net: rmnet_data: Add support for user defined device name prefix

Run-time user space components can now specify virtual network device
name prefix at device creation. This will be used to support legacy
data services.

CRs-Fixed: 555507
Change-Id: Id34c2761f2060e66b05c521304d5151620ba5665
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>

6 files changed, 132 insertions, 9 deletions

diff --git a/include/uapi/linux/rmnet_data.h b/include/uapi/linux/rmnet_data.h
index b8dbf907c8b3..bcff313a95c0 100644
--- a/include/uapi/linux/rmnet_data.h
+++ b/include/uapi/linux/rmnet_data.h
@@ -165,6 +165,23 @@ enum rmnet_netlink_message_types_e {
 	RMNET_NETLINK_NEW_VND,
 
 	/*
+	 * RMNET_NETLINK_NEW_VND_WITH_PREFIX - Creates a new virtual network
+	 *                                     device node with the specified
+	 *                                     prefix for the device name
+	 * Args: int32_t node number
+	 *       char[] vnd_name - Use as prefix
+	 * Returns: status code
+	 */
+	RMNET_NETLINK_NEW_VND_WITH_PREFIX,
+
+	/*
+	 * RMNET_NETLINK_GET_VND_NAME - Gets the string name of a VND from ID
+	 * Args: int32_t node number
+	 * Returns: char[] vnd_name
+	 */
+	RMNET_NETLINK_GET_VND_NAME,
+
+	/*
 	 * RMNET_NETLINK_FREE_VND - Removes virtual network device node
 	 * Args: int32_t node number
 	 * Returns: status code
diff --git a/net/rmnet_data/rmnet_data_config.c b/net/rmnet_data/rmnet_data_config.c
index caa6cfb516c7..e7a92696499c 100644
--- a/net/rmnet_data/rmnet_data_config.c
+++ b/net/rmnet_data/rmnet_data_config.c
@@ -237,7 +237,7 @@ static void _rmnet_netlink_unassociate_network_device
 	resp_rmnet->return_code = rmnet_unassociate_network_device(dev);
 }
 
-static inline void _rmnet_netlink_get_link_egress_data_format
+static void _rmnet_netlink_get_link_egress_data_format
 					(struct rmnet_nl_msg_s *rmnet_header,
 					 struct rmnet_nl_msg_s *resp_rmnet)
 {
@@ -267,7 +267,7 @@ static inline void _rmnet_netlink_get_link_egress_data_format
 	resp_rmnet->data_format.agg_size  = config->egress_agg_size;
 }
 
-static inline void _rmnet_netlink_get_link_ingress_data_format
+static void _rmnet_netlink_get_link_ingress_data_format
 					(struct rmnet_nl_msg_s *rmnet_header,
 					 struct rmnet_nl_msg_s *resp_rmnet)
 {
@@ -295,6 +295,27 @@ static inline void _rmnet_netlink_get_link_ingress_data_format
 	resp_rmnet->data_format.flags = config->ingress_data_format;
 }
 
+static void _rmnet_netlink_get_vnd_name
+					(struct rmnet_nl_msg_s *rmnet_header,
+					 struct rmnet_nl_msg_s *resp_rmnet)
+{
+	int r;
+	_RMNET_NETLINK_NULL_CHECKS();
+	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
+
+	r = rmnet_vnd_get_name(rmnet_header->vnd.id, resp_rmnet->vnd.vnd_name,
+			       RMNET_MAX_STR_LEN);
+
+	if (r != 0) {
+		resp_rmnet->return_code = RMNET_CONFIG_INVALID_REQUEST;
+		return;
+	}
+
+	/* Begin Data */
+	resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNDATA;
+	resp_rmnet->arg_length = RMNET_NL_MSG_SIZE(vnd);
+}
+
 /**
  * rmnet_config_netlink_msg_handler() - Netlink message handler callback
  * @skb:      Packet containing netlink messages
@@ -386,6 +407,17 @@ void rmnet_config_netlink_msg_handler(struct sk_buff *skb)
 					 rmnet_create_vnd(rmnet_header->vnd.id);
 		break;
 
+	case RMNET_NETLINK_NEW_VND_WITH_PREFIX:
+		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
+		resp_rmnet->return_code = rmnet_create_vnd_prefix(
+						rmnet_header->vnd.id,
+						rmnet_header->vnd.vnd_name);
+		break;
+
+	case RMNET_NETLINK_GET_VND_NAME:
+		_rmnet_netlink_get_vnd_name(rmnet_header, resp_rmnet);
+		break;
+
 	default:
 		resp_rmnet->crd = RMNET_NETLINK_MSG_RETURNCODE;
 		resp_rmnet->return_code = RMNET_CONFIG_UNKNOWN_MESSAGE;
@@ -669,5 +701,21 @@ int rmnet_create_vnd(int id)
 	struct net_device *dev;
 	ASSERT_RTNL();
 	LOGL("%s(%d);", __func__, id);
-	return rmnet_vnd_create_dev(id, &dev);
+	return rmnet_vnd_create_dev(id, &dev, NULL);
+}
+
+/**
+ * rmnet_create_vnd() - Create virtual network device node
+ * @id:       RmNet virtual device node id
+ * @prefix:   String prefix for device name
+ *
+ * Return:
+ *      - result of rmnet_vnd_create_dev()
+ */
+int rmnet_create_vnd_prefix(int id, const char *prefix)
+{
+	struct net_device *dev;
+	ASSERT_RTNL();
+	LOGL("%s(%d, \"%s\");", __func__, id, prefix);
+	return rmnet_vnd_create_dev(id, &dev, prefix);
 }
diff --git a/net/rmnet_data/rmnet_data_config.h b/net/rmnet_data/rmnet_data_config.h
index 2f8efc59f45d..2eac471fc83c 100644
--- a/net/rmnet_data/rmnet_data_config.h
+++ b/net/rmnet_data/rmnet_data_config.h
@@ -65,5 +65,6 @@ int rmnet_set_logical_endpoint_config(struct net_device *dev,
 				      struct net_device *egress_dev);
 void rmnet_config_netlink_msg_handler (struct sk_buff *skb);
 int rmnet_create_vnd(int id);
+int rmnet_create_vnd_prefix(int id, const char *name);
 
 #endif /* _RMNET_DATA_CONFIG_H_ */
diff --git a/net/rmnet_data/rmnet_data_private.h b/net/rmnet_data/rmnet_data_private.h
index ae253b9db5fc..cc4f2e4a27ca 100644
--- a/net/rmnet_data/rmnet_data_private.h
+++ b/net/rmnet_data/rmnet_data_private.h
@@ -17,7 +17,7 @@
 #define RMNET_DATA_MAX_VND              32
 #define RMNET_DATA_MAX_PACKET_SIZE      16384
 #define RMNET_DATA_DFLT_PACKET_SIZE     1500
-#define RMNET_DATA_DEV_NAME_STR         "rmnet_data%d"
+#define RMNET_DATA_DEV_NAME_STR         "rmnet_data"
 #define RMNET_DATA_NEEDED_HEADROOM      16
 #define RMNET_ETHERNET_HEADER_LENGTH    14
 
diff --git a/net/rmnet_data/rmnet_data_vnd.c b/net/rmnet_data/rmnet_data_vnd.c
index f304de49404d..dc59e8db55fa 100644
--- a/net/rmnet_data/rmnet_data_vnd.c
+++ b/net/rmnet_data/rmnet_data_vnd.c
@@ -360,29 +360,45 @@ int rmnet_vnd_init(void)
  * rmnet_vnd_create_dev() - Create a new virtual network device node.
  * @id:         Virtual device node id
  * @new_device: Pointer to newly created device node
+ * @prefix:     Device name prefix
  *
  * Allocates structures for new virtual network devices. Sets the name of the
  * new device and registers it with the network stack. Device will appear in
- * ifconfig list after this is called.
+ * ifconfig list after this is called. If the prefix is null, then
+ * RMNET_DATA_DEV_NAME_STR will be assumed.
  *
  * Return:
  *      - 0 if successful
  *      - -EINVAL if id is out of range, or id already in use
  *      - -EINVAL if net_device allocation failed
+ *      - -EINVAL if prefix does not fit in buffer
  *      - return code of register_netdevice() on other errors
  */
-int rmnet_vnd_create_dev(int id, struct net_device **new_device)
+int rmnet_vnd_create_dev(int id, struct net_device **new_device,
+			 const char *prefix)
 {
 	struct net_device *dev;
-	int rc = 0;
+	char dev_prefix[IFNAMSIZ];
+	int p, rc = 0;
 
 	if (id < 0 || id > RMNET_DATA_MAX_VND || rmnet_devices[id] != 0) {
 		*new_device = 0;
 		return -EINVAL;
 	}
 
+	if (!prefix)
+		p = scnprintf(dev_prefix, IFNAMSIZ, "%s%%d",
+			  RMNET_DATA_DEV_NAME_STR);
+	else
+		p = scnprintf(dev_prefix, IFNAMSIZ, "%s%%d",
+			  prefix);
+	if (p >= (IFNAMSIZ-1)) {
+		LOGE("%s(): Specified prefix longer than IFNAMSIZ", __func__);
+		return -EINVAL;
+	}
+
 	dev = alloc_netdev(sizeof(struct rmnet_vnd_private_s),
-			   RMNET_DATA_DEV_NAME_STR,
+			   dev_prefix,
 			   rmnet_vnd_setup);
 	if (!dev) {
 		LOGE("%s(): Failed to to allocate netdev for id %d",
@@ -407,6 +423,45 @@ int rmnet_vnd_create_dev(int id, struct net_device **new_device)
 }
 
 /**
+ * rmnet_vnd_get_name() - Gets the string name of a VND based on ID
+ * @id:         Virtual device node id
+ * @name:       Buffer to store name of virtual device node
+ * @name_len:   Length of name buffer
+ *
+ * Copies the name of the virtual device node into the users buffer. Will throw
+ * an error if the buffer is null, or too small to hold the device name.
+ *
+ * Return:
+ *      - 0 if successful
+ *      - -EINVAL if name is null
+ *      - -EINVAL if id is invalid or not in range
+ *      - -EINVAL if name is too small to hold things
+ */
+int rmnet_vnd_get_name(int id, char *name, int name_len)
+{
+	int p;
+
+	if (!name) {
+		LOGM("%s(): Bad arguments; name buffer null", __func__);
+		return -EINVAL;
+	}
+
+	if ((id < 0) || (id >= RMNET_DATA_MAX_VND) || !rmnet_devices[id]) {
+		LOGM("%s(): Invalid id [%d]", __func__, id);
+		return -EINVAL;
+	}
+
+	p = strlcpy(name, rmnet_devices[id]->name, name_len);
+	if (p >= name_len) {
+		LOGM("%s(): Buffer to small to fit device name", __func__);
+		return -EINVAL;
+	}
+	LOGL("%s(): Found mapping [%d]->\"%s\"", __func__, id, name);
+
+	return 0;
+}
+
+/**
  * rmnet_vnd_is_vnd() - Determine if net_device is RmNet owned virtual devices
  * @dev:        Network device to test
  *
diff --git a/net/rmnet_data/rmnet_data_vnd.h b/net/rmnet_data/rmnet_data_vnd.h
index a916b2534a6d..2e1ff1c5d87b 100644
--- a/net/rmnet_data/rmnet_data_vnd.h
+++ b/net/rmnet_data/rmnet_data_vnd.h
@@ -23,7 +23,9 @@ int rmnet_vnd_get_flow_mapping(struct net_device *dev,
 			       unsigned int map_flow_id,
 			       unsigned int *flow_map);
 struct rmnet_logical_ep_conf_s *rmnet_vnd_get_le_config(struct net_device *dev);
-int rmnet_vnd_create_dev(int id, struct net_device **new_device);
+int rmnet_vnd_get_name(int id, char *name, int name_len);
+int rmnet_vnd_create_dev(int id, struct net_device **new_device,
+			 const char *prefix);
 int rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev);
 int rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev);
 int rmnet_vnd_is_vnd(struct net_device *dev);