Some of the sample files are causing issues when they are loaded with tc
and cls_bpf, meaning tc bails out while trying to parse the resulting ELF
file as program/map/etc sections are not present, which can be easily
spotted with readelf(1).
Currently, BPF samples are including some of the kernel headers and mid
term we should change them to refrain from this, really. When dynamic
debugging is enabled, we bail out due to undeclared KBUILD_MODNAME, which
is easily overlooked in the build as clang spills this along with other
noisy warnings from various header includes, and llc still generates an
ELF file with mentioned characteristics. For just playing around with BPF
examples, this can be a bit of a hurdle to take.
Just add a fake KBUILD_MODNAME as a band-aid to fix the issue, same is
done in xdp*_kern samples already.
Fixes: 65d472fb00 ("samples/bpf: add 'pointer to packet' tests")
Fixes: 6afb1e28b8 ("samples/bpf: Add tunnel set/get tests.")
Fixes: a3f7461734 ("cgroup: bpf: Add an example to do cgroup checking in BPF")
Reported-by: Chandrasekar Kannan <ckannan@console.to>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
parse_simple.c - packet parser exapmle with single length check that
filters out udp packets for port 9
parse_varlen.c - variable length parser that understand multiple vlan headers,
ipip, ipip6 and ip options to filter out udp or tcp packets on port 9.
The packet is parsed layer by layer with multitple length checks.
parse_ldabs.c - classic style of packet parsing using LD_ABS instruction.
Same functionality as parse_simple.
simple = 24.1Mpps per core
varlen = 22.7Mpps
ldabs = 21.4Mpps
Parser with LD_ABS instructions is slower than full direct access parser
which does more packet accesses and checks.
These examples demonstrate the choice bpf program authors can make between
flexibility of the parser vs speed.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Borkmann