[RFC 5/5] tap: stop "vendoring" linux bpf header

[Stephen Hemminger <stephen@networkplumber.org>]

The proper place for finding bpf structures and functions is
in linux/bpf.h. The original version was trying to workaround the
case where the build environment was running on old pre BPF
version of Glibc, but the target environment had BPF. This is not
a supportable build method, and not how rest of DPDK works.

Having own private (and divergent) version headers leads to future
problems when BPF definitions evolve.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/tap/bpf/bpf_extract.py |   1 -
 drivers/net/tap/tap_bpf.h          | 118 -----------------------------
 drivers/net/tap/tap_bpf_api.c      |  16 ++--
 drivers/net/tap/tap_bpf_insns.h    |   1 -
 4 files changed, 9 insertions(+), 127 deletions(-)
 delete mode 100644 drivers/net/tap/tap_bpf.h

diff --git a/drivers/net/tap/bpf/bpf_extract.py b/drivers/net/tap/bpf/bpf_extract.py
index b630c42b809f..73c4dafe4eca 100644
--- a/drivers/net/tap/bpf/bpf_extract.py
+++ b/drivers/net/tap/bpf/bpf_extract.py
@@ -65,7 +65,6 @@ def write_header(out, source):
         print(f' * Auto-generated from {source}', file=out)
     print(" * This not the original source file. Do NOT edit it.", file=out)
     print(" */\n", file=out)
-    print("#include <tap_bpf.h>", file=out)
 
 
 def main():
diff --git a/drivers/net/tap/tap_bpf.h b/drivers/net/tap/tap_bpf.h
deleted file mode 100644
index aa5a733525e1..000000000000
--- a/drivers/net/tap/tap_bpf.h
+++ /dev/null
@@ -1,118 +0,0 @@
-/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
- * Copyright 2017 Mellanox Technologies, Ltd
- */
-
-#ifndef __TAP_BPF_H__
-#define __TAP_BPF_H__
-
-#include <tap_autoconf.h>
-
-/* Do not #include <linux/bpf.h> since eBPF must compile on different
- * distros which may include partial definitions for eBPF (while the
- * kernel itself may support eBPF). Instead define here all that is needed
- */
-
-/* BPF_MAP_UPDATE_ELEM command flags */
-#define	BPF_ANY	0 /* create a new element or update an existing */
-
-/* BPF architecture instruction struct */
-struct bpf_insn {
-	__u8	code;
-	__u8	dst_reg:4;
-	__u8	src_reg:4;
-	__s16	off;
-	__s32	imm; /* immediate value */
-};
-
-/* BPF program types */
-enum bpf_prog_type {
-	BPF_PROG_TYPE_UNSPEC,
-	BPF_PROG_TYPE_SOCKET_FILTER,
-	BPF_PROG_TYPE_KPROBE,
-	BPF_PROG_TYPE_SCHED_CLS,
-	BPF_PROG_TYPE_SCHED_ACT,
-};
-
-/* BPF commands types */
-enum bpf_cmd {
-	BPF_MAP_CREATE,
-	BPF_MAP_LOOKUP_ELEM,
-	BPF_MAP_UPDATE_ELEM,
-	BPF_MAP_DELETE_ELEM,
-	BPF_MAP_GET_NEXT_KEY,
-	BPF_PROG_LOAD,
-};
-
-/* BPF maps types */
-enum bpf_map_type {
-	BPF_MAP_TYPE_UNSPEC,
-	BPF_MAP_TYPE_HASH,
-};
-
-/* union of anonymous structs used with TAP BPF commands */
-union bpf_attr {
-	/* BPF_MAP_CREATE command */
-	struct {
-		__u32	map_type;
-		__u32	key_size;
-		__u32	value_size;
-		__u32	max_entries;
-		__u32	map_flags;
-		__u32	inner_map_fd;
-	};
-
-	/* BPF_MAP_UPDATE_ELEM, BPF_MAP_DELETE_ELEM commands */
-	struct {
-		__u32		map_fd;
-		__aligned_u64	key;
-		union {
-			__aligned_u64 value;
-			__aligned_u64 next_key;
-		};
-		__u64		flags;
-	};
-
-	/* BPF_PROG_LOAD command */
-	struct {
-		__u32		prog_type;
-		__u32		insn_cnt;
-		__aligned_u64	insns;
-		__aligned_u64	license;
-		__u32		log_level;
-		__u32		log_size;
-		__aligned_u64	log_buf;
-		__u32		kern_version;
-		__u32		prog_flags;
-	};
-} __rte_aligned(8);
-
-#ifndef __NR_bpf
-# if defined(__i386__)
-#  define __NR_bpf 357
-# elif defined(__x86_64__)
-#  define __NR_bpf 321
-# elif defined(__arm__)
-#  define __NR_bpf 386
-# elif defined(__aarch64__)
-#  define __NR_bpf 280
-# elif defined(__sparc__)
-#  define __NR_bpf 349
-# elif defined(__s390__)
-#  define __NR_bpf 351
-# elif defined(__powerpc__)
-#  define __NR_bpf 361
-# elif defined(__riscv)
-#  define __NR_bpf 280
-# elif defined(__loongarch__)
-#  define __NR_bpf 280
-# else
-#  error __NR_bpf not defined
-# endif
-#endif
-
-enum {
-	BPF_MAP_ID_KEY,
-	BPF_MAP_ID_SIMPLE,
-};
-
-#endif /* __TAP_BPF_H__ */
diff --git a/drivers/net/tap/tap_bpf_api.c b/drivers/net/tap/tap_bpf_api.c
index 29223b7f0ea7..54e469ebf5ff 100644
--- a/drivers/net/tap/tap_bpf_api.c
+++ b/drivers/net/tap/tap_bpf_api.c
@@ -2,17 +2,13 @@
  * Copyright 2017 Mellanox Technologies, Ltd
  */
 
-#include <errno.h>
-#include <string.h>
 #include <unistd.h>
-#include <sys/queue.h>
+#include <syscall.h>
+#include <linux/bpf.h>
 
-#include <rte_malloc.h>
-#include <rte_eth_tap.h>
 #include <tap_flow.h>
 #include <tap_autoconf.h>
-#include <tap_tcmsgs.h>
-#include <tap_bpf.h>
+
 #include <tap_bpf_insns.h>
 
 static int bpf_load(enum bpf_prog_type type,
@@ -106,7 +102,13 @@ static inline __u64 ptr_to_u64(const void *ptr)
 static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
 			unsigned int size)
 {
+#ifdef __NR_bpf
 	return syscall(__NR_bpf, cmd, attr, size);
+#else
+	fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
+	errno = ENOSYS;
+	return -1;
+#endif
 }
 
 /**
diff --git a/drivers/net/tap/tap_bpf_insns.h b/drivers/net/tap/tap_bpf_insns.h
index 53fa76c4e6b0..88aec6885a06 100644
--- a/drivers/net/tap/tap_bpf_insns.h
+++ b/drivers/net/tap/tap_bpf_insns.h
@@ -3,7 +3,6 @@
  * This not the original source file. Do NOT edit it.
  */
 
-#include <tap_bpf.h>
 
 static struct bpf_insn cls_q_insns[] = {
 	{0x61,    2,    1,       52, 0x00000000},
-- 
2.43.0