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in-addr-util: reimplement in_addr_prefix_range()

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Currently, in_addr_prefix_range() is the only user of in_addr_prefix_nth(),
and it is too generic and complicated.
Previously, in_addr_prefix_range() calls in_addr_prefix_nth() with 0 and 1.
The function in_addr_prefix_nth(0) is equivalent to in_addr_mask(), and
in_addr_prefix_nth(1) is equivalent to just increment the masked value
with 1.
So, let's reimplement the code without using in_addr_prefix_nth().
This commit is contained in:
Yu Watanabe
2026-09-23 13:53:23 +09:00
parent b4d5d083fd
commit be21269a68
2 changed files with 106 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/in-addr-util.c
+35 -13
View File
@@ -426,28 +426,50 @@ int in_addr_prefix_range(
union in_addr_union *ret_start,
union in_addr_union *ret_end) {
union in_addr_union start, end;
int r;
assert(in);
if (!IN_SET(family, AF_INET, AF_INET6))
/* Note, on overflow, e.g. input is 255.255.255.255, then ret_end will be a null address. */
switch (family) {
case AF_INET:
if (prefixlen > 32)
return -EINVAL;
break;
case AF_INET6:
if (prefixlen > 128)
return -EINVAL;
break;
default:
return -EAFNOSUPPORT;
if (ret_start) {
start = *in;
r = in_addr_prefix_nth(family, &start, prefixlen, 0);
if (r < 0)
return r;
}
if (ret_end) {
end = *in;
r = in_addr_prefix_nth(family, &end, prefixlen, 1);
if (r < 0)
return r;
if (prefixlen == 0) {
/* shortcut for trivial case */
if (ret_start)
*ret_start = IN_ADDR_NULL;
if (ret_end)
*ret_end = IN_ADDR_NULL;
return 0;
}
union in_addr_union start = *in;
r = in_addr_mask(family, &start, prefixlen);
if (r < 0)
return r;
union in_addr_union end = start;
uint8_t add = UINT8_C(1) << ((FAMILY_ADDRESS_SIZE(family) * 8 - prefixlen) % 8);
for (unsigned i = DIV_ROUND_UP(prefixlen, 8); i-- > 0;)
if (add > UINT8_MAX - end.bytes[i]) {
end.bytes[i] = 0;
add = 1;
} else {
end.bytes[i] += add;
break;
}
if (ret_start)
*ret_start = start;
if (ret_end)
src/test/test-in-addr-util.c
+71 -15
View File
@@ -261,38 +261,94 @@ static void test_in_addr_prefix_range_one(
const char *expected_start,
const char *expected_end) {
union in_addr_union a, s, e;
assert(!expected_start == !expected_end);
log_debug("/* %s(%s, prefixlen=%u) */", __func__, in, prefixlen);
assert_se(in_addr_from_string(family, in, &a) >= 0);
assert_se((in_addr_prefix_range(family, &a, prefixlen, &s, &e) >= 0) == !!expected_start);
union in_addr_union a, s, e;
ASSERT_OK(in_addr_from_string(family, in, &a));
if (expected_start) {
union in_addr_union es;
assert_se(in_addr_from_string(family, expected_start, &es) >= 0);
assert_se(in_addr_equal(family, &s, &es) > 0);
if (!expected_start) {
ASSERT_ERROR(in_addr_prefix_range(family, &a, prefixlen, NULL, NULL), EINVAL);
ASSERT_ERROR(in_addr_prefix_range(family, &a, prefixlen, &s, NULL), EINVAL);
ASSERT_ERROR(in_addr_prefix_range(family, &a, prefixlen, NULL, &e), EINVAL);
ASSERT_ERROR(in_addr_prefix_range(family, &a, prefixlen, &s, &e), EINVAL);
return;
}
if (expected_end) {
union in_addr_union ee;
assert_se(in_addr_from_string(family, expected_end, &ee) >= 0);
assert_se(in_addr_equal(family, &e, &ee) > 0);
}
ASSERT_OK(in_addr_prefix_range(family, &a, prefixlen, NULL, NULL));
ASSERT_OK(in_addr_prefix_range(family, &a, prefixlen, &s, NULL));
ASSERT_OK(in_addr_prefix_range(family, &a, prefixlen, NULL, &e));
ASSERT_OK(in_addr_prefix_range(family, &a, prefixlen, &s, &e));
union in_addr_union es;
ASSERT_OK(in_addr_from_string(family, expected_start, &es));
ASSERT_OK_POSITIVE(in_addr_equal(family, &s, &es));
union in_addr_union ee;
ASSERT_OK(in_addr_from_string(family, expected_end, &ee));
ASSERT_OK_POSITIVE(in_addr_equal(family, &e, &ee));
}
TEST(in_addr_prefix_range) {
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 24, "192.168.123.0", "192.168.124.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 0, "0.0.0.0", "0.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 1, "128.0.0.0", "0.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 2, "192.0.0.0", "0.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 3, "192.0.0.0", "224.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 4, "192.0.0.0", "208.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 5, "192.0.0.0", "200.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 6, "192.0.0.0", "196.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 7, "192.0.0.0", "194.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 8, "192.0.0.0", "193.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 9, "192.128.0.0", "193.0.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 10, "192.128.0.0", "192.192.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 16, "192.168.0.0", "192.169.0.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 24, "192.168.123.0", "192.168.124.0");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 32, "192.168.123.123", "192.168.123.124");
test_in_addr_prefix_range_one(AF_INET, "192.168.123.123", 33, NULL, NULL);
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 0, "::", "::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 1, "8000::", "::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 2, "c000::", "::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 3, "c000::", "e000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 4, "d000::", "e000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 7, "de00::", "e000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 8, "de00::", "df00::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 9, "de80::", "df00::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 16, "dead:0000::", "deae:0000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 17, "dead:8000::", "deae:0000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 18, "dead:8000::", "dead:c000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 19, "dead:a000::", "dead:c000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 20, "dead:b000::", "dead:c000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 21, "dead:b800::", "dead:c000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 28, "dead:bee0::", "dead:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 29, "dead:bee8::", "dead:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 30, "dead:beec::", "dead:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 31, "dead:beee::", "dead:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 32, "dead:beef::", "dead:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 33, "dead:beef::", "dead:beef:8000::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 64, "dead:beef::", "dead:beef:0:1::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 128, "dead:beef::", "dead:beef::1");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 129, NULL, NULL);
test_in_addr_prefix_range_one(AF_INET6, "dead:beef::", 64, "dead:beef::", "dead:beef:0:1::");
test_in_addr_prefix_range_one(AF_INET6, "dead:0:0:beef::", 64, "dead:0:0:beef::", "dead:0:0:bef0::");
test_in_addr_prefix_range_one(AF_INET6, "dead:beef:0:ffff::", 64, "dead:beef:0:ffff::", "dead:beef:1::");
test_in_addr_prefix_range_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 128, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 0, "::", "::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 1, "::", "8000::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 2, "::", "4000::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 3, "2000::", "4000::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 4, "2000::", "3000::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 8, "2000::", "2100::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 16, "2001::", "2002::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 48, "2001::", "2001:0:1::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 56, "2001::", "2001:0:0:0100::");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 65, "2001::", "2001::8000:0:0:0");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 66, "2001::", "2001::4000:0:0:0");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 127, "2001::", "2001::2");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 128, "2001::", "2001::1");
test_in_addr_prefix_range_one(AF_INET6, "2001::", 129, NULL, NULL);
}
static void test_in_addr_to_string_one(int f, const char *addr) {