1 /* 2 * Copyright (C) 2021 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <linux/if_ether.h> 18 #include <linux/in.h> 19 #include <linux/ip.h> 20 21 #include "bpf_helpers.h" 22 #include "bpf_net_helpers.h" 23 #include "bpf_tethering.h" 24 25 // Used only by TetheringPrivilegedTests, not by production code. 26 DEFINE_BPF_MAP_GRW(tether_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 16, 27 AID_NETWORK_STACK) 28 29 DEFINE_BPF_PROG_KVER("xdp/drop_ipv4_udp_ether", AID_ROOT, AID_NETWORK_STACK, 30 xdp_test, KVER(5, 9, 0)) 31 (struct xdp_md *ctx) { 32 void *data = (void *)(long)ctx->data; 33 void *data_end = (void *)(long)ctx->data_end; 34 35 struct ethhdr *eth = data; 36 int hsize = sizeof(*eth); 37 38 struct iphdr *ip = data + hsize; 39 hsize += sizeof(struct iphdr); 40 41 if (data + hsize > data_end) return XDP_PASS; 42 if (eth->h_proto != htons(ETH_P_IP)) return XDP_PASS; 43 if (ip->protocol == IPPROTO_UDP) return XDP_DROP; 44 return XDP_PASS; 45 } 46 47 LICENSE("Apache 2.0"); 48