filter.txt: update 'tools/net/' to 'tools/bpf/'

BPF engine and instruction set

------------------------------

Under tools/net/ there's a small helper tool called bpf_asm which can

Under tools/bpf/ there's a small helper tool called bpf_asm which can

be used to write low-level filters for example scenarios mentioned in the

previous section. Asm-like syntax mentioned here has been implemented in

bpf_asm and will be used for further explanations (instead of dealing with

In particular, as usage with xt_bpf or cls_bpf can result in more complex BPF

filters that might not be obvious at first, it's good to test filters before

attaching to a live system. For that purpose, there's a small tool called

bpf_dbg under tools/net/ in the kernel source directory. This debugger allows

bpf_dbg under tools/bpf/ in the kernel source directory. This debugger allows

for testing BPF filters against given pcap files, single stepping through the

BPF code on the pcap's packets and to do BPF machine register dumps.

[ 3389.935851] JIT code: 00000030: 00 e8 28 94 ff e0 83 f8 01 75 07 b8 ff ff 00 00

[ 3389.935852] JIT code: 00000040: eb 02 31 c0 c9 c3

In the kernel source tree under tools/net/, there's bpf_jit_disasm for

In the kernel source tree under tools/bpf/, there's bpf_jit_disasm for

generating disassembly out of the kernel log's hexdump:

# ./bpf_jit_disasm