/*      $KAME: keysock.c,v 1.25 2001/08/13 20:07:41 itojun Exp $        */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "opt_ipsec.h"

/* This code has derived from sys/net/rtsock.c on FreeBSD2.2.5 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/domain.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stdarg.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#include <net/if.h>
#include <net/vnet.h>

#include <netinet/in.h>

#include <net/pfkeyv2.h>
#include <netipsec/key.h>
#include <netipsec/keysock.h>
#include <netipsec/key_debug.h>
#include <netipsec/ipsec.h>

static struct mtx keysock_mtx;
MTX_SYSINIT(keysock, &keysock_mtx, "key socket pcb list", MTX_DEF);

#define KEYSOCK_LOCK()          mtx_lock(&keysock_mtx)
#define KEYSOCK_UNLOCK()        mtx_unlock(&keysock_mtx)

VNET_DEFINE_STATIC(LIST_HEAD(, keycb), keycb_list) =
    LIST_HEAD_INITIALIZER(keycb_list);
#define V_keycb_list            VNET(keycb_list)

static struct sockaddr key_src = { 2, PF_KEY, };

static int key_sendup0(struct keycb *, struct mbuf *, int);

VNET_PCPUSTAT_DEFINE(struct pfkeystat, pfkeystat);
VNET_PCPUSTAT_SYSINIT(pfkeystat);

#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(pfkeystat);
#endif /* VIMAGE */

static int
key_send(struct socket *so, int flags, struct mbuf *m,
    struct sockaddr *nam, struct mbuf *control, struct thread *td)
{
        struct sadb_msg *msg;
        int len, error = 0;

        if ((flags & PRUS_OOB) || control != NULL) {
                m_freem(m);
                if (control != NULL)
                        m_freem(control);
                return (EOPNOTSUPP);
        }

        PFKEYSTAT_INC(out_total);
        PFKEYSTAT_ADD(out_bytes, m->m_pkthdr.len);

        len = m->m_pkthdr.len;
        if (len < sizeof(struct sadb_msg)) {
                PFKEYSTAT_INC(out_tooshort);
                error = EINVAL;
                goto end;
        }

        if (m->m_len < sizeof(struct sadb_msg)) {
                if ((m = m_pullup(m, sizeof(struct sadb_msg))) == NULL) {
                        PFKEYSTAT_INC(out_nomem);
                        error = ENOBUFS;
                        goto end;
                }
        }

        M_ASSERTPKTHDR(m);

        KEYDBG(KEY_DUMP, kdebug_mbuf(m));

        msg = mtod(m, struct sadb_msg *);
        PFKEYSTAT_INC(out_msgtype[msg->sadb_msg_type]);
        if (len != PFKEY_UNUNIT64(msg->sadb_msg_len)) {
                PFKEYSTAT_INC(out_invlen);
                error = EINVAL;
                goto end;
        }

        error = key_parse(m, so);
        m = NULL;
end:
        if (m != NULL)
                m_freem(m);
        return (error);
}

/*
 * send message to the socket.
 */
static int
key_sendup0(struct keycb *kp, struct mbuf *m, int promisc)
{

        if (promisc) {
                struct sadb_msg *pmsg;

                M_PREPEND(m, sizeof(struct sadb_msg), M_NOWAIT);
                if (m == NULL) {
                        PFKEYSTAT_INC(in_nomem);
                        return (ENOBUFS);
                }
                pmsg = mtod(m, struct sadb_msg *);
                bzero(pmsg, sizeof(*pmsg));
                pmsg->sadb_msg_version = PF_KEY_V2;
                pmsg->sadb_msg_type = SADB_X_PROMISC;
                pmsg->sadb_msg_len = PFKEY_UNIT64(m->m_pkthdr.len);
                /* pid and seq? */

                PFKEYSTAT_INC(in_msgtype[pmsg->sadb_msg_type]);
        }

        if (!sbappendaddr(&kp->kp_socket->so_rcv, &key_src, m, NULL)) {
                PFKEYSTAT_INC(in_nomem);
                m_freem(m);
                soroverflow(kp->kp_socket);
                return (ENOBUFS);
        }

        sorwakeup(kp->kp_socket);
        return (0);
}

/* so can be NULL if target != KEY_SENDUP_ONE */
int
key_sendup_mbuf(struct socket *so, struct mbuf *m, int target)
{
        struct mbuf *n;
        struct keycb *kp;
        int error = 0;

        KASSERT(m != NULL, ("NULL mbuf pointer was passed."));
        KASSERT(so != NULL || target != KEY_SENDUP_ONE,
            ("NULL socket pointer was passed."));
        KASSERT(target == KEY_SENDUP_ONE || target == KEY_SENDUP_ALL ||
            target == KEY_SENDUP_REGISTERED, ("Wrong target %d", target));

        PFKEYSTAT_INC(in_total);
        PFKEYSTAT_ADD(in_bytes, m->m_pkthdr.len);
        if (m->m_len < sizeof(struct sadb_msg)) {
                m = m_pullup(m, sizeof(struct sadb_msg));
                if (m == NULL) {
                        PFKEYSTAT_INC(in_nomem);
                        return (ENOBUFS);
                }
        }
        if (m->m_len >= sizeof(struct sadb_msg)) {
                struct sadb_msg *msg;
                msg = mtod(m, struct sadb_msg *);
                PFKEYSTAT_INC(in_msgtype[msg->sadb_msg_type]);
        }
        KEYSOCK_LOCK();
        LIST_FOREACH(kp, &V_keycb_list, kp_next) {
                /*
                 * If you are in promiscuous mode, and when you get broadcasted
                 * reply, you'll get two PF_KEY messages.
                 * (based on pf_key@inner.net message on 14 Oct 1998)
                 */
                if (kp->kp_promisc) {
                        n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
                        if (n != NULL)
                                key_sendup0(kp, n, 1);
                        else
                                PFKEYSTAT_INC(in_nomem);
                }

                /* the exact target will be processed later */
                if (so != NULL && so->so_pcb == kp)
                        continue;

                if (target == KEY_SENDUP_ONE || (target ==
                    KEY_SENDUP_REGISTERED && kp->kp_registered == 0))
                        continue;

                /* KEY_SENDUP_ALL + KEY_SENDUP_REGISTERED */
                n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
                if (n == NULL) {
                        PFKEYSTAT_INC(in_nomem);
                        /* Try send to another socket */
                        continue;
                }

                if (key_sendup0(kp, n, 0) == 0)
                        PFKEYSTAT_INC(in_msgtarget[target]);
        }

        if (so) { /* KEY_SENDUP_ONE */
                error = key_sendup0(so->so_pcb, m, 0);
                if (error == 0)
                        PFKEYSTAT_INC(in_msgtarget[KEY_SENDUP_ONE]);
        } else {
                error = 0;
                m_freem(m);
        }
        KEYSOCK_UNLOCK();
        return (error);
}

static u_long key_sendspace = 8192;
SYSCTL_ULONG(_net_key, OID_AUTO, sendspace, CTLFLAG_RW, &key_sendspace, 0,
    "Default key socket send space");
static u_long key_recvspace = 8192;
SYSCTL_ULONG(_net_key, OID_AUTO, recvspace, CTLFLAG_RW, &key_recvspace, 0,
    "Default key socket receive space");

static int
key_attach(struct socket *so, int proto, struct thread *td)
{
        struct keycb *kp;
        int error;

        KASSERT(so->so_pcb == NULL, ("key_attach: so_pcb != NULL"));

        if (td != NULL) {
                error = priv_check(td, PRIV_NET_RAW);
                if (error != 0)
                        return (error);
        }

        error = soreserve(so, key_sendspace, key_recvspace);
        if (error != 0)
                return (error);

        kp = malloc(sizeof(*kp), M_PCB, M_WAITOK);
        kp->kp_socket = so;
        kp->kp_promisc = kp->kp_registered = 0;

        so->so_pcb = kp;
        so->so_options |= SO_USELOOPBACK;

        KEYSOCK_LOCK();
        LIST_INSERT_HEAD(&V_keycb_list, kp, kp_next);
        KEYSOCK_UNLOCK();
        soisconnected(so);

        return (0);
}

static void
key_close(struct socket *so)
{

        soisdisconnected(so);
}

static void
key_detach(struct socket *so)
{
        struct keycb *kp = so->so_pcb;

        key_freereg(so);
        KEYSOCK_LOCK();
        LIST_REMOVE(kp, kp_next);
        KEYSOCK_UNLOCK();
        free(kp, M_PCB);
        so->so_pcb = NULL;
}

static int
key_shutdown(struct socket *so, enum shutdown_how how)
{
        /*
         * Note: key socket marks itself as connected through its lifetime.
         */
        switch (how) {
        case SHUT_RD:
                socantrcvmore(so);
                sbrelease(so, SO_RCV);
                break;
        case SHUT_RDWR:
                socantrcvmore(so);
                sbrelease(so, SO_RCV);
                /* FALLTHROUGH */
        case SHUT_WR:
                socantsendmore(so);
        }

        return (0);
}

SYSCTL_NODE(_net, PF_KEY, key, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Key Family");

static struct protosw keysw = {
        .pr_type =              SOCK_RAW,
        .pr_protocol =          PF_KEY_V2,
        .pr_flags =             PR_ATOMIC | PR_ADDR,
        .pr_abort =             key_close,
        .pr_attach =            key_attach,
        .pr_detach =            key_detach,
        .pr_send =              key_send,
        .pr_shutdown =          key_shutdown,
        .pr_close =             key_close,
};

static struct domain keydomain = {
        .dom_family =           PF_KEY,
        .dom_name =             "key",
        .dom_nprotosw =         1,
        .dom_protosw =          { &keysw },
};
DOMAIN_SET(key);