1 files changed, 76 insertions, 0 deletions
diff --git a/modules/mkdir/iptables.nix b/modules/mkdir/iptables.nix
new file mode 100644
index 000000000..950aa8472
--- /dev/null
+++ b/modules/mkdir/iptables.nix
@@ -0,0 +1,76 @@
+{ config, pkgs, ... }:
+
+{
+  #
+  # iptables
+  #
+  networking.firewall.enable = false;
+  system.activationScripts.iptables =
+    let
+      log = false;
+      when = c: f: if c then f else "";
+    in
+      ''
+        ip4tables() { ${pkgs.iptables}/sbin/iptables "$@"; }
+        ip6tables() { ${pkgs.iptables}/sbin/ip6tables "$@"; }
+        ipXtables() { ip4tables "$@" && ip6tables "$@"; }
+
+        # XXX This fails with the original CAC CentOS 7 kernel.
+        if ipXtables -vL >/dev/null; then
+
+          #
+          # nat
+          #
+
+          # reset tables
+          ipXtables -t nat -F
+          ipXtables -t nat -X
+
+          #
+          ipXtables -t nat -A PREROUTING -j REDIRECT ! -i retiolum -p tcp --dport ssh --to-ports 0
+          ipXtables -t nat -A PREROUTING -j REDIRECT -p tcp --dport 11423 --to-ports ssh
+
+          #
+          # filter
+          #
+
+          # reset tables
+          ipXtables -P INPUT DROP
+          ipXtables -P FORWARD DROP
+          ipXtables -F
+          ipXtables -X
+
+          # create custom chains
+          ipXtables -N Retiolum
+
+          # INPUT
+          ipXtables -A INPUT -j ACCEPT -m conntrack --ctstate RELATED,ESTABLISHED
+          ipXtables -A INPUT -j ACCEPT -i lo
+          ipXtables -A INPUT -j ACCEPT -p tcp --dport ssh -m conntrack --ctstate NEW
+          #ipXtables -A INPUT -j ACCEPT -p tcp --dport http -m conntrack --ctstate NEW
+          ipXtables -A INPUT -j ACCEPT -p tcp --dport tinc -m conntrack --ctstate NEW
+          ipXtables -A INPUT -j ACCEPT -p tcp --dport smtp -m conntrack --ctstate NEW
+          ipXtables -A INPUT -j ACCEPT -p tcp --dport xmpp-client -m conntrack --ctstate NEW
+          ipXtables -A INPUT -j ACCEPT -p tcp --dport xmpp-server -m conntrack --ctstate NEW
+
+          ipXtables -A INPUT -j Retiolum -i retiolum
+          ${when log "ipXtables -A INPUT -j LOG --log-level info --log-prefix 'INPUT DROP '"}
+
+          # FORWARD
+          ${when log "ipXtables -A FORWARD -j LOG --log-level info --log-prefix 'FORWARD DROP '"}
+
+          # Retiolum
+          ip4tables -A Retiolum -j ACCEPT -p icmp --icmp-type echo-request
+          ip6tables -A Retiolum -j ACCEPT -p ipv6-icmp -m icmp6 --icmpv6-type echo-request
+
+          ipXtables -A Retiolum -j ACCEPT -p tcp --dport http -m conntrack --ctstate NEW
+
+          ${when log "ipXtables -A Retiolum -j LOG --log-level info --log-prefix 'REJECT '"}
+          ipXtables -A Retiolum -j REJECT -p tcp --reject-with tcp-reset
+          ip4tables -A Retiolum -j REJECT -p udp --reject-with icmp-port-unreachable
+          ip4tables -A Retiolum -j REJECT        --reject-with icmp-proto-unreachable
+          ip6tables -A Retiolum -j REJECT -p udp --reject-with icmp6-port-unreachable
+          ip6tables -A Retiolum -j REJECT
+        fi
+      '';
+}