1 files changed, 189 insertions, 0 deletions

diff --git a/hosts/surtr/vpn/ruleset.nft b/hosts/surtr/vpn/ruleset.nft
new file mode 100644
index 00000000..3cdb7a8a
--- /dev/null
+++ b/hosts/surtr/vpn/ruleset.nft
@@ -0,0 +1,189 @@
+define icmp_protos = {ipv6-icmp, icmp, igmp}
+
+table arp filter {
+  limit lim_arp {
+    rate over 50 mbytes/second burst 50 mbytes
+  }
+
+  counter arp-rx {}
+  counter arp-tx {}
+
+  counter arp-ratelimit-rx {}
+  counter arp-ratelimit-tx {}
+
+  chain input {
+    type filter hook input priority filter
+    policy accept
+
+    limit name lim_arp counter name arp-ratelimit-rx drop
+
+    counter name arp-rx
+  }
+
+  chain output {
+    type filter hook output priority filter
+    policy accept
+
+    limit name lim_arp counter name arp-ratelimit-tx drop
+
+    counter name arp-tx
+  }
+}
+
+table inet filter {
+  limit lim_reject {
+    rate over 1000/second burst 1000 packets
+  }
+
+  limit lim_icmp {
+    rate over 50 mbytes/second burst 50 mbytes
+  }
+
+  counter invalid-fw {}
+  counter fw-lo {}
+  counter fw-vpn {}
+  counter fw-upstream {}
+
+  counter icmp-ratelimit-upstream-fw {}
+  counter icmp-ratelimit-vpn-fw {}
+  counter icmp-ratelimit-established-fw {}
+
+  counter icmp-upstream-fw {}
+  counter icmp-vpn-fw {}
+  counter icmp-established-fw {}
+
+  counter reject-ratelimit-fw {}
+  counter reject-fw {}
+  counter reject-tcp-fw {}
+  counter reject-icmp-fw {}
+
+  counter drop-fw {}
+
+  counter invalid-rx {}
+
+  counter rx-lo {}
+  counter invalid-local4-rx {}
+  counter invalid-local6-rx {}
+
+  counter icmp-ratelimit-rx {}
+  counter icmp-rx {}
+
+  counter wg-rx {}
+
+  counter established-rx {}
+
+  counter reject-ratelimit-rx {}
+  counter reject-rx {}
+  counter reject-tcp-rx {}
+  counter reject-icmp-rx {}
+
+  counter drop-rx {}
+
+  counter tx-lo {}
+
+  counter icmp-ratelimit-tx {}
+  counter icmp-tx {}
+
+  counter wg-tx {}
+
+  counter tx {}
+
+  chain forward {
+    type filter hook forward priority filter
+    policy drop
+
+
+    ct state invalid log level debug prefix "vpn: drop invalid forward: " counter name invalid-fw drop
+
+
+    iifname lo counter name fw-lo accept
+
+    meta l4proto $icmp_protos iifname upstream limit name lim_icmp counter name icmp-ratelimit-upstream-fw drop
+    meta l4proto $icmp_protos iifname upstream counter name icmp-upstream-fw accept
+    meta l4proto $icmp_protos iifname vpn limit name lim_icmp counter name icmp-ratelimit-vpn-fw drop
+    meta l4proto $icmp_protos iifname vpn counter name icmp-vpn-fw accept
+    meta l4proto $icmp_protos ct state {established, related} limit name lim_icmp counter name icmp-ratelimit-established-fw drop
+    meta l4proto $icmp_protos ct state {established, related} counter name icmp-established-fw accept
+
+
+    iifname upstream oifname vpn ct state {established, related} counter name fw-vpn accept
+    iifname vpn oifname upstream counter name fw-upstream accept
+
+
+    limit name lim_reject log level debug prefix "vpn: drop forward: " counter name reject-ratelimit-fw drop
+    log level debug prefix "vpn: reject forward: " counter name reject-fw
+    meta l4proto tcp ct state new counter name reject-tcp-fw reject with tcp reset
+    ct state new counter name reject-icmp-fw reject
+
+
+    counter name drop-fw
+  }
+
+  chain input {
+    type filter hook input priority filter
+    policy drop
+
+
+    ct state invalid log level debug prefix "vpn: drop invalid input: " counter name invalid-rx drop
+    
+
+    iifname lo counter name rx-lo accept
+    iif != lo ip daddr 127.0.0.1/8 counter name invalid-local4-rx reject
+    iif != lo ip6 daddr ::1/128 counter name invalid-local6-rx reject
+
+    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-rx drop
+    meta l4proto $icmp_protos counter name icmp-rx accept
+
+    udp dport 51820 counter name wg-rx accept
+
+    ct state {established, related} counter name established-rx accept
+
+
+    limit name lim_reject log level debug prefix "vpn: drop input: " counter name reject-ratelimit-rx drop
+    log level debug prefix "vpn: reject input: " counter name reject-rx
+    meta l4proto tcp ct state new counter name reject-tcp-rx reject with tcp reset
+    ct state new counter name reject-icmp-rx reject
+
+
+    counter name drop-rx
+  }
+
+  chain output {
+    type filter hook output priority filter
+    policy accept
+
+
+    oifname lo counter name tx-lo accept
+
+    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-tx drop
+    meta l4proto $icmp_protos counter name icmp-tx accept
+
+
+    udp sport 51820 counter name wg-tx
+    
+
+    counter name tx
+  }
+}
+
+table inet nat {
+  counter nat {}
+  
+  chain postrouting {
+    type nat hook postrouting priority srcnat
+    policy accept
+
+    iifname vpn counter name nat masquerade
+  }
+}
+
+table ip mss_clamp {
+  counter mss-clamp {}
+
+  chain postrouting {
+    type filter hook postrouting priority mangle
+    policy accept
+
+    iifname vpn oifname upstream tcp flags & (syn|rst) == syn counter name mss-clamp tcp option maxseg size set rt mtu
+  }
+}
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