Generating them unconditionally caused a problem with the init script:
the script required there to be a certificate for the private key if
the private key existed, but we do want to allow TCP-only configurations
and always having a private key prevented that.
Also, give the user advice on how to deal with this problem when it
arises in the init script.
We use SIGALRM to limit runtime of dpctl and ofp-discover. There is no
reason that we should not clean up after it in the same way as any other
catchable signal. In particular, ofp-discover wants to restore network
device flags on timeout.
The upcoming ofp-discover program wants to print out the binding
information, and dhcp_msg_to_string() is pretty close to what it
wants. But one-field-per-line is easier for other programs to parse.
This allows us to have DHCP clients that don't actually bind or unbind
a network device's IP address. This is useful for doing controller
discovery without actually reconfiguring a network device.
There's no need to set changed unconditionally in dhclient_init(), and
it can make extra work for the users of the dhclient, by causing them
to think that something changed when it didn't.
libtool was needed when NOX was directly linking against libopenflow.
Since it doesn't do that anymore, we can drop its use (and that makes
OpenFlow configure and build slightly faster).
This keeps vlogconf, in particular, from being linked against OpenSSL,
which in turn keeps the Debian package build tools from complaining that
the openflow-common package shouldn't need to depend on OpenSSL but does
because of the spurious library link.
We can't guarantee uniqueness of ip_id versus the host's, screwing up
fragment reassembly, so prevent fragmentation and use an all-zeros
ip_id. RFC 791 doesn't say we can do this, but Linux does the same
thing for DF packets, so it must not screw anything up.
The secure channel, in discovery mode, wants to enable TCP connections
by default only if SSL has not been configured. This function allows
it to do that.
One use case is when NOX is running on localhost, in which case waiting
for the full default backoff interval is unnecessary and undesirable.
Also changes default maximum backoff to 15 seconds (from 60).
Otherwise, the TCP/IP implementation is responsible for connection
attempt backoff, but we want to have some control over it ourselves.
In particular we want to initially back off faster and to log a
message upon connection attempt retransmission, to make it easier
to see what has happened from the log.
Ben Pfaff