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KFunc bpf_dynptr_adjust

v6.5

Adjusts the dynptr to reflect the new [start, end) interval.

Definition

It advances the offset of the dynptr by start bytes, and if end is less than the size of the dynptr, then this will trim the dynptr accordingly.

int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end)

Usage

Adjusting the dynptr interval may be useful in certain situations. For example, when hashing which takes in generic dynptrs, if the dynptr points to a struct but only a certain memory region inside the struct should be hashed, adjust can be used to narrow in on the specific region to hash.

Program types

The following program types can make use of this kfunc:

Example

Docs could be improved

This part of the docs is incomplete, contributions are very welcome