kernel/linux.git/net/sched/sch_pie.c, branch linux-5.3.y

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 235

2019-06-19T15:09:07+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 53 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.904365654@linutronix.de Signed-off-by: Greg Kroah-Hartman

netlink: make validation more configurable for future strictness

2019-04-27T21:07:21+00:00

We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

netlink: make nla_nest_start() add NLA_F_NESTED flag

2019-04-27T21:03:44+00:00

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most netlink based interfaces (including recently added ones) are still not setting it in kernel generated messages. Without the flag, message parsers not aware of attribute semantics (e.g. wireshark dissector or libmnl's mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display the structure of their contents. Unfortunately we cannot just add the flag everywhere as there may be userspace applications which check nlattr::nla_type directly rather than through a helper masking out the flags. Therefore the patch renames nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start() as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually are rewritten to use nla_nest_start(). Except for changes in include/net/netlink.h, the patch was generated using this semantic patch: @@ expression E1, E2; @@ -nla_nest_start(E1, E2) +nla_nest_start_noflag(E1, E2) @@ expression E1, E2; @@ -nla_nest_start_noflag(E1, E2 | NLA_F_NESTED) +nla_nest_start(E1, E2) Signed-off-by: Michal Kubecek Acked-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

net: sched: pie: avoid slow division in drop probability decay

2019-02-28T18:35:41+00:00

As per RFC 8033, it is sufficient for the drop probability decay factor to have a value of (1 - 1/64) instead of 98%. This avoids the need to do slow division. Suggested-by: David Laight Signed-off-by: Leslie Monis Signed-off-by: David S. Miller

net: sched: pie: fix 64-bit division

2019-02-27T02:55:38+00:00

Use div_u64() to resolve build failures on 32-bit platforms. Fixes: 3f7ae5f3dc52 ("net: sched: pie: add more cases to auto-tune alpha and beta") Signed-off-by: Leslie Monis Reported-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: David S. Miller

net: sched: pie: fix mistake in reference link

2019-02-26T17:11:33+00:00

Fix the incorrect reference link to RFC 8033 Signed-off-by: Leslie Monis Signed-off-by: David S. Miller

net: sched: pie: update references

2019-02-25T22:21:03+00:00

RFC 8033 replaces the IETF draft for PIE Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis Acked-by: Dave Taht Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: pie: add derandomization mechanism

2019-02-25T22:21:03+00:00

Random dropping of packets to achieve latency control may introduce outlier situations where packets are dropped too close to each other or too far from each other. This can cause the real drop percentage to temporarily deviate from the intended drop probability. In certain scenarios, such as a small number of simultaneous TCP flows, these deviations can cause significant deviations in link utilization and queuing latency. RFC 8033 suggests using a derandomization mechanism to avoid these deviations. Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis Acked-by: Dave Taht Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: pie: add more cases to auto-tune alpha and beta

2019-02-25T22:21:03+00:00

The current implementation scales the local alpha and beta variables in the calculate_probability function by the same amount for all values of drop probability below 1%. RFC 8033 suggests using additional cases for auto-tuning alpha and beta when the drop probability is less than 1%. In order to add more auto-tuning cases, MAX_PROB must be scaled by u64 instead of u32 to prevent underflow when scaling the local alpha and beta variables in the calculate_probability function. Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis Acked-by: Dave Taht Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: pie: change initial value of pie_vars->burst_time

2019-02-25T22:21:03+00:00

RFC 8033 suggests an initial value of 150 milliseconds for the maximum time allowed for a burst of packets. Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis Acked-by: Dave Taht Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller