dns, lib-dns: Added support for async DNS PTR lookups.

diff --git a/src/dns/dns-client.c b/src/dns/dns-client.c
index a8323c033d619d1645500373db6d02a1c9d45be5..825c8001606c6a4a17b9fc9015b7ca93d798d111 100644 (file)
--- a/src/dns/dns-client.c
+++ b/src/dns/dns-client.c
@@ -27,7 +27,8 @@ static void dns_client_destroy(struct dns_client **client);
 
 static int dns_client_input_line(struct dns_client *client, const char *line)
 {
-       struct ip_addr *ips;
+       struct ip_addr *ips, ip;
+       const char *name;
        unsigned int i, ips_count;
        int ret;
 
@@ -48,6 +49,16 @@ static int dns_client_input_line(struct dns_client *client, const char *line)
                                        net_ip2addr(&ips[i]), "\n", NULL));
                        }
                }
+       } else if (strncmp(line, "NAME\t", 5) == 0) {
+               if (net_addr2ip(line+5, &ip) < 0)
+                       o_stream_nsend_str(client->output, "-1\n");
+               else if ((ret = net_gethostbyaddr(&ip, &name)) != 0) {
+                       o_stream_nsend_str(client->output,
+                               t_strdup_printf("%d\n", ret));
+               } else {
+                       o_stream_nsend_str(client->output,
+                               t_strdup_printf("0 %s\n", name));
+               }
        } else if (strcmp(line, "QUIT") == 0) {
                return -1;
        } else {

diff --git a/src/lib-dns/dns-lookup.c b/src/lib-dns/dns-lookup.c
index 4a831d5429e714d2a9bf61a43df7684b0807703a..519ab13dc4eaf70c9d886d829db67b0b14c5a868 100644 (file)
--- a/src/lib-dns/dns-lookup.c
+++ b/src/lib-dns/dns-lookup.c
@@ -16,6 +16,7 @@
 struct dns_lookup {
        int fd;
        char *path;
+       bool ptr_lookup;
 
        struct istream *input;
        struct io *io;
@@ -27,6 +28,7 @@ struct dns_lookup {
        struct dns_lookup_result result;
        struct ip_addr *ips;
        unsigned int ip_idx;
+       char *name;
 
        dns_lookup_callback_t *callback;
        void *context;
@@ -39,6 +41,20 @@ static int dns_lookup_input_line(struct dns_lookup *lookup, const char *line)
        struct dns_lookup_result *result = &lookup->result;
 
        if (result->ips_count == 0) {
+               if (lookup->ptr_lookup) {
+                       /* <ret> [<name>] */
+                       if (strncmp(line, "0 ", 2) == 0) {
+                               result->name = lookup->name =
+                                       i_strdup(line + 2);
+                               result->ret = 0;
+                       } else {
+                               if (str_to_int(line, &result->ret) < 0) {
+                                       return -1;
+                               }
+                               result->error = net_gethosterror(result->ret);
+                       }
+                       return 1;
+               }
                /* first line: <ret> <ip count> */
                if (sscanf(line, "%d %u", &result->ret,
                           &result->ips_count) == 0)
@@ -119,14 +135,14 @@ static void dns_lookup_timeout(struct dns_lookup *lookup)
        dns_lookup_free(&lookup);
 }
 
-#undef dns_lookup
-int dns_lookup(const char *host, const struct dns_lookup_settings *set,
-              dns_lookup_callback_t *callback, void *context,
-              struct dns_lookup **lookup_r)
+static int
+dns_lookup_common(const char *cmd, bool ptr_lookup,
+                 const struct dns_lookup_settings *set,
+                 dns_lookup_callback_t *callback, void *context,
+                 struct dns_lookup **lookup_r)
 {
        struct dns_lookup *lookup;
        struct dns_lookup_result result;
-       const char *cmd;
        int fd;
 
        memset(&result, 0, sizeof(result));
@@ -140,7 +156,6 @@ int dns_lookup(const char *host, const struct dns_lookup_settings *set,
                return -1;
        }
 
-       cmd = t_strconcat("IP\t", host, "\n", NULL);
        if (write_full(fd, cmd, strlen(cmd)) < 0) {
                result.error = t_strdup_printf("write(%s) failed: %m",
                                               set->dns_client_socket_path);
@@ -150,6 +165,7 @@ int dns_lookup(const char *host, const struct dns_lookup_settings *set,
        }
 
        lookup = i_new(struct dns_lookup, 1);
+       lookup->ptr_lookup = ptr_lookup;
        lookup->fd = fd;
        lookup->path = i_strdup(set->dns_client_socket_path);
        lookup->input = i_stream_create_fd(fd, MAX_INBUF_SIZE, FALSE);
@@ -168,6 +184,25 @@ int dns_lookup(const char *host, const struct dns_lookup_settings *set,
        return 0;
 }
 
+#undef dns_lookup
+int dns_lookup(const char *host, const struct dns_lookup_settings *set,
+              dns_lookup_callback_t *callback, void *context,
+              struct dns_lookup **lookup_r)
+{
+       return dns_lookup_common(t_strconcat("IP\t", host, "\n", NULL), FALSE,
+                                set, callback, context, lookup_r);
+}
+
+#undef dns_lookup_ptr
+int dns_lookup_ptr(const struct ip_addr *ip,
+                  const struct dns_lookup_settings *set,
+                  dns_lookup_callback_t *callback, void *context,
+                  struct dns_lookup **lookup_r)
+{
+       const char *cmd = t_strconcat("NAME\t", net_ip2addr(ip), "\n", NULL);
+       return dns_lookup_common(cmd, TRUE, set, callback, context, lookup_r);
+}
+
 static void dns_lookup_free(struct dns_lookup **_lookup)
 {
        struct dns_lookup *lookup = *_lookup;
@@ -181,6 +216,7 @@ static void dns_lookup_free(struct dns_lookup **_lookup)
        if (close(lookup->fd) < 0)
                i_error("close(%s) failed: %m", lookup->path);
 
+       i_free(lookup->name);
        i_free(lookup->ips);
        i_free(lookup->path);
        i_free(lookup);

diff --git a/src/lib-dns/dns-lookup.h b/src/lib-dns/dns-lookup.h
index 3cb364a8d83acd4329cf03bf6765b4d97c39cb0c..8e597ff7708dd8343152361dc31b2cc21e23ad9d 100644 (file)
--- a/src/lib-dns/dns-lookup.h
+++ b/src/lib-dns/dns-lookup.h
@@ -19,8 +19,11 @@ struct dns_lookup_result {
        /* how many milliseconds the lookup took. */
        unsigned int msecs;
 
+       /* for IP lookup: */
        unsigned int ips_count;
        const struct ip_addr *ips;
+       /* for PTR lookup: */
+       const char *name;
 };
 
 typedef void dns_lookup_callback_t(const struct dns_lookup_result *result,
@@ -38,6 +41,15 @@ int dns_lookup(const char *host, const struct dns_lookup_settings *set,
                CALLBACK_TYPECHECK(callback, void (*)( \
                        const struct dns_lookup_result *, typeof(context))), \
                set, (dns_lookup_callback_t *)callback, context, lookup_r)
+int dns_lookup_ptr(const struct ip_addr *ip,
+                  const struct dns_lookup_settings *set,
+                  dns_lookup_callback_t *callback, void *context,
+                  struct dns_lookup **lookup_r) ATTR_NULL(4);
+#define dns_lookup_ptr(host, set, callback, context, lookup_r) \
+       dns_lookup_ptr(host + \
+               CALLBACK_TYPECHECK(callback, void (*)( \
+                       const struct dns_lookup_result *, typeof(context))), \
+               set, (dns_lookup_callback_t *)callback, context, lookup_r)
 /* Abort the DNS lookup without calling the callback. */
 void dns_lookup_abort(struct dns_lookup **lookup);