bpf: expose internal verfier structures

Move verifier's internal structures to a header file and
prefix their names with bpf_ to avoid potential namespace
conflicts.  Those structures will soon be used by external
analyzers.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/bpf_verifier.h

+/* 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 _LINUX_BPF_VERIFIER_H
+#define _LINUX_BPF_VERIFIER_H 1
+
+#include <linux/bpf.h> /* for enum bpf_reg_type */
+#include <linux/filter.h> /* for MAX_BPF_STACK */
+
+struct bpf_reg_state {
+	enum bpf_reg_type type;
+	union {
+		/* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */
+		s64 imm;
+
+		/* valid when type == PTR_TO_PACKET* */
+		struct {
+			u32 id;
+			u16 off;
+			u16 range;
+		};
+
+		/* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
+		 *   PTR_TO_MAP_VALUE_OR_NULL
+		 */
+		struct bpf_map *map_ptr;
+	};
+};
+
+enum bpf_stack_slot_type {
+	STACK_INVALID,    /* nothing was stored in this stack slot */
+	STACK_SPILL,      /* register spilled into stack */
+	STACK_MISC	  /* BPF program wrote some data into this slot */
+};
+
+#define BPF_REG_SIZE 8	/* size of eBPF register in bytes */
+
+/* state of the program:
+ * type of all registers and stack info
+ */
+struct bpf_verifier_state {
+	struct bpf_reg_state regs[MAX_BPF_REG];
+	u8 stack_slot_type[MAX_BPF_STACK];
+	struct bpf_reg_state spilled_regs[MAX_BPF_STACK / BPF_REG_SIZE];
+};
+
+/* linked list of verifier states used to prune search */
+struct bpf_verifier_state_list {
+	struct bpf_verifier_state state;
+	struct bpf_verifier_state_list *next;
+};
+
+struct bpf_insn_aux_data {
+	enum bpf_reg_type ptr_type;	/* pointer type for load/store insns */
+};
+
+#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
+
+/* single container for all structs
+ * one verifier_env per bpf_check() call
+ */
+struct bpf_verifier_env {
+	struct bpf_prog *prog;		/* eBPF program being verified */
+	struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
+	int stack_size;			/* number of states to be processed */
+	struct bpf_verifier_state cur_state; /* current verifier state */
+	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
+	struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
+	u32 used_map_cnt;		/* number of used maps */
+	u32 id_gen;			/* used to generate unique reg IDs */
+	bool allow_ptr_leaks;
+	bool seen_direct_write;
+	struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
+};
+
+#endif /* _LINUX_BPF_VERIFIER_H */