sys/src/cmd/ip/rarpd.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <bio.h>
   4 #include <ip.h>
   5 #include <ndb.h>
   6 #include "arp.h"
   7
   8 typedef struct Rarp     Rarp;
   9
  10 struct Rarp
  11 {
  12         uchar   edst[6];
  13         uchar   esrc[6];
  14         uchar   type[2];
  15         uchar   hrd[2];
  16         uchar   pro[2];
  17         uchar   hln;
  18         uchar   pln;
  19         uchar   op[2];
  20         uchar   sha[6];
  21         uchar   spa[4];
  22         uchar   tha[6];
  23         uchar   tpa[4];
  24 };
  25
  26 uchar   myip[IPaddrlen];
  27 uchar   myether[6];
  28 char    rlog[] = "ipboot";
  29 char    *device = "ether0";
  30 int     debug;
  31 Ndb     *db;
  32
  33 char*   lookup(char*, char*, char*, char*, int);
  34
  35 void
  36 error(char *s)
  37 {
  38         syslog(1, rlog, "error %s: %r", s);
  39         exits(s);
  40 }
  41
  42 char net[32];
  43
  44 void
  45 usage(void)
  46 {
  47         fprint(2, "usage: %s [-e device] [-x netmtpt] [-f ndb-file] [-d]\n", argv0);
  48         exits("usage");
  49 }
  50
  51 void
  52 main(int argc, char *argv[])
  53 {
  54         int edata, ectl;
  55         uchar buf[2048];
  56         long n;
  57         Rarp *rp;
  58         char ebuf[16];
  59         char ipbuf[64];
  60         char file[128];
  61         int arp;
  62         char *p, *ndbfile;
  63
  64         ndbfile = nil;
  65         setnetmtpt(net, sizeof(net), nil);
  66         ARGBEGIN{
  67         case 'e':
  68                 p = ARGF();
  69                 if(p == nil)
  70                         usage();
  71                 device = p;
  72                 break;
  73         case 'd':
  74                 debug = 1;
  75                 break;
  76         case 'f':
  77                 p = ARGF();
  78                 if(p == nil)
  79                         usage();
  80                 ndbfile = p;
  81                 break;
  82         case 'x':
  83                 p = ARGF();
  84                 if(p == nil)
  85                         usage();
  86                 setnetmtpt(net, sizeof(net), p);
  87                 break;
  88         }ARGEND
  89         USED(argc, argv);
  90
  91         fmtinstall('E', eipfmt);
  92         fmtinstall('I', eipfmt);
  93         fmtinstall('V', eipfmt);
  94
  95         db = ndbopen(ndbfile);
  96         if(db == 0)
  97                 error("can't open the database");
  98
  99         edata = dial(netmkaddr("0x8035", device, 0), 0, 0, &ectl);
 100         if(edata < 0)
 101                 error("can't open ethernet");
 102
 103         if(myipaddr(myip, net) < 0)
 104                 error("can't get my ip address");
 105         sprint(ebuf, "%s/%s", net, device);
 106         if(myetheraddr(myether, ebuf) < 0)
 107                 error("can't get my ether address");
 108
 109         snprint(file, sizeof(file), "%s/arp", net);
 110         if((arp = open(file, ORDWR)) < 0)
 111                 fprint(2, "rarpd: can't open %s\n", file);
 112
 113         switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
 114         case -1:
 115                 error("fork");
 116         case 0:
 117                 break;
 118         default:
 119                 exits(0);
 120         }
 121
 122         for(;;){
 123                 n = read(edata, buf, sizeof(buf));
 124                 if(n <= 0)
 125                         error("reading");
 126                 if(n < sizeof(Rarp)){
 127                         syslog(debug, rlog, "bad packet size %ld", n);
 128                         continue;
 129                 }
 130                 rp = (Rarp*)buf;
 131                 if(rp->op[0]!=0 && rp->op[1]!=3){
 132                         syslog(debug, rlog, "bad op %d %d %E",
 133                                 rp->op[1], rp->op[0], rp->esrc);
 134                         continue;
 135                 }
 136
 137                 if(debug)
 138                         syslog(debug, rlog, "rcv se %E si %V te %E ti %V",
 139                                  rp->sha, rp->spa, rp->tha, rp->tpa);
 140
 141                 sprint(ebuf, "%E", rp->tha);
 142                 if(lookup("ether", ebuf, "ip", ipbuf, sizeof ipbuf) == nil){
 143                         syslog(debug, rlog, "client lookup failed: %s", ebuf);
 144                         continue;
 145                 }
 146                 v4parseip(rp->tpa, ipbuf);
 147
 148                 memmove(rp->sha, myether, sizeof(rp->sha));
 149                 v6tov4(rp->spa, myip);
 150
 151                 rp->op[0] = 0;
 152                 rp->op[1] = 4;
 153                 memmove(rp->edst, rp->esrc, sizeof(rp->edst));
 154
 155                 if(debug)
 156                         syslog(debug, rlog, "send se %E si %V te %E ti %V",
 157                                  rp->sha, rp->spa, rp->tha, rp->tpa);
 158
 159                 if(write(edata, buf, 60) != 60)
 160                         error("write failed");
 161
 162                 if(arp < 0)
 163                         continue;
 164                 if(fprint(arp, "add %E %V", rp->esrc, rp->tpa) < 0)
 165                         fprint(2, "can't write arp entry\n");
 166         }
 167 }
 168
 169 char*
 170 lookup(char *sattr, char *sval, char *tattr, char *tval, int len)
 171 {
 172         static Ndb *db;
 173         char *attrs[1];
 174         Ndbtuple *t;
 175
 176         if(db == nil)
 177                 db = ndbopen(0);
 178         if(db == nil)
 179                 return nil;
 180
 181         if(sattr == nil)
 182                 sattr = ipattr(sval);
 183
 184         attrs[0] = tattr;
 185         t = ndbipinfo(db, sattr, sval, attrs, 1);
 186         if(t == nil)
 187                 return nil;
 188         strncpy(tval, t->val, len);
 189         tval[len-1] = 0;
 190         ndbfree(t);
 191         return tval;
 192 }