package main

import (
	"fmt"
	"strings"
)

func renderRuleset(configuration config, publicInterface string) string {
	smtpObservationWindow := 600
	if configuration.SMTPDeny != nil {
		smtpObservationWindow = configuration.SMTPDeny.MaximumObservationWindow
	}
	httpQuarantine := ""
	if configuration.RelayHTTPQuarantineEnabled {
		httpQuarantine = fmt.Sprintf(`
        iifname %q tcp flags syn tcp dport 443 update @recent_https_v4 { ip saddr timeout %dm } delete @http_quarantine_v4 { ip saddr }
        iifname %q tcp flags syn tcp dport 80 ip saddr @http_quarantine_v4 counter drop
        iifname %q tcp flags syn tcp dport 80 ip saddr != @recent_https_v4 meter unmatched_http_by_source size %d { ip saddr timeout %dm limit rate over %d/hour burst %d packets } update @http_quarantine_v4 { ip saddr timeout %dm } counter drop`,
			publicInterface, configuration.RelayHTTPSRecentMinutes,
			publicInterface,
			publicInterface, configuration.RelayTrackerMaxSources, configuration.RelayHTTPSRecentMinutes, configuration.RelayUnmatchedHTTPRate, configuration.RelayUnmatchedHTTPBurst, configuration.RelayHTTPQuarantineMinutes)
	}
	mailForward := ""
	mailDNAT := ""
	mailGuard := ""
	if configuration.MailRelayAddress != "" {
		mailForward = fmt.Sprintf(`
    iifname %q oifname "wg-oci0" ip daddr %s tcp dport { 25, 465, 993 } accept`, publicInterface, configuration.MailRelayAddress)
		mailDNAT = fmt.Sprintf(`
    iifname %q tcp dport { 25, 465, 993 } dnat ip to %s`, publicInterface, configuration.MailRelayAddress)
		mailGuard = fmt.Sprintf(`
    iifname %q tcp flags syn tcp dport 25 ip saddr @smtp_syn_quarantine_v4 counter name smtp_syn_quarantine_dropped drop
    iifname %q tcp flags syn tcp dport 25 meter smtp_syn_by_source size %d { ip saddr timeout 1m limit rate over %d/minute burst %d packets } update @smtp_syn_quarantine_v4 { ip saddr timeout %ds } counter name smtp_syn_source_dropped drop
    iifname %q tcp flags syn tcp dport 25 limit rate over %d/second burst %d packets counter name smtp_syn_aggregate_dropped drop
    iifname %q tcp dport 25 limit rate over %d/second burst %d packets counter name smtp_packet_aggregate_dropped drop
    iifname %q tcp flags syn tcp dport { 465, 993 } ip saddr @auth_syn_quarantine_v4 counter name auth_syn_quarantine_dropped drop
    iifname %q tcp flags syn tcp dport { 465, 993 } meter auth_syn_by_source size %d { ip saddr timeout 1m limit rate over %d/minute burst %d packets } update @auth_syn_quarantine_v4 { ip saddr timeout 10m } counter name auth_syn_source_dropped drop
    iifname %q tcp flags syn tcp dport { 465, 993 } limit rate over %d/second burst %d packets counter name auth_syn_aggregate_dropped drop
    iifname %q tcp dport { 465, 993 } limit rate over %d/second burst %d packets counter name auth_packet_aggregate_dropped drop`,
			publicInterface,
			publicInterface, configuration.RelayTrackerMaxSources, configuration.RelaySMTPSYNRate, configuration.RelaySMTPSYNBurst, smtpObservationWindow,
			publicInterface, configuration.RelaySMTPSYNAggregateRate, configuration.RelaySMTPSYNAggregateBurst,
			publicInterface, configuration.RelaySMTPPacketAggregateRate, configuration.RelaySMTPPacketAggregateBurst,
			publicInterface,
			publicInterface, configuration.RelayTrackerMaxSources, configuration.RelayAuthSYNRate, configuration.RelayAuthSYNBurst,
			publicInterface, configuration.RelayAuthSYNAggregateRate, configuration.RelayAuthSYNAggregateBurst,
			publicInterface, configuration.RelayAuthPacketAggregateRate, configuration.RelayAuthPacketAggregateBurst)
	}
	return strings.TrimSpace(fmt.Sprintf(`
flush ruleset
table inet oci_l4_relay_web_allow {
  counter web_allow_denied {}
  chain ingress {
    type filter hook prerouting priority raw - 20; policy accept;
    iifname %q tcp dport { 80, 443, 465, 993 } counter name web_allow_denied drop
  }
}

table inet oci_l4_relay_smtp_deny {
  set denied_v4 {
    type ipv4_addr
    flags interval, timeout
  }
  counter smtp_denied {}
  chain ingress {
    type filter hook prerouting priority raw - 19; policy accept;
    iifname %q tcp dport 25 ip saddr @denied_v4 counter name smtp_denied drop
  }
}

table inet oci_l4_relay {
  counter web_packet_aggregate_dropped {}
  counter web_syn_quarantine_dropped {}
  counter web_syn_source_dropped {}
  counter web_syn_aggregate_dropped {}
  counter smtp_packet_aggregate_dropped {}
  counter smtp_syn_aggregate_dropped {}
  counter smtp_syn_quarantine_dropped {}
  counter smtp_syn_source_dropped {}
  counter auth_packet_aggregate_dropped {}
  counter auth_syn_aggregate_dropped {}
  counter auth_syn_quarantine_dropped {}
  counter auth_syn_source_dropped {}

  set recent_https_v4 {
    type ipv4_addr
    flags dynamic,timeout
    timeout %dm
    size %d
  }

  set http_quarantine_v4 {
    type ipv4_addr
    flags dynamic,timeout
    timeout %dm
    size %d
  }

  set syn_quarantine_v4 {
    type ipv4_addr
    flags dynamic,timeout
    counter
    timeout 1m
    size %d
  }

  set smtp_syn_quarantine_v4 {
    type ipv4_addr
    flags dynamic,timeout
    counter
    timeout %ds
    size %d
  }

  set auth_syn_quarantine_v4 {
    type ipv4_addr
    flags dynamic,timeout
    timeout 10m
    size %d
  }

  chain ingress_guard {
    type filter hook prerouting priority raw - 10; policy accept;%s
    iifname %q tcp flags syn tcp dport { 80, 443 } ip saddr @syn_quarantine_v4 counter name web_syn_quarantine_dropped drop
    iifname %q tcp flags syn tcp dport { 80, 443 } meter web_syn_by_source size %d { ip saddr timeout 1m limit rate over %d/minute burst %d packets } update @syn_quarantine_v4 { ip saddr timeout 1m } counter name web_syn_source_dropped drop
    iifname %q tcp flags syn tcp dport { 80, 443 } limit rate over %d/second burst %d packets counter name web_syn_aggregate_dropped drop
    iifname %q tcp dport { 80, 443 } limit rate over %d/second burst %d packets counter name web_packet_aggregate_dropped drop%s
  }

  chain input {
    type filter hook input priority filter; policy drop;
    iifname "lo" accept
    ct state established,related accept
    icmp type 3 icmp code 4 accept
    iifname %q udp dport %d accept
    iifname "wg-oci0" tcp dport %d accept
  }

  chain output {
    type filter hook output priority filter; policy drop;
    oifname "lo" accept
    ct state established,related accept
    ip daddr 169.254.169.254 tcp dport 80 accept
    ip daddr 169.254.169.254 udp dport { 53, 123 } accept
    ip daddr 169.254.169.254 tcp dport 53 accept
    udp sport 68 udp dport 67 accept
    udp sport %d accept
    tcp dport 443 accept
    icmp type { 3, 11, 12 } accept
  }

  chain forward {
    type filter hook forward priority filter; policy drop;
    ct state established,related accept
    iifname %q oifname "wg-oci0" ip daddr %s tcp dport { 80, 443 } accept%s
    iifname "wg-oci0" oifname %q ct state established,related accept
  }

  chain prerouting {
    type nat hook prerouting priority dstnat; policy accept;
    iifname %q tcp dport { 80, 443 } dnat ip to %s%s
  }
}
`, publicInterface, publicInterface,
		configuration.RelayHTTPSRecentMinutes, configuration.RelayTrackerMaxSources,
		configuration.RelayHTTPQuarantineMinutes, configuration.RelayTrackerMaxSources,
		configuration.RelayTrackerMaxSources,
		smtpObservationWindow,
		configuration.RelayTrackerMaxSources,
		configuration.RelayTrackerMaxSources,
		httpQuarantine,
		publicInterface,
		publicInterface, configuration.RelayTrackerMaxSources, configuration.RelayWebSYNRate, configuration.RelayWebSYNBurst,
		publicInterface, configuration.RelayWebSYNAggregateRate, configuration.RelayWebSYNAggregateBurst,
		publicInterface, configuration.RelayWebPacketAggregateRate, configuration.RelayWebPacketAggregateBurst,
		mailGuard,
		publicInterface, configuration.WireGuardListenPort, configuration.RelayMetricsPort,
		configuration.WireGuardListenPort,
		publicInterface, configuration.GatewayRelayAddress, mailForward, publicInterface,
		publicInterface, configuration.GatewayRelayAddress, mailDNAT)) + "\n"
}