NFC: add nfc generic netlink interface

The NFC generic netlink interface exports the NFC control operations
to the user space.

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>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 640 insertions, 3 deletions

diff --git a/net/nfc/Makefile b/net/nfc/Makefile
index 28bee5958687..fa6fc16246d6 100644
--- a/net/nfc/Makefile
+++ b/net/nfc/Makefile
@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_NFC) += nfc.o
 
-nfc-objs := core.o
+nfc-objs := core.o netlink.o
diff --git a/net/nfc/core.c b/net/nfc/core.c
index 19f8035a1ba9..c70f607455c5 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -233,12 +233,60 @@ struct sk_buff *nfc_alloc_skb(unsigned int size, gfp_t gfp)
 }
 EXPORT_SYMBOL(nfc_alloc_skb);
 
+/**
+ * nfc_targets_found - inform that targets were found
+ *
+ * @dev: The nfc device that found the targets
+ * @targets: array of nfc targets found
+ * @ntargets: targets array size
+ *
+ * The device driver must call this function when one or many nfc targets
+ * are found. After calling this function, the device driver must stop
+ * polling for targets.
+ */
+int nfc_targets_found(struct nfc_dev *dev, struct nfc_target *targets,
+                                                        int n_targets)
+{
+        int i;
+
+        nfc_dbg("dev_name=%s n_targets=%d", dev_name(&dev->dev), n_targets);
+
+        dev->polling = false;
+
+        for (i = 0; i < n_targets; i++)
+                targets[i].idx = dev->target_idx++;
+
+        spin_lock_bh(&dev->targets_lock);
+
+        dev->targets_generation++;
+
+        kfree(dev->targets);
+        dev->targets = kmemdup(targets, n_targets * sizeof(struct nfc_target),
+                                                                GFP_ATOMIC);
+
+        if (!dev->targets) {
+                dev->n_targets = 0;
+                spin_unlock_bh(&dev->targets_lock);
+                return -ENOMEM;
+        }
+
+        dev->n_targets = n_targets;
+        spin_unlock_bh(&dev->targets_lock);
+
+        nfc_genl_targets_found(dev);
+
+        return 0;
+}
+EXPORT_SYMBOL(nfc_targets_found);
+
 static void nfc_release(struct device *d)
 {
         struct nfc_dev *dev = to_nfc_dev(d);
 
         nfc_dbg("dev_name=%s", dev_name(&dev->dev));
 
+        nfc_genl_data_exit(&dev->genl_data);
+        kfree(dev->targets);
         kfree(dev);
 }
 
@@ -298,6 +346,12 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
         dev->ops = ops;
         dev->supported_protocols = supported_protocols;
 
+        spin_lock_init(&dev->targets_lock);
+        nfc_genl_data_init(&dev->genl_data);
+
+        /* first generation must not be 0 */
+        dev->targets_generation = 1;
+
         return dev;
 }
 EXPORT_SYMBOL(nfc_allocate_device);
@@ -318,7 +372,16 @@ int nfc_register_device(struct nfc_dev *dev)
         rc = device_add(&dev->dev);
         mutex_unlock(&nfc_devlist_mutex);
 
-        return rc;
+        if (rc < 0)
+                return rc;
+
+        rc = nfc_genl_device_added(dev);
+        if (rc)
+                nfc_dbg("The userspace won't be notified that the device %s was"
+                                                " added", dev_name(&dev->dev));
+
+
+        return 0;
 }
 EXPORT_SYMBOL(nfc_register_device);
 
@@ -329,6 +392,8 @@ EXPORT_SYMBOL(nfc_register_device);
  */
 void nfc_unregister_device(struct nfc_dev *dev)
 {
+        int rc;
+
         nfc_dbg("dev_name=%s", dev_name(&dev->dev));
 
         mutex_lock(&nfc_devlist_mutex);
@@ -341,18 +406,42 @@ void nfc_unregister_device(struct nfc_dev *dev)
         device_unlock(&dev->dev);
 
         mutex_unlock(&nfc_devlist_mutex);
+
+        rc = nfc_genl_device_removed(dev);
+        if (rc)
+                nfc_dbg("The userspace won't be notified that the device %s"
+                                        " was removed", dev_name(&dev->dev));
+
 }
 EXPORT_SYMBOL(nfc_unregister_device);
 
 static int __init nfc_init(void)
 {
+        int rc;
+
         nfc_info("NFC Core ver %s", VERSION);
 
-        return class_register(&nfc_class);
+        rc = class_register(&nfc_class);
+        if (rc)
+                return rc;
+
+        rc = nfc_genl_init();
+        if (rc)
+                goto err_genl;
+
+        /* the first generation must not be 0 */
+        nfc_devlist_generation = 1;
+
+        return 0;
+
+err_genl:
+        class_unregister(&nfc_class);
+        return rc;
 }
 
 static void __exit nfc_exit(void)
 {
+        nfc_genl_exit();
         class_unregister(&nfc_class);
 }
 
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
new file mode 100644
index 000000000000..ccdff7953f7d
--- /dev/null
+++ b/net/nfc/netlink.c
@@ -0,0 +1,537 @@
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *    Aloisio Almeida Jr <aloisio.almeida@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/genetlink.h>
+#include <linux/nfc.h>
+#include <linux/slab.h>
+
+#include "nfc.h"
+
+static struct genl_multicast_group nfc_genl_event_mcgrp = {
+        .name = NFC_GENL_MCAST_EVENT_NAME,
+};
+
+struct genl_family nfc_genl_family = {
+        .id = GENL_ID_GENERATE,
+        .hdrsize = 0,
+        .name = NFC_GENL_NAME,
+        .version = NFC_GENL_VERSION,
+        .maxattr = NFC_ATTR_MAX,
+};
+
+static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
+        [NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
+        [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
+                                .len = NFC_DEVICE_NAME_MAXSIZE },
+        [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
+};
+
+static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
+                                        struct netlink_callback *cb, int flags)
+{
+        void *hdr;
+
+        nfc_dbg("entry");
+
+        hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+                                &nfc_genl_family, flags, NFC_CMD_GET_TARGET);
+        if (!hdr)
+                return -EMSGSIZE;
+
+        genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
+
+        NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target->idx);
+        NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS,
+                                target->supported_protocols);
+        NLA_PUT_U16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res);
+        NLA_PUT_U8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res);
+
+        return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        return -EMSGSIZE;
+}
+
+static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
+{
+        struct nfc_dev *dev;
+        int rc;
+        u32 idx;
+
+        rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
+                                                nfc_genl_family.attrbuf,
+                                                nfc_genl_family.maxattr,
+                                                nfc_genl_policy);
+        if (rc < 0)
+                return ERR_PTR(rc);
+
+        if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
+                return ERR_PTR(-EINVAL);
+
+        idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
+
+        dev = nfc_get_device(idx);
+        if (!dev)
+                return ERR_PTR(-ENODEV);
+
+        return dev;
+}
+
+static int nfc_genl_dump_targets(struct sk_buff *skb,
+                                struct netlink_callback *cb)
+{
+        int i = cb->args[0];
+        struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+        int rc;
+
+        nfc_dbg("entry");
+
+        if (!dev) {
+                dev = __get_device_from_cb(cb);
+                if (IS_ERR(dev))
+                        return PTR_ERR(dev);
+
+                cb->args[1] = (long) dev;
+        }
+
+        spin_lock_bh(&dev->targets_lock);
+
+        cb->seq = dev->targets_generation;
+
+        while (i < dev->n_targets) {
+                rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
+                                                                NLM_F_MULTI);
+                if (rc < 0)
+                        break;
+
+                i++;
+        }
+
+        spin_unlock_bh(&dev->targets_lock);
+
+        cb->args[0] = i;
+
+        return skb->len;
+}
+
+static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
+{
+        struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+
+        nfc_dbg("entry");
+
+        if (dev)
+                nfc_put_device(dev);
+
+        return 0;
+}
+
+int nfc_genl_targets_found(struct nfc_dev *dev)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        nfc_dbg("entry");
+
+        dev->genl_data.poll_req_pid = 0;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                                NFC_EVENT_TARGETS_FOUND);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+
+        genlmsg_end(msg, hdr);
+
+        return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+free_msg:
+        nlmsg_free(msg);
+        return -EMSGSIZE;
+}
+
+int nfc_genl_device_added(struct nfc_dev *dev)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        nfc_dbg("entry");
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                                NFC_EVENT_DEVICE_ADDED);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+        NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
+
+        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_device_removed(struct nfc_dev *dev)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        nfc_dbg("entry");
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                                NFC_EVENT_DEVICE_REMOVED);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+
+        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 pid, u32 seq,
+                                                struct netlink_callback *cb,
+                                                int flags)
+{
+        void *hdr;
+
+        nfc_dbg("entry");
+
+        hdr = genlmsg_put(msg, pid, seq, &nfc_genl_family, flags,
+                                                        NFC_CMD_GET_DEVICE);
+        if (!hdr)
+                return -EMSGSIZE;
+
+        if (cb)
+                genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
+
+        NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+        NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
+
+        return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        return -EMSGSIZE;
+}
+
+static int nfc_genl_dump_devices(struct sk_buff *skb,
+                                struct netlink_callback *cb)
+{
+        struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
+        struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+        bool first_call = false;
+
+        nfc_dbg("entry");
+
+        if (!iter) {
+                first_call = true;
+                iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
+                if (!iter)
+                        return -ENOMEM;
+                cb->args[0] = (long) iter;
+        }
+
+        mutex_lock(&nfc_devlist_mutex);
+
+        cb->seq = nfc_devlist_generation;
+
+        if (first_call) {
+                nfc_device_iter_init(iter);
+                dev = nfc_device_iter_next(iter);
+        }
+
+        while (dev) {
+                int rc;
+
+                rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).pid,
+                                                        cb->nlh->nlmsg_seq,
+                                                        cb, NLM_F_MULTI);
+                if (rc < 0)
+                        break;
+
+                dev = nfc_device_iter_next(iter);
+        }
+
+        mutex_unlock(&nfc_devlist_mutex);
+
+        cb->args[1] = (long) dev;
+
+        return skb->len;
+}
+
+static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
+{
+        struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
+
+        nfc_dbg("entry");
+
+        nfc_device_iter_exit(iter);
+        kfree(iter);
+
+        return 0;
+}
+
+static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
+{
+        struct sk_buff *msg;
+        struct nfc_dev *dev;
+        u32 idx;
+        int rc = -ENOBUFS;
+
+        nfc_dbg("entry");
+
+        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;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg) {
+                rc = -ENOMEM;
+                goto out_putdev;
+        }
+
+        rc = nfc_genl_send_device(msg, dev, info->snd_pid, info->snd_seq,
+                                                                NULL, 0);
+        if (rc < 0)
+                goto out_free;
+
+        nfc_put_device(dev);
+
+        return genlmsg_reply(msg, info);
+
+out_free:
+        nlmsg_free(msg);
+out_putdev:
+        nfc_put_device(dev);
+        return rc;
+}
+
+static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
+{
+        struct nfc_dev *dev;
+        int rc;
+        u32 idx;
+        u32 protocols;
+
+        nfc_dbg("entry");
+
+        if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+                !info->attrs[NFC_ATTR_PROTOCOLS])
+                return -EINVAL;
+
+        idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+        protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
+
+        dev = nfc_get_device(idx);
+        if (!dev)
+                return -ENODEV;
+
+        mutex_lock(&dev->genl_data.genl_data_mutex);
+
+        rc = nfc_start_poll(dev, protocols);
+        if (!rc)
+                dev->genl_data.poll_req_pid = info->snd_pid;
+
+        mutex_unlock(&dev->genl_data.genl_data_mutex);
+
+        nfc_put_device(dev);
+        return rc;
+}
+
+static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
+{
+        struct nfc_dev *dev;
+        int rc;
+        u32 idx;
+
+        nfc_dbg("entry");
+
+        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;
+
+        mutex_lock(&dev->genl_data.genl_data_mutex);
+
+        if (dev->genl_data.poll_req_pid != info->snd_pid) {
+                rc = -EBUSY;
+                goto out;
+        }
+
+        rc = nfc_stop_poll(dev);
+        dev->genl_data.poll_req_pid = 0;
+
+out:
+        mutex_unlock(&dev->genl_data.genl_data_mutex);
+        nfc_put_device(dev);
+        return rc;
+}
+
+static struct genl_ops nfc_genl_ops[] = {
+        {
+                .cmd = NFC_CMD_GET_DEVICE,
+                .doit = nfc_genl_get_device,
+                .dumpit = nfc_genl_dump_devices,
+                .done = nfc_genl_dump_devices_done,
+                .policy = nfc_genl_policy,
+        },
+        {
+                .cmd = NFC_CMD_START_POLL,
+                .doit = nfc_genl_start_poll,
+                .policy = nfc_genl_policy,
+        },
+        {
+                .cmd = NFC_CMD_STOP_POLL,
+                .doit = nfc_genl_stop_poll,
+                .policy = nfc_genl_policy,
+        },
+        {
+                .cmd = NFC_CMD_GET_TARGET,
+                .dumpit = nfc_genl_dump_targets,
+                .done = nfc_genl_dump_targets_done,
+                .policy = nfc_genl_policy,
+        },
+};
+
+static int nfc_genl_rcv_nl_event(struct notifier_block *this,
+                                                unsigned long event, void *ptr)
+{
+        struct netlink_notify *n = ptr;
+        struct class_dev_iter iter;
+        struct nfc_dev *dev;
+
+        if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
+                goto out;
+
+        nfc_dbg("NETLINK_URELEASE event from id %d", n->pid);
+
+        nfc_device_iter_init(&iter);
+        dev = nfc_device_iter_next(&iter);
+
+        while (dev) {
+                mutex_lock(&dev->genl_data.genl_data_mutex);
+                if (dev->genl_data.poll_req_pid == n->pid) {
+                        nfc_stop_poll(dev);
+                        dev->genl_data.poll_req_pid = 0;
+                }
+                mutex_unlock(&dev->genl_data.genl_data_mutex);
+                dev = nfc_device_iter_next(&iter);
+        }
+
+        nfc_device_iter_exit(&iter);
+
+out:
+        return NOTIFY_DONE;
+}
+
+void nfc_genl_data_init(struct nfc_genl_data *genl_data)
+{
+        genl_data->poll_req_pid = 0;
+        mutex_init(&genl_data->genl_data_mutex);
+}
+
+void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
+{
+        mutex_destroy(&genl_data->genl_data_mutex);
+}
+
+static struct notifier_block nl_notifier = {
+        .notifier_call  = nfc_genl_rcv_nl_event,
+};
+
+/**
+ * nfc_genl_init() - Initialize netlink interface
+ *
+ * This initialization function registers the nfc netlink family.
+ */
+int __init nfc_genl_init(void)
+{
+        int rc;
+
+        rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
+                                        ARRAY_SIZE(nfc_genl_ops));
+        if (rc)
+                return rc;
+
+        rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
+
+        netlink_register_notifier(&nl_notifier);
+
+        return rc;
+}
+
+/**
+ * nfc_genl_exit() - Deinitialize netlink interface
+ *
+ * This exit function unregisters the nfc netlink family.
+ */
+void nfc_genl_exit(void)
+{
+        netlink_unregister_notifier(&nl_notifier);
+        genl_unregister_family(&nfc_genl_family);
+}
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
index 55f83f86fe2c..2b31e808e6fb 100644
--- a/net/nfc/nfc.h
+++ b/net/nfc/nfc.h
@@ -36,6 +36,17 @@ int nfc_printk(const char *level, const char *fmt, ...);
 extern int nfc_devlist_generation;
 extern struct mutex nfc_devlist_mutex;
 
+int __init nfc_genl_init(void);
+void nfc_genl_exit(void);
+
+void nfc_genl_data_init(struct nfc_genl_data *genl_data);
+void nfc_genl_data_exit(struct nfc_genl_data *genl_data);
+
+int nfc_genl_targets_found(struct nfc_dev *dev);
+
+int nfc_genl_device_added(struct nfc_dev *dev);
+int nfc_genl_device_removed(struct nfc_dev *dev);
+
 struct nfc_dev *nfc_get_device(unsigned idx);
 
 static inline void nfc_put_device(struct nfc_dev *dev)