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net.c revision 1.17 
      1 /*	$NetBSD: net.c,v 1.17 1997/07/07 15:52:51 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  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the University of
     22  *	California, Lawrence Berkeley Laboratory and its contributors.
     23  * 4. Neither the name of the University nor the names of its contributors
     24  *    may be used to endorse or promote products derived from this software
     25  *    without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     37  * SUCH DAMAGE.
     38  *
     39  * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
     40  */
     41 
     42 #include <sys/param.h>
     43 #include <sys/socket.h>
     44 
     45 #ifdef _STANDALONE
     46 #include <lib/libkern/libkern.h>
     47 #else
     48 #include <string.h>
     49 #endif
     50 
     51 #include <net/if.h>
     52 #include <net/if_ether.h>
     53 
     54 #include <netinet/in.h>
     55 #include <netinet/in_systm.h>
     56 #include <netinet/ip.h>
     57 #include <netinet/ip_var.h>
     58 #include <netinet/udp.h>
     59 #include <netinet/udp_var.h>
     60 
     61 #include "stand.h"
     62 #include "net.h"
     63 
     64 /* Caller must leave room for ethernet, ip and udp headers in front!! */
     65 ssize_t
     66 sendudp(d, pkt, len)
     67 	register struct iodesc *d;
     68 	register void *pkt;
     69 	register size_t len;
     70 {
     71 	register ssize_t cc;
     72 	register struct ip *ip;
     73 	register struct udpiphdr *ui;
     74 	register struct udphdr *uh;
     75 	register u_char *ea;
     76 	struct ip tip;
     77 
     78 #ifdef NET_DEBUG
     79  	if (debug) {
     80 		printf("sendudp: d=%x called.\n", (u_int)d);
     81 		if (d) {
     82 			printf("saddr: %s:%d",
     83 			    inet_ntoa(d->myip), ntohs(d->myport));
     84 			printf(" daddr: %s:%d\n",
     85 			    inet_ntoa(d->destip), ntohs(d->destport));
     86 		}
     87 	}
     88 #endif
     89 
     90 	uh = (struct udphdr *)pkt - 1;
     91 	ip = (struct ip *)uh - 1;
     92 	len += sizeof(*ip) + sizeof(*uh);
     93 
     94 	bzero(ip, sizeof(*ip) + sizeof(*uh));
     95 
     96 	ip->ip_v = IPVERSION;			/* half-char */
     97 	ip->ip_hl = sizeof(*ip) >> 2;		/* half-char */
     98 	ip->ip_len = htons(len);
     99 	ip->ip_p = IPPROTO_UDP;			/* char */
    100 	ip->ip_ttl = IP_TTL;			/* char */
    101 	ip->ip_src = d->myip;
    102 	ip->ip_dst = d->destip;
    103 	ip->ip_sum = in_cksum(ip, sizeof(*ip));	 /* short, but special */
    104 
    105 	uh->uh_sport = d->myport;
    106 	uh->uh_dport = d->destport;
    107 	uh->uh_ulen = htons(len - sizeof(*ip));
    108 
    109 	/* Calculate checksum (must save and restore ip header) */
    110 	tip = *ip;
    111 	ui = (struct udpiphdr *)ip;
    112 	bzero(ui->ui_x1, sizeof(ui->ui_x1));
    113 	ui->ui_len = uh->uh_ulen;
    114 	uh->uh_sum = in_cksum(ui, len);
    115 	*ip = tip;
    116 
    117 	if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
    118 	    netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
    119 		ea = arpwhohas(d, ip->ip_dst);
    120 	else
    121 		ea = arpwhohas(d, gateip);
    122 
    123 	cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
    124 	if (cc == -1)
    125 		return (-1);
    126 	if (cc != len)
    127 		panic("sendudp: bad write (%d != %d)", cc, len);
    128 	return (cc - (sizeof(*ip) + sizeof(*uh)));
    129 }
    130 
    131 /*
    132  * Receive a UDP packet and validate it is for us.
    133  * Caller leaves room for the headers (Ether, IP, UDP)
    134  */
    135 ssize_t
    136 readudp(d, pkt, len, tleft)
    137 	register struct iodesc *d;
    138 	register void *pkt;
    139 	register size_t len;
    140 	time_t tleft;
    141 {
    142 	register ssize_t n;
    143 	register size_t hlen;
    144 	register struct ip *ip;
    145 	register struct udphdr *uh;
    146 	register struct udpiphdr *ui;
    147 	struct ip tip;
    148 	u_int16_t etype;	/* host order */
    149 
    150 #ifdef NET_DEBUG
    151 	if (debug)
    152 		printf("readudp: called\n");
    153 #endif
    154 
    155 	uh = (struct udphdr *)pkt - 1;
    156 	ip = (struct ip *)uh - 1;
    157 
    158 	n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
    159 	if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
    160 		return -1;
    161 
    162 	/* Ethernet address checks now in readether() */
    163 
    164 	/* Need to respond to ARP requests. */
    165 	if (etype == ETHERTYPE_ARP) {
    166 		struct arphdr *ah = (void *)ip;
    167 		if (ah->ar_op == htons(ARPOP_REQUEST)) {
    168 			/* Send ARP reply */
    169 			arp_reply(d, ah);
    170 		}
    171 		return -1;
    172 	}
    173 
    174 	if (etype != ETHERTYPE_IP) {
    175 #ifdef NET_DEBUG
    176 		if (debug)
    177 			printf("readudp: not IP. ether_type=%x\n", etype);
    178 #endif
    179 		return -1;
    180 	}
    181 
    182 	/* Check ip header */
    183 	if (ip->ip_v != IPVERSION ||
    184 	    ip->ip_p != IPPROTO_UDP) {	/* half char */
    185 #ifdef NET_DEBUG
    186 		if (debug)
    187 			printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
    188 #endif
    189 		return -1;
    190 	}
    191 
    192 	hlen = ip->ip_hl << 2;
    193 	if (hlen < sizeof(*ip) ||
    194 	    in_cksum(ip, hlen) != 0) {
    195 #ifdef NET_DEBUG
    196 		if (debug)
    197 			printf("readudp: short hdr or bad cksum.\n");
    198 #endif
    199 		return -1;
    200 	}
    201 	NTOHS(ip->ip_len);
    202 	if (n < ip->ip_len) {
    203 #ifdef NET_DEBUG
    204 		if (debug)
    205 			printf("readudp: bad length %d < %d.\n", n, ip->ip_len);
    206 #endif
    207 		return -1;
    208 	}
    209 	if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
    210 #ifdef NET_DEBUG
    211 		if (debug) {
    212 			printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
    213 			printf("%s\n", inet_ntoa(ip->ip_dst));
    214 		}
    215 #endif
    216 		return -1;
    217 	}
    218 
    219 	/* If there were ip options, make them go away */
    220 	if (hlen != sizeof(*ip)) {
    221 		bcopy(((u_char *)ip) + hlen, uh, len - hlen);
    222 		ip->ip_len = sizeof(*ip);
    223 		n -= hlen - sizeof(*ip);
    224 	}
    225 	if (uh->uh_dport != d->myport) {
    226 #ifdef NET_DEBUG
    227 		if (debug)
    228 			printf("readudp: bad dport %d != %d\n",
    229 				d->myport, ntohs(uh->uh_dport));
    230 #endif
    231 		return -1;
    232 	}
    233 
    234 	if (uh->uh_sum) {
    235 		n = ntohs(uh->uh_ulen) + sizeof(*ip);
    236 		if (n > RECV_SIZE - ETHER_SIZE) {
    237 			printf("readudp: huge packet, udp len %d\n", n);
    238 			return -1;
    239 		}
    240 
    241 		/* Check checksum (must save and restore ip header) */
    242 		tip = *ip;
    243 		ui = (struct udpiphdr *)ip;
    244 		bzero(ui->ui_x1, sizeof(ui->ui_x1));
    245 		ui->ui_len = uh->uh_ulen;
    246 		if (in_cksum(ui, n) != 0) {
    247 #ifdef NET_DEBUG
    248 			if (debug)
    249 				printf("readudp: bad cksum\n");
    250 #endif
    251 			*ip = tip;
    252 			return -1;
    253 		}
    254 		*ip = tip;
    255 	}
    256 	NTOHS(uh->uh_dport);
    257 	NTOHS(uh->uh_sport);
    258 	NTOHS(uh->uh_ulen);
    259 	if (uh->uh_ulen < sizeof(*uh)) {
    260 #ifdef NET_DEBUG
    261 		if (debug)
    262 			printf("readudp: bad udp len %d < %d\n",
    263 				uh->uh_ulen, sizeof(*uh));
    264 #endif
    265 		return -1;
    266 	}
    267 
    268 	n -= sizeof(*ip) + sizeof(*uh);
    269 	return (n);
    270 }
    271 
    272 /*
    273  * Send a packet and wait for a reply, with exponential backoff.
    274  *
    275  * The send routine must return the actual number of bytes written.
    276  *
    277  * The receive routine can indicate success by returning the number of
    278  * bytes read; it can return 0 to indicate EOF; it can return -1 with a
    279  * non-zero errno to indicate failure; finally, it can return -1 with a
    280  * zero errno to indicate it isn't done yet.
    281  */
    282 ssize_t
    283 sendrecv(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
    284 	register struct iodesc *d;
    285 	register ssize_t (*sproc)(struct iodesc *, void *, size_t);
    286 	register void *sbuf;
    287 	register size_t ssize;
    288 	register ssize_t (*rproc)(struct iodesc *, void *, size_t, time_t);
    289 	register void *rbuf;
    290 	register size_t rsize;
    291 {
    292 	register ssize_t cc;
    293 	register time_t t, tmo, tlast;
    294 	long tleft;
    295 
    296 #ifdef NET_DEBUG
    297 	if (debug)
    298 		printf("sendrecv: called\n");
    299 #endif
    300 
    301 	tmo = MINTMO;
    302 	tlast = tleft = 0;
    303 	t = getsecs();
    304 	for (;;) {
    305 		if (tleft <= 0) {
    306 			if (tmo >= MAXTMO) {
    307 				errno = ETIMEDOUT;
    308 				return -1;
    309 			}
    310 			cc = (*sproc)(d, sbuf, ssize);
    311 			if (cc == -1 || cc < ssize)
    312 				panic("sendrecv: short write! (%d < %d)",
    313 				    cc, ssize);
    314 
    315 			tleft = tmo;
    316 			tmo <<= 1;
    317 			if (tmo > MAXTMO)
    318 				tmo = MAXTMO;
    319 			tlast = t;
    320 		}
    321 
    322 		/* Try to get a packet and process it. */
    323 		cc = (*rproc)(d, rbuf, rsize, tleft);
    324 		/* Return on data, EOF or real error. */
    325 		if (cc != -1 || errno != 0)
    326 			return (cc);
    327 
    328 		/* Timed out or didn't get the packet we're waiting for */
    329 		t = getsecs();
    330 		tleft -= t - tlast;
    331 		tlast = t;
    332 	}
    333 }
    334 
    335 /*
    336  * Like inet_addr() in the C library, but we only accept base-10.
    337  * Return values are in network order.
    338  */
    339 n_long
    340 inet_addr(cp)
    341 	char *cp;
    342 {
    343 	register u_long val;
    344 	register int n;
    345 	register char c;
    346 	u_int parts[4];
    347 	register u_int *pp = parts;
    348 
    349 	for (;;) {
    350 		/*
    351 		 * Collect number up to ``.''.
    352 		 * Values are specified as for C:
    353 		 * 0x=hex, 0=octal, other=decimal.
    354 		 */
    355 		val = 0;
    356 		while ((c = *cp) != '\0') {
    357 			if (c >= '0' && c <= '9') {
    358 				val = (val * 10) + (c - '0');
    359 				cp++;
    360 				continue;
    361 			}
    362 			break;
    363 		}
    364 		if (*cp == '.') {
    365 			/*
    366 			 * Internet format:
    367 			 *	a.b.c.d
    368 			 *	a.b.c	(with c treated as 16-bits)
    369 			 *	a.b	(with b treated as 24 bits)
    370 			 */
    371 			if (pp >= parts + 3 || val > 0xff)
    372 				goto bad;
    373 			*pp++ = val, cp++;
    374 		} else
    375 			break;
    376 	}
    377 	/*
    378 	 * Check for trailing characters.
    379 	 */
    380 	if (*cp != '\0')
    381 		goto bad;
    382 
    383 	/*
    384 	 * Concoct the address according to
    385 	 * the number of parts specified.
    386 	 */
    387 	n = pp - parts + 1;
    388 	switch (n) {
    389 
    390 	case 1:				/* a -- 32 bits */
    391 		break;
    392 
    393 	case 2:				/* a.b -- 8.24 bits */
    394 		if (val > 0xffffff)
    395 			goto bad;
    396 		val |= parts[0] << 24;
    397 		break;
    398 
    399 	case 3:				/* a.b.c -- 8.8.16 bits */
    400 		if (val > 0xffff)
    401 			goto bad;
    402 		val |= (parts[0] << 24) | (parts[1] << 16);
    403 		break;
    404 
    405 	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
    406 		if (val > 0xff)
    407 			goto bad;
    408 		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
    409 		break;
    410 	}
    411 
    412 	return (htonl(val));
    413  bad:
    414 	return (htonl(INADDR_NONE));
    415 }
    416 
    417 char *
    418 inet_ntoa(ia)
    419 	struct in_addr ia;
    420 {
    421 	return (intoa(ia.s_addr));
    422 }
    423 
    424 /* Similar to inet_ntoa() */
    425 char *
    426 intoa(addr)
    427 	register n_long addr;
    428 {
    429 	register char *cp;
    430 	register u_int byte;
    431 	register int n;
    432 	static char buf[17];	/* strlen(".255.255.255.255") + 1 */
    433 
    434 	NTOHL(addr);
    435 	cp = &buf[sizeof buf];
    436 	*--cp = '\0';
    437 
    438 	n = 4;
    439 	do {
    440 		byte = addr & 0xff;
    441 		*--cp = byte % 10 + '0';
    442 		byte /= 10;
    443 		if (byte > 0) {
    444 			*--cp = byte % 10 + '0';
    445 			byte /= 10;
    446 			if (byte > 0)
    447 				*--cp = byte + '0';
    448 		}
    449 		*--cp = '.';
    450 		addr >>= 8;
    451 	} while (--n > 0);
    452 
    453 	return (cp+1);
    454 }
    455 
    456 static char *
    457 number(s, n)
    458 	char *s;
    459 	int *n;
    460 {
    461 	for (*n = 0; isdigit(*s); s++)
    462 		*n = (*n * 10) + *s - '0';
    463 	return s;
    464 }
    465 
    466 n_long
    467 ip_convertaddr(p)
    468 	char *p;
    469 {
    470 #define IP_ANYADDR	0
    471 	n_long addr = 0, n;
    472 
    473 	if (p == (char *)0 || *p == '\0')
    474 		return IP_ANYADDR;
    475 	p = number(p, &n);
    476 	addr |= (n << 24) & 0xff000000;
    477 	if (*p == '\0' || *p++ != '.')
    478 		return IP_ANYADDR;
    479 	p = number(p, &n);
    480 	addr |= (n << 16) & 0xff0000;
    481 	if (*p == '\0' || *p++ != '.')
    482 		return IP_ANYADDR;
    483 	p = number(p, &n);
    484 	addr |= (n << 8) & 0xff00;
    485 	if (*p == '\0' || *p++ != '.')
    486 		return IP_ANYADDR;
    487 	p = number(p, &n);
    488 	addr |= n & 0xff;
    489 	if (*p != '\0')
    490 		return IP_ANYADDR;
    491 
    492 	return htonl(addr);
    493 }
    494