linux/drivers/net/ppp
Eric Dumazet 73f156a6e8 inetpeer: get rid of ip_id_count
Ideally, we would need to generate IP ID using a per destination IP
generator.

linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.

1) each inet_peer struct consumes 192 bytes

2) inetpeer cache uses a binary tree of inet_peer structs,
   with a nominal size of ~66000 elements under load.

3) lookups in this tree are hitting a lot of cache lines, as tree depth
   is about 20.

4) If server deals with many tcp flows, we have a high probability of
   not finding the inet_peer, allocating a fresh one, inserting it in
   the tree with same initial ip_id_count, (cf secure_ip_id())

5) We garbage collect inet_peer aggressively.

IP ID generation do not have to be 'perfect'

Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.

We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.

ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)

secure_ip_id() and secure_ipv6_id() no longer are needed.

Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-02 11:00:41 -07:00
..
bsd_comp.c
Kconfig tty/serial patches for 3.9-rc1 2013-02-21 13:41:04 -08:00
Makefile
ppp_async.c tty: Fix recursive deadlock in tty_perform_flush() 2013-03-18 16:52:24 -07:00
ppp_deflate.c ppp: Change copyright notices from ANU to me 2012-03-04 20:41:38 -05:00
ppp_generic.c net: filter: let unattached filters use sock_fprog_kern 2014-05-23 16:48:05 -04:00
ppp_mppe.c drivers/net/*: Fix FSF address in file headers 2013-12-06 12:37:55 -05:00
ppp_mppe.h
ppp_synctty.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
pppoe.c ppp: slight optimization of addr compare 2013-12-26 13:31:33 -05:00
pppox.c ppp: Replace uses of <linux/if_ppp.h> with <linux/ppp-ioctl.h> 2012-03-04 20:41:38 -05:00
pptp.c inetpeer: get rid of ip_id_count 2014-06-02 11:00:41 -07:00