1 // SPDX-License-Identifier: GPL-2.0-only 2 3 /* 4 * Copyright 2020 Google LLC. 5 */ 6 7 #include <errno.h> 8 #include <linux/bpf.h> 9 #include <linux/if_ether.h> 10 #include <linux/ip.h> 11 #include <bpf/bpf_helpers.h> 12 13 struct { 14 __uint(type, BPF_MAP_TYPE_ARRAY); 15 __uint(max_entries, 1); 16 __type(key, __u32); 17 __type(value, __u32); 18 } test_result SEC(".maps"); 19 20 SEC("cgroup_skb/egress") 21 int load_bytes_relative(struct __sk_buff *skb) 22 { 23 struct ethhdr eth; 24 struct iphdr iph; 25 26 __u32 map_key = 0; 27 __u32 test_passed = 0; 28 29 /* MAC header is not set by the time cgroup_skb/egress triggers */ 30 if (bpf_skb_load_bytes_relative(skb, 0, ð, sizeof(eth), 31 BPF_HDR_START_MAC) != -EFAULT) 32 goto fail; 33 34 if (bpf_skb_load_bytes_relative(skb, 0, &iph, sizeof(iph), 35 BPF_HDR_START_NET)) 36 goto fail; 37 38 if (bpf_skb_load_bytes_relative(skb, 0xffff, &iph, sizeof(iph), 39 BPF_HDR_START_NET) != -EFAULT) 40 goto fail; 41 42 test_passed = 1; 43 44 fail: 45 bpf_map_update_elem(&test_result, &map_key, &test_passed, BPF_ANY); 46 47 return 1; 48 } 49