193 lines
3.3 KiB
C
193 lines
3.3 KiB
C
#include <u.h>
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#include <libc.h>
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#include <bio.h>
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#include <ip.h>
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#include <ndb.h>
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#include "arp.h"
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typedef struct Rarp Rarp;
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struct Rarp
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{
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uchar edst[6];
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uchar esrc[6];
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uchar type[2];
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uchar hrd[2];
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uchar pro[2];
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uchar hln;
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uchar pln;
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uchar op[2];
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uchar sha[6];
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uchar spa[4];
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uchar tha[6];
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uchar tpa[4];
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};
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uchar myip[IPaddrlen];
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uchar myether[6];
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char rlog[] = "ipboot";
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char *device = "ether0";
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int debug;
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Ndb *db;
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char* lookup(char*, char*, char*, char*, int);
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void
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error(char *s)
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{
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syslog(1, rlog, "error %s: %r", s);
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exits(s);
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}
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char net[32];
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void
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usage(void)
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{
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fprint(2, "usage: %s [-e device] [-x netmtpt] [-f ndb-file] [-d]\n", argv0);
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exits("usage");
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}
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void
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main(int argc, char *argv[])
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{
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int edata, ectl;
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uchar buf[2048];
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long n;
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Rarp *rp;
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char ebuf[16];
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char ipbuf[64];
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char file[128];
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int arp;
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char *p, *ndbfile;
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ndbfile = nil;
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setnetmtpt(net, sizeof(net), nil);
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ARGBEGIN{
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case 'e':
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p = ARGF();
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if(p == nil)
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usage();
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device = p;
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break;
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case 'd':
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debug = 1;
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break;
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case 'f':
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p = ARGF();
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if(p == nil)
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usage();
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ndbfile = p;
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break;
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case 'x':
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p = ARGF();
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if(p == nil)
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usage();
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setnetmtpt(net, sizeof(net), p);
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break;
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}ARGEND
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USED(argc, argv);
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fmtinstall('E', eipfmt);
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fmtinstall('I', eipfmt);
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fmtinstall('V', eipfmt);
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db = ndbopen(ndbfile);
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if(db == 0)
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error("can't open the database");
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edata = dial(netmkaddr("0x8035", device, 0), 0, 0, &ectl);
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if(edata < 0)
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error("can't open ethernet");
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if(myipaddr(myip, net) < 0)
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error("can't get my ip address");
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sprint(ebuf, "%s/%s", net, device);
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if(myetheraddr(myether, ebuf) < 0)
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error("can't get my ether address");
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snprint(file, sizeof(file), "%s/arp", net);
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if((arp = open(file, ORDWR)) < 0)
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fprint(2, "rarpd: can't open %s\n", file);
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switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
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case -1:
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error("fork");
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case 0:
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break;
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default:
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exits(0);
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}
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for(;;){
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n = read(edata, buf, sizeof(buf));
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if(n <= 0)
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error("reading");
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if(n < sizeof(Rarp)){
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syslog(debug, rlog, "bad packet size %ld", n);
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continue;
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}
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rp = (Rarp*)buf;
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if(rp->op[0]!=0 && rp->op[1]!=3){
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syslog(debug, rlog, "bad op %d %d %E",
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rp->op[1], rp->op[0], rp->esrc);
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continue;
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}
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if(debug)
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syslog(debug, rlog, "rcv se %E si %V te %E ti %V",
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rp->sha, rp->spa, rp->tha, rp->tpa);
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sprint(ebuf, "%E", rp->tha);
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if(lookup("ether", ebuf, "ip", ipbuf, sizeof ipbuf) == nil){
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syslog(debug, rlog, "client lookup failed: %s", ebuf);
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continue;
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}
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v4parseip(rp->tpa, ipbuf);
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memmove(rp->sha, myether, sizeof(rp->sha));
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v6tov4(rp->spa, myip);
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rp->op[0] = 0;
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rp->op[1] = 4;
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memmove(rp->edst, rp->esrc, sizeof(rp->edst));
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if(debug)
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syslog(debug, rlog, "send se %E si %V te %E ti %V",
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rp->sha, rp->spa, rp->tha, rp->tpa);
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if(write(edata, buf, 60) != 60)
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error("write failed");
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if(arp < 0)
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continue;
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if(fprint(arp, "add %E %V", rp->esrc, rp->tpa) < 0)
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fprint(2, "can't write arp entry\n");
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}
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}
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char*
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lookup(char *sattr, char *sval, char *tattr, char *tval, int len)
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{
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static Ndb *db;
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char *attrs[1];
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Ndbtuple *t;
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if(db == nil)
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db = ndbopen(0);
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if(db == nil)
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return nil;
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if(sattr == nil)
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sattr = ipattr(sval);
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attrs[0] = tattr;
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t = ndbipinfo(db, sattr, sval, attrs, 1);
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if(t == nil)
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return nil;
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strncpy(tval, t->val, len);
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tval[len-1] = 0;
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ndbfree(t);
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return tval;
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}
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