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 #ifdef MAINLINE 22 // BTF is incompatible with bpfloaders < v0.10, hence for S (v0.2) we must 23 // ship a different file than for later versions, but we need bpfloader v0.25+ 24 // for obj@ver.o support 25 #define BPFLOADER_MIN_VER BPFLOADER_MAINLINE_T_VERSION 26 #else /* MAINLINE */ 27 // The resulting .o needs to load on the Android S bpfloader 28 #define BPFLOADER_MIN_VER BPFLOADER_S_VERSION 29 #define BPFLOADER_MAX_VER BPFLOADER_T_VERSION 30 #endif /* MAINLINE */ 31 32 // Warning: values other than AID_ROOT don't work for map uid on BpfLoader < v0.21 33 #define TETHERING_UID AID_ROOT 34 35 #define TETHERING_GID AID_NETWORK_STACK 36 37 // This is non production code, only used for testing 38 // Needed because the bitmap array definition is non-kosher for pre-T OS devices. 39 #define THIS_BPF_PROGRAM_IS_FOR_TEST_PURPOSES_ONLY 40 41 #include "bpf_helpers.h" 42 #include "bpf_net_helpers.h" 43 #include "offload.h" 44 45 // Used only by TetheringPrivilegedTests, not by production code. 46 DEFINE_BPF_MAP_GRW(tether_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 16, 47 TETHERING_GID) 48 DEFINE_BPF_MAP_GRW(tether2_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 16, 49 TETHERING_GID) 50 DEFINE_BPF_MAP_GRW(tether3_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 16, 51 TETHERING_GID) 52 // Used only by BpfBitmapTest, not by production code. 53 DEFINE_BPF_MAP_GRW(bitmap, ARRAY, int, uint64_t, 2, TETHERING_GID) 54 55 DEFINE_BPF_PROG_KVER("xdp/drop_ipv4_udp_ether", TETHERING_UID, TETHERING_GID, 56 xdp_test, KVER_5_9) 57 (struct xdp_md *ctx) { 58 void *data = (void *)(long)ctx->data; 59 void *data_end = (void *)(long)ctx->data_end; 60 61 struct ethhdr *eth = data; 62 int hsize = sizeof(*eth); 63 64 struct iphdr *ip = data + hsize; 65 hsize += sizeof(struct iphdr); 66 67 if (data + hsize > data_end) return XDP_PASS; 68 if (eth->h_proto != htons(ETH_P_IP)) return XDP_PASS; 69 if (ip->protocol == IPPROTO_UDP) return XDP_DROP; 70 return XDP_PASS; 71 } 72 73 LICENSE("Apache 2.0"); 74 DISABLE_BTF_ON_USER_BUILDS(); 75