| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* |
| * This h file together with netd.c is used for compiling the eBPF kernel |
| * program. |
| */ |
| |
| #include <bpf_helpers.h> |
| #include <linux/bpf.h> |
| #include <linux/if.h> |
| #include <linux/if_ether.h> |
| #include <linux/in.h> |
| #include <linux/in6.h> |
| #include <linux/ip.h> |
| #include <linux/ipv6.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include "netdbpf/bpf_shared.h" |
| |
| struct uid_tag { |
| uint32_t uid; |
| uint32_t tag; |
| }; |
| |
| struct stats_key { |
| uint32_t uid; |
| uint32_t tag; |
| uint32_t counterSet; |
| uint32_t ifaceIndex; |
| }; |
| |
| struct stats_value { |
| uint64_t rxPackets; |
| uint64_t rxBytes; |
| uint64_t txPackets; |
| uint64_t txBytes; |
| }; |
| |
| struct IfaceValue { |
| char name[IFNAMSIZ]; |
| }; |
| |
| // This is defined for cgroup bpf filter only. |
| #define BPF_PASS 1 |
| #define BPF_DROP 0 |
| |
| // This is used for xt_bpf program only. |
| #define BPF_NOMATCH 0 |
| #define BPF_MATCH 1 |
| |
| #define BPF_EGRESS 0 |
| #define BPF_INGRESS 1 |
| |
| #define IP_PROTO_OFF offsetof(struct iphdr, protocol) |
| #define IPV6_PROTO_OFF offsetof(struct ipv6hdr, nexthdr) |
| #define IPPROTO_IHL_OFF 0 |
| #define TCP_FLAG_OFF 13 |
| #define RST_OFFSET 2 |
| |
| struct bpf_map_def SEC("maps") cookie_tag_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint64_t), |
| .value_size = sizeof(struct uid_tag), |
| .max_entries = COOKIE_UID_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") uid_counterset_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(uint8_t), |
| .max_entries = UID_COUNTERSET_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") app_uid_stats_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(struct stats_value), |
| .max_entries = APP_STATS_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") stats_map_A = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(struct stats_key), |
| .value_size = sizeof(struct stats_value), |
| .max_entries = STATS_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") stats_map_B = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(struct stats_key), |
| .value_size = sizeof(struct stats_value), |
| .max_entries = STATS_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") iface_stats_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(struct stats_value), |
| .max_entries = IFACE_STATS_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") configuration_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(uint8_t), |
| .max_entries = CONFIGURATION_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") uid_owner_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(uint8_t), |
| .max_entries = UID_OWNER_MAP_SIZE, |
| }; |
| |
| struct bpf_map_def SEC("maps") iface_index_name_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(uint32_t), |
| .value_size = sizeof(struct IfaceValue), |
| .max_entries = IFACE_INDEX_NAME_MAP_SIZE, |
| }; |
| |
| static __always_inline int is_system_uid(uint32_t uid) { |
| return (uid <= MAX_SYSTEM_UID) && (uid >= MIN_SYSTEM_UID); |
| } |
| |
| static __always_inline inline void bpf_update_stats(struct __sk_buff* skb, struct bpf_map_def* map, |
| int direction, void* key) { |
| struct stats_value* value; |
| value = bpf_map_lookup_elem(map, key); |
| if (!value) { |
| struct stats_value newValue = {}; |
| bpf_map_update_elem(map, key, &newValue, BPF_NOEXIST); |
| value = bpf_map_lookup_elem(map, key); |
| } |
| if (value) { |
| if (direction == BPF_EGRESS) { |
| __sync_fetch_and_add(&value->txPackets, 1); |
| __sync_fetch_and_add(&value->txBytes, skb->len); |
| } else if (direction == BPF_INGRESS) { |
| __sync_fetch_and_add(&value->rxPackets, 1); |
| __sync_fetch_and_add(&value->rxBytes, skb->len); |
| } |
| } |
| } |
| |
| static inline bool skip_owner_match(struct __sk_buff* skb) { |
| int offset = -1; |
| int ret = 0; |
| if (skb->protocol == ETH_P_IP) { |
| offset = IP_PROTO_OFF; |
| uint8_t proto, ihl; |
| uint16_t flag; |
| ret = bpf_skb_load_bytes(skb, offset, &proto, 1); |
| if (!ret) { |
| if (proto == IPPROTO_ESP) { |
| return true; |
| } else if (proto == IPPROTO_TCP) { |
| ret = bpf_skb_load_bytes(skb, IPPROTO_IHL_OFF, &ihl, 1); |
| ihl = ihl & 0x0F; |
| ret = bpf_skb_load_bytes(skb, ihl * 4 + TCP_FLAG_OFF, &flag, 1); |
| if (ret == 0 && (flag >> RST_OFFSET & 1)) { |
| return true; |
| } |
| } |
| } |
| } else if (skb->protocol == ETH_P_IPV6) { |
| offset = IPV6_PROTO_OFF; |
| uint8_t proto; |
| ret = bpf_skb_load_bytes(skb, offset, &proto, 1); |
| if (!ret) { |
| if (proto == IPPROTO_ESP) { |
| return true; |
| } else if (proto == IPPROTO_TCP) { |
| uint16_t flag; |
| ret = bpf_skb_load_bytes(skb, sizeof(struct ipv6hdr) + TCP_FLAG_OFF, &flag, 1); |
| if (ret == 0 && (flag >> RST_OFFSET & 1)) { |
| return true; |
| } |
| } |
| } |
| } |
| return false; |
| } |
| |
| static __always_inline BpfConfig getConfig(uint32_t configKey) { |
| uint32_t mapSettingKey = configKey; |
| BpfConfig* config = bpf_map_lookup_elem(&configuration_map, &mapSettingKey); |
| if (!config) { |
| // Couldn't read configuration entry. Assume everything is disabled. |
| return DEFAULT_CONFIG; |
| } |
| return *config; |
| } |
| |
| static inline int bpf_owner_match(struct __sk_buff* skb, uint32_t uid) { |
| if (skip_owner_match(skb)) return BPF_PASS; |
| |
| if ((uid <= MAX_SYSTEM_UID) && (uid >= MIN_SYSTEM_UID)) return BPF_PASS; |
| |
| BpfConfig enabledRules = getConfig(UID_RULES_CONFIGURATION_KEY); |
| if (!enabledRules) { |
| return BPF_PASS; |
| } |
| |
| uint8_t* uidEntry = bpf_map_lookup_elem(&uid_owner_map, &uid); |
| uint8_t uidRules = uidEntry ? *uidEntry : 0; |
| if ((enabledRules & DOZABLE_MATCH) && !(uidRules & DOZABLE_MATCH)) { |
| return BPF_DROP; |
| } |
| if ((enabledRules & STANDBY_MATCH) && (uidRules & STANDBY_MATCH)) { |
| return BPF_DROP; |
| } |
| if ((enabledRules & POWERSAVE_MATCH) && !(uidRules & POWERSAVE_MATCH)) { |
| return BPF_DROP; |
| } |
| return BPF_PASS; |
| } |
| |
| static __always_inline inline void update_stats_with_config(struct __sk_buff* skb, int direction, |
| void* key, uint8_t selectedMap) { |
| if (selectedMap == SELECT_MAP_A) { |
| bpf_update_stats(skb, &stats_map_A, direction, key); |
| } else if (selectedMap == SELECT_MAP_B) { |
| bpf_update_stats(skb, &stats_map_B, direction, key); |
| } |
| } |
| |
| static __always_inline inline int bpf_traffic_account(struct __sk_buff* skb, int direction) { |
| uint32_t sock_uid = bpf_get_socket_uid(skb); |
| int match = bpf_owner_match(skb, sock_uid); |
| if ((direction == BPF_EGRESS) && (match == BPF_DROP)) { |
| // If an outbound packet is going to be dropped, we do not count that |
| // traffic. |
| return match; |
| } |
| |
| uint64_t cookie = bpf_get_socket_cookie(skb); |
| struct uid_tag* utag = bpf_map_lookup_elem(&cookie_tag_map, &cookie); |
| uint32_t uid, tag; |
| if (utag) { |
| uid = utag->uid; |
| tag = utag->tag; |
| } else { |
| uid = sock_uid; |
| tag = 0; |
| } |
| |
| struct stats_key key = {.uid = uid, .tag = tag, .counterSet = 0, .ifaceIndex = skb->ifindex}; |
| |
| uint8_t* counterSet = bpf_map_lookup_elem(&uid_counterset_map, &uid); |
| if (counterSet) key.counterSet = (uint32_t)*counterSet; |
| |
| uint32_t mapSettingKey = CURRENT_STATS_MAP_CONFIGURATION_KEY; |
| uint8_t* selectedMap = bpf_map_lookup_elem(&configuration_map, &mapSettingKey); |
| if (!selectedMap) { |
| return match; |
| } |
| |
| if (tag) { |
| update_stats_with_config(skb, direction, &key, *selectedMap); |
| } |
| |
| key.tag = 0; |
| update_stats_with_config(skb, direction, &key, *selectedMap); |
| bpf_update_stats(skb, &app_uid_stats_map, direction, &uid); |
| return match; |
| } |