get rid of version checks

version checks don't work at all on kernels with backported bpf bits
they also fail when /usr/include/linux/bpf.h doesn't match loaded
kernel.
Fix these issues by embedding bpf.h into libbcc.so and force load it
in clang, so we can remove all version checks and rely on verifier
complaining on unknown function call.
Later patch can make verifier errors less cryptic by converting
'unknown call 12' to strings.

while at it update bpf.h to the latest.
Signed-off-by: Alexei Starovoitov <ast@fb.com>

src/cc/compat/linux/bpf.h

@@ -101,12 +101,15 @@ enum bpf_prog_type {
 #define BPF_NOEXIST	1 /* create new element if it didn't exist */
 #define BPF_EXIST	2 /* update existing element */
 
+#define BPF_F_NO_PREALLOC	(1U << 0)
+
 union bpf_attr {
 	struct { /* anonymous struct used by BPF_MAP_CREATE command */
 		__u32	map_type;	/* one of enum bpf_map_type */
 		__u32	key_size;	/* size of key in bytes */
 		__u32	value_size;	/* size of value in bytes */
 		__u32	max_entries;	/* max number of entries in a map */
+		__u32	map_flags;	/* prealloc or not */
 	};
 
 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -298,6 +301,17 @@ enum bpf_func_id {
 	 * Return: csum result
 	 */
 	BPF_FUNC_csum_diff,
+
+	/**
+	 * bpf_skb_[gs]et_tunnel_opt(skb, opt, size)
+	 * retrieve or populate tunnel options metadata
+	 * @skb: pointer to skb
+	 * @opt: pointer to raw tunnel option data
+	 * @size: size of @opt
+	 * Return: 0 on success for set, option size for get
+	 */
+	BPF_FUNC_skb_get_tunnel_opt,
+	BPF_FUNC_skb_set_tunnel_opt,
 	__BPF_FUNC_MAX_ID,
 };
 
@@ -305,6 +319,7 @@ enum bpf_func_id {
 
 /* BPF_FUNC_skb_store_bytes flags. */
 #define BPF_F_RECOMPUTE_CSUM		(1ULL << 0)
+#define BPF_F_INVALIDATE_HASH		(1ULL << 1)
 
 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
  * First 4 bits are for passing the header field size.
@@ -327,6 +342,10 @@ enum bpf_func_id {
 #define BPF_F_FAST_STACK_CMP		(1ULL << 9)
 #define BPF_F_REUSE_STACKID		(1ULL << 10)
 
+/* BPF_FUNC_skb_set_tunnel_key flags. */
+#define BPF_F_ZERO_CSUM_TX		(1ULL << 1)
+#define BPF_F_DONT_FRAGMENT		(1ULL << 2)
+
 /* user accessible mirror of in-kernel sk_buff.
  * new fields can only be added to the end of this structure
  */
@@ -356,6 +375,8 @@ struct bpf_tunnel_key {
 	};
 	__u8 tunnel_tos;
 	__u8 tunnel_ttl;
+	__u16 tunnel_ext;
+	__u32 tunnel_label;
 };
 
 #endif /* _UAPI__LINUX_BPF_H__ */

src/cc/compat/linux/virtual_bpf.h

+R"********(
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#ifndef _UAPI__LINUX_BPF_H__
+#define _UAPI__LINUX_BPF_H__
+
+#include <linux/types.h>
+#include <linux/bpf_common.h>
+
+/* Extended instruction set based on top of classic BPF */
+
+/* instruction classes */
+#define BPF_ALU64	0x07	/* alu mode in double word width */
+
+/* ld/ldx fields */
+#define BPF_DW		0x18	/* double word */
+#define BPF_XADD	0xc0	/* exclusive add */
+
+/* alu/jmp fields */
+#define BPF_MOV		0xb0	/* mov reg to reg */
+#define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
+
+/* change endianness of a register */
+#define BPF_END		0xd0	/* flags for endianness conversion: */
+#define BPF_TO_LE	0x00	/* convert to little-endian */
+#define BPF_TO_BE	0x08	/* convert to big-endian */
+#define BPF_FROM_LE	BPF_TO_LE
+#define BPF_FROM_BE	BPF_TO_BE
+
+#define BPF_JNE		0x50	/* jump != */
+#define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
+#define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
+#define BPF_CALL	0x80	/* function call */
+#define BPF_EXIT	0x90	/* function return */
+
+/* Register numbers */
+enum {
+	BPF_REG_0 = 0,
+	BPF_REG_1,
+	BPF_REG_2,
+	BPF_REG_3,
+	BPF_REG_4,
+	BPF_REG_5,
+	BPF_REG_6,
+	BPF_REG_7,
+	BPF_REG_8,
+	BPF_REG_9,
+	BPF_REG_10,
+	__MAX_BPF_REG,
+};
+
+/* BPF has 10 general purpose 64-bit registers and stack frame. */
+#define MAX_BPF_REG	__MAX_BPF_REG
+
+struct bpf_insn {
+	__u8	code;		/* opcode */
+	__u8	dst_reg:4;	/* dest register */
+	__u8	src_reg:4;	/* source register */
+	__s16	off;		/* signed offset */
+	__s32	imm;		/* signed immediate constant */
+};
+
+/* BPF syscall commands, see bpf(2) man-page for details. */
+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_OBJ_PIN,
+	BPF_OBJ_GET,
+};
+
+enum bpf_map_type {
+	BPF_MAP_TYPE_UNSPEC,
+	BPF_MAP_TYPE_HASH,
+	BPF_MAP_TYPE_ARRAY,
+	BPF_MAP_TYPE_PROG_ARRAY,
+	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+	BPF_MAP_TYPE_PERCPU_HASH,
+	BPF_MAP_TYPE_PERCPU_ARRAY,
+	BPF_MAP_TYPE_STACK_TRACE,
+};
+
+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,
+};
+
+#define BPF_PSEUDO_MAP_FD	1
+
+/* flags for BPF_MAP_UPDATE_ELEM command */
+#define BPF_ANY		0 /* create new element or update existing */
+#define BPF_NOEXIST	1 /* create new element if it didn't exist */
+#define BPF_EXIST	2 /* update existing element */
+
+#define BPF_F_NO_PREALLOC	(1U << 0)
+
+union bpf_attr {
+	struct { /* anonymous struct used by BPF_MAP_CREATE command */
+		__u32	map_type;	/* one of enum bpf_map_type */
+		__u32	key_size;	/* size of key in bytes */
+		__u32	value_size;	/* size of value in bytes */
+		__u32	max_entries;	/* max number of entries in a map */
+		__u32	map_flags;	/* prealloc or not */
+	};
+
+	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
+		__u32		map_fd;
+		__aligned_u64	key;
+		union {
+			__aligned_u64 value;
+			__aligned_u64 next_key;
+		};
+		__u64		flags;
+	};
+
+	struct { /* anonymous struct used by BPF_PROG_LOAD command */
+		__u32		prog_type;	/* one of enum bpf_prog_type */
+		__u32		insn_cnt;
+		__aligned_u64	insns;
+		__aligned_u64	license;
+		__u32		log_level;	/* verbosity level of verifier */
+		__u32		log_size;	/* size of user buffer */
+		__aligned_u64	log_buf;	/* user supplied buffer */
+		__u32		kern_version;	/* checked when prog_type=kprobe */
+	};
+
+	struct { /* anonymous struct used by BPF_OBJ_* commands */
+		__aligned_u64	pathname;
+		__u32		bpf_fd;
+	};
+} __attribute__((aligned(8)));
+
+/* integer value in 'imm' field of BPF_CALL instruction selects which helper
+ * function eBPF program intends to call
+ */
+enum bpf_func_id {
+	BPF_FUNC_unspec,
+	BPF_FUNC_map_lookup_elem, /* void *map_lookup_elem(&map, &key) */
+	BPF_FUNC_map_update_elem, /* int map_update_elem(&map, &key, &value, flags) */
+	BPF_FUNC_map_delete_elem, /* int map_delete_elem(&map, &key) */
+	BPF_FUNC_probe_read,      /* int bpf_probe_read(void *dst, int size, void *src) */
+	BPF_FUNC_ktime_get_ns,    /* u64 bpf_ktime_get_ns(void) */
+	BPF_FUNC_trace_printk,    /* int bpf_trace_printk(const char *fmt, int fmt_size, ...) */
+	BPF_FUNC_get_prandom_u32, /* u32 prandom_u32(void) */
+	BPF_FUNC_get_smp_processor_id, /* u32 raw_smp_processor_id(void) */
+
+	/**
+	 * skb_store_bytes(skb, offset, from, len, flags) - store bytes into packet
+	 * @skb: pointer to skb
+	 * @offset: offset within packet from skb->mac_header
+	 * @from: pointer where to copy bytes from
+	 * @len: number of bytes to store into packet
+	 * @flags: bit 0 - if true, recompute skb->csum
+	 *         other bits - reserved
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_skb_store_bytes,
+
+	/**
+	 * l3_csum_replace(skb, offset, from, to, flags) - recompute IP checksum
+	 * @skb: pointer to skb
+	 * @offset: offset within packet where IP checksum is located
+	 * @from: old value of header field
+	 * @to: new value of header field
+	 * @flags: bits 0-3 - size of header field
+	 *         other bits - reserved
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_l3_csum_replace,
+
+	/**
+	 * l4_csum_replace(skb, offset, from, to, flags) - recompute TCP/UDP checksum
+	 * @skb: pointer to skb
+	 * @offset: offset within packet where TCP/UDP checksum is located
+	 * @from: old value of header field
+	 * @to: new value of header field
+	 * @flags: bits 0-3 - size of header field
+	 *         bit 4 - is pseudo header
+	 *         other bits - reserved
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_l4_csum_replace,
+
+	/**
+	 * bpf_tail_call(ctx, prog_array_map, index) - jump into another BPF program
+	 * @ctx: context pointer passed to next program
+	 * @prog_array_map: pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY
+	 * @index: index inside array that selects specific program to run
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_tail_call,
+
+	/**
+	 * bpf_clone_redirect(skb, ifindex, flags) - redirect to another netdev
+	 * @skb: pointer to skb
+	 * @ifindex: ifindex of the net device
+	 * @flags: bit 0 - if set, redirect to ingress instead of egress
+	 *         other bits - reserved
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_clone_redirect,
+
+	/**
+	 * u64 bpf_get_current_pid_tgid(void)
+	 * Return: current->tgid << 32 | current->pid
+	 */
+	BPF_FUNC_get_current_pid_tgid,
+
+	/**
+	 * u64 bpf_get_current_uid_gid(void)
+	 * Return: current_gid << 32 | current_uid
+	 */
+	BPF_FUNC_get_current_uid_gid,
+
+	/**
+	 * bpf_get_current_comm(char *buf, int size_of_buf)
+	 * stores current->comm into buf
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_get_current_comm,
+
+	/**
+	 * bpf_get_cgroup_classid(skb) - retrieve a proc's classid
+	 * @skb: pointer to skb
+	 * Return: classid if != 0
+	 */
+	BPF_FUNC_get_cgroup_classid,
+	BPF_FUNC_skb_vlan_push, /* bpf_skb_vlan_push(skb, vlan_proto, vlan_tci) */
+	BPF_FUNC_skb_vlan_pop,  /* bpf_skb_vlan_pop(skb) */
+
+	/**
+	 * bpf_skb_[gs]et_tunnel_key(skb, key, size, flags)
+	 * retrieve or populate tunnel metadata
+	 * @skb: pointer to skb
+	 * @key: pointer to 'struct bpf_tunnel_key'
+	 * @size: size of 'struct bpf_tunnel_key'
+	 * @flags: room for future extensions
+	 * Retrun: 0 on success
+	 */
+	BPF_FUNC_skb_get_tunnel_key,
+	BPF_FUNC_skb_set_tunnel_key,
+	BPF_FUNC_perf_event_read,	/* u64 bpf_perf_event_read(&map, index) */
+	/**
+	 * bpf_redirect(ifindex, flags) - redirect to another netdev
+	 * @ifindex: ifindex of the net device
+	 * @flags: bit 0 - if set, redirect to ingress instead of egress
+	 *         other bits - reserved
+	 * Return: TC_ACT_REDIRECT
+	 */
+	BPF_FUNC_redirect,
+
+	/**
+	 * bpf_get_route_realm(skb) - retrieve a dst's tclassid
+	 * @skb: pointer to skb
+	 * Return: realm if != 0
+	 */
+	BPF_FUNC_get_route_realm,
+
+	/**
+	 * bpf_perf_event_output(ctx, map, index, data, size) - output perf raw sample
+	 * @ctx: struct pt_regs*
+	 * @map: pointer to perf_event_array map
+	 * @index: index of event in the map
+	 * @data: data on stack to be output as raw data
+	 * @size: size of data
+	 * Return: 0 on success
+	 */
+	BPF_FUNC_perf_event_output,
+	BPF_FUNC_skb_load_bytes,
+
+	/**
+	 * bpf_get_stackid(ctx, map, flags) - walk user or kernel stack and return id
+	 * @ctx: struct pt_regs*
+	 * @map: pointer to stack_trace map
+	 * @flags: bits 0-7 - numer of stack frames to skip
+	 *         bit 8 - collect user stack instead of kernel
+	 *         bit 9 - compare stacks by hash only
+	 *         bit 10 - if two different stacks hash into the same stackid
+	 *                  discard old
+	 *         other bits - reserved
+	 * Return: >= 0 stackid on success or negative error
+	 */
+	BPF_FUNC_get_stackid,
+
+	/**
+	 * bpf_csum_diff(from, from_size, to, to_size, seed) - calculate csum diff
+	 * @from: raw from buffer
+	 * @from_size: length of from buffer
+	 * @to: raw to buffer
+	 * @to_size: length of to buffer
+	 * @seed: optional seed
+	 * Return: csum result
+	 */
+	BPF_FUNC_csum_diff,
+
+	/**
+	 * bpf_skb_[gs]et_tunnel_opt(skb, opt, size)
+	 * retrieve or populate tunnel options metadata
+	 * @skb: pointer to skb
+	 * @opt: pointer to raw tunnel option data
+	 * @size: size of @opt
+	 * Return: 0 on success for set, option size for get
+	 */
+	BPF_FUNC_skb_get_tunnel_opt,
+	BPF_FUNC_skb_set_tunnel_opt,
+	__BPF_FUNC_MAX_ID,
+};
+
+/* All flags used by eBPF helper functions, placed here. */
+
+/* BPF_FUNC_skb_store_bytes flags. */
+#define BPF_F_RECOMPUTE_CSUM		(1ULL << 0)
+#define BPF_F_INVALIDATE_HASH		(1ULL << 1)
+
+/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
+ * First 4 bits are for passing the header field size.
+ */
+#define BPF_F_HDR_FIELD_MASK		0xfULL
+
+/* BPF_FUNC_l4_csum_replace flags. */
+#define BPF_F_PSEUDO_HDR		(1ULL << 4)
+#define BPF_F_MARK_MANGLED_0		(1ULL << 5)
+
+/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
+#define BPF_F_INGRESS			(1ULL << 0)
+
+/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
+#define BPF_F_TUNINFO_IPV6		(1ULL << 0)
+
+/* BPF_FUNC_get_stackid flags. */
+#define BPF_F_SKIP_FIELD_MASK		0xffULL
+#define BPF_F_USER_STACK		(1ULL << 8)
+#define BPF_F_FAST_STACK_CMP		(1ULL << 9)
+#define BPF_F_REUSE_STACKID		(1ULL << 10)
+
+/* BPF_FUNC_skb_set_tunnel_key flags. */
+#define BPF_F_ZERO_CSUM_TX		(1ULL << 1)
+#define BPF_F_DONT_FRAGMENT		(1ULL << 2)
+
+/* user accessible mirror of in-kernel sk_buff.
+ * new fields can only be added to the end of this structure
+ */
+struct __sk_buff {
+	__u32 len;
+	__u32 pkt_type;
+	__u32 mark;
+	__u32 queue_mapping;
+	__u32 protocol;
+	__u32 vlan_present;
+	__u32 vlan_tci;
+	__u32 vlan_proto;
+	__u32 priority;
+	__u32 ingress_ifindex;
+	__u32 ifindex;
+	__u32 tc_index;
+	__u32 cb[5];
+	__u32 hash;
+	__u32 tc_classid;
+};
+
+struct bpf_tunnel_key {
+	__u32 tunnel_id;
+	union {
+		__u32 remote_ipv4;
+		__u32 remote_ipv6[4];
+	};
+	__u8 tunnel_tos;
+	__u8 tunnel_ttl;
+	__u16 tunnel_ext;
+	__u32 tunnel_label;
+};
+
+#endif /* _UAPI__LINUX_BPF_H__ */
+)********"

src/cc/export/helpers.h

@@ -142,7 +142,6 @@ static u32 (*bpf_get_prandom_u32)(void) =
 static int (*bpf_trace_printk_)(const char *fmt, u64 fmt_size, ...) =
   (void *) BPF_FUNC_trace_printk;
 int bpf_trace_printk(const char *fmt, ...) asm("llvm.bpf.extra");
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0)
 static void bpf_tail_call_(u64 map_fd, void *ctx, int index) {
   ((void (*)(void *, u64, int))BPF_FUNC_tail_call)(ctx, map_fd, index);
 }
@@ -156,8 +155,6 @@ static u64 (*bpf_get_current_uid_gid)(void) =
   (void *) BPF_FUNC_get_current_uid_gid;
 static int (*bpf_get_current_comm)(void *buf, int buf_size) =
   (void *) BPF_FUNC_get_current_comm;
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,3,0)
 static u64 (*bpf_get_cgroup_classid)(void *ctx) =
   (void *) BPF_FUNC_get_cgroup_classid;
 static u64 (*bpf_skb_vlan_push)(void *ctx, u16 proto, u16 vlan_tci) =
@@ -170,20 +167,14 @@ static int (*bpf_skb_set_tunnel_key)(void *ctx, void *from, u32 size, u64 flags)
   (void *) BPF_FUNC_skb_set_tunnel_key;
 static int (*bpf_perf_event_read)(void *map, u32 index) =
   (void *) BPF_FUNC_perf_event_read;
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,0)
 static int (*bpf_redirect)(int ifindex, u32 flags) =
   (void *) BPF_FUNC_redirect;
 static u32 (*bpf_get_route_realm)(void *ctx) =
   (void *) BPF_FUNC_get_route_realm;
 static int (*bpf_perf_event_output)(void *ctx, void *map, u32 index, void *data, u32 size) =
   (void *) BPF_FUNC_perf_event_output;
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,5,0)
 static int (*bpf_skb_load_bytes)(void *ctx, int offset, void *to, u32 len) =
   (void *) BPF_FUNC_skb_load_bytes;
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0)
 static int (*bpf_get_stackid_)(void *ctx, void *map, u64 flags) =
   (void *) BPF_FUNC_get_stackid;
 static inline __attribute__((always_inline))
@@ -192,7 +183,6 @@ int bpf_get_stackid(uintptr_t map, void *ctx, u64 flags) {
 }
 static int (*bpf_csum_diff)(void *from, u64 from_size, void *to, u64 to_size, u64 seed) =
   (void *) BPF_FUNC_csum_diff;
-#endif
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

src/cc/exported_files.cc

@@ -25,6 +25,10 @@ namespace ebpf {
 // see http://www.stroustrup.com/C++11FAQ.html#raw-strings
 
 map<string, const char *> ExportedFiles::headers_ = {
+  {
+    "/virtual/include/bcc/bpf.h",
+    #include "compat/linux/virtual_bpf.h"
+  },
   {
     "/virtual/include/bcc/proto.h",
     #include "export/proto.h"

src/cc/frontends/clang/b_frontend_action.cc

@@ -585,17 +585,14 @@ bool BTypeVisitor::VisitVarDecl(VarDecl *Decl) {
         diag_.Report(Decl->getLocStart(), diag_id) << table.leaf_desc;
       }
     } else if (A->getName() == "maps/prog") {
-      if (KERNEL_VERSION(major,minor,0) >= KERNEL_VERSION(4,2,0))
       map_type = BPF_MAP_TYPE_PROG_ARRAY;
     } else if (A->getName() == "maps/perf_output") {
-      if (KERNEL_VERSION(major,minor,0) >= KERNEL_VERSION(4,3,0))
       map_type = BPF_MAP_TYPE_PERF_EVENT_ARRAY;
       int numcpu = sysconf(_SC_NPROCESSORS_ONLN);
       if (numcpu <= 0)
         numcpu = 1;
       table.max_entries = numcpu;
     } else if (A->getName() == "maps/perf_array") {
-      if (KERNEL_VERSION(major,minor,0) >= KERNEL_VERSION(4,3,0))
       map_type = BPF_MAP_TYPE_PERF_EVENT_ARRAY;
     } else if (A->getName() == "maps/stacktrace") {
       map_type = BPF_MAP_TYPE_STACK_TRACE;

src/cc/frontends/clang/loader.cc

@@ -77,8 +77,6 @@ int ClangLoader::parse(unique_ptr<llvm::Module> *mod, unique_ptr<vector<TableDes
   using namespace clang;
 
   string main_path = "/virtual/main.c";
-  string proto_path = "/virtual/include/bcc/proto.h";
-  string helpers_path = "/virtual/include/bcc/helpers.h";
   unique_ptr<llvm::MemoryBuffer> main_buf;
   struct utsname un;
   uname(&un);
@@ -110,6 +108,8 @@ int ClangLoader::parse(unique_ptr<llvm::Module> *mod, unique_ptr<vector<TableDes
   if (kbuild_helper.get_flags(un.machine, &kflags))
     return -1;
   kflags.push_back("-include");
+  kflags.push_back("/virtual/include/bcc/bpf.h");
+  kflags.push_back("-include");
   kflags.push_back("/virtual/include/bcc/helpers.h");
   kflags.push_back("-isystem");
   kflags.push_back("/virtual/include");