commit 1869936ca45ddd1c00089f7c2a678f2e0579f503
Author: Nick Bouwhuis <nick@bouwhuis.net>
Date:   Sat Mar 4 22:02:15 2023 +0100

    first commit

diff --git a/check_as_path.py b/check_as_path.py
new file mode 100644
index 0000000..f20eb23
--- /dev/null
+++ b/check_as_path.py
@@ -0,0 +1,29 @@
+import requests
+import argparse
+import sys
+
+def check_as_path(prefix, as_to_check):
+    url = f'https://stat.ripe.net/data/looking-glass/data.json?resource={prefix}'
+    response = requests.get(url)
+    if response.ok:
+        data = response.json()
+        for rrc in data['data']['rrcs']:
+            for peer in rrc['peers']:
+                as_path = peer['as_path']
+                if as_to_check in as_path:
+                    print(f"CRITICAL: AS {as_to_check} found in AS path for prefix {prefix} at RRC {rrc['rrc']}")
+                    return 2  # return critical
+        print(f"OK: AS {as_to_check} not found in AS path for prefix {prefix}")
+        return 0  # return OK
+    else:
+        print(f"UNKNOWN: Error fetching data from {url}")
+        return 3  # return unknown
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Check if a certain AS is in the AS path for any peers for a given prefix')
+    parser.add_argument('--prefix', required=True, help='IPv4 prefix to check')
+    parser.add_argument('--asn', required=True, help='AS number to check for')
+    args = parser.parse_args()
+    exit_code = check_as_path(args.prefix, args.asn)
+    sys.exit(exit_code)
+