Call netdevice's poll() and transmit() methods only when device is open.

net_device is unregistered.

out-of-range ACK.

Simplify checksum generation on the TX datapath.

Move routing into a separate function

Truncate TX length to TCP window at time of transmission rather than at
time of adding to TX packet; this is conceptually cleaner and also allows
the application to call tcp_send() multiple times to build up a single
packet.

"flags that are currently being sent".  This allows at least one special
case (checking that we haven't already sent a FIN in tcp_rx_fin()) to be
collapsed.

reopen connection.  (The TCP API will soon change to render this step
unnecessary.)

TargetAddress from the login response, because we still need the old
address while we close the connection!

phase.  In iscsi_issue(), detect this state and immediately refuse the
operation.  This avoids trying multiple logins when scsi.c tries
several times to read the drive capacity.

reconnection mechanism.  This avoids the problems of trying to reuse
the TCP connection structure before the old connection has cleanly exited.

TCP_CLOSED state (i.e. after the final FIN/ACK exchange), and has been
removed from the list of TCP connections.

Remove the now-totally-obsolete sockaddr_in field from tcp.h.

Added CHAP authentication

negotiation phases, to allow inclusion of CHAP authentication.

defined in vsprintf.h.  (This may change, since vsprintf.h is a
non-standard name, but for now it's the one to use.)

There should be no need to include vsprintf.h just for DBG() statements,
since include/compiler.h forces it in for a debug build anyway.

list.