/*
 * 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

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

enum qrtr_pkt_type {
        QRTR_TYPE_DATA          = 1,
        QRTR_TYPE_HELLO         = 2,
        QRTR_TYPE_BYE           = 3,
        QRTR_TYPE_NEW_SERVER    = 4,
        QRTR_TYPE_DEL_SERVER    = 5,
        QRTR_TYPE_DEL_CLIENT    = 6,
        QRTR_TYPE_RESUME_TX     = 7,
        QRTR_TYPE_EXIT          = 8,
        QRTR_TYPE_PING          = 9,
};

/**
 * struct qrtr_hdr - (I|R)PCrouter packet header
 * @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 {
        __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;

#define QRTR_HDR_SIZE sizeof(struct qrtr_hdr)
#define QRTR_NODE_BCAST ((unsigned int)-1)
#define QRTR_PORT_CTRL ((unsigned int)-2)

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);
static int qrtr_bcast_enqueue(struct qrtr_node *node, struct sk_buff *skb);

/* 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 rc = -ENODEV;

        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 *phdr = data;
        struct sk_buff *skb;
        unsigned int psize;
        unsigned int size;
        unsigned int type;
        unsigned int ver;
        unsigned int dst;

        if (len < QRTR_HDR_SIZE || len & 3)
                return -EINVAL;

        ver = le32_to_cpu(phdr->version);
        size = le32_to_cpu(phdr->size);
        type = le32_to_cpu(phdr->type);
        dst = le32_to_cpu(phdr->dst_port_id);

        psize = (size + 3) & ~3;

        if (ver != QRTR_PROTO_VER)
                return -EINVAL;

        if (len != psize + QRTR_HDR_SIZE)
                return -EINVAL;

        if (dst != QRTR_PORT_CTRL && type != QRTR_TYPE_DATA)
                return -EINVAL;

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

        skb_reset_transport_header(skb);
        skb_put_data(skb, data, len);

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

        return 0;
}
EXPORT_SYMBOL_GPL(qrtr_endpoint_post);

static struct sk_buff *qrtr_alloc_ctrl_packet(u32 type, size_t pkt_len,
                                              u32 src_node, u32 dst_node)
{
        struct qrtr_hdr *hdr;
        struct sk_buff *skb;

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

        hdr = skb_put(skb, QRTR_HDR_SIZE);
        hdr->version = cpu_to_le32(QRTR_PROTO_VER);
        hdr->type = cpu_to_le32(type);
        hdr->src_node_id = cpu_to_le32(src_node);
        hdr->src_port_id = cpu_to_le32(QRTR_PORT_CTRL);
        hdr->confirm_rx = cpu_to_le32(0);
        hdr->size = cpu_to_le32(pkt_len);
        hdr->dst_node_id = cpu_to_le32(dst_node);
        hdr->dst_port_id = cpu_to_le32(QRTR_PORT_CTRL);

        return skb;
}

/* Allocate and construct a resume-tx packet. */
static struct sk_buff *qrtr_alloc_resume_tx(u32 src_node,
                                            u32 dst_node, u32 port)
{
        const int pkt_len = 20;
        struct sk_buff *skb;
        __le32 *buf;

        skb = qrtr_alloc_ctrl_packet(QRTR_TYPE_RESUME_TX, pkt_len,
                                     src_node, dst_node);
        if (!skb)
                return NULL;

        buf = skb_put_zero(skb, pkt_len);
        buf[0] = cpu_to_le32(QRTR_TYPE_RESUME_TX);
        buf[1] = cpu_to_le32(src_node);
        buf[2] = cpu_to_le32(port);

        return skb;
}

/* Allocate and construct a BYE message to signal remote termination */
static struct sk_buff *qrtr_alloc_local_bye(u32 src_node)
{
        const int pkt_len = 20;
        struct sk_buff *skb;
        __le32 *buf;

        skb = qrtr_alloc_ctrl_packet(QRTR_TYPE_BYE, pkt_len,
                                     src_node, qrtr_local_nid);
        if (!skb)
                return NULL;

        buf = skb_put_zero(skb, pkt_len);
        buf[0] = cpu_to_le32(QRTR_TYPE_BYE);

        return skb;
}

static struct sk_buff *qrtr_alloc_del_client(struct sockaddr_qrtr *sq)
{
        const int pkt_len = 20;
        struct sk_buff *skb;
        __le32 *buf;

        skb = qrtr_alloc_ctrl_packet(QRTR_TYPE_DEL_CLIENT, pkt_len,
                                     sq->sq_node, QRTR_NODE_BCAST);
        if (!skb)
                return NULL;

        buf = skb_put_zero(skb, pkt_len);
        buf[0] = cpu_to_le32(QRTR_TYPE_DEL_CLIENT);
        buf[1] = cpu_to_le32(sq->sq_node);
        buf[2] = cpu_to_le32(sq->sq_port);

        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 sk_buff *skb;

        while ((skb = skb_dequeue(&node->rx_queue)) != NULL) {
                const struct qrtr_hdr *phdr;
                u32 dst_node, dst_port;
                struct qrtr_sock *ipc;
                u32 src_node;
                int confirm;

                phdr = (const struct qrtr_hdr *)skb_transport_header(skb);
                src_node = le32_to_cpu(phdr->src_node_id);
                dst_node = le32_to_cpu(phdr->dst_node_id);
                dst_port = le32_to_cpu(phdr->dst_port_id);
                confirm = !!phdr->confirm_rx;

                qrtr_node_assign(node, src_node);

                ipc = qrtr_port_lookup(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_resume_tx(dst_node, node->nid, dst_port);
                        if (!skb)
                                break;
                        if (qrtr_node_enqueue(node, skb))
                                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 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_local_bye(node->nid);
        if (skb)
                qrtr_local_enqueue(NULL, skb);

        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 sk_buff *skb;
        int port = ipc->us.sq_port;

        skb = qrtr_alloc_del_client(&ipc->us);
        if (skb) {
                skb_set_owner_w(skb, &ipc->sk);
                qrtr_bcast_enqueue(NULL, skb);
        }

        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;
                wake_up_interruptible(sk_sleep(&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)
{
        const struct qrtr_hdr *phdr;
        struct qrtr_sock *ipc;

        phdr = (const struct qrtr_hdr *)skb_transport_header(skb);

        ipc = qrtr_port_lookup(le32_to_cpu(phdr->dst_port_id));
        if (!ipc || &ipc->sk == skb->sk) { /* do not send to self */
                kfree_skb(skb);
                return -ENODEV;
        }

        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)
{
        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);
        }
        mutex_unlock(&qrtr_node_lock);

        qrtr_local_enqueue(node, skb);

        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 *);
        struct qrtr_sock *ipc = qrtr_sk(sock->sk);
        struct sock *sk = sock->sk;
        struct qrtr_node *node;
        struct qrtr_hdr *hdr;
        struct sk_buff *skb;
        size_t plen;
        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_SIZE,
                                  msg->msg_flags & MSG_DONTWAIT, &rc);
        if (!skb)
                goto out_node;

        skb_reset_transport_header(skb);
        skb_put(skb, len + QRTR_HDR_SIZE);

        hdr = (struct qrtr_hdr *)skb_transport_header(skb);
        hdr->version = cpu_to_le32(QRTR_PROTO_VER);
        hdr->src_node_id = cpu_to_le32(ipc->us.sq_node);
        hdr->src_port_id = cpu_to_le32(ipc->us.sq_port);
        hdr->confirm_rx = cpu_to_le32(0);
        hdr->size = cpu_to_le32(len);
        hdr->dst_node_id = cpu_to_le32(addr->sq_node);
        hdr->dst_port_id = cpu_to_le32(addr->sq_port);

        rc = skb_copy_datagram_from_iter(skb, QRTR_HDR_SIZE,
                                         &msg->msg_iter, len);
        if (rc) {
                kfree_skb(skb);
                goto out_node;
        }

        if (plen != len) {
                rc = skb_pad(skb, plen - len);
                if (rc)
                        goto out_node;
                skb_put(skb, plen - len);
        }

        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, QRTR_HDR_SIZE, &hdr->type, 4);
        } else {
                hdr->type = cpu_to_le32(QRTR_TYPE_DATA);
        }

        rc = enqueue_fn(node, skb);
        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);
        const struct qrtr_hdr *phdr;
        struct sock *sk = sock->sk;
        struct sk_buff *skb;
        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;
        }

        phdr = (const struct qrtr_hdr *)skb_transport_header(skb);
        copied = le32_to_cpu(phdr->size);
        if (copied > size) {
                copied = size;
                msg->msg_flags |= MSG_TRUNC;
        }

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

        if (addr) {
                addr->sq_family = AF_QIPCRTR;
                addr->sq_node = le32_to_cpu(phdr->src_node_id);
                addr->sq_port = le32_to_cpu(phdr->src_port_id);
                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 - QRTR_HDR_SIZE;
                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, NULL);

        return 0;
}
module_init(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");