Generate specific dhclient.conf to coerce the ISP to offer the same IP

4 files changed, 85 insertions, 0 deletions

diff --git a/tasks/general.yml b/tasks/general.yml
index e9c1ef3..902d6c4 100644
--- a/tasks/general.yml
+++ b/tasks/general.yml
@@ -43,3 +43,18 @@
   service:
     name: auditd
     state: started
+
+- name: Set up crontab
+  template:
+    src: etc_crontab.j2
+    dest: /etc/crontab
+    owner: root
+    group: wheel
+    mode: "0644"
+  register: etc_crontab
+
+- name: Restart cron
+  service:
+    name: cron
+    state: restarted
+  when: etc_crontab.changed
diff --git a/tasks/network.yml b/tasks/network.yml
index 45f44e6..dbfa43c 100644
--- a/tasks/network.yml
+++ b/tasks/network.yml
@@ -142,3 +142,11 @@
     name: do_dyndns
     state: restarted
   when: not do_dyndns_start.changed and (do_dyndns_sh.changed or do_dyndns_rc.changed)
+
+- name: Install gen_dhclient_conf.sh
+  template:
+    src: usr_local_bin_gen_dhclient_conf.sh.j2
+    dest: /usr/local/bin/gen_dhclient_conf.sh
+    owner: root
+    group: wheel
+    mode: "0755"
diff --git a/templates/etc_crontab.j2 b/templates/etc_crontab.j2
new file mode 100644
index 0000000..cdd34a4
--- /dev/null
+++ b/templates/etc_crontab.j2
@@ -0,0 +1,24 @@
+# /etc/crontab - root's crontab for FreeBSD
+#
+#
+SHELL=/bin/sh
+PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin
+#
+#minute hour    mday    month   wday    who     command
+#
+# Save some entropy so that /dev/random can re-seed on boot.
+*/11    *       *       *       *       operator /usr/libexec/save-entropy
+#
+# Rotate log files every hour, if necessary.
+0       *       *       *       *       root    newsyslog
+#
+# Perform daily/weekly/monthly maintenance.
+1       3       *       *       *       root    periodic daily
+15      4       *       *       6       root    periodic weekly
+30      5       1       *       *       root    periodic monthly
+#
+# Adjust the time zone if the CMOS clock keeps local time, as opposed to
+# UTC time.  See adjkerntz(8) for details.
+1,31    0-5     *       *       *       root    adjkerntz -a
+# Generate /etc/dhclient.conf
+*/15    *       *       *       *       root    sh -c 'gen_dhclient_conf.sh | logger -t gen_dhclient_conf'
diff --git a/templates/usr_local_bin_gen_dhclient_conf.sh.j2 b/templates/usr_local_bin_gen_dhclient_conf.sh.j2
new file mode 100644
index 0000000..8c05f70
--- /dev/null
+++ b/templates/usr_local_bin_gen_dhclient_conf.sh.j2
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+set -eu
+
+IP=$(ifconfig wan0 | awk '/inet / {print $2}' | head -n1)
+HOSTNAME=$(hostname)
+CONFFILE=/etc/dhclient.conf
+NEWFILE=$(mktemp)
+if [ -f "${CONFFILE}" ]; then
+    OLDHASH=$(md5 -q "${CONFFILE}")
+else
+    OLDHASH="doesnotexist"
+fi
+
+cat <<EOF > "${NEWFILE}"
+# This file is generated by $0 periodically.
+# Changes will be overwritten.
+
+interface "wan0" {
+    send host-name "${HOSTNAME}";
+EOF
+
+if [ ! -z "$IP" ]; then
+cat <<EOF >> "${NEWFILE}"
+    send dhcp-requested-address $IP;
+EOF
+fi
+
+echo "}" >> "${NEWFILE}"
+
+mv "${NEWFILE}" "${CONFFILE}"
+
+# If changed, restart dhclient wan0
+md5 -c "${OLDHASH}" "${CONFFILE}" 1>/dev/null 2>/dev/null
+if [ ! "$?" = 0 ]; then
+    echo "Generated ${CONFFILE} has changed, restarting dhclient on wan0 (IP: ${IP})"
+    service dhclient restart wan0
+fi