bpf/progs/recursion.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2021 Facebook */
0003
0004 #include "vmlinux.h"
0005 #include <bpf/bpf_helpers.h>
0006 #include <bpf/bpf_tracing.h>
0007
0008 char _license[] SEC("license") = "GPL";
0009
0010 struct {
0011     __uint(type, BPF_MAP_TYPE_HASH);
0012     __uint(max_entries, 1);
0013     __type(key, int);
0014     __type(value, long);
0015 } hash1 SEC(".maps");
0016
0017 struct {
0018     __uint(type, BPF_MAP_TYPE_HASH);
0019     __uint(max_entries, 1);
0020     __type(key, int);
0021     __type(value, long);
0022 } hash2 SEC(".maps");
0023
0024 int pass1 = 0;
0025 int pass2 = 0;
0026
0027 SEC("fentry/htab_map_delete_elem")
0028 int BPF_PROG(on_delete, struct bpf_map *map)
0029 {
0030     int key = 0;
0031
0032     if (map == (void *)&hash1) {
0033         pass1++;
0034         return 0;
0035     }
0036     if (map == (void *)&hash2) {
0037         pass2++;
0038         bpf_map_delete_elem(&hash2, &key);
0039         return 0;
0040     }
0041
0042     return 0;
0043 }