NFC: add the NFC socket raw protocol

This socket protocol is used to perform data exchange with NFC
targets.

Signed-off-by: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Signed-off-by: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 376 insertions, 1 deletions

diff --git a/net/nfc/Makefile b/net/nfc/Makefile
index e081fdb86a59..16250c353851 100644
--- a/net/nfc/Makefile
+++ b/net/nfc/Makefile
@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_NFC) += nfc.o
 
-nfc-objs := core.o netlink.o af_nfc.o
+nfc-objs := core.o netlink.o af_nfc.o rawsock.o
diff --git a/net/nfc/core.c b/net/nfc/core.c
index e804dc50f42f..b6fd4e1f2057 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -432,6 +432,10 @@ static int __init nfc_init(void)
         /* the first generation must not be 0 */
         nfc_devlist_generation = 1;
 
+        rc = rawsock_init();
+        if (rc)
+                goto err_rawsock;
+
         rc = af_nfc_init();
         if (rc)
                 goto err_af_nfc;
@@ -439,6 +443,8 @@ static int __init nfc_init(void)
         return 0;
 
 err_af_nfc:
+        rawsock_exit();
+err_rawsock:
         nfc_genl_exit();
 err_genl:
         class_unregister(&nfc_class);
@@ -448,6 +454,7 @@ err_genl:
 static void __exit nfc_exit(void)
 {
         af_nfc_exit();
+        rawsock_exit();
         nfc_genl_exit();
         class_unregister(&nfc_class);
 }
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
index 8335f4de8f4f..aaf9832298f3 100644
--- a/net/nfc/nfc.h
+++ b/net/nfc/nfc.h
@@ -42,6 +42,20 @@ struct nfc_protocol {
                         const struct nfc_protocol *nfc_proto);
 };
 
+struct nfc_rawsock {
+        struct sock sk;
+        struct nfc_dev *dev;
+        u32 target_idx;
+        struct work_struct tx_work;
+        bool tx_work_scheduled;
+};
+#define nfc_rawsock(sk) ((struct nfc_rawsock *) sk)
+#define to_rawsock_sk(_tx_work) \
+        ((struct sock *) container_of(_tx_work, struct nfc_rawsock, tx_work))
+
+int __init rawsock_init(void);
+void rawsock_exit(void);
+
 int __init af_nfc_init(void);
 void af_nfc_exit(void);
 int nfc_proto_register(const struct nfc_protocol *nfc_proto);
diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c
new file mode 100644
index 000000000000..52de84a55115
--- /dev/null
+++ b/net/nfc/rawsock.c
@@ -0,0 +1,354 @@
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <net/tcp_states.h>
+#include <linux/nfc.h>
+
+#include "nfc.h"
+
+static void rawsock_write_queue_purge(struct sock *sk)
+{
+        nfc_dbg("sk=%p", sk);
+
+        spin_lock_bh(&sk->sk_write_queue.lock);
+        __skb_queue_purge(&sk->sk_write_queue);
+        nfc_rawsock(sk)->tx_work_scheduled = false;
+        spin_unlock_bh(&sk->sk_write_queue.lock);
+}
+
+static void rawsock_report_error(struct sock *sk, int err)
+{
+        nfc_dbg("sk=%p err=%d", sk, err);
+
+        sk->sk_shutdown = SHUTDOWN_MASK;
+        sk->sk_err = -err;
+        sk->sk_error_report(sk);
+
+        rawsock_write_queue_purge(sk);
+}
+
+static int rawsock_release(struct socket *sock)
+{
+        struct sock *sk = sock->sk;
+
+        nfc_dbg("sock=%p", sock);
+
+        sock_orphan(sk);
+        sock_put(sk);
+
+        return 0;
+}
+
+static int rawsock_connect(struct socket *sock, struct sockaddr *_addr,
+                                                        int len, int flags)
+{
+        struct sock *sk = sock->sk;
+        struct sockaddr_nfc *addr = (struct sockaddr_nfc *)_addr;
+        struct nfc_dev *dev;
+        int rc = 0;
+
+        nfc_dbg("sock=%p sk=%p flags=%d", sock, sk, flags);
+
+        if (!addr || len < sizeof(struct sockaddr_nfc) ||
+                addr->sa_family != AF_NFC)
+                return -EINVAL;
+
+        nfc_dbg("addr dev_idx=%u target_idx=%u protocol=%u", addr->dev_idx,
+                                        addr->target_idx, addr->nfc_protocol);
+
+        lock_sock(sk);
+
+        if (sock->state == SS_CONNECTED) {
+                rc = -EISCONN;
+                goto error;
+        }
+
+        dev = nfc_get_device(addr->dev_idx);
+        if (!dev) {
+                rc = -ENODEV;
+                goto error;
+        }
+
+        if (addr->target_idx > dev->target_idx - 1 ||
+                addr->target_idx < dev->target_idx - dev->n_targets) {
+                rc = -EINVAL;
+                goto error;
+        }
+
+        if (addr->target_idx > dev->target_idx - 1 ||
+                addr->target_idx < dev->target_idx - dev->n_targets) {
+                rc = -EINVAL;
+                goto error;
+        }
+
+        rc = nfc_activate_target(dev, addr->target_idx, addr->nfc_protocol);
+        if (rc)
+                goto put_dev;
+
+        nfc_rawsock(sk)->dev = dev;
+        nfc_rawsock(sk)->target_idx = addr->target_idx;
+        sock->state = SS_CONNECTED;
+        sk->sk_state = TCP_ESTABLISHED;
+        sk->sk_state_change(sk);
+
+        release_sock(sk);
+        return 0;
+
+put_dev:
+        nfc_put_device(dev);
+error:
+        release_sock(sk);
+        return rc;
+}
+
+static int rawsock_add_header(struct sk_buff *skb)
+{
+
+        if (skb_cow_head(skb, 1))
+                return -ENOMEM;
+
+        *skb_push(skb, 1) = 0;
+
+        return 0;
+}
+
+static void rawsock_data_exchange_complete(void *context, struct sk_buff *skb,
+                                                                int err)
+{
+        struct sock *sk = (struct sock *) context;
+
+        BUG_ON(in_irq());
+
+        nfc_dbg("sk=%p err=%d", sk, err);
+
+        if (err)
+                goto error;
+
+        err = rawsock_add_header(skb);
+        if (err)
+                goto error;
+
+        err = sock_queue_rcv_skb(sk, skb);
+        if (err)
+                goto error;
+
+        spin_lock_bh(&sk->sk_write_queue.lock);
+        if (!skb_queue_empty(&sk->sk_write_queue))
+                schedule_work(&nfc_rawsock(sk)->tx_work);
+        else
+                nfc_rawsock(sk)->tx_work_scheduled = false;
+        spin_unlock_bh(&sk->sk_write_queue.lock);
+
+        sock_put(sk);
+        return;
+
+error:
+        rawsock_report_error(sk, err);
+        sock_put(sk);
+}
+
+static void rawsock_tx_work(struct work_struct *work)
+{
+        struct sock *sk = to_rawsock_sk(work);
+        struct nfc_dev *dev = nfc_rawsock(sk)->dev;
+        u32 target_idx = nfc_rawsock(sk)->target_idx;
+        struct sk_buff *skb;
+        int rc;
+
+        nfc_dbg("sk=%p target_idx=%u", sk, target_idx);
+
+        if (sk->sk_shutdown & SEND_SHUTDOWN) {
+                rawsock_write_queue_purge(sk);
+                return;
+        }
+
+        skb = skb_dequeue(&sk->sk_write_queue);
+
+        sock_hold(sk);
+        rc = nfc_data_exchange(dev, target_idx, skb,
+                                rawsock_data_exchange_complete, sk);
+        if (rc) {
+                rawsock_report_error(sk, rc);
+                sock_put(sk);
+        }
+}
+
+static int rawsock_sendmsg(struct kiocb *iocb, struct socket *sock,
+                                        struct msghdr *msg, size_t len)
+{
+        struct sock *sk = sock->sk;
+        struct sk_buff *skb;
+        int rc;
+
+        nfc_dbg("sock=%p sk=%p len=%zu", sock, sk, len);
+
+        if (msg->msg_namelen)
+                return -EOPNOTSUPP;
+
+        if (sock->state != SS_CONNECTED)
+                return -ENOTCONN;
+
+        skb = sock_alloc_send_skb(sk, len, msg->msg_flags & MSG_DONTWAIT,
+                                                                        &rc);
+        if (!skb)
+                return rc;
+
+        rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
+        if (rc < 0) {
+                kfree_skb(skb);
+                return rc;
+        }
+
+        spin_lock_bh(&sk->sk_write_queue.lock);
+        __skb_queue_tail(&sk->sk_write_queue, skb);
+        if (!nfc_rawsock(sk)->tx_work_scheduled) {
+                schedule_work(&nfc_rawsock(sk)->tx_work);
+                nfc_rawsock(sk)->tx_work_scheduled = true;
+        }
+        spin_unlock_bh(&sk->sk_write_queue.lock);
+
+        return len;
+}
+
+static int rawsock_recvmsg(struct kiocb *iocb, struct socket *sock,
+                                struct msghdr *msg, size_t len, int flags)
+{
+        int noblock = flags & MSG_DONTWAIT;
+        struct sock *sk = sock->sk;
+        struct sk_buff *skb;
+        int copied;
+        int rc;
+
+        nfc_dbg("sock=%p sk=%p len=%zu flags=%d", sock, sk, len, flags);
+
+        skb = skb_recv_datagram(sk, flags, noblock, &rc);
+        if (!skb)
+                return rc;
+
+        msg->msg_namelen = 0;
+
+        copied = skb->len;
+        if (len < copied) {
+                msg->msg_flags |= MSG_TRUNC;
+                copied = len;
+        }
+
+        rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
+
+        skb_free_datagram(sk, skb);
+
+        return rc ? : copied;
+}
+
+
+static const struct proto_ops rawsock_ops = {
+        .family         = PF_NFC,
+        .owner          = THIS_MODULE,
+        .release        = rawsock_release,
+        .bind           = sock_no_bind,
+        .connect        = rawsock_connect,
+        .socketpair     = sock_no_socketpair,
+        .accept         = sock_no_accept,
+        .getname        = sock_no_getname,
+        .poll           = datagram_poll,
+        .ioctl          = sock_no_ioctl,
+        .listen         = sock_no_listen,
+        .shutdown       = sock_no_shutdown,
+        .setsockopt     = sock_no_setsockopt,
+        .getsockopt     = sock_no_getsockopt,
+        .sendmsg        = rawsock_sendmsg,
+        .recvmsg        = rawsock_recvmsg,
+        .mmap           = sock_no_mmap,
+};
+
+static void rawsock_destruct(struct sock *sk)
+{
+        nfc_dbg("sk=%p", sk);
+
+        if (sk->sk_state == TCP_ESTABLISHED) {
+                nfc_deactivate_target(nfc_rawsock(sk)->dev,
+                                        nfc_rawsock(sk)->target_idx);
+                nfc_put_device(nfc_rawsock(sk)->dev);
+        }
+
+        skb_queue_purge(&sk->sk_receive_queue);
+
+        if (!sock_flag(sk, SOCK_DEAD)) {
+                nfc_err("Freeing alive NFC raw socket %p", sk);
+                return;
+        }
+}
+
+static int rawsock_create(struct net *net, struct socket *sock,
+                                const struct nfc_protocol *nfc_proto)
+{
+        struct sock *sk;
+
+        nfc_dbg("sock=%p", sock);
+
+        if (sock->type != SOCK_SEQPACKET)
+                return -ESOCKTNOSUPPORT;
+
+        sock->ops = &rawsock_ops;
+
+        sk = sk_alloc(net, PF_NFC, GFP_KERNEL, nfc_proto->proto);
+        if (!sk)
+                return -ENOMEM;
+
+        sock_init_data(sock, sk);
+        sk->sk_protocol = nfc_proto->id;
+        sk->sk_destruct = rawsock_destruct;
+        sock->state = SS_UNCONNECTED;
+
+        INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);
+        nfc_rawsock(sk)->tx_work_scheduled = false;
+
+        return 0;
+}
+
+static struct proto rawsock_proto = {
+        .name     = "NFC_RAW",
+        .owner    = THIS_MODULE,
+        .obj_size = sizeof(struct nfc_rawsock),
+};
+
+static const struct nfc_protocol rawsock_nfc_proto = {
+        .id       = NFC_SOCKPROTO_RAW,
+        .proto    = &rawsock_proto,
+        .owner    = THIS_MODULE,
+        .create   = rawsock_create
+};
+
+int __init rawsock_init(void)
+{
+        int rc;
+
+        rc = nfc_proto_register(&rawsock_nfc_proto);
+
+        return rc;
+}
+
+void rawsock_exit(void)
+{
+        nfc_proto_unregister(&rawsock_nfc_proto);
+}