1 #include <linux/bpf.h> 2 #include "bpf_helpers.h" 3 #include "bpf_endian.h" 4 5 int _version SEC("version") = 1; 6 7 struct bpf_map_def SEC("maps") sock_map_rx = { 8 .type = BPF_MAP_TYPE_SOCKMAP, 9 .key_size = sizeof(int), 10 .value_size = sizeof(int), 11 .max_entries = 20, 12 }; 13 14 struct bpf_map_def SEC("maps") sock_map_tx = { 15 .type = BPF_MAP_TYPE_SOCKMAP, 16 .key_size = sizeof(int), 17 .value_size = sizeof(int), 18 .max_entries = 20, 19 }; 20 21 struct bpf_map_def SEC("maps") sock_map_msg = { 22 .type = BPF_MAP_TYPE_SOCKMAP, 23 .key_size = sizeof(int), 24 .value_size = sizeof(int), 25 .max_entries = 20, 26 }; 27 28 struct bpf_map_def SEC("maps") sock_map_break = { 29 .type = BPF_MAP_TYPE_ARRAY, 30 .key_size = sizeof(int), 31 .value_size = sizeof(int), 32 .max_entries = 20, 33 }; 34 35 SEC("sk_skb2") 36 int bpf_prog2(struct __sk_buff *skb) 37 { 38 void *data_end = (void *)(long) skb->data_end; 39 void *data = (void *)(long) skb->data; 40 __u32 lport = skb->local_port; 41 __u32 rport = skb->remote_port; 42 __u8 *d = data; 43 __u8 sk, map; 44 45 if (data + 8 > data_end) 46 return SK_DROP; 47 48 map = d[0]; 49 sk = d[1]; 50 51 d[0] = 0xd; 52 d[1] = 0xe; 53 d[2] = 0xa; 54 d[3] = 0xd; 55 d[4] = 0xb; 56 d[5] = 0xe; 57 d[6] = 0xe; 58 d[7] = 0xf; 59 60 if (!map) 61 return bpf_sk_redirect_map(skb, &sock_map_rx, sk, 0); 62 return bpf_sk_redirect_map(skb, &sock_map_tx, sk, 0); 63 } 64 65 char _license[] SEC("license") = "GPL"; 66