--- /dev/null
+#include <asm/types.h>
+#include <linux/types.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#include <linux/unistd.h>
+#include <linux/filter.h>
+#include <linux/bpf_perf_event.h>
+#include <linux/bpf.h>
+
+#include <bpf/bpf.h>
+
+#include "../../../include/linux/filter.h"
+
+#ifndef ARRAY_SIZE
+# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+#define MAX_INSNS 512
+#define MAX_MATCHES 16
+
+struct bpf_align_test {
+ const char *descr;
+ struct bpf_insn insns[MAX_INSNS];
+ enum {
+ UNDEF,
+ ACCEPT,
+ REJECT
+ } result;
+ enum bpf_prog_type prog_type;
+ const char *matches[MAX_MATCHES];
+};
+
+static struct bpf_align_test tests[] = {
+ {
+ .descr = "mov",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, 2),
+ BPF_MOV64_IMM(BPF_REG_3, 4),
+ BPF_MOV64_IMM(BPF_REG_3, 8),
+ BPF_MOV64_IMM(BPF_REG_3, 16),
+ BPF_MOV64_IMM(BPF_REG_3, 32),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "1: R1=ctx R3=imm2,min_value=2,max_value=2,min_align=2 R10=fp",
+ "2: R1=ctx R3=imm4,min_value=4,max_value=4,min_align=4 R10=fp",
+ "3: R1=ctx R3=imm8,min_value=8,max_value=8,min_align=8 R10=fp",
+ "4: R1=ctx R3=imm16,min_value=16,max_value=16,min_align=16 R10=fp",
+ "5: R1=ctx R3=imm32,min_value=32,max_value=32,min_align=32 R10=fp",
+ },
+ },
+ {
+ .descr = "shift",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_3, 4),
+ BPF_MOV64_IMM(BPF_REG_4, 32),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "1: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R10=fp",
+ "2: R1=ctx R3=imm2,min_value=2,max_value=2,min_align=2 R10=fp",
+ "3: R1=ctx R3=imm4,min_value=4,max_value=4,min_align=4 R10=fp",
+ "4: R1=ctx R3=imm8,min_value=8,max_value=8,min_align=8 R10=fp",
+ "5: R1=ctx R3=imm16,min_value=16,max_value=16,min_align=16 R10=fp",
+ "6: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R10=fp",
+ "7: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R4=imm32,min_value=32,max_value=32,min_align=32 R10=fp",
+ "8: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R4=imm16,min_value=16,max_value=16,min_align=16 R10=fp",
+ "9: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R4=imm8,min_value=8,max_value=8,min_align=8 R10=fp",
+ "10: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R4=imm4,min_value=4,max_value=4,min_align=4 R10=fp",
+ "11: R1=ctx R3=imm1,min_value=1,max_value=1,min_align=1 R4=imm2,min_value=2,max_value=2,min_align=2 R10=fp",
+ },
+ },
+ {
+ .descr = "addsub",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, 4),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 4),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 2),
+ BPF_MOV64_IMM(BPF_REG_4, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "1: R1=ctx R3=imm4,min_value=4,max_value=4,min_align=4 R10=fp",
+ "2: R1=ctx R3=imm8,min_value=8,max_value=8,min_align=4 R10=fp",
+ "3: R1=ctx R3=imm10,min_value=10,max_value=10,min_align=2 R10=fp",
+ "4: R1=ctx R3=imm10,min_value=10,max_value=10,min_align=2 R4=imm8,min_value=8,max_value=8,min_align=8 R10=fp",
+ "5: R1=ctx R3=imm10,min_value=10,max_value=10,min_align=2 R4=imm12,min_value=12,max_value=12,min_align=4 R10=fp",
+ "6: R1=ctx R3=imm10,min_value=10,max_value=10,min_align=2 R4=imm14,min_value=14,max_value=14,min_align=2 R10=fp",
+ },
+ },
+ {
+ .descr = "mul",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, 7),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 2),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 4),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "1: R1=ctx R3=imm7,min_value=7,max_value=7,min_align=1 R10=fp",
+ "2: R1=ctx R3=imm7,min_value=7,max_value=7,min_align=1 R10=fp",
+ "3: R1=ctx R3=imm14,min_value=14,max_value=14,min_align=2 R10=fp",
+ "4: R1=ctx R3=imm56,min_value=56,max_value=56,min_align=4 R10=fp",
+ },
+ },
+
+#define PREP_PKT_POINTERS \
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, \
+ offsetof(struct __sk_buff, data)), \
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, \
+ offsetof(struct __sk_buff, data_end))
+
+#define LOAD_UNKNOWN(DST_REG) \
+ PREP_PKT_POINTERS, \
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), \
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8), \
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_0, 1), \
+ BPF_EXIT_INSN(), \
+ BPF_LDX_MEM(BPF_B, DST_REG, BPF_REG_2, 0)
+
+ {
+ .descr = "unknown shift",
+ .insns = {
+ LOAD_UNKNOWN(BPF_REG_3),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
+ LOAD_UNKNOWN(BPF_REG_4),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_4, 5),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "7: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R10=fp",
+ "8: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv55,min_align=2 R10=fp",
+ "9: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv54,min_align=4 R10=fp",
+ "10: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv53,min_align=8 R10=fp",
+ "11: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv52,min_align=16 R10=fp",
+ "18: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv56 R10=fp",
+ "19: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv51,min_align=32 R10=fp",
+ "20: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv52,min_align=16 R10=fp",
+ "21: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv53,min_align=8 R10=fp",
+ "22: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv54,min_align=4 R10=fp",
+ "23: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv55,min_align=2 R10=fp",
+ },
+ },
+ {
+ .descr = "unknown mul",
+ .insns = {
+ LOAD_UNKNOWN(BPF_REG_3),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 1),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 4),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 8),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "7: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R10=fp",
+ "8: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv56 R10=fp",
+ "9: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv55,min_align=1 R10=fp",
+ "10: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv56 R10=fp",
+ "11: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv54,min_align=2 R10=fp",
+ "12: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv56 R10=fp",
+ "13: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv53,min_align=4 R10=fp",
+ "14: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv56 R10=fp",
+ "15: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv52,min_align=8 R10=fp",
+ "16: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=inv56 R4=inv50,min_align=8 R10=fp"
+ },
+ },
+ {
+ .descr = "packet const offset",
+ .insns = {
+ PREP_PKT_POINTERS,
+ BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
+
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+
+ /* Skip over ethernet header. */
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+
+ BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 0),
+ BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 1),
+ BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 2),
+ BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 3),
+ BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 0),
+ BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 2),
+ BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
+
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ "4: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R5=pkt(id=0,off=0,r=0) R10=fp",
+ "5: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R5=pkt(id=0,off=14,r=0) R10=fp",
+ "6: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R4=pkt(id=0,off=14,r=0) R5=pkt(id=0,off=14,r=0) R10=fp",
+ "10: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=18) R3=pkt_end R4=inv56 R5=pkt(id=0,off=14,r=18) R10=fp",
+ "14: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=18) R3=pkt_end R4=inv48 R5=pkt(id=0,off=14,r=18) R10=fp",
+ "15: R0=imm0,min_value=0,max_value=0,min_align=2147483648 R1=ctx R2=pkt(id=0,off=0,r=18) R3=pkt_end R4=inv48 R5=pkt(id=0,off=14,r=18) R10=fp",
+ },
+ },
+ {
+ .descr = "packet variable offset",
+ .insns = {
+ LOAD_UNKNOWN(BPF_REG_6),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
+
+ /* First, add a constant to the R5 packet pointer,
+ * then a variable with a known alignment.
+ */
+ BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
+
+ /* Now, test in the other direction. Adding first
+ * the variable offset to R5, then the constant.
+ */
+ BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
+
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ /* Calculated offset in R6 has unknown value, but known
+ * alignment of 4.
+ */
+ "8: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R6=inv54,min_align=4 R10=fp",
+
+ /* Offset is added to packet pointer R5, resulting in known
+ * auxiliary alignment and offset.
+ */
+ "11: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R5=pkt(id=1,off=0,r=0),aux_off=14,aux_off_align=4 R6=inv54,min_align=4 R10=fp",
+
+ /* At the time the word size load is performed from R5,
+ * it's total offset is NET_IP_ALIGN + reg->off (0) +
+ * reg->aux_off (14) which is 16. Then the variable
+ * offset is considered using reg->aux_off_align which
+ * is 4 and meets the load's requirements.
+ */
+ "15: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=pkt(id=1,off=4,r=4),aux_off=14,aux_off_align=4 R5=pkt(id=1,off=0,r=4),aux_off=14,aux_off_align=4 R6=inv54,min_align=4 R10=fp",
+
+
+ /* Variable offset is added to R5 packet pointer,
+ * resulting in auxiliary alignment of 4.
+ */
+ "18: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv,aux_off=14,aux_off_align=4 R5=pkt(id=2,off=0,r=0),aux_off_align=4 R6=inv54,min_align=4 R10=fp",
+
+ /* Constant offset is added to R5, resulting in
+ * reg->off of 14.
+ */
+ "19: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=inv,aux_off=14,aux_off_align=4 R5=pkt(id=2,off=14,r=0),aux_off_align=4 R6=inv54,min_align=4 R10=fp",
+
+ /* At the time the word size load is performed from R5,
+ * it's total offset is NET_IP_ALIGN + reg->off (14) which
+ * is 16. Then the variable offset is considered using
+ * reg->aux_off_align which is 4 and meets the load's
+ * requirements.
+ */
+ "23: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R4=pkt(id=2,off=18,r=18),aux_off_align=4 R5=pkt(id=2,off=14,r=18),aux_off_align=4 R6=inv54,min_align=4 R10=fp",
+ },
+ },
+};
+
+static int probe_filter_length(const struct bpf_insn *fp)
+{
+ int len;
+
+ for (len = MAX_INSNS - 1; len > 0; --len)
+ if (fp[len].code != 0 || fp[len].imm != 0)
+ break;
+ return len + 1;
+}
+
+static char bpf_vlog[32768];
+
+static int do_test_single(struct bpf_align_test *test)
+{
+ struct bpf_insn *prog = test->insns;
+ int prog_type = test->prog_type;
+ int prog_len, i;
+ int fd_prog;
+ int ret;
+
+ prog_len = probe_filter_length(prog);
+ fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
+ prog, prog_len, 1, "GPL", 0,
+ bpf_vlog, sizeof(bpf_vlog));
+ if (fd_prog < 0) {
+ printf("Failed to load program.\n");
+ printf("%s", bpf_vlog);
+ ret = 1;
+ } else {
+ ret = 0;
+ for (i = 0; i < MAX_MATCHES; i++) {
+ const char *t, *m = test->matches[i];
+
+ if (!m)
+ break;
+ t = strstr(bpf_vlog, m);
+ if (!t) {
+ printf("Failed to find match: %s\n", m);
+ ret = 1;
+ printf("%s", bpf_vlog);
+ break;
+ }
+ }
+ /* printf("%s", bpf_vlog); */
+ close(fd_prog);
+ }
+ return ret;
+}
+
+static int do_test(unsigned int from, unsigned int to)
+{
+ int all_pass = 0;
+ int all_fail = 0;
+ unsigned int i;
+
+ for (i = from; i < to; i++) {
+ struct bpf_align_test *test = &tests[i];
+ int fail;
+
+ printf("Test %3d: %s ... ",
+ i, test->descr);
+ fail = do_test_single(test);
+ if (fail) {
+ all_fail++;
+ printf("FAIL\n");
+ } else {
+ all_pass++;
+ printf("PASS\n");
+ }
+ }
+ printf("Results: %d pass %d fail\n",
+ all_pass, all_fail);
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ unsigned int from = 0, to = ARRAY_SIZE(tests);
+
+ if (argc == 3) {
+ unsigned int l = atoi(argv[argc - 2]);
+ unsigned int u = atoi(argv[argc - 1]);
+
+ if (l < to && u < to) {
+ from = l;
+ to = u + 1;
+ }
+ } else if (argc == 2) {
+ unsigned int t = atoi(argv[argc - 1]);
+
+ if (t < to) {
+ from = t;
+ to = t + 1;
+ }
+ }
+ return do_test(from, to);
+}