net/ipv4/ipconfig.c

   1 /*
   2  *  $Id: ipconfig.c,v 1.20 1999/03/28 10:18:28 davem Exp $
   3  *
   4  *  Automatic Configuration of IP -- use BOOTP or RARP or user-supplied
   5  *  information to configure own IP address and routes.
   6  *
   7  *  Copyright (C) 1996--1998 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
   8  *
   9  *  Derived from network configuration code in fs/nfs/nfsroot.c,
  10  *  originally Copyright (C) 1995, 1996 Gero Kuhlmann and me.
  11  *
  12  *  BOOTP rewritten to construct and analyse packets itself instead
  13  *  of misusing the IP layer. num_bugs_causing_wrong_arp_replies--;
  14  *                                           -- MJ, December 1998
  15  */
  16
  17 #include <linux/config.h>
  18 #include <linux/types.h>
  19 #include <linux/string.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/random.h>
  23 #include <linux/init.h>
  24 #include <linux/utsname.h>
  25 #include <linux/in.h>
  26 #include <linux/if.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/skbuff.h>
  31 #include <linux/ip.h>
  32 #include <linux/socket.h>
  33 #include <linux/route.h>
  34 #include <linux/udp.h>
  35 #include <net/arp.h>
  36 #include <net/ip.h>
  37 #include <net/ipconfig.h>
  38
  39 #include <asm/segment.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/checksum.h>
  42
  43 /* Define this to allow debugging output */
  44 #undef IPCONFIG_DEBUG
  45
  46 #ifdef IPCONFIG_DEBUG
  47 #define DBG(x) printk x
  48 #else
  49 #define DBG(x) do { } while(0)
  50 #endif
  51
  52 /* Define the timeout for waiting for a RARP/BOOTP reply */
  53 #define CONF_BASE_TIMEOUT       (HZ*5)  /* Initial timeout: 5 seconds */
  54 #define CONF_RETRIES            10      /* 10 retries */
  55 #define CONF_TIMEOUT_RANDOM     (HZ)    /* Maximum amount of randomization */
  56 #define CONF_TIMEOUT_MULT       *5/4    /* Rate of timeout growth */
  57 #define CONF_TIMEOUT_MAX        (HZ*30) /* Maximum allowed timeout */
  58
  59 /* IP configuration */
  60 static char user_dev_name[IFNAMSIZ] __initdata = { 0, };/* Name of user-selected boot device */
  61 u32 ic_myaddr __initdata = INADDR_NONE;         /* My IP address */
  62 u32 ic_servaddr __initdata = INADDR_NONE;       /* Server IP address */
  63 u32 ic_gateway __initdata = INADDR_NONE;        /* Gateway IP address */
  64 u32 ic_netmask __initdata = INADDR_NONE;        /* Netmask for local subnet */
  65 int ic_enable __initdata = 1;                   /* Automatic IP configuration enabled */
  66 int ic_host_name_set __initdata = 0;            /* Host name configured manually */
  67 int ic_set_manually __initdata = 0;             /* IPconfig parameters set manually */
  68
  69 u32 root_server_addr __initdata = INADDR_NONE;          /* Address of boot server */
  70 u8 root_server_path[256] __initdata = { 0, };           /* Path to mount as root */
  71
  72 #if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_RARP)
  73
  74 #define CONFIG_IP_PNP_DYNAMIC
  75
  76 static int ic_proto_enabled __initdata = 0                      /* Protocols enabled */
  77 #ifdef CONFIG_IP_PNP_BOOTP
  78                         | IC_BOOTP
  79 #endif
  80 #ifdef CONFIG_IP_PNP_RARP
  81                         | IC_RARP
  82 #endif
  83                         ;
  84 static int ic_got_reply __initdata = 0;                         /* Protocol(s) we got reply from */
  85
  86 #else
  87
  88 static int ic_proto_enabled __initdata = 0;
  89
  90 #endif
  91
  92 static int ic_proto_have_if __initdata = 0;
  93
  94 /*
  95  *      Network devices
  96  */
  97
  98 struct ic_device {
  99         struct ic_device *next;
 100         struct device *dev;
 101         unsigned short flags;
 102         int able;
 103 };
 104
 105 static struct ic_device *ic_first_dev __initdata = NULL;/* List of open device */
 106 static struct device *ic_dev __initdata = NULL;         /* Selected device */
 107
 108 static int __init ic_open_devs(void)
 109 {
 110         struct ic_device *d, **last;
 111         struct device *dev;
 112         unsigned short oflags;
 113
 114         last = &ic_first_dev;
 115         read_lock_bh(&dev_base_lock);
 116         for (dev = dev_base; dev; dev = dev->next) {
 117                 if (user_dev_name[0] ? !strcmp(dev->name, user_dev_name) :
 118                     (!(dev->flags & IFF_LOOPBACK) &&
 119                      (dev->flags & (IFF_POINTOPOINT|IFF_BROADCAST)) &&
 120                      strncmp(dev->name, "dummy", 5))) {
 121                         int able = 0;
 122                         if (dev->mtu >= 364)
 123                                 able |= IC_BOOTP;
 124                         else
 125                                 printk(KERN_WARNING "BOOTP: Ignoring device %s, MTU %d too small", dev->name, dev->mtu);
 126                         if (!(dev->flags & IFF_NOARP))
 127                                 able |= IC_RARP;
 128                         able &= ic_proto_enabled;
 129                         if (ic_proto_enabled && !able)
 130                                 continue;
 131                         oflags = dev->flags;
 132                         if (dev_change_flags(dev, oflags | IFF_UP) < 0) {
 133                                 printk(KERN_ERR "IP-Config: Failed to open %s\n", dev->name);
 134                                 continue;
 135                         }
 136                         if (!(d = kmalloc(sizeof(struct ic_device), GFP_KERNEL)))
 137                                 return -1;
 138                         d->dev = dev;
 139                         *last = d;
 140                         last = &d->next;
 141                         d->flags = oflags;
 142                         d->able = able;
 143                         ic_proto_have_if |= able;
 144                         DBG(("IP-Config: Opened %s (able=%d)\n", dev->name, able));
 145                 }
 146         }
 147         read_unlock_bh(&dev_base_lock);
 148
 149         *last = NULL;
 150
 151         if (!ic_first_dev) {
 152                 if (user_dev_name[0])
 153                         printk(KERN_ERR "IP-Config: Device `%s' not found.\n", user_dev_name);
 154                 else
 155                         printk(KERN_ERR "IP-Config: No network devices available.\n");
 156                 return -1;
 157         }
 158         return 0;
 159 }
 160
 161 static void __init ic_close_devs(void)
 162 {
 163         struct ic_device *d, *next;
 164         struct device *dev;
 165
 166         next = ic_first_dev;
 167         while ((d = next)) {
 168                 next = d->next;
 169                 dev = d->dev;
 170                 if (dev != ic_dev) {
 171                         DBG(("IP-Config: Downing %s\n", dev->name));
 172                         dev_change_flags(dev, d->flags);
 173                 }
 174                 kfree_s(d, sizeof(struct ic_device));
 175         }
 176 }
 177
 178 /*
 179  *      Interface to various network functions.
 180  */
 181
 182 static inline void
 183 set_sockaddr(struct sockaddr_in *sin, u32 addr, u16 port)
 184 {
 185         sin->sin_family = AF_INET;
 186         sin->sin_addr.s_addr = addr;
 187         sin->sin_port = port;
 188 }
 189
 190 static int __init ic_dev_ioctl(unsigned int cmd, struct ifreq *arg)
 191 {
 192         int res;
 193
 194         mm_segment_t oldfs = get_fs();
 195         set_fs(get_ds());
 196         res = devinet_ioctl(cmd, arg);
 197         set_fs(oldfs);
 198         return res;
 199 }
 200
 201 static int __init ic_route_ioctl(unsigned int cmd, struct rtentry *arg)
 202 {
 203         int res;
 204
 205         mm_segment_t oldfs = get_fs();
 206         set_fs(get_ds());
 207         res = ip_rt_ioctl(cmd, arg);
 208         set_fs(oldfs);
 209         return res;
 210 }
 211
 212 /*
 213  *      Set up interface addresses and routes.
 214  */
 215
 216 static int __init ic_setup_if(void)
 217 {
 218         struct ifreq ir;
 219         struct sockaddr_in *sin = (void *) &ir.ifr_ifru.ifru_addr;
 220         int err;
 221
 222         memset(&ir, 0, sizeof(ir));
 223         strcpy(ir.ifr_ifrn.ifrn_name, ic_dev->name);
 224         set_sockaddr(sin, ic_myaddr, 0);
 225         if ((err = ic_dev_ioctl(SIOCSIFADDR, &ir)) < 0) {
 226                 printk(KERN_ERR "IP-Config: Unable to set interface address (%d).\n", err);
 227                 return -1;
 228         }
 229         set_sockaddr(sin, ic_netmask, 0);
 230         if ((err = ic_dev_ioctl(SIOCSIFNETMASK, &ir)) < 0) {
 231                 printk(KERN_ERR "IP-Config: Unable to set interface netmask (%d).\n", err);
 232                 return -1;
 233         }
 234         set_sockaddr(sin, ic_myaddr | ~ic_netmask, 0);
 235         if ((err = ic_dev_ioctl(SIOCSIFBRDADDR, &ir)) < 0) {
 236                 printk(KERN_ERR "IP-Config: Unable to set interface broadcast address (%d).\n", err);
 237                 return -1;
 238         }
 239         return 0;
 240 }
 241
 242 static int __init ic_setup_routes(void)
 243 {
 244         /* No need to setup device routes, only the default route... */
 245
 246         if (ic_gateway != INADDR_NONE) {
 247                 struct rtentry rm;
 248                 int err;
 249
 250                 memset(&rm, 0, sizeof(rm));
 251                 if ((ic_gateway ^ ic_myaddr) & ic_netmask) {
 252                         printk(KERN_ERR "IP-Config: Gateway not on directly connected network.\n");
 253                         return -1;
 254                 }
 255                 set_sockaddr((struct sockaddr_in *) &rm.rt_dst, 0, 0);
 256                 set_sockaddr((struct sockaddr_in *) &rm.rt_genmask, 0, 0);
 257                 set_sockaddr((struct sockaddr_in *) &rm.rt_gateway, ic_gateway, 0);
 258                 rm.rt_flags = RTF_UP | RTF_GATEWAY;
 259                 if ((err = ic_route_ioctl(SIOCADDRT, &rm)) < 0) {
 260                         printk(KERN_ERR "IP-Config: Cannot add default route (%d).\n", err);
 261                         return -1;
 262                 }
 263         }
 264
 265         return 0;
 266 }
 267
 268 /*
 269  *      Fill in default values for all missing parameters.
 270  */
 271
 272 static int __init ic_defaults(void)
 273 {
 274         /*
 275          *      At this point we have no userspace running so need not
 276          *      claim locks on system_utsname
 277          */
 278
 279         if (!ic_host_name_set)
 280                 strcpy(system_utsname.nodename, in_ntoa(ic_myaddr));
 281
 282         if (root_server_addr == INADDR_NONE)
 283                 root_server_addr = ic_servaddr;
 284
 285         if (ic_netmask == INADDR_NONE) {
 286                 if (IN_CLASSA(ntohl(ic_myaddr)))
 287                         ic_netmask = htonl(IN_CLASSA_NET);
 288                 else if (IN_CLASSB(ntohl(ic_myaddr)))
 289                         ic_netmask = htonl(IN_CLASSB_NET);
 290                 else if (IN_CLASSC(ntohl(ic_myaddr)))
 291                         ic_netmask = htonl(IN_CLASSC_NET);
 292                 else {
 293                         printk(KERN_ERR "IP-Config: Unable to guess netmask for address %08x\n", ic_myaddr);
 294                         return -1;
 295                 }
 296                 printk("IP-Config: Guessing netmask %s\n", in_ntoa(ic_netmask));
 297         }
 298
 299         return 0;
 300 }
 301
 302 /*
 303  *      RARP support.
 304  */
 305
 306 #ifdef CONFIG_IP_PNP_RARP
 307
 308 static int ic_rarp_recv(struct sk_buff *skb, struct device *dev, struct packet_type *pt);
 309
 310 static struct packet_type rarp_packet_type __initdata = {
 311         __constant_htons(ETH_P_RARP),
 312         NULL,                   /* Listen to all devices */
 313         ic_rarp_recv,
 314         NULL,
 315         NULL
 316 };
 317
 318 static inline void ic_rarp_init(void)
 319 {
 320         dev_add_pack(&rarp_packet_type);
 321 }
 322
 323 static inline void ic_rarp_cleanup(void)
 324 {
 325         dev_remove_pack(&rarp_packet_type);
 326 }
 327
 328 /*
 329  *  Process received RARP packet.
 330  */
 331 static int __init
 332 ic_rarp_recv(struct sk_buff *skb, struct device *dev, struct packet_type *pt)
 333 {
 334         struct arphdr *rarp = (struct arphdr *)skb->h.raw;
 335         unsigned char *rarp_ptr = (unsigned char *) (rarp + 1);
 336         unsigned long sip, tip;
 337         unsigned char *sha, *tha;               /* s for "source", t for "target" */
 338
 339         /* If we already have a reply, just drop the packet */
 340         if (ic_got_reply)
 341                 goto drop;
 342
 343         /* If this test doesn't pass, it's not IP, or we should ignore it anyway */
 344         if (rarp->ar_hln != dev->addr_len || dev->type != ntohs(rarp->ar_hrd))
 345                 goto drop;
 346
 347         /* If it's not a RARP reply, delete it. */
 348         if (rarp->ar_op != htons(ARPOP_RREPLY))
 349                 goto drop;
 350
 351         /* If it's not Ethernet, delete it. */
 352         if (rarp->ar_pro != htons(ETH_P_IP))
 353                 goto drop;
 354
 355         /* Extract variable-width fields */
 356         sha = rarp_ptr;
 357         rarp_ptr += dev->addr_len;
 358         memcpy(&sip, rarp_ptr, 4);
 359         rarp_ptr += 4;
 360         tha = rarp_ptr;
 361         rarp_ptr += dev->addr_len;
 362         memcpy(&tip, rarp_ptr, 4);
 363
 364         /* Discard packets which are not meant for us. */
 365         if (memcmp(tha, dev->dev_addr, dev->addr_len))
 366                 goto drop;
 367
 368         /* Discard packets which are not from specified server. */
 369         if (ic_servaddr != INADDR_NONE && ic_servaddr != sip)
 370                 goto drop;
 371
 372         /* Victory! The packet is what we were looking for! */
 373         if (!ic_got_reply) {
 374                 ic_got_reply = IC_RARP;
 375                 ic_dev = dev;
 376                 if (ic_myaddr == INADDR_NONE)
 377                         ic_myaddr = tip;
 378                 ic_servaddr = sip;
 379         }
 380
 381         /* And throw the packet out... */
 382 drop:
 383         kfree_skb(skb);
 384         return 0;
 385 }
 386
 387
 388 /*
 389  *  Send RARP request packet over all devices which allow RARP.
 390  */
 391 static void __init ic_rarp_send(void)
 392 {
 393         struct ic_device *d;
 394
 395         for (d=ic_first_dev; d; d=d->next)
 396                 if (d->able & IC_RARP) {
 397                         struct device *dev = d->dev;
 398                         arp_send(ARPOP_RREQUEST, ETH_P_RARP, 0, dev, 0, NULL,
 399                                  dev->dev_addr, dev->dev_addr);
 400                 }
 401 }
 402
 403 #endif
 404
 405 /*
 406  *      BOOTP support.
 407  */
 408
 409 #ifdef CONFIG_IP_PNP_BOOTP
 410
 411 struct bootp_pkt {              /* BOOTP packet format */
 412         struct iphdr iph;       /* IP header */
 413         struct udphdr udph;     /* UDP header */
 414         u8 op;                  /* 1=request, 2=reply */
 415         u8 htype;               /* HW address type */
 416         u8 hlen;                /* HW address length */
 417         u8 hops;                /* Used only by gateways */
 418         u32 xid;                /* Transaction ID */
 419         u16 secs;               /* Seconds since we started */
 420         u16 flags;              /* Just what it says */
 421         u32 client_ip;          /* Client's IP address if known */
 422         u32 your_ip;            /* Assigned IP address */
 423         u32 server_ip;          /* Server's IP address */
 424         u32 relay_ip;           /* IP address of BOOTP relay */
 425         u8 hw_addr[16];         /* Client's HW address */
 426         u8 serv_name[64];       /* Server host name */
 427         u8 boot_file[128];      /* Name of boot file */
 428         u8 vendor_area[128];    /* Area for extensions */
 429 };
 430
 431 #define BOOTP_REQUEST 1
 432 #define BOOTP_REPLY 2
 433
 434 static u32 ic_bootp_xid;
 435
 436 static int ic_bootp_recv(struct sk_buff *skb, struct device *dev, struct packet_type *pt);
 437
 438 static struct packet_type bootp_packet_type __initdata = {
 439         __constant_htons(ETH_P_IP),
 440         NULL,                   /* Listen to all devices */
 441         ic_bootp_recv,
 442         NULL,
 443         NULL
 444 };
 445
 446
 447 /*
 448  *  Initialize BOOTP extension fields in the request.
 449  */
 450 static void __init ic_bootp_init_ext(u8 *e)
 451 {
 452         *e++ = 99;              /* RFC1048 Magic Cookie */
 453         *e++ = 130;
 454         *e++ = 83;
 455         *e++ = 99;
 456         *e++ = 1;               /* Subnet mask request */
 457         *e++ = 4;
 458         e += 4;
 459         *e++ = 3;               /* Default gateway request */
 460         *e++ = 4;
 461         e += 4;
 462         *e++ = 12;              /* Host name request */
 463         *e++ = 32;
 464         e += 32;
 465         *e++ = 40;              /* NIS Domain name request */
 466         *e++ = 32;
 467         e += 32;
 468         *e++ = 17;              /* Boot path */
 469         *e++ = 32;
 470         e += 32;
 471         *e = 255;               /* End of the list */
 472 }
 473
 474
 475 /*
 476  *  Initialize the BOOTP mechanism.
 477  */
 478 static inline void ic_bootp_init(void)
 479 {
 480         get_random_bytes(&ic_bootp_xid, sizeof(u32));
 481         DBG(("BOOTP: XID=%08x\n", ic_bootp_xid));
 482         dev_add_pack(&bootp_packet_type);
 483 }
 484
 485
 486 /*
 487  *  BOOTP cleanup.
 488  */
 489 static inline void ic_bootp_cleanup(void)
 490 {
 491         dev_remove_pack(&bootp_packet_type);
 492 }
 493
 494
 495 /*
 496  *  Send BOOTP request to single interface.
 497  */
 498 static void __init ic_bootp_send_if(struct ic_device *d, u32 jiffies)
 499 {
 500         struct device *dev = d->dev;
 501         struct sk_buff *skb;
 502         struct bootp_pkt *b;
 503         int hh_len = (dev->hard_header_len + 15) & ~15;
 504         struct iphdr *h;
 505
 506         /* Allocate packet */
 507         skb = alloc_skb(sizeof(struct bootp_pkt) + hh_len + 15, GFP_KERNEL);
 508         if (!skb)
 509                 return;
 510         skb_reserve(skb, hh_len);
 511         b = (struct bootp_pkt *) skb_put(skb, sizeof(struct bootp_pkt));
 512         memset(b, 0, sizeof(struct bootp_pkt));
 513
 514         /* Construct IP header */
 515         skb->nh.iph = h = &b->iph;
 516         h->version = 4;
 517         h->ihl = 5;
 518         h->tot_len = htons(sizeof(struct bootp_pkt));
 519         h->frag_off = htons(IP_DF);
 520         h->ttl = 64;
 521         h->protocol = IPPROTO_UDP;
 522         h->daddr = INADDR_BROADCAST;
 523         h->check = ip_fast_csum((unsigned char *) h, h->ihl);
 524
 525         /* Construct UDP header */
 526         b->udph.source = htons(68);
 527         b->udph.dest = htons(67);
 528         b->udph.len = htons(sizeof(struct bootp_pkt) - sizeof(struct iphdr));
 529         /* UDP checksum not calculated -- explicitly allowed in BOOTP RFC */
 530
 531         /* Construct BOOTP header */
 532         b->op = BOOTP_REQUEST;
 533         b->htype = dev->type;
 534         b->hlen = dev->addr_len;
 535         memcpy(b->hw_addr, dev->dev_addr, dev->addr_len);
 536         b->secs = htons(jiffies / HZ);
 537         b->xid = ic_bootp_xid;
 538         ic_bootp_init_ext(b->vendor_area);
 539
 540         /* Chain packet down the line... */
 541         skb->dev = dev;
 542         skb->protocol = __constant_htons(ETH_P_IP);
 543         if ((dev->hard_header &&
 544              dev->hard_header(skb, dev, ntohs(skb->protocol), dev->broadcast, dev->dev_addr, skb->len) < 0) ||
 545             dev_queue_xmit(skb) < 0)
 546                 printk("E");
 547 }
 548
 549
 550 /*
 551  *  Send BOOTP requests to all interfaces.
 552  */
 553 static void __init ic_bootp_send(u32 jiffies)
 554 {
 555         struct ic_device *d;
 556
 557         for(d=ic_first_dev; d; d=d->next)
 558                 if (d->able & IC_BOOTP)
 559                         ic_bootp_send_if(d, jiffies);
 560 }
 561
 562
 563 /*
 564  *  Copy BOOTP-supplied string if not already set.
 565  */
 566 static int __init ic_bootp_string(char *dest, char *src, int len, int max)
 567 {
 568         if (!len)
 569                 return 0;
 570         if (len > max-1)
 571                 len = max-1;
 572         strncpy(dest, src, len);
 573         dest[len] = '\0';
 574         return 1;
 575 }
 576
 577
 578 /*
 579  *  Process BOOTP extension.
 580  */
 581 static void __init ic_do_bootp_ext(u8 *ext)
 582 {
 583 #ifdef IPCONFIG_DEBUG
 584         u8 *c;
 585
 586         printk("BOOTP: Got extension %02x",*ext);
 587         for(c=ext+2; c<ext+2+ext[1]; c++)
 588                 printk(" %02x", *c);
 589         printk("\n");
 590 #endif
 591
 592         switch (*ext++) {
 593                 case 1:         /* Subnet mask */
 594                         if (ic_netmask == INADDR_NONE)
 595                                 memcpy(&ic_netmask, ext+1, 4);
 596                         break;
 597                 case 3:         /* Default gateway */
 598                         if (ic_gateway == INADDR_NONE)
 599                                 memcpy(&ic_gateway, ext+1, 4);
 600                         break;
 601                 case 12:        /* Host name */
 602                         ic_bootp_string(system_utsname.nodename, ext+1, *ext, __NEW_UTS_LEN);
 603                         ic_host_name_set = 1;
 604                         break;
 605                 case 40:        /* NIS Domain name */
 606                         ic_bootp_string(system_utsname.domainname, ext+1, *ext, __NEW_UTS_LEN);
 607                         break;
 608                 case 17:        /* Root path */
 609                         if (!root_server_path[0])
 610                                 ic_bootp_string(root_server_path, ext+1, *ext, sizeof(root_server_path));
 611                         break;
 612         }
 613 }
 614
 615
 616 /*
 617  *  Receive BOOTP reply.
 618  */
 619 static int __init ic_bootp_recv(struct sk_buff *skb, struct device *dev, struct packet_type *pt)
 620 {
 621         struct bootp_pkt *b = (struct bootp_pkt *) skb->nh.iph;
 622         struct iphdr *h = &b->iph;
 623         int len;
 624
 625         /* If we already have a reply, just drop the packet */
 626         if (ic_got_reply)
 627                 goto drop;
 628
 629         /* Check whether it's a BOOTP packet */
 630         if (skb->pkt_type == PACKET_OTHERHOST ||
 631             skb->len < sizeof(struct udphdr) + sizeof(struct iphdr) ||
 632             h->ihl != 5 ||
 633             h->version != 4 ||
 634             ip_fast_csum((char *) h, h->ihl) != 0 ||
 635             skb->len < ntohs(h->tot_len) ||
 636             h->protocol != IPPROTO_UDP ||
 637             b->udph.source != htons(67) ||
 638             b->udph.dest != htons(68) ||
 639             ntohs(h->tot_len) < ntohs(b->udph.len) + sizeof(struct iphdr))
 640                 goto drop;
 641
 642         /* Fragments are not supported */
 643         if (h->frag_off & htons(IP_OFFSET|IP_MF)) {
 644                 printk(KERN_ERR "BOOTP: Ignoring fragmented reply.\n");
 645                 goto drop;
 646         }
 647
 648         /* Is it a reply to our BOOTP request? */
 649         len = ntohs(b->udph.len) - sizeof(struct udphdr);
 650         if (len < 300 ||                                    /* See RFC 951:2.1 */
 651             b->op != BOOTP_REPLY ||
 652             b->xid != ic_bootp_xid) {
 653                 printk("?");
 654                 goto drop;
 655         }
 656
 657         /* Extract basic fields */
 658         ic_myaddr = b->your_ip;
 659         ic_servaddr = b->server_ip;
 660         ic_got_reply = IC_BOOTP;
 661         ic_dev = dev;
 662
 663         /* Parse extensions */
 664         if (b->vendor_area[0] == 99 &&  /* Check magic cookie */
 665             b->vendor_area[1] == 130 &&
 666             b->vendor_area[2] == 83 &&
 667             b->vendor_area[3] == 99) {
 668                 u8 *ext = &b->vendor_area[4];
 669                 u8 *end = (u8 *) b + len;
 670                 while (ext < end && *ext != 0xff) {
 671                         if (*ext == 0)          /* Padding */
 672                                 ext++;
 673                         else {
 674                                 u8 *opt = ext;
 675                                 ext += ext[1] + 2;
 676                                 if (ext <= end)
 677                                         ic_do_bootp_ext(opt);
 678                         }
 679                 }
 680         }
 681
 682         if (ic_gateway == INADDR_NONE && b->relay_ip)
 683                 ic_gateway = b->relay_ip;
 684
 685 drop:
 686         kfree_skb(skb);
 687         return 0;
 688 }
 689
 690
 691 #endif
 692
 693
 694 /*
 695  *      Dynamic IP configuration -- BOOTP and RARP.
 696  */
 697
 698 #ifdef CONFIG_IP_PNP_DYNAMIC
 699
 700 static int __init ic_dynamic(void)
 701 {
 702         int retries;
 703         unsigned long timeout, jiff;
 704         unsigned long start_jiffies;
 705         int do_rarp = ic_proto_have_if & IC_RARP;
 706         int do_bootp = ic_proto_have_if & IC_BOOTP;
 707
 708         /*
 709          * If neither BOOTP nor RARP was selected, return with an error. This
 710          * routine gets only called when some pieces of information are mis-
 711          * sing, and without BOOTP and RARP we are not able to get that in-
 712          * formation.
 713          */
 714         if (!ic_proto_enabled) {
 715                 printk(KERN_ERR "IP-Config: Incomplete network configuration information.\n");
 716                 return -1;
 717         }
 718
 719 #ifdef CONFIG_IP_PNP_BOOTP
 720         if ((ic_proto_enabled ^ ic_proto_have_if) & IC_BOOTP)
 721                 printk(KERN_ERR "BOOTP: No suitable device found.\n");
 722 #endif
 723
 724 #ifdef CONFIG_IP_PNP_RARP
 725         if ((ic_proto_enabled ^ ic_proto_have_if) & IC_RARP)
 726                 printk(KERN_ERR "RARP: No suitable device found.\n");
 727 #endif
 728
 729         if (!ic_proto_have_if)
 730                 /* Error message already printed */
 731                 return -1;
 732
 733         /*
 734          * Setup RARP and BOOTP protocols
 735          */
 736 #ifdef CONFIG_IP_PNP_RARP
 737         if (do_rarp)
 738                 ic_rarp_init();
 739 #endif
 740 #ifdef CONFIG_IP_PNP_BOOTP
 741         if (do_bootp)
 742                 ic_bootp_init();
 743 #endif
 744
 745         /*
 746          * Send requests and wait, until we get an answer. This loop
 747          * seems to be a terrible waste of CPU time, but actually there is
 748          * only one process running at all, so we don't need to use any
 749          * scheduler functions.
 750          * [Actually we could now, but the nothing else running note still
 751          *  applies.. - AC]
 752          */
 753         printk(KERN_NOTICE "Sending %s%s%s requests...",
 754                 do_bootp ? "BOOTP" : "",
 755                 do_bootp && do_rarp ? " and " : "",
 756                 do_rarp ? "RARP" : "");
 757         start_jiffies = jiffies;
 758         retries = CONF_RETRIES;
 759         get_random_bytes(&timeout, sizeof(timeout));
 760         timeout = CONF_BASE_TIMEOUT + (timeout % (unsigned) CONF_TIMEOUT_RANDOM);
 761         for(;;) {
 762 #ifdef CONFIG_IP_PNP_BOOTP
 763                 if (do_bootp)
 764                         ic_bootp_send(jiffies - start_jiffies);
 765 #endif
 766 #ifdef CONFIG_IP_PNP_RARP
 767                 if (do_rarp)
 768                         ic_rarp_send();
 769 #endif
 770                 printk(".");
 771                 jiff = jiffies + timeout;
 772                 while (jiffies < jiff && !ic_got_reply)
 773                         ;
 774                 if (ic_got_reply) {
 775                         printk(" OK\n");
 776                         break;
 777                 }
 778                 if (! --retries) {
 779                         printk(" timed out!\n");
 780                         break;
 781                 }
 782                 timeout = timeout CONF_TIMEOUT_MULT;
 783                 if (timeout > CONF_TIMEOUT_MAX)
 784                         timeout = CONF_TIMEOUT_MAX;
 785         }
 786
 787 #ifdef CONFIG_IP_PNP_RARP
 788         if (do_rarp)
 789                 ic_rarp_cleanup();
 790 #endif
 791 #ifdef CONFIG_IP_PNP_BOOTP
 792         if (do_bootp)
 793                 ic_bootp_cleanup();
 794 #endif
 795
 796         if (!ic_got_reply)
 797                 return -1;
 798
 799         printk("IP-Config: Got %s answer from %s, ",
 800                 (ic_got_reply & IC_BOOTP) ? "BOOTP" : "RARP",
 801                 in_ntoa(ic_servaddr));
 802         printk("my address is %s\n", in_ntoa(ic_myaddr));
 803
 804         return 0;
 805 }
 806
 807 #endif
 808
 809 /*
 810  *      IP Autoconfig dispatcher.
 811  */
 812
 813 int __init ip_auto_config(void)
 814 {
 815         if (!ic_enable)
 816                 return 0;
 817
 818         DBG(("IP-Config: Entered.\n"));
 819
 820         /* Setup all network devices */
 821         if (ic_open_devs() < 0)
 822                 return -1;
 823
 824         /*
 825          * If the config information is insufficient (e.g., our IP address or
 826          * IP address of the boot server is missing or we have multiple network
 827          * interfaces and no default was set), use BOOTP or RARP to get the
 828          * missing values.
 829          */
 830         if (ic_myaddr == INADDR_NONE ||
 831 #ifdef CONFIG_ROOT_NFS
 832             (root_server_addr == INADDR_NONE && ic_servaddr == INADDR_NONE) ||
 833 #endif
 834             ic_first_dev->next) {
 835 #ifdef CONFIG_IP_PNP_DYNAMIC
 836                 if (ic_dynamic() < 0) {
 837                         printk(KERN_ERR "IP-Config: Auto-configuration of network failed.\n");
 838                         ic_close_devs();
 839                         return -1;
 840                 }
 841 #else
 842                 printk(KERN_ERR "IP-Config: Incomplete network configuration information.\n");
 843                 ic_close_devs();
 844                 return -1;
 845 #endif
 846         } else {
 847                 ic_dev = ic_first_dev->dev;     /* Device selected manually or only one device -> use it */
 848         }
 849
 850         /*
 851          * Use defaults whereever applicable.
 852          */
 853         if (ic_defaults() < 0)
 854                 return -1;
 855
 856         /*
 857          * Close all network devices except the device we've
 858          * autoconfigured and set up routes.
 859          */
 860         ic_close_devs();
 861         if (ic_setup_if() < 0 || ic_setup_routes() < 0)
 862                 return -1;
 863
 864         DBG(("IP-Config: device=%s, local=%08x, server=%08x, boot=%08x, gw=%08x, mask=%08x\n",
 865             ic_dev->name, ic_myaddr, ic_servaddr, root_server_addr, ic_gateway, ic_netmask));
 866         DBG(("IP-Config: host=%s, domain=%s, path=`%s'\n", system_utsname.nodename,
 867             system_utsname.domainname, root_server_path));
 868         return 0;
 869 }
 870
 871 /*
 872  *  Decode any IP configuration options in the "ip=" or "nfsaddrs=" kernel
 873  *  command line parameter. It consists of option fields separated by colons in
 874  *  the following order:
 875  *
 876  *  <client-ip>:<server-ip>:<gw-ip>:<netmask>:<host name>:<device>:<bootp|rarp>
 877  *
 878  *  Any of the fields can be empty which means to use a default value:
 879  *      <client-ip>     - address given by BOOTP or RARP
 880  *      <server-ip>     - address of host returning BOOTP or RARP packet
 881  *      <gw-ip>         - none, or the address returned by BOOTP
 882  *      <netmask>       - automatically determined from <client-ip>, or the
 883  *                        one returned by BOOTP
 884  *      <host name>     - <client-ip> in ASCII notation, or the name returned
 885  *                        by BOOTP
 886  *      <device>        - use all available devices
 887  *      <bootp|rarp|both|off> - use both protocols to determine my own address
 888  */
 889 static int __init ic_proto_name(char *name)
 890 {
 891         if (!strcmp(name, "off")) {
 892                 ic_proto_enabled = 0;
 893                 return 1;
 894         }
 895 #ifdef CONFIG_IP_PNP_BOOTP
 896         else if (!strcmp(name, "bootp")) {
 897                 ic_proto_enabled &= ~IC_RARP;
 898                 return 1;
 899         }
 900 #endif
 901 #ifdef CONFIG_IP_PNP_RARP
 902         else if (!strcmp(name, "rarp")) {
 903                 ic_proto_enabled &= ~IC_BOOTP;
 904                 return 1;
 905         }
 906 #endif
 907 #ifdef CONFIG_IP_PNP_DYNAMIC
 908         else if (!strcmp(name, "both")) {
 909                 return 1;
 910         }
 911 #endif
 912         return 0;
 913 }
 914
 915 void __init ip_auto_config_setup(char *addrs, int *ints)
 916 {
 917         char *cp, *ip, *dp;
 918         int num = 0;
 919
 920         ic_set_manually = 1;
 921         if (!strcmp(addrs, "off")) {
 922                 ic_enable = 0;
 923                 return;
 924         }
 925         if (ic_proto_name(addrs))
 926                 return;
 927
 928         /* Parse the whole string */
 929         ip = addrs;
 930         while (ip && *ip) {
 931                 if ((cp = strchr(ip, ':')))
 932                         *cp++ = '\0';
 933                 if (strlen(ip) > 0) {
 934                         DBG(("IP-Config: Parameter #%d: `%s'\n", num, ip));
 935                         switch (num) {
 936                         case 0:
 937                                 if ((ic_myaddr = in_aton(ip)) == INADDR_ANY)
 938                                         ic_myaddr = INADDR_NONE;
 939                                 break;
 940                         case 1:
 941                                 if ((ic_servaddr = in_aton(ip)) == INADDR_ANY)
 942                                         ic_servaddr = INADDR_NONE;
 943                                 break;
 944                         case 2:
 945                                 if ((ic_gateway = in_aton(ip)) == INADDR_ANY)
 946                                         ic_gateway = INADDR_NONE;
 947                                 break;
 948                         case 3:
 949                                 if ((ic_netmask = in_aton(ip)) == INADDR_ANY)
 950                                         ic_netmask = INADDR_NONE;
 951                                 break;
 952                         case 4:
 953                                 if ((dp = strchr(ip, '.'))) {
 954                                         *dp++ = '\0';
 955                                         strncpy(system_utsname.domainname, dp, __NEW_UTS_LEN);
 956                                         system_utsname.domainname[__NEW_UTS_LEN] = '\0';
 957                                 }
 958                                 strncpy(system_utsname.nodename, ip, __NEW_UTS_LEN);
 959                                 system_utsname.nodename[__NEW_UTS_LEN] = '\0';
 960                                 ic_host_name_set = 1;
 961                                 break;
 962                         case 5:
 963                                 strncpy(user_dev_name, ip, IFNAMSIZ);
 964                                 user_dev_name[IFNAMSIZ-1] = '\0';
 965                                 break;
 966                         case 6:
 967                                 ic_proto_name(ip);
 968                                 break;
 969                         }
 970                 }
 971                 ip = cp;
 972                 num++;
 973         }
 974 }