tools/lib/bpf/bpf_helpers.h - linux - Git at Google

 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
 #ifndef __BPF_HELPERS__
 #define __BPF_HELPERS__

 /*
  * Note that bpf programs need to include either
  * vmlinux.h (auto-generated from BTF) or linux/types.h
  * in advance since bpf_helper_defs.h uses such types
  * as __u64.
  */
 #include "bpf_helper_defs.h"

 #define __uint(name, val) int (*name)[val]
 #define __type(name, val) typeof(val) *name
 #define __array(name, val) typeof(val) *name[]

 /*
  * Helper macro to place programs, maps, license in
  * different sections in elf_bpf file. Section names
  * are interpreted by libbpf depending on the context (BPF programs, BPF maps,
  * extern variables, etc).
  * To allow use of SEC() with externs (e.g., for extern .maps declarations),
  * make sure __attribute__((unused)) doesn't trigger compilation warning.
  */
 #define SEC(name) \
 	_Pragma("GCC diagnostic push")					    \
 	_Pragma("GCC diagnostic ignored \"-Wignored-attributes\"")	    \
 	__attribute__((section(name), used))				    \
 	_Pragma("GCC diagnostic pop")					    \

 /* Avoid 'linux/stddef.h' definition of '__always_inline'. */
 #undef __always_inline
 #define __always_inline inline __attribute__((always_inline))

 #ifndef __noinline
 #define __noinline __attribute__((noinline))
 #endif
 #ifndef __weak
 #define __weak __attribute__((weak))
 #endif

 /*
  * Use __hidden attribute to mark a non-static BPF subprogram effectively
  * static for BPF verifier's verification algorithm purposes, allowing more
  * extensive and permissive BPF verification process, taking into account
  * subprogram's caller context.
  */
 #define __hidden __attribute__((visibility("hidden")))

 /* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
  * any system-level headers (such as stddef.h, linux/version.h, etc), and
  * commonly-used macros like NULL and KERNEL_VERSION aren't available through
  * vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
  * them on their own. So as a convenience, provide such definitions here.
  */
 #ifndef NULL
 #define NULL ((void *)0)
 #endif

 #ifndef KERNEL_VERSION
 #define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
 #endif

 /*
  * Helper macros to manipulate data structures
  */
 #ifndef offsetof
 #define offsetof(TYPE, MEMBER)	((unsigned long)&((TYPE *)0)->MEMBER)
 #endif
 #ifndef container_of
 #define container_of(ptr, type, member)				\
 	({							\
 		void *__mptr = (void *)(ptr);			\
 		((type *)(__mptr - offsetof(type, member)));	\
 	})
 #endif

 /*
  * Helper macro to throw a compilation error if __bpf_unreachable() gets
  * built into the resulting code. This works given BPF back end does not
  * implement __builtin_trap(). This is useful to assert that certain paths
  * of the program code are never used and hence eliminated by the compiler.
  *
  * For example, consider a switch statement that covers known cases used by
  * the program. __bpf_unreachable() can then reside in the default case. If
  * the program gets extended such that a case is not covered in the switch
  * statement, then it will throw a build error due to the default case not
  * being compiled out.
  */
 #ifndef __bpf_unreachable
 # define __bpf_unreachable()	__builtin_trap()
 #endif

 /*
  * Helper function to perform a tail call with a constant/immediate map slot.
  */
 #if __clang_major__ >= 8 && defined(__bpf__)
 static __always_inline void
 bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 {
 	if (!__builtin_constant_p(slot))
 		__bpf_unreachable();

 	/*
 	 * Provide a hard guarantee that LLVM won't optimize setting r2 (map
 	 * pointer) and r3 (constant map index) from _different paths_ ending
 	 * up at the _same_ call insn as otherwise we won't be able to use the
 	 * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
 	 * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
 	 * tracking for prog array pokes") for details on verifier tracking.
 	 *
 	 * Note on clobber list: we need to stay in-line with BPF calling
 	 * convention, so even if we don't end up using r0, r4, r5, we need
 	 * to mark them as clobber so that LLVM doesn't end up using them
 	 * before / after the call.
 	 */
 	asm volatile("r1 = %[ctx]\n\t"
 		     "r2 = %[map]\n\t"
 		     "r3 = %[slot]\n\t"
 		     "call 12"
 		     :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
 		     : "r0", "r1", "r2", "r3", "r4", "r5");
 }
 #endif

 /*
  * Helper structure used by eBPF C program
  * to describe BPF map attributes to libbpf loader
  */
 struct bpf_map_def {
 	unsigned int type;
 	unsigned int key_size;
 	unsigned int value_size;
 	unsigned int max_entries;
 	unsigned int map_flags;
 };

 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
 	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
 	LIBBPF_PIN_BY_NAME,
 };

 enum libbpf_tristate {
 	TRI_NO = 0,
 	TRI_YES = 1,
 	TRI_MODULE = 2,
 };

 #define __kconfig __attribute__((section(".kconfig")))
 #define __ksym __attribute__((section(".ksyms")))

 #ifndef ___bpf_concat
 #define ___bpf_concat(a, b) a ## b
 #endif
 #ifndef ___bpf_apply
 #define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
 #endif
 #ifndef ___bpf_nth
 #define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
 #endif
 #ifndef ___bpf_narg
 #define ___bpf_narg(...) \
 	___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
 #endif

 #define ___bpf_fill0(arr, p, x) do {} while (0)
 #define ___bpf_fill1(arr, p, x) arr[p] = x
 #define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
 #define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
 #define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
 #define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
 #define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
 #define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
 #define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
 #define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
 #define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
 #define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
 #define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
 #define ___bpf_fill(arr, args...) \
 	___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)

 /*
  * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
  * in a structure.
  */
 #define BPF_SEQ_PRINTF(seq, fmt, args...)			\
 ({								\
 	static const char ___fmt[] = fmt;			\
 	unsigned long long ___param[___bpf_narg(args)];		\
 								\
 	_Pragma("GCC diagnostic push")				\
 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
 	___bpf_fill(___param, args);				\
 	_Pragma("GCC diagnostic pop")				\
 								\
 	bpf_seq_printf(seq, ___fmt, sizeof(___fmt),		\
 		       ___param, sizeof(___param));		\
 })

 /*
  * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
  * an array of u64.
  */
 #define BPF_SNPRINTF(out, out_size, fmt, args...)		\
 ({								\
 	static const char ___fmt[] = fmt;			\
 	unsigned long long ___param[___bpf_narg(args)];		\
 								\
 	_Pragma("GCC diagnostic push")				\
 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
 	___bpf_fill(___param, args);				\
 	_Pragma("GCC diagnostic pop")				\
 								\
 	bpf_snprintf(out, out_size, ___fmt,			\
 		     ___param, sizeof(___param));		\
 })

 #ifdef BPF_NO_GLOBAL_DATA
 #define BPF_PRINTK_FMT_MOD
 #else
 #define BPF_PRINTK_FMT_MOD static const
 #endif

 #define __bpf_printk(fmt, ...)				\
 ({							\
 	BPF_PRINTK_FMT_MOD char ____fmt[] = fmt;	\
 	bpf_trace_printk(____fmt, sizeof(____fmt),	\
 			 ##__VA_ARGS__);		\
 })

 /*
  * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
  * instead of an array of u64.
  */
 #define __bpf_vprintk(fmt, args...)				\
 ({								\
 	static const char ___fmt[] = fmt;			\
 	unsigned long long ___param[___bpf_narg(args)];		\
 								\
 	_Pragma("GCC diagnostic push")				\
 	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
 	___bpf_fill(___param, args);				\
 	_Pragma("GCC diagnostic pop")				\
 								\
 	bpf_trace_vprintk(___fmt, sizeof(___fmt),		\
 			  ___param, sizeof(___param));		\
 })

 /* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
  * Otherwise use __bpf_vprintk
  */
 #define ___bpf_pick_printk(...) \
 	___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,	\
 		   __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,		\
 		   __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\
 		   __bpf_printk /*1*/, __bpf_printk /*0*/)

 /* Helper macro to print out debug messages */
 #define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)

 #endif
	/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
	#ifndef __BPF_HELPERS__
	#define __BPF_HELPERS__

	/*
	* Note that bpf programs need to include either
	* vmlinux.h (auto-generated from BTF) or linux/types.h
	* in advance since bpf_helper_defs.h uses such types
	* as __u64.
	*/
	#include "bpf_helper_defs.h"

	#define __uint(name, val) int (*name)[val]
	#define __type(name, val) typeof(val) *name
	#define __array(name, val) typeof(val) *name[]

	/*
	* Helper macro to place programs, maps, license in
	* different sections in elf_bpf file. Section names
	* are interpreted by libbpf depending on the context (BPF programs, BPF maps,
	* extern variables, etc).
	* To allow use of SEC() with externs (e.g., for extern .maps declarations),
	* make sure __attribute__((unused)) doesn't trigger compilation warning.
	*/
	#define SEC(name) \
	_Pragma("GCC diagnostic push") \
	_Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
	__attribute__((section(name), used)) \
	_Pragma("GCC diagnostic pop") \

	/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
	#undef __always_inline
	#define __always_inline inline __attribute__((always_inline))

	#ifndef __noinline
	#define __noinline __attribute__((noinline))
	#endif
	#ifndef __weak
	#define __weak __attribute__((weak))
	#endif

	/*
	* Use __hidden attribute to mark a non-static BPF subprogram effectively
	* static for BPF verifier's verification algorithm purposes, allowing more
	* extensive and permissive BPF verification process, taking into account
	* subprogram's caller context.
	*/
	#define __hidden __attribute__((visibility("hidden")))

	/* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
	* any system-level headers (such as stddef.h, linux/version.h, etc), and
	* commonly-used macros like NULL and KERNEL_VERSION aren't available through
	* vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
	* them on their own. So as a convenience, provide such definitions here.
	*/
	#ifndef NULL
	#define NULL ((void *)0)
	#endif

	#ifndef KERNEL_VERSION
	#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
	#endif

	/*
	* Helper macros to manipulate data structures
	*/
	#ifndef offsetof
	#define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER)
	#endif
	#ifndef container_of
	#define container_of(ptr, type, member) \
	({ \
	void __mptr = (void )(ptr); \
	((type *)(__mptr - offsetof(type, member))); \
	})
	#endif

	/*
	* Helper macro to throw a compilation error if __bpf_unreachable() gets
	* built into the resulting code. This works given BPF back end does not
	* implement __builtin_trap(). This is useful to assert that certain paths
	* of the program code are never used and hence eliminated by the compiler.
	*
	* For example, consider a switch statement that covers known cases used by
	* the program. __bpf_unreachable() can then reside in the default case. If
	* the program gets extended such that a case is not covered in the switch
	* statement, then it will throw a build error due to the default case not
	* being compiled out.
	*/
	#ifndef __bpf_unreachable
	# define __bpf_unreachable() __builtin_trap()
	#endif

	/*
	* Helper function to perform a tail call with a constant/immediate map slot.
	*/
	#if __clang_major__ >= 8 && defined(__bpf__)
	static __always_inline void
	bpf_tail_call_static(void ctx, const void map, const __u32 slot)
	{
	if (!__builtin_constant_p(slot))
	__bpf_unreachable();

	/*
	* Provide a hard guarantee that LLVM won't optimize setting r2 (map
	* pointer) and r3 (constant map index) from _different paths_ ending
	* up at the _same_ call insn as otherwise we won't be able to use the
	* jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
	* given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
	* tracking for prog array pokes") for details on verifier tracking.
	*
	* Note on clobber list: we need to stay in-line with BPF calling
	* convention, so even if we don't end up using r0, r4, r5, we need
	* to mark them as clobber so that LLVM doesn't end up using them
	* before / after the call.
	*/
	asm volatile("r1 = %[ctx]\n\t"
	"r2 = %[map]\n\t"
	"r3 = %[slot]\n\t"
	"call 12"
	:: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
	: "r0", "r1", "r2", "r3", "r4", "r5");
	}
	#endif

	/*
	* Helper structure used by eBPF C program
	* to describe BPF map attributes to libbpf loader
	*/
	struct bpf_map_def {
	unsigned int type;
	unsigned int key_size;
	unsigned int value_size;
	unsigned int max_entries;
	unsigned int map_flags;
	};

	enum libbpf_pin_type {
	LIBBPF_PIN_NONE,
	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
	LIBBPF_PIN_BY_NAME,
	};

	enum libbpf_tristate {
	TRI_NO = 0,
	TRI_YES = 1,
	TRI_MODULE = 2,
	};

	#define __kconfig __attribute__((section(".kconfig")))
	#define __ksym __attribute__((section(".ksyms")))

	#ifndef ___bpf_concat
	#define ___bpf_concat(a, b) a ## b
	#endif
	#ifndef ___bpf_apply
	#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
	#endif
	#ifndef ___bpf_nth
	#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
	#endif
	#ifndef ___bpf_narg
	#define ___bpf_narg(...) \
	___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
	#endif

	#define ___bpf_fill0(arr, p, x) do {} while (0)
	#define ___bpf_fill1(arr, p, x) arr[p] = x
	#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
	#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
	#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
	#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
	#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
	#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
	#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
	#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
	#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
	#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
	#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
	#define ___bpf_fill(arr, args...) \
	___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)

	/*
	* BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
	* in a structure.
	*/
	#define BPF_SEQ_PRINTF(seq, fmt, args...) \
	({ \
	static const char ___fmt[] = fmt; \
	unsigned long long ___param[___bpf_narg(args)]; \
	\
	_Pragma("GCC diagnostic push") \
	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
	___bpf_fill(___param, args); \
	_Pragma("GCC diagnostic pop") \
	\
	bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
	___param, sizeof(___param)); \
	})

	/*
	* BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
	* an array of u64.
	*/
	#define BPF_SNPRINTF(out, out_size, fmt, args...) \
	({ \
	static const char ___fmt[] = fmt; \
	unsigned long long ___param[___bpf_narg(args)]; \
	\
	_Pragma("GCC diagnostic push") \
	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
	___bpf_fill(___param, args); \
	_Pragma("GCC diagnostic pop") \
	\
	bpf_snprintf(out, out_size, ___fmt, \
	___param, sizeof(___param)); \
	})

	#ifdef BPF_NO_GLOBAL_DATA
	#define BPF_PRINTK_FMT_MOD
	#else
	#define BPF_PRINTK_FMT_MOD static const
	#endif

	#define __bpf_printk(fmt, ...) \
	({ \
	BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \
	bpf_trace_printk(____fmt, sizeof(____fmt), \
	##__VA_ARGS__); \
	})

	/*
	* __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
	* instead of an array of u64.
	*/
	#define __bpf_vprintk(fmt, args...) \
	({ \
	static const char ___fmt[] = fmt; \
	unsigned long long ___param[___bpf_narg(args)]; \
	\
	_Pragma("GCC diagnostic push") \
	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
	___bpf_fill(___param, args); \
	_Pragma("GCC diagnostic pop") \
	\
	bpf_trace_vprintk(___fmt, sizeof(___fmt), \
	___param, sizeof(___param)); \
	})

	/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
	* Otherwise use __bpf_vprintk
	*/
	#define ___bpf_pick_printk(...) \
	___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
	__bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
	__bpf_vprintk, __bpf_vprintk, __bpf_printk /3/, __bpf_printk /2/,\
	__bpf_printk /1/, __bpf_printk /0/)

	/* Helper macro to print out debug messages */
	#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)

	#endif