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  1. 14 12月, 2016 1 次提交
  3. 04 12月, 2016 1 次提交
    • A
      netlink: 2-clause nla_ok() · 4f7df337
      由 Alexey Dobriyan 提交于 
      nla_ok() consists of 3 clauses:

	1) int rem >= (int)sizeof(struct nlattr)

	2) u16 nla_len >= sizeof(struct nlattr)

	3) u16 nla_len <= int rem

The statement is that clause (1) is redundant.

What it does is ensuring that "rem" is a positive number,
so that in clause (3) positive number will be compared to positive number
with no problems.

However, "u16" fully fits into "int" and integers do not change value
when upcasting even to signed type. Negative integers will be rejected
by clause (3) just fine. Small positive integers will be rejected
by transitivity of comparison operator.

NOTE: all of the above DOES NOT apply to nlmsg_ok() where ->nlmsg_len is
u32(!), so 3 clauses AND A CAST TO INT are necessary.

Obligatory space savings report: -1.6 KB

	$ ./scripts/bloat-o-meter ../vmlinux-000* ../vmlinux-001*
	add/remove: 0/0 grow/shrink: 3/63 up/down: 35/-1692 (-1657)
	function                                     old     new   delta
	validate_scan_freqs                          142     155     +13
	tcf_em_tree_validate                         867     879     +12
	dcbnl_ieee_del                               328     338     +10
	netlbl_cipsov4_add_common.isra               218     215      -3
		...
	ovs_nla_put_actions                          888     806     -82
	netlbl_cipsov4_add_std                      1648    1566     -82
	nl80211_parse_sched_scan                    2889    2780    -109
	ip_tun_from_nlattr                          3086    2945    -141
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4f7df337
  5. 20 11月, 2016 1 次提交
    • A
      netlink: use "unsigned int" in nla_next() · 3b2c75d3
      由 Alexey Dobriyan 提交于 
      ->nla_len is unsigned entity (it's length after all) and u16,
thus it can't overflow when being aligned into int/unsigned int.

(nlmsg_next has the same code, but I didn't yet convince myself
it is correct to do so).

There is pointer arithmetic in this function and offset being
unsigned is better:

	add/remove: 0/0 grow/shrink: 1/64 up/down: 5/-309 (-304)
	function                                     old     new   delta
	nl80211_set_wiphy                           1444    1449      +5
	team_nl_cmd_options_set                      997     995      -2
	tcf_em_tree_validate                         872     870      -2
	switchdev_port_bridge_setlink                352     350      -2
	switchdev_port_br_afspec                     312     310      -2
	rtm_to_fib_config                            428     426      -2
	qla4xxx_sysfs_ddb_set_param                 2193    2191      -2
	qla4xxx_iface_set_param                     4470    4468      -2
	ovs_nla_free_flow_actions                    152     150      -2
	output_userspace                             518     516      -2
		...
	nl80211_set_reg                              654     649      -5
	validate_scan_freqs                          148     142      -6
	validate_linkmsg                             288     282      -6
	nl80211_parse_connkeys                       489     483      -6
	nlattr_set                                   231     224      -7
	nf_tables_delsetelem                         267     260      -7
	do_setlink                                  3416    3408      -8
	netlbl_cipsov4_add_std                      1672    1659     -13
	nl80211_parse_sched_scan                    2902    2888     -14
	nl80211_trigger_scan                        1738    1720     -18
	do_execute_actions                          2821    2738     -83
	Total: Before=154865355, After=154865051, chg -0.00%
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3b2c75d3
  7. 30 10月, 2016 1 次提交
  9. 17 5月, 2016 1 次提交
  11. 24 4月, 2016 6 次提交
  13. 22 4月, 2016 1 次提交
  15. 21 4月, 2016 1 次提交
  17. 20 4月, 2016 2 次提交
  19. 30 9月, 2015 1 次提交
  21. 01 4月, 2015 2 次提交
  23. 18 1月, 2015 1 次提交
    • J
      netlink: make nlmsg_end() and genlmsg_end() void · 053c095a
      由 Johannes Berg 提交于 
      Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.

This makes the very common pattern of

  if (genlmsg_end(...) < 0) { ... }

be a whole bunch of dead code. Many places also simply do

  return nlmsg_end(...);

and the caller is expected to deal with it.

This also commonly (at least for me) causes errors, because it is very
common to write

  if (my_function(...))
    /* error condition */

and if my_function() does "return nlmsg_end()" this is of course wrong.

Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.

Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did

-	return nlmsg_end(...);
+	nlmsg_end(...);
+	return 0;

I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.

One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      053c095a
  25. 06 1月, 2015 1 次提交
  27. 29 10月, 2014 1 次提交
  29. 17 10月, 2014 1 次提交
  31. 29 7月, 2014 1 次提交
  33. 22 9月, 2013 1 次提交
  35. 11 9月, 2012 1 次提交
  37. 04 8月, 2012 1 次提交
  39. 02 4月, 2012 4 次提交
  41. 31 1月, 2012 1 次提交
  43. 05 11月, 2011 1 次提交
  45. 23 6月, 2011 1 次提交
    • J
      netlink: advertise incomplete dumps · 670dc283
      由 Johannes Berg 提交于 
      Consider the following situation:
 * a dump that would show 8 entries, four in the first
   round, and four in the second
 * between the first and second rounds, 6 entries are
   removed
 * now the second round will not show any entry, and
   even if there is a sequence/generation counter the
   application will not know

To solve this problem, add a new flag NLM_F_DUMP_INTR
to the netlink header that indicates the dump wasn't
consistent, this flag can also be set on the MSG_DONE
message that terminates the dump, and as such above
situation can be detected.

To achieve this, add a sequence counter to the netlink
callback struct. Of course, netlink code still needs
to use this new functionality. The correct way to do
that is to always set cb->seq when a dumpit callback
is invoked and call nl_dump_check_consistent() for
each new message. The core code will also call this
function for the final MSG_DONE message.

To make it usable with generic netlink, a new function
genlmsg_nlhdr() is needed to obtain the netlink header
from the genetlink user header.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
      670dc283
  47. 10 5月, 2011 1 次提交
  49. 01 2月, 2011 1 次提交
  51. 17 11月, 2010 1 次提交
  53. 05 11月, 2010 1 次提交
  55. 24 6月, 2010 1 次提交
  57. 20 3月, 2010 1 次提交
  59. 19 2月, 2010 1 次提交