Replace most uses of and references to "ifconfig" by "ip".

It's becoming more common that OSes include "ip" but not "ifconfig", so
it's best to avoid using the latter.  This commit removes most references
to "ifconfig" and replaces them by "ip".  It also adds a build-time check
to make it harder to introduce new uses of "ifconfig".

There are important differences between "ifconfig" and "ip":

- An "ifconfig" command that sets an IP address also brings the interface
  up, but a similar "ip addr add" command does not, so it is often necessary
  (or at least precautionary) to add an "ip link set <dev> up" command.

- "ifconfig" can infer a netmask from an IP adddress, but "ip" always
  assumes /32 if none is given.

- "ifconfig" with address 0.0.0.0 removes any configured IP address, but
  "ip addr add" does not, so "ifconfig <dev> 0.0.0.0" must be replaced by
  "ip addr del" or "ip addr flush".

Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 5 insertions, 6 deletions

diff --git a/Documentation/tutorials/ovs-advanced.rst b/Documentation/tutorials/ovs-advanced.rst
index 15785cf5b..676137f3c 100644
--- a/Documentation/tutorials/ovs-advanced.rst
+++ b/Documentation/tutorials/ovs-advanced.rst
@@ -103,10 +103,9 @@ From Open vSwitch's perspective, the bridge that you create this way is as real
 as any other.  You can, for example, connect it to an OpenFlow controller or
 use ``ovs-ofctl`` to examine and modify it and its OpenFlow flow table.  On the
 other hand, the bridge is not visible to the operating system's network stack,
-so ``ifconfig`` or ``ip`` cannot see it or affect it, which means that
-utilities like ``ping`` and ``tcpdump`` will not work either.  (That has its
-good side, too: you can't screw up your computer's network stack by
-manipulating a sandboxed OVS.)
+so ``ip`` cannot see it or affect it, which means that utilities like ``ping``
+and ``tcpdump`` will not work either.  (That has its good side, too: you can't
+screw up your computer's network stack by manipulating a sandboxed OVS.)
 
 When you're done using OVS from the sandbox, exit the nested shell (by entering
 the "exit" shell command or pressing Control+D).  This will kill the daemons
@@ -267,9 +266,9 @@ In addition to adding a port, the ``ovs-vsctl`` command above sets its
   we can talk about OpenFlow port 1 and know that it corresponds to ``p1``.
 
 The ``ovs-ofctl`` command above brings up the simulated interfaces, which are
-down initially, using an OpenFlow request.  The effect is similar to ``ifconfig
+down initially, using an OpenFlow request.  The effect is similar to ``ip link
 up``, but the sandbox's interfaces are not visible to the operating system and
-therefore ``ifconfig`` would not affect them.
+therefore ``ip`` would not affect them.
 
 We have not configured anything related to VLANs or MAC learning.  That's
 because we're going to implement those features in the flow table.