500 bytes? */
 394
 395                         case LCP_OPTION_ACCM: /* async control character map */
 396                                 if (opt[1] < sizeof(valid_accm))
 397                                         goto err_out;
 398                                 if (!memcmp(opt, valid_accm,
 399                                             sizeof(valid_accm)))
 400                                         continue;
 401                                 if (!rej_len) { /* NAK it */
 402                                         memcpy(out + nak_len, valid_accm,
 403                                                sizeof(valid_accm));
 404                                         nak_len += sizeof(valid_accm);
 405                                         continue;
 406                                 }
 407                                 break;
 408                         case LCP_OPTION_MAGIC:
 409                                 if (len < 6)
 410                                         goto err_out;
 411                                 if (opt[1] != 6 || (!opt[2] && !opt[3] &&
 412                                                     !opt[4] && !opt[5]))
 413                                         break; /* reject invalid magic number */
 414                                 continue;
 415                         }
 416                 /* reject this option */
 417                 memcpy(out + rej_len, opt, opt[1]);
 418                 rej_len += opt[1];
 419         }
 420
 421         if (rej_len)
 422                 ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
 423         else if (nak_len)
 424                 ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
 425         else
 426                 ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
 427
 428         kfree(out);
 429         return;
 430
 431 err_out:
 432         dev->stats.rx_errors++;
 433         kfree(out);
 434 }
 435
 436 static int ppp_rx(struct sk_buff *skb)
 437 {
 438         struct hdlc_header *hdr = (struct hdlc_header*)skb->data;
 439         struct net_device *dev = skb->dev;
 440         struct ppp *ppp = get_ppp(dev);
 441         struct proto *proto;
 442         struct cp_header *cp;
 443         unsigned long flags;
 444         unsigned int len;
 445         u16 pid;
 446 #if DEBUG_CP
 447         int i;
 448         char *ptr;
 449 #endif
 450
 451         spin_lock_irqsave(&ppp->lock, flags);
 452         /* Check HDLC header */
 453         if (skb->len < sizeof(struct hdlc_header))
 454                 goto rx_error;
 455         cp = skb_pull(skb, sizeof(struct hdlc_header));
 456         if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
 457             hdr->control != HDLC_CTRL_UI)
 458                 goto rx_error;
 459
 460         pid = ntohs(hdr->protocol);
 461         proto = get_proto(dev, pid);
 462         if (!proto) {
 463                 if (ppp->protos[IDX_LCP].state == OPENED)
 464                         ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
 465                                   ++ppp->seq, skb->len + 2, &hdr->protocol);
 466                 goto rx_error;
 467         }
 468
 469         len = ntohs(cp->len);
 470         if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
 471             skb->len < len /* truncated packet? */)
 472                 goto rx_error;
 473         skb_pull(skb, sizeof(struct cp_header));
 474         len -= sizeof(struct cp_header);
 475
 476         /* HDLC and CP headers stripped from skb */
 477 #if DEBUG_CP
 478         if (cp->code < CP_CODES)
 479                 sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
 480                         cp->id);
 481         else
 482                 sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
 483         ptr = debug_buffer + strlen(debug_buffer);
 484         for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
 485                 sprintf(ptr, " %02X", skb->data[i]);
 486                 ptr += strlen(ptr);
 487         }
 488         printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
 489                debug_buffer);
 490 #endif
 491
 492         /* LCP only */
 493         if (pid == PID_LCP)
 494                 switch (cp->code) {
 495                 case LCP_PROTO_REJ:
 496                         pid = ntohs(*(__be16*)skb->data);
 497                         if (pid == PID_LCP || pid == PID_IPCP ||
 498                             pid == PID_IPV6CP)
 499                                 ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
 500                                              0, NULL);
 501                         goto out;
 502
 503                 case LCP_ECHO_REQ: /* send Echo-Reply */
 504                         if (len >= 4 && proto->state == OPENED)
 505                                 ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
 506                                           cp->id, len - 4, skb->data + 4);
 507                         goto out;
 508
 509                 case LCP_ECHO_REPLY:
 510                         if (cp->id == ppp->echo_id)
 511                                 ppp->last_pong = jiffies;
 512                         goto out;
 513
 514                 case LCP_DISC_REQ: /* discard */
 515                         goto out;
 516                 }
 517
 518         /* LCP, IPCP and IPV6CP */
 519         switch (cp->code) {
 520         case CP_CONF_REQ:
 521                 ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
 522                 break;
 523
 524         case CP_CONF_ACK:
 525                 if (cp->id == proto->cr_id)
 526                         ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
 527                 break;
 528
 529         case CP_CONF_REJ:
 530         case CP_CONF_NAK:
 531                 if (cp->id == proto->cr_id)
 532                         ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
 533                 break;
 534
 535         case CP_TERM_REQ:
 536                 ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
 537                 break;
 538
 539         case CP_TERM_ACK:
 540                 ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
 541                 break;
 542
 543         case CP_CODE_REJ:
 544                 ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
 545                 break;
 546
 547         default:
 548                 len += sizeof(struct cp_header);
 549                 if (len > dev->mtu)
 550                         len = dev->mtu;
 551                 ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
 552                 break;
 553         }
 554         goto out;
 555
 556 rx_error:
 557         dev->stats.rx_errors++;
 558 out:
 559         spin_unlock_irqrestore(&ppp->lock, flags);
 560         dev_kfree_skb_any(skb);
 561         ppp_tx_flush();
 562         return NET_RX_DROP;
 563 }
 564
 565 static void ppp_timer(struct timer_list *t)
 566 {
 567         struct proto *proto = from_timer(proto, t, timer);
 568         struct ppp *ppp = get_ppp(proto->dev);
 569         unsigned long flags;
 570
 571         spin_lock_irqsave(&ppp->lock, flags);
 572         /* mod_timer could be called after we entered this function but
 573          * before we got the lock.
 574          */
 575         if (timer_pending(&proto->timer)) {
 576                 spin_unlock_irqrestore(&ppp->lock, flags);
 577                 return;
 578         }
 579         switch (proto->state) {
 580         case STOPPING:
 581         case REQ_SENT:
 582         case ACK_RECV:
 583         case ACK_SENT:
 584                 if (proto->restart_counter) {
 585                         ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 586                                      0, NULL);
 587                         proto->restart_counter--;
 588                 } else if (netif_carrier_ok(proto->dev))
 589                         ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 590                                      0, NULL);
 591                 else
 592                         ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
 593                                      0, NULL);
 594                 break;
 595
 596         case OPENED:
 597                 if (proto->pid != PID_LCP)
 598                         break;
 599                 if (time_after(jiffies, ppp->last_pong +
 600                                ppp->keepalive_timeout * HZ)) {
 601                         netdev_info(proto->dev, "Link down\n");
 602                         ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
 603                         ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
 604                 } else {        /* send keep-alive packet */
 605                         ppp->echo_id = ++ppp->seq;
 606                         ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
 607                                   ppp->echo_id, 0, NULL);
 608                         proto->timer.expires = jiffies +
 609                                 ppp->keepalive_interval * HZ;
 610                         add_timer(&proto->timer);
 611                 }
 612                 break;
 613         }
 614         spin_unlock_irqrestore(&ppp->lock, flags);
 615         ppp_tx_flush();
 616 }
 617
 618
 619 static void ppp_start(struct net_device *dev)
 620 {
 621         struct ppp *ppp = get_ppp(dev);
 622         int i;
 623
 624         for (i = 0; i < IDX_COUNT; i++) {
 625                 struct proto *proto = &ppp->protos[i];
 626                 proto->dev = dev;
 627                 timer_setup(&proto->timer, ppp_timer, 0);
 628                 proto->state = CLOSED;
 629         }
 630         ppp->protos[IDX_LCP].pid = PID_LCP;
 631         ppp->protos[IDX_IPCP].pid = PID_IPCP;
 632         ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
 633
 634         ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
 635 }
 636
 637 static void ppp_stop(struct net_device *dev)
 638 {
 639         ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
 640 }
 641
 642 static void ppp_close(struct net_device *dev)
 643 {
 644         ppp_tx_flush();
 645 }
 646
 647 static struct hdlc_proto proto = {
 648         .start          = ppp_start,
 649         .stop           = ppp_stop,
 650         .close          = ppp_close,
 651         .type_trans     = ppp_type_trans,
 652         .ioctl          = ppp_ioctl,
 653         .netif_rx       = ppp_rx,
 654         .module         = THIS_MODULE,
 655 };
 656
 657 static const struct header_ops ppp_header_ops = {
 658         .create = ppp_hard_header,
 659 };
 660
 661 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr)
 662 {
 663         hdlc_device *hdlc = dev_to_hdlc(dev);
 664         struct ppp *ppp;
 665         int result;
 666
 667         switch (ifr->ifr_settings.type) {
 668         case IF_GET_PROTO:
 669                 if (dev_to_hdlc(dev)->proto != &proto)
 670                         return -EINVAL;
 671                 ifr->ifr_settings.type = IF_PROTO_PPP;
 672                 return 0; /* return protocol only, no settable parameters */
 673
 674         case IF_PROTO_PPP:
 675                 if (!capable(CAP_NET_ADMIN))
 676                         return -EPERM;
 677
 678                 if (dev->flags & IFF_UP)
 679                         return -EBUSY;
 680
 681                 /* no settable parameters */
 682
 683                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 684                 if (result)
 685                         return result;
 686
 687                 result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
 688                 if (result)
 689                         return result;
 690
 691                 ppp = get_ppp(dev);
 692                 spin_lock_init(&ppp->lock);
 693                 ppp->req_timeout = 2;
 694                 ppp->cr_retries = 10;
 695                 ppp->term_retries = 2;
 696                 ppp->keepalive_interval = 10;
 697                 ppp->keepalive_timeout = 60;
 698
 699                 dev->hard_header_len = sizeof(struct hdlc_header);
 700                 dev->header_ops = &ppp_header_ops;
 701                 dev->type = ARPHRD_PPP;
 702                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 703                 netif_dormant_on(dev);
 704                 return 0;
 705         }
 706
 707         return -EINVAL;
 708 }
 709
 710
 711 static int __init mod_init(void)
 712 {
 713         skb_queue_head_init(&tx_queue);
 714         register_hdlc_protocol(&proto);
 715         return 0;
 716 }
 717
 718 static void __exit mod_exit(void)
 719 {
 720         unregister_hdlc_protocol(&proto);
 721 }
 722
 723
 724 module_init(mod_init);
 725 module_exit(mod_exit);
 726
 727 MODULE_AUTHOR("Krzysztof Halasa <[email protected]>");
 728 MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
 729 MODULE_LICENSE("GPL v2");