/*
 * Copyright (c) 2015, Sony Mobile Communications Inc.
 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 */
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/qrtr.h>
#include <linux/termios.h>      /* For TIOCINQ/OUTQ */

#include <net/sock.h>

#include "qrtr.h"

#define QRTR_PROTO_VER_1 1
#define QRTR_PROTO_VER_2 3

/* auto-bind range */
#define QRTR_MIN_EPH_SOCKET 0x4000
#define QRTR_MAX_EPH_SOCKET 0x7fff

/**
 * struct qrtr_hdr_v1 - (I|R)PCrouter packet header version 1
 * @version: protocol version
 * @type: packet type; one of QRTR_TYPE_*
 * @src_node_id: source node
 * @src_port_id: source port
 * @confirm_rx: boolean; whether a resume-tx packet should be send in reply
 * @size: length of packet, excluding this header
 * @dst_node_id: destination node
 * @dst_port_id: destination port
 */
struct qrtr_hdr_v1 {
        __le32 version;
        __le32 type;
        __le32 src_node_id;
        __le32 src_port_id;
        __le32 confirm_rx;
        __le32 size;
        __le32 dst_node_id;
        __le32 dst_port_id;
} __packed;

/**
 * struct qrtr_hdr_v2 - (I|R)PCrouter packet header later versions
 * @version: protocol version
 * @type: packet type; one of QRTR_TYPE_*
 * @flags: bitmask of QRTR_FLAGS_*
 * @optlen: length of optional header data
 * @size: length of packet, excluding this header and optlen
 * @src_node_id: source node
 * @src_port_id: source port
 * @dst_node_id: destination node
 * @dst_port_id: destination port
 */
struct qrtr_hdr_v2 {
        u8 version;
        u8 type;
        u8 flags;
        u8 optlen;
        __le32 size;
        __le16 src_node_id;
        __le16 src_port_id;
        __le16 dst_node_id;
        __le16 dst_port_id;
};

#define QRTR_FLAGS_CONFIRM_RX   BIT(0)

struct qrtr_cb {
        u32 src_node;
        u32 src_port;
        u32 dst_node;
        u32 dst_port;

        u8 type;
        u8 confirm_rx;
};

#define QRTR_HDR_MAX_SIZE max_t(size_t, sizeof(struct qrtr_hdr_v1), \
                                        sizeof(struct qrtr_hdr_v2))

struct qrtr_sock {
        /* WARNING: sk must be the first member */
        struct sock sk;
        struct sockaddr_qrtr us;
        struct sockaddr_qrtr peer;
};

static inline struct qrtr_sock *qrtr_sk(struct sock *sk)
{
        BUILD_BUG_ON(offsetof(struct qrtr_sock, sk) != 0);
        return container_of(sk, struct qrtr_sock, sk);
}

static unsigned int qrtr_local_nid = -1;

/* for node ids */
static RADIX_TREE(qrtr_nodes, GFP_KERNEL);
/* broadcast list */
static LIST_HEAD(qrtr_all_nodes);
/* lock for qrtr_nodes, qrtr_all_nodes and node reference */
static DEFINE_MUTEX(qrtr_node_lock);

/* local port allocation management */
static DEFINE_IDR(qrtr_ports);
static DEFINE_MUTEX(qrtr_port_lock);

/**
 * struct qrtr_node - endpoint node
 * @ep_lock: lock for endpoint management and callbacks
 * @ep: endpoint
 * @ref: reference count for node
 * @nid: node id
 * @rx_queue: receive queue
 * @work: scheduled work struct for recv work
 * @item: list item for broadcast list
 */
struct qrtr_node {
        struct mutex ep_lock;
        struct qrtr_endpoint *ep;
        struct kref ref;
        unsigned int nid;

        struct sk_buff_head rx_queue;
        struct work_struct work;
        struct list_head item;
};

static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
                              int type, struct sockaddr_qrtr *from,
                              struct sockaddr_qrtr *to);
static int qrtr_bcast_enqueue(struct qrtr_node *node, struct sk_buff *skb,
                              int type, struct sockaddr_qrtr *from,
                              struct sockaddr_qrtr *to);

/* Release node resources and free the node.
 *
 * Do not call directly, use qrtr_node_release.  To be used with
 * kref_put_mutex.  As such, the node mutex is expected to be locked on call.
 */
static void __qrtr_node_release(struct kref *kref)
{
        struct qrtr_node *node = container_of(kref, struct qrtr_node, ref);

        if (node->nid != QRTR_EP_NID_AUTO)
                radix_tree_delete(&qrtr_nodes, node->nid);

        list_del(&node->item);
        mutex_unlock(&qrtr_node_lock);

        skb_queue_purge(&node->rx_queue);
        kfree(node);
}

/* Increment reference to node. */
static struct qrtr_node *qrtr_node_acquire(struct qrtr_node *node)
{
        if (node)
                kref_get(&node->ref);
        return node;
}

/* Decrement reference to node and release as necessary. */
static void qrtr_node_release(struct qrtr_node *node)
{
        if (!node)
                return;
        kref_put_mutex(&node->ref, __qrtr_node_release, &qrtr_node_lock);
}

/* Pass an outgoing packet socket buffer to the endpoint driver. */
static int qrtr_node_enqueue(struct qrtr_node *node, struct sk_buff *skb,
                             int type, struct sockaddr_qrtr *from,
                             struct sockaddr_qrtr *to)
{
        struct qrtr_hdr_v1 *hdr;
        size_t len = skb->len;
        int rc = -ENODEV;

        hdr = skb_push(skb, sizeof(*hdr));
        hdr->version = cpu_to_le32(QRTR_PROTO_VER_1);
        hdr->type = cpu_to_le32(type);
        hdr->src_node_id = cpu_to_le32(from->sq_node);
        hdr->src_port_id = cpu_to_le32(from->sq_port);
        hdr->dst_node_id = cpu_to_le32(to->sq_node);
        hdr->dst_port_id = cpu_to_le32(to->sq_port);

        hdr->size = cpu_to_le32(len);
        hdr->confirm_rx = 0;

        skb_put_padto(skb, ALIGN(len, 4));

        mutex_lock(&node->ep_lock);
        if (node->ep)
                rc = node->ep->xmit(node->ep, skb);
        else
                kfree_skb(skb);
        mutex_unlock(&node->ep_lock);

        return rc;
}

/* Lookup node by id.
 *
 * callers must release with qrtr_node_release()
 */
static struct qrtr_node *qrtr_node_lookup(unsigned int nid)
{
        struct qrtr_node *node;

        mutex_lock(&qrtr_node_lock);
        node = radix_tree_lookup(&qrtr_nodes, nid);
        node = qrtr_node_acquire(node);
        mutex_unlock(&qrtr_node_lock);

        return node;
}

/* Assign node id to node.
 *
 * This is mostly useful for automatic node id assignment, based on
 * the source id in the incoming packet.
 */
static void qrtr_node_assign(struct qrtr_node *node, unsigned int nid)
{
        if (node->nid != QRTR_EP_NID_AUTO || nid == QRTR_EP_NID_AUTO)
                return;

        mutex_lock(&qrtr_node_lock);
        radix_tree_insert(&qrtr_nodes, nid, node);
        node->nid = nid;
        mutex_unlock(&qrtr_node_lock);
}

/**
 * qrtr_endpoint_post() - post incoming data
 * @ep: endpoint handle
 * @data: data pointer
 * @len: size of data in bytes
 *
 * Return: 0 on success; negative error code on failure
 */
int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
{
        struct qrtr_node *node = ep->node;
        const struct qrtr_hdr_v1 *v1;
        const struct qrtr_hdr_v2 *v2;
        struct sk_buff *skb;
        struct qrtr_cb *cb;
        unsigned int size;
        unsigned int ver;
        size_t hdrlen;

        if (len & 3)
                return -EINVAL;

        skb = netdev_alloc_skb(NULL, len);
        if (!skb)
                return -ENOMEM;

        cb = (struct qrtr_cb *)skb->cb;

        /* Version field in v1 is little endian, so this works for both cases */
        ver = *(u8*)data;

        switch (ver) {
        case QRTR_PROTO_VER_1:
                v1 = data;
                hdrlen = sizeof(*v1);

                cb->type = le32_to_cpu(v1->type);
                cb->src_node = le32_to_cpu(v1->src_node_id);
                cb->src_port = le32_to_cpu(v1->src_port_id);
                cb->confirm_rx = !!v1->confirm_rx;
                cb->dst_node = le32_to_cpu(v1->dst_node_id);
                cb->dst_port = le32_to_cpu(v1->dst_port_id);

                size = le32_to_cpu(v1->size);
                break;
        case QRTR_PROTO_VER_2:
                v2 = data;
                hdrlen = sizeof(*v2) + v2->optlen;

                cb->type = v2->type;
                cb->confirm_rx = !!(v2->flags & QRTR_FLAGS_CONFIRM_RX);
                cb->src_node = le16_to_cpu(v2->src_node_id);
                cb->src_port = le16_to_cpu(v2->src_port_id);
                cb->dst_node = le16_to_cpu(v2->dst_node_id);
                cb->dst_port = le16_to_cpu(v2->dst_port_id);

                if (cb->src_port == (u16)QRTR_PORT_CTRL)
                        cb->src_port = QRTR_PORT_CTRL;
                if (cb->dst_port == (u16)QRTR_PORT_CTRL)
                        cb->dst_port = QRTR_PORT_CTRL;

                size = le32_to_cpu(v2->size);
                break;
        default:
                pr_err("qrtr: Invalid version %d\n", ver);
                goto err;
        }

        if (len != ALIGN(size, 4) + hdrlen)
                goto err;

        if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA)
                goto err;

        skb_put_data(skb, data + hdrlen, size);

        skb_queue_tail(&node->rx_queue, skb);
        schedule_work(&node->work);

        return 0;

err:
        kfree_skb(skb);
        return -EINVAL;

}
EXPORT_SYMBOL_GPL(qrtr_endpoint_post);

/**
 * qrtr_alloc_ctrl_packet() - allocate control packet skb
 * @pkt: reference to qrtr_ctrl_pkt pointer
 *
 * Returns newly allocated sk_buff, or NULL on failure
 *
 * This function allocates a sk_buff large enough to carry a qrtr_ctrl_pkt and
 * on success returns a reference to the control packet in @pkt.
 */
static struct sk_buff *qrtr_alloc_ctrl_packet(struct qrtr_ctrl_pkt **pkt)
{
        const int pkt_len = sizeof(struct qrtr_ctrl_pkt);
        struct sk_buff *skb;

        skb = alloc_skb(QRTR_HDR_MAX_SIZE + pkt_len, GFP_KERNEL);
        if (!skb)
                return NULL;

        skb_reserve(skb, QRTR_HDR_MAX_SIZE);
        *pkt = skb_put_zero(skb, pkt_len);

        return skb;
}

static struct qrtr_sock *qrtr_port_lookup(int port);
static void qrtr_port_put(struct qrtr_sock *ipc);

/* Handle and route a received packet.
 *
 * This will auto-reply with resume-tx packet as necessary.
 */
static void qrtr_node_rx_work(struct work_struct *work)
{
        struct qrtr_node *node = container_of(work, struct qrtr_node, work);
        struct qrtr_ctrl_pkt *pkt;
        struct sockaddr_qrtr dst;
        struct sockaddr_qrtr src;
        struct sk_buff *skb;

        while ((skb = skb_dequeue(&node->rx_queue)) != NULL) {
                struct qrtr_sock *ipc;
                struct qrtr_cb *cb;
                int confirm;

                cb = (struct qrtr_cb *)skb->cb;
                src.sq_node = cb->src_node;
                src.sq_port = cb->src_port;
                dst.sq_node = cb->dst_node;
                dst.sq_port = cb->dst_port;
                confirm = !!cb->confirm_rx;

                qrtr_node_assign(node, cb->src_node);

                ipc = qrtr_port_lookup(cb->dst_port);
                if (!ipc) {
                        kfree_skb(skb);
                } else {
                        if (sock_queue_rcv_skb(&ipc->sk, skb))
                                kfree_skb(skb);

                        qrtr_port_put(ipc);
                }

                if (confirm) {
                        skb = qrtr_alloc_ctrl_packet(&pkt);
                        if (!skb)
                                break;

                        pkt->cmd = cpu_to_le32(QRTR_TYPE_RESUME_TX);
                        pkt->client.node = cpu_to_le32(dst.sq_node);
                        pkt->client.port = cpu_to_le32(dst.sq_port);

                        if (qrtr_node_enqueue(node, skb, QRTR_TYPE_RESUME_TX,
                                              &dst, &src))
                                break;
                }
        }
}

/**
 * qrtr_endpoint_register() - register a new endpoint
 * @ep: endpoint to register
 * @nid: desired node id; may be QRTR_EP_NID_AUTO for auto-assignment
 * Return: 0 on success; negative error code on failure
 *
 * The specified endpoint must have the xmit function pointer set on call.
 */
int qrtr_endpoint_register(struct qrtr_endpoint *ep, unsigned int nid)
{
        struct qrtr_node *node;

        if (!ep || !ep->xmit)
                return -EINVAL;

        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (!node)
                return -ENOMEM;

        INIT_WORK(&node->work, qrtr_node_rx_work);
        kref_init(&node->ref);
        mutex_init(&node->ep_lock);
        skb_queue_head_init(&node->rx_queue);
        node->nid = QRTR_EP_NID_AUTO;
        node->ep = ep;

        qrtr_node_assign(node, nid);

        mutex_lock(&qrtr_node_lock);
        list_add(&node->item, &qrtr_all_nodes);
        mutex_unlock(&qrtr_node_lock);
        ep->node = node;

        return 0;
}
EXPORT_SYMBOL_GPL(qrtr_endpoint_register);

/**
 * qrtr_endpoint_unregister - unregister endpoint
 * @ep: endpoint to unregister
 */
void qrtr_endpoint_unregister(struct qrtr_endpoint *ep)
{
        struct qrtr_node *node = ep->node;
        struct sockaddr_qrtr src = {AF_QIPCRTR, node->nid, QRTR_PORT_CTRL};
        struct sockaddr_qrtr dst = {AF_QIPCRTR, qrtr_local_nid, QRTR_PORT_CTRL};
        struct qrtr_ctrl_pkt *pkt;
        struct sk_buff *skb;

        mutex_lock(&node->ep_lock);
        node->ep = NULL;
        mutex_unlock(&node->ep_lock);

        /* Notify the local controller about the event */
        skb = qrtr_alloc_ctrl_packet(&pkt);
        if (skb) {
                pkt->cmd = cpu_to_le32(QRTR_TYPE_BYE);
                qrtr_local_enqueue(NULL, skb, QRTR_TYPE_BYE, &src, &dst);
        }

        qrtr_node_release(node);
        ep->node = NULL;
}
EXPORT_SYMBOL_GPL(qrtr_endpoint_unregister);

/* Lookup socket by port.
 *
 * Callers must release with qrtr_port_put()
 */
static struct qrtr_sock *qrtr_port_lookup(int port)
{
        struct qrtr_sock *ipc;

        if (port == QRTR_PORT_CTRL)
                port = 0;

        mutex_lock(&qrtr_port_lock);
        ipc = idr_find(&qrtr_ports, port);
        if (ipc)
                sock_hold(&ipc->sk);
        mutex_unlock(&qrtr_port_lock);

        return ipc;
}

/* Release acquired socket. */
static void qrtr_port_put(struct qrtr_sock *ipc)
{
        sock_put(&ipc->sk);
}

/* Remove port assignment. */
static void qrtr_port_remove(struct qrtr_sock *ipc)
{
        struct qrtr_ctrl_pkt *pkt;
        struct sk_buff *skb;
        int port = ipc->us.sq_port;
        struct sockaddr_qrtr to;

        to.sq_family = AF_QIPCRTR;
        to.sq_node = QRTR_NODE_BCAST;
        to.sq_port = QRTR_PORT_CTRL;

        skb = qrtr_alloc_ctrl_packet(&pkt);
        if (skb) {
                pkt->cmd = cpu_to_le32(QRTR_TYPE_DEL_CLIENT);
                pkt->client.node = cpu_to_le32(ipc->us.sq_node);
                pkt->client.port = cpu_to_le32(ipc->us.sq_port);

                skb_set_owner_w(skb, &ipc->sk);
                qrtr_bcast_enqueue(NULL, skb, QRTR_TYPE_DEL_CLIENT, &ipc->us,
                                   &to);
        }

        if (port == QRTR_PORT_CTRL)
                port = 0;

        __sock_put(&ipc->sk);

        mutex_lock(&qrtr_port_lock);
        idr_remove(&qrtr_ports, port);
        mutex_unlock(&qrtr_port_lock);
}

/* Assign port number to socket.
 *
 * Specify port in the integer pointed to by port, and it will be adjusted
 * on return as necesssary.
 *
 * Port may be:
 *   0: Assign ephemeral port in [QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET]
 *   <QRTR_MIN_EPH_SOCKET: Specified; requires CAP_NET_ADMIN
 *   >QRTR_MIN_EPH_SOCKET: Specified; available to all
 */
static int qrtr_port_assign(struct qrtr_sock *ipc, int *port)
{
        int rc;

        mutex_lock(&qrtr_port_lock);
        if (!*port) {
                rc = idr_alloc(&qrtr_ports, ipc,
                               QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET + 1,
                               GFP_ATOMIC);
                if (rc >= 0)
                        *port = rc;
        } else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) {
                rc = -EACCES;
        } else if (*port == QRTR_PORT_CTRL) {
                rc = idr_alloc(&qrtr_ports, ipc, 0, 1, GFP_ATOMIC);
        } else {
                rc = idr_alloc(&qrtr_ports, ipc, *port, *port + 1, GFP_ATOMIC);
                if (rc >= 0)
                        *port = rc;
        }
        mutex_unlock(&qrtr_port_lock);

        if (rc == -ENOSPC)
                return -EADDRINUSE;
        else if (rc < 0)
                return rc;

        sock_hold(&ipc->sk);

        return 0;
}

/* Reset all non-control ports */
static void qrtr_reset_ports(void)
{
        struct qrtr_sock *ipc;
        int id;

        mutex_lock(&qrtr_port_lock);
        idr_for_each_entry(&qrtr_ports, ipc, id) {
                /* Don't reset control port */
                if (id == 0)
                        continue;

                sock_hold(&ipc->sk);
                ipc->sk.sk_err = ENETRESET;
                ipc->sk.sk_error_report(&ipc->sk);
                sock_put(&ipc->sk);
        }
        mutex_unlock(&qrtr_port_lock);
}

/* Bind socket to address.
 *
 * Socket should be locked upon call.
 */
static int __qrtr_bind(struct socket *sock,
                       const struct sockaddr_qrtr *addr, int zapped)
{
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        int port;
        int rc;

        /* rebinding ok */
        if (!zapped && addr->sq_port == ipc->us.sq_port)
                return 0;

        port = addr->sq_port;
        rc = qrtr_port_assign(ipc, &port);
        if (rc)
                return rc;

        /* unbind previous, if any */
        if (!zapped)
                qrtr_port_remove(ipc);
        ipc->us.sq_port = port;

        sock_reset_flag(sk, SOCK_ZAPPED);

        /* Notify all open ports about the new controller */
        if (port == QRTR_PORT_CTRL)
                qrtr_reset_ports();

        return 0;
}

/* Auto bind to an ephemeral port. */
static int qrtr_autobind(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct sockaddr_qrtr addr;

        if (!sock_flag(sk, SOCK_ZAPPED))
                return 0;

        addr.sq_family = AF_QIPCRTR;
        addr.sq_node = qrtr_local_nid;
        addr.sq_port = 0;

        return __qrtr_bind(sock, &addr, 1);
}

/* Bind socket to specified sockaddr. */
static int qrtr_bind(struct socket *sock, struct sockaddr *saddr, int len)
{
        DECLARE_SOCKADDR(struct sockaddr_qrtr *, addr, saddr);
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        int rc;

        if (len < sizeof(*addr) || addr->sq_family != AF_QIPCRTR)
                return -EINVAL;

        if (addr->sq_node != ipc->us.sq_node)
                return -EINVAL;

        lock_sock(sk);
        rc = __qrtr_bind(sock, addr, sock_flag(sk, SOCK_ZAPPED));
        release_sock(sk);

        return rc;
}

/* Queue packet to local peer socket. */
static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
                              int type, struct sockaddr_qrtr *from,
                              struct sockaddr_qrtr *to)
{
        struct qrtr_sock *ipc;
        struct qrtr_cb *cb;

        ipc = qrtr_port_lookup(to->sq_port);
        if (!ipc || &ipc->sk == skb->sk) { /* do not send to self */
                kfree_skb(skb);
                return -ENODEV;
        }

        cb = (struct qrtr_cb *)skb->cb;
        cb->src_node = from->sq_node;
        cb->src_port = from->sq_port;

        if (sock_queue_rcv_skb(&ipc->sk, skb)) {
                qrtr_port_put(ipc);
                kfree_skb(skb);
                return -ENOSPC;
        }

        qrtr_port_put(ipc);

        return 0;
}

/* Queue packet for broadcast. */
static int qrtr_bcast_enqueue(struct qrtr_node *node, struct sk_buff *skb,
                              int type, struct sockaddr_qrtr *from,
                              struct sockaddr_qrtr *to)
{
        struct sk_buff *skbn;

        mutex_lock(&qrtr_node_lock);
        list_for_each_entry(node, &qrtr_all_nodes, item) {
                skbn = skb_clone(skb, GFP_KERNEL);
                if (!skbn)
                        break;
                skb_set_owner_w(skbn, skb->sk);
                qrtr_node_enqueue(node, skbn, type, from, to);
        }
        mutex_unlock(&qrtr_node_lock);

        qrtr_local_enqueue(node, skb, type, from, to);

        return 0;
}

static int qrtr_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
        DECLARE_SOCKADDR(struct sockaddr_qrtr *, addr, msg->msg_name);
        int (*enqueue_fn)(struct qrtr_node *, struct sk_buff *, int,
                          struct sockaddr_qrtr *, struct sockaddr_qrtr *);
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        struct qrtr_node *node;
        struct sk_buff *skb;
        size_t plen;
        u32 type = QRTR_TYPE_DATA;
        int rc;

        if (msg->msg_flags & ~(MSG_DONTWAIT))
                return -EINVAL;

        if (len > 65535)
                return -EMSGSIZE;

        lock_sock(sk);

        if (addr) {
                if (msg->msg_namelen < sizeof(*addr)) {
                        release_sock(sk);
                        return -EINVAL;
                }

                if (addr->sq_family != AF_QIPCRTR) {
                        release_sock(sk);
                        return -EINVAL;
                }

                rc = qrtr_autobind(sock);
                if (rc) {
                        release_sock(sk);
                        return rc;
                }
        } else if (sk->sk_state == TCP_ESTABLISHED) {
                addr = &ipc->peer;
        } else {
                release_sock(sk);
                return -ENOTCONN;
        }

        node = NULL;
        if (addr->sq_node == QRTR_NODE_BCAST) {
                enqueue_fn = qrtr_bcast_enqueue;
        } else if (addr->sq_node == ipc->us.sq_node) {
                enqueue_fn = qrtr_local_enqueue;
        } else {
                enqueue_fn = qrtr_node_enqueue;
                node = qrtr_node_lookup(addr->sq_node);
                if (!node) {
                        release_sock(sk);
                        return -ECONNRESET;
                }
        }

        plen = (len + 3) & ~3;
        skb = sock_alloc_send_skb(sk, plen + QRTR_HDR_MAX_SIZE,
                                  msg->msg_flags & MSG_DONTWAIT, &rc);
        if (!skb)
                goto out_node;

        skb_reserve(skb, QRTR_HDR_MAX_SIZE);

        rc = memcpy_from_msg(skb_put(skb, len), msg, len);
        if (rc) {
                kfree_skb(skb);
                goto out_node;
        }

        if (ipc->us.sq_port == QRTR_PORT_CTRL) {
                if (len < 4) {
                        rc = -EINVAL;
                        kfree_skb(skb);
                        goto out_node;
                }

                /* control messages already require the type as 'command' */
                skb_copy_bits(skb, 0, &type, 4);
                type = le32_to_cpu(type);
        }

        rc = enqueue_fn(node, skb, type, &ipc->us, addr);
        if (rc >= 0)
                rc = len;

out_node:
        qrtr_node_release(node);
        release_sock(sk);

        return rc;
}

static int qrtr_recvmsg(struct socket *sock, struct msghdr *msg,
                        size_t size, int flags)
{
        DECLARE_SOCKADDR(struct sockaddr_qrtr *, addr, msg->msg_name);
        struct sock *sk = sock->sk;
        struct sk_buff *skb;
        struct qrtr_cb *cb;
        int copied, rc;

        lock_sock(sk);

        if (sock_flag(sk, SOCK_ZAPPED)) {
                release_sock(sk);
                return -EADDRNOTAVAIL;
        }

        skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
                                flags & MSG_DONTWAIT, &rc);
        if (!skb) {
                release_sock(sk);
                return rc;
        }

        copied = skb->len;
        if (copied > size) {
                copied = size;
                msg->msg_flags |= MSG_TRUNC;
        }

        rc = skb_copy_datagram_msg(skb, 0, msg, copied);
        if (rc < 0)
                goto out;
        rc = copied;

        if (addr) {
                cb = (struct qrtr_cb *)skb->cb;
                addr->sq_family = AF_QIPCRTR;
                addr->sq_node = cb->src_node;
                addr->sq_port = cb->src_port;
                msg->msg_namelen = sizeof(*addr);
        }

out:
        skb_free_datagram(sk, skb);
        release_sock(sk);

        return rc;
}

static int qrtr_connect(struct socket *sock, struct sockaddr *saddr,
                        int len, int flags)
{
        DECLARE_SOCKADDR(struct sockaddr_qrtr *, addr, saddr);
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        int rc;

        if (len < sizeof(*addr) || addr->sq_family != AF_QIPCRTR)
                return -EINVAL;

        lock_sock(sk);

        sk->sk_state = TCP_CLOSE;
        sock->state = SS_UNCONNECTED;

        rc = qrtr_autobind(sock);
        if (rc) {
                release_sock(sk);
                return rc;
        }

        ipc->peer = *addr;
        sock->state = SS_CONNECTED;
        sk->sk_state = TCP_ESTABLISHED;

        release_sock(sk);

        return 0;
}

static int qrtr_getname(struct socket *sock, struct sockaddr *saddr,
                        int *len, int peer)
{
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sockaddr_qrtr qaddr;
        struct sock *sk = sock->sk;

        lock_sock(sk);
        if (peer) {
                if (sk->sk_state != TCP_ESTABLISHED) {
                        release_sock(sk);
                        return -ENOTCONN;
                }

                qaddr = ipc->peer;
        } else {
                qaddr = ipc->us;
        }
        release_sock(sk);

        *len = sizeof(qaddr);
        qaddr.sq_family = AF_QIPCRTR;

        memcpy(saddr, &qaddr, sizeof(qaddr));

        return 0;
}

static int qrtr_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        void __user *argp = (void __user *)arg;
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        struct sockaddr_qrtr *sq;
        struct sk_buff *skb;
        struct ifreq ifr;
        long len = 0;
        int rc = 0;

        lock_sock(sk);

        switch (cmd) {
        case TIOCOUTQ:
                len = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
                if (len < 0)
                        len = 0;
                rc = put_user(len, (int __user *)argp);
                break;
        case TIOCINQ:
                skb = skb_peek(&sk->sk_receive_queue);
                if (skb)
                        len = skb->len;
                rc = put_user(len, (int __user *)argp);
                break;
        case SIOCGIFADDR:
                if (copy_from_user(&ifr, argp, sizeof(ifr))) {
                        rc = -EFAULT;
                        break;
                }

                sq = (struct sockaddr_qrtr *)&ifr.ifr_addr;
                *sq = ipc->us;
                if (copy_to_user(argp, &ifr, sizeof(ifr))) {
                        rc = -EFAULT;
                        break;
                }
                break;
        case SIOCGSTAMP:
                rc = sock_get_timestamp(sk, argp);
                break;
        case SIOCADDRT:
        case SIOCDELRT:
        case SIOCSIFADDR:
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFBRDADDR:
        case SIOCSIFBRDADDR:
        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
                rc = -EINVAL;
                break;
        default:
                rc = -ENOIOCTLCMD;
                break;
        }

        release_sock(sk);

        return rc;
}

static int qrtr_release(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct qrtr_sock *ipc;

        if (!sk)
                return 0;

        lock_sock(sk);

        ipc = qrtr_sk(sk);
        sk->sk_shutdown = SHUTDOWN_MASK;
        if (!sock_flag(sk, SOCK_DEAD))
                sk->sk_state_change(sk);

        sock_set_flag(sk, SOCK_DEAD);
        sock->sk = NULL;

        if (!sock_flag(sk, SOCK_ZAPPED))
                qrtr_port_remove(ipc);

        skb_queue_purge(&sk->sk_receive_queue);

        release_sock(sk);
        sock_put(sk);

        return 0;
}

static const struct proto_ops qrtr_proto_ops = {
        .owner          = THIS_MODULE,
        .family         = AF_QIPCRTR,
        .bind           = qrtr_bind,
        .connect        = qrtr_connect,
        .socketpair     = sock_no_socketpair,
        .accept         = sock_no_accept,
        .listen         = sock_no_listen,
        .sendmsg        = qrtr_sendmsg,
        .recvmsg        = qrtr_recvmsg,
        .getname        = qrtr_getname,
        .ioctl          = qrtr_ioctl,
        .poll           = datagram_poll,
        .shutdown       = sock_no_shutdown,
        .setsockopt     = sock_no_setsockopt,
        .getsockopt     = sock_no_getsockopt,
        .release        = qrtr_release,
        .mmap           = sock_no_mmap,
        .sendpage       = sock_no_sendpage,
};

static struct proto qrtr_proto = {
        .name           = "QIPCRTR",
        .owner          = THIS_MODULE,
        .obj_size       = sizeof(struct qrtr_sock),
};

static int qrtr_create(struct net *net, struct socket *sock,
                       int protocol, int kern)
{
        struct qrtr_sock *ipc;
        struct sock *sk;

        if (sock->type != SOCK_DGRAM)
                return -EPROTOTYPE;

        sk = sk_alloc(net, AF_QIPCRTR, GFP_KERNEL, &qrtr_proto, kern);
        if (!sk)
                return -ENOMEM;

        sock_set_flag(sk, SOCK_ZAPPED);

        sock_init_data(sock, sk);
        sock->ops = &qrtr_proto_ops;

        ipc = qrtr_sk(sk);
        ipc->us.sq_family = AF_QIPCRTR;
        ipc->us.sq_node = qrtr_local_nid;
        ipc->us.sq_port = 0;

        return 0;
}

static const struct nla_policy qrtr_policy[IFA_MAX + 1] = {
        [IFA_LOCAL] = { .type = NLA_U32 },
};

static int qrtr_addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
                          struct netlink_ext_ack *extack)
{
        struct nlattr *tb[IFA_MAX + 1];
        struct ifaddrmsg *ifm;
        int rc;

        if (!netlink_capable(skb, CAP_NET_ADMIN))
                return -EPERM;

        if (!netlink_capable(skb, CAP_SYS_ADMIN))
                return -EPERM;

        ASSERT_RTNL();

        rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, qrtr_policy, extack);
        if (rc < 0)
                return rc;

        ifm = nlmsg_data(nlh);
        if (!tb[IFA_LOCAL])
                return -EINVAL;

        qrtr_local_nid = nla_get_u32(tb[IFA_LOCAL]);
        return 0;
}

static const struct net_proto_family qrtr_family = {
        .owner  = THIS_MODULE,
        .family = AF_QIPCRTR,
        .create = qrtr_create,
};

static int __init qrtr_proto_init(void)
{
        int rc;

        rc = proto_register(&qrtr_proto, 1);
        if (rc)
                return rc;

        rc = sock_register(&qrtr_family);
        if (rc) {
                proto_unregister(&qrtr_proto);
                return rc;
        }

        rtnl_register(PF_QIPCRTR, RTM_NEWADDR, qrtr_addr_doit, NULL, 0);

        return 0;
}
postcore_initcall(qrtr_proto_init);

static void __exit qrtr_proto_fini(void)
{
        rtnl_unregister(PF_QIPCRTR, RTM_NEWADDR);
        sock_unregister(qrtr_family.family);
        proto_unregister(&qrtr_proto);
}
module_exit(qrtr_proto_fini);

MODULE_DESCRIPTION("Qualcomm IPC-router driver");
MODULE_LICENSE("GPL v2");