LineageOS/android_packages_modules_Connectivity
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Merge changes I3fcd7eb8,I4bf2c762 am: d46b3d8ef8 am: 0681ae3e9a am: 79079db8af

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Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1575050

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I3b105b58eb6d19f6d6b2f2120530ecd16df6a259
This commit is contained in:
Maciej Żenczykowski
2021-02-09 05:02:26 +00:00
committed by Automerger Merge Worker
parent acf3792680 79079db8af
commit 3e6764900e
4 changed files with 97 additions and 13 deletions
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5
Tethering/Android.bp
View File

@@ -62,7 +62,10 @@ cc_library {
"com.android.tethering",
],
min_sdk_version: "30",
header_libs: ["bpf_syscall_wrappers"],
header_libs: [
"bpf_syscall_wrappers",
"bpf_tethering_headers",
],
srcs: [
"jni/*.cpp",
],

20
Tethering/bpf_progs/Android.bp
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@@ -14,6 +14,26 @@
// limitations under the License.
//
//
// struct definitions shared with JNI
//
cc_library_headers {
name: "bpf_tethering_headers",
vendor_available: false,
host_supported: false,
export_include_dirs: ["."],
cflags: [
"-Wall",
"-Werror",
],
sdk_version: "30",
min_sdk_version: "30",
apex_available: ["com.android.tethering"],
visibility: [
"//packages/modules/Connectivity/Tethering",
],
}
//
// bpf kernel programs
//

49
Tethering/bpf_progs/bpf_tethering.h Normal file
View File

@@ -0,0 +1,49 @@
/*
* Copyright (C) 2021 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.
*/
#pragma once
// Common definitions for BPF code in the tethering mainline module.
// These definitions are available to:
// - The BPF programs in Tethering/bpf_progs/
// - JNI code that depends on the bpf_tethering_headers library.
#define BPF_TETHER_ERRORS \
ERR(INVALID_IP_VERSION) \
ERR(LOW_TTL) \
ERR(INVALID_TCP_HEADER) \
ERR(TCP_CONTROL_PACKET) \
ERR(NON_GLOBAL_SRC) \
ERR(NON_GLOBAL_DST) \
ERR(LOCAL_SRC_DST) \
ERR(NO_STATS_ENTRY) \
ERR(NO_LIMIT_ENTRY) \
ERR(BELOW_IPV6_MTU) \
ERR(LIMIT_REACHED) \
ERR(CHANGE_HEAD_FAILED) \
ERR(_MAX)
#define ERR(x) BPF_TETHER_ERR_ ##x,
enum {
BPF_TETHER_ERRORS
};
#undef ERR
#define ERR(x) #x,
static const char *bpf_tether_errors[] = {
BPF_TETHER_ERRORS
};
#undef ERR

36
Tethering/bpf_progs/offload.c
View File

@@ -26,6 +26,7 @@
#include "bpf_helpers.h"
#include "bpf_net_helpers.h"
#include "bpf_tethering.h"
#include "netdbpf/bpf_shared.h"
// From kernel:include/net/ip.h
@@ -49,6 +50,16 @@ DEFINE_BPF_MAP_GRW(tether_downstream64_map, HASH, TetherDownstream64Key, TetherD
DEFINE_BPF_MAP_GRW(tether_upstream6_map, HASH, TetherUpstream6Key, Tether6Value, 64,
AID_NETWORK_STACK)
DEFINE_BPF_MAP_GRW(tether_error_map, ARRAY, __u32, __u32, BPF_TETHER_ERR__MAX,
AID_NETWORK_STACK)
#define ERROR_EXIT(error) do { \
__u32 errcode = BPF_TETHER_ERR_ ## error; \
__u32 *errcount = bpf_tether_error_map_lookup_elem(&errcode); \
if (errcount) __sync_fetch_and_add(errcount, 1); \
return TC_ACT_OK; \
} while(0)
static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool is_ethernet,
const bool downstream) {
const int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
@@ -70,11 +81,11 @@ static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool
if (is_ethernet && (eth->h_proto != htons(ETH_P_IPV6))) return TC_ACT_OK;
// IP version must be 6
if (ip6->version != 6) return TC_ACT_OK;
if (ip6->version != 6) ERROR_EXIT(INVALID_IP_VERSION);
// Cannot decrement during forward if already zero or would be zero,
// Let the kernel's stack handle these cases and generate appropriate ICMP errors.
if (ip6->hop_limit <= 1) return TC_ACT_OK;
if (ip6->hop_limit <= 1) ERROR_EXIT(LOW_TTL);
// If hardware offload is running and programming flows based on conntrack entries,
// try not to interfere with it.
@@ -82,27 +93,28 @@ static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool
struct tcphdr* tcph = (void*)(ip6 + 1);
// Make sure we can get at the tcp header
if (data + l2_header_size + sizeof(*ip6) + sizeof(*tcph) > data_end) return TC_ACT_OK;
if (data + l2_header_size + sizeof(*ip6) + sizeof(*tcph) > data_end)
ERROR_EXIT(INVALID_TCP_HEADER);
// Do not offload TCP packets with any one of the SYN/FIN/RST flags
if (tcph->syn || tcph->fin || tcph->rst) return TC_ACT_OK;
if (tcph->syn || tcph->fin || tcph->rst) ERROR_EXIT(TCP_CONTROL_PACKET);
}
// Protect against forwarding packets sourced from ::1 or fe80::/64 or other weirdness.
__be32 src32 = ip6->saddr.s6_addr32[0];
if (src32 != htonl(0x0064ff9b) && // 64:ff9b:/32 incl. XLAT464 WKP
(src32 & htonl(0xe0000000)) != htonl(0x20000000)) // 2000::/3 Global Unicast
return TC_ACT_OK;
ERROR_EXIT(NON_GLOBAL_SRC);
// Protect against forwarding packets destined to ::1 or fe80::/64 or other weirdness.
__be32 dst32 = ip6->daddr.s6_addr32[0];
if (dst32 != htonl(0x0064ff9b) && // 64:ff9b:/32 incl. XLAT464 WKP
(dst32 & htonl(0xe0000000)) != htonl(0x20000000)) // 2000::/3 Global Unicast
return TC_ACT_OK;
ERROR_EXIT(NON_GLOBAL_DST);
// In the upstream direction do not forward traffic within the same /64 subnet.
if (!downstream && (src32 == dst32) && (ip6->saddr.s6_addr32[1] == ip6->daddr.s6_addr32[1]))
return TC_ACT_OK;
ERROR_EXIT(LOCAL_SRC_DST);
TetherDownstream6Key kd = {
.iif = skb->ifindex,
@@ -124,15 +136,15 @@ static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool
TetherStatsValue* stat_v = bpf_tether_stats_map_lookup_elem(&stat_and_limit_k);
// If we don't have anywhere to put stats, then abort...
if (!stat_v) return TC_ACT_OK;
if (!stat_v) ERROR_EXIT(NO_STATS_ENTRY);
uint64_t* limit_v = bpf_tether_limit_map_lookup_elem(&stat_and_limit_k);
// If we don't have a limit, then abort...
if (!limit_v) return TC_ACT_OK;
if (!limit_v) ERROR_EXIT(NO_LIMIT_ENTRY);
// Required IPv6 minimum mtu is 1280, below that not clear what we should do, abort...
if (v->pmtu < IPV6_MIN_MTU) return TC_ACT_OK;
if (v->pmtu < IPV6_MIN_MTU) ERROR_EXIT(BELOW_IPV6_MTU);
// Approximate handling of TCP/IPv6 overhead for incoming LRO/GRO packets: default
// outbound path mtu of 1500 is not necessarily correct, but worst case we simply
@@ -157,7 +169,7 @@ static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool
// a packet we let the core stack deal with things.
// (The core stack needs to handle limits correctly anyway,
// since we don't offload all traffic in both directions)
if (stat_v->rxBytes + stat_v->txBytes + bytes > *limit_v) return TC_ACT_OK;
if (stat_v->rxBytes + stat_v->txBytes + bytes > *limit_v) ERROR_EXIT(LIMIT_REACHED);
if (!is_ethernet) {
// Try to inject an ethernet header, and simply return if we fail.
@@ -165,7 +177,7 @@ static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool
// because this is easier and the kernel will strip extraneous ethernet header.
if (bpf_skb_change_head(skb, sizeof(struct ethhdr), /*flags*/ 0)) {
__sync_fetch_and_add(downstream ? &stat_v->rxErrors : &stat_v->txErrors, 1);
return TC_ACT_OK;
ERROR_EXIT(CHANGE_HEAD_FAILED);
}
// bpf_skb_change_head() invalidates all pointers - reload them