Such an assignment in two parts (first deref in `unsafe`, then field
access outside of `unsafe`) is bogus: the deref "returned" by the
`unsafe` block actually creates a copy of the `__sk_buff` struct because
it implements `Copy`. The mark value is written to the `mark` field of
the copy, and not the real `__sk_buff`.
Change it to do it all in the `unsafe` block.
The same is done for the `.len()` getter to avoid copying the whole
`__sk_buff` struct for a 32 bit field. Although such a copy should be
optimized out by the compiler, it's better to help it do so.
This change separates the previous `SkBuffContext` into three structs:
* `SkBuff` which is a wrapper around `__sk_buff` which contains all
possible methods operating on it.
* `SkBuffContext` which is a program context for programs which
**cannot** access `__sk_buff` directly and instead can only use
`load_bytes`.
* `TcContext` which is a classifier context which can access `__sk_buff`
directly, hence exposes `data` and `data_end`.
Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>
The pull_data method is used to ensure that all the required bytes
are available in the linear portion of the skb.
Signed-off-by: Hengqi Chen <chenhengqi@outlook.com>
This change exposes the BPF helper bpf_socket_get_uid as a public method
of SkBuffContext, which allows to get the owner UID of the socket
associated to the sk_buff stored in the context.
Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>
This is necessary since the context is used in many other program types
and not just in SK_SKB programs.
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
Alessandro Decina
Tuetuopay
Michal Rostecki
Hengqi Chen
tirex
Dave Tucker