138 lines
2.7 KiB
C
138 lines
2.7 KiB
C
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <netinet/in_systm.h>
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#include <errno.h>
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#include <string.h>
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#include "stand.h"
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#include "net.h"
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#include "netif.h"
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static int rarpsend(struct iodesc *, void *, int);
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static int rarprecv(struct iodesc *, void *, int);
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/*
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* Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
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*/
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n_long
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rarp_getipaddress(sock)
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int sock;
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{
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struct iodesc *d;
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register struct ether_arp *ap;
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register void *pkt;
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struct {
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u_char header[HEADER_SIZE];
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struct ether_arp wrarp;
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} wbuf;
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union {
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u_char buffer[RECV_SIZE];
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struct {
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u_char header[HEADER_SIZE];
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struct ether_arp xrrarp;
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}xrbuf;
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#define rrarp xrbuf.xrrarp
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} rbuf;
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarp: socket=%d\n", sock);
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#endif
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if (!(d = socktodesc(sock))) {
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printf("rarp: bad socket. %d\n", sock);
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return(INADDR_ANY);
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}
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarp: d=%x\n", (u_int)d);
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#endif
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ap = &wbuf.wrarp;
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pkt = &rbuf.rrarp;
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pkt -= HEADER_SIZE;
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bzero(ap, sizeof(*ap));
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ap->arp_hrd = htons(ARPHRD_ETHER);
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ap->arp_pro = htons(ETHERTYPE_IP);
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ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
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ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
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ap->arp_op = htons(REVARP_REQUEST);
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bcopy(d->myea, ap->arp_sha, 6);
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bcopy(d->myea, ap->arp_tha, 6);
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if (sendrecv(d,
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rarpsend, ap, sizeof(*ap),
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rarprecv, pkt, RECV_SIZE) < 0) {
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printf("No response for RARP request\n");
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return(INADDR_ANY);
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}
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return(myip);
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}
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/*
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* Broadcast a RARP request (i.e. who knows who I am)
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*/
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static int
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rarpsend(d, pkt, len)
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register struct iodesc *d;
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register void *pkt;
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register int len;
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{
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarpsend: called\n");
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#endif
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return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
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}
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/*
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* Called when packet containing RARP is received
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*/
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static int
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rarprecv(d, pkt, len)
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register struct iodesc *d;
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register void *pkt;
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register int len;
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{
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register struct ether_header *ep;
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register struct ether_arp *ap;
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarprecv: called\n");
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#endif
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if (len < sizeof(struct ether_header) + sizeof(struct ether_arp)) {
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errno = 0;
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return (-1);
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}
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ep = (struct ether_header *)pkt;
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if (ntohs(ep->ether_type) != ETHERTYPE_REVARP) {
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errno = 0;
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return (-1);
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}
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ap = (struct ether_arp *)(ep + 1);
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if (ntohs(ap->arp_op) != REVARP_REPLY ||
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ntohs(ap->arp_pro) != ETHERTYPE_IP) {
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errno = 0;
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return (-1);
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}
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if (bcmp(ap->arp_tha, d->myea, 6)) {
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errno = 0;
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return (-1);
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}
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bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip));
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bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip));
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return(0);
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}
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