KFunc bpf_dynptr_adjust
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(const struct bpf_dynptr *p, 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:
BPF_PROG_TYPE_CGROUP_SKBBPF_PROG_TYPE_CGROUP_SOCK_ADDRBPF_PROG_TYPE_LSMBPF_PROG_TYPE_LWT_INBPF_PROG_TYPE_LWT_OUTBPF_PROG_TYPE_LWT_SEG6LOCALBPF_PROG_TYPE_LWT_XMITBPF_PROG_TYPE_NETFILTERBPF_PROG_TYPE_SCHED_ACTBPF_PROG_TYPE_SCHED_CLSBPF_PROG_TYPE_SK_SKBBPF_PROG_TYPE_SOCKET_FILTERBPF_PROG_TYPE_STRUCT_OPSBPF_PROG_TYPE_SYSCALLBPF_PROG_TYPE_TRACINGBPF_PROG_TYPE_XDP
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome