Clarified packet ownership transfer between a few functions.
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.
Remove unused attribute from __table macros; the tables are no longer
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.
Make the UDP senddata() methods return a status code.
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 UDP implementation to use the new Etherboot UDP API.
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.)
Split DHCP packet creation into two parts: creating the basic packet
structure, and populating it with options. This should allow us to
use the same basic options list for both DHCPDISCOVER and DHCPREQUEST,
plus making it much easier to set the non-constant parameters
(e.g. requested IP address) in request packets.
Allow for calling find_dhcp_option() with "options" set to NULL, in order
to search through all registered option blocks.
Move some static inlines that are likely to be used frequently into
dhcpopts.c as normal functions, to save space.
Add sketch code to reassemble a DHCP packet from our internal "everything
is a DHCP option" data structures.
We need this code in order to be able to return a DHCP packet to a PXE NBP
which reflects options from our multiple sources (e.g. NVS and DHCP
server). This is expensive, but necessary. Having paid this cost, we may
as well try to use the same code to generate our DHCP request packets,
since the process is similar.