dns: add reverse DNS IPv6 entries to dnsmasq

https://bugzilla.gnome.org/show_bug.cgi?id=767174

src/dns-manager/nm-dns-dnsmasq.c

@@ -219,6 +219,8 @@ add_ip6_config (NMDnsDnsmasq *self, GVariantBuilder *servers, NMIP6Config *ip6,
 	nnameservers = nm_ip6_config_get_num_nameservers (ip6);
 
 	if (split) {
+		char **domains, **iter;
+
 		if (nnameservers == 0)
 			return FALSE;
 
@@ -248,6 +250,16 @@ add_ip6_config (NMDnsDnsmasq *self, GVariantBuilder *servers, NMIP6Config *ip6,
 				}
 			}
 
+			/* Ensure reverse-DNS works by directing queries for ip6.arpa
+			 * domains to the split domain's nameserver.
+			 */
+			domains = nm_dns_utils_get_ip6_rdns_domains (ip6);
+			if (domains) {
+				for (iter = domains; iter && *iter; iter++)
+					add_dnsmasq_nameserver (self, servers, buf, *iter);
+				g_strfreev (domains);
+			}
+
 			g_free (buf);
 		}
 	}

src/dns-manager/nm-dns-utils.c

@@ -57,5 +57,36 @@ nm_dns_utils_get_ip4_rdns_domains (NMIP4Config *ip4)
 	strv = (char **) g_ptr_array_free (domains, (domains->len == 1));
 
 	return _nm_utils_strv_cleanup (strv, FALSE, FALSE, TRUE);
-
+}
+
+char **
+nm_dns_utils_get_ip6_rdns_domains (NMIP6Config *ip6)
+{
+	char **strv;
+	GPtrArray *domains = NULL;
+	int i;
+
+	g_return_val_if_fail (ip6 != NULL, NULL);
+
+	domains = g_ptr_array_sized_new (5);
+
+	for (i = 0; i < nm_ip6_config_get_num_addresses (ip6); i++) {
+		const NMPlatformIP6Address *address = nm_ip6_config_get_address (ip6, i);
+
+		nm_utils_get_reverse_dns_domains_ip6 (&address->address, address->plen, domains);
+	}
+
+	for (i = 0; i < nm_ip6_config_get_num_routes (ip6); i++) {
+		const NMPlatformIP6Route *route = nm_ip6_config_get_route (ip6, i);
+
+		nm_utils_get_reverse_dns_domains_ip6 (&route->network, route->plen, domains);
+	}
+
+	/* Terminating NULL so we can use g_strfreev() to free it */
+	g_ptr_array_add (domains, NULL);
+
+	/* Free the array and return NULL if the only element was the ending NULL */
+	strv = (char **) g_ptr_array_free (domains, (domains->len == 1));
+
+	return _nm_utils_strv_cleanup (strv, FALSE, FALSE, TRUE);
 }

src/dns-manager/nm-dns-utils.h

@@ -21,8 +21,10 @@
 #define __NETWORKMANAGER_DNS_UTILS_H__
 
 #include "nm-ip4-config.h"
+#include "nm-ip6-config.h"
 
 char **nm_dns_utils_get_ip4_rdns_domains (NMIP4Config *ip4);
+char **nm_dns_utils_get_ip6_rdns_domains (NMIP6Config *ip6);
 
 #endif  /* NM_DNS_UTILS_H */
 

src/nm-core-utils.c

@@ -3318,3 +3318,60 @@ nm_utils_get_reverse_dns_domains_ip4 (guint32 addr, guint8 plen, GPtrArray *doma
 		ip2 += 1 << ((32 - plen) & ~7);
 	}
 }
+
+/**
+ * nm_utils_get_reverse_dns_domains_ip6:
+ * @addr: IPv6 address
+ * @plen: prefix length
+ * @domains: array for results
+ *
+ * Creates reverse DNS domains for the given address and prefix length, and
+ * append them to @domains.
+ */
+void
+nm_utils_get_reverse_dns_domains_ip6 (const struct in6_addr *ip, guint8 plen, GPtrArray *domains)
+{
+	struct in6_addr addr;
+	guint nibbles, bits, entries;
+	int i, j;
+	gsize len0, len;
+	char *str, *s;
+
+	g_return_if_fail (domains);
+	g_return_if_fail (plen <= 128);
+
+	if (!plen)
+		return;
+
+	memcpy (&addr, ip, sizeof (struct in6_addr));
+	nm_utils_ip6_address_clear_host_address (&addr, &addr, plen);
+
+	/* Number of nibbles to include in domains */
+	nibbles = (plen - 1) / 4 + 1;
+	/* Prefix length in nibble */
+	bits = plen - ((plen - 1) / 4 * 4);
+	/* Number of domains */
+	entries = 1 << (4 - bits);
+
+	len0 = NM_STRLEN ("ip6.arpa") + (2 * nibbles) + 1;
+
+#define N_SHIFT(x) ((x) % 2 ? 0 : 4)
+
+	for (i = 0; i < entries; i++) {
+		len = len0;
+		str = s = g_malloc (len);
+
+		for (j = nibbles - 1; j >= 0; j--)
+			nm_utils_strbuf_append (&s,
+			                        &len,
+			                        "%x.",
+			                        (addr.s6_addr[j / 2] >> N_SHIFT (j)) & 0xf);
+		nm_utils_strbuf_append_str (&s, &len, "ip6.arpa");
+
+		g_ptr_array_add (domains, str);
+
+		addr.s6_addr[(nibbles - 1) / 2] += 1 << N_SHIFT (nibbles - 1);
+	}
+
+#undef N_SHIFT
+}

src/nm-core-utils.h

@@ -407,5 +407,6 @@ gboolean nm_utils_ip4_address_is_link_local (in_addr_t addr);
 const char *nm_utils_dnsmasq_status_to_string (int status, char *dest, gsize size);
 
 void nm_utils_get_reverse_dns_domains_ip4 (guint32 ip, guint8 plen, GPtrArray *domains);
+void nm_utils_get_reverse_dns_domains_ip6 (const struct in6_addr *ip, guint8 plen, GPtrArray *domains);
 
 #endif /* __NM_CORE_UTILS_H__ */

src/tests/test-general.c

@@ -1361,8 +1361,6 @@ test_duplicate_decl_specifier (void)
 	v_result[0] = TEST_MAX (v_const[0], nmtst_get_rand_int () % 5) + v2;
 }
 
-/*****************************************************************************/
-
 static void
 test_reverse_dns_ip4 (void)
 {
@@ -1427,6 +1425,60 @@ test_reverse_dns_ip4 (void)
 	g_ptr_array_unref (domains);
 }
 
+static void
+test_reverse_dns_ip6 (void)
+{
+	struct in6_addr addr;
+	GPtrArray *domains = g_ptr_array_new_full (8, g_free);
+
+	inet_pton (AF_INET6, "1234::56", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 16, domains);
+	g_assert_cmpuint (domains->len, ==, 1);
+	g_assert_cmpstr (domains->pdata[0], ==, "4.3.2.1.ip6.arpa");
+
+	g_ptr_array_set_size (domains, 0);
+
+	inet_pton (AF_INET6, "1234::56", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 17, domains);
+	g_assert_cmpuint (domains->len, ==, 8);
+	g_assert_cmpstr (domains->pdata[0], ==, "0.4.3.2.1.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[1], ==, "1.4.3.2.1.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[7], ==, "7.4.3.2.1.ip6.arpa");
+
+	g_ptr_array_set_size (domains, 0);
+
+	inet_pton (AF_INET6, "2001:db8::", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 29, domains);
+	g_assert_cmpuint (domains->len, ==, 8);
+	g_assert_cmpstr (domains->pdata[0], ==, "8.b.d.0.1.0.0.2.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[1], ==, "9.b.d.0.1.0.0.2.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[7], ==, "f.b.d.0.1.0.0.2.ip6.arpa");
+
+	g_ptr_array_set_size (domains, 0);
+
+	inet_pton (AF_INET6, "0123:4567:89ab:cdef::", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 63, domains);
+	g_assert_cmpuint (domains->len, ==, 2);
+	g_assert_cmpstr (domains->pdata[0], ==, "e.e.d.c.b.a.9.8.7.6.5.4.3.2.1.0.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[1], ==, "f.e.d.c.b.a.9.8.7.6.5.4.3.2.1.0.ip6.arpa");
+
+	g_ptr_array_set_size (domains, 0);
+
+	inet_pton (AF_INET6, "fec0:1234:5678:9ab0::", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 61, domains);
+	g_assert_cmpuint (domains->len, ==, 8);
+	g_assert_cmpstr (domains->pdata[0], ==, "0.b.a.9.8.7.6.5.4.3.2.1.0.c.e.f.ip6.arpa");
+	g_assert_cmpstr (domains->pdata[7], ==, "7.b.a.9.8.7.6.5.4.3.2.1.0.c.e.f.ip6.arpa");
+
+	g_ptr_array_set_size (domains, 0);
+
+	inet_pton (AF_INET6, "0123:4567:89ab:cdee::", &addr);
+	nm_utils_get_reverse_dns_domains_ip6 (&addr, 0, domains);
+	g_assert_cmpuint (domains->len, ==, 0);
+
+	g_ptr_array_unref (domains);
+}
+
 /*****************************************************************************/
 
 NMTST_DEFINE ();
@@ -1464,6 +1516,7 @@ main (int argc, char **argv)
 	g_test_add_func ("/general/duplicate_decl_specifier", test_duplicate_decl_specifier);
 
 	g_test_add_func ("/general/reverse_dns/ip4", test_reverse_dns_ip4);
+	g_test_add_func ("/general/reverse_dns/ip6", test_reverse_dns_ip6);
 
 	return g_test_run ();
 }