hwsim tests: add a hwsim controller module

The controller module allows adding/destroying radios on the fly
with the recent hwsim changes.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

tests/hwsim/hwsim.py

@@ -0,0 +1,53 @@
+#
+# HWSIM generic netlink controller code
+# Copyright (c) 2014	Intel Corporation
+#
+# Author: Johannes Berg <johannes.berg@intel.com>
+#
+# This software may be distributed under the terms of the BSD license.
+# See README for more details.
+
+import netlink
+
+# constants
+HWSIM_CMD_CREATE_RADIO		= 4
+HWSIM_CMD_DESTROY_RADIO		= 5
+
+HWSIM_ATTR_CHANNELS		= 9
+HWSIM_ATTR_RADIO_ID		= 10
+
+# the controller class
+class HWSimController(object):
+    def __init__(self):
+        self._conn = netlink.Connection(netlink.NETLINK_GENERIC)
+        self._fid = netlink.genl_controller.get_family_id('MAC80211_HWSIM')
+
+    def create_radio(self, n_channels=None):
+        attrs = []
+        if n_channels:
+            attrs.append(netlink.U32Attr(HWSIM_ATTR_CHANNELS, n_channels))
+        msg = netlink.GenlMessage(self._fid, HWSIM_CMD_CREATE_RADIO,
+                                  flags = netlink.NLM_F_REQUEST |
+                                          netlink.NLM_F_ACK,
+                                  attrs = attrs)
+        return msg.send_and_recv(self._conn).ret
+
+    def destroy_radio(self, radio_id):
+        attrs = [netlink.U32Attr(HWSIM_ATTR_RADIO_ID, radio_id)]
+        msg = netlink.GenlMessage(self._fid, HWSIM_CMD_DESTROY_RADIO,
+                                  flags = netlink.NLM_F_REQUEST |
+                                          netlink.NLM_F_ACK,
+                                  attrs = attrs)
+        msg.send_and_recv(self._conn)
+
+if __name__ == '__main__':
+    import sys
+    c = HWSimController()
+    if sys.argv[1] == 'create':
+        if len(sys.argv) > 2:
+            n_channels = int(sys.argv[2])
+        else:
+            n_channels = 0
+        print 'Created radio %d' % c.create_radio(n_channels=n_channels)
+    elif sys.argv[1] == 'destroy':
+        print c.destroy_radio(int(sys.argv[2]))

tests/hwsim/netlink.py

@@ -0,0 +1,234 @@
+#
+# (Generic) Netlink message generation/parsing
+# Copyright (c) 2007	Johannes Berg <johannes@sipsolutions.net>
+# Copyright (c) 2014	Intel Corporation
+#
+# This software may be distributed under the terms of the BSD license.
+# See README for more details.
+
+import struct, socket
+
+# flags
+NLM_F_REQUEST = 1
+NLM_F_MULTI = 2
+NLM_F_ACK = 4
+NLM_F_ECHO = 8
+
+# types
+NLMSG_NOOP	= 1
+NLMSG_ERROR	= 2
+NLMSG_DONE	= 3
+NLMSG_OVERRUN	= 4
+NLMSG_MIN_TYPE	= 0x10
+
+class Attr(object):
+    def __init__(self, attr_type, data, *values):
+        self._type = attr_type
+        if len(values):
+            self._data = struct.pack(data, *values)
+        else:
+            self._data = data
+
+    def _dump(self):
+        hdr = struct.pack("HH", len(self._data) + 4, self._type)
+        length = len(self._data)
+        pad = ((length + 4 - 1) & ~3 ) - length
+        return hdr + self._data + '\0' * pad
+
+    def __repr__(self):
+        return '<Attr type %d, data "%s">' % (self._type, repr(self._data))
+
+    def u16(self):
+        return struct.unpack('H', self._data)[0]
+    def s16(self):
+        return struct.unpack('h', self._data)[0]
+    def u32(self):
+        return struct.unpack('I', self._data)[0]
+    def s32(self):
+        return struct.unpack('i', self._data)[0]
+    def str(self):
+        return self._data
+    def nulstr(self):
+        return self._data.split('\0')[0]
+    def nested(self):
+        return parse_attributes(self._data)
+
+class StrAttr(Attr):
+    def __init__(self, attr_type, data):
+        Attr.__init__(self, attr_type, "%ds" % len(data), data)
+
+class NulStrAttr(Attr):
+    def __init__(self, attr_type, data):
+        Attr.__init__(self, attr_type, "%dsB" % len(data), data, 0)
+
+class U32Attr(Attr):
+    def __init__(self, attr_type, val):
+        Attr.__init__(self, attr_type, "I", val)
+
+class U8Attr(Attr):
+    def __init__(self, attr_type, val):
+        Attr.__init__(self, attr_type, "B", val)
+
+class Nested(Attr):
+    def __init__(self, attr_type, attrs):
+        self.attrs = attrs
+        self.type = attr_type
+
+    def _dump(self):
+        contents = []
+        for attr in self.attrs:
+            contents.append(attr._dump())
+        contents = ''.join(contents)
+        length = len(contents)
+        hdr = struct.pack("HH", length+4, self.type)
+        return hdr + contents
+
+NETLINK_ROUTE		= 0
+NETLINK_UNUSED		= 1
+NETLINK_USERSOCK	= 2
+NETLINK_FIREWALL	= 3
+NETLINK_INET_DIAG	= 4
+NETLINK_NFLOG		= 5
+NETLINK_XFRM		= 6
+NETLINK_SELINUX		= 7
+NETLINK_ISCSI		= 8
+NETLINK_AUDIT		= 9
+NETLINK_FIB_LOOKUP	= 10
+NETLINK_CONNECTOR	= 11
+NETLINK_NETFILTER	= 12
+NETLINK_IP6_FW		= 13
+NETLINK_DNRTMSG		= 14
+NETLINK_KOBJECT_UEVENT	= 15
+NETLINK_GENERIC 	= 16
+
+class Message(object):
+    def __init__(self, msg_type, flags=0, seq=-1, payload=None):
+        self.type = msg_type
+        self.flags = flags
+        self.seq = seq
+        self.pid = -1
+        payload = payload or []
+        if isinstance(payload, list):
+            contents = []
+            for attr in payload:
+                contents.append(attr._dump())
+            self.payload = ''.join(contents)
+        else:
+            self.payload = payload
+
+    def send(self, conn):
+        if self.seq == -1:
+            self.seq = conn.seq()
+
+        self.pid = conn.pid
+        length = len(self.payload)
+
+        hdr = struct.pack("IHHII", length + 4*4, self.type,
+                          self.flags, self.seq, self.pid)
+        conn.send(hdr + self.payload)
+
+    def __repr__(self):
+        return '<netlink.Message type=%d, pid=%d, seq=%d, flags=0x%x "%s">' % (
+            self.type, self.pid, self.seq, self.flags, repr(self.payload))
+
+    @property
+    def ret(self):
+        assert self.type == NLMSG_ERROR
+        return struct.unpack("i", self.payload[:4])[0]
+
+    def send_and_recv(self, conn):
+        self.send(conn)
+        while True:
+            m = conn.recv()
+            if m.seq == self.seq:
+                return m
+
+class Connection(object):
+    def __init__(self, nltype, groups=0, unexpected_msg_handler=None):
+        self.descriptor = socket.socket(socket.AF_NETLINK,
+                                        socket.SOCK_RAW, nltype)
+        self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 65536)
+        self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 65536)
+        self.descriptor.bind((0, groups))
+        self.pid, self.groups = self.descriptor.getsockname()
+        self._seq = 0
+        self.unexpected = unexpected_msg_handler
+    def send(self, msg):
+        self.descriptor.send(msg)
+    def recv(self):
+        contents = self.descriptor.recv(16384)
+        # XXX: python doesn't give us message flags, check
+        #      len(contents) vs. msglen for TRUNC
+        msglen, msg_type, flags, seq, pid = struct.unpack("IHHII", 
+                                                          contents[:16])
+        msg = Message(msg_type, flags, seq, contents[16:])
+        msg.pid = pid
+        if msg.type == NLMSG_ERROR:
+            import os
+            errno = msg.ret
+            if errno < 0:
+                err = OSError("Netlink error: %s (%d)" % (
+                    os.strerror(-errno), -errno))
+                err.errno = -errno
+                raise err
+        return msg
+    def seq(self):
+        self._seq += 1
+        return self._seq
+
+def parse_attributes(data):
+    attrs = {}
+    while len(data):
+        attr_len, attr_type = struct.unpack("HH", data[:4])
+        attrs[attr_type] = Attr(attr_type, data[4:attr_len])
+        attr_len = ((attr_len + 4 - 1) & ~3 )
+        data = data[attr_len:]
+    return attrs
+
+
+
+CTRL_CMD_UNSPEC		= 0
+CTRL_CMD_NEWFAMILY	= 1
+CTRL_CMD_DELFAMILY	= 2
+CTRL_CMD_GETFAMILY	= 3
+CTRL_CMD_NEWOPS		= 4
+CTRL_CMD_DELOPS		= 5
+CTRL_CMD_GETOPS		= 6
+
+CTRL_ATTR_UNSPEC	= 0
+CTRL_ATTR_FAMILY_ID	= 1
+CTRL_ATTR_FAMILY_NAME	= 2
+CTRL_ATTR_VERSION	= 3
+CTRL_ATTR_HDRSIZE	= 4
+CTRL_ATTR_MAXATTR	= 5
+CTRL_ATTR_OPS		= 6
+
+class GenlHdr(object):
+    def __init__(self, cmd, version = 0):
+        self.cmd = cmd
+        self.version = version
+    def _dump(self):
+        return struct.pack("BBxx", self.cmd, self.version)
+
+def _genl_hdr_parse(data):
+    return GenlHdr(*struct.unpack("BBxx", data))
+
+GENL_ID_CTRL		= NLMSG_MIN_TYPE
+
+class GenlMessage(Message):
+    def __init__(self, family, cmd, attrs=[], flags=0):
+        Message.__init__(self, family, flags=flags, payload=[GenlHdr(cmd)] + attrs)
+
+class GenlController(object):
+    def __init__(self, conn):
+        self.conn = conn
+    def get_family_id(self, family):
+        a = NulStrAttr(CTRL_ATTR_FAMILY_NAME, family)
+        m = GenlMessage(GENL_ID_CTRL, CTRL_CMD_GETFAMILY, flags=NLM_F_REQUEST, attrs=[a])
+        m.send(self.conn)
+        m = self.conn.recv()
+        gh = _genl_hdr_parse(m.payload[:4])
+        attrs = parse_attributes(m.payload[4:])
+        return attrs[CTRL_ATTR_FAMILY_ID].u16()
+
+genl_controller = GenlController(Connection(NETLINK_GENERIC))