Contributors: 1
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Cheng-Yang Chou |
143 |
100.00% |
1 |
100.00% |
| Total |
143 |
|
1 |
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Verify that context-sensitive SCX kfuncs (even "unlocked" ones) are
* restricted to only SCX struct_ops programs. Non-SCX struct_ops programs,
* such as TCP congestion control programs, should be rejected by the BPF
* verifier when attempting to call these kfuncs.
*
* Copyright (C) 2026 Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
* Copyright (C) 2026 Cheng-Yang Chou <yphbchou0911@gmail.com>
*/
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
/* SCX kfunc from scx_kfunc_ids_any set */
void scx_bpf_kick_cpu(s32 cpu, u64 flags) __ksym;
SEC("struct_ops/ssthresh")
__u32 BPF_PROG(tcp_ca_ssthresh, struct sock *sk)
{
/*
* This call should be rejected by the verifier because this is a
* TCP congestion control program (non-SCX struct_ops).
*/
scx_bpf_kick_cpu(0, 0);
return 2;
}
SEC("struct_ops/cong_avoid")
void BPF_PROG(tcp_ca_cong_avoid, struct sock *sk, __u32 ack, __u32 acked) {}
SEC("struct_ops/undo_cwnd")
__u32 BPF_PROG(tcp_ca_undo_cwnd, struct sock *sk) { return 2; }
SEC(".struct_ops")
struct tcp_congestion_ops tcp_non_scx_ca = {
.ssthresh = (void *)tcp_ca_ssthresh,
.cong_avoid = (void *)tcp_ca_cong_avoid,
.undo_cwnd = (void *)tcp_ca_undo_cwnd,
.name = "tcp_kfunc_deny",
};
char _license[] SEC("license") = "GPL";