+static void destroy_lookup(struct resolv_lookup *lookup)
+{
+ debug(lookup->resolv, "lookup %p id %d ipv4 %p ipv6 %p",
+ lookup, lookup->id, lookup->ipv4_query, lookup->ipv6_query);
+
+ if (lookup->ipv4_query) {
+ g_queue_remove(lookup->resolv->query_queue,
+ lookup->ipv4_query);
+ destroy_query(lookup->ipv4_query);
+ }
+
+ if (lookup->ipv6_query) {
+ g_queue_remove(lookup->resolv->query_queue,
+ lookup->ipv6_query);
+ destroy_query(lookup->ipv6_query);
+ }
+
+ g_free(lookup->results);
+ g_free(lookup);
+}
+
+static void find_srcaddr(struct sort_result *res)
+{
+ socklen_t sl = sizeof(res->src);
+ int fd;
+
+ fd = socket(res->dst.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC,
+ IPPROTO_IP);
+ if (fd < 0)
+ return;
+
+ if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0)
+ goto out;
+
+ if (getsockname(fd, &res->src.sa, &sl) < 0)
+ goto out;
+
+ res->reachable = true;
+
+out:
+ close(fd);
+}
+
+struct gai_table
+{
+ unsigned char addr[NS_IN6ADDRSZ];
+ int mask;
+ int value;
+};
+
+static const struct gai_table gai_labels[] = {
+ {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
+ .mask = 128,
+ .value = 0,
+ }, {
+ .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 16,
+ .value = 2,
+ }, {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 96,
+ .value = 3,
+ }, {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 96,
+ .value = 4,
+ }, {
+ /* Variations from RFC 3484, matching glibc behaviour */
+ .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 10,
+ .value = 5,
+ }, {
+ .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 7,
+ .value = 6,
+ }, {
+ .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 32,
+ .value = 7,
+ }, {
+ /* catch-all */
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 0,
+ .value = 1,
+ }
+};
+
+static const struct gai_table gai_precedences[] = {
+ {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
+ .mask = 128,
+ .value = 50,
+ }, {
+ .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 16,
+ .value = 30,
+ }, {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 96,
+ .value = 20,
+ }, {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 96,
+ .value = 10,
+ }, {
+ .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+ .mask = 0,
+ .value = 40,
+ }
+};
+
+static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
+
+static bool mask_compare(const unsigned char *one,
+ const unsigned char *two, int mask)
+{
+ if (mask > 8) {
+ if (memcmp(one, two, mask / 8))
+ return false;
+ one += mask / 8;
+ two += mask / 8;
+ mask %= 8;
+ }
+
+ if (mask && ((*one ^ *two) >> (8 - mask)))
+ return false;
+
+ return true;
+}
+
+static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
+{
+ struct sockaddr_in *sin = (void *)sa;
+ struct sockaddr_in6 *sin6 = (void *)sa;
+ void *addr;
+
+ if (sa->sa_family == AF_INET) {
+ addr = v4mapped;
+ memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
+ } else
+ addr = &sin6->sin6_addr;
+
+ while (1) {
+ if (mask_compare(addr, tbl->addr, tbl->mask))
+ return tbl->value;
+ tbl++;
+ }
+}
+
+#define DQUAD(_a,_b,_c,_d) ( (((uint32_t)_a)<<24) | (((uint32_t)_b)<<16) | \
+ (((uint32_t)_c)<<8) | ((uint32_t)_d) )
+#define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
+
+#define RFC3484_SCOPE_LINK 2
+#define RFC3484_SCOPE_SITE 5
+#define RFC3484_SCOPE_GLOBAL 14
+
+static int addr_scope(struct sockaddr *sa)
+{
+ if (sa->sa_family == AF_INET) {
+ struct sockaddr_in *sin = (void *)sa;
+ uint32_t addr = ntohl(sin->sin_addr.s_addr);
+
+ if (V4MATCH(addr, 169,254,0,0, 16) ||
+ V4MATCH(addr, 127,0,0,0, 8))
+ return RFC3484_SCOPE_LINK;
+
+ /* Site-local */
+ if (V4MATCH(addr, 10,0,0,0, 8) ||
+ V4MATCH(addr, 172,16,0,0, 12) ||
+ V4MATCH(addr, 192,168,0,0, 16))
+ return RFC3484_SCOPE_SITE;
+
+ /* Global */
+ return RFC3484_SCOPE_GLOBAL;
+ } else {
+ struct sockaddr_in6 *sin6 = (void *)sa;
+
+ /* Multicast addresses have a 4-bit scope field */
+ if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
+ return sin6->sin6_addr.s6_addr[1] & 0xf;
+
+ if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
+ IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
+ return RFC3484_SCOPE_LINK;
+
+ if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
+ return RFC3484_SCOPE_SITE;
+
+ return RFC3484_SCOPE_GLOBAL;
+ }
+}
+
+static int rfc3484_compare(const void *__one, const void *__two)
+{
+ const struct sort_result *one = __one;
+ const struct sort_result *two = __two;
+
+ /* Rule 1: Avoid unusable destinations */
+ if (one->reachable && !two->reachable)
+ return -1;
+ else if (two->reachable && !one->reachable)
+ return 1;
+
+ /* Rule 2: Prefer matching scope */
+ if (one->dst_scope == one->src_scope &&
+ two->dst_scope != two->src_scope)
+ return -1;
+ else if (two->dst_scope == two->src_scope &&
+ one->dst_scope != one->src_scope)
+ return 1;
+
+ /* Rule 3: Avoid deprecated addresses */
+
+ /* Rule 4: Prefer home addresses */
+
+ /* Rule 5: Prefer matching label */
+ if (one->dst_label == one->src_label &&
+ two->dst_label != two->src_label)
+ return -1;
+ else if (two->dst_label == two->src_label &&
+ one->dst_label != one->src_label)
+ return 1;
+
+ /* Rule 6: Prefer higher precedence */
+ if (one->precedence > two->precedence)
+ return -1;
+ else if (two->precedence > one->precedence)
+ return 1;
+
+ /* Rule 7: Prefer native transport */
+
+ /* Rule 8: Prefer smaller scope */
+ if (one->dst_scope != two->dst_scope)
+ return one->dst_scope - two->dst_scope;
+
+ /* Rule 9: Use longest matching prefix */
+ if (one->dst.sa.sa_family == AF_INET) {
+ /*
+ * Rule 9 is meaningless and counterproductive for Legacy IP
+ * unless perhaps we can tell that it's actually on the local
+ * subnet. But we don't (yet) have local interface config
+ * information, so do nothing here for Legacy IP for now.
+ */
+ } else {
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ guint32 cmp_one, cmp_two;
+
+ cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
+ one->dst.sin6.sin6_addr.s6_addr32[i];
+ cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
+ two->dst.sin6.sin6_addr.s6_addr32[i];
+
+ if (!cmp_two && !cmp_one)
+ continue;
+
+ if (cmp_one && !cmp_two)
+ return 1;
+ if (cmp_two && !cmp_one)
+ return -1;
+
+ /* g_bit_storage() is effectively fls() */
+ cmp_one = g_bit_storage(ntohl(cmp_one));
+ cmp_two = g_bit_storage(ntohl(cmp_two));
+
+ if (cmp_one == cmp_two)
+ break;
+
+ return cmp_one - cmp_two;
+ }
+ }
+
+
+ /* Rule 10: Otherwise, leave the order unchanged */
+ if (one < two)
+ return -1;
+ else
+ return 1;
+}
+
+static void rfc3484_sort_results(struct resolv_lookup *lookup)
+{
+ int i;
+
+ for (i = 0; i < lookup->nr_results; i++) {
+ struct sort_result *res = &lookup->results[i];
+ find_srcaddr(res);
+ res->precedence = match_gai_table(&res->dst.sa,
+ gai_precedences);
+ res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
+ res->src_label = match_gai_table(&res->src.sa, gai_labels);
+ res->dst_scope = addr_scope(&res->dst.sa);
+ res->src_scope = addr_scope(&res->src.sa);
+ }
+
+ qsort(lookup->results, lookup->nr_results,
+ sizeof(struct sort_result), rfc3484_compare);
+}
+
+static void sort_and_return_results(struct resolv_lookup *lookup)
+{
+ char buf[INET6_ADDRSTRLEN + 1];
+ GResolvResultStatus status;
+ char **results = g_try_new0(char *, lookup->nr_results + 1);
+ GResolvResultFunc result_func = lookup->result_func;
+ void *result_data = lookup->result_data;
+ int i, n = 0;
+
+ if (!results)
+ return;
+
+ memset(buf, 0, INET6_ADDRSTRLEN + 1);
+
+ rfc3484_sort_results(lookup);
+
+ for (i = 0; i < lookup->nr_results; i++) {
+ if (lookup->results[i].dst.sa.sa_family == AF_INET) {
+ if (!inet_ntop(AF_INET,
+ &lookup->results[i].dst.sin.sin_addr,
+ buf, sizeof(buf) - 1))
+ continue;
+ } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
+ if (!inet_ntop(AF_INET6,
+ &lookup->results[i].dst.sin6.sin6_addr,
+ buf, sizeof(buf) - 1))
+ continue;
+ } else
+ continue;
+
+ results[n++] = g_strdup(buf);
+ }
+
+ results[n++] = NULL;
+
+ if (lookup->resolv->result_family == AF_INET)
+ status = lookup->ipv4_status;
+ else if (lookup->resolv->result_family == AF_INET6)
+ status = lookup->ipv6_status;
+ else {
+ if (lookup->ipv6_status == G_RESOLV_RESULT_STATUS_SUCCESS)
+ status = lookup->ipv6_status;
+ else
+ status = lookup->ipv4_status;
+ }
+
+ debug(lookup->resolv, "lookup %p received %d results", lookup, n-1);
+
+ g_queue_remove(lookup->resolv->lookup_queue, lookup);
+ destroy_lookup(lookup);
+
+ result_func(status, results, result_data);
+
+ g_strfreev(results);
+}
+