make it easier to specify alternate DHCP ports

Update: also document the dhcpport= option in conf.d/ltsp

=== modified file 'conf.d/ltsp'
--- conf.d/ltsp 2008-03-04 12:35:43 +0000
+++ conf.d/ltsp 2008-03-04 13:38:08 +0000
@@ -1,2 +1,14 @@
 MODULES="netboot"
 BOOT="ltsp_nbd"
+
+# DHCPPORT: tell ipconfig from klibc-utils) to use an alternate DHCP port
+# Default: 68
+# example: if you want to use alternate DHCP ports, use something like
+# DHCPPORT="1068"
+# this variable can be overridden using the dhcpport= boot option
+# Your DHCP server will have to listen on $DHCPPORT - 1
+# Note: for alternate DHCP ports, see
+# http://<email address hidden>/msg31182.html
+# That mail might be a bit outdated but it still gives a nice overview
+# DHCPPORT=""
+

=== modified file 'scripts/ltsp_nbd'
--- scripts/ltsp_nbd 2008-03-04 12:35:43 +0000
+++ scripts/ltsp_nbd 2008-03-04 13:24:15 +0000
@@ -7,6 +7,14 @@
        run_scripts /scripts/nfs-top
        [ "$quiet" != "y" ] && log_end_msg

+ if [ -n "$dhcpport" ]; then
+ DHCPPORT="$dhcpport"
+ fi
+
+ if [ -n "$DHCPPORT" ]; then
+ IPCONFIGARGS="-p $DHCPPORT $IPCONFIGARGS"
+ fi
+
        # For DHCP
        modprobe -q af_packet

@@ -16,13 +24,13 @@
                        ;;
                ""|on|any)
                        # Bring up device
- ipconfig ${DEVICE}
+ ipconfig ${DEVICE} $IPCONFIGARGS
                        ;;
                dhcp|bootp|rarp|both)
- ipconfig -c ${IPOPTS} -d ${DEVICE}
+ ipconfig -c ${IPOPTS} -d ${DEVICE} $IPCONFIGARGS
                        ;;
                *)
- ipconfig -d $IPOPTS
+ ipconfig -d $IPOPTS $IPCONFIGARGS

                        # grab device entry from ip option
                        NEW_DEVICE=${IPOPTS#*:*:*:*:*:*}

Oliver Grawert knows how to make things simpler.
You probably want to make sure that the indentation is correct, I'm probably incapable of configuring my editor correctly.

=== modified file 'conf.d/ltsp'
--- conf.d/ltsp 2008-03-04 12:35:43 +0000
+++ conf.d/ltsp 2008-03-04 13:38:08 +0000
@@ -1,2 +1,14 @@
 MODULES="netboot"
 BOOT="ltsp_nbd"
+
+# DHCPPORT: tell ipconfig from klibc-utils) to use an alternate DHCP port
+# Default: 68
+# example: if you want to use alternate DHCP ports, use something like
+# DHCPPORT="1068"
+# this variable can be overridden using the dhcpport= boot option
+# Your DHCP server will have to listen on $DHCPPORT - 1
+# Note: for alternate DHCP ports, see
+# http://<email address hidden>/msg31182.html
+# That mail might be a bit outdated but it still gives a nice overview
+# DHCPPORT=""
+

=== modified file 'scripts/ltsp_nbd'
--- scripts/ltsp_nbd 2008-03-04 12:35:43 +0000
+++ scripts/ltsp_nbd 2008-03-04 14:16:02 +0000
@@ -7,6 +7,10 @@
        run_scripts /scripts/nfs-top
        [ "$quiet" != "y" ] && log_end_msg

+ if [ -n "$dhcpport" ]; then
+ DHCPPORT="$dhcpport"
+ fi
+
        # For DHCP
        modprobe -q af_packet

@@ -19,6 +23,9 @@
                        ipconfig ${DEVICE}
                        ;;
                dhcp|bootp|rarp|both)
+ if [ ${IPOPTS} == "dhcp"] && [ -n "$DHCPPORT" ]; then
+ IPOPTS="${IPOPTS} -p ${DHCPPORT}"
+ fi
                        ipconfig -c ${IPOPTS} -d ${DEVICE}
                        ;;
                *)

This bug was fixed in the package ltsp - 5.0.40~bzr20080212-0ubuntu4

---------------
ltsp (5.0.40~bzr20080212-0ubuntu4) hardy; urgency=low

  * make sure the right proxy line is set in the chroot, thanks
    to stephane graber for that fix (LP: #213927)
  * make acpid [ i386 amd64 ] only dependency, since its not not available on ppc
    (LP: #213014, LP: #199747)
  * fix configure-x.sh interpreter line (LP: #196706)
  * make sure resolv.conf is available in the chroot (LP: #72482)
  * merge fix for dhcp port handling, thanks to Michael Haas, (LP: #198356)
  * we only tell users with nfs-kernel-server installed that they need to
    update /etc/exports (LP: #198915)
  * fix kiosk plugin to use the right package names (LP: #163278, LP: #212738)
  * fix hardcoded path in ltsp-update-image and quiten down noisy rm commands
    (LP: #198157)
  * make sure the ltsp-update-* scripts operate on symlinked dirs (LP: #151503)
  * add final updates for mythbuntu plugin and drop accidentially included
    patch file from debian/extra-plugins (LP: #212550)

 -- Oliver Grawert <email address hidden> Tue, 08 Apr 2008 15:03:51 +0200

This is NOT fixed yet (Hardy 8.04). Excuse my very rushed comment.

First, a typo

- if [ ${IPOPTS} == "dhcp"] && [ -n "$DHCPPORT" ]; then
+ if [ ${IPOPTS} == "dhcp" ] && [ -n "$DHCPPORT" ]; then

(Note the space)

Second. I'm still unsure if $IPOPTS should be in ipconfig long format as described here: -
  - http://codtech.com/wiki/index.php/Ipconfig#interface_spec_long_form

Or if it is something more simpler (ie kernel command line 'ip=dhcp'). Or is it both?
If I pass the following kernel command line:
  ip=172.16.200.100:172.16.200.1:::::none
the client gets assigned a static IP correctly.

If I pass: -
  ip=:172.16.200.1:::::dhcp

the script fails as its expecting 'dhcp' as its only parameter (${IPOPTS} == "dhcp").

Has this bug been reintroduced to jaunty? Neither the "dhcpport" boot param nor the setting in /usr/share/initramfs-tools/conf.d/ltsp (in the chroot) seem to have any effect. I can get an alternate dhcp port by explicitly tacking "-p 1068" onto the ipconfig command in /usr/share/initramfs-tools/scripts/functions, but as far as I can tell there is no "cleaner" way to set this.

gpxe (etherboot) also dropped support for alternate DHCP ports.
An alternative method: https://help.ubuntu.com/community/UbuntuLTSP/ProxyDHCP
In my case this was even better than changing the DHCP ports, because the proxy dhcp method also works with standard PXE clients.