resolve: move dns routines into shared

3 files changed, 855 insertions, 0 deletions

diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
new file mode 100644
index 000000000..20a44ce4e
--- /dev/null
+++ b/src/shared/dns-domain.c
@@ -0,0 +1,613 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+ ***/
+
+#ifdef HAVE_LIBIDN
+#include <idna.h>
+#include <stringprep.h>
+#endif
+
+#include "dns-domain.h"
+
+int dns_label_unescape(const char **name, char *dest, size_t sz) {
+        const char *n;
+        char *d;
+        int r = 0;
+
+        assert(name);
+        assert(*name);
+        assert(dest);
+
+        n = *name;
+        d = dest;
+
+        for (;;) {
+                if (*n == '.') {
+                        n++;
+                        break;
+                }
+
+                if (*n == 0)
+                        break;
+
+                if (sz <= 0)
+                        return -ENOSPC;
+
+                if (r >= DNS_LABEL_MAX)
+                        return -EINVAL;
+
+                if (*n == '\\') {
+                        /* Escaped character */
+
+                        n++;
+
+                        if (*n == 0)
+                                /* Ending NUL */
+                                return -EINVAL;
+
+                        else if (*n == '\\' || *n == '.') {
+                                /* Escaped backslash or dot */
+                                *(d++) = *(n++);
+                                sz--;
+                                r++;
+
+                        } else if (n[0] >= '0' && n[0] <= '9') {
+                                unsigned k;
+
+                                /* Escaped literal ASCII character */
+
+                                if (!(n[1] >= '0' && n[1] <= '9') ||
+                                    !(n[2] >= '0' && n[2] <= '9'))
+                                        return -EINVAL;
+
+                                k = ((unsigned) (n[0] - '0') * 100) +
+                                        ((unsigned) (n[1] - '0') * 10) +
+                                        ((unsigned) (n[2] - '0'));
+
+                                /* Don't allow CC characters or anything that doesn't fit in 8bit */
+                                if (k < ' ' || k > 255 || k == 127)
+                                        return -EINVAL;
+
+                                *(d++) = (char) k;
+                                sz--;
+                                r++;
+
+                                n += 3;
+                        } else
+                                return -EINVAL;
+
+                } else if ((uint8_t) *n >= (uint8_t) ' ' && *n != 127) {
+
+                        /* Normal character */
+                        *(d++) = *(n++);
+                        sz--;
+                        r++;
+                } else
+                        return -EINVAL;
+        }
+
+        /* Empty label that is not at the end? */
+        if (r == 0 && *n)
+                return -EINVAL;
+
+        if (sz >= 1)
+                *d = 0;
+
+        *name = n;
+        return r;
+}
+
+int dns_label_escape(const char *p, size_t l, char **ret) {
+        _cleanup_free_ char *s = NULL;
+        char *q;
+        int r;
+
+        assert(p);
+        assert(ret);
+
+        if (l > DNS_LABEL_MAX)
+                return -EINVAL;
+
+        s = malloc(l * 4 + 1);
+        if (!s)
+                return -ENOMEM;
+
+        q = s;
+        while (l > 0) {
+
+                if (*p == '.' || *p == '\\') {
+
+                        /* Dot or backslash */
+                        *(q++) = '\\';
+                        *(q++) = *p;
+
+                } else if (*p == '_' ||
+                           *p == '-' ||
+                           (*p >= '0' && *p <= '9') ||
+                           (*p >= 'a' && *p <= 'z') ||
+                           (*p >= 'A' && *p <= 'Z')) {
+
+                        /* Proper character */
+                        *(q++) = *p;
+                } else if ((uint8_t) *p >= (uint8_t) ' ' && *p != 127) {
+
+                        /* Everything else */
+                        *(q++) = '\\';
+                        *(q++) = '0' + (char) ((uint8_t) *p / 100);
+                        *(q++) = '0' + (char) (((uint8_t) *p / 10) % 10);
+                        *(q++) = '0' + (char) ((uint8_t) *p % 10);
+
+                } else
+                        return -EINVAL;
+
+                p++;
+                l--;
+        }
+
+        *q = 0;
+        *ret = s;
+        r = q - s;
+        s = NULL;
+
+        return r;
+}
+
+int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
+#ifdef HAVE_LIBIDN
+        _cleanup_free_ uint32_t *input = NULL;
+        size_t input_size;
+        const char *p;
+        bool contains_8bit = false;
+
+        assert(encoded);
+        assert(decoded);
+        assert(decoded_max >= DNS_LABEL_MAX);
+
+        if (encoded_size <= 0)
+                return 0;
+
+        for (p = encoded; p < encoded + encoded_size; p++)
+                if ((uint8_t) *p > 127)
+                        contains_8bit = true;
+
+        if (!contains_8bit)
+                return 0;
+
+        input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
+        if (!input)
+                return -ENOMEM;
+
+        if (idna_to_ascii_4i(input, input_size, decoded, 0) != 0)
+                return -EINVAL;
+
+        return strlen(decoded);
+#else
+        return 0;
+#endif
+}
+
+int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
+#ifdef HAVE_LIBIDN
+        size_t input_size, output_size;
+        _cleanup_free_ uint32_t *input = NULL;
+        _cleanup_free_ char *result = NULL;
+        uint32_t *output = NULL;
+        size_t w;
+
+        /* To be invoked after unescaping */
+
+        assert(encoded);
+        assert(decoded);
+
+        if (encoded_size < sizeof(IDNA_ACE_PREFIX)-1)
+                return 0;
+
+        if (memcmp(encoded, IDNA_ACE_PREFIX, sizeof(IDNA_ACE_PREFIX) -1) != 0)
+                return 0;
+
+        input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
+        if (!input)
+                return -ENOMEM;
+
+        output_size = input_size;
+        output = newa(uint32_t, output_size);
+
+        idna_to_unicode_44i(input, input_size, output, &output_size, 0);
+
+        result = stringprep_ucs4_to_utf8(output, output_size, NULL, &w);
+        if (!result)
+                return -ENOMEM;
+        if (w <= 0)
+                return 0;
+        if (w+1 > decoded_max)
+                return -EINVAL;
+
+        memcpy(decoded, result, w+1);
+        return w;
+#else
+        return 0;
+#endif
+}
+
+int dns_name_normalize(const char *s, char **_ret) {
+        _cleanup_free_ char *ret = NULL;
+        size_t n = 0, allocated = 0;
+        const char *p = s;
+        bool first = true;
+        int r;
+
+        assert(s);
+
+        for (;;) {
+                _cleanup_free_ char *t = NULL;
+                char label[DNS_LABEL_MAX];
+                int k;
+
+                r = dns_label_unescape(&p, label, sizeof(label));
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        if (*p != 0)
+                                return -EINVAL;
+                        break;
+                }
+
+                k = dns_label_undo_idna(label, r, label, sizeof(label));
+                if (k < 0)
+                        return k;
+                if (k > 0)
+                        r = k;
+
+                r = dns_label_escape(label, r, &t);
+                if (r < 0)
+                        return r;
+
+                if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1))
+                        return -ENOMEM;
+
+                if (!first)
+                        ret[n++] = '.';
+                else
+                        first = false;
+
+                memcpy(ret + n, t, r);
+                n += r;
+        }
+
+        if (n > DNS_NAME_MAX)
+                return -EINVAL;
+
+        if (!GREEDY_REALLOC(ret, allocated, n + 1))
+                return -ENOMEM;
+
+        ret[n] = 0;
+
+        if (_ret) {
+                *_ret = ret;
+                ret = NULL;
+        }
+
+        return 0;
+}
+
+unsigned long dns_name_hash_func(const void *s, const uint8_t hash_key[HASH_KEY_SIZE]) {
+        const char *p = s;
+        unsigned long ul = hash_key[0];
+        int r;
+
+        assert(p);
+
+        while (*p) {
+                char label[DNS_LABEL_MAX+1];
+                int k;
+
+                r = dns_label_unescape(&p, label, sizeof(label));
+                if (r < 0)
+                        break;
+
+                k = dns_label_undo_idna(label, r, label, sizeof(label));
+                if (k < 0)
+                        break;
+                if (k > 0)
+                        r = k;
+
+                label[r] = 0;
+                ascii_strlower(label);
+
+                ul = ul * hash_key[1] + ul + string_hash_func(label, hash_key);
+        }
+
+        return ul;
+}
+
+int dns_name_compare_func(const void *a, const void *b) {
+        const char *x = a, *y = b;
+        int r, q, k, w;
+
+        assert(a);
+        assert(b);
+
+        for (;;) {
+                char la[DNS_LABEL_MAX+1], lb[DNS_LABEL_MAX+1];
+
+                if (*x == 0 && *y == 0)
+                        return 0;
+
+                r = dns_label_unescape(&x, la, sizeof(la));
+                q = dns_label_unescape(&y, lb, sizeof(lb));
+                if (r < 0 || q < 0)
+                        return r - q;
+
+                k = dns_label_undo_idna(la, r, la, sizeof(la));
+                w = dns_label_undo_idna(lb, q, lb, sizeof(lb));
+                if (k < 0 || w < 0)
+                        return k - w;
+                if (k > 0)
+                        r = k;
+                if (w > 0)
+                        r = w;
+
+                la[r] = lb[q] = 0;
+                r = strcasecmp(la, lb);
+                if (r != 0)
+                        return r;
+        }
+}
+
+const struct hash_ops dns_name_hash_ops = {
+        .hash = dns_name_hash_func,
+        .compare = dns_name_compare_func
+};
+
+int dns_name_equal(const char *x, const char *y) {
+        int r, q, k, w;
+
+        assert(x);
+        assert(y);
+
+        for (;;) {
+                char la[DNS_LABEL_MAX+1], lb[DNS_LABEL_MAX+1];
+
+                if (*x == 0 && *y == 0)
+                        return true;
+
+                r = dns_label_unescape(&x, la, sizeof(la));
+                if (r < 0)
+                        return r;
+
+                k = dns_label_undo_idna(la, r, la, sizeof(la));
+                if (k < 0)
+                        return k;
+                if (k > 0)
+                        r = k;
+
+                q = dns_label_unescape(&y, lb, sizeof(lb));
+                if (q < 0)
+                        return q;
+                w = dns_label_undo_idna(lb, q, lb, sizeof(lb));
+                if (w < 0)
+                        return w;
+                if (w > 0)
+                        q = w;
+
+                la[r] = lb[q] = 0;
+                if (strcasecmp(la, lb))
+                        return false;
+        }
+}
+
+int dns_name_endswith(const char *name, const char *suffix) {
+        const char *n, *s, *saved_n = NULL;
+        int r, q, k, w;
+
+        assert(name);
+        assert(suffix);
+
+        n = name;
+        s = suffix;
+
+        for (;;) {
+                char ln[DNS_LABEL_MAX+1], ls[DNS_LABEL_MAX+1];
+
+                r = dns_label_unescape(&n, ln, sizeof(ln));
+                if (r < 0)
+                        return r;
+                k = dns_label_undo_idna(ln, r, ln, sizeof(ln));
+                if (k < 0)
+                        return k;
+                if (k > 0)
+                        r = k;
+
+                if (!saved_n)
+                        saved_n = n;
+
+                q = dns_label_unescape(&s, ls, sizeof(ls));
+                if (q < 0)
+                        return q;
+                w = dns_label_undo_idna(ls, q, ls, sizeof(ls));
+                if (w < 0)
+                        return w;
+                if (w > 0)
+                        q = w;
+
+                if (r == 0 && q == 0)
+                        return true;
+                if (r == 0 && saved_n == n)
+                        return false;
+
+                ln[r] = ls[q] = 0;
+
+                if (r != q || strcasecmp(ln, ls)) {
+
+                        /* Not the same, let's jump back, and try with the next label again */
+                        s = suffix;
+                        n = saved_n;
+                        saved_n = NULL;
+                }
+        }
+}
+
+int dns_name_reverse(int family, const union in_addr_union *a, char **ret) {
+        const uint8_t *p;
+        int r;
+
+        assert(a);
+        assert(ret);
+
+        p = (const uint8_t*) a;
+
+        if (family == AF_INET)
+                r = asprintf(ret, "%u.%u.%u.%u.in-addr.arpa", p[3], p[2], p[1], p[0]);
+        else if (family == AF_INET6)
+                r = asprintf(ret, "%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.ip6.arpa",
+                             hexchar(p[15] & 0xF), hexchar(p[15] >> 4), hexchar(p[14] & 0xF), hexchar(p[14] >> 4),
+                             hexchar(p[13] & 0xF), hexchar(p[13] >> 4), hexchar(p[12] & 0xF), hexchar(p[12] >> 4),
+                             hexchar(p[11] & 0xF), hexchar(p[11] >> 4), hexchar(p[10] & 0xF), hexchar(p[10] >> 4),
+                             hexchar(p[ 9] & 0xF), hexchar(p[ 9] >> 4), hexchar(p[ 8] & 0xF), hexchar(p[ 8] >> 4),
+                             hexchar(p[ 7] & 0xF), hexchar(p[ 7] >> 4), hexchar(p[ 6] & 0xF), hexchar(p[ 6] >> 4),
+                             hexchar(p[ 5] & 0xF), hexchar(p[ 5] >> 4), hexchar(p[ 4] & 0xF), hexchar(p[ 4] >> 4),
+                             hexchar(p[ 3] & 0xF), hexchar(p[ 3] >> 4), hexchar(p[ 2] & 0xF), hexchar(p[ 2] >> 4),
+                             hexchar(p[ 1] & 0xF), hexchar(p[ 1] >> 4), hexchar(p[ 0] & 0xF), hexchar(p[ 0] >> 4));
+        else
+                return -EAFNOSUPPORT;
+        if (r < 0)
+                return -ENOMEM;
+
+        return 0;
+}
+
+int dns_name_address(const char *p, int *family, union in_addr_union *address) {
+        int r;
+
+        assert(p);
+        assert(family);
+        assert(address);
+
+        r = dns_name_endswith(p, "in-addr.arpa");
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                uint8_t a[4];
+                unsigned i;
+
+                for (i = 0; i < ELEMENTSOF(a); i++) {
+                        char label[DNS_LABEL_MAX+1];
+
+                        r = dns_label_unescape(&p, label, sizeof(label));
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                return -EINVAL;
+                        if (r > 3)
+                                return -EINVAL;
+
+                        r = safe_atou8(label, &a[i]);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = dns_name_equal(p, "in-addr.arpa");
+                if (r <= 0)
+                        return r;
+
+                *family = AF_INET;
+                address->in.s_addr = htobe32(((uint32_t) a[3] << 24) |
+                                             ((uint32_t) a[2] << 16) |
+                                             ((uint32_t) a[1] << 8) |
+                                              (uint32_t) a[0]);
+
+                return 1;
+        }
+
+        r = dns_name_endswith(p, "ip6.arpa");
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                struct in6_addr a;
+                unsigned i;
+
+                for (i = 0; i < ELEMENTSOF(a.s6_addr); i++) {
+                        char label[DNS_LABEL_MAX+1];
+                        int x, y;
+
+                        r = dns_label_unescape(&p, label, sizeof(label));
+                        if (r <= 0)
+                                return r;
+                        if (r != 1)
+                                return -EINVAL;
+                        x = unhexchar(label[0]);
+                        if (x < 0)
+                                return -EINVAL;
+
+                        r = dns_label_unescape(&p, label, sizeof(label));
+                        if (r <= 0)
+                                return r;
+                        if (r != 1)
+                                return -EINVAL;
+                        y = unhexchar(label[0]);
+                        if (y < 0)
+                                return -EINVAL;
+
+                        a.s6_addr[ELEMENTSOF(a.s6_addr) - i - 1] = (uint8_t) y << 4 | (uint8_t) x;
+                }
+
+                r = dns_name_equal(p, "ip6.arpa");
+                if (r <= 0)
+                        return r;
+
+                *family = AF_INET6;
+                address->in6 = a;
+                return 1;
+        }
+
+        return 0;
+}
+
+int dns_name_root(const char *name) {
+        char label[DNS_LABEL_MAX+1];
+        int r;
+
+        assert(name);
+
+        r = dns_label_unescape(&name, label, sizeof(label));
+        if (r < 0)
+                return r;
+
+        return r == 0 && *name == 0;
+}
+
+int dns_name_single_label(const char *name) {
+        char label[DNS_LABEL_MAX+1];
+        int r;
+
+        assert(name);
+
+        r = dns_label_unescape(&name, label, sizeof(label));
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return 0;
+
+        r = dns_label_unescape(&name, label, sizeof(label));
+        if (r < 0)
+                return r;
+
+        return r == 0 && *name == 0;
+}
diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h
new file mode 100644
index 000000000..516d244f7
--- /dev/null
+++ b/src/shared/dns-domain.h
@@ -0,0 +1,50 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+ ***/
+
+#pragma once
+
+
+#include "hashmap.h"
+#include "in-addr-util.h"
+
+#define DNS_LABEL_MAX 63
+#define DNS_NAME_MAX 255
+
+int dns_label_unescape(const char **name, char *dest, size_t sz);
+int dns_label_escape(const char *p, size_t l, char **ret);
+
+int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
+int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
+
+int dns_name_normalize(const char *s, char **_ret);
+
+unsigned long dns_name_hash_func(const void *s, const uint8_t hash_key[HASH_KEY_SIZE]);
+int dns_name_compare_func(const void *a, const void *b);
+extern const struct hash_ops dns_name_hash_ops;
+
+int dns_name_equal(const char *x, const char *y);
+int dns_name_endswith(const char *name, const char *suffix);
+
+int dns_name_reverse(int family, const union in_addr_union *a, char **ret);
+int dns_name_address(const char *p, int *family, union in_addr_union *a);
+
+int dns_name_root(const char *name);
+int dns_name_single_label(const char *name);
diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c
new file mode 100644
index 000000000..527cdd3b5
--- /dev/null
+++ b/src/test/test-dns-domain.c
@@ -0,0 +1,192 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+ ***/
+
+#include "macro.h"
+#include "dns-domain.h"
+
+static void test_dns_label_unescape_one(const char *what, const char *expect, size_t buffer_sz, int ret) {
+        char buffer[buffer_sz];
+        int r;
+
+        r = dns_label_unescape(&what, buffer, buffer_sz);
+        assert_se(r == ret);
+
+        if (r < 0)
+                return;
+
+        assert_se(streq(buffer, expect));
+}
+
+static void test_dns_label_unescape(void) {
+        test_dns_label_unescape_one("hallo", "hallo", 6, 5);
+        test_dns_label_unescape_one("hallo", "hallo", 4, -ENOSPC);
+        test_dns_label_unescape_one("", "", 10, 0);
+        test_dns_label_unescape_one("hallo\\.foobar", "hallo.foobar", 20, 12);
+        test_dns_label_unescape_one("hallo.foobar", "hallo", 10, 5);
+        test_dns_label_unescape_one("hallo\n.foobar", "hallo", 20, -EINVAL);
+        test_dns_label_unescape_one("hallo\\", "hallo", 20, -EINVAL);
+        test_dns_label_unescape_one("hallo\\032 ", "hallo  ", 20, 7);
+        test_dns_label_unescape_one(".", "", 20, 0);
+        test_dns_label_unescape_one("..", "", 20, -EINVAL);
+        test_dns_label_unescape_one(".foobar", "", 20, -EINVAL);
+        test_dns_label_unescape_one("foobar.", "foobar", 20, 6);
+}
+
+static void test_dns_label_escape_one(const char *what, size_t l, const char *expect, int ret) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        r = dns_label_escape(what, l, &t);
+        assert_se(r == ret);
+
+        if (r < 0)
+                return;
+
+        assert_se(streq_ptr(expect, t));
+}
+
+static void test_dns_label_escape(void) {
+        test_dns_label_escape_one("", 0, "", 0);
+        test_dns_label_escape_one("hallo", 5, "hallo", 5);
+        test_dns_label_escape_one("hallo", 6, NULL, -EINVAL);
+        test_dns_label_escape_one("hallo hallo.foobar,waldi", 24, "hallo\\032hallo\\.foobar\\044waldi", 31);
+}
+
+static void test_dns_name_normalize_one(const char *what, const char *expect, int ret) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        r = dns_name_normalize(what, &t);
+        assert_se(r == ret);
+
+        if (r < 0)
+                return;
+
+        assert_se(streq_ptr(expect, t));
+}
+
+static void test_dns_name_normalize(void) {
+        test_dns_name_normalize_one("", "", 0);
+        test_dns_name_normalize_one("f", "f", 0);
+        test_dns_name_normalize_one("f.waldi", "f.waldi", 0);
+        test_dns_name_normalize_one("f \\032.waldi", "f\\032\\032.waldi", 0);
+        test_dns_name_normalize_one("\\000", NULL, -EINVAL);
+        test_dns_name_normalize_one("..", NULL, -EINVAL);
+        test_dns_name_normalize_one(".foobar", NULL, -EINVAL);
+        test_dns_name_normalize_one("foobar.", "foobar", 0);
+        test_dns_name_normalize_one(".", "", 0);
+}
+
+static void test_dns_name_equal_one(const char *a, const char *b, int ret) {
+        int r;
+
+        r = dns_name_equal(a, b);
+        assert_se(r == ret);
+
+        r = dns_name_equal(b, a);
+        assert_se(r == ret);
+}
+
+static void test_dns_name_equal(void) {
+        test_dns_name_equal_one("", "", true);
+        test_dns_name_equal_one("x", "x", true);
+        test_dns_name_equal_one("x", "x.", true);
+        test_dns_name_equal_one("abc.def", "abc.def", true);
+        test_dns_name_equal_one("abc.def", "ABC.def", true);
+        test_dns_name_equal_one("abc.def", "CBA.def", false);
+        test_dns_name_equal_one("", "xxx", false);
+        test_dns_name_equal_one("ab", "a", false);
+        test_dns_name_equal_one("\\000", "xxxx", -EINVAL);
+        test_dns_name_equal_one(".", "", true);
+        test_dns_name_equal_one(".", ".", true);
+        test_dns_name_equal_one("..", "..", -EINVAL);
+}
+
+static void test_dns_name_endswith_one(const char *a, const char *b, int ret) {
+        assert_se(dns_name_endswith(a, b) == ret);
+}
+
+static void test_dns_name_endswith(void) {
+        test_dns_name_endswith_one("", "", true);
+        test_dns_name_endswith_one("", "xxx", false);
+        test_dns_name_endswith_one("xxx", "", true);
+        test_dns_name_endswith_one("x", "x", true);
+        test_dns_name_endswith_one("x", "y", false);
+        test_dns_name_endswith_one("x.y", "y", true);
+        test_dns_name_endswith_one("x.y", "Y", true);
+        test_dns_name_endswith_one("x.y", "x", false);
+        test_dns_name_endswith_one("x.y.z", "Z", true);
+        test_dns_name_endswith_one("x.y.z", "y.Z", true);
+        test_dns_name_endswith_one("x.y.z", "x.y.Z", true);
+        test_dns_name_endswith_one("x.y.z", "waldo", false);
+        test_dns_name_endswith_one("x.y.z.u.v.w", "y.z", false);
+        test_dns_name_endswith_one("x.y.z.u.v.w", "u.v.w", true);
+        test_dns_name_endswith_one("x.y\001.z", "waldo", -EINVAL);
+}
+
+static void test_dns_name_root(void) {
+        assert_se(dns_name_root("") == true);
+        assert_se(dns_name_root(".") == true);
+        assert_se(dns_name_root("xxx") == false);
+        assert_se(dns_name_root("xxx.") == false);
+        assert_se(dns_name_root("..") == -EINVAL);
+}
+
+static void test_dns_name_single_label(void) {
+        assert_se(dns_name_single_label("") == false);
+        assert_se(dns_name_single_label(".") == false);
+        assert_se(dns_name_single_label("..") == -EINVAL);
+        assert_se(dns_name_single_label("x") == true);
+        assert_se(dns_name_single_label("x.") == true);
+        assert_se(dns_name_single_label("xx.yy") == false);
+}
+
+static void test_dns_name_reverse_one(const char *address, const char *name) {
+        _cleanup_free_ char *p = NULL;
+        union in_addr_union a, b = {};
+        int familya, familyb;
+
+        assert_se(in_addr_from_string_auto(address, &familya, &a) >= 0);
+        assert_se(dns_name_reverse(familya, &a, &p) >= 0);
+        assert_se(streq(p, name));
+        assert_se(dns_name_address(p, &familyb, &b) > 0);
+        assert_se(familya == familyb);
+        assert_se(in_addr_equal(familya, &a, &b));
+}
+
+static void test_dns_name_reverse(void) {
+        test_dns_name_reverse_one("47.11.8.15", "15.8.11.47.in-addr.arpa");
+        test_dns_name_reverse_one("fe80::47", "7.4.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa");
+}
+
+int main(int argc, char *argv[]) {
+
+        test_dns_label_unescape();
+        test_dns_label_escape();
+        test_dns_name_normalize();
+        test_dns_name_equal();
+        test_dns_name_endswith();
+        test_dns_name_root();
+        test_dns_name_single_label();
+        test_dns_name_reverse();
+
+        return 0;
+}