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net.c revision 1.20 
      1 /*	$NetBSD: net.c,v 1.20 1997/12/26 22:41:30 scottr 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 udphdr *uh;
     74 	register u_char *ea;
     75 
     76 #ifdef NET_DEBUG
     77  	if (debug) {
     78 		printf("sendudp: d=%lx called.\n", (long)d);
     79 		if (d) {
     80 			printf("saddr: %s:%d",
     81 			    inet_ntoa(d->myip), ntohs(d->myport));
     82 			printf(" daddr: %s:%d\n",
     83 			    inet_ntoa(d->destip), ntohs(d->destport));
     84 		}
     85 	}
     86 #endif
     87 
     88 	uh = (struct udphdr *)pkt - 1;
     89 	ip = (struct ip *)uh - 1;
     90 	len += sizeof(*ip) + sizeof(*uh);
     91 
     92 	bzero(ip, sizeof(*ip) + sizeof(*uh));
     93 
     94 	ip->ip_v = IPVERSION;			/* half-char */
     95 	ip->ip_hl = sizeof(*ip) >> 2;		/* half-char */
     96 	ip->ip_len = htons(len);
     97 	ip->ip_p = IPPROTO_UDP;			/* char */
     98 	ip->ip_ttl = IP_TTL;			/* char */
     99 	ip->ip_src = d->myip;
    100 	ip->ip_dst = d->destip;
    101 	ip->ip_sum = in_cksum(ip, sizeof(*ip));	 /* short, but special */
    102 
    103 	uh->uh_sport = d->myport;
    104 	uh->uh_dport = d->destport;
    105 	uh->uh_ulen = htons(len - sizeof(*ip));
    106 
    107 #ifndef UDP_NO_CKSUM
    108 	{
    109 		register struct udpiphdr *ui;
    110 		struct ip tip;
    111 
    112 		/* Calculate checksum (must save and restore ip header) */
    113 		tip = *ip;
    114 		ui = (struct udpiphdr *)ip;
    115 		bzero(ui->ui_x1, sizeof(ui->ui_x1));
    116 		ui->ui_len = uh->uh_ulen;
    117 		uh->uh_sum = in_cksum(ui, len);
    118 		*ip = tip;
    119 	}
    120 #endif
    121 
    122 	if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
    123 	    netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
    124 		ea = arpwhohas(d, ip->ip_dst);
    125 	else
    126 		ea = arpwhohas(d, gateip);
    127 
    128 	cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
    129 	if (cc == -1)
    130 		return (-1);
    131 	if (cc != len)
    132 		panic("sendudp: bad write (%d != %d)", cc, len);
    133 	return (cc - (sizeof(*ip) + sizeof(*uh)));
    134 }
    135 
    136 /*
    137  * Receive a UDP packet and validate it is for us.
    138  * Caller leaves room for the headers (Ether, IP, UDP)
    139  */
    140 ssize_t
    141 readudp(d, pkt, len, tleft)
    142 	register struct iodesc *d;
    143 	register void *pkt;
    144 	register size_t len;
    145 	time_t tleft;
    146 {
    147 	register ssize_t n;
    148 	register size_t hlen;
    149 	register struct ip *ip;
    150 	register struct udphdr *uh;
    151 	u_int16_t etype;	/* host order */
    152 
    153 #ifdef NET_DEBUG
    154 	if (debug)
    155 		printf("readudp: called\n");
    156 #endif
    157 
    158 	uh = (struct udphdr *)pkt - 1;
    159 	ip = (struct ip *)uh - 1;
    160 
    161 	n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
    162 	if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
    163 		return -1;
    164 
    165 	/* Ethernet address checks now in readether() */
    166 
    167 	/* Need to respond to ARP requests. */
    168 	if (etype == ETHERTYPE_ARP) {
    169 		struct arphdr *ah = (void *)ip;
    170 		if (ah->ar_op == htons(ARPOP_REQUEST)) {
    171 			/* Send ARP reply */
    172 			arp_reply(d, ah);
    173 		}
    174 		return -1;
    175 	}
    176 
    177 	if (etype != ETHERTYPE_IP) {
    178 #ifdef NET_DEBUG
    179 		if (debug)
    180 			printf("readudp: not IP. ether_type=%x\n", etype);
    181 #endif
    182 		return -1;
    183 	}
    184 
    185 	/* Check ip header */
    186 	if (ip->ip_v != IPVERSION ||
    187 	    ip->ip_p != IPPROTO_UDP) {	/* half char */
    188 #ifdef NET_DEBUG
    189 		if (debug)
    190 			printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
    191 #endif
    192 		return -1;
    193 	}
    194 
    195 	hlen = ip->ip_hl << 2;
    196 	if (hlen < sizeof(*ip) ||
    197 	    in_cksum(ip, hlen) != 0) {
    198 #ifdef NET_DEBUG
    199 		if (debug)
    200 			printf("readudp: short hdr or bad cksum.\n");
    201 #endif
    202 		return -1;
    203 	}
    204 	if (n < ntohs(ip->ip_len)) {
    205 #ifdef NET_DEBUG
    206 		if (debug)
    207 			printf("readudp: bad length %d < %d.\n",
    208 			       (int)n, ntohs(ip->ip_len));
    209 #endif
    210 		return -1;
    211 	}
    212 	if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
    213 #ifdef NET_DEBUG
    214 		if (debug) {
    215 			printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
    216 			printf("%s\n", inet_ntoa(ip->ip_dst));
    217 		}
    218 #endif
    219 		return -1;
    220 	}
    221 
    222 	/* If there were ip options, make them go away */
    223 	if (hlen != sizeof(*ip)) {
    224 		bcopy(((u_char *)ip) + hlen, uh, len - hlen);
    225 		ip->ip_len = htons(sizeof(*ip));
    226 		n -= hlen - sizeof(*ip);
    227 	}
    228 	if (uh->uh_dport != d->myport) {
    229 #ifdef NET_DEBUG
    230 		if (debug)
    231 			printf("readudp: bad dport %d != %d\n",
    232 				d->myport, ntohs(uh->uh_dport));
    233 #endif
    234 		return -1;
    235 	}
    236 
    237 #ifndef UDP_NO_CKSUM
    238 	if (uh->uh_sum) {
    239 		register struct udpiphdr *ui;
    240 		struct ip tip;
    241 
    242 		n = ntohs(uh->uh_ulen) + sizeof(*ip);
    243 		if (n > RECV_SIZE - ETHER_SIZE) {
    244 			printf("readudp: huge packet, udp len %d\n", (int)n);
    245 			return -1;
    246 		}
    247 
    248 		/* Check checksum (must save and restore ip header) */
    249 		tip = *ip;
    250 		ui = (struct udpiphdr *)ip;
    251 		bzero(ui->ui_x1, sizeof(ui->ui_x1));
    252 		ui->ui_len = uh->uh_ulen;
    253 		if (in_cksum(ui, n) != 0) {
    254 #ifdef NET_DEBUG
    255 			if (debug)
    256 				printf("readudp: bad cksum\n");
    257 #endif
    258 			*ip = tip;
    259 			return -1;
    260 		}
    261 		*ip = tip;
    262 	}
    263 #endif
    264 	if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
    265 #ifdef NET_DEBUG
    266 		if (debug)
    267 			printf("readudp: bad udp len %d < %d\n",
    268 				ntohs(uh->uh_ulen), (int)sizeof(*uh));
    269 #endif
    270 		return -1;
    271 	}
    272 
    273 	n -= sizeof(*ip) + sizeof(*uh);
    274 	return (n);
    275 }
    276 
    277 /*
    278  * Send a packet and wait for a reply, with exponential backoff.
    279  *
    280  * The send routine must return the actual number of bytes written,
    281  * or -1 on error.
    282  *
    283  * The receive routine can indicate success by returning the number of
    284  * bytes read; it can return 0 to indicate EOF; it can return -1 with a
    285  * non-zero errno to indicate failure; finally, it can return -1 with a
    286  * zero errno to indicate it isn't done yet.
    287  */
    288 ssize_t
    289 sendrecv(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
    290 	register struct iodesc *d;
    291 	register ssize_t (*sproc)(struct iodesc *, void *, size_t);
    292 	register void *sbuf;
    293 	register size_t ssize;
    294 	register ssize_t (*rproc)(struct iodesc *, void *, size_t, time_t);
    295 	register void *rbuf;
    296 	register size_t rsize;
    297 {
    298 	register ssize_t cc;
    299 	register time_t t, tmo, tlast;
    300 	long tleft;
    301 
    302 #ifdef NET_DEBUG
    303 	if (debug)
    304 		printf("sendrecv: called\n");
    305 #endif
    306 
    307 	tmo = MINTMO;
    308 	tlast = tleft = 0;
    309 	t = getsecs();
    310 	for (;;) {
    311 		if (tleft <= 0) {
    312 			if (tmo >= MAXTMO) {
    313 				errno = ETIMEDOUT;
    314 				return -1;
    315 			}
    316 			cc = (*sproc)(d, sbuf, ssize);
    317 			if (cc != -1 && cc < ssize)
    318 				panic("sendrecv: short write! (%d < %d)",
    319 				    cc, ssize);
    320 
    321 			tleft = tmo;
    322 			tmo <<= 1;
    323 			if (tmo > MAXTMO)
    324 				tmo = MAXTMO;
    325 
    326 			if (cc == -1) {
    327 				/* Error on transmit; wait before retrying */
    328 				while ((getsecs() - t) < tmo);
    329 				tleft = 0;
    330 				continue;
    331 			}
    332 
    333 			tlast = t;
    334 		}
    335 
    336 		/* Try to get a packet and process it. */
    337 		cc = (*rproc)(d, rbuf, rsize, tleft);
    338 		/* Return on data, EOF or real error. */
    339 		if (cc != -1 || errno != 0)
    340 			return (cc);
    341 
    342 		/* Timed out or didn't get the packet we're waiting for */
    343 		t = getsecs();
    344 		tleft -= t - tlast;
    345 		tlast = t;
    346 	}
    347 }
    348 
    349 /*
    350  * Like inet_addr() in the C library, but we only accept base-10.
    351  * Return values are in network order.
    352  */
    353 n_long
    354 inet_addr(cp)
    355 	char *cp;
    356 {
    357 	register u_long val;
    358 	register int n;
    359 	register char c;
    360 	u_int parts[4];
    361 	register u_int *pp = parts;
    362 
    363 	for (;;) {
    364 		/*
    365 		 * Collect number up to ``.''.
    366 		 * Values are specified as for C:
    367 		 * 0x=hex, 0=octal, other=decimal.
    368 		 */
    369 		val = 0;
    370 		while ((c = *cp) != '\0') {
    371 			if (c >= '0' && c <= '9') {
    372 				val = (val * 10) + (c - '0');
    373 				cp++;
    374 				continue;
    375 			}
    376 			break;
    377 		}
    378 		if (*cp == '.') {
    379 			/*
    380 			 * Internet format:
    381 			 *	a.b.c.d
    382 			 *	a.b.c	(with c treated as 16-bits)
    383 			 *	a.b	(with b treated as 24 bits)
    384 			 */
    385 			if (pp >= parts + 3 || val > 0xff)
    386 				goto bad;
    387 			*pp++ = val, cp++;
    388 		} else
    389 			break;
    390 	}
    391 	/*
    392 	 * Check for trailing characters.
    393 	 */
    394 	if (*cp != '\0')
    395 		goto bad;
    396 
    397 	/*
    398 	 * Concoct the address according to
    399 	 * the number of parts specified.
    400 	 */
    401 	n = pp - parts + 1;
    402 	switch (n) {
    403 
    404 	case 1:				/* a -- 32 bits */
    405 		break;
    406 
    407 	case 2:				/* a.b -- 8.24 bits */
    408 		if (val > 0xffffff)
    409 			goto bad;
    410 		val |= parts[0] << 24;
    411 		break;
    412 
    413 	case 3:				/* a.b.c -- 8.8.16 bits */
    414 		if (val > 0xffff)
    415 			goto bad;
    416 		val |= (parts[0] << 24) | (parts[1] << 16);
    417 		break;
    418 
    419 	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
    420 		if (val > 0xff)
    421 			goto bad;
    422 		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
    423 		break;
    424 	}
    425 
    426 	return (htonl(val));
    427  bad:
    428 	return (htonl(INADDR_NONE));
    429 }
    430 
    431 char *
    432 inet_ntoa(ia)
    433 	struct in_addr ia;
    434 {
    435 	return (intoa(ia.s_addr));
    436 }
    437 
    438 /* Similar to inet_ntoa() */
    439 char *
    440 intoa(addr)
    441 	register n_long addr;
    442 {
    443 	register char *cp;
    444 	register u_int byte;
    445 	register int n;
    446 	static char buf[17];	/* strlen(".255.255.255.255") + 1 */
    447 
    448 	NTOHL(addr);
    449 	cp = &buf[sizeof buf];
    450 	*--cp = '\0';
    451 
    452 	n = 4;
    453 	do {
    454 		byte = addr & 0xff;
    455 		*--cp = byte % 10 + '0';
    456 		byte /= 10;
    457 		if (byte > 0) {
    458 			*--cp = byte % 10 + '0';
    459 			byte /= 10;
    460 			if (byte > 0)
    461 				*--cp = byte + '0';
    462 		}
    463 		*--cp = '.';
    464 		addr >>= 8;
    465 	} while (--n > 0);
    466 
    467 	return (cp+1);
    468 }
    469 
    470 static char *
    471 number(s, n)
    472 	char *s;
    473 	int *n;
    474 {
    475 	for (*n = 0; isdigit(*s); s++)
    476 		*n = (*n * 10) + *s - '0';
    477 	return s;
    478 }
    479 
    480 n_long
    481 ip_convertaddr(p)
    482 	char *p;
    483 {
    484 #define IP_ANYADDR	0
    485 	n_long addr = 0, n;
    486 
    487 	if (p == (char *)0 || *p == '\0')
    488 		return IP_ANYADDR;
    489 	p = number(p, &n);
    490 	addr |= (n << 24) & 0xff000000;
    491 	if (*p == '\0' || *p++ != '.')
    492 		return IP_ANYADDR;
    493 	p = number(p, &n);
    494 	addr |= (n << 16) & 0xff0000;
    495 	if (*p == '\0' || *p++ != '.')
    496 		return IP_ANYADDR;
    497 	p = number(p, &n);
    498 	addr |= (n << 8) & 0xff00;
    499 	if (*p == '\0' || *p++ != '.')
    500 		return IP_ANYADDR;
    501 	p = number(p, &n);
    502 	addr |= n & 0xff;
    503 	if (*p != '\0')
    504 		return IP_ANYADDR;
    505 
    506 	return htonl(addr);
    507 }
    508