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Merge changes from topic "bpf_header_files1" into main

Browse source 
* changes:
  Remove unused bpfRingbufProg.o
  Add copy of bpf header files for platform use
This commit is contained in:
Treehugger Robot 2025-06-13 04:32:44 -07:00 • committed by Android (Google) Code Review
commit 821600428c
3 changed files with 815 additions and 5 deletions
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include/bpf/bpf_helpers.h Normal file
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/* Common BPF helpers to be used by all BPF programs loaded by Android */
#include <linux/bpf.h>
#include <stdbool.h>
#include <stdint.h>
#include "bpf_map_def.h"
/******************************************************************************
* WARNING: CHANGES TO THIS FILE OUTSIDE OF AOSP/MAIN ARE LIKELY TO BREAK *
* DEVICE COMPATIBILITY WITH MAINLINE MODULES SHIPPING EBPF CODE. *
* *
* THIS WILL LIKELY RESULT IN BRICKED DEVICES AT SOME ARBITRARY FUTURE TIME *
* *
* THAT GOES ESPECIALLY FOR THE 'SECTION' 'LICENSE' AND 'CRITICAL' MACROS *
* *
* We strongly suggest that if you need changes to bpfloader functionality *
* you get your changes reviewed and accepted into aosp/master. *
* *
******************************************************************************/
// The actual versions of the bpfloader that shipped in various Android releases
// Android P/Q/R: BpfLoader was initially part of netd,
// this was later split out into a standalone binary, but was unversioned.
// Android S / 12 (api level 31) - added 'tethering' mainline eBPF support
#define BPFLOADER_S_VERSION 2u
// Android T / 13 (api level 33) - support for shared/selinux_context/pindir
#define BPFLOADER_T_VERSION 19u
// BpfLoader v0.25+ support obj@ver.o files
#define BPFLOADER_OBJ_AT_VER_VERSION 25u
// Bpfloader v0.33+ supports {map,prog}.ignore_on_{eng,user,userdebug}
#define BPFLOADER_IGNORED_ON_VERSION 33u
// Android U / 14 (api level 34) - various new program types added
#define BPFLOADER_U_VERSION 38u
// Android U QPR2 / 14 (api level 34) - platform only
// (note: the platform bpfloader in V isn't really versioned at all,
// as there is no need as it can only load objects compiled at the
// same time as itself and the rest of the platform)
#define BPFLOADER_U_QPR2_VERSION 41u
#define BPFLOADER_PLATFORM_VERSION BPFLOADER_U_QPR2_VERSION
// Android Mainline BpfLoader when running on Android S (sdk=31)
// Note: this value (and the following +1u's) are hardcoded in NetBpfLoad.cpp
#define BPFLOADER_MAINLINE_S_VERSION 42u
// Android Mainline BpfLoader when running on Android T (sdk=33)
#define BPFLOADER_MAINLINE_T_VERSION (BPFLOADER_MAINLINE_S_VERSION + 1u)
// Android Mainline BpfLoader when running on Android U (sdk=34)
#define BPFLOADER_MAINLINE_U_VERSION (BPFLOADER_MAINLINE_T_VERSION + 1u)
// Android Mainline BpfLoader when running on Android U QPR3
#define BPFLOADER_MAINLINE_U_QPR3_VERSION (BPFLOADER_MAINLINE_U_VERSION + 1u)
// Android Mainline BpfLoader when running on Android V (sdk=35)
#define BPFLOADER_MAINLINE_V_VERSION (BPFLOADER_MAINLINE_U_QPR3_VERSION + 1u)
// Android Mainline BpfLoader when running on Android 25Q2 (sdk=36 aka 36.0)
#define BPFLOADER_MAINLINE_25Q2_VERSION (BPFLOADER_MAINLINE_V_VERSION + 1u)
// Android Mainline BpfLoader when running on Android 25Q3 (sdk 36.0+)
#define BPFLOADER_MAINLINE_25Q3_VERSION (BPFLOADER_MAINLINE_25Q2_VERSION + 1u)
// Android Mainline BpfLoader when running on Android 25Q4 (sdk 36.1)
#define BPFLOADER_MAINLINE_25Q4_VERSION (BPFLOADER_MAINLINE_25Q3_VERSION + 1u)
// Android Mainline BpfLoader when running on Android 26Q1 (sdk 36.1+)
#define BPFLOADER_MAINLINE_26Q1_VERSION (BPFLOADER_MAINLINE_25Q4_VERSION + 1u)
// Android Mainline BpfLoader when running on Android 26Q2 (sdk 37.0)
#define BPFLOADER_MAINLINE_26Q2_VERSION (BPFLOADER_MAINLINE_26Q1_VERSION + 1u)
/* For mainline module use, you can #define BPFLOADER_{MIN/MAX}_VER
* before #include "bpf_helpers.h" to change which bpfloaders will
* process the resulting .o file.
*
* While this will work outside of mainline too, there just is no point to
* using it when the .o and the bpfloader ship in sync with each other.
* In which case it's just best to use the default.
*/
#ifndef BPFLOADER_MIN_VER
#define BPFLOADER_MIN_VER BPFLOADER_PLATFORM_VERSION // inclusive, ie. >=
#endif
#ifndef BPFLOADER_MAX_VER
#define BPFLOADER_MAX_VER 0x10000u // exclusive, ie. < v1.0
#endif
/* place things in different elf sections */
#define SECTION(NAME) __attribute__((section(NAME), used))
/* Must be present in every program, example usage:
* LICENSE("GPL"); or LICENSE("Apache 2.0");
*
* We also take this opportunity to embed a bunch of other useful values in
* the resulting .o (This is to enable some limited forward compatibility
* with mainline module shipped ebpf programs)
*
* The bpfloader_{min/max}_ver defines the [min, max) range of bpfloader
* versions that should load this .o file (bpfloaders outside of this range
* will simply ignore/skip this *entire* .o)
* The [inclusive,exclusive) matches what we do for kernel ver dependencies.
*
* The size_of_bpf_{map,prog}_def allow the bpfloader to load programs where
* these structures have been extended with additional fields (they will of
* course simply be ignored then).
*
* If missing, bpfloader_{min/max}_ver default to 0/0x10000 ie. [v0.0, v1.0),
* while size_of_bpf_{map/prog}_def default to 32/20 which are the v0.0 sizes.
*
* This macro also disables loading BTF map debug information, as versions
* of the platform bpfloader that support BTF require fork-exec of btfloader
* which causes a regression in boot time.
*/
#define LICENSE(NAME) \
unsigned int _bpfloader_min_ver SECTION("bpfloader_min_ver") = BPFLOADER_MIN_VER; \
unsigned int _bpfloader_max_ver SECTION("bpfloader_max_ver") = BPFLOADER_MAX_VER; \
size_t _size_of_bpf_map_def SECTION("size_of_bpf_map_def") = sizeof(struct bpf_map_def); \
size_t _size_of_bpf_prog_def SECTION("size_of_bpf_prog_def") = sizeof(struct bpf_prog_def); \
unsigned _btf_min_bpfloader_ver SECTION("btf_min_bpfloader_ver") = BPFLOADER_MAINLINE_S_VERSION; \
unsigned _btf_user_min_bpfloader_ver SECTION("btf_user_min_bpfloader_ver") = 0xFFFFFFFFu; \
char _license[] SECTION("license") = (NAME)
/* flag the resulting bpf .o file as critical to system functionality,
* loading all kernel version appropriate programs in it must succeed
* for bpfloader success
*/
#define CRITICAL(REASON) char _critical[] SECTION("critical") = (REASON)
// Helpers for writing kernel version specific bpf programs
struct kver_uint { unsigned int kver; };
#define KVER_(v) ((struct kver_uint){ .kver = (v) })
#define KVER(a, b, c) KVER_(((a) << 24) + ((b) << 16) + (c))
#define KVER_NONE KVER_(0)
#define KVER_4_9 KVER(4, 9, 0)
#define KVER_4_14 KVER(4, 14, 0)
#define KVER_4_19 KVER(4, 19, 0)
#define KVER_5_4 KVER(5, 4, 0)
#define KVER_5_10 KVER(5, 10, 0)
#define KVER_5_15 KVER(5, 15, 0)
#define KVER_6_1 KVER(6, 1, 0)
#define KVER_6_6 KVER(6, 6, 0)
#define KVER_6_12 KVER(6, 12, 0)
#define KVER_INF KVER_(0xFFFFFFFFu)
#define KVER_IS_AT_LEAST(kver, a, b, c) ((kver).kver >= KVER(a, b, c).kver)
// Helpers for writing sdk level specific bpf programs
//
// Note: we choose to follow 'ro.build.version.sdk_full'
// (or just 'sdk' if 'sdk_full' is not available) values,
// multiplied by 100, with 1 added per QPR.
// This will (eventually) match our bpfloader versioning scheme.
//
// This is just for ease of use, really these are only
// ever compared to each other, so they only need to be
// monotonically increasing.
//
// For now this easily suffices for our use case.
//
// Note: 24Q1 is the first trunk stable release,
// and thus where quarters start possibly mattering.
//
// We leave most of these as commented out documentation,
// as it's probably a bad idea to actually use them.
struct sdk_level_uint { unsigned int sdk_level; };
#define SDK_LEVEL_(v) ((struct sdk_level_uint){ .sdk_level = (v) })
// SDK_LEVEL_NONE SDK_LEVEL_(0) // mainline implies S+
#define SDK_LEVEL_S SDK_LEVEL_(3100) // Android 12 [31]
// SDK_LEVEL_Sv2 SDK_LEVEL_(3200) // Android 12L [32]
#define SDK_LEVEL_T SDK_LEVEL_(3300) // Android 13 [33]
#define SDK_LEVEL_U SDK_LEVEL_(3400) // Android 14/U [34]
// SDK_LEVEL_U_QPR1 SDK_LEVEL_(3401) // Android 14/U QPR1
// SDK_LEVEL_24Q1 SDK_LEVEL_(3402) // Android 14/U QPR2
// SDK_LEVEL_24Q2 SDK_LEVEL_(3403) // Android 14/U QPR3
#define SDK_LEVEL_24Q3 SDK_LEVEL_(3500) // Android 15/V [35]
// SDK_LEVEL_24Q4 SDK_LEVEL_(3501) // Android 15/V QPR1
// SDK_LEVEL_25Q1 SDK_LEVEL_(3502) // Android 15/V QPR2
#define SDK_LEVEL_25Q2 SDK_LEVEL_(3600) // Android 16 (B) [36.0]
// SDK_LEVEL_25Q3 SDK_LEVEL_(3601) // Android 16 QPR
#define SDK_LEVEL_25Q4 SDK_LEVEL_(3610) // Android 16.1 [36.1]
// SDK_LEVEL_26Q1 SDK_LEVEL_(3611) // Android 16.1 QPR
#define SDK_LEVEL_26Q2 SDK_LEVEL_(3700) // Android 17 (C) [37.0]
// SDK_LEVEL_26Q3 SDK_LEVEL_(3701) // Android 17 QPR
#define SDK_LEVEL_26Q4 SDK_LEVEL_(3710) // Android 17.1 [37.1]
// SDK_LEVEL_27Q1 SDK_LEVEL_(3711) // Android 17.1 QPR
#define SDK_LEVEL_27Q2 SDK_LEVEL_(3800) // Android 18 [38.0]
#define SDK_LEVEL_IS_AT_LEAST(lvl, v) ((lvl).sdk_level >= (SDK_LEVEL_##v).sdk_level)
/*
* BPFFS (ie. /sys/fs/bpf) labelling is as follows:
* subdirectory selinux context mainline usecase / usable by
* / fs_bpf no [*] core operating system (ie. platform)
* /loader fs_bpf_loader no, U+ (as yet unused)
* /net_private fs_bpf_net_private yes, T+ network_stack
* /net_shared fs_bpf_net_shared yes, T+ network_stack & system_server
* /netd_readonly fs_bpf_netd_readonly yes, T+ network_stack & system_server & r/o to netd
* /netd_shared fs_bpf_netd_shared yes, T+ network_stack & system_server & netd [**]
* /tethering fs_bpf_tethering yes, S+ network_stack
* /vendor fs_bpf_vendor no, T+ vendor
*
* [*] initial support for bpf was added back in P,
* but things worked differently back then with no bpfloader,
* and instead netd doing stuff by hand,
* bpfloader with pinning into /sys/fs/bpf was (I believe) added in Q
* (and was definitely there in R).
*
* [**] additionally bpf programs are accessible to netutils_wrapper
* for use by iptables xt_bpf extensions.
*
* See cs/p:aosp-master%20-file:prebuilts/%20file:genfs_contexts%20"genfscon%20bpf"
*/
/*
* Helper functions called from eBPF programs written in C. These are
* implemented in the kernel sources.
*/
/* generic functions */
/*
* Type-unsafe bpf map functions - avoid if possible.
*
* Using these it is possible to pass in keys/values of the wrong type/size,
* or, for 'bpf_map_lookup_elem_unsafe' receive into a pointer to the wrong type.
* You will not get a compile time failure, and for certain types of errors you
* might not even get a failure from the kernel's ebpf verifier during program load,
* instead stuff might just not work right at runtime.
*
* Instead please use:
* DEFINE_BPF_MAP(foo_map, TYPE, KeyType, ValueType, num_entries)
* where TYPE can be something like HASH or ARRAY, and num_entries is an integer.
*
* This defines the map (hence this should not be used in a header file included
* from multiple locations) and provides type safe accessors:
* ValueType * bpf_foo_map_lookup_elem(const KeyType *)
* int bpf_foo_map_update_elem(const KeyType *, const ValueType *, flags)
* int bpf_foo_map_delete_elem(const KeyType *)
*
* This will make sure that if you change the type of a map you'll get compile
* errors at any spots you forget to update with the new type.
*
* Note: these all take pointers to const map because from the C/eBPF point of view
* the map struct is really just a readonly map definition of the in kernel object.
* Runtime modification of the map defining struct is meaningless, since
* the contents is only ever used during bpf program loading & map creation
* by the bpf loader, and not by the eBPF program itself.
*/
static void* (*bpf_map_lookup_elem_unsafe)(const struct bpf_map_def* map,
const void* key) = (void*)BPF_FUNC_map_lookup_elem;
static int (*bpf_map_update_elem_unsafe)(const struct bpf_map_def* map, const void* key,
const void* value, unsigned long long flags) = (void*)
BPF_FUNC_map_update_elem;
static int (*bpf_map_delete_elem_unsafe)(const struct bpf_map_def* map,
const void* key) = (void*)BPF_FUNC_map_delete_elem;
static int (*bpf_ringbuf_output_unsafe)(const struct bpf_map_def* ringbuf,
const void* data, __u64 size, __u64 flags) = (void*)
BPF_FUNC_ringbuf_output;
static void* (*bpf_ringbuf_reserve_unsafe)(const struct bpf_map_def* ringbuf,
__u64 size, __u64 flags) = (void*)
BPF_FUNC_ringbuf_reserve;
static void (*bpf_ringbuf_submit_unsafe)(const void* data, __u64 flags) = (void*)
BPF_FUNC_ringbuf_submit;
static void* (*bpf_sk_storage_get_unsafe) (const struct bpf_map_def* sk_storage, const void* sk,
const void* value, unsigned long long flags) = (void*)
BPF_FUNC_sk_storage_get;
static int (*bpf_sk_storage_delete_unsafe) (const struct bpf_map_def* sk_storage,
const void* sk) = (void*) BPF_FUNC_sk_storage_delete;
#define BPF_ANNOTATE_KV_PAIR(name, type_key, type_val) \
struct ____btf_map_##name { \
type_key key; \
type_val value; \
}; \
struct ____btf_map_##name \
__attribute__ ((section(".maps." #name), used)) \
____btf_map_##name = { }
#define ABSOLUTE(x) ((x) < 0 ? -(x) : (x))
#define DEFAULT_BPF_MAP_FLAGS(type, num_entries, mapflags) \
( (mapflags) | \
((num_entries) < 0 ? BPF_F_NO_PREALLOC : 0) | \
( (type == BPF_MAP_TYPE_LPM_TRIE || \
type == BPF_MAP_TYPE_SK_STORAGE) ? BPF_F_NO_PREALLOC : 0) \
)
#define DEFINE_BPF_MAP_BASE(the_map, TYPE, keysize, valuesize, num_entries, \
usr, grp, md, selinux, pindir, share, minkver, \
maxkver, minloader, maxloader, ignore_eng, \
ignore_user, ignore_userdebug, mapflags) \
const struct bpf_map_def SECTION("maps") the_map = { \
.type = BPF_MAP_TYPE_##TYPE, \
.key_size = (keysize), \
.value_size = (valuesize), \
.max_entries = ABSOLUTE(num_entries), \
.map_flags = DEFAULT_BPF_MAP_FLAGS(BPF_MAP_TYPE_##TYPE, num_entries, mapflags), \
.uid = (usr), \
.gid = (grp), \
.mode = (md), \
.bpfloader_min_ver = (minloader), \
.bpfloader_max_ver = (maxloader), \
.min_kver = (minkver).kver, \
.max_kver = (maxkver).kver, \
.selinux_context = (selinux), \
.pin_subdir = (pindir), \
.shared = (share).shared, \
};
// Type safe macro to declare a ring buffer and related output functions.
// Compatibility:
// * BPF ring buffers are only available kernels 5.8 and above. Any program
// accessing the ring buffer should set a program level min_kver >= 5.10,
// since 5.10 is the next LTS version.
// * The definition below sets a map min_kver of 5.10 which requires targeting
// a BPFLOADER_MIN_VER >= BPFLOADER_S_VERSION.
#define DEFINE_BPF_RINGBUF_EXT(the_map, ValueType, size_bytes, usr, grp, md, \
selinux, pindir, share, min_loader, max_loader, \
ignore_eng, ignore_user, ignore_userdebug) \
DEFINE_BPF_MAP_BASE(the_map, RINGBUF, 0, 0, size_bytes, usr, grp, md, \
selinux, pindir, share, KVER_5_10, KVER_INF, \
min_loader, max_loader, ignore_eng, ignore_user, \
ignore_userdebug, 0); \
\
_Static_assert((size_bytes) >= 4096, "min 4 kiB ringbuffer size"); \
_Static_assert((size_bytes) <= 0x10000000, "max 256 MiB ringbuffer size"); \
_Static_assert(((size_bytes) & ((size_bytes) - 1)) == 0, \
"ring buffer size must be a power of two"); \
\
static inline __always_inline __unused int bpf_##the_map##_output( \
const ValueType* v) { \
return bpf_ringbuf_output_unsafe(&the_map, v, sizeof(*v), 0); \
} \
\
static inline __always_inline __unused \
ValueType* bpf_##the_map##_reserve() { \
return bpf_ringbuf_reserve_unsafe(&the_map, sizeof(ValueType), 0); \
} \
\
static inline __always_inline __unused void bpf_##the_map##_submit( \
const ValueType* v) { \
bpf_ringbuf_submit_unsafe(v, 0); \
}
#define DEFINE_BPF_RINGBUF(the_map, ValueType, size_bytes, usr, grp, md) \
DEFINE_BPF_RINGBUF_EXT(the_map, ValueType, size_bytes, usr, grp, md, \
DEFAULT_BPF_MAP_SELINUX_CONTEXT, DEFAULT_BPF_MAP_PIN_SUBDIR, \
PRIVATE, BPFLOADER_MIN_VER, BPFLOADER_MAX_VER, \
LOAD_ON_ENG, LOAD_ON_USER, LOAD_ON_USERDEBUG)
// Type safe macro to declare a sk storage and related accessor functions.
// BPF_MAP_TYPE_SK_STORAGE was introduced in kernel 5.2 but this map requires BTF and
// BTF is enabled on kernel 5.10 or higher.
#define DEFINE_BPF_SK_STORAGE_EXT(the_map, ValueType, usr, grp, md, selinux, pindir, \
share, min_loader, max_loader, ignore_eng, \
ignore_user, ignore_userdebug, mapFlags) \
DEFINE_BPF_MAP_BASE(the_map, SK_STORAGE, sizeof(uint32_t), sizeof(ValueType), \
0, usr, grp, md, selinux, pindir, share, \
KVER_5_10, KVER_INF, min_loader, max_loader, \
ignore_eng, ignore_user, ignore_userdebug, mapFlags); \
BPF_ANNOTATE_KV_PAIR(the_map, uint32_t, ValueType); \
\
static inline __always_inline __unused ValueType* bpf_##the_map##_get( \
const struct bpf_sock* sk, const ValueType* v, unsigned long long flags) { \
return bpf_sk_storage_get_unsafe(&the_map, sk, v, flags); \
}; \
\
static inline __always_inline __unused int bpf_##the_map##_delete( \
const struct bpf_sock* sk) { \
return bpf_sk_storage_delete_unsafe(&the_map, sk); \
};
#define DEFINE_BPF_SK_STORAGE(the_map, TypeOfValue) \
DEFINE_BPF_SK_STORAGE_EXT(the_map, TypeOfValue, \
AID_ROOT, AID_NET_BW_ACCT, 0060, "fs_bpf_net_shared", "", \
PRIVATE, BPFLOADER_MIN_VER, BPFLOADER_MAX_VER, \
LOAD_ON_ENG, LOAD_ON_USER, LOAD_ON_USERDEBUG, 0)
/* There exist buggy kernels with pre-T OS, that due to
* kernel patch "[ALPS05162612] bpf: fix ubsan error"
* do not support userspace writes into non-zero index of bpf map arrays.
*
* We use this assert to prevent us from being able to define such a map.
*/
#ifdef THIS_BPF_PROGRAM_IS_FOR_TEST_PURPOSES_ONLY
#define BPF_MAP_ASSERT_OK(type, entries, mode)
#elif BPFLOADER_MIN_VER >= BPFLOADER_T_VERSION
#define BPF_MAP_ASSERT_OK(type, entries, mode)
#else
#define BPF_MAP_ASSERT_OK(type, entries, mode) \
_Static_assert(((type) != BPF_MAP_TYPE_ARRAY) || ((entries) <= 1) || !((mode) & 0222), \
"Writable arrays with more than 1 element not supported on pre-T devices.")
#endif
/* type safe macro to declare a map and related accessor functions */
#define DEFINE_BPF_MAP_EXT(the_map, TYPE, KeyType, ValueType, num_entries, usr, grp, md, \
selinux, pindir, share, min_loader, max_loader, ignore_eng, \
ignore_user, ignore_userdebug, mapFlags) \
DEFINE_BPF_MAP_BASE(the_map, TYPE, sizeof(KeyType), sizeof(ValueType), \
num_entries, usr, grp, md, selinux, pindir, share, \
KVER_NONE, KVER_INF, min_loader, max_loader, \
ignore_eng, ignore_user, ignore_userdebug, mapFlags); \
BPF_MAP_ASSERT_OK(BPF_MAP_TYPE_##TYPE, (num_entries), (md)); \
_Static_assert(sizeof(KeyType) < 1024, "aosp/2370288 requires < 1024 byte keys"); \
_Static_assert(sizeof(ValueType) < 65536, "aosp/2370288 requires < 65536 byte values"); \
BPF_ANNOTATE_KV_PAIR(the_map, KeyType, ValueType); \
\
static inline __always_inline __unused ValueType* bpf_##the_map##_lookup_elem( \
const KeyType* k) { \
return bpf_map_lookup_elem_unsafe(&the_map, k); \
}; \
\
static inline __always_inline __unused int bpf_##the_map##_update_elem( \
const KeyType* k, const ValueType* v, unsigned long long flags) { \
return bpf_map_update_elem_unsafe(&the_map, k, v, flags); \
}; \
\
static inline __always_inline __unused int bpf_##the_map##_delete_elem(const KeyType* k) { \
return bpf_map_delete_elem_unsafe(&the_map, k); \
};
#ifndef DEFAULT_BPF_MAP_SELINUX_CONTEXT
#define DEFAULT_BPF_MAP_SELINUX_CONTEXT ""
#endif
#ifndef DEFAULT_BPF_MAP_PIN_SUBDIR
#define DEFAULT_BPF_MAP_PIN_SUBDIR ""
#endif
#ifndef DEFAULT_BPF_MAP_UID
#define DEFAULT_BPF_MAP_UID AID_ROOT
#elif BPFLOADER_MIN_VER < 28u
#error "Bpf Map UID must be left at default of AID_ROOT for BpfLoader prior to v0.28"
#endif
// for maps not meant to be accessed from userspace
#define DEFINE_BPF_MAP_KERNEL_INTERNAL(the_map, TYPE, KeyType, ValueType, num_entries) \
DEFINE_BPF_MAP_EXT(the_map, TYPE, KeyType, ValueType, num_entries, AID_ROOT, AID_ROOT, \
0000, "fs_bpf_loader", "", PRIVATE, BPFLOADER_MIN_VER, BPFLOADER_MAX_VER, \
LOAD_ON_ENG, LOAD_ON_USER, LOAD_ON_USERDEBUG, 0)
#define DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, usr, grp, md) \
DEFINE_BPF_MAP_EXT(the_map, TYPE, KeyType, ValueType, num_entries, usr, grp, md, \
DEFAULT_BPF_MAP_SELINUX_CONTEXT, DEFAULT_BPF_MAP_PIN_SUBDIR, \
PRIVATE, BPFLOADER_MIN_VER, BPFLOADER_MAX_VER, \
LOAD_ON_ENG, LOAD_ON_USER, LOAD_ON_USERDEBUG, 0)
#define DEFINE_BPF_MAP(the_map, TYPE, KeyType, ValueType, num_entries) \
DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, \
DEFAULT_BPF_MAP_UID, AID_ROOT, 0600)
#define DEFINE_BPF_MAP_RO(the_map, TYPE, KeyType, ValueType, num_entries, gid) \
DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, \
DEFAULT_BPF_MAP_UID, gid, 0440)
#define DEFINE_BPF_MAP_GWO(the_map, TYPE, KeyType, ValueType, num_entries, gid) \
DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, \
DEFAULT_BPF_MAP_UID, gid, 0620)
#define DEFINE_BPF_MAP_GRO(the_map, TYPE, KeyType, ValueType, num_entries, gid) \
DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, \
DEFAULT_BPF_MAP_UID, gid, 0640)
#define DEFINE_BPF_MAP_GRW(the_map, TYPE, KeyType, ValueType, num_entries, gid) \
DEFINE_BPF_MAP_UGM(the_map, TYPE, KeyType, ValueType, num_entries, \
DEFAULT_BPF_MAP_UID, gid, 0660)
// idea from Linux include/linux/compiler_types.h (eBPF is always a 64-bit arch)
#define NATIVE_WORD(t) ((sizeof(t) == 1) || (sizeof(t) == 2) || (sizeof(t) == 4) || (sizeof(t) == 8))
// simplified from Linux include/asm-generic/rwonce.h
#define READ_ONCE(x) \
({ \
_Static_assert(NATIVE_WORD(x), "READ_ONCE requires a native word size"); \
(*(const volatile typeof(x) *)&(x)) \
})
#define WRITE_ONCE(x, value) \
do { \
_Static_assert(NATIVE_WORD(x), "WRITE_ONCE requires a native word size"); \
*(volatile typeof(x) *)&(x) = (value); \
} while (0)
// LLVM eBPF builtins: they directly generate BPF_LD_ABS/BPF_LD_IND (skb may be ignored?)
unsigned long long load_byte(void* skb, unsigned long long off) asm("llvm.bpf.load.byte");
unsigned long long load_half(void* skb, unsigned long long off) asm("llvm.bpf.load.half");
unsigned long long load_word(void* skb, unsigned long long off) asm("llvm.bpf.load.word");
static int (*bpf_probe_read)(void* dst, int size, void* unsafe_ptr) = (void*) BPF_FUNC_probe_read;
static int (*bpf_probe_read_str)(void* dst, int size, void* unsafe_ptr) = (void*) BPF_FUNC_probe_read_str;
static int (*bpf_probe_read_user)(void* dst, int size, const void* unsafe_ptr) = (void*)BPF_FUNC_probe_read_user;
static int (*bpf_probe_read_user_str)(void* dst, int size, const void* unsafe_ptr) = (void*) BPF_FUNC_probe_read_user_str;
static unsigned long long (*bpf_ktime_get_ns)(void) = (void*) BPF_FUNC_ktime_get_ns;
static unsigned long long (*bpf_ktime_get_boot_ns)(void) = (void*)BPF_FUNC_ktime_get_boot_ns;
static unsigned long long (*bpf_get_current_pid_tgid)(void) = (void*) BPF_FUNC_get_current_pid_tgid;
static unsigned long long (*bpf_get_current_uid_gid)(void) = (void*) BPF_FUNC_get_current_uid_gid;
static unsigned long long (*bpf_get_smp_processor_id)(void) = (void*) BPF_FUNC_get_smp_processor_id;
static long (*bpf_get_stackid)(void* ctx, void* map, uint64_t flags) = (void*) BPF_FUNC_get_stackid;
static long (*bpf_get_current_comm)(void* buf, uint32_t buf_size) = (void*) BPF_FUNC_get_current_comm;
// bpf_sk_fullsock requires 5.1+ kernel
static struct bpf_sock* (*bpf_sk_fullsock)(struct bpf_sock* sk) = (void*) BPF_FUNC_sk_fullsock;
// GPL only:
static int (*bpf_trace_printk)(const char* fmt, int fmt_size, ...) = (void*) BPF_FUNC_trace_printk;
#define bpf_printf(s, n...) bpf_trace_printk(s, sizeof(s), ## n)
// Note: bpf only supports up to 3 arguments, log via: bpf_printf("msg %d %d %d", 1, 2, 3);
// and read via the blocking: sudo cat /sys/kernel/debug/tracing/trace_pipe
#define DEFINE_BPF_PROG_EXT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
min_loader, max_loader, opt, selinux, pindir, ignore_eng, \
ignore_user, ignore_userdebug) \
const struct bpf_prog_def SECTION("progs") the_prog##_def = { \
.uid = (prog_uid), \
.gid = (prog_gid), \
.min_kver = (min_kv).kver, \
.max_kver = (max_kv).kver, \
.optional = (opt).optional, \
.bpfloader_min_ver = (min_loader), \
.bpfloader_max_ver = (max_loader), \
.selinux_context = (selinux), \
.pin_subdir = (pindir), \
}; \
SECTION(SECTION_NAME) \
int the_prog
#define DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
opt) \
DEFINE_BPF_PROG_EXT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
BPFLOADER_MIN_VER, BPFLOADER_MAX_VER, opt, "", "", \
LOAD_ON_ENG, LOAD_ON_USER, LOAD_ON_USERDEBUG)
// Programs (here used in the sense of functions/sections) marked optional are allowed to fail
// to load (for example due to missing kernel patches).
// The bpfloader will just ignore these failures and continue processing the next section.
//
// A non-optional program (function/section) failing to load causes a failure and aborts
// processing of the entire .o, if the .o is additionally marked critical, this will result
// in the entire bpfloader process terminating with a failure and not setting the bpf.progs_loaded
// system property. This in turn results in waitForProgsLoaded() never finishing.
//
// ie. a non-optional program in a critical .o is mandatory for kernels matching the min/max kver.
// programs requiring a kernel version >= min_kv && < max_kv
#define DEFINE_BPF_PROG_KVER_RANGE(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
MANDATORY)
#define DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, \
max_kv) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
OPTIONAL)
// programs requiring a kernel version >= min_kv
#define DEFINE_BPF_PROG_KVER(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, KVER_INF, \
MANDATORY)
#define DEFINE_OPTIONAL_BPF_PROG_KVER(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, KVER_INF, \
OPTIONAL)
// programs with no kernel version requirements
#define DEFINE_BPF_PROG(SECTION_NAME, prog_uid, prog_gid, the_prog) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, KVER_NONE, KVER_INF, \
MANDATORY)
#define DEFINE_OPTIONAL_BPF_PROG(SECTION_NAME, prog_uid, prog_gid, the_prog) \
DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, KVER_NONE, KVER_INF, \
OPTIONAL)

238
include/bpf/bpf_map_def.h Normal file
View file

@ -0,0 +1,238 @@
/*
* Copyright (C) 2020 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
/* This file is separate because it's included both by eBPF programs (via include
* in bpf_helpers.h) and directly by the boot time bpfloader (Loader.cpp).
*/
#include <linux/bpf.h>
// Pull in AID_* constants from //system/core/libcutils/include/private/android_filesystem_config.h
#include <cutils/android_filesystem_config.h>
/******************************************************************************
* *
* ! ! ! W A R N I N G ! ! ! *
* *
* CHANGES TO THESE STRUCTURE DEFINITIONS OUTSIDE OF AOSP/MAIN *WILL* BREAK *
* MAINLINE MODULE COMPATIBILITY *
* *
* AND THUS MAY RESULT IN YOUR DEVICE BRICKING AT SOME ARBITRARY POINT IN *
* THE FUTURE *
* *
* (and even in aosp/master you may only append new fields at the very end, *
* you may *never* delete fields, change their types, ordering, insert in *
* the middle, etc. If a mainline module using the old definition has *
* already shipped (which happens roughly monthly), then it's set in stone) *
* *
******************************************************************************/
/*
* The bpf_{map,prog}_def structures are compiled for different architectures.
* Once by the BPF compiler for the BPF architecture, and once by a C++
* compiler for the native Android architecture for the bpfloader.
*
* For things to work, their layout must be the same between the two.
* The BPF architecture is platform independent ('64-bit LSB bpf').
* So this effectively means these structures must be the same layout
* on 5 architectures, all of them little endian:
* 64-bit BPF, x86_64, arm and 32-bit x86 and arm
*
* As such for any types we use inside of these structs we must make sure that
* the size and alignment are the same, so the same amount of padding is used.
*
* Currently we only use: bool, enum bpf_map_type and unsigned int.
* Additionally we use char for padding.
*
* !!! WARNING: HERE BE DRAGONS !!!
*
* Be particularly careful with 64-bit integers.
* You will need to manually override their alignment to 8 bytes.
*
* To quote some parts of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69560
*
* Some types have weaker alignment requirements when they are structure members.
*
* unsigned long long on x86 is such a type.
*
* C distinguishes C11 _Alignof (the minimum alignment the type is guaranteed
* to have in all contexts, so 4, see min_align_of_type) from GNU C __alignof
* (the normal alignment of the type, so 8).
*
* alignof / _Alignof == minimum alignment required by target ABI
* __alignof / __alignof__ == preferred alignment
*
* When in a struct, apparently the minimum alignment is used.
*/
_Static_assert(sizeof(bool) == 1, "sizeof bool != 1");
_Static_assert(__alignof__(bool) == 1, "__alignof__ bool != 1");
_Static_assert(_Alignof(bool) == 1, "_Alignof bool != 1");
_Static_assert(sizeof(char) == 1, "sizeof char != 1");
_Static_assert(__alignof__(char) == 1, "__alignof__ char != 1");
_Static_assert(_Alignof(char) == 1, "_Alignof char != 1");
// This basically verifies that an enum is 'just' a 32-bit int
_Static_assert(sizeof(enum bpf_map_type) == 4, "sizeof enum bpf_map_type != 4");
_Static_assert(__alignof__(enum bpf_map_type) == 4, "__alignof__ enum bpf_map_type != 4");
_Static_assert(_Alignof(enum bpf_map_type) == 4, "_Alignof enum bpf_map_type != 4");
// Linux kernel requires sizeof(int) == 4, sizeof(void*) == sizeof(long), sizeof(long long) == 8
_Static_assert(sizeof(int) == 4, "sizeof int != 4");
_Static_assert(__alignof__(int) == 4, "__alignof__ int != 4");
_Static_assert(_Alignof(int) == 4, "_Alignof int != 4");
_Static_assert(sizeof(unsigned int) == 4, "sizeof unsigned int != 4");
_Static_assert(__alignof__(unsigned int) == 4, "__alignof__ unsigned int != 4");
_Static_assert(_Alignof(unsigned int) == 4, "_Alignof unsigned int != 4");
// We don't currently use any 64-bit types in these structs, so this is purely to document issue.
// Here sizeof & __alignof__ are consistent, but _Alignof is not: compile for 'aosp_cf_x86_phone'
_Static_assert(sizeof(unsigned long long) == 8, "sizeof unsigned long long != 8");
_Static_assert(__alignof__(unsigned long long) == 8, "__alignof__ unsigned long long != 8");
// BPF & everyone else wants 8, but 32-bit x86 wants 4
#if defined(__i386__)
_Static_assert(_Alignof(unsigned long long) == 4, "x86-32 _Alignof unsigned long long != 4");
#else
_Static_assert(_Alignof(unsigned long long) == 8, "_Alignof unsigned long long != 8");
#endif
// for maps:
struct shared_bool { bool shared; };
#define PRIVATE ((struct shared_bool){ .shared = false })
//#define SHARED ((struct shared_bool){ .shared = true })
// for programs:
struct optional_bool { bool optional; };
#define MANDATORY ((struct optional_bool){ .optional = false })
#define OPTIONAL ((struct optional_bool){ .optional = true })
// (deprecated) for both maps and programs:
struct ignore_on_eng_bool { };
#define LOAD_ON_ENG ((struct ignore_on_eng_bool){ })
struct ignore_on_user_bool { };
#define LOAD_ON_USER ((struct ignore_on_user_bool){ })
struct ignore_on_userdebug_bool { };
#define LOAD_ON_USERDEBUG ((struct ignore_on_userdebug_bool){ })
// Length of strings (incl. selinux_context and pin_subdir)
// in the bpf_map_def and bpf_prog_def structs.
//
// WARNING: YOU CANNOT *EVER* CHANGE THESE
// as this would affect the structure size in backwards incompatible ways
// and break mainline module loading on older Android T devices
#define BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE 32
#define BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE 32
/*
* Map structure to be used by Android eBPF C programs. The Android eBPF loader
* uses this structure from eBPF object to create maps at boot time.
*
* The eBPF C program should define structure in the maps section using
* SECTION("maps") otherwise it will be ignored by the eBPF loader.
*
* For example:
* const struct bpf_map_def SECTION("maps") mymap { .type=... , .key_size=... }
*
* See 'bpf_helpers.h' for helpful macros for eBPF program use.
*/
struct bpf_map_def {
enum bpf_map_type type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
unsigned int map_flags;
// The following are not supported by the Android bpfloader:
// unsigned int inner_map_idx;
// unsigned int numa_node;
unsigned int zero; // uid_t, for compat with old (buggy) bpfloader must be AID_ROOT == 0
unsigned int gid; // gid_t
unsigned int mode; // mode_t
// The following fields were added in version 0.1
unsigned int bpfloader_min_ver; // if missing, defaults to 0, ie. v0.0
unsigned int bpfloader_max_ver; // if missing, defaults to 0x10000, ie. v1.0
// The following fields were added in version 0.2 (S)
// kernelVersion() must be >= min_kver and < max_kver
unsigned int min_kver;
unsigned int max_kver;
// The following fields were added in version 0.18 (T)
//
// These are fixed length strings, padded with null bytes
//
// Warning: supported values depend on .o location
// (additionally a newer Android OS and/or bpfloader may support more values)
//
// overrides default selinux context (which is based on pin subdir)
char selinux_context[BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE];
//
// overrides default prefix (which is based on .o location)
char pin_subdir[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE];
bool shared; // use empty string as 'file' component of pin path - allows cross .o map sharing
char pad0[3]; // manually pad up to 4 byte alignment, may be used for extensions in the future
unsigned int uid; // uid_t
};
_Static_assert(sizeof(((struct bpf_map_def *)0)->selinux_context) == 32, "must be 32 bytes");
_Static_assert(sizeof(((struct bpf_map_def *)0)->pin_subdir) == 32, "must be 32 bytes");
// This needs to be updated whenever the above structure definition is expanded.
_Static_assert(sizeof(struct bpf_map_def) == 120, "sizeof struct bpf_map_def != 120");
_Static_assert(__alignof__(struct bpf_map_def) == 4, "__alignof__ struct bpf_map_def != 4");
_Static_assert(_Alignof(struct bpf_map_def) == 4, "_Alignof struct bpf_map_def != 4");
struct bpf_prog_def {
unsigned int uid;
unsigned int gid;
// kernelVersion() must be >= min_kver and < max_kver
unsigned int min_kver;
unsigned int max_kver;
bool optional; // program section (ie. function) may fail to load, continue onto next func.
char pad0[3]; // manually pad up to 4 byte alignment, may be used for extensions in the future
// The following fields were added in version 0.1
unsigned int bpfloader_min_ver; // if missing, defaults to 0, ie. v0.0
unsigned int bpfloader_max_ver; // if missing, defaults to 0x10000, ie. v1.0
// The following fields were added in version 0.18, see description up above in bpf_map_def
char selinux_context[BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE];
char pin_subdir[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE];
};
_Static_assert(sizeof(((struct bpf_prog_def *)0)->selinux_context) == 32, "must be 32 bytes");
_Static_assert(sizeof(((struct bpf_prog_def *)0)->pin_subdir) == 32, "must be 32 bytes");
// This needs to be updated whenever the above structure definition is expanded.
_Static_assert(sizeof(struct bpf_prog_def) == 92, "sizeof struct bpf_prog_def != 92");
_Static_assert(__alignof__(struct bpf_prog_def) == 4, "__alignof__ struct bpf_prog_def != 4");
_Static_assert(_Alignof(struct bpf_prog_def) == 4, "_Alignof struct bpf_prog_def != 4");

5
progs/Android.bp
View file

@ -27,11 +27,6 @@ cc_library_headers {
export_include_dirs: ["include"],
}
bpf {
name: "bpfRingbufProg.o",
srcs: ["bpfRingbufProg.c"],
}
libbpf_prog {
name: "bpfRingbufProg.bpf",
srcs: ["bpfRingbufProg.c"],