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author | Alexei Starovoitov <ast@plumgrid.com> | 2014-12-01 15:06:36 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2014-12-05 21:47:32 -0800 |
commit | 03f4723ed7a52bd31da26eefe2cdde563ea0f468 (patch) | |
tree | 4a3f1b2427c8bf1f2e86f4f1e842a32c5602b621 /samples/uhid | |
parent | 89aa075832b0da4402acebd698d0411dcc82d03e (diff) |
samples: bpf: example of stateful socket filtering
this socket filter example does:
- creates arraymap in kernel with key 4 bytes and value 8 bytes
- loads eBPF program which assumes that packet is IPv4 and loads one byte of
IP->proto from the packet and uses it as a key in a map
r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)];
*(u32*)(fp - 4) = r0;
value = bpf_map_lookup_elem(map_fd, fp - 4);
if (value)
(*(u64*)value) += 1;
- attaches this program to raw socket
- every second user space reads map[IPPROTO_TCP], map[IPPROTO_UDP], map[IPPROTO_ICMP]
to see how many packets of given protocol were seen on loopback interface
Usage:
$sudo samples/bpf/sock_example
TCP 0 UDP 0 ICMP 0 packets
TCP 187600 UDP 0 ICMP 4 packets
TCP 376504 UDP 0 ICMP 8 packets
TCP 563116 UDP 0 ICMP 12 packets
TCP 753144 UDP 0 ICMP 16 packets
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/uhid')
0 files changed, 0 insertions, 0 deletions