drivers/net/wan/syncppp.c

   1 /*
   2  *      NET3:   A (fairly minimal) implementation of synchronous PPP for Linux
   3  *              as well as a CISCO HDLC implementation. See the copyright
   4  *              message below for the original source.
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the license, or (at your option) any later version.
  10  *
  11  *      Note however. This code is also used in a different form by FreeBSD.
  12  *      Therefore when making any non OS specific change please consider
  13  *      contributing it back to the original author under the terms
  14  *      below in addition.
  15  *              -- Alan
  16  *
  17  *      Port for Linux-2.1 by Jan "Yenya" Kasprzak <kas@fi.muni.cz>
  18  */
  19
  20 /*
  21  * Synchronous PPP/Cisco link level subroutines.
  22  * Keepalive protocol implemented in both Cisco and PPP modes.
  23  *
  24  * Copyright (C) 1994 Cronyx Ltd.
  25  * Author: Serge Vakulenko, <vak@zebub.msk.su>
  26  *
  27  * This software is distributed with NO WARRANTIES, not even the implied
  28  * warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  29  *
  30  * Authors grant any other persons or organisations permission to use
  31  * or modify this software as long as this message is kept with the software,
  32  * all derivative works or modified versions.
  33  *
  34  * Version 1.9, Wed Oct  4 18:58:15 MSK 1995
  35  *
  36  * $Id: syncppp.c,v 1.18 2000/04/11 05:25:31 asj Exp $
  37  */
  38 #undef DEBUG
  39
  40 #include <linux/config.h>
  41 #include <linux/module.h>
  42 #include <linux/kernel.h>
  43 #include <linux/errno.h>
  44 #include <linux/init.h>
  45 #include <linux/if_arp.h>
  46 #include <linux/skbuff.h>
  47 #include <linux/route.h>
  48 #include <linux/netdevice.h>
  49 #include <linux/inetdevice.h>
  50 #include <linux/random.h>
  51 #include <linux/pkt_sched.h>
  52 #include <linux/spinlock.h>
  53 #include <linux/rcupdate.h>
  54
  55 #include <net/syncppp.h>
  56
  57 #include <asm/byteorder.h>
  58 #include <asm/uaccess.h>
  59
  60 #define MAXALIVECNT     6               /* max. alive packets */
  61
  62 #define PPP_ALLSTATIONS 0xff            /* All-Stations broadcast address */
  63 #define PPP_UI          0x03            /* Unnumbered Information */
  64 #define PPP_IP          0x0021          /* Internet Protocol */
  65 #define PPP_ISO         0x0023          /* ISO OSI Protocol */
  66 #define PPP_XNS         0x0025          /* Xerox NS Protocol */
  67 #define PPP_IPX         0x002b          /* Novell IPX Protocol */
  68 #define PPP_LCP         0xc021          /* Link Control Protocol */
  69 #define PPP_IPCP        0x8021          /* Internet Protocol Control Protocol */
  70
  71 #define LCP_CONF_REQ    1               /* PPP LCP configure request */
  72 #define LCP_CONF_ACK    2               /* PPP LCP configure acknowledge */
  73 #define LCP_CONF_NAK    3               /* PPP LCP configure negative ack */
  74 #define LCP_CONF_REJ    4               /* PPP LCP configure reject */
  75 #define LCP_TERM_REQ    5               /* PPP LCP terminate request */
  76 #define LCP_TERM_ACK    6               /* PPP LCP terminate acknowledge */
  77 #define LCP_CODE_REJ    7               /* PPP LCP code reject */
  78 #define LCP_PROTO_REJ   8               /* PPP LCP protocol reject */
  79 #define LCP_ECHO_REQ    9               /* PPP LCP echo request */
  80 #define LCP_ECHO_REPLY  10              /* PPP LCP echo reply */
  81 #define LCP_DISC_REQ    11              /* PPP LCP discard request */
  82
  83 #define LCP_OPT_MRU             1       /* maximum receive unit */
  84 #define LCP_OPT_ASYNC_MAP       2       /* async control character map */
  85 #define LCP_OPT_AUTH_PROTO      3       /* authentication protocol */
  86 #define LCP_OPT_QUAL_PROTO      4       /* quality protocol */
  87 #define LCP_OPT_MAGIC           5       /* magic number */
  88 #define LCP_OPT_RESERVED        6       /* reserved */
  89 #define LCP_OPT_PROTO_COMP      7       /* protocol field compression */
  90 #define LCP_OPT_ADDR_COMP       8       /* address/control field compression */
  91
  92 #define IPCP_CONF_REQ   LCP_CONF_REQ    /* PPP IPCP configure request */
  93 #define IPCP_CONF_ACK   LCP_CONF_ACK    /* PPP IPCP configure acknowledge */
  94 #define IPCP_CONF_NAK   LCP_CONF_NAK    /* PPP IPCP configure negative ack */
  95 #define IPCP_CONF_REJ   LCP_CONF_REJ    /* PPP IPCP configure reject */
  96 #define IPCP_TERM_REQ   LCP_TERM_REQ    /* PPP IPCP terminate request */
  97 #define IPCP_TERM_ACK   LCP_TERM_ACK    /* PPP IPCP terminate acknowledge */
  98 #define IPCP_CODE_REJ   LCP_CODE_REJ    /* PPP IPCP code reject */
  99
 100 #define CISCO_MULTICAST         0x8f    /* Cisco multicast address */
 101 #define CISCO_UNICAST           0x0f    /* Cisco unicast address */
 102 #define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
 103 #define CISCO_ADDR_REQ          0       /* Cisco address request */
 104 #define CISCO_ADDR_REPLY        1       /* Cisco address reply */
 105 #define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */
 106
 107 struct ppp_header {
 108         u8 address;
 109         u8 control;
 110         u16 protocol;
 111 };
 112 #define PPP_HEADER_LEN          sizeof (struct ppp_header)
 113
 114 struct lcp_header {
 115         u8 type;
 116         u8 ident;
 117         u16 len;
 118 };
 119 #define LCP_HEADER_LEN          sizeof (struct lcp_header)
 120
 121 struct cisco_packet {
 122         u32 type;
 123         u32 par1;
 124         u32 par2;
 125         u16 rel;
 126         u16 time0;
 127         u16 time1;
 128 };
 129 #define CISCO_PACKET_LEN 18
 130 #define CISCO_BIG_PACKET_LEN 20
 131
 132 static struct sppp *spppq;
 133 static struct timer_list sppp_keepalive_timer;
 134 static DEFINE_SPINLOCK(spppq_lock);
 135
 136 /* global xmit queue for sending packets while spinlock is held */
 137 static struct sk_buff_head tx_queue;
 138
 139 static void sppp_keepalive (unsigned long dummy);
 140 static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
 141         u8 ident, u16 len, void *data);
 142 static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2);
 143 static void sppp_lcp_input (struct sppp *sp, struct sk_buff *m);
 144 static void sppp_cisco_input (struct sppp *sp, struct sk_buff *m);
 145 static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *m);
 146 static void sppp_lcp_open (struct sppp *sp);
 147 static void sppp_ipcp_open (struct sppp *sp);
 148 static int sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
 149         int len, u32 *magic);
 150 static void sppp_cp_timeout (unsigned long arg);
 151 static char *sppp_lcp_type_name (u8 type);
 152 static char *sppp_ipcp_type_name (u8 type);
 153 static void sppp_print_bytes (u8 *p, u16 len);
 154
 155 static int debug;
 156
 157 /* Flush global outgoing packet queue to dev_queue_xmit().
 158  *
 159  * dev_queue_xmit() must be called with interrupts enabled
 160  * which means it can't be called with spinlocks held.
 161  * If a packet needs to be sent while a spinlock is held,
 162  * then put the packet into tx_queue, and call sppp_flush_xmit()
 163  * after spinlock is released.
 164  */
 165 static void sppp_flush_xmit(void)
 166 {
 167         struct sk_buff *skb;
 168         while ((skb = skb_dequeue(&tx_queue)) != NULL)
 169                 dev_queue_xmit(skb);
 170 }
 171
 172 /*
 173  *      Interface down stub
 174  */
 175
 176 static void if_down(struct net_device *dev)
 177 {
 178         struct sppp *sp = (struct sppp *)sppp_of(dev);
 179
 180         sp->pp_link_state=SPPP_LINK_DOWN;
 181 }
 182
 183 /*
 184  * Timeout routine activations.
 185  */
 186
 187 static void sppp_set_timeout(struct sppp *p,int s)
 188 {
 189         if (! (p->pp_flags & PP_TIMO))
 190         {
 191                 init_timer(&p->pp_timer);
 192                 p->pp_timer.function=sppp_cp_timeout;
 193                 p->pp_timer.expires=jiffies+s*HZ;
 194                 p->pp_timer.data=(unsigned long)p;
 195                 p->pp_flags |= PP_TIMO;
 196                 add_timer(&p->pp_timer);
 197         }
 198 }
 199
 200 static void sppp_clear_timeout(struct sppp *p)
 201 {
 202         if (p->pp_flags & PP_TIMO)
 203         {
 204                 del_timer(&p->pp_timer);
 205                 p->pp_flags &= ~PP_TIMO;
 206         }
 207 }
 208
 209 /**
 210  *      sppp_input -    receive and process a WAN PPP frame
 211  *      @skb:   The buffer to process
 212  *      @dev:   The device it arrived on
 213  *
 214  *      This can be called directly by cards that do not have
 215  *      timing constraints but is normally called from the network layer
 216  *      after interrupt servicing to process frames queued via netif_rx().
 217  *
 218  *      We process the options in the card. If the frame is destined for
 219  *      the protocol stacks then it requeues the frame for the upper level
 220  *      protocol. If it is a control from it is processed and discarded
 221  *      here.
 222  */
 223
 224 void sppp_input (struct net_device *dev, struct sk_buff *skb)
 225 {
 226         struct ppp_header *h;
 227         struct sppp *sp = (struct sppp *)sppp_of(dev);
 228         unsigned long flags;
 229
 230         skb->dev=dev;
 231         skb->mac.raw=skb->data;
 232
 233         if (dev->flags & IFF_RUNNING)
 234         {
 235                 /* Count received bytes, add FCS and one flag */
 236                 sp->ibytes+= skb->len + 3;
 237                 sp->ipkts++;
 238         }
 239
 240         if (!pskb_may_pull(skb, PPP_HEADER_LEN)) {
 241                 /* Too small packet, drop it. */
 242                 if (sp->pp_flags & PP_DEBUG)
 243                         printk (KERN_DEBUG "%s: input packet is too small, %d bytes\n",
 244                                 dev->name, skb->len);
 245                 kfree_skb(skb);
 246                 return;
 247         }
 248
 249         /* Get PPP header. */
 250         h = (struct ppp_header *)skb->data;
 251         skb_pull(skb,sizeof(struct ppp_header));
 252
 253         spin_lock_irqsave(&sp->lock, flags);
 254
 255         switch (h->address) {
 256         default:        /* Invalid PPP packet. */
 257                 goto invalid;
 258         case PPP_ALLSTATIONS:
 259                 if (h->control != PPP_UI)
 260                         goto invalid;
 261                 if (sp->pp_flags & PP_CISCO) {
 262                         if (sp->pp_flags & PP_DEBUG)
 263                                 printk (KERN_WARNING "%s: PPP packet in Cisco mode <0x%x 0x%x 0x%x>\n",
 264                                         dev->name,
 265                                         h->address, h->control, ntohs (h->protocol));
 266                         goto drop;
 267                 }
 268                 switch (ntohs (h->protocol)) {
 269                 default:
 270                         if (sp->lcp.state == LCP_STATE_OPENED)
 271                                 sppp_cp_send (sp, PPP_LCP, LCP_PROTO_REJ,
 272                                         ++sp->pp_seq, skb->len + 2,
 273                                         &h->protocol);
 274                         if (sp->pp_flags & PP_DEBUG)
 275                                 printk (KERN_WARNING "%s: invalid input protocol <0x%x 0x%x 0x%x>\n",
 276                                         dev->name,
 277                                         h->address, h->control, ntohs (h->protocol));
 278                         goto drop;
 279                 case PPP_LCP:
 280                         sppp_lcp_input (sp, skb);
 281                         goto drop;
 282                 case PPP_IPCP:
 283                         if (sp->lcp.state == LCP_STATE_OPENED)
 284                                 sppp_ipcp_input (sp, skb);
 285                         else
 286                                 printk(KERN_DEBUG "IPCP when still waiting LCP finish.\n");
 287                         goto drop;
 288                 case PPP_IP:
 289                         if (sp->ipcp.state == IPCP_STATE_OPENED) {
 290                                 if(sp->pp_flags&PP_DEBUG)
 291                                         printk(KERN_DEBUG "Yow an IP frame.\n");
 292                                 skb->protocol=htons(ETH_P_IP);
 293                                 netif_rx(skb);
 294                                 dev->last_rx = jiffies;
 295                                 goto done;
 296                         }
 297                         break;
 298 #ifdef IPX
 299                 case PPP_IPX:
 300                         /* IPX IPXCP not implemented yet */
 301                         if (sp->lcp.state == LCP_STATE_OPENED) {
 302                                 skb->protocol=htons(ETH_P_IPX);
 303                                 netif_rx(skb);
 304                                 dev->last_rx = jiffies;
 305                                 goto done;
 306                         }
 307                         break;
 308 #endif
 309                 }
 310                 break;
 311         case CISCO_MULTICAST:
 312         case CISCO_UNICAST:
 313                 /* Don't check the control field here (RFC 1547). */
 314                 if (! (sp->pp_flags & PP_CISCO)) {
 315                         if (sp->pp_flags & PP_DEBUG)
 316                                 printk (KERN_WARNING "%s: Cisco packet in PPP mode <0x%x 0x%x 0x%x>\n",
 317                                         dev->name,
 318                                         h->address, h->control, ntohs (h->protocol));
 319                         goto drop;
 320                 }
 321                 switch (ntohs (h->protocol)) {
 322                 default:
 323                         goto invalid;
 324                 case CISCO_KEEPALIVE:
 325                         sppp_cisco_input (sp, skb);
 326                         goto drop;
 327 #ifdef CONFIG_INET
 328                 case ETH_P_IP:
 329                         skb->protocol=htons(ETH_P_IP);
 330                         netif_rx(skb);
 331                         dev->last_rx = jiffies;
 332                         goto done;
 333 #endif
 334 #ifdef CONFIG_IPX
 335                 case ETH_P_IPX:
 336                         skb->protocol=htons(ETH_P_IPX);
 337                         netif_rx(skb);
 338                         dev->last_rx = jiffies;
 339                         goto done;
 340 #endif
 341                 }
 342                 break;
 343         }
 344         goto drop;
 345
 346 invalid:
 347         if (sp->pp_flags & PP_DEBUG)
 348                 printk (KERN_WARNING "%s: invalid input packet <0x%x 0x%x 0x%x>\n",
 349                         dev->name, h->address, h->control, ntohs (h->protocol));
 350 drop:
 351         kfree_skb(skb);
 352 done:
 353         spin_unlock_irqrestore(&sp->lock, flags);
 354         sppp_flush_xmit();
 355         return;
 356 }
 357
 358 EXPORT_SYMBOL(sppp_input);
 359
 360 /*
 361  *      Handle transmit packets.
 362  */
 363
 364 static int sppp_hard_header(struct sk_buff *skb, struct net_device *dev, __u16 type,
 365                 void *daddr, void *saddr, unsigned int len)
 366 {
 367         struct sppp *sp = (struct sppp *)sppp_of(dev);
 368         struct ppp_header *h;
 369         skb_push(skb,sizeof(struct ppp_header));
 370         h=(struct ppp_header *)skb->data;
 371         if(sp->pp_flags&PP_CISCO)
 372         {
 373                 h->address = CISCO_UNICAST;
 374                 h->control = 0;
 375         }
 376         else
 377         {
 378                 h->address = PPP_ALLSTATIONS;
 379                 h->control = PPP_UI;
 380         }
 381         if(sp->pp_flags & PP_CISCO)
 382         {
 383                 h->protocol = htons(type);
 384         }
 385         else switch(type)
 386         {
 387                 case ETH_P_IP:
 388                         h->protocol = htons(PPP_IP);
 389                         break;
 390                 case ETH_P_IPX:
 391                         h->protocol = htons(PPP_IPX);
 392                         break;
 393         }
 394         return sizeof(struct ppp_header);
 395 }
 396
 397 static int sppp_rebuild_header(struct sk_buff *skb)
 398 {
 399         return 0;
 400 }
 401
 402 /*
 403  * Send keepalive packets, every 10 seconds.
 404  */
 405
 406 static void sppp_keepalive (unsigned long dummy)
 407 {
 408         struct sppp *sp;
 409         unsigned long flags;
 410
 411         spin_lock_irqsave(&spppq_lock, flags);
 412
 413         for (sp=spppq; sp; sp=sp->pp_next)
 414         {
 415                 struct net_device *dev = sp->pp_if;
 416
 417                 /* Keepalive mode disabled or channel down? */
 418                 if (! (sp->pp_flags & PP_KEEPALIVE) ||
 419                     ! (dev->flags & IFF_UP))
 420                         continue;
 421
 422                 spin_lock(&sp->lock);
 423
 424                 /* No keepalive in PPP mode if LCP not opened yet. */
 425                 if (! (sp->pp_flags & PP_CISCO) &&
 426                     sp->lcp.state != LCP_STATE_OPENED) {
 427                         spin_unlock(&sp->lock);
 428                         continue;
 429                 }
 430
 431                 if (sp->pp_alivecnt == MAXALIVECNT) {
 432                         /* No keepalive packets got.  Stop the interface. */
 433                         printk (KERN_WARNING "%s: protocol down\n", dev->name);
 434                         if_down (dev);
 435                         if (! (sp->pp_flags & PP_CISCO)) {
 436                                 /* Shut down the PPP link. */
 437                                 sp->lcp.magic = jiffies;
 438                                 sp->lcp.state = LCP_STATE_CLOSED;
 439                                 sp->ipcp.state = IPCP_STATE_CLOSED;
 440                                 sppp_clear_timeout (sp);
 441                                 /* Initiate negotiation. */
 442                                 sppp_lcp_open (sp);
 443                         }
 444                 }
 445                 if (sp->pp_alivecnt <= MAXALIVECNT)
 446                         ++sp->pp_alivecnt;
 447                 if (sp->pp_flags & PP_CISCO)
 448                         sppp_cisco_send (sp, CISCO_KEEPALIVE_REQ, ++sp->pp_seq,
 449                                 sp->pp_rseq);
 450                 else if (sp->lcp.state == LCP_STATE_OPENED) {
 451                         long nmagic = htonl (sp->lcp.magic);
 452                         sp->lcp.echoid = ++sp->pp_seq;
 453                         sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REQ,
 454                                 sp->lcp.echoid, 4, &nmagic);
 455                 }
 456
 457                 spin_unlock(&sp->lock);
 458         }
 459         spin_unlock_irqrestore(&spppq_lock, flags);
 460         sppp_flush_xmit();
 461         sppp_keepalive_timer.expires=jiffies+10*HZ;
 462         add_timer(&sppp_keepalive_timer);
 463 }
 464
 465 /*
 466  * Handle incoming PPP Link Control Protocol packets.
 467  */
 468
 469 static void sppp_lcp_input (struct sppp *sp, struct sk_buff *skb)
 470 {
 471         struct lcp_header *h;
 472         struct net_device *dev = sp->pp_if;
 473         int len = skb->len;
 474         u8 *p, opt[6];
 475         u32 rmagic;
 476
 477         if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
 478                 if (sp->pp_flags & PP_DEBUG)
 479                         printk (KERN_WARNING "%s: invalid lcp packet length: %d bytes\n",
 480                                 dev->name, len);
 481                 return;
 482         }
 483         h = (struct lcp_header *)skb->data;
 484         skb_pull(skb,sizeof(struct lcp_header *));
 485
 486         if (sp->pp_flags & PP_DEBUG)
 487         {
 488                 char state = '?';
 489                 switch (sp->lcp.state) {
 490                 case LCP_STATE_CLOSED:   state = 'C'; break;
 491                 case LCP_STATE_ACK_RCVD: state = 'R'; break;
 492                 case LCP_STATE_ACK_SENT: state = 'S'; break;
 493                 case LCP_STATE_OPENED:   state = 'O'; break;
 494                 }
 495                 printk (KERN_WARNING "%s: lcp input(%c): %d bytes <%s id=%xh len=%xh",
 496                         dev->name, state, len,
 497                         sppp_lcp_type_name (h->type), h->ident, ntohs (h->len));
 498                 if (len > 4)
 499                         sppp_print_bytes ((u8*) (h+1), len-4);
 500                 printk (">\n");
 501         }
 502         if (len > ntohs (h->len))
 503                 len = ntohs (h->len);
 504         switch (h->type) {
 505         default:
 506                 /* Unknown packet type -- send Code-Reject packet. */
 507                 sppp_cp_send (sp, PPP_LCP, LCP_CODE_REJ, ++sp->pp_seq,
 508                         skb->len, h);
 509                 break;
 510         case LCP_CONF_REQ:
 511                 if (len < 4) {
 512                         if (sp->pp_flags & PP_DEBUG)
 513                                 printk (KERN_DEBUG"%s: invalid lcp configure request packet length: %d bytes\n",
 514                                         dev->name, len);
 515                         break;
 516                 }
 517                 if (len>4 && !sppp_lcp_conf_parse_options (sp, h, len, &rmagic))
 518                         goto badreq;
 519                 if (rmagic == sp->lcp.magic) {
 520                         /* Local and remote magics equal -- loopback? */
 521                         if (sp->pp_loopcnt >= MAXALIVECNT*5) {
 522                                 printk (KERN_WARNING "%s: loopback\n",
 523                                         dev->name);
 524                                 sp->pp_loopcnt = 0;
 525                                 if (dev->flags & IFF_UP) {
 526                                         if_down (dev);
 527                                 }
 528                         } else if (sp->pp_flags & PP_DEBUG)
 529                                 printk (KERN_DEBUG "%s: conf req: magic glitch\n",
 530                                         dev->name);
 531                         ++sp->pp_loopcnt;
 532
 533                         /* MUST send Conf-Nack packet. */
 534                         rmagic = ~sp->lcp.magic;
 535                         opt[0] = LCP_OPT_MAGIC;
 536                         opt[1] = sizeof (opt);
 537                         opt[2] = rmagic >> 24;
 538                         opt[3] = rmagic >> 16;
 539                         opt[4] = rmagic >> 8;
 540                         opt[5] = rmagic;
 541                         sppp_cp_send (sp, PPP_LCP, LCP_CONF_NAK,
 542                                 h->ident, sizeof (opt), &opt);
 543 badreq:
 544                         switch (sp->lcp.state) {
 545                         case LCP_STATE_OPENED:
 546                                 /* Initiate renegotiation. */
 547                                 sppp_lcp_open (sp);
 548                                 /* fall through... */
 549                         case LCP_STATE_ACK_SENT:
 550                                 /* Go to closed state. */
 551                                 sp->lcp.state = LCP_STATE_CLOSED;
 552                                 sp->ipcp.state = IPCP_STATE_CLOSED;
 553                         }
 554                         break;
 555                 }
 556                 /* Send Configure-Ack packet. */
 557                 sp->pp_loopcnt = 0;
 558                 if (sp->lcp.state != LCP_STATE_OPENED) {
 559                         sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
 560                                         h->ident, len-4, h+1);
 561                 }
 562                 /* Change the state. */
 563                 switch (sp->lcp.state) {
 564                 case LCP_STATE_CLOSED:
 565                         sp->lcp.state = LCP_STATE_ACK_SENT;
 566                         break;
 567                 case LCP_STATE_ACK_RCVD:
 568                         sp->lcp.state = LCP_STATE_OPENED;
 569                         sppp_ipcp_open (sp);
 570                         break;
 571                 case LCP_STATE_OPENED:
 572                         /* Remote magic changed -- close session. */
 573                         sp->lcp.state = LCP_STATE_CLOSED;
 574                         sp->ipcp.state = IPCP_STATE_CLOSED;
 575                         /* Initiate renegotiation. */
 576                         sppp_lcp_open (sp);
 577                         /* Send ACK after our REQ in attempt to break loop */
 578                         sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
 579                                         h->ident, len-4, h+1);
 580                         sp->lcp.state = LCP_STATE_ACK_SENT;
 581                         break;
 582                 }
 583                 break;
 584         case LCP_CONF_ACK:
 585                 if (h->ident != sp->lcp.confid)
 586                         break;
 587                 sppp_clear_timeout (sp);
 588                 if ((sp->pp_link_state != SPPP_LINK_UP) &&
 589                     (dev->flags & IFF_UP)) {
 590                         /* Coming out of loopback mode. */
 591                         sp->pp_link_state=SPPP_LINK_UP;
 592                         printk (KERN_INFO "%s: protocol up\n", dev->name);
 593                 }
 594                 switch (sp->lcp.state) {
 595                 case LCP_STATE_CLOSED:
 596                         sp->lcp.state = LCP_STATE_ACK_RCVD;
 597                         sppp_set_timeout (sp, 5);
 598                         break;
 599                 case LCP_STATE_ACK_SENT:
 600                         sp->lcp.state = LCP_STATE_OPENED;
 601                         sppp_ipcp_open (sp);
 602                         break;
 603                 }
 604                 break;
 605         case LCP_CONF_NAK:
 606                 if (h->ident != sp->lcp.confid)
 607                         break;
 608                 p = (u8*) (h+1);
 609                 if (len>=10 && p[0] == LCP_OPT_MAGIC && p[1] >= 4) {
 610                         rmagic = (u32)p[2] << 24 |
 611                                 (u32)p[3] << 16 | p[4] << 8 | p[5];
 612                         if (rmagic == ~sp->lcp.magic) {
 613                                 int newmagic;
 614                                 if (sp->pp_flags & PP_DEBUG)
 615                                         printk (KERN_DEBUG "%s: conf nak: magic glitch\n",
 616                                                 dev->name);
 617                                 get_random_bytes(&newmagic, sizeof(newmagic));
 618                                 sp->lcp.magic += newmagic;
 619                         } else
 620                                 sp->lcp.magic = rmagic;
 621                         }
 622                 if (sp->lcp.state != LCP_STATE_ACK_SENT) {
 623                         /* Go to closed state. */
 624                         sp->lcp.state = LCP_STATE_CLOSED;
 625                         sp->ipcp.state = IPCP_STATE_CLOSED;
 626                 }
 627                 /* The link will be renegotiated after timeout,
 628                  * to avoid endless req-nack loop. */
 629                 sppp_clear_timeout (sp);
 630                 sppp_set_timeout (sp, 2);
 631                 break;
 632         case LCP_CONF_REJ:
 633                 if (h->ident != sp->lcp.confid)
 634                         break;
 635                 sppp_clear_timeout (sp);
 636                 /* Initiate renegotiation. */
 637                 sppp_lcp_open (sp);
 638                 if (sp->lcp.state != LCP_STATE_ACK_SENT) {
 639                         /* Go to closed state. */
 640                         sp->lcp.state = LCP_STATE_CLOSED;
 641                         sp->ipcp.state = IPCP_STATE_CLOSED;
 642                 }
 643                 break;
 644         case LCP_TERM_REQ:
 645                 sppp_clear_timeout (sp);
 646                 /* Send Terminate-Ack packet. */
 647                 sppp_cp_send (sp, PPP_LCP, LCP_TERM_ACK, h->ident, 0, NULL);
 648                 /* Go to closed state. */
 649                 sp->lcp.state = LCP_STATE_CLOSED;
 650                 sp->ipcp.state = IPCP_STATE_CLOSED;
 651                 /* Initiate renegotiation. */
 652                 sppp_lcp_open (sp);
 653                 break;
 654         case LCP_TERM_ACK:
 655         case LCP_CODE_REJ:
 656         case LCP_PROTO_REJ:
 657                 /* Ignore for now. */
 658                 break;
 659         case LCP_DISC_REQ:
 660                 /* Discard the packet. */
 661                 break;
 662         case LCP_ECHO_REQ:
 663                 if (sp->lcp.state != LCP_STATE_OPENED)
 664                         break;
 665                 if (len < 8) {
 666                         if (sp->pp_flags & PP_DEBUG)
 667                                 printk (KERN_WARNING "%s: invalid lcp echo request packet length: %d bytes\n",
 668                                         dev->name, len);
 669                         break;
 670                 }
 671                 if (ntohl (*(long*)(h+1)) == sp->lcp.magic) {
 672                         /* Line loopback mode detected. */
 673                         printk (KERN_WARNING "%s: loopback\n", dev->name);
 674                         if_down (dev);
 675
 676                         /* Shut down the PPP link. */
 677                         sp->lcp.state = LCP_STATE_CLOSED;
 678                         sp->ipcp.state = IPCP_STATE_CLOSED;
 679                         sppp_clear_timeout (sp);
 680                         /* Initiate negotiation. */
 681                         sppp_lcp_open (sp);
 682                         break;
 683                 }
 684                 *(long*)(h+1) = htonl (sp->lcp.magic);
 685                 sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REPLY, h->ident, len-4, h+1);
 686                 break;
 687         case LCP_ECHO_REPLY:
 688                 if (h->ident != sp->lcp.echoid)
 689                         break;
 690                 if (len < 8) {
 691                         if (sp->pp_flags & PP_DEBUG)
 692                                 printk (KERN_WARNING "%s: invalid lcp echo reply packet length: %d bytes\n",
 693                                         dev->name, len);
 694                         break;
 695                 }
 696                 if (ntohl (*(long*)(h+1)) != sp->lcp.magic)
 697                 sp->pp_alivecnt = 0;
 698                 break;
 699         }
 700 }
 701
 702 /*
 703  * Handle incoming Cisco keepalive protocol packets.
 704  */
 705
 706 static void sppp_cisco_input (struct sppp *sp, struct sk_buff *skb)
 707 {
 708         struct cisco_packet *h;
 709         struct net_device *dev = sp->pp_if;
 710
 711         if (!pskb_may_pull(skb, sizeof(struct cisco_packet))
 712             || (skb->len != CISCO_PACKET_LEN
 713                 && skb->len != CISCO_BIG_PACKET_LEN)) {
 714                 if (sp->pp_flags & PP_DEBUG)
 715                         printk (KERN_WARNING "%s: invalid cisco packet length: %d bytes\n",
 716                                 dev->name,  skb->len);
 717                 return;
 718         }
 719         h = (struct cisco_packet *)skb->data;
 720         skb_pull(skb, sizeof(struct cisco_packet*));
 721         if (sp->pp_flags & PP_DEBUG)
 722                 printk (KERN_WARNING "%s: cisco input: %d bytes <%xh %xh %xh %xh %xh-%xh>\n",
 723                         dev->name,  skb->len,
 724                         ntohl (h->type), h->par1, h->par2, h->rel,
 725                         h->time0, h->time1);
 726         switch (ntohl (h->type)) {
 727         default:
 728                 if (sp->pp_flags & PP_DEBUG)
 729                         printk (KERN_WARNING "%s: unknown cisco packet type: 0x%x\n",
 730                                 dev->name,  ntohl (h->type));
 731                 break;
 732         case CISCO_ADDR_REPLY:
 733                 /* Reply on address request, ignore */
 734                 break;
 735         case CISCO_KEEPALIVE_REQ:
 736                 sp->pp_alivecnt = 0;
 737                 sp->pp_rseq = ntohl (h->par1);
 738                 if (sp->pp_seq == sp->pp_rseq) {
 739                         /* Local and remote sequence numbers are equal.
 740                          * Probably, the line is in loopback mode. */
 741                         int newseq;
 742                         if (sp->pp_loopcnt >= MAXALIVECNT) {
 743                                 printk (KERN_WARNING "%s: loopback\n",
 744                                         dev->name);
 745                                 sp->pp_loopcnt = 0;
 746                                 if (dev->flags & IFF_UP) {
 747                                         if_down (dev);
 748                                 }
 749                         }
 750                         ++sp->pp_loopcnt;
 751
 752                         /* Generate new local sequence number */
 753                         get_random_bytes(&newseq, sizeof(newseq));
 754                         sp->pp_seq ^= newseq;
 755                         break;
 756                 }
 757                 sp->pp_loopcnt = 0;
 758                 if (sp->pp_link_state==SPPP_LINK_DOWN &&
 759                     (dev->flags & IFF_UP)) {
 760                         sp->pp_link_state=SPPP_LINK_UP;
 761                         printk (KERN_INFO "%s: protocol up\n", dev->name);
 762                 }
 763                 break;
 764         case CISCO_ADDR_REQ:
 765                 /* Stolen from net/ipv4/devinet.c -- SIOCGIFADDR ioctl */
 766                 {
 767                 struct in_device *in_dev;
 768                 struct in_ifaddr *ifa;
 769                 u32 addr = 0, mask = ~0; /* FIXME: is the mask correct? */
 770 #ifdef CONFIG_INET
 771                 rcu_read_lock();
 772                 if ((in_dev = __in_dev_get(dev)) != NULL)
 773                 {
 774                         for (ifa=in_dev->ifa_list; ifa != NULL;
 775                                 ifa=ifa->ifa_next) {
 776                                 if (strcmp(dev->name, ifa->ifa_label) == 0)
 777                                 {
 778                                         addr = ifa->ifa_local;
 779                                         mask = ifa->ifa_mask;
 780                                         break;
 781                                 }
 782                         }
 783                 }
 784                 rcu_read_unlock();
 785 #endif
 786                 /* I hope both addr and mask are in the net order */
 787                 sppp_cisco_send (sp, CISCO_ADDR_REPLY, addr, mask);
 788                 break;
 789                 }
 790         }
 791 }
 792
 793
 794 /*
 795  * Send PPP LCP packet.
 796  */
 797
 798 static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
 799         u8 ident, u16 len, void *data)
 800 {
 801         struct ppp_header *h;
 802         struct lcp_header *lh;
 803         struct sk_buff *skb;
 804         struct net_device *dev = sp->pp_if;
 805
 806         skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+LCP_HEADER_LEN+len,
 807                 GFP_ATOMIC);
 808         if (skb==NULL)
 809                 return;
 810
 811         skb_reserve(skb,dev->hard_header_len);
 812
 813         h = (struct ppp_header *)skb_put(skb, sizeof(struct ppp_header));
 814         h->address = PPP_ALLSTATIONS;        /* broadcast address */
 815         h->control = PPP_UI;                 /* Unnumbered Info */
 816         h->protocol = htons (proto);         /* Link Control Protocol */
 817
 818         lh = (struct lcp_header *)skb_put(skb, sizeof(struct lcp_header));
 819         lh->type = type;
 820         lh->ident = ident;
 821         lh->len = htons (LCP_HEADER_LEN + len);
 822
 823         if (len)
 824                 memcpy(skb_put(skb,len),data, len);
 825
 826         if (sp->pp_flags & PP_DEBUG) {
 827                 printk (KERN_WARNING "%s: %s output <%s id=%xh len=%xh",
 828                         dev->name,
 829                         proto==PPP_LCP ? "lcp" : "ipcp",
 830                         proto==PPP_LCP ? sppp_lcp_type_name (lh->type) :
 831                         sppp_ipcp_type_name (lh->type), lh->ident,
 832                         ntohs (lh->len));
 833                 if (len)
 834                         sppp_print_bytes ((u8*) (lh+1), len);
 835                 printk (">\n");
 836         }
 837         sp->obytes += skb->len;
 838         /* Control is high priority so it doesn't get queued behind data */
 839         skb->priority=TC_PRIO_CONTROL;
 840         skb->dev = dev;
 841         skb_queue_tail(&tx_queue, skb);
 842 }
 843
 844 /*
 845  * Send Cisco keepalive packet.
 846  */
 847
 848 static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2)
 849 {
 850         struct ppp_header *h;
 851         struct cisco_packet *ch;
 852         struct sk_buff *skb;
 853         struct net_device *dev = sp->pp_if;
 854         u32 t = jiffies * 1000/HZ;
 855
 856         skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+CISCO_PACKET_LEN,
 857                 GFP_ATOMIC);
 858
 859         if(skb==NULL)
 860                 return;
 861
 862         skb_reserve(skb, dev->hard_header_len);
 863         h = (struct ppp_header *)skb_put (skb, sizeof(struct ppp_header));
 864         h->address = CISCO_MULTICAST;
 865         h->control = 0;
 866         h->protocol = htons (CISCO_KEEPALIVE);
 867
 868         ch = (struct cisco_packet*)skb_put(skb, CISCO_PACKET_LEN);
 869         ch->type = htonl (type);
 870         ch->par1 = htonl (par1);
 871         ch->par2 = htonl (par2);
 872         ch->rel = -1;
 873         ch->time0 = htons ((u16) (t >> 16));
 874         ch->time1 = htons ((u16) t);
 875
 876         if (sp->pp_flags & PP_DEBUG)
 877                 printk (KERN_WARNING "%s: cisco output: <%xh %xh %xh %xh %xh-%xh>\n",
 878                         dev->name,  ntohl (ch->type), ch->par1,
 879                         ch->par2, ch->rel, ch->time0, ch->time1);
 880         sp->obytes += skb->len;
 881         skb->priority=TC_PRIO_CONTROL;
 882         skb->dev = dev;
 883         skb_queue_tail(&tx_queue, skb);
 884 }
 885
 886 /**
 887  *      sppp_close - close down a synchronous PPP or Cisco HDLC link
 888  *      @dev: The network device to drop the link of
 889  *
 890  *      This drops the logical interface to the channel. It is not
 891  *      done politely as we assume we will also be dropping DTR. Any
 892  *      timeouts are killed.
 893  */
 894
 895 int sppp_close (struct net_device *dev)
 896 {
 897         struct sppp *sp = (struct sppp *)sppp_of(dev);
 898         unsigned long flags;
 899
 900         spin_lock_irqsave(&sp->lock, flags);
 901         sp->pp_link_state = SPPP_LINK_DOWN;
 902         sp->lcp.state = LCP_STATE_CLOSED;
 903         sp->ipcp.state = IPCP_STATE_CLOSED;
 904         sppp_clear_timeout (sp);
 905         spin_unlock_irqrestore(&sp->lock, flags);
 906
 907         return 0;
 908 }
 909
 910 EXPORT_SYMBOL(sppp_close);
 911
 912 /**
 913  *      sppp_open - open a synchronous PPP or Cisco HDLC link
 914  *      @dev:   Network device to activate
 915  *
 916  *      Close down any existing synchronous session and commence
 917  *      from scratch. In the PPP case this means negotiating LCP/IPCP
 918  *      and friends, while for Cisco HDLC we simply need to start sending
 919  *      keepalives
 920  */
 921
 922 int sppp_open (struct net_device *dev)
 923 {
 924         struct sppp *sp = (struct sppp *)sppp_of(dev);
 925         unsigned long flags;
 926
 927         sppp_close(dev);
 928
 929         spin_lock_irqsave(&sp->lock, flags);
 930         if (!(sp->pp_flags & PP_CISCO)) {
 931                 sppp_lcp_open (sp);
 932         }
 933         sp->pp_link_state = SPPP_LINK_DOWN;
 934         spin_unlock_irqrestore(&sp->lock, flags);
 935         sppp_flush_xmit();
 936
 937         return 0;
 938 }
 939
 940 EXPORT_SYMBOL(sppp_open);
 941
 942 /**
 943  *      sppp_reopen - notify of physical link loss
 944  *      @dev: Device that lost the link
 945  *
 946  *      This function informs the synchronous protocol code that
 947  *      the underlying link died (for example a carrier drop on X.21)
 948  *
 949  *      We increment the magic numbers to ensure that if the other end
 950  *      failed to notice we will correctly start a new session. It happens
 951  *      do to the nature of telco circuits is that you can lose carrier on
 952  *      one endonly.
 953  *
 954  *      Having done this we go back to negotiating. This function may
 955  *      be called from an interrupt context.
 956  */
 957
 958 int sppp_reopen (struct net_device *dev)
 959 {
 960         struct sppp *sp = (struct sppp *)sppp_of(dev);
 961         unsigned long flags;
 962
 963         sppp_close(dev);
 964
 965         spin_lock_irqsave(&sp->lock, flags);
 966         if (!(sp->pp_flags & PP_CISCO))
 967         {
 968                 sp->lcp.magic = jiffies;
 969                 ++sp->pp_seq;
 970                 sp->lcp.state = LCP_STATE_CLOSED;
 971                 sp->ipcp.state = IPCP_STATE_CLOSED;
 972                 /* Give it a moment for the line to settle then go */
 973                 sppp_set_timeout (sp, 1);
 974         }
 975         sp->pp_link_state=SPPP_LINK_DOWN;
 976         spin_unlock_irqrestore(&sp->lock, flags);
 977
 978         return 0;
 979 }
 980
 981 EXPORT_SYMBOL(sppp_reopen);
 982
 983 /**
 984  *      sppp_change_mtu - Change the link MTU
 985  *      @dev:   Device to change MTU on
 986  *      @new_mtu: New MTU
 987  *
 988  *      Change the MTU on the link. This can only be called with
 989  *      the link down. It returns an error if the link is up or
 990  *      the mtu is out of range.
 991  */
 992
 993 int sppp_change_mtu(struct net_device *dev, int new_mtu)
 994 {
 995         if(new_mtu<128||new_mtu>PPP_MTU||(dev->flags&IFF_UP))
 996                 return -EINVAL;
 997         dev->mtu=new_mtu;
 998         return 0;
 999 }
1000
1001 EXPORT_SYMBOL(sppp_change_mtu);
1002
1003 /**
1004  *      sppp_do_ioctl - Ioctl handler for ppp/hdlc
1005  *      @dev: Device subject to ioctl
1006  *      @ifr: Interface request block from the user
1007  *      @cmd: Command that is being issued
1008  *
1009  *      This function handles the ioctls that may be issued by the user
1010  *      to control the settings of a PPP/HDLC link. It does both busy
1011  *      and security checks. This function is intended to be wrapped by
1012  *      callers who wish to add additional ioctl calls of their own.
1013  */
1014
1015 int sppp_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1016 {
1017         struct sppp *sp = (struct sppp *)sppp_of(dev);
1018
1019         if(dev->flags&IFF_UP)
1020                 return -EBUSY;
1021
1022         if(!capable(CAP_NET_ADMIN))
1023                 return -EPERM;
1024
1025         switch(cmd)
1026         {
1027                 case SPPPIOCCISCO:
1028                         sp->pp_flags|=PP_CISCO;
1029                         dev->type = ARPHRD_HDLC;
1030                         break;
1031                 case SPPPIOCPPP:
1032                         sp->pp_flags&=~PP_CISCO;
1033                         dev->type = ARPHRD_PPP;
1034                         break;
1035                 case SPPPIOCDEBUG:
1036                         sp->pp_flags&=~PP_DEBUG;
1037                         if(ifr->ifr_flags)
1038                                 sp->pp_flags|=PP_DEBUG;
1039                         break;
1040                 case SPPPIOCGFLAGS:
1041                         if(copy_to_user(ifr->ifr_data, &sp->pp_flags, sizeof(sp->pp_flags)))
1042                                 return -EFAULT;
1043                         break;
1044                 case SPPPIOCSFLAGS:
1045                         if(copy_from_user(&sp->pp_flags, ifr->ifr_data, sizeof(sp->pp_flags)))
1046                                 return -EFAULT;
1047                         break;
1048                 default:
1049                         return -EINVAL;
1050         }
1051         return 0;
1052 }
1053
1054 EXPORT_SYMBOL(sppp_do_ioctl);
1055
1056 /**
1057  *      sppp_attach - attach synchronous PPP/HDLC to a device
1058  *      @pd:    PPP device to initialise
1059  *
1060  *      This initialises the PPP/HDLC support on an interface. At the
1061  *      time of calling the dev element must point to the network device
1062  *      that this interface is attached to. The interface should not yet
1063  *      be registered.
1064  */
1065
1066 void sppp_attach(struct ppp_device *pd)
1067 {
1068         struct net_device *dev = pd->dev;
1069         struct sppp *sp = &pd->sppp;
1070         unsigned long flags;
1071
1072         /* Make sure embedding is safe for sppp_of */
1073         BUG_ON(sppp_of(dev) != sp);
1074
1075         spin_lock_irqsave(&spppq_lock, flags);
1076         /* Initialize keepalive handler. */
1077         if (! spppq)
1078         {
1079                 init_timer(&sppp_keepalive_timer);
1080                 sppp_keepalive_timer.expires=jiffies+10*HZ;
1081                 sppp_keepalive_timer.function=sppp_keepalive;
1082                 add_timer(&sppp_keepalive_timer);
1083         }
1084         /* Insert new entry into the keepalive list. */
1085         sp->pp_next = spppq;
1086         spppq = sp;
1087         spin_unlock_irqrestore(&spppq_lock, flags);
1088
1089         sp->pp_loopcnt = 0;
1090         sp->pp_alivecnt = 0;
1091         sp->pp_seq = 0;
1092         sp->pp_rseq = 0;
1093         sp->pp_flags = PP_KEEPALIVE|PP_CISCO|debug;/*PP_DEBUG;*/
1094         sp->lcp.magic = 0;
1095         sp->lcp.state = LCP_STATE_CLOSED;
1096         sp->ipcp.state = IPCP_STATE_CLOSED;
1097         sp->pp_if = dev;
1098         spin_lock_init(&sp->lock);
1099
1100         /*
1101          *      Device specific setup. All but interrupt handler and
1102          *      hard_start_xmit.
1103          */
1104
1105         dev->hard_header = sppp_hard_header;
1106         dev->rebuild_header = sppp_rebuild_header;
1107         dev->tx_queue_len = 10;
1108         dev->type = ARPHRD_HDLC;
1109         dev->addr_len = 0;
1110         dev->hard_header_len = sizeof(struct ppp_header);
1111         dev->mtu = PPP_MTU;
1112         /*
1113          *      These 4 are callers but MUST also call sppp_ functions
1114          */
1115         dev->do_ioctl = sppp_do_ioctl;
1116 #if 0
1117         dev->get_stats = NULL;          /* Let the driver override these */
1118         dev->open = sppp_open;
1119         dev->stop = sppp_close;
1120 #endif
1121         dev->change_mtu = sppp_change_mtu;
1122         dev->hard_header_cache = NULL;
1123         dev->header_cache_update = NULL;
1124         dev->flags = IFF_MULTICAST|IFF_POINTOPOINT|IFF_NOARP;
1125 }
1126
1127 EXPORT_SYMBOL(sppp_attach);
1128
1129 /**
1130  *      sppp_detach - release PPP resources from a device
1131  *      @dev:   Network device to release
1132  *
1133  *      Stop and free up any PPP/HDLC resources used by this
1134  *      interface. This must be called before the device is
1135  *      freed.
1136  */
1137
1138 void sppp_detach (struct net_device *dev)
1139 {
1140         struct sppp **q, *p, *sp = (struct sppp *)sppp_of(dev);
1141         unsigned long flags;
1142
1143         spin_lock_irqsave(&spppq_lock, flags);
1144         /* Remove the entry from the keepalive list. */
1145         for (q = &spppq; (p = *q); q = &p->pp_next)
1146                 if (p == sp) {
1147                         *q = p->pp_next;
1148                         break;
1149                 }
1150
1151         /* Stop keepalive handler. */
1152         if (! spppq)
1153                 del_timer(&sppp_keepalive_timer);
1154         sppp_clear_timeout (sp);
1155         spin_unlock_irqrestore(&spppq_lock, flags);
1156 }
1157
1158 EXPORT_SYMBOL(sppp_detach);
1159
1160 /*
1161  * Analyze the LCP Configure-Request options list
1162  * for the presence of unknown options.
1163  * If the request contains unknown options, build and
1164  * send Configure-reject packet, containing only unknown options.
1165  */
1166 static int
1167 sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
1168         int len, u32 *magic)
1169 {
1170         u8 *buf, *r, *p;
1171         int rlen;
1172
1173         len -= 4;
1174         buf = r = kmalloc (len, GFP_ATOMIC);
1175         if (! buf)
1176                 return (0);
1177
1178         p = (void*) (h+1);
1179         for (rlen=0; len>1 && p[1]; len-=p[1], p+=p[1]) {
1180                 switch (*p) {
1181                 case LCP_OPT_MAGIC:
1182                         /* Magic number -- extract. */
1183                         if (len >= 6 && p[1] == 6) {
1184                                 *magic = (u32)p[2] << 24 |
1185                                         (u32)p[3] << 16 | p[4] << 8 | p[5];
1186                                 continue;
1187                         }
1188                         break;
1189                 case LCP_OPT_ASYNC_MAP:
1190                         /* Async control character map -- check to be zero. */
1191                         if (len >= 6 && p[1] == 6 && ! p[2] && ! p[3] &&
1192                             ! p[4] && ! p[5])
1193                                 continue;
1194                         break;
1195                 case LCP_OPT_MRU:
1196                         /* Maximum receive unit -- always OK. */
1197                         continue;
1198                 default:
1199                         /* Others not supported. */
1200                         break;
1201                 }
1202                 /* Add the option to rejected list. */
1203                 memcpy(r, p, p[1]);
1204                 r += p[1];
1205                 rlen += p[1];
1206         }
1207         if (rlen)
1208                 sppp_cp_send (sp, PPP_LCP, LCP_CONF_REJ, h->ident, rlen, buf);
1209         kfree(buf);
1210         return (rlen == 0);
1211 }
1212
1213 static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *skb)
1214 {
1215         struct lcp_header *h;
1216         struct net_device *dev = sp->pp_if;
1217         int len = skb->len;
1218
1219         if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
1220                 if (sp->pp_flags & PP_DEBUG)
1221                         printk (KERN_WARNING "%s: invalid ipcp packet length: %d bytes\n",
1222                                 dev->name,  len);
1223                 return;
1224         }
1225         h = (struct lcp_header *)skb->data;
1226         skb_pull(skb,sizeof(struct lcp_header));
1227         if (sp->pp_flags & PP_DEBUG) {
1228                 printk (KERN_WARNING "%s: ipcp input: %d bytes <%s id=%xh len=%xh",
1229                         dev->name,  len,
1230                         sppp_ipcp_type_name (h->type), h->ident, ntohs (h->len));
1231                 if (len > 4)
1232                         sppp_print_bytes ((u8*) (h+1), len-4);
1233                 printk (">\n");
1234         }
1235         if (len > ntohs (h->len))
1236                 len = ntohs (h->len);
1237         switch (h->type) {
1238         default:
1239                 /* Unknown packet type -- send Code-Reject packet. */
1240                 sppp_cp_send (sp, PPP_IPCP, IPCP_CODE_REJ, ++sp->pp_seq, len, h);
1241                 break;
1242         case IPCP_CONF_REQ:
1243                 if (len < 4) {
1244                         if (sp->pp_flags & PP_DEBUG)
1245                                 printk (KERN_WARNING "%s: invalid ipcp configure request packet length: %d bytes\n",
1246                                         dev->name, len);
1247                         return;
1248                 }
1249                 if (len > 4) {
1250                         sppp_cp_send (sp, PPP_IPCP, LCP_CONF_REJ, h->ident,
1251                                 len-4, h+1);
1252
1253                         switch (sp->ipcp.state) {
1254                         case IPCP_STATE_OPENED:
1255                                 /* Initiate renegotiation. */
1256                                 sppp_ipcp_open (sp);
1257                                 /* fall through... */
1258                         case IPCP_STATE_ACK_SENT:
1259                                 /* Go to closed state. */
1260                                 sp->ipcp.state = IPCP_STATE_CLOSED;
1261                         }
1262                 } else {
1263                         /* Send Configure-Ack packet. */
1264                         sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_ACK, h->ident,
1265                                 0, NULL);
1266                         /* Change the state. */
1267                         if (sp->ipcp.state == IPCP_STATE_ACK_RCVD)
1268                                 sp->ipcp.state = IPCP_STATE_OPENED;
1269                         else
1270                                 sp->ipcp.state = IPCP_STATE_ACK_SENT;
1271                 }
1272                 break;
1273         case IPCP_CONF_ACK:
1274                 if (h->ident != sp->ipcp.confid)
1275                         break;
1276                 sppp_clear_timeout (sp);
1277                 switch (sp->ipcp.state) {
1278                 case IPCP_STATE_CLOSED:
1279                         sp->ipcp.state = IPCP_STATE_ACK_RCVD;
1280                         sppp_set_timeout (sp, 5);
1281                         break;
1282                 case IPCP_STATE_ACK_SENT:
1283                         sp->ipcp.state = IPCP_STATE_OPENED;
1284                         break;
1285                 }
1286                 break;
1287         case IPCP_CONF_NAK:
1288         case IPCP_CONF_REJ:
1289                 if (h->ident != sp->ipcp.confid)
1290                         break;
1291                 sppp_clear_timeout (sp);
1292                         /* Initiate renegotiation. */
1293                 sppp_ipcp_open (sp);
1294                 if (sp->ipcp.state != IPCP_STATE_ACK_SENT)
1295                         /* Go to closed state. */
1296                         sp->ipcp.state = IPCP_STATE_CLOSED;
1297                 break;
1298         case IPCP_TERM_REQ:
1299                 /* Send Terminate-Ack packet. */
1300                 sppp_cp_send (sp, PPP_IPCP, IPCP_TERM_ACK, h->ident, 0, NULL);
1301                 /* Go to closed state. */
1302                 sp->ipcp.state = IPCP_STATE_CLOSED;
1303                 /* Initiate renegotiation. */
1304                 sppp_ipcp_open (sp);
1305                 break;
1306         case IPCP_TERM_ACK:
1307                 /* Ignore for now. */
1308         case IPCP_CODE_REJ:
1309                 /* Ignore for now. */
1310                 break;
1311         }
1312 }
1313
1314 static void sppp_lcp_open (struct sppp *sp)
1315 {
1316         char opt[6];
1317
1318         if (! sp->lcp.magic)
1319                 sp->lcp.magic = jiffies;
1320         opt[0] = LCP_OPT_MAGIC;
1321         opt[1] = sizeof (opt);
1322         opt[2] = sp->lcp.magic >> 24;
1323         opt[3] = sp->lcp.magic >> 16;
1324         opt[4] = sp->lcp.magic >> 8;
1325         opt[5] = sp->lcp.magic;
1326         sp->lcp.confid = ++sp->pp_seq;
1327         sppp_cp_send (sp, PPP_LCP, LCP_CONF_REQ, sp->lcp.confid,
1328                 sizeof (opt), &opt);
1329         sppp_set_timeout (sp, 2);
1330 }
1331
1332 static void sppp_ipcp_open (struct sppp *sp)
1333 {
1334         sp->ipcp.confid = ++sp->pp_seq;
1335         sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_REQ, sp->ipcp.confid, 0, NULL);
1336         sppp_set_timeout (sp, 2);
1337 }
1338
1339 /*
1340  * Process PPP control protocol timeouts.
1341  */
1342
1343 static void sppp_cp_timeout (unsigned long arg)
1344 {
1345         struct sppp *sp = (struct sppp*) arg;
1346         unsigned long flags;
1347
1348         spin_lock_irqsave(&sp->lock, flags);
1349
1350         sp->pp_flags &= ~PP_TIMO;
1351         if (! (sp->pp_if->flags & IFF_UP) || (sp->pp_flags & PP_CISCO)) {
1352                 spin_unlock_irqrestore(&sp->lock, flags);
1353                 return;
1354         }
1355         switch (sp->lcp.state) {
1356         case LCP_STATE_CLOSED:
1357                 /* No ACK for Configure-Request, retry. */
1358                 sppp_lcp_open (sp);
1359                 break;
1360         case LCP_STATE_ACK_RCVD:
1361                 /* ACK got, but no Configure-Request for peer, retry. */
1362                 sppp_lcp_open (sp);
1363                 sp->lcp.state = LCP_STATE_CLOSED;
1364                 break;
1365         case LCP_STATE_ACK_SENT:
1366                 /* ACK sent but no ACK for Configure-Request, retry. */
1367                 sppp_lcp_open (sp);
1368                 break;
1369         case LCP_STATE_OPENED:
1370                 /* LCP is already OK, try IPCP. */
1371                 switch (sp->ipcp.state) {
1372                 case IPCP_STATE_CLOSED:
1373                         /* No ACK for Configure-Request, retry. */
1374                         sppp_ipcp_open (sp);
1375                         break;
1376                 case IPCP_STATE_ACK_RCVD:
1377                         /* ACK got, but no Configure-Request for peer, retry. */
1378                         sppp_ipcp_open (sp);
1379                         sp->ipcp.state = IPCP_STATE_CLOSED;
1380                         break;
1381                 case IPCP_STATE_ACK_SENT:
1382                         /* ACK sent but no ACK for Configure-Request, retry. */
1383                         sppp_ipcp_open (sp);
1384                         break;
1385                 case IPCP_STATE_OPENED:
1386                         /* IPCP is OK. */
1387                         break;
1388                 }
1389                 break;
1390         }
1391         spin_unlock_irqrestore(&sp->lock, flags);
1392         sppp_flush_xmit();
1393 }
1394
1395 static char *sppp_lcp_type_name (u8 type)
1396 {
1397         static char buf [8];
1398         switch (type) {
1399         case LCP_CONF_REQ:   return ("conf-req");
1400         case LCP_CONF_ACK:   return ("conf-ack");
1401         case LCP_CONF_NAK:   return ("conf-nack");
1402         case LCP_CONF_REJ:   return ("conf-rej");
1403         case LCP_TERM_REQ:   return ("term-req");
1404         case LCP_TERM_ACK:   return ("term-ack");
1405         case LCP_CODE_REJ:   return ("code-rej");
1406         case LCP_PROTO_REJ:  return ("proto-rej");
1407         case LCP_ECHO_REQ:   return ("echo-req");
1408         case LCP_ECHO_REPLY: return ("echo-reply");
1409         case LCP_DISC_REQ:   return ("discard-req");
1410         }
1411         sprintf (buf, "%xh", type);
1412         return (buf);
1413 }
1414
1415 static char *sppp_ipcp_type_name (u8 type)
1416 {
1417         static char buf [8];
1418         switch (type) {
1419         case IPCP_CONF_REQ:   return ("conf-req");
1420         case IPCP_CONF_ACK:   return ("conf-ack");
1421         case IPCP_CONF_NAK:   return ("conf-nack");
1422         case IPCP_CONF_REJ:   return ("conf-rej");
1423         case IPCP_TERM_REQ:   return ("term-req");
1424         case IPCP_TERM_ACK:   return ("term-ack");
1425         case IPCP_CODE_REJ:   return ("code-rej");
1426         }
1427         sprintf (buf, "%xh", type);
1428         return (buf);
1429 }
1430
1431 static void sppp_print_bytes (u_char *p, u16 len)
1432 {
1433         printk (" %x", *p++);
1434         while (--len > 0)
1435                 printk ("-%x", *p++);
1436 }
1437
1438 /**
1439  *      sppp_rcv -      receive and process a WAN PPP frame
1440  *      @skb:   The buffer to process
1441  *      @dev:   The device it arrived on
1442  *      @p: Unused
1443  *
1444  *      Protocol glue. This drives the deferred processing mode the poorer
1445  *      cards use. This can be called directly by cards that do not have
1446  *      timing constraints but is normally called from the network layer
1447  *      after interrupt servicing to process frames queued via netif_rx.
1448  */
1449
1450 static int sppp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *p)
1451 {
1452         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
1453                 return NET_RX_DROP;
1454         sppp_input(dev,skb);
1455         return 0;
1456 }
1457
1458 struct packet_type sppp_packet_type = {
1459         .type   = __constant_htons(ETH_P_WAN_PPP),
1460         .func   = sppp_rcv,
1461 };
1462
1463 static char banner[] __initdata =
1464         KERN_INFO "Cronyx Ltd, Synchronous PPP and CISCO HDLC (c) 1994\n"
1465         KERN_INFO "Linux port (c) 1998 Building Number Three Ltd & "
1466                   "Jan \"Yenya\" Kasprzak.\n";
1467
1468 static int __init sync_ppp_init(void)
1469 {
1470         if(debug)
1471                 debug=PP_DEBUG;
1472         printk(banner);
1473         skb_queue_head_init(&tx_queue);
1474         dev_add_pack(&sppp_packet_type);
1475         return 0;
1476 }
1477
1478
1479 static void __exit sync_ppp_cleanup(void)
1480 {
1481         dev_remove_pack(&sppp_packet_type);
1482 }
1483
1484 module_init(sync_ppp_init);
1485 module_exit(sync_ppp_cleanup);
1486 module_param(debug, int, 0);
1487 MODULE_LICENSE("GPL");
1488