/*
 * Copyright (c) 2013, Cisco Systems, Inc. All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/bitmap.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <net/inet_sock.h>

#include "usnic_transport.h"
#include "usnic_log.h"

/* ROCE */
static unsigned long *roce_bitmap;
static u16 roce_next_port = 1;
#define ROCE_BITMAP_SZ ((1 << (8 /*CHAR_BIT*/ * sizeof(u16)))/8 /*CHAR BIT*/)
static DEFINE_SPINLOCK(roce_bitmap_lock);

const char *usnic_transport_to_str(enum usnic_transport_type type)
{
        switch (type) {
        case USNIC_TRANSPORT_UNKNOWN:
                return "Unknown";
        case USNIC_TRANSPORT_ROCE_CUSTOM:
                return "roce custom";
        case USNIC_TRANSPORT_IPV4_UDP:
                return "IPv4 UDP";
        case USNIC_TRANSPORT_MAX:
                return "Max?";
        default:
                return "Not known";
        }
}

int usnic_transport_sock_to_str(char *buf, int buf_sz,
                                        struct socket *sock)
{
        int err;
        uint32_t addr;
        uint16_t port;
        int proto;

        memset(buf, 0, buf_sz);
        err = usnic_transport_sock_get_addr(sock, &proto, &addr, &port);
        if (err)
                return 0;

        return scnprintf(buf, buf_sz, "Proto:%u Addr:%pI4h Port:%hu",
                        proto, &addr, port);
}

/*
 * reserve a port number.  if "0" specified, we will try to pick one
 * starting at roce_next_port.  roce_next_port will take on the values
 * 1..4096
 */
u16 usnic_transport_rsrv_port(enum usnic_transport_type type, u16 port_num)
{
        if (type == USNIC_TRANSPORT_ROCE_CUSTOM) {
                spin_lock(&roce_bitmap_lock);
                if (!port_num) {
                        port_num = bitmap_find_next_zero_area(roce_bitmap,
                                                ROCE_BITMAP_SZ,
                                                roce_next_port /* start */,
                                                1 /* nr */,
                                                0 /* align */);
                        roce_next_port = (port_num & 4095) + 1;
                } else if (test_bit(port_num, roce_bitmap)) {
                        usnic_err("Failed to allocate port for %s\n",
                                        usnic_transport_to_str(type));
                        spin_unlock(&roce_bitmap_lock);
                        goto out_fail;
                }
                bitmap_set(roce_bitmap, port_num, 1);
                spin_unlock(&roce_bitmap_lock);
        } else {
                usnic_err("Failed to allocate port - transport %s unsupported\n",
                                usnic_transport_to_str(type));
                goto out_fail;
        }

        usnic_dbg("Allocating port %hu for %s\n", port_num,
                        usnic_transport_to_str(type));
        return port_num;

out_fail:
        return 0;
}

void usnic_transport_unrsrv_port(enum usnic_transport_type type, u16 port_num)
{
        if (type == USNIC_TRANSPORT_ROCE_CUSTOM) {
                spin_lock(&roce_bitmap_lock);
                if (!port_num) {
                        usnic_err("Unreserved unvalid port num 0 for %s\n",
                                        usnic_transport_to_str(type));
                        goto out_roce_custom;
                }

                if (!test_bit(port_num, roce_bitmap)) {
                        usnic_err("Unreserving invalid %hu for %s\n",
                                        port_num,
                                        usnic_transport_to_str(type));
                        goto out_roce_custom;
                }
                bitmap_clear(roce_bitmap, port_num, 1);
                usnic_dbg("Freeing port %hu for %s\n", port_num,
                                usnic_transport_to_str(type));
out_roce_custom:
                spin_unlock(&roce_bitmap_lock);
        } else {
                usnic_err("Freeing invalid port %hu for %d\n", port_num, type);
        }
}

struct socket *usnic_transport_get_socket(int sock_fd)
{
        struct socket *sock;
        int err;
        char buf[25];

        /* sockfd_lookup will internally do a fget */
        sock = sockfd_lookup(sock_fd, &err);
        if (!sock) {
                usnic_err("Unable to lookup socket for fd %d with err %d\n",
                                sock_fd, err);
                return ERR_PTR(-ENOENT);
        }

        usnic_transport_sock_to_str(buf, sizeof(buf), sock);
        usnic_dbg("Get sock %s\n", buf);

        return sock;
}

void usnic_transport_put_socket(struct socket *sock)
{
        char buf[100];

        usnic_transport_sock_to_str(buf, sizeof(buf), sock);
        usnic_dbg("Put sock %s\n", buf);
        sockfd_put(sock);
}

int usnic_transport_sock_get_addr(struct socket *sock, int *proto,
                                        uint32_t *addr, uint16_t *port)
{
        int len;
        int err;
        struct sockaddr_in sock_addr;

        err = sock->ops->getname(sock,
                                (struct sockaddr *)&sock_addr,
                                &len, 0);
        if (err)
                return err;

        if (sock_addr.sin_family != AF_INET)
                return -EINVAL;

        if (proto)
                *proto = sock->sk->sk_protocol;
        if (port)
                *port = ntohs(((struct sockaddr_in *)&sock_addr)->sin_port);
        if (addr)
                *addr = ntohl(((struct sockaddr_in *)
                                        &sock_addr)->sin_addr.s_addr);

        return 0;
}

int usnic_transport_init(void)
{
        roce_bitmap = kzalloc(ROCE_BITMAP_SZ, GFP_KERNEL);
        if (!roce_bitmap) {
                usnic_err("Failed to allocate bit map");
                return -ENOMEM;
        }

        /* Do not ever allocate bit 0, hence set it here */
        bitmap_set(roce_bitmap, 0, 1);
        return 0;
}

void usnic_transport_fini(void)
{
        kfree(roce_bitmap);
}