ip/dhcp6d: ignore short and from non-local source packets

diff --git a/sys/src/cmd/ip/dhcp6d.c b/sys/src/cmd/ip/dhcp6d.c
index 96e104fa7d62caff27d71f3f5bdd6cd93f175dcd..a130daed6fb9cfa61e5b6ca8b435d7411414d235 100644 (file)
--- a/sys/src/cmd/ip/dhcp6d.c
+++ b/sys/src/cmd/ip/dhcp6d.c
@@ -113,6 +113,21 @@ findifc(char *net, uchar ip[IPaddrlen])
        return nil;
 }
 
+static Iplifc*
+localonifc(Ipifc *ifc, uchar ip[IPaddrlen])
+{
+       Iplifc *lifc;
+       uchar net[IPaddrlen];
+
+       for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){
+               maskip(ip, lifc->mask, net);
+               if(ipcmp(net, lifc->net) == 0)
+                       return lifc;
+       }
+
+       return nil;
+}
+
 static int
 openlisten(char *net)
 {
@@ -310,21 +325,27 @@ main(int argc, char *argv[])
                break;
        }
 
-       while((n = read(fd, ibuf, sizeof(ibuf))) > Udphdrsize+4){
-               r->req.p = ibuf+Udphdrsize;
-               r->req.e = ibuf+n;
+       while((n = read(fd, ibuf, sizeof(ibuf))) > 0){
+               if(n < Udphdrsize+4)
+                       continue;
+
+               r->udp = (Udphdr*)ibuf;
+               if(isv4(r->udp->raddr))
+                       continue;
+               if((r->ifc = findifc(netmtpt, r->udp->ifcaddr)) == nil)
+                       continue;
+               if(localonifc(r->ifc, r->udp->raddr) == nil)
+                       continue;
 
                memmove(obuf, ibuf, Udphdrsize);
-               r->udp = (Udphdr*)obuf;
+               r->req.p = ibuf+Udphdrsize;
+               r->req.e = ibuf+n;
                r->resp.p = obuf+Udphdrsize;
                r->resp.e = &obuf[sizeof(obuf)];
 
                r->tra = r->req.p[1]<<16 | r->req.p[2]<<8 | r->req.p[3];
                r->req.t = r->req.p[0];
 
-               if((r->ifc = findifc(netmtpt, r->udp->ifcaddr)) == nil)
-                       continue;
-
                if(debug)
                fprint(2, "%I->%I(%s) typ=%d tra=%x\n",
                        r->udp->raddr, r->udp->laddr, r->ifc->dev,