#!/usr/bin/env bash

tmp_err_msg=$(mktemp)

# -------------
# --- Some functions
# -------------
clean_up() {

   # Perform program exit housekeeping
   rm -f $tmp_err_msg
   exit $1
}

echononl(){
   echo X\\c > /tmp/shprompt$$
   if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
      echo -e -n "$*\\c" 1>&2
   else
       echo -e -n "$*" 1>&2
   fi
   rm /tmp/shprompt$$
}

fatal(){
   echo ""
   echo -e "fatal error: $*"
   echo ""
   echo -e "\t\033[31m\033[1mInstalllation will be interrupted\033[m\033[m"
   echo ""
   exit 1
}

error(){
   echo ""
   echo -e "\t[ \033[31m\033[1mFehler\033[m ]: $*"
   echo ""
}

warn (){
   echo ""
   echo -e "\t[ \033[33m\033[1mWarning\033[m ]: $*"
   echo ""
}

info (){
   echo ""
   echo -e "\t[ \033[32m\033[1mInfo\033[m ]: $*"
   echo ""
}

echo_done() {
   echo -e "\033[80G[ \033[32mdone\033[m ]"
}
echo_ok() {
   echo -e "\033[80G[ \033[32mok\033[m ]"
}
echo_warning() {
   echo -e "\033[80G[ \033[33m\033[1mwarn\033[m ]"
}
echo_failed(){
   echo -e "\033[80G[ \033[1;31mfailed\033[m ]"
}
echo_skipped() {
   echo -e "\033[80G[ \033[33m\033[1mskipped\033[m ]"
}

## - Install Postfix Firewall Daemon from debian packages system
## -
echononl "   Install Postfix Firewall Daemon from debian packages system"
_pkg="postfwd"
if aptitude search $_pkg | grep " $_pkg " | grep -e "^i" > /dev/null 2>&1 ; then
   echo_skipped
else
   DEBIAN_FRONTEND=noninteractive apt-get -y install $_pkg > /dev/null 2> $tmp_err_msg
   if [[ $? -eq 0 ]] ; then
      echo_ok
   else
      echo_failed
      error "$(cat $tmp_err_msg)"
   fi
fi

echononl "   Adjust /etc/default/postfwd"
perl -i -n -p -e "s#^(\s*)(STARTUP=.*)#\#\1\2\nSTARTUP=1#" \
   /etc/default/postfwd > $tmp_err_msg 2>&1
if [[ $? -eq 0 ]] ; then
   echo_ok
else
   echo_failed
   error "$(cat $tmp_err_msg)"
fi

_file="/etc/postfix/postfwd.wl-user"
echononl "   Create whitelist file '$_file' for postfwd"
if [[ ! -f "$_file" ]]; then
	cat << EOF > "$_file"
# ---
# SASL Users whitelisted by postfwd
# ---

EOF
	if [[ $? -eq 0 ]] ; then
		echo_ok
	else
		echo_failed
	fi
else
	echo_skipped
fi

_file="/etc/postfix/postfwd.bl-user"
echononl "   Create whitelist file '$_file' for postfwd"
if [[ ! -f "$_file" ]]; then
	cat << EOF > "$_file"
# ---
# SASL Users blocked by postfwd
# ---

EOF
	if [[ $? -eq 0 ]] ; then
		echo_ok
	else
		echo_failed
	fi
else
	echo_skipped
fi

_file="/etc/postfix/postfwd.bl-sender"
echononl "   Create whitelist file '$_file' for postfwd"
if [[ ! -f "$_file" ]]; then
	cat << EOF > "$_file"
# ---
# Sender addresses blocked by postfwd
# ---

EOF
	if [[ $? -eq 0 ]] ; then
		echo_ok
	else
		echo_failed
	fi
else
	echo_skipped
fi

echononl "   Create configuration file '/etc/postfix/postfwd.cf'.."
if [[ ! -f "/etc/postfix/postfwd.cf" ]]; then
	cat << EOF > /etc/postfix/postfwd.cf

#======= Definitions ============

# Match messages with an associated SASL username
&&SASL_AUTH {
    sasl_username!~^\$
}

# Whitelist users
&&TRUSTED_USERS {
    sasl_username==file:/etc/postfix/postfwd.wl-user
}

# Blacklist users
&&BLOCK_USERS {
   sasl_username==file:/etc/postfix/postfwd.bl-user
}

# Blacklist sender adresses
&&BLOCK_SENDER {
   sender==file:/etc/postfix/postfwd.bl-sender
}

# Inbound emails only
&&INCOMING {
    client_address!=127.0.0.1
}


#======= Rule Sets ============

# Whitelists

# Whitelist sasl users
id=WHL_USERS
	&&TRUSTED_USERS
	action=DUNNO


# Blacklist users

id=BL_USERS
   &&BLOCK_USERS
   action=REJECT User is blocked by so36.NET admins. Error: BL_USERS

# Blacklist sender
#
#    Claim successful delivery and silently discard the message.
#
id=BL_SENDER
   &&BLOCK_SENDER
   action=DISCARD
   #action=REJECT Sender address is blocked by so36.NET admins. Error: BL_SENDER


# Rate Limits

# Block messages with more than 50 recipients
id=BLOCK_MSG_RCPT
    &&INCOMING
    &&SASL_AUTH
	 recipient_count=50
    action=REJECT Too many recipients, please reduce to less than 50 or consider using a mailing list. Error: BLOCK_MSG_RCPT

# Block users sending more than 50 messages/hour
id=RATE_MSG
    &&INCOMING
    &&SASL_AUTH
    action=rate(\$\$sasl_username/50/3600/450 4.7.1 Number messages per hour exceeded. Error:RATE_MSG)

# Block users sending more than 250 recipients total/hour
id=RATE_RCPT
    &&INCOMING
    &&SASL_AUTH
    action=rcpt(\$\$sasl_username/250/3600/450 4.7.1 Number recipients per hour exceeded. Error:RATE_RCPT)

EOF
	if [[ $? -eq 0 ]] ; then
		echo_ok
	else
		echo_failed
	fi
else
	echo_skipped
fi

echononl "   Restart Postfix firewall daemon 'postfwd'.."
if $systemd_exists ; then
   systemctl restart postfwd > /dev/null 2> $tmp_err_msg
   if [[ $? -eq 0 ]] ; then
      echo_ok
   else
      echo_failed
      error "$(cat $tmp_err_msg)"
   fi
else
   /etc/init.d/postfwd restart > /dev/null 2> $tmp_err_msg
   if [[ $? -eq 0 ]] ; then
      echo_ok
   else
      echo_failed
      error "$(cat $tmp_err_msg)"
   fi
fi


warn "Postfix firewall daemin  is installed, but not integrated in postfix mailsystem (/etc/postfix/main.cf)"



clean_up 0