1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #include <sys/socket.h> 4 #include <linux/bpf.h> 5 #include <bpf/bpf_helpers.h> 6 7 int invocations = 0, in_use = 0; 8 9 struct { 10 __uint(type, BPF_MAP_TYPE_SK_STORAGE); 11 __uint(map_flags, BPF_F_NO_PREALLOC); 12 __type(key, int); 13 __type(value, int); 14 } sk_map SEC(".maps"); 15 16 SEC("cgroup/sock_create") 17 int sock(struct bpf_sock *ctx) 18 { 19 int *sk_storage; 20 21 if (ctx->type != SOCK_DGRAM) 22 return 1; 23 24 sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 25 BPF_SK_STORAGE_GET_F_CREATE); 26 if (!sk_storage) 27 return 0; 28 *sk_storage = 0xdeadbeef; 29 30 __sync_fetch_and_add(&invocations, 1); 31 32 if (in_use > 0) { 33 /* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called 34 * when we return an error from the BPF 35 * program! 36 */ 37 return 0; 38 } 39 40 __sync_fetch_and_add(&in_use, 1); 41 return 1; 42 } 43 44 SEC("cgroup/sock_release") 45 int sock_release(struct bpf_sock *ctx) 46 { 47 int *sk_storage; 48 49 if (ctx->type != SOCK_DGRAM) 50 return 1; 51 52 sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 0); 53 if (!sk_storage || *sk_storage != 0xdeadbeef) 54 return 0; 55 56 __sync_fetch_and_add(&invocations, 1); 57 __sync_fetch_and_add(&in_use, -1); 58 return 1; 59 } 60