/*
 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * 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/kernel.h>
#include <net/sock.h>
#include <linux/in.h>
#include <linux/ipv6.h>
#include <linux/if_arp.h>
#include <linux/jhash.h>
#include <linux/ratelimit.h>
#include "rds.h"

static struct rhashtable bind_hash_table;

static const struct rhashtable_params ht_parms = {
        .nelem_hint = 768,
        .key_len = RDS_BOUND_KEY_LEN,
        .key_offset = offsetof(struct rds_sock, rs_bound_key),
        .head_offset = offsetof(struct rds_sock, rs_bound_node),
        .max_size = 16384,
        .min_size = 1024,
};

/* Create a key for the bind hash table manipulation.  Port is in network byte
 * order.
 */
static inline void __rds_create_bind_key(u8 *key, const struct in6_addr *addr,
                                         __be16 port, __u32 scope_id)
{
        memcpy(key, addr, sizeof(*addr));
        key += sizeof(*addr);
        memcpy(key, &port, sizeof(port));
        key += sizeof(port);
        memcpy(key, &scope_id, sizeof(scope_id));
}

/*
 * Return the rds_sock bound at the given local address.
 *
 * The rx path can race with rds_release.  We notice if rds_release() has
 * marked this socket and don't return a rs ref to the rx path.
 */
struct rds_sock *rds_find_bound(const struct in6_addr *addr, __be16 port,
                                __u32 scope_id)
{
        u8 key[RDS_BOUND_KEY_LEN];
        struct rds_sock *rs;

        __rds_create_bind_key(key, addr, port, scope_id);
        rcu_read_lock();
        rs = rhashtable_lookup(&bind_hash_table, key, ht_parms);
        if (rs && (sock_flag(rds_rs_to_sk(rs), SOCK_DEAD) ||
                   !refcount_inc_not_zero(&rds_rs_to_sk(rs)->sk_refcnt)))
                rs = NULL;

        rcu_read_unlock();

        rdsdebug("returning rs %p for %pI6c:%u\n", rs, addr,
                 ntohs(port));

        return rs;
}

/* returns -ve errno or +ve port */
static int rds_add_bound(struct rds_sock *rs, const struct in6_addr *addr,
                         __be16 *port, __u32 scope_id)
{
        int ret = -EADDRINUSE;
        u16 rover, last;
        u8 key[RDS_BOUND_KEY_LEN];

        if (*port != 0) {
                rover = be16_to_cpu(*port);
                if (rover == RDS_FLAG_PROBE_PORT)
                        return -EINVAL;
                last = rover;
        } else {
                rover = max_t(u16, get_random_u16(), 2);
                last = rover - 1;
        }

        do {
                if (rover == 0)
                        rover++;

                if (rover == RDS_FLAG_PROBE_PORT)
                        continue;
                __rds_create_bind_key(key, addr, cpu_to_be16(rover),
                                      scope_id);
                if (rhashtable_lookup_fast(&bind_hash_table, key, ht_parms))
                        continue;

                memcpy(rs->rs_bound_key, key, sizeof(rs->rs_bound_key));
                rs->rs_bound_addr = *addr;
                net_get_random_once(&rs->rs_hash_initval,
                                    sizeof(rs->rs_hash_initval));
                rs->rs_bound_port = cpu_to_be16(rover);
                rs->rs_bound_node.next = NULL;
                rds_sock_addref(rs);
                if (!rhashtable_insert_fast(&bind_hash_table,
                                            &rs->rs_bound_node, ht_parms)) {
                        *port = rs->rs_bound_port;
                        rs->rs_bound_scope_id = scope_id;
                        ret = 0;
                        rdsdebug("rs %p binding to %pI6c:%d\n",
                                 rs, addr, (int)ntohs(*port));
                        break;
                } else {
                        rs->rs_bound_addr = in6addr_any;
                        rds_sock_put(rs);
                        ret = -ENOMEM;
                        break;
                }
        } while (rover++ != last);

        return ret;
}

void rds_remove_bound(struct rds_sock *rs)
{

        if (ipv6_addr_any(&rs->rs_bound_addr))
                return;

        rdsdebug("rs %p unbinding from %pI6c:%d\n",
                 rs, &rs->rs_bound_addr,
                 ntohs(rs->rs_bound_port));

        rhashtable_remove_fast(&bind_hash_table, &rs->rs_bound_node, ht_parms);
        rds_sock_put(rs);
        rs->rs_bound_addr = in6addr_any;
}

int rds_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len)
{
        struct sock *sk = sock->sk;
        struct rds_sock *rs = rds_sk_to_rs(sk);
        struct in6_addr v6addr, *binding_addr;
        struct rds_transport *trans;
        __u32 scope_id = 0;
        int ret = 0;
        __be16 port;

        /* We allow an RDS socket to be bound to either IPv4 or IPv6
         * address.
         */
        if (addr_len < offsetofend(struct sockaddr, sa_family))
                return -EINVAL;
        if (uaddr->sa_family == AF_INET) {
                struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;

                if (addr_len < sizeof(struct sockaddr_in) ||
                    sin->sin_addr.s_addr == htonl(INADDR_ANY) ||
                    sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||
                    ipv4_is_multicast(sin->sin_addr.s_addr))
                        return -EINVAL;
                ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &v6addr);
                binding_addr = &v6addr;
                port = sin->sin_port;
#if IS_ENABLED(CONFIG_IPV6)
        } else if (uaddr->sa_family == AF_INET6) {
                struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)uaddr;
                int addr_type;

                if (addr_len < sizeof(struct sockaddr_in6))
                        return -EINVAL;
                addr_type = ipv6_addr_type(&sin6->sin6_addr);
                if (!(addr_type & IPV6_ADDR_UNICAST)) {
                        __be32 addr4;

                        if (!(addr_type & IPV6_ADDR_MAPPED))
                                return -EINVAL;

                        /* It is a mapped address.  Need to do some sanity
                         * checks.
                         */
                        addr4 = sin6->sin6_addr.s6_addr32[3];
                        if (addr4 == htonl(INADDR_ANY) ||
                            addr4 == htonl(INADDR_BROADCAST) ||
                            ipv4_is_multicast(addr4))
                                return -EINVAL;
                }
                /* The scope ID must be specified for link local address. */
                if (addr_type & IPV6_ADDR_LINKLOCAL) {
                        if (sin6->sin6_scope_id == 0)
                                return -EINVAL;
                        scope_id = sin6->sin6_scope_id;
                }
                binding_addr = &sin6->sin6_addr;
                port = sin6->sin6_port;
#endif
        } else {
                return -EINVAL;
        }
        lock_sock(sk);

        /* RDS socket does not allow re-binding. */
        if (!ipv6_addr_any(&rs->rs_bound_addr)) {
                ret = -EINVAL;
                goto out;
        }
        /* Socket is connected.  The binding address should have the same
         * scope ID as the connected address, except the case when one is
         * non-link local address (scope_id is 0).
         */
        if (!ipv6_addr_any(&rs->rs_conn_addr) && scope_id &&
            rs->rs_bound_scope_id &&
            scope_id != rs->rs_bound_scope_id) {
                ret = -EINVAL;
                goto out;
        }

        /* The transport can be set using SO_RDS_TRANSPORT option before the
         * socket is bound.
         */
        if (rs->rs_transport) {
                trans = rs->rs_transport;
                if (!trans->laddr_check ||
                    trans->laddr_check(sock_net(sock->sk),
                                       binding_addr, scope_id) != 0) {
                        ret = -ENOPROTOOPT;
                        goto out;
                }
        } else {
                trans = rds_trans_get_preferred(sock_net(sock->sk),
                                                binding_addr, scope_id);
                if (!trans) {
                        ret = -EADDRNOTAVAIL;
                        pr_info_ratelimited("RDS: %s could not find a transport for %pI6c, load rds_tcp or rds_rdma?\n",
                                            __func__, binding_addr);
                        goto out;
                }
                rs->rs_transport = trans;
        }

        sock_set_flag(sk, SOCK_RCU_FREE);
        ret = rds_add_bound(rs, binding_addr, &port, scope_id);
        if (ret)
                rs->rs_transport = NULL;

out:
        release_sock(sk);
        return ret;
}

void rds_bind_lock_destroy(void)
{
        rhashtable_destroy(&bind_hash_table);
}

int rds_bind_lock_init(void)
{
        return rhashtable_init(&bind_hash_table, &ht_parms);
}