Include a RFC 1533 "Maximum DHCP Message Size" option in our request.

ISC DHCP will limit the reply length to 64 bytes for bootp replies
unless we explicitly tell it we can do more.  We tell it that we can do
1200 bytes.

1 files changed, 17 insertions, 5 deletions

diff --git a/sys/nfs/bootp_subr.c b/sys/nfs/bootp_subr.c
index 3295248..d580c55 100644
--- a/sys/nfs/bootp_subr.c
+++ b/sys/nfs/bootp_subr.c
@@ -834,11 +834,23 @@ bootpc_init(void)
   call.xid = txdr_unsigned(xid);
   bcopy(LLADDR(sdl),&call.chaddr,sdl->sdl_alen);
   
-  call.vend[0]=99;
-  call.vend[1]=130;
-  call.vend[2]=83;
-  call.vend[3]=99;
-  call.vend[4]=255;
+  j = 0;
+  call.vend[j++]=99;
+  call.vend[j++]=130;
+  call.vend[j++]=83;
+  call.vend[j++]=99;
+
+  /*
+   * We send an RFC 1533 "Maximum DHCP Message Size" option, saying we
+   * can do 1200 bytes.  If we don't ISC DHCPD will limit the answer to
+   * 64 bytes and root/swap and similar will be dropped.
+   */
+  call.vend[j++]=57;
+  call.vend[j++]=2;
+  call.vend[j++]=(1200) % 256;
+  call.vend[j++]=(1200) / 256;
+
+  call.vend[j++]=255;
   
   call.secs = 0;
   call.flags = htons(0x8000); /* We need an broadcast answer */