1 files changed, 823 insertions, 0 deletions

diff --git a/net/nfc/llcp_commands.c b/net/nfc/llcp_commands.c
new file mode 100644
index 000000000..5b8754ae7
--- /dev/null
+++ b/net/nfc/llcp_commands.c
@@ -0,0 +1,823 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2011  Intel Corporation. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "llcp: %s: " fmt, __func__
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nfc.h>
+
+#include <net/nfc/nfc.h>
+
+#include "nfc.h"
+#include "llcp.h"
+
+static const u8 llcp_tlv_length[LLCP_TLV_MAX] = {
+	0,
+	1, /* VERSION */
+	2, /* MIUX */
+	2, /* WKS */
+	1, /* LTO */
+	1, /* RW */
+	0, /* SN */
+	1, /* OPT */
+	0, /* SDREQ */
+	2, /* SDRES */
+
+};
+
+static u8 llcp_tlv8(const u8 *tlv, u8 type)
+{
+	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
+		return 0;
+
+	return tlv[2];
+}
+
+static u16 llcp_tlv16(const u8 *tlv, u8 type)
+{
+	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
+		return 0;
+
+	return be16_to_cpu(*((__be16 *)(tlv + 2)));
+}
+
+
+static u8 llcp_tlv_version(const u8 *tlv)
+{
+	return llcp_tlv8(tlv, LLCP_TLV_VERSION);
+}
+
+static u16 llcp_tlv_miux(const u8 *tlv)
+{
+	return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7ff;
+}
+
+static u16 llcp_tlv_wks(const u8 *tlv)
+{
+	return llcp_tlv16(tlv, LLCP_TLV_WKS);
+}
+
+static u16 llcp_tlv_lto(const u8 *tlv)
+{
+	return llcp_tlv8(tlv, LLCP_TLV_LTO);
+}
+
+static u8 llcp_tlv_opt(const u8 *tlv)
+{
+	return llcp_tlv8(tlv, LLCP_TLV_OPT);
+}
+
+static u8 llcp_tlv_rw(const u8 *tlv)
+{
+	return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
+}
+
+u8 *nfc_llcp_build_tlv(u8 type, const u8 *value, u8 value_length, u8 *tlv_length)
+{
+	u8 *tlv, length;
+
+	pr_debug("type %d\n", type);
+
+	if (type >= LLCP_TLV_MAX)
+		return NULL;
+
+	length = llcp_tlv_length[type];
+	if (length == 0 && value_length == 0)
+		return NULL;
+	else if (length == 0)
+		length = value_length;
+
+	*tlv_length = 2 + length;
+	tlv = kzalloc(2 + length, GFP_KERNEL);
+	if (tlv == NULL)
+		return tlv;
+
+	tlv[0] = type;
+	tlv[1] = length;
+	memcpy(tlv + 2, value, length);
+
+	return tlv;
+}
+
+struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap)
+{
+	struct nfc_llcp_sdp_tlv *sdres;
+	u8 value[2];
+
+	sdres = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
+	if (sdres == NULL)
+		return NULL;
+
+	value[0] = tid;
+	value[1] = sap;
+
+	sdres->tlv = nfc_llcp_build_tlv(LLCP_TLV_SDRES, value, 2,
+					&sdres->tlv_len);
+	if (sdres->tlv == NULL) {
+		kfree(sdres);
+		return NULL;
+	}
+
+	sdres->tid = tid;
+	sdres->sap = sap;
+
+	INIT_HLIST_NODE(&sdres->node);
+
+	return sdres;
+}
+
+struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, const char *uri,
+						  size_t uri_len)
+{
+	struct nfc_llcp_sdp_tlv *sdreq;
+
+	pr_debug("uri: %s, len: %zu\n", uri, uri_len);
+
+	/* sdreq->tlv_len is u8, takes uri_len, + 3 for header, + 1 for NULL */
+	if (WARN_ON_ONCE(uri_len > U8_MAX - 4))
+		return NULL;
+
+	sdreq = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
+	if (sdreq == NULL)
+		return NULL;
+
+	sdreq->tlv_len = uri_len + 3;
+
+	if (uri[uri_len - 1] == 0)
+		sdreq->tlv_len--;
+
+	sdreq->tlv = kzalloc(sdreq->tlv_len + 1, GFP_KERNEL);
+	if (sdreq->tlv == NULL) {
+		kfree(sdreq);
+		return NULL;
+	}
+
+	sdreq->tlv[0] = LLCP_TLV_SDREQ;
+	sdreq->tlv[1] = sdreq->tlv_len - 2;
+	sdreq->tlv[2] = tid;
+
+	sdreq->tid = tid;
+	sdreq->uri = sdreq->tlv + 3;
+	memcpy(sdreq->uri, uri, uri_len);
+
+	sdreq->time = jiffies;
+
+	INIT_HLIST_NODE(&sdreq->node);
+
+	return sdreq;
+}
+
+void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp)
+{
+	kfree(sdp->tlv);
+	kfree(sdp);
+}
+
+void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head)
+{
+	struct nfc_llcp_sdp_tlv *sdp;
+	struct hlist_node *n;
+
+	hlist_for_each_entry_safe(sdp, n, head, node) {
+		hlist_del(&sdp->node);
+
+		nfc_llcp_free_sdp_tlv(sdp);
+	}
+}
+
+int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
+			  const u8 *tlv_array, u16 tlv_array_len)
+{
+	const u8 *tlv = tlv_array;
+	u8 type, length, offset = 0;
+
+	pr_debug("TLV array length %d\n", tlv_array_len);
+
+	if (local == NULL)
+		return -ENODEV;
+
+	while (offset < tlv_array_len) {
+		type = tlv[0];
+		length = tlv[1];
+
+		pr_debug("type 0x%x length %d\n", type, length);
+
+		switch (type) {
+		case LLCP_TLV_VERSION:
+			local->remote_version = llcp_tlv_version(tlv);
+			break;
+		case LLCP_TLV_MIUX:
+			local->remote_miu = llcp_tlv_miux(tlv) + 128;
+			break;
+		case LLCP_TLV_WKS:
+			local->remote_wks = llcp_tlv_wks(tlv);
+			break;
+		case LLCP_TLV_LTO:
+			local->remote_lto = llcp_tlv_lto(tlv) * 10;
+			break;
+		case LLCP_TLV_OPT:
+			local->remote_opt = llcp_tlv_opt(tlv);
+			break;
+		default:
+			pr_err("Invalid gt tlv value 0x%x\n", type);
+			break;
+		}
+
+		offset += length + 2;
+		tlv += length + 2;
+	}
+
+	pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x\n",
+		 local->remote_version, local->remote_miu,
+		 local->remote_lto, local->remote_opt,
+		 local->remote_wks);
+
+	return 0;
+}
+
+int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
+				  const u8 *tlv_array, u16 tlv_array_len)
+{
+	const u8 *tlv = tlv_array;
+	u8 type, length, offset = 0;
+
+	pr_debug("TLV array length %d\n", tlv_array_len);
+
+	if (sock == NULL)
+		return -ENOTCONN;
+
+	while (offset < tlv_array_len) {
+		type = tlv[0];
+		length = tlv[1];
+
+		pr_debug("type 0x%x length %d\n", type, length);
+
+		switch (type) {
+		case LLCP_TLV_MIUX:
+			sock->remote_miu = llcp_tlv_miux(tlv) + 128;
+			break;
+		case LLCP_TLV_RW:
+			sock->remote_rw = llcp_tlv_rw(tlv);
+			break;
+		case LLCP_TLV_SN:
+			break;
+		default:
+			pr_err("Invalid gt tlv value 0x%x\n", type);
+			break;
+		}
+
+		offset += length + 2;
+		tlv += length + 2;
+	}
+
+	pr_debug("sock %p rw %d miu %d\n", sock,
+		 sock->remote_rw, sock->remote_miu);
+
+	return 0;
+}
+
+static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
+				       u8 dsap, u8 ssap, u8 ptype)
+{
+	u8 header[2];
+
+	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
+
+	header[0] = (u8)((dsap << 2) | (ptype >> 2));
+	header[1] = (u8)((ptype << 6) | ssap);
+
+	pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
+
+	skb_put_data(pdu, header, LLCP_HEADER_SIZE);
+
+	return pdu;
+}
+
+static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, const u8 *tlv,
+				    u8 tlv_length)
+{
+	/* XXX Add an skb length check */
+
+	if (tlv == NULL)
+		return NULL;
+
+	skb_put_data(pdu, tlv, tlv_length);
+
+	return pdu;
+}
+
+static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
+					 u8 cmd, u16 size)
+{
+	struct sk_buff *skb;
+	int err;
+
+	if (sock->ssap == 0)
+		return NULL;
+
+	skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
+				 size + LLCP_HEADER_SIZE, &err);
+	if (skb == NULL) {
+		pr_err("Could not allocate PDU\n");
+		return NULL;
+	}
+
+	skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);
+
+	return skb;
+}
+
+int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
+{
+	struct sk_buff *skb;
+	struct nfc_dev *dev;
+	struct nfc_llcp_local *local;
+
+	pr_debug("Sending DISC\n");
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	dev = sock->dev;
+	if (dev == NULL)
+		return -ENODEV;
+
+	skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	return 0;
+}
+
+int nfc_llcp_send_symm(struct nfc_dev *dev)
+{
+	struct sk_buff *skb;
+	struct nfc_llcp_local *local;
+	u16 size = 0;
+	int err;
+
+	pr_debug("Sending SYMM\n");
+
+	local = nfc_llcp_find_local(dev);
+	if (local == NULL)
+		return -ENODEV;
+
+	size += LLCP_HEADER_SIZE;
+	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
+
+	skb = alloc_skb(size, GFP_KERNEL);
+	if (skb == NULL) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
+
+	skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
+
+	__net_timestamp(skb);
+
+	nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_TX);
+
+	err = nfc_data_exchange(dev, local->target_idx, skb,
+				 nfc_llcp_recv, local);
+out:
+	nfc_llcp_local_put(local);
+	return err;
+}
+
+int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
+{
+	struct nfc_llcp_local *local;
+	struct sk_buff *skb;
+	const u8 *service_name_tlv = NULL;
+	const u8 *miux_tlv = NULL;
+	const u8 *rw_tlv = NULL;
+	u8 service_name_tlv_length = 0;
+	u8 miux_tlv_length,  rw_tlv_length, rw;
+	int err;
+	u16 size = 0;
+	__be16 miux;
+
+	pr_debug("Sending CONNECT\n");
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	if (sock->service_name != NULL) {
+		service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
+						      sock->service_name,
+						      sock->service_name_len,
+						      &service_name_tlv_length);
+		if (!service_name_tlv) {
+			err = -ENOMEM;
+			goto error_tlv;
+		}
+		size += service_name_tlv_length;
+	}
+
+	/* If the socket parameters are not set, use the local ones */
+	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
+		local->miux : sock->miux;
+	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
+
+	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
+				      &miux_tlv_length);
+	if (!miux_tlv) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+	size += miux_tlv_length;
+
+	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
+	if (!rw_tlv) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+	size += rw_tlv_length;
+
+	pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
+
+	skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
+	if (skb == NULL) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+
+	llcp_add_tlv(skb, service_name_tlv, service_name_tlv_length);
+	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
+	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	err = 0;
+
+error_tlv:
+	if (err)
+		pr_err("error %d\n", err);
+
+	kfree(service_name_tlv);
+	kfree(miux_tlv);
+	kfree(rw_tlv);
+
+	return err;
+}
+
+int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
+{
+	struct nfc_llcp_local *local;
+	struct sk_buff *skb;
+	const u8 *miux_tlv = NULL;
+	const u8 *rw_tlv = NULL;
+	u8 miux_tlv_length, rw_tlv_length, rw;
+	int err;
+	u16 size = 0;
+	__be16 miux;
+
+	pr_debug("Sending CC\n");
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	/* If the socket parameters are not set, use the local ones */
+	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
+		local->miux : sock->miux;
+	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
+
+	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
+				      &miux_tlv_length);
+	if (!miux_tlv) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+	size += miux_tlv_length;
+
+	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
+	if (!rw_tlv) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+	size += rw_tlv_length;
+
+	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
+	if (skb == NULL) {
+		err = -ENOMEM;
+		goto error_tlv;
+	}
+
+	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
+	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	err = 0;
+
+error_tlv:
+	if (err)
+		pr_err("error %d\n", err);
+
+	kfree(miux_tlv);
+	kfree(rw_tlv);
+
+	return err;
+}
+
+static struct sk_buff *nfc_llcp_allocate_snl(struct nfc_llcp_local *local,
+					     size_t tlv_length)
+{
+	struct sk_buff *skb;
+	struct nfc_dev *dev;
+	u16 size = 0;
+
+	if (local == NULL)
+		return ERR_PTR(-ENODEV);
+
+	dev = local->dev;
+	if (dev == NULL)
+		return ERR_PTR(-ENODEV);
+
+	size += LLCP_HEADER_SIZE;
+	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
+	size += tlv_length;
+
+	skb = alloc_skb(size, GFP_KERNEL);
+	if (skb == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
+
+	skb = llcp_add_header(skb, LLCP_SAP_SDP, LLCP_SAP_SDP, LLCP_PDU_SNL);
+
+	return skb;
+}
+
+int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
+			    struct hlist_head *tlv_list, size_t tlvs_len)
+{
+	struct nfc_llcp_sdp_tlv *sdp;
+	struct hlist_node *n;
+	struct sk_buff *skb;
+
+	skb = nfc_llcp_allocate_snl(local, tlvs_len);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	hlist_for_each_entry_safe(sdp, n, tlv_list, node) {
+		skb_put_data(skb, sdp->tlv, sdp->tlv_len);
+
+		hlist_del(&sdp->node);
+
+		nfc_llcp_free_sdp_tlv(sdp);
+	}
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	return 0;
+}
+
+int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
+			    struct hlist_head *tlv_list, size_t tlvs_len)
+{
+	struct nfc_llcp_sdp_tlv *sdreq;
+	struct hlist_node *n;
+	struct sk_buff *skb;
+
+	skb = nfc_llcp_allocate_snl(local, tlvs_len);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	mutex_lock(&local->sdreq_lock);
+
+	if (hlist_empty(&local->pending_sdreqs))
+		mod_timer(&local->sdreq_timer,
+			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
+
+	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
+		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
+
+		skb_put_data(skb, sdreq->tlv, sdreq->tlv_len);
+
+		hlist_del(&sdreq->node);
+
+		hlist_add_head(&sdreq->node, &local->pending_sdreqs);
+	}
+
+	mutex_unlock(&local->sdreq_lock);
+
+	skb_queue_tail(&local->tx_queue, skb);
+
+	return 0;
+}
+
+int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
+{
+	struct sk_buff *skb;
+	struct nfc_dev *dev;
+	u16 size = 1; /* Reason code */
+
+	pr_debug("Sending DM reason 0x%x\n", reason);
+
+	if (local == NULL)
+		return -ENODEV;
+
+	dev = local->dev;
+	if (dev == NULL)
+		return -ENODEV;
+
+	size += LLCP_HEADER_SIZE;
+	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
+
+	skb = alloc_skb(size, GFP_KERNEL);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
+
+	skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);
+
+	skb_put_data(skb, &reason, 1);
+
+	skb_queue_head(&local->tx_queue, skb);
+
+	return 0;
+}
+
+int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
+			  struct msghdr *msg, size_t len)
+{
+	struct sk_buff *pdu;
+	struct sock *sk = &sock->sk;
+	struct nfc_llcp_local *local;
+	size_t frag_len = 0, remaining_len;
+	u8 *msg_data, *msg_ptr;
+	u16 remote_miu;
+
+	pr_debug("Send I frame len %zd\n", len);
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	/* Remote is ready but has not acknowledged our frames */
+	if((sock->remote_ready &&
+	    skb_queue_len(&sock->tx_pending_queue) >= sock->remote_rw &&
+	    skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
+		pr_err("Pending queue is full %d frames\n",
+		       skb_queue_len(&sock->tx_pending_queue));
+		return -ENOBUFS;
+	}
+
+	/* Remote is not ready and we've been queueing enough frames */
+	if ((!sock->remote_ready &&
+	     skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
+		pr_err("Tx queue is full %d frames\n",
+		       skb_queue_len(&sock->tx_queue));
+		return -ENOBUFS;
+	}
+
+	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
+	if (msg_data == NULL)
+		return -ENOMEM;
+
+	if (memcpy_from_msg(msg_data, msg, len)) {
+		kfree(msg_data);
+		return -EFAULT;
+	}
+
+	remaining_len = len;
+	msg_ptr = msg_data;
+
+	do {
+		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
+				LLCP_DEFAULT_MIU : sock->remote_miu;
+
+		frag_len = min_t(size_t, remote_miu, remaining_len);
+
+		pr_debug("Fragment %zd bytes remaining %zd",
+			 frag_len, remaining_len);
+
+		pdu = llcp_allocate_pdu(sock, LLCP_PDU_I,
+					frag_len + LLCP_SEQUENCE_SIZE);
+		if (pdu == NULL) {
+			kfree(msg_data);
+			return -ENOMEM;
+		}
+
+		skb_put(pdu, LLCP_SEQUENCE_SIZE);
+
+		if (likely(frag_len > 0))
+			skb_put_data(pdu, msg_ptr, frag_len);
+
+		skb_queue_tail(&sock->tx_queue, pdu);
+
+		lock_sock(sk);
+
+		nfc_llcp_queue_i_frames(sock);
+
+		release_sock(sk);
+
+		remaining_len -= frag_len;
+		msg_ptr += frag_len;
+	} while (remaining_len > 0);
+
+	kfree(msg_data);
+
+	return len;
+}
+
+int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
+			   struct msghdr *msg, size_t len)
+{
+	struct sk_buff *pdu;
+	struct nfc_llcp_local *local;
+	size_t frag_len = 0, remaining_len;
+	u8 *msg_ptr, *msg_data;
+	u16 remote_miu;
+	int err;
+
+	pr_debug("Send UI frame len %zd\n", len);
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
+	if (msg_data == NULL)
+		return -ENOMEM;
+
+	if (memcpy_from_msg(msg_data, msg, len)) {
+		kfree(msg_data);
+		return -EFAULT;
+	}
+
+	remaining_len = len;
+	msg_ptr = msg_data;
+
+	do {
+		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
+				local->remote_miu : sock->remote_miu;
+
+		frag_len = min_t(size_t, remote_miu, remaining_len);
+
+		pr_debug("Fragment %zd bytes remaining %zd",
+			 frag_len, remaining_len);
+
+		pdu = nfc_alloc_send_skb(sock->dev, &sock->sk, 0,
+					 frag_len + LLCP_HEADER_SIZE, &err);
+		if (pdu == NULL) {
+			pr_err("Could not allocate PDU (error=%d)\n", err);
+			len -= remaining_len;
+			if (len == 0)
+				len = err;
+			break;
+		}
+
+		pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);
+
+		if (likely(frag_len > 0))
+			skb_put_data(pdu, msg_ptr, frag_len);
+
+		/* No need to check for the peer RW for UI frames */
+		skb_queue_tail(&local->tx_queue, pdu);
+
+		remaining_len -= frag_len;
+		msg_ptr += frag_len;
+	} while (remaining_len > 0);
+
+	kfree(msg_data);
+
+	return len;
+}
+
+int nfc_llcp_send_rr(struct nfc_llcp_sock *sock)
+{
+	struct sk_buff *skb;
+	struct nfc_llcp_local *local;
+
+	pr_debug("Send rr nr %d\n", sock->recv_n);
+
+	local = sock->local;
+	if (local == NULL)
+		return -ENODEV;
+
+	skb = llcp_allocate_pdu(sock, LLCP_PDU_RR, LLCP_SEQUENCE_SIZE);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	skb_put(skb, LLCP_SEQUENCE_SIZE);
+
+	skb->data[2] = sock->recv_n;
+
+	skb_queue_head(&local->tx_queue, skb);
+
+	return 0;
+}