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  1. 02 Mar, 2019 10 commits
    • Stanislav Fomichev's avatar
      selftests: bpf: break up test_progs - pkt access · 7395724b
      Stanislav Fomichev authored 
      Move pkt access prog tests into separate files.
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      7395724b
    • Stanislav Fomichev's avatar
      selftests: bpf: break up test_progs - preparations · 3f306588
      Stanislav Fomichev authored 
      Add new prog_tests directory where tests are supposed to land.
Each prog_tests/<filename>.c is expected to have a global function
with signature 'void test_<filename>(void)'. Makefile automatically
generates prog_tests/tests.h file with entry for each prog_tests file:

	#ifdef DECLARE
	extern void test_<filename>(void);
	...
	#endif

	#ifdef CALL
	test_<filename>();
	...
	#endif

prog_tests/tests.h is included in test_progs.c in two places with
appropriate defines. This scheme allows us to move each function with
a separate patch without breaking anything.

Compared to the recent verifier split, each separate file here is
a compilation unit and test_progs.[ch] is now used as a place to put
some common routines that might be used by multiple tests.
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      3f306588
    • Alexei Starovoitov's avatar
      Merge branch 'bpf_skb_ecn_set_ce' · 0d7f6827
      Alexei Starovoitov authored 
      Lawrence Brakmo says:

====================
Host Bandwidth Manager is a framework for limiting the bandwidth used
by v2 cgroups. It consists of 1 BPF helper, a sample BPF program to
limit egress bandwdith as well as a sample user program and script to
simplify HBM testing.

The sample HBM BPF program is not meant to be production quality, it is
provided as proof of concept. A lot more information, including sample
runs in some cases, are provided in the commit messages of the individual
patches.

A future patch will add support for reducing TCP's cwnd (we are evaluating
alternatives). Another patch will add support for fair queueing's Earliest
Departure Time. Until then, HBM is better suited for flows supporitng ECN.

In addition, A BPF program to limit ingress bandwidth will be provided in
an upcomming patchset.

Changes from v1 to v2:
  * bpf_tcp_enter_cwr can only be called from a cgroup skb egress BPF
    program (otherwise load or attach will fail) where we already hold
    the sk lock. Also only applies for ESTABLISHED state.
  * bpf_skb_ecn_set_ce uses INET_ECN_set_ce()
  * bpf_tcp_check_probe_timer now uses tcp_reset_xmit_timer. Can only be
    used by egress cgroup skb programs.
  * removed load_cg_skb user program.
  * nrm bpf egress program checks packet header in skb to determine
    ECN value. Now also works for ECN enabled UDP packets.
    Using ECN_ defines instead of integers.
  * NRM script test program now uses bpftool instead of load_cg_skb

Changes from v2 to v3:
  * Changed name from NRM (Network Resource Manager) to HBM (Host
    Bandwdith Manager)
  * The bpf helper to set ECN ce now checks that the header is writeable
  * Removed helper bpf functions that modified TCP state due to a concern
    about whether the socket is locked by the current thread.
====================
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      0d7f6827
    • brakmo's avatar
      bpf: HBM test script · 4ffd44cf
      brakmo authored 
      Script for testing HBM (Host Bandwidth Manager) framework.
It creates a cgroup to use for testing and load a BPF program to limit
egress bandwidht. It then uses iperf3 or netperf to create
loads. The output is the goodput in Mbps (unless -D is used).

It can work on a single host using loopback or among two hosts (with netperf).
When using loopback, it is recommended to also introduce a delay of at least
1ms (-d=1), otherwise the assigned bandwidth is likely to be underutilized.

USAGE: $name [out] [-b=<prog>|--bpf=<prog>] [-c=<cc>|--cc=<cc>] [-D]
             [-d=<delay>|--delay=<delay>] [--debug] [-E]
             [-f=<#flows>|--flows=<#flows>] [-h] [-i=<id>|--id=<id >] [-l]
	     [-N] [-p=<port>|--port=<port>] [-P] [-q=<qdisc>]
             [-R] [-s=<server>|--server=<server] [--stats]
	     [-t=<time>|--time=<time>] [-w] [cubic|dctcp]
  Where:
    out               Egress (default egress)
    -b or --bpf       BPF program filename to load and attach.
                      Default is nrm_out_kern.o for egress,
    -c or -cc         TCP congestion control (cubic or dctcp)
    -d or --delay     Add a delay in ms using netem
    -D                In addition to the goodput in Mbps, it also outputs
                      other detailed information. This information is
                      test dependent (i.e. iperf3 or netperf).
    --debug           Print BPF trace buffer
    -E                Enable ECN (not required for dctcp)
    -f or --flows     Number of concurrent flows (default=1)
    -i or --id        cgroup id (an integer, default is 1)
    -l                Do not limit flows using loopback
    -N                Use netperf instead of iperf3
    -h                Help
    -p or --port      iperf3 port (default is 5201)
    -P                Use an iperf3 instance for each flow
    -q                Use the specified qdisc.
    -r or --rate      Rate in Mbps (default 1s 1Gbps)
    -R                Use TCP_RR for netperf. 1st flow has req
                      size of 10KB, rest of 1MB. Reply in all
                      cases is 1 byte.
                      More detailed output for each flow can be found
                      in the files netperf.<cg>.<flow>, where <cg> is the
                      cgroup id as specified with the -i flag, and <flow>
                      is the flow id starting at 1 and increasing by 1 for
                      flow (as specified by -f).
    -s or --server    hostname of netperf server. Used to create netperf
                      test traffic between to hosts (default is within host)
                      netserver must be running on the host.
    --stats           Get HBM stats (marked, dropped, etc.)
    -t or --time      duration of iperf3 in seconds (default=5)
    -w                Work conserving flag. cgroup can increase its
                      bandwidth beyond the rate limit specified
                      while there is available bandwidth. Current
                      implementation assumes there is only one NIC
                      (eth0), but can be extended to support multiple
                      NICs. This is just a proof of concept.
    cubic or dctcp    specify TCP CC to use

Examples:
 ./do_hbm_test.sh -l -d=1 -D --stats
     Runs a 5 second test, using a single iperf3 flow and with the default
     rate limit of 1Gbps and a delay of 1ms (using netem) using the default
     TCP congestion control on the loopback device (hence we use "-l" to
     enforce bandwidth limit on loopback device). Since no direction is
     specified, it defaults to egress. Since no TCP CC algorithm is
     specified it uses the system default (Cubic for this test).
     With no -D flag, only the value of the AGGREGATE OUTPUT would show.
     id refers to the cgroup id and is useful when running multi cgroup
     tests (supported by a future patch).
     This patchset does not support calling TCP's congesion window
     reduction, even when packets are dropped by the BPF program, resulting
     in a large number of packets dropped. It is recommended that the  current
     HBM implemenation only be used with ECN enabled flows. A future patch
     will add support for reducing TCP's cwnd and will increase the
     performance of non-ECN enabled flows.
   Output:
     Details for HBM in cgroup 1
     id:1
     rate_mbps:493
     duration:4.8 secs
     packets:11355
     bytes_MB:590
     pkts_dropped:4497
     bytes_dropped_MB:292
     pkts_marked_percent: 39.60
     bytes_marked_percent: 49.49
     pkts_dropped_percent: 39.60
     bytes_dropped_percent: 49.49
     PING AVG DELAY:2.075
     AGGREGATE_GOODPUT:505

./do_nrm_test.sh -l -d=1 -D --stats dctcp
     Same as above but using dctcp. Note that fewer bytes are dropped
     (0.01% vs. 49%).
   Output:
     Details for HBM in cgroup 1
     id:1
     rate_mbps:945
     duration:4.9 secs
     packets:16859
     bytes_MB:578
     pkts_dropped:1
     bytes_dropped_MB:0
     pkts_marked_percent: 28.74
     bytes_marked_percent: 45.15
     pkts_dropped_percent:  0.01
     bytes_dropped_percent:  0.01
     PING AVG DELAY:2.083
     AGGREGATE_GOODPUT:965

./do_nrm_test.sh -d=1 -D --stats
     As first example, but without limiting loopback device (i.e. no
     "-l" flag). Since there is no bandwidth limiting, no details for
     HBM are printed out.
   Output:
     Details for HBM in cgroup 1
     PING AVG DELAY:2.019
     AGGREGATE_GOODPUT:42655

./do_hbm.sh -l -d=1 -D --stats -f=2
     Uses iper3 and does 2 flows
./do_hbm.sh -l -d=1 -D --stats -f=4 -P
     Uses iperf3 and does 4 flows, each flow as a separate process.
./do_hbm.sh -l -d=1 -D --stats -f=4 -N
     Uses netperf, 4 flows
./do_hbm.sh -f=1 -r=2000 -t=5 -N -D --stats dctcp -s=<server-name>
     Uses netperf between two hosts. The remote host name is specified
     with -s= and you need to start the program netserver manually on
     the remote host. It will use 1 flow, a rate limit of 2Gbps and dctcp.
./do_hbm.sh -f=1 -r=2000 -t=5 -N -D --stats -w dctcp \
     -s=<server-name>
     As previous, but allows use of extra bandwidth. For this test the
     rate is 8Gbps vs. 1Gbps of the previous test.
Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      4ffd44cf
    • brakmo's avatar
      bpf: User program for testing HBM · a1270fe9
      brakmo authored 
      The program nrm creates a cgroup and attaches a BPF program to the
cgroup for testing HBM (Host Bandwidth Manager) for egress traffic.
One still needs to create network traffic. This can be done through
netesto, netperf or iperf3.
A follow-up patch contains a script to create traffic.

USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>]
           [-w] [-h] [prog]
  Where:
   -d        Print BPF trace debug buffer
   -l        Also limit flows doing loopback
   -n <#>    To create cgroup "/hbm#" and attach prog. Default is /nrm1
             This is convenient when testing HBM in more than 1 cgroup
   -r <rate> Rate limit in Mbps
   -s        Get HBM stats (marked, dropped, etc.)
   -t <time> Exit after specified seconds (deault is 0)
   -w        Work conserving flag. cgroup can increase its bandwidth
             beyond the rate limit specified while there is available
             bandwidth. Current implementation assumes there is only
             NIC (eth0), but can be extended to support multiple NICs.
             Currrently only supported for egress. Note, this is just
	     a proof of concept.
   -h        Print this info
   prog      BPF program file name. Name defaults to hbm_out_kern.o

More information about HBM can be found in the paper "BPF Host Resource
Management" presented at the 2018 Linux Plumbers Conference, Networking Track
(http://vger.kernel.org/lpc_net2018_talks/LPC%20BPF%20Network%20Resource%20Paper.pdf)
Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      a1270fe9
    • brakmo's avatar
      bpf: Sample HBM BPF program to limit egress bw · 187d0738
      brakmo authored 
      A cgroup skb BPF program to limit cgroup output bandwidth.
It uses a modified virtual token bucket queue to limit average
egress bandwidth. The implementation uses credits instead of tokens.
Negative credits imply that queueing would have happened (this is
a virtual queue, so no queueing is done by it. However, queueing may
occur at the actual qdisc (which is not used for rate limiting).

This implementation uses 3 thresholds, one to start marking packets and
the other two to drop packets:
                                 CREDIT
       - <--------------------------|------------------------> +
             |    |          |      0
             |  Large pkt    |
             |  drop thresh  |
  Small pkt drop             Mark threshold
      thresh

The effect of marking depends on the type of packet:
a) If the packet is ECN enabled, then the packet is ECN ce marked.
   The current mark threshold is tuned for DCTCP.
c) Else, it is dropped if it is a large packet.

If the credit is below the drop threshold, the packet is dropped.
Note that dropping a packet through the BPF program does not trigger CWR
(Congestion Window Reduction) in TCP packets. A future patch will add
support for triggering CWR.

This BPF program actually uses 2 drop thresholds, one threshold
for larger packets (>= 120 bytes) and another for smaller packets. This
protects smaller packets such as SYNs, ACKs, etc.

The default bandwidth limit is set at 1Gbps but this can be changed by
a user program through a shared BPF map. In addition, by default this BPF
program does not limit connections using loopback. This behavior can be
overwritten by the user program. There is also an option to calculate
some statistics, such as percent of packets marked or dropped, which
the user program can access.

A latter patch provides such a program (hbm.c)
Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      187d0738
    • brakmo's avatar
      bpf: sync bpf.h to tools and update bpf_helpers.h · 5cce85c6
      brakmo authored 
      This patch syncs the uapi bpf.h to tools/ and also updates
bpf_herlpers.h in tools/
Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      5cce85c6
    • brakmo's avatar
      bpf: add bpf helper bpf_skb_ecn_set_ce · f7c917ba
      brakmo authored 
      This patch adds a new bpf helper BPF_FUNC_skb_ecn_set_ce
"int bpf_skb_ecn_set_ce(struct sk_buff *skb)". It is added to
BPF_PROG_TYPE_CGROUP_SKB typed bpf_prog which currently can
be attached to the ingress and egress path. The helper is needed
because his type of bpf_prog cannot modify the skb directly.

This helper is used to set the ECN field of ECN capable IP packets to ce
(congestion encountered) in the IPv6 or IPv4 header of the skb. It can be
used by a bpf_prog to manage egress or ingress network bandwdith limit
per cgroupv2 by inducing an ECN response in the TCP sender.
This works best when using DCTCP.
Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      f7c917ba
    • Yonghong Song's avatar
      samples/bpf: silence compiler warning for xdpsock_user.c · b74e21ab
      Yonghong Song authored 
      Compiling xdpsock_user.c with 4.8.5, I hit the following
compilation warning:
    HOSTCC  samples/bpf/xdpsock_user.o
  /data/users/yhs/work/net-next/samples/bpf/xdpsock_user.c: In function ‘main’:
  /data/users/yhs/work/net-next/samples/bpf/xdpsock_user.c:449:6: warning: ‘idx_cq’ may be used unini
  tialized in this function [-Wmaybe-uninitialized]
    u32 idx_cq, idx_fq;
        ^
  /data/users/yhs/work/net-next/samples/bpf/xdpsock_user.c:606:7: warning: ‘idx_rx’ may be used unini
  tialized in this function [-Wmaybe-uninitialized]
     u32 idx_rx, idx_tx = 0;
         ^
  /data/users/yhs/work/net-next/samples/bpf/xdpsock_user.c:506:6: warning: ‘idx_rx’ may be used unini
  tialized in this function [-Wmaybe-uninitialized]
    u32 idx_rx, idx_fq = 0;

As an example, the code pattern looks like:
    u32 idx_cq;
    ...
    ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq);
    if (ret) {
      ...
    }
    ... idx_fq ...
The compiler warns since it does not know whether &idx_fq is assigned
or not inside the library function xsk_ring_prod__reserve().

Let us assign an initial value 0 to such auto variables to silence
compiler warning.

Fixes: 248c7f9c ("samples/bpf: convert xdpsock to use libbpf for AF_XDP access")
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarJonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      b74e21ab
    • Yonghong Song's avatar
      selftests/bpf: set unlimited RLIMIT_MEMLOCK for test_sock_fields · a83de906
      Yonghong Song authored 
      This is to avoid permission denied error. A lot of systems
may have a much lower number, e.g., 64KB, for RLIMIT_MEMLOCK,
which may not be sufficient for the test to run successfully.

Fixes: e0b27b3f ("bpf: Add test_sock_fields for skb->sk and bpf_tcp_sock")
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      a83de906
  3. 01 Mar, 2019 11 commits
  5. 28 Feb, 2019 13 commits
  7. 27 Feb, 2019 6 commits
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