rpc: get hostnames of client to allow FQDN based authentication

If FQDNs are used to authenticate clients, then from
this commit forth, the client ip(v4,6) is reverse looked up
using getnameinfo to get a hostname associated with it,
if any, thereby making FQDN-based rpc authentication possible.

Change-Id: I4c5241e7079a2560de79ca15f611e65c0b858f9b
BUG: 903553
Signed-off-by: Rajesh Amaravathi <rajesh@redhat.com>
Reviewed-on: http://review.gluster.org/4439
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/libglusterfs/src/common-utils.c b/libglusterfs/src/common-utils.c
index 22f138614..75b977225 100644
--- a/libglusterfs/src/common-utils.c
+++ b/libglusterfs/src/common-utils.c
@@ -2337,3 +2337,74 @@ gf_ports_reserved (char *blocked_port, gf_boolean_t *ports)
 out:
         return result;
 }
+
+/* Takes in client ip{v4,v6} and returns associated hostname, if any
+ * Also, allocates memory for the hostname.
+ * Returns: 0 for success, -1 for failure
+ */
+int
+gf_get_hostname_from_ip (char *client_ip, char **hostname)
+{
+        int                      ret                          = -1;
+        struct sockaddr         *client_sockaddr              = NULL;
+        struct sockaddr_in       client_sock_in               = {0};
+        struct sockaddr_in6      client_sock_in6              = {0};
+        char                     client_hostname[NI_MAXHOST]  = {0};
+        char                    *client_ip_copy               = NULL;
+        char                    *tmp                          = NULL;
+        char                    *ip                           = NULL;
+
+        /* if ipv4, reverse lookup the hostname to
+         * allow FQDN based rpc authentication
+         */
+        if (valid_ipv4_address (client_ip, strlen (client_ip), 0) == _gf_false) {
+                /* most times, we get a.b.c.d:port form, so check that */
+                client_ip_copy = gf_strdup (client_ip);
+                if (!client_ip_copy)
+                        goto out;
+
+                ip = strtok_r (client_ip_copy, ":", &tmp);
+        } else {
+                ip = client_ip;
+        }
+
+        if (valid_ipv4_address (ip, strlen (ip), 0) == _gf_true) {
+                client_sockaddr = (struct sockaddr *)&client_sock_in;
+                client_sock_in.sin_family = AF_INET;
+                ret = inet_pton (AF_INET, ip,
+                                 (void *)&client_sock_in.sin_addr.s_addr);
+
+        } else if (valid_ipv6_address (ip, strlen (ip), 0) == _gf_true) {
+                client_sockaddr = (struct sockaddr *) &client_sock_in6;
+
+                client_sock_in6.sin6_family = AF_INET6;
+                ret = inet_pton (AF_INET6, ip,
+                                 (void *)&client_sock_in6.sin6_addr);
+        } else {
+                goto out;
+        }
+
+        if (ret != 1) {
+                ret = -1;
+                goto out;
+        }
+
+        ret = getnameinfo (client_sockaddr,
+                           sizeof (*client_sockaddr),
+                           client_hostname, sizeof (client_hostname),
+                           NULL, 0, 0);
+        if (ret) {
+                gf_log ("common-utils", GF_LOG_ERROR,
+                        "Could not lookup hostname of %s : %s",
+                        client_ip, gai_strerror (ret));
+                ret = -1;
+                goto out;
+        }
+
+        *hostname = gf_strdup ((char *)client_hostname);
+ out:
+        if (client_ip_copy)
+                GF_FREE (client_ip_copy);
+
+        return ret;
+}