1 files changed, 113 insertions, 0 deletions
diff --git a/tools/python/xen/util/ip.py b/tools/python/xen/util/ip.py
new file mode 100644
index 0000000000..8396e0d014
--- /dev/null
+++ b/tools/python/xen/util/ip.py
@@ -0,0 +1,113 @@
+import os
+import re
+import socket
+import struct
+
+def readlines(fd):
+    """Version of readlines safe against EINTR.
+    """
+    import errno
+    
+    lines = []
+    while 1:
+        try:
+            line = fd.readline()
+        except IOError, ex:
+            if ex.errno == errno.EINTR:
+                continue
+            else:
+                raise
+        if line == '': break
+        lines.append(line)
+    return lines
+
+def readline(fd):
+    """Version of readline safe against EINTR.
+    """
+    while 1:
+        try:
+            return fd.readline()
+        except IOError, ex:
+            if ex.errno == errno.EINTR:
+                continue
+            else:
+                raise
+
+##### Networking-related functions
+
+"""Bridge for network backend.
+When bridging is used, eth0 may not have an IP address,
+as it may have been moved onto the bridge.
+"""
+NBE_BRIDGE = 'nbe-br'
+
+def get_current_ipaddr(dev='eth0'):
+    """Return a string containing the primary IP address for the given
+    network interface (default 'eth0').
+    """
+    fd = os.popen( '/sbin/ifconfig ' + dev + ' 2>/dev/null' )
+    lines = readlines(fd)
+    for line in lines:
+        m = re.search( '^\s+inet addr:([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+).*',
+                       line )
+        if m:
+            return m.group(1)
+    if dev == 'eth0':
+        return get_current_ipaddr(NBE_BRIDGE)
+    return None
+
+def get_current_ipmask(dev='eth0'):
+    """Return a string containing the primary IP netmask for the given
+    network interface (default 'eth0').
+    """
+    fd = os.popen( '/sbin/ifconfig ' + dev + ' 2>/dev/null' )
+    lines = readlines(fd)
+    for line in lines:
+        m = re.search( '^.+Mask:([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+).*',
+                       line )
+        if m:
+            return m.group(1)
+    if dev == 'eth0':
+        return get_current_ipmask(NBE_BRIDGE)
+    return None
+
+def get_current_ipgw(dev='eth0'):
+    """Return a string containing the IP gateway for the given
+    network interface (default 'eth0').
+    """
+    fd = os.popen( '/sbin/route -n' )
+    lines = readlines(fd)
+    for line in lines:
+        m = re.search( '^\S+\s+([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)' +
+                       '\s+\S+\s+\S*G.*' + dev + '.*', line )
+        if m:
+            return m.group(1)
+    if dev == 'eth0':
+        return get_current_ipgw(NBE_BRIDGE)
+    return None
+
+def inet_aton(addr):
+    """Convert an IP addr in IPv4 dot notation into an int.
+    """
+    b = socket.inet_aton(addr)
+    return struct.unpack('!I', b)[0]
+
+def inet_ntoa(n):
+    """Convert an int into an IP addr in IPv4 dot notation.
+    """
+    b = struct.pack('!I', n)
+    return socket.inet_ntoa(b)
+
+def add_offset_to_ip(addr, offset):
+    """Add a numerical offset to an IP addr in IPv4 dot notation.
+    """
+    n = inet_aton(addr)
+    n += offset
+    return inet_ntoa(n)
+
+def check_subnet( ip, network, netmask ):
+    n_ip = inet_aton(ip)
+    n_net = inet_aton(network)
+    n_mask = inet_aton(netmask)
+    return (n_ip & n_mask) == (n_net & n_mask)
+