1 files changed, 310 insertions, 0 deletions
diff --git a/lib/libstand/arp.c b/lib/libstand/arp.c
new file mode 100644
index 0000000..4736b51
--- /dev/null
+++ b/lib/libstand/arp.c
@@ -0,0 +1,310 @@
+/*	$NetBSD: arp.c,v 1.18 1997/07/07 15:52:49 drochner Exp $	*/
+
+/*
+ * Copyright (c) 1992 Regents of the University of California.
+ * All rights reserved.
+ *
+ * This software was developed by the Computer Systems Engineering group
+ * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
+ * contributed to Berkeley.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Lawrence Berkeley Laboratory and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp  (LBL)
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+
+#include <netinet/in_systm.h>
+
+#include <string.h>
+
+#include "stand.h"
+#include "net.h"
+
+/* Cache stuff */
+#define ARP_NUM 8			/* need at most 3 arp entries */
+
+struct arp_list {
+	struct in_addr	addr;
+	u_char		ea[6];
+} arp_list[ARP_NUM] = {
+	/* XXX - net order `INADDR_BROADCAST' must be a constant */
+	{ {0xffffffff}, BA }
+};
+int arp_num = 1;
+
+/* Local forwards */
+static	ssize_t arpsend(struct iodesc *, void *, size_t);
+static	ssize_t arprecv(struct iodesc *, void *, size_t, time_t);
+
+/* Broadcast an ARP packet, asking who has addr on interface d */
+u_char *
+arpwhohas(d, addr)
+	register struct iodesc *d;
+	struct in_addr addr;
+{
+	register int i;
+	register struct ether_arp *ah;
+	register struct arp_list *al;
+	struct {
+		struct ether_header eh;
+		struct {
+			struct ether_arp arp;
+			u_char pad[18]; 	/* 60 - sizeof(...) */
+		} data;
+	} wbuf;
+	struct {
+		struct ether_header eh;
+		struct {
+			struct ether_arp arp;
+			u_char pad[24]; 	/* extra space */
+		} data;
+	} rbuf;
+
+	/* Try for cached answer first */
+	for (i = 0, al = arp_list; i < arp_num; ++i, ++al)
+		if (addr.s_addr == al->addr.s_addr)
+			return (al->ea);
+
+	/* Don't overflow cache */
+	if (arp_num > ARP_NUM - 1) {
+		arp_num = 1;	/* recycle */
+		printf("arpwhohas: overflowed arp_list!\n");
+	}
+
+#ifdef ARP_DEBUG
+ 	if (debug)
+ 	    printf("arpwhohas: send request for %s\n", inet_ntoa(addr));
+#endif
+
+	bzero((char*)&wbuf.data, sizeof(wbuf.data));
+	ah = &wbuf.data.arp;
+	ah->arp_hrd = htons(ARPHRD_ETHER);
+	ah->arp_pro = htons(ETHERTYPE_IP);
+	ah->arp_hln = sizeof(ah->arp_sha); /* hardware address length */
+	ah->arp_pln = sizeof(ah->arp_spa); /* protocol address length */
+	ah->arp_op = htons(ARPOP_REQUEST);
+	MACPY(d->myea, ah->arp_sha);
+	bcopy(&d->myip, ah->arp_spa, sizeof(ah->arp_spa));
+	/* Leave zeros in arp_tha */
+	bcopy(&addr, ah->arp_tpa, sizeof(ah->arp_tpa));
+
+	/* Store ip address in cache (incomplete entry). */
+	al->addr = addr;
+
+	i = sendrecv(d,
+	    arpsend, &wbuf.data, sizeof(wbuf.data),
+	    arprecv, &rbuf.data, sizeof(rbuf.data));
+	if (i == -1) {
+		panic("arp: no response for %s\n",
+			  inet_ntoa(addr));
+	}
+
+	/* Store ethernet address in cache */
+	ah = &rbuf.data.arp;
+#ifdef ARP_DEBUG
+ 	if (debug) {
+		printf("arp: response from %s\n",
+		    ether_sprintf(rbuf.eh.ether_shost));
+		printf("arp: cacheing %s --> %s\n",
+		    inet_ntoa(addr), ether_sprintf(ah->arp_sha));
+	}
+#endif
+	MACPY(ah->arp_sha, al->ea);
+	++arp_num;
+
+	return (al->ea);
+}
+
+static ssize_t
+arpsend(d, pkt, len)
+	register struct iodesc *d;
+	register void *pkt;
+	register size_t len;
+{
+
+#ifdef ARP_DEBUG
+ 	if (debug)
+		printf("arpsend: called\n");
+#endif
+
+	return (sendether(d, pkt, len, bcea, ETHERTYPE_ARP));
+}
+
+/*
+ * Returns 0 if this is the packet we're waiting for
+ * else -1 (and errno == 0)
+ */
+static ssize_t
+arprecv(d, pkt, len, tleft)
+	register struct iodesc *d;
+	register void *pkt;
+	register size_t len;
+	time_t tleft;
+{
+	register ssize_t n;
+	register struct ether_arp *ah;
+	u_int16_t etype;	/* host order */
+
+#ifdef ARP_DEBUG
+ 	if (debug)
+		printf("arprecv: ");
+#endif
+
+	n = readether(d, pkt, len, tleft, &etype);
+	errno = 0;	/* XXX */
+	if (n == -1 || n < sizeof(struct ether_arp)) {
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("bad len=%d\n", n);
+#endif
+		return (-1);
+	}
+
+	if (etype != ETHERTYPE_ARP) {
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("not arp type=%d\n", etype);
+#endif
+		return (-1);
+	}
+
+	/* Ethernet address now checked in readether() */
+
+	ah = (struct ether_arp *)pkt;
+	if (ah->arp_hrd != htons(ARPHRD_ETHER) ||
+	    ah->arp_pro != htons(ETHERTYPE_IP) ||
+	    ah->arp_hln != sizeof(ah->arp_sha) ||
+	    ah->arp_pln != sizeof(ah->arp_spa) )
+	{
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("bad hrd/pro/hln/pln\n");
+#endif
+		return (-1);
+	}
+
+	if (ah->arp_op == htons(ARPOP_REQUEST)) {
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("is request\n");
+#endif
+		arp_reply(d, ah);
+		return (-1);
+	}
+
+	if (ah->arp_op != htons(ARPOP_REPLY)) {
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("not ARP reply\n");
+#endif
+		return (-1);
+	}
+
+	/* Is the reply from the source we want? */
+	if (bcmp(&arp_list[arp_num].addr,
+			 ah->arp_spa, sizeof(ah->arp_spa)))
+	{
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("unwanted address\n");
+#endif
+		return (-1);
+	}
+	/* We don't care who the reply was sent to. */
+
+	/* We have our answer. */
+#ifdef ARP_DEBUG
+ 	if (debug)
+		printf("got it\n");
+#endif
+	return (n);
+}
+
+/*
+ * Convert an ARP request into a reply and send it.
+ * Notes:  Re-uses buffer.  Pad to length = 46.
+ */
+void
+arp_reply(d, pkt)
+	register struct iodesc *d;
+	register void *pkt;		/* the request */
+{
+	struct ether_arp *arp = pkt;
+
+	if (arp->arp_hrd != htons(ARPHRD_ETHER) ||
+	    arp->arp_pro != htons(ETHERTYPE_IP) ||
+	    arp->arp_hln != sizeof(arp->arp_sha) ||
+	    arp->arp_pln != sizeof(arp->arp_spa) )
+	{
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("arp_reply: bad hrd/pro/hln/pln\n");
+#endif
+		return;
+	}
+
+	if (arp->arp_op != htons(ARPOP_REQUEST)) {
+#ifdef ARP_DEBUG
+		if (debug)
+			printf("arp_reply: not request!\n");
+#endif
+		return;
+	}
+
+	/* If we are not the target, ignore the request. */
+	if (bcmp(arp->arp_tpa, &d->myip, sizeof(arp->arp_tpa)))
+		return;
+
+#ifdef ARP_DEBUG
+	if (debug) {
+		printf("arp_reply: to %s\n", ether_sprintf(arp->arp_sha));
+	}
+#endif
+
+	arp->arp_op = htons(ARPOP_REPLY);
+	/* source becomes target */
+	bcopy(arp->arp_sha, arp->arp_tha, sizeof(arp->arp_tha));
+	bcopy(arp->arp_spa, arp->arp_tpa, sizeof(arp->arp_tpa));
+	/* here becomes source */
+	bcopy(d->myea,  arp->arp_sha, sizeof(arp->arp_sha));
+	bcopy(&d->myip, arp->arp_spa, sizeof(arp->arp_spa));
+
+	/*
+	 * No need to get fancy here.  If the send fails, the
+	 * requestor will just ask again.
+	 */
+	(void) sendether(d, pkt, sizeof(*arp) + 18,
+	                 arp->arp_tha, ETHERTYPE_ARP);
+}