From: Viswanath Krishnamurthy <viswa.krish@gmail.com>

The current ipv4 incorrectly checks the IP address for multicast address.
This causes valid IPv4 unicast address to be trated as multicast address

For e.g if the PXE/tftp server IP address is 192.168.4.XXX where XXX is
224 or greater, it gets treated as multicast address and a ethernet
multicast address is sent out on the wire causing timeouts

Allow for settings to be described by something other than a DHCP option
tag if desirable.  Currently used only for the MAC address setting.

Separate out fake DHCP packet creation code from dhcp.c to fakedhcp.c.

Remove notion of settings from dhcppkt.c.

Rationalise dhcp.c to use settings API only for final registration of the
DHCP options, rather than using {store,fetch}_setting throughout.

structures.

DHCP still broken and #if 0'd out.

Achieved via Perl using:

perl -pi -e 's/pk_buff/io_buffer/g; s/Packet buffer/I\/O buffer/ig; ' \
	-e 's/pkbuff\.h/iobuf.h/g; s/pkb_/iob_/g; s/_pkb/_iob/g; ' \
	-e 's/pkb/iobuf/g; s/PKB/IOB/g;'

it as a fallback network device rather than an explicitly forced network
device.

Clear routing table entries before re-attempting DHCP.

retrying".

transmissions.

Simplify checksum generation on the TX datapath.

Move routing into a separate function

stripping the header.  Also fix an htons/ntohs confusion.

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.

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).

we are constructing the IP header ourselves.

Formatting fix-ups (80 column limit is mandatory!)

transition away from uIP.

Prepared ipv4.c for transition away from uIP.

Kill off the static single net device and move to proper dynamic
registration (which we need with the new device model).

Break the (flawed) assumption that all network-layer protocols can use
ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP
protocol using ARP_NET_PROTOCOL() and provide a single method for checking
the existence of a local network-layer address.