opendkim: Initial version of role

roles/opendkim/files/keystore.Makefile

@@ -0,0 +1,28 @@
+TARGETS := $(shell { \
+  if [ $$(date +%m) -lt 6 ]; then \
+    echo "$$(date +%Y)0101.key $$(date +%Y)0601.key" ; \
+  else \
+    echo "$$(date +%Y)0601.key $$(($$(date +%Y) + 1))0101.key" ; \
+  fi \
+  })
+
+all: $(TARGETS)
+
+%.key:
+	@set -eu ; \
+	openssl genrsa -out "$@" 2048 ; \
+	chgrp opendkim "$@" ; \
+	chmod 0640 "$@" ; \
+	echo ; \
+	data="$$(printf "v=DKIM1; k=rsa; p=%s" \
+	  "$$(openssl rsa -in "$@" -pubout -outform der 2>/dev/null | openssl base64 -A)")" ; \
+	pos=0 ; \
+	printf "%s._domainkey\tIN\tTXT\t" "$$(echo "$@" | cut -d. -f1)" ; \
+	while true ; do \
+	  printf "\"%s\"" \
+	    "$$(echo "$$data" | cut -c $$((pos + 1))-$$((pos + 254)))" ; \
+	  pos="$$((pos + 254))" ; \
+	  [ $${#data} -gt $$pos ] || break ; \
+	  printf " " ; \
+	done ; \
+	echo