NFC: Extend netlink interface for LTO, RW, and MIUX parameters support

NFC_CMD_LLC_GET_PARAMS: request LTO, RW, and MIUX parameters for a device

NFC_CMD_LLC_SET_PARAMS: set one or more of LTO, RW, and MIUX parameters for
a device. LTO must be set before the link is up otherwise -EINPROGRESS is
returned. RW and MIUX can be set at anytime and will be passed in subsequent
CONNECT and CC messages. If one of the passed parameters is wrong none is
set and -EINVAL is returned.

Signed-off-by: Thierry Escande <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

include/uapi/linux/nfc.h

···
  *      target mode.
  * @NFC_EVENT_DEVICE_DEACTIVATED: event emitted when the adapter is deactivated
  *      from target mode.
+ * @NFC_CMD_LLC_GET_PARAMS: request LTO, RW, and MIUX parameters for a device
+ * @NFC_CMD_LLC_SET_PARAMS: set one or more of LTO, RW, and MIUX parameters for
+ *	a device. LTO must be set before the link is up otherwise -EINPROGRESS
+ *	is returned. RW and MIUX can be set at anytime and will be passed in
+ *	subsequent CONNECT and CC messages.
+ *	If one of the passed parameters is wrong none is set and -EINVAL is
+ *	returned.
  */
 enum nfc_commands {
 	NFC_CMD_UNSPEC,
···
 	NFC_EVENT_TARGET_LOST,
 	NFC_EVENT_TM_ACTIVATED,
 	NFC_EVENT_TM_DEACTIVATED,
+	NFC_CMD_LLC_GET_PARAMS,
+	NFC_CMD_LLC_SET_PARAMS,
 /* private: internal use only */
 	__NFC_CMD_AFTER_LAST
 };
···
  * @NFC_ATTR_RF_MODE: Initiator or target
  * @NFC_ATTR_IM_PROTOCOLS: Initiator mode protocols to poll for
  * @NFC_ATTR_TM_PROTOCOLS: Target mode protocols to listen for
+ * @NFC_ATTR_LLC_PARAM_LTO: Link TimeOut parameter
+ * @NFC_ATTR_LLC_PARAM_RW: Receive Window size parameter
+ * @NFC_ATTR_LLC_PARAM_MIUX: MIU eXtension parameter
  */
 enum nfc_attrs {
 	NFC_ATTR_UNSPEC,
···
 	NFC_ATTR_DEVICE_POWERED,
 	NFC_ATTR_IM_PROTOCOLS,
 	NFC_ATTR_TM_PROTOCOLS,
+	NFC_ATTR_LLC_PARAM_LTO,
+	NFC_ATTR_LLC_PARAM_RW,
+	NFC_ATTR_LLC_PARAM_MIUX,
 /* private: internal use only */
 	__NFC_ATTR_AFTER_LAST
 };

net/nfc/llcp/commands.c

···
 	struct sk_buff *skb;
 	u8 *service_name_tlv = NULL, service_name_tlv_length;
 	u8 *miux_tlv = NULL, miux_tlv_length;
-	u8 *rw_tlv = NULL, rw_tlv_length, rw;
-	__be16 miux;
+	u8 *rw_tlv = NULL, rw_tlv_length;
 	int err;
 	u16 size = 0;
 
···
 		size += service_name_tlv_length;
 	}
 
-	miux = cpu_to_be16(LLCP_MAX_MIUX);
-	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
+	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
 				      &miux_tlv_length);
 	size += miux_tlv_length;
 
-	rw = LLCP_MAX_RW;
-	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
+	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &local->rw, 0, &rw_tlv_length);
 	size += rw_tlv_length;
 
 	pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
···
 	struct nfc_llcp_local *local;
 	struct sk_buff *skb;
 	u8 *miux_tlv = NULL, miux_tlv_length;
-	u8 *rw_tlv = NULL, rw_tlv_length, rw;
-	__be16 miux;
+	u8 *rw_tlv = NULL, rw_tlv_length;
 	int err;
 	u16 size = 0;
 
···
 	if (local == NULL)
 		return -ENODEV;
 
-	miux = cpu_to_be16(LLCP_MAX_MIUX);
-	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
+	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
 				      &miux_tlv_length);
 	size += miux_tlv_length;
 
-	rw = LLCP_MAX_RW;
-	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
+	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &local->rw, 0, &rw_tlv_length);
 	size += rw_tlv_length;
 
 	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);

net/nfc/llcp/llcp.c

···
 static int nfc_llcp_build_gb(struct nfc_llcp_local *local)
 {
 	u8 *gb_cur, *version_tlv, version, version_length;
-	u8 *lto_tlv, lto, lto_length;
+	u8 *lto_tlv, lto_length;
 	u8 *wks_tlv, wks_length;
 	u8 *miux_tlv, miux_length;
-	__be16 miux;
 	u8 gb_len = 0;
 	int ret = 0;
 
···
 					 1, &version_length);
 	gb_len += version_length;
 
-	/* 1500 ms */
-	lto = 150;
-	lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &lto, 1, &lto_length);
+	lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &local->lto, 1, &lto_length);
 	gb_len += lto_length;
 
 	pr_debug("Local wks 0x%lx\n", local->local_wks);
···
 				     &wks_length);
 	gb_len += wks_length;
 
-	miux = cpu_to_be16(LLCP_MAX_MIUX);
-	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
+	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
 				      &miux_length);
 	gb_len += miux_length;
 
···
 	rwlock_init(&local->sockets.lock);
 	rwlock_init(&local->connecting_sockets.lock);
 	rwlock_init(&local->raw_sockets.lock);
+
+	local->lto = 150; /* 1500 ms */
+	local->rw = LLCP_MAX_RW;
+	local->miux = cpu_to_be16(LLCP_MAX_MIUX);
 
 	nfc_llcp_build_gb(local);
 

net/nfc/llcp/llcp.h

···
 	u32 target_idx;
 	u8 rf_mode;
 	u8 comm_mode;
+	u8 lto;
+	u8 rw;
+	__be16 miux;
 	unsigned long local_wks;      /* Well known services */
 	unsigned long local_sdp;      /* Local services  */
 	unsigned long local_sap; /* Local SAPs, not available for discovery */

net/nfc/netlink.c

···
 
 #include "nfc.h"
 
+#include "llcp/llcp.h"
+
 static struct genl_multicast_group nfc_genl_event_mcgrp = {
 	.name = NFC_GENL_MCAST_EVENT_NAME,
 };
···
 	return rc;
 }
 
+static int nfc_genl_send_params(struct sk_buff *msg,
+				struct nfc_llcp_local *local,
+				u32 portid, u32 seq)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(msg, portid, seq, &nfc_genl_family, 0,
+			  NFC_CMD_LLC_GET_PARAMS);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, local->dev->idx) ||
+	    nla_put_u8(msg, NFC_ATTR_LLC_PARAM_LTO, local->lto) ||
+	    nla_put_u8(msg, NFC_ATTR_LLC_PARAM_RW, local->rw) ||
+	    nla_put_u16(msg, NFC_ATTR_LLC_PARAM_MIUX, be16_to_cpu(local->miux)))
+		goto nla_put_failure;
+
+	return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static int nfc_genl_llc_get_params(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nfc_dev *dev;
+	struct nfc_llcp_local *local;
+	int rc = 0;
+	struct sk_buff *msg = NULL;
+	u32 idx;
+
+	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+		return -EINVAL;
+
+	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+	dev = nfc_get_device(idx);
+	if (!dev)
+		return -ENODEV;
+
+	device_lock(&dev->dev);
+
+	local = nfc_llcp_find_local(dev);
+	if (!local) {
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg) {
+		rc = -ENOMEM;
+		goto exit;
+	}
+
+	rc = nfc_genl_send_params(msg, local, info->snd_portid, info->snd_seq);
+
+exit:
+	device_unlock(&dev->dev);
+
+	nfc_put_device(dev);
+
+	if (rc < 0) {
+		if (msg)
+			nlmsg_free(msg);
+
+		return rc;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+
+static int nfc_genl_llc_set_params(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nfc_dev *dev;
+	struct nfc_llcp_local *local;
+	u8 rw = 0;
+	u16 miux = 0;
+	u32 idx;
+	int rc = 0;
+
+	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+	    (!info->attrs[NFC_ATTR_LLC_PARAM_LTO] &&
+	     !info->attrs[NFC_ATTR_LLC_PARAM_RW] &&
+	     !info->attrs[NFC_ATTR_LLC_PARAM_MIUX]))
+		return -EINVAL;
+
+	if (info->attrs[NFC_ATTR_LLC_PARAM_RW]) {
+		rw = nla_get_u8(info->attrs[NFC_ATTR_LLC_PARAM_RW]);
+
+		if (rw > LLCP_MAX_RW)
+			return -EINVAL;
+	}
+
+	if (info->attrs[NFC_ATTR_LLC_PARAM_MIUX]) {
+		miux = nla_get_u16(info->attrs[NFC_ATTR_LLC_PARAM_MIUX]);
+
+		if (miux > LLCP_MAX_MIUX)
+			return -EINVAL;
+	}
+
+	idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+	dev = nfc_get_device(idx);
+	if (!dev)
+		return -ENODEV;
+
+	device_lock(&dev->dev);
+
+	local = nfc_llcp_find_local(dev);
+	if (!local) {
+		nfc_put_device(dev);
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	if (info->attrs[NFC_ATTR_LLC_PARAM_LTO]) {
+		if (dev->dep_link_up) {
+			rc = -EINPROGRESS;
+			goto exit;
+		}
+
+		local->lto = nla_get_u8(info->attrs[NFC_ATTR_LLC_PARAM_LTO]);
+	}
+
+	if (info->attrs[NFC_ATTR_LLC_PARAM_RW])
+		local->rw = rw;
+
+	if (info->attrs[NFC_ATTR_LLC_PARAM_MIUX])
+		local->miux = cpu_to_be16(miux);
+
+exit:
+	device_unlock(&dev->dev);
+
+	nfc_put_device(dev);
+
+	return rc;
+}
+
 static struct genl_ops nfc_genl_ops[] = {
 	{
 		.cmd = NFC_CMD_GET_DEVICE,
···
 		.cmd = NFC_CMD_GET_TARGET,
 		.dumpit = nfc_genl_dump_targets,
 		.done = nfc_genl_dump_targets_done,
+		.policy = nfc_genl_policy,
+	},
+	{
+		.cmd = NFC_CMD_LLC_GET_PARAMS,
+		.doit = nfc_genl_llc_get_params,
+		.policy = nfc_genl_policy,
+	},
+	{
+		.cmd = NFC_CMD_LLC_SET_PARAMS,
+		.doit = nfc_genl_llc_set_params,
 		.policy = nfc_genl_policy,
 	},
 };

net/nfc/nfc.h

···
 int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len);
 u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len);
 int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb);
+struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev);
 int __init nfc_llcp_init(void);
 void nfc_llcp_exit(void);
 
···
 					 struct sk_buff *skb)
 {
 	return 0;
+}
+
+static inline struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
+{
+	return NULL;
 }
 
 static inline int nfc_llcp_init(void)