Added a large number of missing calls to free_pkb().  In the case of UDP,
no received packets were ever freed, which lead to memory exhaustion
remarkably quickly once pxelinux started up.

In general, any function with _rx() in its name which accepts a pk_buff
*must* either call free_pkb() or pass the pkb to another _rx() function
(e.g. the next layer up the stack).  Since the UDP (and TCP) layers don't
pass packet buffers up to the higher-layer protocols (the
"applications"), they must free the packet buffer after calling the
application's newdata() method.

a separate function.

static since otherwise gcc4 optimises them away completely.  Also, it
really *is* an error if the table start and end are unused, so they
certainly shouldn't be marked with attribute unused.

Start updating iscsi.c to use Nikhil's TCP API.

udp_connect() now follows the standard BSD sockets semantics and simply
sets the default address for outgoing packets; it doesn't filter incoming
packets.

Updated PXE API dispatcher to use copy_{to,from}_user, and moved to
arch/i386 since the implementation is quite architecture-dependent.
(The individual PXE API calls can be largely
architecture-independent.)

Introduced struct sockaddr_tcpip, to simplify code that deals with
both IPv4 and IPv6 addresses.

Reorganised parts of tcpip.c and udp.c.

the TCP/IP protocol suite (rather than being general transport-layer
functions).

if the application wants to send data then it will have to use the normal
senddata() mechanism.

all servers.

there doing nothing when it's actually waiting for a DHCP reply.

concept demo that actually does something useful.

Parameter request list is yet another option that ISC dhcpd ignores
unless it's in the main options block.

Fix logic error in parsing file and sname fields.

default test to the DHCP test.

Added test code to configure the interface for IPv4 after DHCP.

cycle.  :)

doesn't seem to be required by the RFCs, but at least ISC dhcpd and
ethereal refuse to recognise it otherwise.

packets.