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authorJohn Fastabend <john.fastabend@gmail.com>2018-10-19 19:56:49 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-10-20 21:37:11 +0200
commit6fff607e2f14bd7c63c06c464a6f93b8efbabe28 (patch)
tree3ac21ecddcd5903aa5eaecb5ba54d2434ccf5184 /tools
parent5032d079909d1ac5c2535acc32d5f01cd245d8ea (diff)
bpf: sk_msg program helper bpf_msg_push_data
This allows user to push data into a msg using sk_msg program types. The format is as follows, bpf_msg_push_data(msg, offset, len, flags) this will insert 'len' bytes at offset 'offset'. For example to prepend 10 bytes at the front of the message the user can, bpf_msg_push_data(msg, 0, 10, 0); This will invalidate data bounds so BPF user will have to then recheck data bounds after calling this. After this the msg size will have been updated and the user is free to write into the added bytes. We allow any offset/len as long as it is within the (data, data_end) range. However, a copy will be required if the ring is full and its possible for the helper to fail with ENOMEM or EINVAL errors which need to be handled by the BPF program. This can be used similar to XDP metadata to pass data between sk_msg layer and lower layers. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
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