match IPs more robustly and multiple per line

respodns/ip_util.py

@@ -1,17 +1,24 @@
 import re
 
 ipv4_pattern = re.compile(r"(\d+)\.(\d+)\.(\d+)\.(\d+)", re.ASCII)
+ipv4_pattern_strict = re.compile(r"""
+(?:^|(?<=[^\d.]))
+(0|1\d\d|2[0-4]\d|25[0-5]|[1-9]\d?)
+\.
+(0|1\d\d|2[0-4]\d|25[0-5]|[1-9]\d?)
+\.
+(0|1\d\d|2[0-4]\d|25[0-5]|[1-9]\d?)
+\.
+(0|1\d\d|2[0-4]\d|25[0-5]|[1-9]\d?)
+(?:$|(?=[^\d.]))
+""", re.ASCII | re.VERBOSE)
 
 
 def read_ips(f):
-    # TODO: make more robust. (regex pls)
-    for ip in f.readlines():
-        if "#" in ip:
-            ip, _, _ = ip.partition("#")
-        ip = ip.strip()
-        if ip.count(".") != 3:
-            continue
-        yield ip
+    for line in f.readlines():
+        line, _, _ = line.partition("#")  # ignore comments
+        for match in ipv4_pattern_strict.finditer(line):
+            yield match.group()  # yield the entire string
 
 
 def addr_to_int(ip):