At this moment plan9 is using vendorinfo to communicate some specific plan9 parameters, but there are some boards that use this attribute to set specific values. This patch allows netbooting of these boards using ndb attributes instead of hard coded solutions in dhcpd(1). Vendor attribute is used for that purpose because it is also used for the same purpose in bootp.
diff -r b1cb12e81f18 sys/src/cmd/ip/dhcpd/dhcpd.c --- a/sys/src/cmd/ip/dhcpd/dhcpd.c Sun Jan 20 12:55:31 2019 +0100 +++ b/sys/src/cmd/ip/dhcpd/dhcpd.c Tue Jan 22 18:06:01 2019 +0000 @@ -1277,8 +1277,7 @@ } - /* add plan9 specific options */ - if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0 - || strncmp((char*)rp->vendorclass, "p9-", 3) == 0){ + if (*rp->vendorclass != '\0') { /* point to temporary area */ op = rp->p; omax = rp->max; @@ -1286,15 +1285,21 @@ rp->p = vopts; rp->max = vopts + sizeof(vopts) - 1; - /* emit old v4 addresses first to make sure that they fit */ - addrsopt(rp, OP9fsv4, addrs, lookupserver("fs", addrs, nelem(addrs), t)); - addrsopt(rp, OP9authv4, addrs, lookupserver("auth", addrs, nelem(addrs), t)); + if (*rp->ii.vendor != '\0') + stringopt(rp, OBvendorinfo, rp->ii.vendor); - p9addrsopt(rp, OP9fs, addrs, lookupserver("fs", addrs, nelem(addrs), t)); - p9addrsopt(rp, OP9auth, addrs, lookupserver("auth", addrs, nelem(addrs), t)); - p9addrsopt(rp, OP9ipaddr, addrs, lookupserver("ip", addrs, nelem(addrs), t)); - p9addrsopt(rp, OP9ipmask, addrs, lookupserver("ipmask", addrs, nelem(addrs), t)); - p9addrsopt(rp, OP9ipgw, addrs, lookupserver("ipgw", addrs, nelem(addrs), t)); + /* add plan9 specific options */ + if (strncmp((char*)rp->vendorclass, "p9-", 3) == 0 + || strncmp((char*)rp->vendorclass, "plan9_", 6) == 0){ + /* emit old v4 addresses first to make sure that they fit */ + addrsopt(rp, OP9fsv4, addrs, lookupserver("fs", addrs, nelem(addrs), t)); + addrsopt(rp, OP9authv4, addrs, lookupserver("auth", addrs, nelem(addrs), t)); + + p9addrsopt(rp, OP9fs, addrs, lookupserver("fs", addrs, nelem(addrs), t)); + p9addrsopt(rp, OP9auth, addrs, lookupserver("auth", addrs, nelem(addrs), t)); + p9addrsopt(rp, OP9ipaddr, addrs, lookupserver("ip", addrs, nelem(addrs), t)); + p9addrsopt(rp, OP9ipmask, addrs, lookupserver("ipmask", addrs, nelem(addrs), t)); + p9addrsopt(rp, OP9ipgw, addrs, lookupserver("ipgw", addrs, nelem(addrs), t)); + } /* point back to packet, encapsulate vopts into packet */ j = rp->p - vopts;