NFC: Send netlink events for secure elements additions and removals

When an NFC driver or host controller stack discovers a secure element,
it will call nfc_add_se(). In order for userspace applications to use
these secure elements, a netlink event will then be sent with the SE
index and its type. With that information userspace applications can
decide wether or not to enable SEs, through their indexes.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/uapi/linux/nfc.h

@@ -95,6 +95,8 @@ enum nfc_commands {
 	NFC_CMD_LLC_SDREQ,
 	NFC_EVENT_LLC_SDRES,
 	NFC_CMD_FW_UPLOAD,
+	NFC_EVENT_SE_ADDED,
+	NFC_EVENT_SE_REMOVED,
 /* private: internal use only */
 	__NFC_CMD_AFTER_LAST
 };
@@ -125,6 +127,8 @@ enum nfc_commands {
  * @NFC_ATTR_LLC_PARAM_MIUX: MIU eXtension parameter
  * @NFC_ATTR_SE: Available Secure Elements
  * @NFC_ATTR_FIRMWARE_NAME: Free format firmware version
+ * @NFC_ATTR_SE_INDEX: Secure element index
+ * @NFC_ATTR_SE_TYPE: Secure element type (UICC or EMBEDDED)
  */
 enum nfc_attrs {
 	NFC_ATTR_UNSPEC,
@@ -148,6 +152,8 @@ enum nfc_attrs {
 	NFC_ATTR_SE,
 	NFC_ATTR_LLC_SDP,
 	NFC_ATTR_FIRMWARE_NAME,
+	NFC_ATTR_SE_INDEX,
+	NFC_ATTR_SE_TYPE,
 /* private: internal use only */
 	__NFC_ATTR_AFTER_LAST
 };

net/nfc/core.c

@@ -763,6 +763,7 @@ EXPORT_SYMBOL(nfc_driver_failure);
 int nfc_add_se(struct nfc_dev *dev, u32 se_idx, u16 type)
 {
 	struct nfc_se *se, *n;
+	int rc;
 
 	pr_debug("%s se index %d\n", dev_name(&dev->dev), se_idx);
 
@@ -781,6 +782,14 @@ int nfc_add_se(struct nfc_dev *dev, u32 se_idx, u16 type)
 
 	list_add(&se->list, &dev->secure_elements);
 
+	rc = nfc_genl_se_added(dev, se_idx, type);
+	if (rc < 0) {
+		list_del(&se->list);
+		kfree(se);
+
+		return rc;
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL(nfc_add_se);
@@ -788,11 +797,16 @@ EXPORT_SYMBOL(nfc_add_se);
 int nfc_remove_se(struct nfc_dev *dev, u32 se_idx)
 {
 	struct nfc_se *se, *n;
+	int rc;
 
 	pr_debug("%s se index %d\n", dev_name(&dev->dev), se_idx);
 
 	list_for_each_entry_safe(se, n, &dev->secure_elements, list)
 		if (se->idx == se_idx) {
+			rc = nfc_genl_se_removed(dev, se_idx);
+			if (rc < 0)
+				return rc;
+
 			list_del(&se->list);
 			kfree(se);
 

net/nfc/netlink.c

@@ -426,6 +426,69 @@ free_msg:
 	return rc;
 }
 
+int nfc_genl_se_added(struct nfc_dev *dev, u32 se_idx, u16 type)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+			  NFC_EVENT_SE_ADDED);
+	if (!hdr)
+		goto free_msg;
+
+	if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx) ||
+	    nla_put_u32(msg, NFC_ATTR_SE_INDEX, se_idx) ||
+	    nla_put_u8(msg, NFC_ATTR_SE_TYPE, type))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return -EMSGSIZE;
+}
+
+int nfc_genl_se_removed(struct nfc_dev *dev, u32 se_idx)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+			  NFC_EVENT_SE_REMOVED);
+	if (!hdr)
+		goto free_msg;
+
+	if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx) ||
+	    nla_put_u32(msg, NFC_ATTR_SE_INDEX, se_idx))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return -EMSGSIZE;
+}
+
 static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
 				u32 portid, u32 seq,
 				struct netlink_callback *cb,

net/nfc/nfc.h

@@ -94,6 +94,9 @@ int nfc_genl_tm_deactivated(struct nfc_dev *dev);
 
 int nfc_genl_llc_send_sdres(struct nfc_dev *dev, struct hlist_head *sdres_list);
 
+int nfc_genl_se_added(struct nfc_dev *dev, u32 se_idx, u16 type);
+int nfc_genl_se_removed(struct nfc_dev *dev, u32 se_idx);
+
 struct nfc_dev *nfc_get_device(unsigned int idx);
 
 static inline void nfc_put_device(struct nfc_dev *dev)