samples: bpf: large eBPF program in C

sockex2_kern.c is purposefully large eBPF program in C.
llvm compiles ~200 lines of C code into ~300 eBPF instructions.

It's similar to __skb_flow_dissect() to demonstrate that complex packet parsing
can be done by eBPF.
Then it uses (struct flow_keys)->dst IP address (or hash of ipv6 dst) to keep
stats of number of packets per IP.
User space loads eBPF program, attaches it to loopback interface and prints
dest_ip->#packets stats every second.

Usage:
$sudo samples/bpf/sockex2
ip 127.0.0.1 count 19
ip 127.0.0.1 count 178115
ip 127.0.0.1 count 369437
ip 127.0.0.1 count 559841
ip 127.0.0.1 count 750539

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 770d145186c3..b5b3600dcdf5 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -5,20 +5,24 @@ obj- := dummy.o
 hostprogs-y := test_verifier test_maps
 hostprogs-y += sock_example
 hostprogs-y += sockex1
+hostprogs-y += sockex2
 
 test_verifier-objs := test_verifier.o libbpf.o
 test_maps-objs := test_maps.o libbpf.o
 sock_example-objs := sock_example.o libbpf.o
 sockex1-objs := bpf_load.o libbpf.o sockex1_user.o
+sockex2-objs := bpf_load.o libbpf.o sockex2_user.o
 
 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
 always += sockex1_kern.o
+always += sockex2_kern.o
 
 HOSTCFLAGS += -I$(objtree)/usr/include
 
 HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
 HOSTLOADLIBES_sockex1 += -lelf
+HOSTLOADLIBES_sockex2 += -lelf
 
 # point this to your LLVM backend with bpf support
 LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc