Helper function bpf_loop
Definition
Copyright (c) 2015 The Libbpf Authors. All rights reserved.
For nr_loops, call callback_fn function with callback_ctx as the context parameter. The callback_fn should be a static function and the callback_ctx should be a pointer to the stack. The flags is used to control certain aspects of the helper. Currently, the flags must be 0. Currently, nr_loops is limited to 1 << 23 (~8 million) loops.
long (_callback_fn)(u32 index, void _ctx);
where index is the current index in the loop. The index is zero-indexed.
If callback_fn returns 0, the helper will continue to the next loop. If return value is 1, the helper will skip the rest of the loops and return. Other return values are not used now, and will be rejected by the verifier.
Returns
The number of loops performed, -EINVAL for invalid flags, -E2BIG if nr_loops exceeds the maximum number of loops.
static long (* const bpf_loop)(__u32 nr_loops, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 181;
Usage
Docs could be improved
This part of the docs is incomplete, contributions are very welcome
Program types
This helper call can be used in the following program types:
- BPF_PROG_TYPE_CGROUP_DEVICE
- BPF_PROG_TYPE_CGROUP_SKB
- BPF_PROG_TYPE_CGROUP_SOCK
- BPF_PROG_TYPE_CGROUP_SOCKOPT
- BPF_PROG_TYPE_CGROUP_SOCK_ADDR
- BPF_PROG_TYPE_CGROUP_SYSCTL
- BPF_PROG_TYPE_FLOW_DISSECTOR
- BPF_PROG_TYPE_KPROBE
- BPF_PROG_TYPE_LSM
- BPF_PROG_TYPE_LWT_IN
- BPF_PROG_TYPE_LWT_OUT
- BPF_PROG_TYPE_LWT_SEG6LOCAL
- BPF_PROG_TYPE_LWT_XMIT
- BPF_PROG_TYPE_PERF_EVENT
- BPF_PROG_TYPE_RAW_TRACEPOINT
- BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE
- BPF_PROG_TYPE_SCHED_ACT
- BPF_PROG_TYPE_SCHED_CLS
- BPF_PROG_TYPE_SK_LOOKUP
- BPF_PROG_TYPE_SK_MSG
- BPF_PROG_TYPE_SK_REUSEPORT
- BPF_PROG_TYPE_SK_SKB
- BPF_PROG_TYPE_SOCKET_FILTER
- BPF_PROG_TYPE_SOCK_OPS
- BPF_PROG_TYPE_SYSCALL
- BPF_PROG_TYPE_TRACEPOINT
- BPF_PROG_TYPE_TRACING
- BPF_PROG_TYPE_XDP
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome