lib/libstand/bootp.c

   1 /*      $NetBSD: bootp.c,v 1.14 1998/02/16 11:10:54 drochner Exp $      */
   2
   3 /*
   4  * Copyright (c) 1992 Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This software was developed by the Computer Systems Engineering group
   8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   9  * contributed to Berkeley.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp  (LBL)
  36  */
  37
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <sys/types.h>
  42 #include <netinet/in.h>
  43 #include <netinet/in_systm.h>
  44
  45 #include <string.h>
  46
  47 #define BOOTP_DEBUGxx
  48 #define SUPPORT_DHCP
  49
  50 #include "stand.h"
  51 #include "net.h"
  52 #include "netif.h"
  53 #include "bootp.h"
  54
  55
  56 struct in_addr servip;
  57
  58 static n_long   nmask, smask;
  59
  60 static time_t   bot;
  61
  62 static  char vm_rfc1048[4] = VM_RFC1048;
  63 #ifdef BOOTP_VEND_CMU
  64 static  char vm_cmu[4] = VM_CMU;
  65 #endif
  66
  67 /* Local forwards */
  68 static  ssize_t bootpsend(struct iodesc *, void *, size_t);
  69 static  ssize_t bootprecv(struct iodesc *, void *, size_t, time_t);
  70 static  int vend_rfc1048(u_char *, u_int);
  71 #ifdef BOOTP_VEND_CMU
  72 static  void vend_cmu(u_char *);
  73 #endif
  74
  75 #ifdef SUPPORT_DHCP
  76 static char expected_dhcpmsgtype = -1, dhcp_ok;
  77 struct in_addr dhcp_serverip;
  78 #endif
  79
  80 /* Fetch required bootp infomation */
  81 void
  82 bootp(sock, flag)
  83         int sock;
  84         int flag;
  85 {
  86         struct iodesc *d;
  87         struct bootp *bp;
  88         struct {
  89                 u_char header[HEADER_SIZE];
  90                 struct bootp wbootp;
  91         } wbuf;
  92         struct {
  93                 u_char header[HEADER_SIZE];
  94                 struct bootp rbootp;
  95         } rbuf;
  96
  97 #ifdef BOOTP_DEBUG
  98         if (debug)
  99                 printf("bootp: socket=%d\n", sock);
 100 #endif
 101         if (!bot)
 102                 bot = getsecs();
 103
 104         if (!(d = socktodesc(sock))) {
 105                 printf("bootp: bad socket. %d\n", sock);
 106                 return;
 107         }
 108 #ifdef BOOTP_DEBUG
 109         if (debug)
 110                 printf("bootp: d=%lx\n", (long)d);
 111 #endif
 112
 113         bp = &wbuf.wbootp;
 114         bzero(bp, sizeof(*bp));
 115
 116         bp->bp_op = BOOTREQUEST;
 117         bp->bp_htype = 1;               /* 10Mb Ethernet (48 bits) */
 118         bp->bp_hlen = 6;
 119         bp->bp_xid = htonl(d->xid);
 120         MACPY(d->myea, bp->bp_chaddr);
 121         strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file));
 122         bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
 123 #ifdef SUPPORT_DHCP
 124         bp->bp_vend[4] = TAG_DHCP_MSGTYPE;
 125         bp->bp_vend[5] = 1;
 126         bp->bp_vend[6] = DHCPDISCOVER;
 127
 128         /*
 129          * If we are booting from PXE, we want to send the string
 130          * 'PXEClient' to the DHCP server so you have the option of
 131          * only responding to PXE aware dhcp requests.
 132          */
 133         if (flag & BOOTP_PXE) {
 134                 bp->bp_vend[7] = TAG_CLASSID;
 135                 bp->bp_vend[8] = 9;
 136                 bcopy("PXEClient", &bp->bp_vend[9], 9);
 137                 bp->bp_vend[18] = TAG_END;
 138         } else
 139                 bp->bp_vend[7] = TAG_END;
 140 #else
 141         bp->bp_vend[4] = TAG_END;
 142 #endif
 143
 144         d->myip.s_addr = INADDR_ANY;
 145         d->myport = htons(IPPORT_BOOTPC);
 146         d->destip.s_addr = INADDR_BROADCAST;
 147         d->destport = htons(IPPORT_BOOTPS);
 148
 149 #ifdef SUPPORT_DHCP
 150         expected_dhcpmsgtype = DHCPOFFER;
 151         dhcp_ok = 0;
 152 #endif
 153
 154         if(sendrecv(d,
 155                     bootpsend, bp, sizeof(*bp),
 156                     bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
 157            == -1) {
 158             printf("bootp: no reply\n");
 159             return;
 160         }
 161
 162 #ifdef SUPPORT_DHCP
 163         if(dhcp_ok) {
 164                 u_int32_t leasetime;
 165                 bp->bp_vend[6] = DHCPREQUEST;
 166                 bp->bp_vend[7] = TAG_REQ_ADDR;
 167                 bp->bp_vend[8] = 4;
 168                 bcopy(&rbuf.rbootp.bp_yiaddr, &bp->bp_vend[9], 4);
 169                 bp->bp_vend[13] = TAG_SERVERID;
 170                 bp->bp_vend[14] = 4;
 171                 bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4);
 172                 bp->bp_vend[19] = TAG_LEASETIME;
 173                 bp->bp_vend[20] = 4;
 174                 leasetime = htonl(300);
 175                 bcopy(&leasetime, &bp->bp_vend[21], 4);
 176                 if (flag & BOOTP_PXE) {
 177                         bp->bp_vend[25] = TAG_CLASSID;
 178                         bp->bp_vend[26] = 9;
 179                         bcopy("PXEClient", &bp->bp_vend[27], 9);
 180                         bp->bp_vend[36] = TAG_END;
 181                 } else
 182                         bp->bp_vend[25] = TAG_END;
 183
 184                 expected_dhcpmsgtype = DHCPACK;
 185
 186                 if(sendrecv(d,
 187                             bootpsend, bp, sizeof(*bp),
 188                             bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
 189                    == -1) {
 190                         printf("DHCPREQUEST failed\n");
 191                         return;
 192                 }
 193         }
 194 #endif
 195
 196         myip = d->myip = rbuf.rbootp.bp_yiaddr;
 197         servip = rbuf.rbootp.bp_siaddr;
 198         if(rootip.s_addr == INADDR_ANY) rootip = servip;
 199         bcopy(rbuf.rbootp.bp_file, bootfile, sizeof(bootfile));
 200         bootfile[sizeof(bootfile) - 1] = '\0';
 201
 202         if (IN_CLASSA(ntohl(myip.s_addr)))
 203                 nmask = htonl(IN_CLASSA_NET);
 204         else if (IN_CLASSB(ntohl(myip.s_addr)))
 205                 nmask = htonl(IN_CLASSB_NET);
 206         else
 207                 nmask = htonl(IN_CLASSC_NET);
 208 #ifdef BOOTP_DEBUG
 209         if (debug)
 210                 printf("'native netmask' is %s\n", intoa(nmask));
 211 #endif
 212
 213         /* Check subnet mask against net mask; toss if bogus */
 214         if ((nmask & smask) != nmask) {
 215 #ifdef BOOTP_DEBUG
 216                 if (debug)
 217                         printf("subnet mask (%s) bad\n", intoa(smask));
 218 #endif
 219                 smask = 0;
 220         }
 221
 222         /* Get subnet (or natural net) mask */
 223         netmask = nmask;
 224         if (smask)
 225                 netmask = smask;
 226 #ifdef BOOTP_DEBUG
 227         if (debug)
 228                 printf("mask: %s\n", intoa(netmask));
 229 #endif
 230
 231         /* We need a gateway if root is on a different net */
 232         if (!SAMENET(myip, rootip, netmask)) {
 233 #ifdef BOOTP_DEBUG
 234                 if (debug)
 235                         printf("need gateway for root ip\n");
 236 #endif
 237         }
 238
 239         /* Toss gateway if on a different net */
 240         if (!SAMENET(myip, gateip, netmask)) {
 241 #ifdef BOOTP_DEBUG
 242                 if (debug)
 243                         printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
 244 #endif
 245                 gateip.s_addr = 0;
 246         }
 247
 248         /* Bump xid so next request will be unique. */
 249         ++d->xid;
 250 }
 251
 252 /* Transmit a bootp request */
 253 static ssize_t
 254 bootpsend(d, pkt, len)
 255         struct iodesc *d;
 256         void *pkt;
 257         size_t len;
 258 {
 259         struct bootp *bp;
 260
 261 #ifdef BOOTP_DEBUG
 262         if (debug)
 263                 printf("bootpsend: d=%lx called.\n", (long)d);
 264 #endif
 265
 266         bp = pkt;
 267         bp->bp_secs = htons((u_short)(getsecs() - bot));
 268
 269 #ifdef BOOTP_DEBUG
 270         if (debug)
 271                 printf("bootpsend: calling sendudp\n");
 272 #endif
 273
 274         return (sendudp(d, pkt, len));
 275 }
 276
 277 static ssize_t
 278 bootprecv(d, pkt, len, tleft)
 279 struct iodesc *d;
 280 void *pkt;
 281 size_t len;
 282 time_t tleft;
 283 {
 284         ssize_t n;
 285         struct bootp *bp;
 286
 287 #ifdef BOOTP_DEBUGx
 288         if (debug)
 289                 printf("bootp_recvoffer: called\n");
 290 #endif
 291
 292         n = readudp(d, pkt, len, tleft);
 293         if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE)
 294                 goto bad;
 295
 296         bp = (struct bootp *)pkt;
 297
 298 #ifdef BOOTP_DEBUG
 299         if (debug)
 300                 printf("bootprecv: checked.  bp = 0x%lx, n = %d\n",
 301                     (long)bp, (int)n);
 302 #endif
 303         if (bp->bp_xid != htonl(d->xid)) {
 304 #ifdef BOOTP_DEBUG
 305                 if (debug) {
 306                         printf("bootprecv: expected xid 0x%lx, got 0x%x\n",
 307                             d->xid, ntohl(bp->bp_xid));
 308                 }
 309 #endif
 310                 goto bad;
 311         }
 312
 313 #ifdef BOOTP_DEBUG
 314         if (debug)
 315                 printf("bootprecv: got one!\n");
 316 #endif
 317
 318         /* Suck out vendor info */
 319         if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
 320                 if(vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend)) != 0)
 321                     goto bad;
 322         }
 323 #ifdef BOOTP_VEND_CMU
 324         else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
 325                 vend_cmu(bp->bp_vend);
 326 #endif
 327         else
 328                 printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
 329
 330         return(n);
 331 bad:
 332         errno = 0;
 333         return (-1);
 334 }
 335
 336 static int
 337 vend_rfc1048(cp, len)
 338         u_char *cp;
 339         u_int len;
 340 {
 341         u_char *ep;
 342         int size;
 343         u_char tag;
 344
 345 #ifdef BOOTP_DEBUG
 346         if (debug)
 347                 printf("vend_rfc1048 bootp info. len=%d\n", len);
 348 #endif
 349         ep = cp + len;
 350
 351         /* Step over magic cookie */
 352         cp += sizeof(int);
 353
 354         while (cp < ep) {
 355                 tag = *cp++;
 356                 size = *cp++;
 357                 if (tag == TAG_END)
 358                         break;
 359
 360                 if (tag == TAG_SUBNET_MASK) {
 361                         bcopy(cp, &smask, sizeof(smask));
 362                 }
 363                 if (tag == TAG_GATEWAY) {
 364                         bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
 365                 }
 366                 if (tag == TAG_SWAPSERVER) {
 367                         /* let it override bp_siaddr */
 368                         bcopy(cp, &rootip.s_addr, sizeof(swapip.s_addr));
 369                 }
 370                 if (tag == TAG_ROOTPATH) {
 371                         strncpy(rootpath, (char *)cp, sizeof(rootpath));
 372                         rootpath[size] = '\0';
 373                 }
 374                 if (tag == TAG_HOSTNAME) {
 375                         strncpy(hostname, (char *)cp, sizeof(hostname));
 376                         hostname[size] = '\0';
 377                 }
 378 #ifdef SUPPORT_DHCP
 379                 if (tag == TAG_DHCP_MSGTYPE) {
 380                         if(*cp != expected_dhcpmsgtype)
 381                             return(-1);
 382                         dhcp_ok = 1;
 383                 }
 384                 if (tag == TAG_SERVERID) {
 385                         bcopy(cp, &dhcp_serverip.s_addr,
 386                               sizeof(dhcp_serverip.s_addr));
 387                 }
 388 #endif
 389                 cp += size;
 390         }
 391         return(0);
 392 }
 393
 394 #ifdef BOOTP_VEND_CMU
 395 static void
 396 vend_cmu(cp)
 397         u_char *cp;
 398 {
 399         struct cmu_vend *vp;
 400
 401 #ifdef BOOTP_DEBUG
 402         if (debug)
 403                 printf("vend_cmu bootp info.\n");
 404 #endif
 405         vp = (struct cmu_vend *)cp;
 406
 407         if (vp->v_smask.s_addr != 0) {
 408                 smask = vp->v_smask.s_addr;
 409         }
 410         if (vp->v_dgate.s_addr != 0) {
 411                 gateip = vp->v_dgate;
 412         }
 413 }
 414 #endif