Recently we added SKBMOD_F_ECN option support to the kernel; support it in
the tc-skbmod(8) front end, and update its man page accordingly.
The 2 least significant bits of the Traffic Class field in IPv4 and IPv6
headers are used to represent different ECN states [1]:
0b00: "Non ECN-Capable Transport", Non-ECT
0b10: "ECN Capable Transport", ECT(0)
0b01: "ECN Capable Transport", ECT(1)
0b11: "Congestion Encountered", CE
This new option, "ecn", marks ECT(0) and ECT(1) IPv{4,6} packets as CE,
which is useful for ECN-based rate limiting. For example:
$ tc filter add dev eth0 parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action skbmod \
ecn
The updated tc-skbmod SYNOPSIS looks like the following:
tc ... action skbmod { set SETTABLE | swap SWAPPABLE | ecn } ...
Only one of "set", "swap" or "ecn" shall be used in a single tc-skbmod
command. Trying to use more than one of them at a time is considered
undefined behavior; pipe multiple tc-skbmod commands together instead.
"set" and "swap" only affect Ethernet packets, while "ecn" only affects
IP packets.
Depends on kernel patch "net/sched: act_skbmod: Add SKBMOD_F_ECN option
support", as well as iproute2 patch "tc/skbmod: Remove misinformation
about the swap action".
[1] https://en.wikipedia.org/wiki/Explicit_Congestion_Notification
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Currently man 8 tc-skbmod says that "...the swap action will occur after
any smac/dmac substitutions are executed, if they are present."
This is false. In fact, trying to "set" and "swap" in a single skbmod
command causes the "set" part to be completely ignored. As an example:
$ tc filter add dev eth0 parent 1: protocol ip prio 10 \
matchall action skbmod \
set dmac AA:AA:AA:AA:AA:AA smac BB:BB:BB:BB:BB:BB \
swap mac
The above command simply does a "swap", without setting DMAC or SMAC to
AA's or BB's. The root cause of this is in the kernel, see
net/sched/act_skbmod.c:tcf_skbmod_init():
parm = nla_data(tb[TCA_SKBMOD_PARMS]);
index = parm->index;
if (parm->flags & SKBMOD_F_SWAPMAC)
lflags = SKBMOD_F_SWAPMAC;
^^^^^^^^^^^^^^^^^^^^^^^^^^
Doing a "=" instead of "|=" clears all other "set" flags when doing a
"swap". Discourage using "set" and "swap" in the same command by
documenting it as undefined behavior, and update the "SYNOPSIS" section
as well as tc -help text accordingly.
If one really needs to e.g. "set" DMAC to all AA's then "swap" DMAC and
SMAC, one should do two separate commands and "pipe" them together.
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Modify implementations that return error from action_until->print_aopt()
callback to silently skip actions that don't have their corresponding
TCA_ACT_OPTIONS attribute set (some actions already behave like this).
Print action kind before returning from action_until->print_aopt()
callbacks. This is necessary to support terse dump mode in following patch
in the series.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Suggested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Many tc modules were printing error messages to stdout.
This is problematic if using JSON or other output formats.
Change all these places to use fprintf(stderr, ...) instead.
Also, remove unnecessary initialization and places
where else is used after error return.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Conflicts:
bridge/mdb.c
Updated bridge/bridge.c per removal of check_if_color_enabled by commit
1ca4341d2c ("color: disable color when json output is requested")
Signed-off-by: David Ahern <dsahern@gmail.com>
If the user didn't specify any control action, don't pop the command line
arguments: otherwise, parsing of the next argument (tipically the 'index'
keyword) results in an error, causing the following 'tc-testing' failures:
Test a6d6: Add skbedit action with index
Test 38f3: Delete skbedit action
Test a568: Add action with ife type
Test b983: Add action without ife type
Test 7d50: Add skbmod action to set destination mac
Test 9b29: Add skbmod action to set source mac
Test e93a: Delete an skbmod action
Also, add missing parse for 'ok' control action to m_police, to fix the
following 'tc-testing' failure:
Test 8dd5: Add police action with control ok
tested with:
# ./tdc.py
test results:
all tests ok using kernel 4.16-rc2, except 9aa8 "Get a single skbmod
action from a list" (which is failing also before this commit)
Fixes: 3572e01a09 ("tc: util: Don't call NEXT_ARG_FWD() in __parse_action_control()")
Cc: Michal Privoznik <mprivozn@redhat.com>
Cc: Wolfgang Bumiller <w.bumiller@proxmox.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
We have helper routines to support nested attribute addition into
netlink buffer: use them instead of open coding.
Use addattr_nest_compat()/addattr_nest_compat_end() where appropriate.
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Not all callers want parse_action_control*() to advance the
arguments. For instance act_parse_police() does the argument
advancing itself.
Fixes: e67aba5595 ("tc: actions: add helpers to parse and print control actions")
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Each tc action is terminated by a control action. Each action parses and
prints then intividually. Introduce set of helpers and allow to share
this code.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
This action is intended to be an upgrade from a usability perspective
from pedit (as well as operational debugability).
Compare this:
sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action pedit munge offset -14 u8 set 0x02 \
munge offset -13 u8 set 0x15 \
munge offset -12 u8 set 0x15 \
munge offset -11 u8 set 0x15 \
munge offset -10 u16 set 0x1515 \
pipe
to:
sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action skbmod dmac 02:15:15:15:15:15
Or worse, try to debug a policy with destination mac, source mac and
etherype. Then make that a hundred rules and you'll get my point.
The most important ethernet use case at the moment is when redirecting or
mirroring packets to a remote machine. The dst mac address needs a re-write
so that it doesn't get dropped or confuse an interconnecting (learning) switch
or dropped by a target machine (which looks at the dst mac).
In the future common use cases on pedit can be migrated to this action
(as an example different fields in ip v4/6, transports like tcp/udp/sctp
etc). For this first cut, this allows modifying basic ethernet header.
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Peilin Ye
Vlad Buslov
Stephen Hemminger
David Ahern
Davide Caratti
Serhey Popovych
Michal Privoznik
Jiri Pirko
Roman Mashak
Jamal Hadi Salim