minor improvements, add tests for ipv4-mapped addresses

mitmproxy/platform/osx.py

@@ -1,7 +1,6 @@
 import subprocess
 
 from . import pf
-import re
 
 """
     Doing this the "right" way by using DIOCNATLOOK on the pf device turns out
@@ -16,7 +15,6 @@ import re
 """
 
 STATECMD = ("sudo", "-n", "/sbin/pfctl", "-s", "state")
-ipv4_mapped = re.compile("^::ffff:\d+.\d+.\d+.\d+$")
 
 
 def original_addr(csock):
@@ -35,6 +33,4 @@ def original_addr(csock):
         raise RuntimeError(
             "Insufficient privileges to access pfctl. "
             "See http://docs.mitmproxy.org/en/latest/transparent/osx.html for details.")
-    if ipv4_mapped.match(peer[0]):
-        return pf.lookup(peer[0].replace("::ffff:", ""), peer[1], stxt)
     return pf.lookup(peer[0], peer[1], stxt)

mitmproxy/platform/pf.py

@@ -1,3 +1,4 @@
+import re
 import sys
 
 
@@ -8,6 +9,9 @@ def lookup(address, port, s):
 
         Returns an (address, port) tuple, or None.
     """
+    # We may get an ipv4-mapped ipv6 address here, e.g. ::ffff:127.0.0.1.
+    # Those still appear as "127.0.0.1" in the table, so we need to strip the prefix.
+    address = re.sub("^::ffff:(?=\d+.\d+.\d+.\d+$)", "", address)
     s = s.decode()
     spec = "%s:%s" % (address, port)
     for i in s.split("\n"):

test/mitmproxy/platform/test_pf.py

@@ -15,6 +15,7 @@ class TestLookup:
             d = f.read()
 
         assert pf.lookup("192.168.1.111", 40000, d) == ("5.5.5.5", 80)
+        assert pf.lookup("::ffff:192.168.1.111", 40000, d) == ("5.5.5.5", 80)
         with pytest.raises(Exception, match="Could not resolve original destination"):
             pf.lookup("192.168.1.112", 40000, d)
         with pytest.raises(Exception, match="Could not resolve original destination"):