bearer-mbim: fine-tune bearer IP method reporting

v4: modems/providers may not return DNS servers and not all modems
support DHCP, so lack of DNS servers should not indicate a bearer
IP method of "DHCP".  IP config daemon/scripts already have to handle
missing DNS anyway.

v6: IPv6 requires SLAAC or DHCPv6 as part of the specification, so for
now we assume modems will support it.  Provide all the info the modem
sent, but if there is any missing information use an IP method of
"DHCP" to indicate that info should be obtained via SLAAC/DHCPv6.  Only
use an IP method of "STATIC" when all basic properties are given by
the modem.

1 files changed, 43 insertions, 23 deletions

diff --git a/src/mm-bearer-mbim.c b/src/mm-bearer-mbim.c
index baf419d7..02d27fee 100644
--- a/src/mm-bearer-mbim.c
+++ b/src/mm-bearer-mbim.c
@@ -413,14 +413,13 @@ ip_configuration_query_ready (MbimDevice *device,
             ctx->ip_type == MBIM_CONTEXT_IP_TYPE_IPV4_AND_IPV6) {
             ipv4_config = mm_bearer_ip_config_new ();
 
-            /* We assume that if we have IP and DNS, we can setup static */
+            /* We assume that if we have an IP we can use static configuration.
+             * Not all modems or providers will return DNS servers or even a
+             * gateway, and not all modems support DHCP either. The IP management
+             * daemon/script just has to deal with this...
+             */
             if (ipv4configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_ADDRESS &&
-                ipv4configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_DNS &&
-                ipv4addresscount > 0 &&
-                ipv4dnsservercount > 0) {
-                gchar **strarr;
-                guint i, n;
-
+                ipv4addresscount > 0) {
                 mm_bearer_ip_config_set_method (ipv4_config, MM_BEARER_IP_METHOD_STATIC);
 
                 /* IP address, pick the first one */
@@ -441,8 +440,15 @@ ip_configuration_query_ready (MbimDevice *device,
                     g_free (str);
                     g_object_unref (addr);
                 }
+            } else
+                mm_bearer_ip_config_set_method (ipv4_config, MM_BEARER_IP_METHOD_DHCP);
+
+            /* DNS */
+            if (ipv4configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_DNS &&
+                ipv4dnsservercount > 0) {
+                gchar **strarr;
+                guint i, n;
 
-                /* DNS */
                 strarr = g_new0 (gchar *, ipv4dnsservercount + 1);
                 for (i = 0, n = 0; i < ipv4dnsservercount; i++) {
                     addr = g_inet_address_new_from_bytes ((guint8 *)&ipv4dnsserver[i], G_SOCKET_FAMILY_IPV4);
@@ -452,8 +458,7 @@ ip_configuration_query_ready (MbimDevice *device,
                 }
                 mm_bearer_ip_config_set_dns (ipv4_config, (const gchar **)strarr);
                 g_strfreev (strarr);
-            } else
-                mm_bearer_ip_config_set_method (ipv4_config, MM_BEARER_IP_METHOD_DHCP);
+            }
 
             /* MTU */
             if (ipv4configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_MTU)
@@ -465,30 +470,28 @@ ip_configuration_query_ready (MbimDevice *device,
         if (ctx->ip_type == MBIM_CONTEXT_IP_TYPE_IPV6 ||
             ctx->ip_type == MBIM_CONTEXT_IP_TYPE_IPV4V6 ||
             ctx->ip_type == MBIM_CONTEXT_IP_TYPE_IPV4_AND_IPV6) {
+            gboolean address_set = FALSE;
+            gboolean gateway_set = FALSE;
+            gboolean dns_set = FALSE;
+
             ipv6_config = mm_bearer_ip_config_new ();
 
-            /* We assume that if we have IP and DNS, we can setup static */
             if (ipv6configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_ADDRESS &&
-                ipv6configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_DNS &&
-                ipv6addresscount > 0 &&
-                ipv6dnsservercount > 0) {
-                gchar **strarr;
-                guint i, n;
-
-                mm_bearer_ip_config_set_method (ipv6_config, MM_BEARER_IP_METHOD_STATIC);
+                ipv6addresscount > 0) {
 
                 /* IP address, pick the first one */
                 addr = g_inet_address_new_from_bytes ((guint8 *)&ipv6address[0]->ipv6_address, G_SOCKET_FAMILY_IPV6);
                 str = g_inet_address_to_string (addr);
                 mm_bearer_ip_config_set_address (ipv6_config, str);
                 g_free (str);
+                address_set = TRUE;
 
                 /* If the address is a link-local one, then SLAAC or DHCP must be used
-                 * to get the real prefix and address.  Change the method to DHCP to
-                 * indicate this to clients.
+                 * to get the real prefix and address.
+                 * FIXME: maybe the modem reported non-LL address in ipv6address[1] ?
                  */
                 if (g_inet_address_get_is_link_local (addr))
-                    mm_bearer_ip_config_set_method (ipv6_config, MM_BEARER_IP_METHOD_DHCP);
+                    address_set = FALSE;
 
                 g_object_unref (addr);
 
@@ -502,7 +505,14 @@ ip_configuration_query_ready (MbimDevice *device,
                     mm_bearer_ip_config_set_gateway (ipv6_config, str);
                     g_free (str);
                     g_object_unref (addr);
+                    gateway_set = TRUE;
                 }
+            }
+
+            if (ipv6configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_DNS &&
+                ipv6dnsservercount > 0) {
+                gchar **strarr;
+                guint i, n;
 
                 /* DNS */
                 strarr = g_new0 (gchar *, ipv6dnsservercount + 1);
@@ -514,12 +524,22 @@ ip_configuration_query_ready (MbimDevice *device,
                 }
                 mm_bearer_ip_config_set_dns (ipv6_config, (const gchar **)strarr);
                 g_strfreev (strarr);
-            } else
-                mm_bearer_ip_config_set_method (ipv6_config, MM_BEARER_IP_METHOD_DHCP);
+
+                dns_set = TRUE;
+            }
 
             /* MTU */
             if (ipv6configurationavailable & MBIM_IP_CONFIGURATION_AVAILABLE_FLAG_MTU)
                 mm_bearer_ip_config_set_mtu (ipv6_config, ipv6mtu);
+
+            /* Only use the static method if all basic properties are available,
+             * otherwise use DHCP to indicate the missing ones should be
+             * retrieved from SLAAC or DHCPv6.
+             */
+            if (address_set && gateway_set && dns_set)
+                mm_bearer_ip_config_set_method (ipv6_config, MM_BEARER_IP_METHOD_STATIC);
+            else
+                mm_bearer_ip_config_set_method (ipv6_config, MM_BEARER_IP_METHOD_DHCP);
         } else
             ipv6_config = NULL;