[trivial] Add missing helper from resync

.coverage

@@ -0,0 +1 @@
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charm-helpers-hooks.yaml

@@ -9,3 +9,4 @@ include:
         - apache
         - cluster
     - payload.execd
+    - contrib.network.ip

hooks/charmhelpers/contrib/network/ip.py

@@ -0,0 +1,156 @@
+import sys
+
+from functools import partial
+
+from charmhelpers.fetch import apt_install
+from charmhelpers.core.hookenv import (
+    ERROR, log,
+)
+
+try:
+    import netifaces
+except ImportError:
+    apt_install('python-netifaces')
+    import netifaces
+
+try:
+    import netaddr
+except ImportError:
+    apt_install('python-netaddr')
+    import netaddr
+
+
+def _validate_cidr(network):
+    try:
+        netaddr.IPNetwork(network)
+    except (netaddr.core.AddrFormatError, ValueError):
+        raise ValueError("Network (%s) is not in CIDR presentation format" %
+                         network)
+
+
+def get_address_in_network(network, fallback=None, fatal=False):
+    """
+    Get an IPv4 or IPv6 address within the network from the host.
+
+    :param network (str): CIDR presentation format. For example,
+        '192.168.1.0/24'.
+    :param fallback (str): If no address is found, return fallback.
+    :param fatal (boolean): If no address is found, fallback is not
+        set and fatal is True then exit(1).
+
+    """
+
+    def not_found_error_out():
+        log("No IP address found in network: %s" % network,
+            level=ERROR)
+        sys.exit(1)
+
+    if network is None:
+        if fallback is not None:
+            return fallback
+        else:
+            if fatal:
+                not_found_error_out()
+
+    _validate_cidr(network)
+    network = netaddr.IPNetwork(network)
+    for iface in netifaces.interfaces():
+        addresses = netifaces.ifaddresses(iface)
+        if network.version == 4 and netifaces.AF_INET in addresses:
+            addr = addresses[netifaces.AF_INET][0]['addr']
+            netmask = addresses[netifaces.AF_INET][0]['netmask']
+            cidr = netaddr.IPNetwork("%s/%s" % (addr, netmask))
+            if cidr in network:
+                return str(cidr.ip)
+        if network.version == 6 and netifaces.AF_INET6 in addresses:
+            for addr in addresses[netifaces.AF_INET6]:
+                if not addr['addr'].startswith('fe80'):
+                    cidr = netaddr.IPNetwork("%s/%s" % (addr['addr'],
+                                                        addr['netmask']))
+                    if cidr in network:
+                        return str(cidr.ip)
+
+    if fallback is not None:
+        return fallback
+
+    if fatal:
+        not_found_error_out()
+
+    return None
+
+
+def is_ipv6(address):
+    '''Determine whether provided address is IPv6 or not'''
+    try:
+        address = netaddr.IPAddress(address)
+    except netaddr.AddrFormatError:
+        # probably a hostname - so not an address at all!
+        return False
+    else:
+        return address.version == 6
+
+
+def is_address_in_network(network, address):
+    """
+    Determine whether the provided address is within a network range.
+
+    :param network (str): CIDR presentation format. For example,
+        '192.168.1.0/24'.
+    :param address: An individual IPv4 or IPv6 address without a net
+        mask or subnet prefix. For example, '192.168.1.1'.
+    :returns boolean: Flag indicating whether address is in network.
+    """
+    try:
+        network = netaddr.IPNetwork(network)
+    except (netaddr.core.AddrFormatError, ValueError):
+        raise ValueError("Network (%s) is not in CIDR presentation format" %
+                         network)
+    try:
+        address = netaddr.IPAddress(address)
+    except (netaddr.core.AddrFormatError, ValueError):
+        raise ValueError("Address (%s) is not in correct presentation format" %
+                         address)
+    if address in network:
+        return True
+    else:
+        return False
+
+
+def _get_for_address(address, key):
+    """Retrieve an attribute of or the physical interface that
+    the IP address provided could be bound to.
+
+    :param address (str): An individual IPv4 or IPv6 address without a net
+        mask or subnet prefix. For example, '192.168.1.1'.
+    :param key: 'iface' for the physical interface name or an attribute
+        of the configured interface, for example 'netmask'.
+    :returns str: Requested attribute or None if address is not bindable.
+    """
+    address = netaddr.IPAddress(address)
+    for iface in netifaces.interfaces():
+        addresses = netifaces.ifaddresses(iface)
+        if address.version == 4 and netifaces.AF_INET in addresses:
+            addr = addresses[netifaces.AF_INET][0]['addr']
+            netmask = addresses[netifaces.AF_INET][0]['netmask']
+            cidr = netaddr.IPNetwork("%s/%s" % (addr, netmask))
+            if address in cidr:
+                if key == 'iface':
+                    return iface
+                else:
+                    return addresses[netifaces.AF_INET][0][key]
+        if address.version == 6 and netifaces.AF_INET6 in addresses:
+            for addr in addresses[netifaces.AF_INET6]:
+                if not addr['addr'].startswith('fe80'):
+                    cidr = netaddr.IPNetwork("%s/%s" % (addr['addr'],
+                                                        addr['netmask']))
+                    if address in cidr:
+                        if key == 'iface':
+                            return iface
+                        else:
+                            return addr[key]
+    return None
+
+
+get_iface_for_address = partial(_get_for_address, key='iface')
+
+get_netmask_for_address = partial(_get_for_address, key='netmask')