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net.c revision 1.12 
      1 /*	$NetBSD: net.c,v 1.12 1995/12/13 23:38:10 pk 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 #include <string.h>
     46 
     47 #include <net/if.h>
     48 
     49 #include <netinet/in.h>
     50 #include <netinet/if_ether.h>
     51 #include <netinet/in_systm.h>
     52 #include <netinet/ip.h>
     53 #include <netinet/ip_var.h>
     54 #include <netinet/udp.h>
     55 #include <netinet/udp_var.h>
     56 
     57 #include "stand.h"
     58 #include "net.h"
     59 
     60 /* Caller must leave room for ethernet, ip and udp headers in front!! */
     61 ssize_t
     62 sendudp(d, pkt, len)
     63 	register struct iodesc *d;
     64 	register void *pkt;
     65 	register size_t len;
     66 {
     67 	register ssize_t cc;
     68 	register struct ip *ip;
     69 	register struct udpiphdr *ui;
     70 	register struct udphdr *uh;
     71 	register u_char *ea;
     72 	struct ip tip;
     73 
     74 #ifdef NET_DEBUG
     75  	if (debug) {
     76 		printf("sendudp: d=%x called.\n", (u_int)d);
     77 		if (d) {
     78 			printf("saddr: %s:%d",
     79 				inet_ntoa(d->myip), ntohs(d->myport));
     80 			printf(" daddr: %s:%d\n",
     81 				inet_ntoa(d->destip), ntohs(d->destport));
     82 		}
     83 	}
     84 #endif
     85 
     86 	uh = (struct udphdr *)pkt - 1;
     87 	ip = (struct ip *)uh - 1;
     88 	len += sizeof(*ip) + sizeof(*uh);
     89 
     90 	bzero(ip, sizeof(*ip) + sizeof(*uh));
     91 
     92 	ip->ip_v = IPVERSION;			/* half-char */
     93 	ip->ip_hl = sizeof(*ip) >> 2;		/* half-char */
     94 	ip->ip_len = htons(len);
     95 	ip->ip_p = IPPROTO_UDP;			/* char */
     96 	ip->ip_ttl = IP_TTL;			/* char */
     97 	ip->ip_src = d->myip;
     98 	ip->ip_dst = d->destip;
     99 	ip->ip_sum = in_cksum(ip, sizeof(*ip));	 /* short, but special */
    100 
    101 	uh->uh_sport = d->myport;
    102 	uh->uh_dport = d->destport;
    103 	uh->uh_ulen = htons(len - sizeof(*ip));
    104 
    105 	/* Calculate checksum (must save and restore ip header) */
    106 	tip = *ip;
    107 	ui = (struct udpiphdr *)ip;
    108 	bzero(ui->ui_x1, sizeof(ui->ui_x1));
    109 	ui->ui_len = uh->uh_ulen;
    110 	uh->uh_sum = in_cksum(ui, len);
    111 	*ip = tip;
    112 
    113 	if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
    114 	    netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
    115 		ea = arpwhohas(d, ip->ip_dst);
    116 	else
    117 		ea = arpwhohas(d, gateip);
    118 
    119 	cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
    120 	if (cc == -1)
    121 		return (-1);
    122 	if (cc != len)
    123 		panic("sendudp: bad write (%d != %d)", cc, len);
    124 	return (cc - (sizeof(*ip) + sizeof(*uh)));
    125 }
    126 
    127 /*
    128  * Receive a UDP packet and validate it is for us.
    129  * Caller leaves room for the headers (Ether, IP, UDP)
    130  */
    131 ssize_t
    132 readudp(d, pkt, len, tleft)
    133 	register struct iodesc *d;
    134 	register void *pkt;
    135 	register size_t len;
    136 	time_t tleft;
    137 {
    138 	register ssize_t n;
    139 	register size_t hlen;
    140 	register struct ip *ip;
    141 	register struct udphdr *uh;
    142 	register struct udpiphdr *ui;
    143 	struct ip tip;
    144 	u_int16_t etype;	/* host order */
    145 
    146 #ifdef NET_DEBUG
    147 	if (debug)
    148 		printf("readudp: called\n");
    149 #endif
    150 
    151 	uh = (struct udphdr *)pkt - 1;
    152 	ip = (struct ip *)uh - 1;
    153 
    154 	n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
    155 	if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
    156 		return -1;
    157 
    158 	/* Ethernet address checks now in readether() */
    159 
    160 	/* Need to respond to ARP requests. */
    161 	if (etype == ETHERTYPE_ARP) {
    162 		struct arphdr *ah = (void *)ip;
    163 		if (ah->ar_op == htons(ARPOP_REQUEST)) {
    164 			/* Send ARP reply */
    165 			arp_reply(d, ah);
    166 		}
    167 		return -1;
    168 	}
    169 
    170 	if (etype != ETHERTYPE_IP) {
    171 #ifdef NET_DEBUG
    172 		if (debug)
    173 			printf("readudp: not IP. ether_type=%x\n", etype);
    174 #endif
    175 		return -1;
    176 	}
    177 
    178 	/* Check ip header */
    179 	if (ip->ip_v != IPVERSION ||
    180 	    ip->ip_p != IPPROTO_UDP) {	/* half char */
    181 #ifdef NET_DEBUG
    182 		if (debug)
    183 			printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
    184 #endif
    185 		return -1;
    186 	}
    187 
    188 	hlen = ip->ip_hl << 2;
    189 	if (hlen < sizeof(*ip) ||
    190 	    in_cksum(ip, hlen) != 0) {
    191 #ifdef NET_DEBUG
    192 		if (debug)
    193 			printf("readudp: short hdr or bad cksum.\n");
    194 #endif
    195 		return -1;
    196 	}
    197 	NTOHS(ip->ip_len);
    198 	if (n < ip->ip_len) {
    199 #ifdef NET_DEBUG
    200 		if (debug)
    201 			printf("readudp: bad length %d < %d.\n", n, ip->ip_len);
    202 #endif
    203 		return -1;
    204 	}
    205 	if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
    206 #ifdef NET_DEBUG
    207 		if (debug) {
    208 			printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
    209 			printf("%s\n", inet_ntoa(ip->ip_dst));
    210 		}
    211 #endif
    212 		return -1;
    213 	}
    214 
    215 	/* If there were ip options, make them go away */
    216 	if (hlen != sizeof(*ip)) {
    217 		bcopy(((u_char *)ip) + hlen, uh, len - hlen);
    218 		ip->ip_len = sizeof(*ip);
    219 		n -= hlen - sizeof(*ip);
    220 	}
    221 	if (uh->uh_dport != d->myport) {
    222 #ifdef NET_DEBUG
    223 		if (debug)
    224 			printf("readudp: bad dport %d != %d\n",
    225 				d->myport, ntohs(uh->uh_dport));
    226 #endif
    227 		return -1;
    228 	}
    229 
    230 	if (uh->uh_sum) {
    231 		n = ntohs(uh->uh_ulen) + sizeof(*ip);
    232 		if (n > RECV_SIZE - ETHER_SIZE) {
    233 			printf("readudp: huge packet, udp len %d\n", n);
    234 			return -1;
    235 		}
    236 
    237 		/* Check checksum (must save and restore ip header) */
    238 		tip = *ip;
    239 		ui = (struct udpiphdr *)ip;
    240 		bzero(ui->ui_x1, sizeof(ui->ui_x1));
    241 		ui->ui_len = uh->uh_ulen;
    242 		if (in_cksum(ui, n) != 0) {
    243 #ifdef NET_DEBUG
    244 			if (debug)
    245 				printf("readudp: bad cksum\n");
    246 #endif
    247 			*ip = tip;
    248 			return -1;
    249 		}
    250 		*ip = tip;
    251 	}
    252 	NTOHS(uh->uh_dport);
    253 	NTOHS(uh->uh_sport);
    254 	NTOHS(uh->uh_ulen);
    255 	if (uh->uh_ulen < sizeof(*uh)) {
    256 #ifdef NET_DEBUG
    257 		if (debug)
    258 			printf("readudp: bad udp len %d < %d\n",
    259 				uh->uh_ulen, sizeof(*uh));
    260 #endif
    261 		return -1;
    262 	}
    263 
    264 	n -= sizeof(*ip) + sizeof(*uh);
    265 	return (n);
    266 }
    267 
    268 /*
    269  * Send a packet and wait for a reply, with exponential backoff.
    270  *
    271  * The send routine must return the actual number of bytes written.
    272  *
    273  * The receive routine can indicate success by returning the number of
    274  * bytes read; it can return 0 to indicate EOF; it can return -1 with a
    275  * non-zero errno to indicate failure; finally, it can return -1 with a
    276  * zero errno to indicate it isn't done yet.
    277  */
    278 ssize_t
    279 sendrecv(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
    280 	register struct iodesc *d;
    281 	register ssize_t (*sproc)(struct iodesc *, void *, size_t);
    282 	register void *sbuf;
    283 	register size_t ssize;
    284 	register ssize_t (*rproc)(struct iodesc *, void *, size_t, time_t);
    285 	register void *rbuf;
    286 	register size_t rsize;
    287 {
    288 	register ssize_t cc;
    289 	register time_t t, tmo, tlast;
    290 	long tleft;
    291 
    292 #ifdef NET_DEBUG
    293 	if (debug)
    294 		printf("sendrecv: called\n");
    295 #endif
    296 
    297 	tmo = MINTMO;
    298 	tlast = tleft = 0;
    299 	t = getsecs();
    300 	for (;;) {
    301 		if (tleft <= 0) {
    302 			if (tmo >= MAXTMO) {
    303 				errno = ETIMEDOUT;
    304 				return -1;
    305 			}
    306 			cc = (*sproc)(d, sbuf, ssize);
    307 			if (cc == -1 || cc < ssize)
    308 				panic("sendrecv: short write! (%d < %d)",
    309 				    cc, ssize);
    310 
    311 			tleft = tmo;
    312 			tmo <<= 1;
    313 			if (tmo > MAXTMO)
    314 				tmo = MAXTMO;
    315 			tlast = t;
    316 		}
    317 
    318 		/* Try to get a packet and process it. */
    319 		cc = (*rproc)(d, rbuf, rsize, tleft);
    320 		/* Return on data, EOF or real error. */
    321 		if (cc != -1 || errno != 0)
    322 			return (cc);
    323 
    324 		/* Timed out or didn't get the packet we're waiting for */
    325 		t = getsecs();
    326 		tleft -= t - tlast;
    327 		tlast = t;
    328 	}
    329 }
    330 
    331 /*
    332  * Like inet_addr() in the C library, but we only accept base-10.
    333  * Return values are in network order.
    334  */
    335 n_long
    336 inet_addr(cp)
    337 	char *cp;
    338 {
    339 	register u_long val;
    340 	register int n;
    341 	register char c;
    342 	u_int parts[4];
    343 	register u_int *pp = parts;
    344 
    345 	for (;;) {
    346 		/*
    347 		 * Collect number up to ``.''.
    348 		 * Values are specified as for C:
    349 		 * 0x=hex, 0=octal, other=decimal.
    350 		 */
    351 		val = 0;
    352 		while ((c = *cp) != '\0') {
    353 			if (c >= '0' && c <= '9') {
    354 				val = (val * 10) + (c - '0');
    355 				cp++;
    356 				continue;
    357 			}
    358 			break;
    359 		}
    360 		if (*cp == '.') {
    361 			/*
    362 			 * Internet format:
    363 			 *	a.b.c.d
    364 			 *	a.b.c	(with c treated as 16-bits)
    365 			 *	a.b	(with b treated as 24 bits)
    366 			 */
    367 			if (pp >= parts + 3 || val > 0xff)
    368 				goto bad;
    369 			*pp++ = val, cp++;
    370 		} else
    371 			break;
    372 	}
    373 	/*
    374 	 * Check for trailing characters.
    375 	 */
    376 	if (*cp != '\0')
    377 		goto bad;
    378 
    379 	/*
    380 	 * Concoct the address according to
    381 	 * the number of parts specified.
    382 	 */
    383 	n = pp - parts + 1;
    384 	switch (n) {
    385 
    386 	case 1:				/* a -- 32 bits */
    387 		break;
    388 
    389 	case 2:				/* a.b -- 8.24 bits */
    390 		if (val > 0xffffff)
    391 			goto bad;
    392 		val |= parts[0] << 24;
    393 		break;
    394 
    395 	case 3:				/* a.b.c -- 8.8.16 bits */
    396 		if (val > 0xffff)
    397 			goto bad;
    398 		val |= (parts[0] << 24) | (parts[1] << 16);
    399 		break;
    400 
    401 	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
    402 		if (val > 0xff)
    403 			goto bad;
    404 		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
    405 		break;
    406 	}
    407 
    408 	return (htonl(val));
    409  bad:
    410 	return (htonl(INADDR_NONE));
    411 }
    412 
    413 char *
    414 inet_ntoa(ia)
    415 	struct in_addr ia;
    416 {
    417 	return (intoa(ia.s_addr));
    418 }
    419 
    420 /* Similar to inet_ntoa() */
    421 char *
    422 intoa(addr)
    423 	register n_long addr;
    424 {
    425 	register char *cp;
    426 	register u_int byte;
    427 	register int n;
    428 	static char buf[17];	/* strlen(".255.255.255.255") + 1 */
    429 
    430 	NTOHL(addr);
    431 	cp = &buf[sizeof buf];
    432 	*--cp = '\0';
    433 
    434 	n = 4;
    435 	do {
    436 		byte = addr & 0xff;
    437 		*--cp = byte % 10 + '0';
    438 		byte /= 10;
    439 		if (byte > 0) {
    440 			*--cp = byte % 10 + '0';
    441 			byte /= 10;
    442 			if (byte > 0)
    443 				*--cp = byte + '0';
    444 		}
    445 		*--cp = '.';
    446 		addr >>= 8;
    447 	} while (--n > 0);
    448 
    449 	return (cp+1);
    450 }
    451 
    452 static char *
    453 number(s, n)
    454 	char *s;
    455 	int *n;
    456 {
    457 	for (*n = 0; isdigit(*s); s++)
    458 		*n = (*n * 10) + *s - '0';
    459 	return s;
    460 }
    461 
    462 n_long
    463 ip_convertaddr(p)
    464 	char *p;
    465 {
    466 #define IP_ANYADDR	0
    467 	n_long addr = 0, n;
    468 
    469 	if (p == (char *)0 || *p == '\0')
    470 		return IP_ANYADDR;
    471 	p = number(p, &n);
    472 	addr |= (n << 24) & 0xff000000;
    473 	if (*p == '\0' || *p++ != '.')
    474 		return IP_ANYADDR;
    475 	p = number(p, &n);
    476 	addr |= (n << 16) & 0xff0000;
    477 	if (*p == '\0' || *p++ != '.')
    478 		return IP_ANYADDR;
    479 	p = number(p, &n);
    480 	addr |= (n << 8) & 0xff00;
    481 	if (*p == '\0' || *p++ != '.')
    482 		return IP_ANYADDR;
    483 	p = number(p, &n);
    484 	addr |= n & 0xff;
    485 	if (*p != '\0')
    486 		return IP_ANYADDR;
    487 
    488 	return htonl(addr);
    489 }
    490