[9fans] [PATCH 2/3] Send vendor ndb attribute if available

[k0ga]

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;