static u32 sock_filter_convert_ctx_access(enum bpf_access_type type,
					  const struct bpf_insn *si,
					  struct bpf_insn *insn_buf,
					  struct bpf_prog *prog, u32 *target_size)
{
	struct bpf_insn *insn = insn_buf;
	int off;

	switch (si->off) {
	case offsetof(struct bpf_sock, bound_dev_if):
		BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_bound_dev_if) != 4);

		if (type == BPF_WRITE)
			*insn++ = BPF_STX_MEM(BPF_W, si->dst_reg, si->src_reg,
					offsetof(struct sock, sk_bound_dev_if));
		else
			*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
				      offsetof(struct sock, sk_bound_dev_if));
		break;

	case offsetof(struct bpf_sock, mark):
		BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_mark) != 4);

		if (type == BPF_WRITE)
			*insn++ = BPF_STX_MEM(BPF_W, si->dst_reg, si->src_reg,
					offsetof(struct sock, sk_mark));
		else
			*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
				      offsetof(struct sock, sk_mark));
		break;

	case offsetof(struct bpf_sock, priority):
		BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_priority) != 4);

		if (type == BPF_WRITE)
			*insn++ = BPF_STX_MEM(BPF_W, si->dst_reg, si->src_reg,
					offsetof(struct sock, sk_priority));
		else
			*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
				      offsetof(struct sock, sk_priority));
		break;

	case offsetof(struct bpf_sock, family):
		BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_family) != 2);

		*insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->src_reg,
				      offsetof(struct sock, sk_family));
		break;

	case offsetof(struct bpf_sock, type):
		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
				      offsetof(struct sock, __sk_flags_offset));
		*insn++ = BPF_ALU32_IMM(BPF_AND, si->dst_reg, SK_FL_TYPE_MASK);
		*insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg, SK_FL_TYPE_SHIFT);
		break;

	case offsetof(struct bpf_sock, protocol):
		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
				      offsetof(struct sock, __sk_flags_offset));
		*insn++ = BPF_ALU32_IMM(BPF_AND, si->dst_reg, SK_FL_PROTO_MASK);
		*insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg, SK_FL_PROTO_SHIFT);
		break;

	case offsetof(struct bpf_sock, src_ip4):
		*insn++ = BPF_LDX_MEM(
			BPF_SIZE(si->code), si->dst_reg, si->src_reg,
			bpf_target_off(struct sock_common, skc_rcv_saddr,
				       FIELD_SIZEOF(struct sock_common,
						    skc_rcv_saddr),
				       target_size));
		break;

	case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]):
#if IS_ENABLED(CONFIG_IPV6)
		off = si->off;
		off -= offsetof(struct bpf_sock, src_ip6[0]);
		*insn++ = BPF_LDX_MEM(
			BPF_SIZE(si->code), si->dst_reg, si->src_reg,
			bpf_target_off(
				struct sock_common,
				skc_v6_rcv_saddr.s6_addr32[0],
				FIELD_SIZEOF(struct sock_common,
					     skc_v6_rcv_saddr.s6_addr32[0]),
				target_size) + off);
#else
		(void)off;
		*insn++ = BPF_MOV32_IMM(si->dst_reg, 0);
#endif
		break;

	case offsetof(struct bpf_sock, src_port):
		*insn++ = BPF_LDX_MEM(
			BPF_FIELD_SIZEOF(struct sock_common, skc_num),
			si->dst_reg, si->src_reg,
			bpf_target_off(struct sock_common, skc_num,
				       FIELD_SIZEOF(struct sock_common,
						    skc_num),
				       target_size));
		break;
	}

	return insn - insn_buf;
}
Unknown