Function eval_alu

dpdk/lib/bpf/bpf_validate.c:648–718

}

static const char *
eval_alu(struct bpf_verifier *bvf, const struct ebpf_insn *ins)
{
	uint64_t msk;
	uint32_t op;
	size_t opsz, sz;
	const char *err;
	struct bpf_eval_state *st;
	struct bpf_reg_val *rd, rs;

	sz = (BPF_CLASS(ins->code) == BPF_ALU) ?
		sizeof(uint32_t) : sizeof(uint64_t);
	opsz = sz * CHAR_BIT;
	msk = RTE_LEN2MASK(opsz, uint64_t);

	st = bvf->evst;
	rd = st->rv + ins->dst_reg;

	if (BPF_SRC(ins->code) == BPF_X) {
		rs = st->rv[ins->src_reg];
		eval_apply_mask(&rs, msk);
	} else {
		rs = (struct bpf_reg_val){.v = {.size = sz,},};
		eval_fill_imm(&rs, msk, ins->imm);
	}

	eval_apply_mask(rd, msk);

	op = BPF_OP(ins->code);

	/* Allow self-xor as way to zero register */
	if (op == BPF_XOR && BPF_SRC(ins->code) == BPF_X &&
	    ins->src_reg == ins->dst_reg) {
		eval_fill_imm(&rs, UINT64_MAX, 0);
		eval_fill_imm(rd, UINT64_MAX, 0);
	}

	err = eval_defined((op != EBPF_MOV) ? rd : NULL,
			   (op != BPF_NEG) ? &rs : NULL);
	if (err != NULL)
		return err;

	if (op == BPF_ADD)
		eval_add(rd, &rs, msk);
	else if (op == BPF_SUB)
		eval_sub(rd, &rs, msk);
	else if (op == BPF_LSH)
		eval_lsh(rd, &rs, opsz, msk);
	else if (op == BPF_RSH)
		eval_rsh(rd, &rs, opsz, msk);
	else if (op == EBPF_ARSH)
		eval_arsh(rd, &rs, opsz, msk);
	else if (op == BPF_AND)
		eval_and(rd, &rs, opsz, msk);
	else if (op == BPF_OR)
		eval_or(rd, &rs, opsz, msk);
	else if (op == BPF_XOR)
		eval_xor(rd, &rs, opsz, msk);