text: /*
   * Linux Socket Filter - Kernel level socket filtering
   *
   * Based on the design of the Berkeley Packet Filter. The new
   * internal format has been designed by PLUMgrid:
   *
   *	Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
   *
   * Authors:
   *
   *	Jay Schulist <jschlst@samba.org>
   *	Alexei Starovoitov <ast@plumgrid.com>
   *	Daniel Borkmann <dborkman@redhat.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   *
   * Andi Kleen - Fix a few bad bugs and races.
   * Kris Katterjohn - Added many additional checks in bpf_check_classic()
   */
  
  #include <linux/filter.h>
  #include <linux/skbuff.h>
  #include <linux/vmalloc.h>
  #include <linux/random.h>
  #include <linux/moduleloader.h>
  #include <linux/bpf.h>
  #include <linux/frame.h>
  
  #include <asm/unaligned.h>
  
  /* Registers */
  #define BPF_R0	regs[BPF_REG_0]
  #define BPF_R1	regs[BPF_REG_1]
  #define BPF_R2	regs[BPF_REG_2]
  #define BPF_R3	regs[BPF_REG_3]
  #define BPF_R4	regs[BPF_REG_4]
  #define BPF_R5	regs[BPF_REG_5]
  #define BPF_R6	regs[BPF_REG_6]
  #define BPF_R7	regs[BPF_REG_7]
  #define BPF_R8	regs[BPF_REG_8]
  #define BPF_R9	regs[BPF_REG_9]
  #define BPF_R10	regs[BPF_REG_10]
  
  /* Named registers */
  #define DST	regs[insn->dst_reg]
  #define SRC	regs[insn->src_reg]
  #define FP	regs[BPF_REG_FP]
  #define ARG1	regs[BPF_REG_ARG1]
  #define CTX	regs[BPF_REG_CTX]
  #define IMM	insn->imm
  
  /* No hurry in this branch
   *
   * Exported for the bpf jit load helper.
   */
  void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
  {
  	u8 *ptr = NULL;
  
  	if (k >= SKF_NET_OFF)
  		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
  	else if (k >= SKF_LL_OFF)
  		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
  
  	if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
  		return ptr;
  
  	return NULL;
  }
  
  struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
  {
  	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
  			  gfp_extra_flags;
  	struct bpf_prog_aux *aux;
  	struct bpf_prog *fp;
  
  	size = round_up(size, PAGE_SIZE);
  	fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
  	if (fp == NULL)
  		return NULL;
  
  	kmemcheck_annotate_bitfield(fp, meta);
  
  	aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
  	if (aux == NULL) {
  		vfree(fp);
  		return NULL;
  	}
  
  	fp->pages = size / PAGE_SIZE;
  	fp->aux = aux;
  	fp->aux->prog = fp;
  
  	return fp;
  }
  EXPORT_SYMBOL_GPL(bpf_prog_alloc);
  
  struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
  				  gfp_t gfp_extra_flags)
  {
  	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
  			  gfp_extra_flags;
  	struct bpf_prog *fp;
  
  	BUG_ON(fp_old == NULL);
  
  	size = round_up(size, PAGE_SIZE);
  	if (size <= fp_old->pages * PAGE_SIZE)
  		return fp_old;
  
  	fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
  	if (fp != NULL) {
  		kmemcheck_annotate_bitfield(fp, meta);
  
  		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
  		fp->pages = size / PAGE_SIZE;
  		fp->aux->prog = fp;
  
  		/* We keep fp->aux from fp_old around in the new
  		 * reallocated structure.
  		 */
  		fp_old->aux = NULL;
  		__bpf_prog_free(fp_old);
  	}
  
  	return fp;
  }
  
  void __bpf_prog_free(struct bpf_prog *fp)
  {
  	kfree(fp->aux);
  	vfree(fp);
  }
  
  static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
  {
  	return BPF_CLASS(insn->code) == BPF_JMP  &&
  	       /* Call and Exit are both special jumps with no
  		* target inside the BPF instruction image.
  		*/
  	       BPF_OP(insn->code) != BPF_CALL &&
  	       BPF_OP(insn->code) != BPF_EXIT;
  }
  
  static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
  {
  	struct bpf_insn *insn = prog->insnsi;
  	u32 i, insn_cnt = prog->len;
  
  	for (i = 0; i < insn_cnt; i++, insn++) {
  		if (!bpf_is_jmp_and_has_target(insn))
  			continue;
  
  		/* Adjust offset of jmps if we cross boundaries. */
  		if (i < pos && i + insn->off + 1 > pos)
  			insn->off += delta;
  		else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
  			insn->off -= delta;
  	}
  }
  
  struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
  				       const struct bpf_insn *patch, u32 len)
  {
  	u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
  	struct bpf_prog *prog_adj;
  
  	/* Since our patchlet doesn't expand the image, we're done. */
  	if (insn_delta == 0) {
  		memcpy(prog->insnsi + off, patch, sizeof(*patch));
  		return prog;
  	}
  
  	insn_adj_cnt = prog->len + insn_delta;
  
  	/* Several new instructions need to be inserted. Make room
  	 * for them. Likely, there's no need for a new allocation as
  	 * last page could have large enough tailroom.
  	 */
  	prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
  				    GFP_USER);
  	if (!prog_adj)
  		return NULL;
  
  	prog_adj->len = insn_adj_cnt;
  
  	/* Patching happens in 3 steps:
  	 *
  	 * 1) Move over tail of insnsi from next instruction onwards,
  	 *    so we can patch the single target insn with one or more
  	 *    new ones (patching is always from 1 to n insns, n > 0).
  	 * 2) Inject new instructions at the target location.
  	 * 3) Adjust branch offsets if necessary.
  	 */
  	insn_rest = insn_adj_cnt - off - len;
  
  	memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
  		sizeof(*patch) * insn_rest);
  	memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
  
  	bpf_adj_branches(prog_adj, off, insn_delta);
  
  	return prog_adj;
  }
  
  #ifdef CONFIG_BPF_JIT
  struct bpf_binary_header *
  bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
  		     unsigned int alignment,
  		     bpf_jit_fill_hole_t bpf_fill_ill_insns)
  {
  	struct bpf_binary_header *hdr;
  	unsigned int size, hole, start;
  
  	/* Most of BPF filters are really small, but if some of them
  	 * fill a page, allow at least 128 extra bytes to insert a
  	 * random section of illegal instructions.
  	 */
  	size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
  	hdr = module_alloc(size);
  	if (hdr == NULL)
  		return NULL;
  
  	/* Fill space with illegal/arch-dep instructions. */
  	bpf_fill_ill_insns(hdr, size);
  
  	hdr->pages = size / PAGE_SIZE;
  	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
  		     PAGE_SIZE - sizeof(*hdr));
  	start = (get_random_int() % hole) & ~(alignment - 1);
  
  	/* Leave a random number of instructions before BPF code. */
  	*image_ptr = &hdr->image[start];
  
  	return hdr;
  }
  
  void bpf_jit_binary_free(struct bpf_binary_header *hdr)
  {
  	module_memfree(hdr);
  }
  
  int bpf_jit_harden __read_mostly;
  
  static int bpf_jit_blind_insn(const struct bpf_insn *from,
  			      const struct bpf_insn *aux,
  			      struct bpf_insn *to_buff)
  {
  	struct bpf_insn *to = to_buff;
  	u32 imm_rnd = get_random_int();
  	s16 off;
  
  	BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
  	BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
  
  	if (from->imm == 0 &&
  	    (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
  	     from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
  		*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
  		goto out;
  	}
  
  	switch (from->code) {
  	case BPF_ALU | BPF_ADD | BPF_K:
  	case BPF_ALU | BPF_SUB | BPF_K:
  	case BPF_ALU | BPF_AND | BPF_K:
  	case BPF_ALU | BPF_OR  | BPF_K:
  	case BPF_ALU | BPF_XOR | BPF_K:
  	case BPF_ALU | BPF_MUL | BPF_K:
  	case BPF_ALU | BPF_MOV | BPF_K:
  	case BPF_ALU | BPF_DIV | BPF_K:
  	case BPF_ALU | BPF_MOD | BPF_K:
  		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
  		break;
  
  	case BPF_ALU64 | BPF_ADD | BPF_K:
  	case BPF_ALU64 | BPF_SUB | BPF_K:
  	case BPF_ALU64 | BPF_AND | BPF_K:
  	case BPF_ALU64 | BPF_OR  | BPF_K:
  	case BPF_ALU64 | BPF_XOR | BPF_K:
  	case BPF_ALU64 | BPF_MUL | BPF_K:
  	case BPF_ALU64 | BPF_MOV | BPF_K:
  	case BPF_ALU64 | BPF_DIV | BPF_K:
  	case BPF_ALU64 | BPF_MOD | BPF_K:
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
  		break;
  
  	case BPF_JMP | BPF_JEQ  | BPF_K:
  	case BPF_JMP | BPF_JNE  | BPF_K:
  	case BPF_JMP | BPF_JGT  | BPF_K:
  	case BPF_JMP | BPF_JGE  | BPF_K:
  	case BPF_JMP | BPF_JSGT | BPF_K:
  	case BPF_JMP | BPF_JSGE | BPF_K:
  	case BPF_JMP | BPF_JSET | BPF_K:
  		/* Accommodate for extra offset in case of a backjump. */
  		off = from->off;
  		if (off < 0)
  			off -= 2;
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
  		break;
  
  	case BPF_LD | BPF_ABS | BPF_W:
  	case BPF_LD | BPF_ABS | BPF_H:
  	case BPF_LD | BPF_ABS | BPF_B:
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
  		break;
  
  	case BPF_LD | BPF_IND | BPF_W:
  	case BPF_LD | BPF_IND | BPF_H:
  	case BPF_LD | BPF_IND | BPF_B:
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
  		*to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
  		break;
  
  	case BPF_LD | BPF_IMM | BPF_DW:
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
  		*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
  		break;
  	case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
  		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
  		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
  		break;
  
  	case BPF_ST | BPF_MEM | BPF_DW:
  	case BPF_ST | BPF_MEM | BPF_W:
  	case BPF_ST | BPF_MEM | BPF_H:
  	case BPF_ST | BPF_MEM | BPF_B:
  		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
  		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
  		*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
  		break;
  	}
  out:
  	return to - to_buff;
  }
  
  static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
  					      gfp_t gfp_extra_flags)
  {
  	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
  			  gfp_extra_flags;
  	struct bpf_prog *fp;
  
  	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
  	if (fp != NULL) {
  		kmemcheck_annotate_bitfield(fp, meta);
  
  		/* aux->prog still points to the fp_other one, so
  		 * when promoting the clone to the real program,
  		 * this still needs to be adapted.
  		 */
  		memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
  	}
  
  	return fp;
  }
  
  static void bpf_prog_clone_free(struct bpf_prog *fp)
  {
  	/* aux was stolen by the other clone, so we cannot free
  	 * it from this path! It will be freed eventually by the
  	 * other program on release.
  	 *
  	 * At this point, we don't need a deferred release since
  	 * clone is guaranteed to not be locked.
  	 */
  	fp->aux = NULL;
  	__bpf_prog_free(fp);
  }
  
  void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
  {
  	/* We have to repoint aux->prog to self, as we don't
  	 * know whether fp here is the clone or the original.
  	 */
  	fp->aux->prog = fp;
  	bpf_prog_clone_free(fp_other);
  }
  
  struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
  {
  	struct bpf_insn insn_buff[16], aux[2];
  	struct bpf_prog *clone, *tmp;
  	int insn_delta, insn_cnt;
  	struct bpf_insn *insn;
  	int i, rewritten;
  
  	if (!bpf_jit_blinding_enabled())
  		return prog;
  
  	clone = bpf_prog_clone_create(prog, GFP_USER);
  	if (!clone)
  		return ERR_PTR(-ENOMEM);
  
  	insn_cnt = clone->len;
  	insn = clone->insnsi;
  
  	for (i = 0; i < insn_cnt; i++, insn++) {
  		/* We temporarily need to hold the original ld64 insn
  		 * so that we can still access the first part in the
  		 * second blinding run.
  		 */
  		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
  		    insn[1].code == 0)
  			memcpy(aux, insn, sizeof(aux));
  
  		rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
  		if (!rewritten)
  			continue;
  
  		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
  		if (!tmp) {
  			/* Patching may have repointed aux->prog during
  			 * realloc from the original one, so we need to
  			 * fix it up here on error.
  			 */
  			bpf_jit_prog_release_other(prog, clone);
  			return ERR_PTR(-ENOMEM);
  		}
  
  		clone = tmp;
  		insn_delta = rewritten - 1;
  
  		/* Walk new program and skip insns we just inserted. */
  		insn = clone->insnsi + i + insn_delta;
  		insn_cnt += insn_delta;
  		i        += insn_delta;
  	}
  
  	return clone;
  }
  #endif /* CONFIG_BPF_JIT */
  
  /* Base function for offset calculation. Needs to go into .text section,
   * therefore keeping it non-static as well; will also be used by JITs
   * anyway later on, so do not let the compiler omit it.
   */
  noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
  {
  	return 0;
  }
  EXPORT_SYMBOL_GPL(__bpf_call_base);
  
  #ifndef CONFIG_BPF_JIT_ALWAYS_ON
  /**
   *	__bpf_prog_run - run eBPF program on a given context
   *	@ctx: is the data we are operating on
   *	@insn: is the array of eBPF instructions
   *
   * Decode and execute eBPF instructions.
   */
  static unsigned int __bpf_prog_run(const struct sk_buff *ctx, const struct bpf_insn *insn)
  {
  	u64 stack[MAX_BPF_STACK / sizeof(u64)];
  	u64 regs[MAX_BPF_REG], tmp;
  	static const void *jumptable[256] = {
  		[0 ... 255] = &&default_label,
  		/* Now overwrite non-defaults ... */
  		/* 32 bit ALU operations */
  		[BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
  		[BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
  		[BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
  		[BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
  		[BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
  		[BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
  		[BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
  		[BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
  		[BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
  		[BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
  		[BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
  		[BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
  		[BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
  		[BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
  		[BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
  		[BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
  		[BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
  		[BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
  		[BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
  		[BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
  		[BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
  		[BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
  		[BPF_ALU | BPF_NEG] = &&ALU_NEG,
  		[BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
  		[BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
  		/* 64 bit ALU operations */
  		[BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
  		[BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
  		[BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
  		[BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
  		[BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
  		[BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
  		[BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
  		[BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
  		[BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
  		[BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
  		[BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
  		[BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
  		[BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
  		[BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
  		[BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
  		[BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
  		[BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
  		[BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
  		[BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
  		[BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
  		[BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
  		[BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
  		[BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
  		[BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
  		[BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
  		/* Call instruction */
  		[BPF_JMP | BPF_CALL] = &&JMP_CALL,
  		[BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
  		/* Jumps */
  		[BPF_JMP | BPF_JA] = &&JMP_JA,
  		[BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
  		[BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
  		[BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
  		[BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
  		[BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
  		[BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
  		[BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
  		[BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
  		[BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
  		[BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
  		[BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
  		[BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
  		[BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
  		[BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
  		/* Program return */
  		[BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
  		/* Store instructions */
  		[BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
  		[BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
  		[BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
  		[BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
  		[BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
  		[BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
  		[BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
  		[BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
  		[BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
  		[BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
  		/* Load instructions */
  		[BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
  		[BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
  		[BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
  		[BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
  		[BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
  		[BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
  		[BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
  		[BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
  		[BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
  		[BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
  		[BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
  	};
  	u32 tail_call_cnt = 0;
  	void *ptr;
  	int off;
  
  #define CONT	 ({ insn++; goto select_insn; })
  #define CONT_JMP ({ insn++; goto select_insn; })
  
  	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
  	ARG1 = (u64) (unsigned long) ctx;
  
  select_insn:
  	goto *jumptable[insn->code];
  
  	/* ALU */
  #define ALU(OPCODE, OP)			\
  	ALU64_##OPCODE##_X:		\
  		DST = DST OP SRC;	\
  		CONT;			\
  	ALU_##OPCODE##_X:		\
  		DST = (u32) DST OP (u32) SRC;	\
  		CONT;			\
  	ALU64_##OPCODE##_K:		\
  		DST = DST OP IMM;		\
  		CONT;			\
  	ALU_##OPCODE##_K:		\
  		DST = (u32) DST OP (u32) IMM;	\
  		CONT;
  
  	ALU(ADD,  +)
  	ALU(SUB,  -)
  	ALU(AND,  &)
  	ALU(OR,   |)
  	ALU(LSH, <<)
  	ALU(RSH, >>)
  	ALU(XOR,  ^)
  	ALU(MUL,  *)
  #undef ALU
  	ALU_NEG:
  		DST = (u32) -DST;
  		CONT;
  	ALU64_NEG:
  		DST = -DST;
  		CONT;
  	ALU_MOV_X:
  		DST = (u32) SRC;
  		CONT;
  	ALU_MOV_K:
  		DST = (u32) IMM;
  		CONT;
  	ALU64_MOV_X:
  		DST = SRC;
  		CONT;
  	ALU64_MOV_K:
  		DST = IMM;
  		CONT;
  	LD_IMM_DW:
  		DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
  		insn++;
  		CONT;
  	ALU64_ARSH_X:
  		(*(s64 *) &DST) >>= SRC;
  		CONT;
  	ALU64_ARSH_K:
  		(*(s64 *) &DST) >>= IMM;
  		CONT;
  	ALU64_MOD_X:
  		if (unlikely(SRC == 0))
  			return 0;
  		div64_u64_rem(DST, SRC, &tmp);
  		DST = tmp;
  		CONT;
  	ALU_MOD_X:
  		if (unlikely((u32)SRC == 0))
  			return 0;
  		tmp = (u32) DST;
  		DST = do_div(tmp, (u32) SRC);
  		CONT;
  	ALU64_MOD_K:
  		div64_u64_rem(DST, IMM, &tmp);
  		DST = tmp;
  		CONT;
  	ALU_MOD_K:
  		tmp = (u32) DST;
  		DST = do_div(tmp, (u32) IMM);
  		CONT;
  	ALU64_DIV_X:
  		if (unlikely(SRC == 0))
  			return 0;
  		DST = div64_u64(DST, SRC);
  		CONT;
  	ALU_DIV_X:
  		if (unlikely((u32)SRC == 0))
  			return 0;
  		tmp = (u32) DST;
  		do_div(tmp, (u32) SRC);
  		DST = (u32) tmp;
  		CONT;
  	ALU64_DIV_K:
  		DST = div64_u64(DST, IMM);
  		CONT;
  	ALU_DIV_K:
  		tmp = (u32) DST;
  		do_div(tmp, (u32) IMM);
  		DST = (u32) tmp;
  		CONT;
  	ALU_END_TO_BE:
  		switch (IMM) {
  		case 16:
  			DST = (__force u16) cpu_to_be16(DST);
  			break;
  		case 32:
  			DST = (__force u32) cpu_to_be32(DST);
  			break;
  		case 64:
  			DST = (__force u64) cpu_to_be64(DST);
  			break;
  		}
  		CONT;
  	ALU_END_TO_LE:
  		switch (IMM) {
  		case 16:
  			DST = (__force u16) cpu_to_le16(DST);
  			break;
  		case 32:
  			DST = (__force u32) cpu_to_le32(DST);
  			break;
  		case 64:
  			DST = (__force u64) cpu_to_le64(DST);
  			break;
  		}
  		CONT;
  
  	/* CALL */
  	JMP_CALL:
  		/* Function call scratches BPF_R1-BPF_R5 registers,
  		 * preserves BPF_R6-BPF_R9, and stores return value
  		 * into BPF_R0.
  		 */
  		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
  						       BPF_R4, BPF_R5);
  		CONT;
  
  	JMP_TAIL_CALL: {
  		struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
  		struct bpf_array *array = container_of(map, struct bpf_array, map);
  		struct bpf_prog *prog;
  		u32 index = BPF_R3;
  
  		if (unlikely(index >= array->map.max_entries))
  			goto out;
  		if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
  			goto out;
  
  		tail_call_cnt++;
  
  		prog = READ_ONCE(array->ptrs[index]);
  		if (!prog)
  			goto out;
  
  		/* ARG1 at this point is guaranteed to point to CTX from
  		 * the verifier side due to the fact that the tail call is
  		 * handeled like a helper, that is, bpf_tail_call_proto,
  		 * where arg1_type is ARG_PTR_TO_CTX.
  		 */
  		insn = prog->insnsi;
  		goto select_insn;
  out:
  		CONT;
  	}
  	/* JMP */
  	JMP_JA:
  		insn += insn->off;
  		CONT;
  	JMP_JEQ_X:
  		if (DST == SRC) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JEQ_K:
  		if (DST == IMM) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JNE_X:
  		if (DST != SRC) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JNE_K:
  		if (DST != IMM) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JGT_X:
  		if (DST > SRC) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JGT_K:
  		if (DST > IMM) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JGE_X:
  		if (DST >= SRC) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JGE_K:
  		if (DST >= IMM) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSGT_X:
  		if (((s64) DST) > ((s64) SRC)) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSGT_K:
  		if (((s64) DST) > ((s64) IMM)) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSGE_X:
  		if (((s64) DST) >= ((s64) SRC)) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSGE_K:
  		if (((s64) DST) >= ((s64) IMM)) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSET_X:
  		if (DST & SRC) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_JSET_K:
  		if (DST & IMM) {
  			insn += insn->off;
  			CONT_JMP;
  		}
  		CONT;
  	JMP_EXIT:
  		return BPF_R0;
  
  	/* STX and ST and LDX*/
  #define LDST(SIZEOP, SIZE)						\
  	STX_MEM_##SIZEOP:						\
  		*(SIZE *)(unsigned long) (DST + insn->off) = SRC;	\
  		CONT;							\
  	ST_MEM_##SIZEOP:						\
  		*(SIZE *)(unsigned long) (DST + insn->off) = IMM;	\
  		CONT;							\
  	LDX_MEM_##SIZEOP:						\
  		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
  		CONT;
  
  	LDST(B,   u8)
  	LDST(H,  u16)
  	LDST(W,  u32)
  	LDST(DW, u64)
  #undef LDST
  	STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
  		atomic_add((u32) SRC, (atomic_t *)(unsigned long)
  			   (DST + insn->off));
  		CONT;
  	STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
  		atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
  			     (DST + insn->off));
  		CONT;
  	LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
  		off = IMM;
  load_word:
  		/* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
  		 * only appearing in the programs where ctx ==
  		 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
  		 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
  		 * internal BPF verifier will check that BPF_R6 ==
  		 * ctx.
  		 *
  		 * BPF_ABS and BPF_IND are wrappers of function calls,
  		 * so they scratch BPF_R1-BPF_R5 registers, preserve
  		 * BPF_R6-BPF_R9, and store return value into BPF_R0.
  		 *
  		 * Implicit input:
  		 *   ctx == skb == BPF_R6 == CTX
  		 *
  		 * Explicit input:
  		 *   SRC == any register
  		 *   IMM == 32-bit immediate
  		 *
  		 * Output:
  		 *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
  		 */
  
  		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
  		if (likely(ptr != NULL)) {
  			BPF_R0 = get_unaligned_be32(ptr);
  			CONT;
  		}
  
  		return 0;
  	LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
  		off = IMM;
  load_half:
  		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
  		if (likely(ptr != NULL)) {
  			BPF_R0 = get_unaligned_be16(ptr);
  			CONT;
  		}
  
  		return 0;
  	LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
  		off = IMM;
  load_byte:
  		ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
  		if (likely(ptr != NULL)) {
  			BPF_R0 = *(u8 *)ptr;
  			CONT;
  		}
  
  		return 0;
  	LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
  		off = IMM + SRC;
  		goto load_word;
  	LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
  		off = IMM + SRC;
  		goto load_half;
  	LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
  		off = IMM + SRC;
  		goto load_byte;
  
  	default_label:
  		/* If we ever reach this, we have a bug somewhere. */
  		WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
  		return 0;
  }
  STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */
  
  #else
  static unsigned int __bpf_prog_ret0(void *ctx, const struct bpf_insn *insn)
  {
  	return 0;
  }
  #endif
  
  bool bpf_prog_array_compatible(struct bpf_array *array,
  			       const struct bpf_prog *fp)
  {
  	if (!array->owner_prog_type) {
  		/* There's no owner yet where we could check for
  		 * compatibility.
  		 */
  		array->owner_prog_type = fp->type;
  		array->owner_jited = fp->jited;
  
  		return true;
  	}
  
  	return array->owner_prog_type == fp->type &&
  	       array->owner_jited == fp->jited;
  }
  
  static int bpf_check_tail_call(const struct bpf_prog *fp)
  {
  	struct bpf_prog_aux *aux = fp->aux;
  	int i;
  
  	for (i = 0; i < aux->used_map_cnt; i++) {
  		struct bpf_map *map = aux->used_maps[i];
  		struct bpf_array *array;
  
  		if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
  			continue;
  
  		array = container_of(map, struct bpf_array, map);
  		if (!bpf_prog_array_compatible(array, fp))
  			return -EINVAL;
  	}
  
  	return 0;
  }
  
  /**
   *	bpf_prog_select_runtime - select exec runtime for BPF program
   *	@fp: bpf_prog populated with internal BPF program
   *	@err: pointer to error variable
   *
   * Try to JIT eBPF program, if JIT is not available, use interpreter.
   * The BPF program will be executed via BPF_PROG_RUN() macro.
   */
  struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
  {
  #ifndef CONFIG_BPF_JIT_ALWAYS_ON
  	fp->bpf_func = (void *) __bpf_prog_run;
  #else
  	fp->bpf_func = (void *) __bpf_prog_ret0;
  #endif
  
  	/* eBPF JITs can rewrite the program in case constant
  	 * blinding is active. However, in case of error during
  	 * blinding, bpf_int_jit_compile() must always return a
  	 * valid program, which in this case would simply not
  	 * be JITed, but falls back to the interpreter.
  	 */
  	fp = bpf_int_jit_compile(fp);
  #ifdef CONFIG_BPF_JIT_ALWAYS_ON
  	if (!fp->jited) {
  		*err = -ENOTSUPP;
  		return fp;
  	}
  #endif
  	bpf_prog_lock_ro(fp);
  
  	/* The tail call compatibility check can only be done at
  	 * this late stage as we need to determine, if we deal
  	 * with JITed or non JITed program concatenations and not
  	 * all eBPF JITs might immediately support all features.
  	 */
  	*err = bpf_check_tail_call(fp);
  
  	return fp;
  }
  EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
  
  static void bpf_prog_free_deferred(struct work_struct *work)
  {
  	struct bpf_prog_aux *aux;
  
  	aux = container_of(work, struct bpf_prog_aux, work);
  	bpf_jit_free(aux->prog);
  }
  
  /* Free internal BPF program */
  void bpf_prog_free(struct bpf_prog *fp)
  {
  	struct bpf_prog_aux *aux = fp->aux;
  
  	INIT_WORK(&aux->work, bpf_prog_free_deferred);
  	schedule_work(&aux->work);
  }
  EXPORT_SYMBOL_GPL(bpf_prog_free);
  
  /* RNG for unpriviledged user space with separated state from prandom_u32(). */
  static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
  
  void bpf_user_rnd_init_once(void)
  {
  	prandom_init_once(&bpf_user_rnd_state);
  }
  
  BPF_CALL_0(bpf_user_rnd_u32)
  {
  	/* Should someone ever have the rather unwise idea to use some
  	 * of the registers passed into this function, then note that
  	 * this function is called from native eBPF and classic-to-eBPF
  	 * transformations. Register assignments from both sides are
  	 * different, f.e. classic always sets fn(ctx, A, X) here.
  	 */
  	struct rnd_state *state;
  	u32 res;
  
  	state = &get_cpu_var(bpf_user_rnd_state);
  	res = prandom_u32_state(state);
  	put_cpu_var(bpf_user_rnd_state);
  
  	return res;
  }
  
  /* Weak definitions of helper functions in case we don't have bpf syscall. */
  const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
  const struct bpf_func_proto bpf_map_update_elem_proto __weak;
  const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
  
  const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
  const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
  const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
  
  const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
  const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
  const struct bpf_func_proto bpf_get_current_comm_proto __weak;
  
  const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
  {
  	return NULL;
  }
  
  u64 __weak
  bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
  		 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
  {
  	return -ENOTSUPP;
  }
  
  /* Always built-in helper functions. */
  const struct bpf_func_proto bpf_tail_call_proto = {
  	.func		= NULL,
  	.gpl_only	= false,
  	.ret_type	= RET_VOID,
  	.arg1_type	= ARG_PTR_TO_CTX,
  	.arg2_type	= ARG_CONST_MAP_PTR,
  	.arg3_type	= ARG_ANYTHING,
  };
  
  /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
  struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
  {
  	return prog;
  }
  
  bool __weak bpf_helper_changes_skb_data(void *func)
  {
  	return false;
  }
  
  /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
   * skb_copy_bits(), so provide a weak definition of it for NET-less config.
   */
  int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
  			 int len)
  {
  	return -EFAULT;
  }
  