From 8863eed9249204f3c2159f42d33a30491fade804 Mon Sep 17 00:00:00 2001
From: Jeltz <jeltz@auro.re>
Date: Wed, 21 Dec 2022 16:39:28 +0100
Subject: [PATCH] bird: add minimal BGP support

---
 roles/bird/defaults/main.yml      |   2 +
 roles/bird/templates/bird.conf.j2 | 101 ++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)

diff --git a/roles/bird/defaults/main.yml b/roles/bird/defaults/main.yml
index e053da4..2fa912c 100644
--- a/roles/bird/defaults/main.yml
+++ b/roles/bird/defaults/main.yml
@@ -8,4 +8,6 @@ bird__ospf_dead: 20
 bird__radv_interfaces: {}
 bird__radv_dns_servers: []
 bird__radv_max_interval: 5
+bird__static_unreachable: []
+bird__bgp_sessions: []
 ...
diff --git a/roles/bird/templates/bird.conf.j2 b/roles/bird/templates/bird.conf.j2
index a369d93..bcb13c6 100644
--- a/roles/bird/templates/bird.conf.j2
+++ b/roles/bird/templates/bird.conf.j2
@@ -27,6 +27,29 @@ protocol kernel kernel6 {
     };
 }
 
+
+{% if bird__static_unreachable | ansible.utils.ipv4 %}
+protocol static unreachable4 {
+	ipv4 {
+		export all;
+	};
+{% for route in bird__static_unreachable | ansible.utils.ipv4 %}
+	route {{ route }} unreachable;
+{% endfor %}
+}
+{% endif %}
+
+{% if bird__static_unreachable | ansible.utils.ipv6 %}
+protocol static unreachable6 {
+	ipv6 {
+		export all;
+	};
+{% for route in bird__static_unreachable | ansible.utils.ipv6 %}
+	route {{ route }} unreachable;
+{% endfor %}
+}
+{% endif %}
+
 protocol ospf v2 ospf4 {
 
     ipv4 {
@@ -83,6 +106,84 @@ protocol ospf v3 ospf6 {
 
 }
 
+{% for session in bird__bgp_sessions %}
+protocol bgp {{ session.name }} {
+
+    local as {{ session.local.as }};
+    source address {{ session.local.address }};
+    neighbor {{ session.remote.address }} as {{ session.remote.as }};
+
+    ipv4 {
+        import filter {
+{%  for pref in session.import.local_pref | default([]) %}
+{%
+     set networks =
+         pref.prefix
+         | product("+" if pref.sub else "")
+         | map("join")
+         | join(", ")
+%}
+{%   set operator = '!~' if pref.negate | default(False) else '~' %}
+            if (net {{ operator }} [ {{ networks }} ]) then {
+                bgp_local_pref = {{ pref.pref | int }};
+            }
+{%  endfor %}
+{%  if session.import.accept == "all" %}
+            accept;
+{%  else %}
+{%   for accept in session.import.accept | default([]) %}
+{%
+      set networks =
+          accept.prefix
+          | product("+" if accept.sub else "")
+          | map("join")
+          | join(", ")
+%}
+{%    set operator = '!~' if accept.negate | default(False) else '~' %}
+            if (net {{ operator }} [ {{ networks }} ]) then accept;
+{%   endfor %}
+            reject;
+{%  endif %}
+        };
+        export filter {
+{%  for prepend in session.export.as_prepend | default([]) %}
+{%
+     set networks =
+         prepend.prefix
+         | product("+" if prepend.sub else "")
+         | map("join")
+         | join(", ")
+%}
+{%   set operator = '!~' if prepend.negate | default(False) else '~' %}
+            if (net {{ operator }} [ {{ networks }} ]) then {
+{%   for _ in range(prepend.size) %}
+                bgp_path.prepend({{ session.local.as }});
+{%   endfor %}
+            }
+{%  endfor %}
+{%  if session.export.accept == "all" %}
+            accept;
+{%  else %}
+{%   for accept in session.export.accept | default([]) %}
+{%
+      set networks =
+          accept.prefix
+          | product("+" if accept.sub else "")
+          | map("join")
+          | join(", ")
+%}
+{%    set operator = '!~' if accept.negate | default(False) else '~' %}
+            if (net {{ operator }} [ {{ networks }} ]) then accept;
+{%   endfor %}
+            reject;
+{%  endif %}
+        };
+    };
+
+}
+
+{% endfor %}
+
 {% if bird__radv_interfaces %}
 protocol radv {