diff options
Diffstat (limited to 'usr/src/boot/lib/libstand/arp.c')
| -rw-r--r-- | usr/src/boot/lib/libstand/arp.c | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/usr/src/boot/lib/libstand/arp.c b/usr/src/boot/lib/libstand/arp.c new file mode 100644 index 0000000000..e6175325f3 --- /dev/null +++ b/usr/src/boot/lib/libstand/arp.c @@ -0,0 +1,309 @@ +/* $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. + * 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/cdefs.h> +__FBSDID("$FreeBSD$"); + +#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) + struct iodesc *d; + struct in_addr addr; +{ + int i; + struct ether_arp *ah; + 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) + struct iodesc *d; + void *pkt; + 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) + struct iodesc *d; + void *pkt; + size_t len; + time_t tleft; +{ + ssize_t n; + 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) + struct iodesc *d; + 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); +} |