linux/drivers/net/wan/hdlc_ppp.c
<<
>>
Prefs
   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 <khc@pm.waw.pl>
   7 */
   8
   9#include <linux/errno.h>
  10#include <linux/hdlc.h>
  11#include <linux/if_arp.h>
  12#include <linux/inetdevice.h>
  13#include <linux/init.h>
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/pkt_sched.h>
  17#include <linux/poll.h>
  18#include <linux/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
  35enum {IDX_LCP = 0, IDX_IPCP, IDX_IPV6CP, IDX_COUNT};
  36enum {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
  40static const char *const code_names[CP_CODES] = {
  41        "0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
  42        "TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
  43};
  44
  45static char debug_buffer[64 + 3 * DEBUG_CP];
  46#endif
  47
  48enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
  49
  50struct hdlc_header {
  51        u8 address;
  52        u8 control;
  53        __be16 protocol;
  54};
  55
  56struct cp_header {
  57        u8 code;
  58        u8 id;
  59        __be16 len;
  60};
  61
  62struct 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
  72struct 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
  82enum {CLOSED = 0, STOPPED, STOPPING, REQ_SENT, ACK_RECV, ACK_SENT, OPENED,
  83      STATES, STATE_MASK = 0xF};
  84enum {START = 0, STOP, TO_GOOD, TO_BAD, RCR_GOOD, RCR_BAD, RCA, RCN, RTR, RTA,
  85      RUC, RXJ_GOOD, RXJ_BAD, EVENTS};
  86enum {INV = 0x10, IRC = 0x20, ZRC = 0x40, SCR = 0x80, SCA = 0x100,
  87      SCN = 0x200, STR = 0x400, STA = 0x800, SCJ = 0x1000};
  88
  89#if DEBUG_STATE
  90static const char *const state_names[STATES] = {
  91        "Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
  92        "Opened"
  93};
  94
  95static const char *const event_names[EVENTS] = {
  96        "Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
  97        "RTR", "RTA", "RUC", "RXJ+", "RXJ-"
  98};
  99#endif
 100
 101static struct sk_buff_head tx_queue; /* used when holding the spin lock */
 102
 103static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs);
 104
 105static inline struct ppp *get_ppp(struct net_device *dev)
 106{
 107        return (struct ppp *)dev_to_hdlc(dev)->state;
 108}
 109
 110static inline struct proto *get_proto(struct net_device *dev, u16 pid)
 111{
 112        struct ppp *ppp = get_ppp(dev);
 113
 114        switch (pid) {
 115        case PID_LCP:
 116                return &ppp->protos[IDX_LCP];
 117        case PID_IPCP:
 118                return &ppp->protos[IDX_IPCP];
 119        case PID_IPV6CP:
 120                return &ppp->protos[IDX_IPV6CP];
 121        default:
 122                return NULL;
 123        }
 124}
 125
 126static inline const char *proto_name(u16 pid)
 127{
 128        switch (pid) {
 129        case PID_LCP:
 130                return "LCP";
 131        case PID_IPCP:
 132                return "IPCP";
 133        case PID_IPV6CP:
 134                return "IPV6CP";
 135        default:
 136                return NULL;
 137        }
 138}
 139
 140static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
 141{
 142        struct hdlc_header *data = (struct hdlc_header *)skb->data;
 143
 144        if (skb->len < sizeof(struct hdlc_header))
 145                return htons(ETH_P_HDLC);
 146        if (data->address != HDLC_ADDR_ALLSTATIONS ||
 147            data->control != HDLC_CTRL_UI)
 148                return htons(ETH_P_HDLC);
 149
 150        switch (data->protocol) {
 151        case cpu_to_be16(PID_IP):
 152                skb_pull(skb, sizeof(struct hdlc_header));
 153                return htons(ETH_P_IP);
 154
 155        case cpu_to_be16(PID_IPV6):
 156                skb_pull(skb, sizeof(struct hdlc_header));
 157                return htons(ETH_P_IPV6);
 158
 159        default:
 160                return htons(ETH_P_HDLC);
 161        }
 162}
 163
 164static 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
 196static void ppp_tx_flush(void)
 197{
 198        struct sk_buff *skb;
 199
 200        while ((skb = skb_dequeue(&tx_queue)) != NULL)
 201                dev_queue_xmit(skb);
 202}
 203
 204static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
 205                      u8 id, unsigned int len, const void *data)
 206{
 207        struct sk_buff *skb;
 208        struct cp_header *cp;
 209        unsigned int magic_len = 0;
 210        static u32 magic;
 211
 212#if DEBUG_CP
 213        int i;
 214        char *ptr;
 215#endif
 216
 217        if (pid == PID_LCP && (code == LCP_ECHO_REQ || code == LCP_ECHO_REPLY))
 218                magic_len = sizeof(magic);
 219
 220        skb = dev_alloc_skb(sizeof(struct hdlc_header) +
 221                            sizeof(struct cp_header) + magic_len + len);
 222        if (!skb)
 223                return;
 224
 225        skb_reserve(skb, sizeof(struct hdlc_header));
 226
 227        cp = skb_put(skb, sizeof(struct cp_header));
 228        cp->code = code;
 229        cp->id = id;
 230        cp->len = htons(sizeof(struct cp_header) + magic_len + len);
 231
 232        if (magic_len)
 233                skb_put_data(skb, &magic, magic_len);
 234        if (len)
 235                skb_put_data(skb, data, len);
 236
 237#if DEBUG_CP
 238        BUG_ON(code >= CP_CODES);
 239        ptr = debug_buffer;
 240        *ptr = '\x0';
 241        for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
 242                sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
 243                ptr += strlen(ptr);
 244        }
 245        printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
 246               proto_name(pid), code_names[code], id, debug_buffer);
 247#endif
 248
 249        ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
 250
 251        skb->priority = TC_PRIO_CONTROL;
 252        skb->dev = dev;
 253        skb->protocol = htons(ETH_P_HDLC);
 254        skb_reset_network_header(skb);
 255        skb_queue_tail(&tx_queue, skb);
 256}
 257
 258/* State transition table (compare STD-51)
 259   Events                                   Actions
 260   TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
 261   TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
 262
 263   RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
 264   RCR- = Receive-Configure-Request (Bad)
 265   RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
 266   RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
 267
 268   RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
 269   RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
 270
 271   RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
 272   RXJ+ = Receive-Code-Reject (permitted)
 273       or Receive-Protocol-Reject
 274   RXJ- = Receive-Code-Reject (catastrophic)
 275       or Receive-Protocol-Reject
 276*/
 277static int cp_table[EVENTS][STATES] = {
 278        /* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
 279             0           1         2       3       4      5          6    */
 280        {IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
 281        {   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
 282        {   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
 283        {   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
 284        {  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
 285        {  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
 286        {  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
 287        {  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
 288        {  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
 289        {    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
 290        {  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
 291        {    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
 292        {    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
 293};
 294
 295/* SCA: RCR+ must supply id, len and data
 296   SCN: RCR- must supply code, id, len and data
 297   STA: RTR must supply id
 298   SCJ: RUC must supply CP packet len and data */
 299static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
 300                         u8 id, unsigned int len, const void *data)
 301{
 302        int old_state, action;
 303        struct ppp *ppp = get_ppp(dev);
 304        struct proto *proto = get_proto(dev, pid);
 305
 306        old_state = proto->state;
 307        BUG_ON(old_state >= STATES);
 308        BUG_ON(event >= EVENTS);
 309
 310#if DEBUG_STATE
 311        printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
 312               proto_name(pid), event_names[event], state_names[proto->state]);
 313#endif
 314
 315        action = cp_table[event][old_state];
 316
 317        proto->state = action & STATE_MASK;
 318        if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
 319                mod_timer(&proto->timer, proto->timeout =
 320                          jiffies + ppp->req_timeout * HZ);
 321        if (action & ZRC)
 322                proto->restart_counter = 0;
 323        if (action & IRC)
 324                proto->restart_counter = (proto->state == STOPPING) ?
 325                        ppp->term_retries : ppp->cr_retries;
 326
 327        if (action & SCR)       /* send Configure-Request */
 328                ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
 329                          0, NULL);
 330        if (action & SCA)       /* send Configure-Ack */
 331                ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
 332        if (action & SCN)       /* send Configure-Nak/Reject */
 333                ppp_tx_cp(dev, pid, code, id, len, data);
 334        if (action & STR)       /* send Terminate-Request */
 335                ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
 336        if (action & STA)       /* send Terminate-Ack */
 337                ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
 338        if (action & SCJ)       /* send Code-Reject */
 339                ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
 340
 341        if (old_state != OPENED && proto->state == OPENED) {
 342                netdev_info(dev, "%s up\n", proto_name(pid));
 343                if (pid == PID_LCP) {
 344                        netif_dormant_off(dev);
 345                        ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
 346                        ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
 347                        ppp->last_pong = jiffies;
 348                        mod_timer(&proto->timer, proto->timeout =
 349                                  jiffies + ppp->keepalive_interval * HZ);
 350                }
 351        }
 352        if (old_state == OPENED && proto->state != OPENED) {
 353                netdev_info(dev, "%s down\n", proto_name(pid));
 354                if (pid == PID_LCP) {
 355                        netif_dormant_on(dev);
 356                        ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
 357                        ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
 358                }
 359        }
 360        if (old_state != CLOSED && proto->state == CLOSED)
 361                del_timer(&proto->timer);
 362
 363#if DEBUG_STATE
 364        printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
 365               proto_name(pid), event_names[event], state_names[proto->state]);
 366#endif
 367}
 368
 369static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
 370                            unsigned int req_len, const u8 *data)
 371{
 372        static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
 373        const u8 *opt;
 374        u8 *out;
 375        unsigned int len = req_len, nak_len = 0, rej_len = 0;
 376
 377        out = kmalloc(len, GFP_ATOMIC);
 378        if (!out) {
 379                dev->stats.rx_dropped++;
 380                return; /* out of memory, ignore CR packet */
 381        }
 382
 383        for (opt = data; len; len -= opt[1], opt += opt[1]) {
 384                if (len < 2 || opt[1] < 2 || len < opt[1])
 385                        goto err_out;
 386
 387                if (pid == PID_LCP)
 388                        switch (opt[0]) {
 389                        case LCP_OPTION_MRU:
 390                                continue; /* MRU always OK and > 1500 bytes? */
 391
 392                        case LCP_OPTION_ACCM: /* async control character map */
 393                                if (opt[1] < sizeof(valid_accm))
 394                                        goto err_out;
 395                                if (!memcmp(opt, valid_accm,
 396                                            sizeof(valid_accm)))
 397                                        continue;
 398                                if (!rej_len) { /* NAK it */
 399                                        memcpy(out + nak_len, valid_accm,
 400                                               sizeof(valid_accm));
 401                                        nak_len += sizeof(valid_accm);
 402                                        continue;
 403                                }
 404                                break;
 405                        case LCP_OPTION_MAGIC:
 406                                if (len < 6)
 407                                        goto err_out;
 408                                if (opt[1] != 6 || (!opt[2] && !opt[3] &&
 409                                                    !opt[4] && !opt[5]))
 410                                        break; /* reject invalid magic number */
 411                                continue;
 412                        }
 413                /* reject this option */
 414                memcpy(out + rej_len, opt, opt[1]);
 415                rej_len += opt[1];
 416        }
 417
 418        if (rej_len)
 419                ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
 420        else if (nak_len)
 421                ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
 422        else
 423                ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
 424
 425        kfree(out);
 426        return;
 427
 428err_out:
 429        dev->stats.rx_errors++;
 430        kfree(out);
 431}
 432
 433static int ppp_rx(struct sk_buff *skb)
 434{
 435        struct hdlc_header *hdr = (struct hdlc_header *)skb->data;
 436        struct net_device *dev = skb->dev;
 437        struct ppp *ppp = get_ppp(dev);
 438        struct proto *proto;
 439        struct cp_header *cp;
 440        unsigned long flags;
 441        unsigned int len;
 442        u16 pid;
 443#if DEBUG_CP
 444        int i;
 445        char *ptr;
 446#endif
 447
 448        spin_lock_irqsave(&ppp->lock, flags);
 449        /* Check HDLC header */
 450        if (skb->len < sizeof(struct hdlc_header))
 451                goto rx_error;
 452        cp = skb_pull(skb, sizeof(struct hdlc_header));
 453        if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
 454            hdr->control != HDLC_CTRL_UI)
 455                goto rx_error;
 456
 457        pid = ntohs(hdr->protocol);
 458        proto = get_proto(dev, pid);
 459        if (!proto) {
 460                if (ppp->protos[IDX_LCP].state == OPENED)
 461                        ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
 462                                  ++ppp->seq, skb->len + 2, &hdr->protocol);
 463                goto rx_error;
 464        }
 465
 466        len = ntohs(cp->len);
 467        if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
 468            skb->len < len /* truncated packet? */)
 469                goto rx_error;
 470        skb_pull(skb, sizeof(struct cp_header));
 471        len -= sizeof(struct cp_header);
 472
 473        /* HDLC and CP headers stripped from skb */
 474#if DEBUG_CP
 475        if (cp->code < CP_CODES)
 476                sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
 477                        cp->id);
 478        else
 479                sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
 480        ptr = debug_buffer + strlen(debug_buffer);
 481        for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
 482                sprintf(ptr, " %02X", skb->data[i]);
 483                ptr += strlen(ptr);
 484        }
 485        printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
 486               debug_buffer);
 487#endif
 488
 489        /* LCP only */
 490        if (pid == PID_LCP)
 491                switch (cp->code) {
 492                case LCP_PROTO_REJ:
 493                        pid = ntohs(*(__be16 *)skb->data);
 494                        if (pid == PID_LCP || pid == PID_IPCP ||
 495                            pid == PID_IPV6CP)
 496                                ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
 497                                             0, NULL);
 498                        goto out;
 499
 500                case LCP_ECHO_REQ: /* send Echo-Reply */
 501                        if (len >= 4 && proto->state == OPENED)
 502                                ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
 503                                          cp->id, len - 4, skb->data + 4);
 504                        goto out;
 505
 506                case LCP_ECHO_REPLY:
 507                        if (cp->id == ppp->echo_id)
 508                                ppp->last_pong = jiffies;
 509                        goto out;
 510
 511                case LCP_DISC_REQ: /* discard */
 512                        goto out;
 513                }
 514
 515        /* LCP, IPCP and IPV6CP */
 516        switch (cp->code) {
 517        case CP_CONF_REQ:
 518                ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
 519                break;
 520
 521        case CP_CONF_ACK:
 522                if (cp->id == proto->cr_id)
 523                        ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
 524                break;
 525
 526        case CP_CONF_REJ:
 527        case CP_CONF_NAK:
 528                if (cp->id == proto->cr_id)
 529                        ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
 530                break;
 531
 532        case CP_TERM_REQ:
 533                ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
 534                break;
 535
 536        case CP_TERM_ACK:
 537                ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
 538                break;
 539
 540        case CP_CODE_REJ:
 541                ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
 542                break;
 543
 544        default:
 545                len += sizeof(struct cp_header);
 546                if (len > dev->mtu)
 547                        len = dev->mtu;
 548                ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
 549                break;
 550        }
 551        goto out;
 552
 553rx_error:
 554        dev->stats.rx_errors++;
 555out:
 556        spin_unlock_irqrestore(&ppp->lock, flags);
 557        dev_kfree_skb_any(skb);
 558        ppp_tx_flush();
 559        return NET_RX_DROP;
 560}
 561
 562static void ppp_timer(struct timer_list *t)
 563{
 564        struct proto *proto = from_timer(proto, t, timer);
 565        struct ppp *ppp = get_ppp(proto->dev);
 566        unsigned long flags;
 567
 568        spin_lock_irqsave(&ppp->lock, flags);
 569        /* mod_timer could be called after we entered this function but
 570         * before we got the lock.
 571         */
 572        if (timer_pending(&proto->timer)) {
 573                spin_unlock_irqrestore(&ppp->lock, flags);
 574                return;
 575        }
 576        switch (proto->state) {
 577        case STOPPING:
 578        case REQ_SENT:
 579        case ACK_RECV:
 580        case ACK_SENT:
 581                if (proto->restart_counter) {
 582                        ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 583                                     0, NULL);
 584                        proto->restart_counter--;
 585                } else if (netif_carrier_ok(proto->dev))
 586                        ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
 587                                     0, NULL);
 588                else
 589                        ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
 590                                     0, NULL);
 591                break;
 592
 593        case OPENED:
 594                if (proto->pid != PID_LCP)
 595                        break;
 596                if (time_after(jiffies, ppp->last_pong +
 597                               ppp->keepalive_timeout * HZ)) {
 598                        netdev_info(proto->dev, "Link down\n");
 599                        ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
 600                        ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
 601                } else {        /* send keep-alive packet */
 602                        ppp->echo_id = ++ppp->seq;
 603                        ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
 604                                  ppp->echo_id, 0, NULL);
 605                        proto->timer.expires = jiffies +
 606                                ppp->keepalive_interval * HZ;
 607                        add_timer(&proto->timer);
 608                }
 609                break;
 610        }
 611        spin_unlock_irqrestore(&ppp->lock, flags);
 612        ppp_tx_flush();
 613}
 614
 615static void ppp_start(struct net_device *dev)
 616{
 617        struct ppp *ppp = get_ppp(dev);
 618        int i;
 619
 620        for (i = 0; i < IDX_COUNT; i++) {
 621                struct proto *proto = &ppp->protos[i];
 622
 623                proto->dev = dev;
 624                timer_setup(&proto->timer, ppp_timer, 0);
 625                proto->state = CLOSED;
 626        }
 627        ppp->protos[IDX_LCP].pid = PID_LCP;
 628        ppp->protos[IDX_IPCP].pid = PID_IPCP;
 629        ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
 630
 631        ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
 632}
 633
 634static void ppp_stop(struct net_device *dev)
 635{
 636        ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
 637}
 638
 639static void ppp_close(struct net_device *dev)
 640{
 641        ppp_tx_flush();
 642}
 643
 644static struct hdlc_proto proto = {
 645        .start          = ppp_start,
 646        .stop           = ppp_stop,
 647        .close          = ppp_close,
 648        .type_trans     = ppp_type_trans,
 649        .ioctl          = ppp_ioctl,
 650        .netif_rx       = ppp_rx,
 651        .module         = THIS_MODULE,
 652};
 653
 654static const struct header_ops ppp_header_ops = {
 655        .create = ppp_hard_header,
 656};
 657
 658static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs)
 659{
 660        hdlc_device *hdlc = dev_to_hdlc(dev);
 661        struct ppp *ppp;
 662        int result;
 663
 664        switch (ifs->type) {
 665        case IF_GET_PROTO:
 666                if (dev_to_hdlc(dev)->proto != &proto)
 667                        return -EINVAL;
 668                ifs->type = IF_PROTO_PPP;
 669                return 0; /* return protocol only, no settable parameters */
 670
 671        case IF_PROTO_PPP:
 672                if (!capable(CAP_NET_ADMIN))
 673                        return -EPERM;
 674
 675                if (dev->flags & IFF_UP)
 676                        return -EBUSY;
 677
 678                /* no settable parameters */
 679
 680                result = hdlc->attach(dev, ENCODING_NRZ,
 681                                      PARITY_CRC16_PR1_CCITT);
 682                if (result)
 683                        return result;
 684
 685                result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
 686                if (result)
 687                        return result;
 688
 689                ppp = get_ppp(dev);
 690                spin_lock_init(&ppp->lock);
 691                ppp->req_timeout = 2;
 692                ppp->cr_retries = 10;
 693                ppp->term_retries = 2;
 694                ppp->keepalive_interval = 10;
 695                ppp->keepalive_timeout = 60;
 696
 697                dev->hard_header_len = sizeof(struct hdlc_header);
 698                dev->header_ops = &ppp_header_ops;
 699                dev->type = ARPHRD_PPP;
 700                call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 701                netif_dormant_on(dev);
 702                return 0;
 703        }
 704
 705        return -EINVAL;
 706}
 707
 708static int __init hdlc_ppp_init(void)
 709{
 710        skb_queue_head_init(&tx_queue);
 711        register_hdlc_protocol(&proto);
 712        return 0;
 713}
 714
 715static void __exit hdlc_ppp_exit(void)
 716{
 717        unregister_hdlc_protocol(&proto);
 718}
 719
 720module_init(hdlc_ppp_init);
 721module_exit(hdlc_ppp_exit);
 722
 723MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 724MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
 725MODULE_LICENSE("GPL v2");
 726