Initial import

[ldd.git] / ldd / filters.py

diff --git a/ldd/filters.py b/ldd/filters.py
new file mode 100644 (file)
index 0000000..a1798c8
--- /dev/null
+++ b/ldd/filters.py
@@ -0,0 +1,98 @@
+#    ldd - DNS implementation in Python
+#    Copyright (C) 2006 Fredrik Tolf <fredrik@dolda2000.com>
+#
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+import socket
+import time
+import fcntl
+import struct
+
+import server
+
+def linuxifip4hack(ifname):
+    req = ifname + ("\0" * (32 - len(ifname)))
+    sk = socket.socket()
+    res = fcntl.ioctl(sk.fileno(), 0x8915, req)
+    sk.close()
+    sockaddr = res[16:]
+    return sockaddr[4:8]
+
+class valuecache:
+    def __init__(self, func, expire):
+        self.func = func
+        self.expire = expire
+        self.last = 0
+
+    def __call__(self, *args):
+        now = int(time.time())
+        if self.last == 0 or now - self.last > self.expire:
+            self.val = self.func(*(args))
+            self.last = now
+        return self.val
+
+class prefix6to4(server.handler):
+    def __init__(self, next, v4addr):
+        self.next = next
+        if callable(v4addr):
+            self.packed = v4addr
+        elif len(v4addr) == 4:
+            self.packed = v4addr
+        else:
+            self.packed = socket.inet_pton(socket.AF_INET, v4addr)
+
+    def handle(self, *args):
+        resp = self.next.handle(*args)
+        if resp is None:
+            return None
+        for rr in resp.allrrs():
+            if rr.head.istype("AAAA"):
+                addr = rr.data["address"]
+                if addr[0:6] == "\x20\x02\x00\x00\x00\x00":
+                    packed = self.packed
+                    if callable(packed):
+                        packed = packed()
+                    addr = addr[0:2] + packed + addr[6:]
+                    rr.data["address"] = addr
+        return resp
+
+class addrfilter(server.handler):
+    def __init__(self, default = None, matchers = []):
+        self.matchers = matchers
+        self.default = default
+
+    def setdefault(self, handler):
+        self.default = handler
+
+    def addmatcher(self, af, prefix, preflen, handler):
+        self.matchers += [(af, socket.inet_pton(af, prefix), preflen, handler)]
+    
+    def handle(self, query, pkt, origin):
+        matchlen = -1
+        match = self.default
+        if pkt.addr is not None:
+            for af, prefix, preflen, handler in self.matchers:
+                if pkt.addr[0] == af:
+                    addr = socket.inet_pton(af, pkt.addr[1])
+                    bytes = preflen >> 3
+                    restmask = 255 ^ ((1 << (8 - (preflen & 7))) - 1)
+                    if prefix[0:bytes] == addr[0:bytes] and \
+                           (ord(prefix[bytes]) & restmask) == (ord(addr[bytes]) & restmask):
+                        if preflen > matchlen:
+                            matchlen = preflen
+                            match = handler
+        if match is not None:
+            return match.handle(query, pkt, origin)
+        return None