/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 *
 * Copyright (c) 1999-2001, Vitaly V Belekhov
 * 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 unmodified, 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/sockio.h>
#include <sys/socket.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_media.h>
#include <net/if_private.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/vnet.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_eiface.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if_arp.h>

static const struct ng_cmdlist ng_eiface_cmdlist[] = {
        {
          NGM_EIFACE_COOKIE,
          NGM_EIFACE_GET_IFNAME,
          "getifname",
          NULL,
          &ng_parse_string_type
        },
        {
          NGM_EIFACE_COOKIE,
          NGM_EIFACE_SET,
          "set",
          &ng_parse_enaddr_type,
          NULL
        },
        { 0 }
};

/* Node private data */
struct ng_eiface_private {
        struct ifnet    *ifp;           /* per-interface network data */
        struct ifmedia  media;          /* (fake) media information */
        int             link_status;    /* fake */
        int             unit;           /* Interface unit number */
        node_p          node;           /* Our netgraph node */
        hook_p          ether;          /* Hook for ethernet stream */
};
typedef struct ng_eiface_private *priv_p;

/* Interface methods */
static void     ng_eiface_init(void *xsc);
static void     ng_eiface_start(struct ifnet *ifp);
static int      ng_eiface_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
#ifdef DEBUG
static void     ng_eiface_print_ioctl(struct ifnet *ifp, int cmd, caddr_t data);
#endif

/* Netgraph methods */
static int              ng_eiface_mod_event(module_t, int, void *);
static ng_constructor_t ng_eiface_constructor;
static ng_rcvmsg_t      ng_eiface_rcvmsg;
static ng_shutdown_t    ng_eiface_rmnode;
static ng_newhook_t     ng_eiface_newhook;
static ng_rcvdata_t     ng_eiface_rcvdata;
static ng_disconnect_t  ng_eiface_disconnect;

/* Node type descriptor */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_EIFACE_NODE_TYPE,
        .mod_event =    ng_eiface_mod_event,
        .constructor =  ng_eiface_constructor,
        .rcvmsg =       ng_eiface_rcvmsg,
        .shutdown =     ng_eiface_rmnode,
        .newhook =      ng_eiface_newhook,
        .rcvdata =      ng_eiface_rcvdata,
        .disconnect =   ng_eiface_disconnect,
        .cmdlist =      ng_eiface_cmdlist
};
NETGRAPH_INIT(eiface, &typestruct);

VNET_DEFINE_STATIC(struct unrhdr *, ng_eiface_unit);
#define V_ng_eiface_unit                VNET(ng_eiface_unit)

/************************************************************************
                        INTERFACE STUFF
 ************************************************************************/

/*
 * Process an ioctl for the virtual interface
 */
static int
ng_eiface_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
        const priv_p priv = (priv_p)ifp->if_softc;
        struct ifreq *const ifr = (struct ifreq *)data;
        int error = 0;

#ifdef DEBUG
        ng_eiface_print_ioctl(ifp, command, data);
#endif
        switch (command) {
        /* These two are mostly handled at a higher layer */
        case SIOCSIFADDR:
                error = ether_ioctl(ifp, command, data);
                break;
        case SIOCGIFADDR:
                break;

        /* Set flags */
        case SIOCSIFFLAGS:
                /*
                 * If the interface is marked up and stopped, then start it.
                 * If it is marked down and running, then stop it.
                 */
                if (ifp->if_flags & IFF_UP) {
                        if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                                ifp->if_drv_flags &= ~(IFF_DRV_OACTIVE);
                                ifp->if_drv_flags |= IFF_DRV_RUNNING;
                        }
                } else {
                        if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                                ifp->if_drv_flags &= ~(IFF_DRV_RUNNING |
                                    IFF_DRV_OACTIVE);
                }
                break;

        /* Set the interface MTU */
        case SIOCSIFMTU:
                if (ifr->ifr_mtu > NG_EIFACE_MTU_MAX ||
                    ifr->ifr_mtu < NG_EIFACE_MTU_MIN)
                        error = EINVAL;
                else
                        ifp->if_mtu = ifr->ifr_mtu;
                break;

        /* (Fake) media type manipulation */
        case SIOCSIFMEDIA:
        case SIOCGIFMEDIA:
                error = ifmedia_ioctl(ifp, ifr, &priv->media, command);
                break;

        /* Stuff that's not supported */
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                error = 0;
                break;
        case SIOCSIFPHYS:
                error = EOPNOTSUPP;
                break;

        default:
                error = EINVAL;
                break;
        }
        return (error);
}

static void
ng_eiface_init(void *xsc)
{
        priv_p sc = xsc;
        struct ifnet *ifp = sc->ifp;

        ifp->if_drv_flags |= IFF_DRV_RUNNING;
        ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
}

/*
 * We simply relay the packet to the "ether" hook, if it is connected.
 * We have been through the netgraph locking and are guaranteed to
 * be the only code running in this node at this time.
 */
static void
ng_eiface_start2(node_p node, hook_p hook, void *arg1, int arg2)
{
        struct ifnet *ifp = arg1;
        const priv_p priv = (priv_p)ifp->if_softc;
        int error = 0;
        struct mbuf *m;

        /* Check interface flags */

        if (!((ifp->if_flags & IFF_UP) &&
            (ifp->if_drv_flags & IFF_DRV_RUNNING)))
                return;

        for (;;) {
                /*
                 * Grab a packet to transmit.
                 */
                IF_DEQUEUE(&ifp->if_snd, m);

                /* If there's nothing to send, break. */
                if (m == NULL)
                        break;

                /* Peel the mbuf off any stale tags */
                m_tag_delete_chain(m, NULL);

                /*
                 * Berkeley packet filter.
                 * Pass packet to bpf if there is a listener.
                 * XXX is this safe? locking?
                 */
                BPF_MTAP(ifp, m);

                if (ifp->if_flags & IFF_MONITOR) {
                        if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
                        m_freem(m);
                        continue;
                }

                /*
                 * Send packet; if hook is not connected, mbuf will get
                 * freed.
                 */
                NG_OUTBOUND_THREAD_REF();
                CURVNET_SET_QUIET(priv->node->nd_vnet);
                NG_SEND_DATA_ONLY(error, priv->ether, m);
                CURVNET_RESTORE();
                NG_OUTBOUND_THREAD_UNREF();

                /* Update stats */
                if (error == 0)
                        if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
                else
                        if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
        }

        ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;

        return;
}

/*
 * This routine is called to deliver a packet out the interface.
 * We simply queue the netgraph version to be called when netgraph locking
 * allows it to happen.
 * Until we know what the rest of the networking code is doing for
 * locking, we don't know how we will interact with it.
 * Take comfort from the fact that the ifnet struct is part of our
 * private info and can't go away while we are queued.
 * [Though we don't know it is still there now....]
 * it is possible we don't gain anything from this because
 * we would like to get the mbuf and queue it as data
 * somehow, but we can't and if we did would we solve anything?
 */
static void
ng_eiface_start(struct ifnet *ifp)
{
        const priv_p priv = (priv_p)ifp->if_softc;

        /* Don't do anything if output is active */
        if (ifp->if_drv_flags & IFF_DRV_OACTIVE)
                return;

        ifp->if_drv_flags |= IFF_DRV_OACTIVE;

        if (ng_send_fn(priv->node, NULL, &ng_eiface_start2, ifp, 0) != 0)
                ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
}

#ifdef DEBUG
/*
 * Display an ioctl to the virtual interface
 */

static void
ng_eiface_print_ioctl(struct ifnet *ifp, int command, caddr_t data)
{
        char *str;

        switch (command & IOC_DIRMASK) {
        case IOC_VOID:
                str = "IO";
                break;
        case IOC_OUT:
                str = "IOR";
                break;
        case IOC_IN:
                str = "IOW";
                break;
        case IOC_INOUT:
                str = "IORW";
                break;
        default:
                str = "IO??";
        }
        log(LOG_DEBUG, "%s: %s('%c', %d, char[%d])\n",
            ifp->if_xname,
            str,
            IOCGROUP(command),
            command & 0xff,
            IOCPARM_LEN(command));
}
#endif /* DEBUG */

/*
 * ifmedia stuff
 */
static int
ng_eiface_mediachange(struct ifnet *ifp)
{
        const priv_p priv = (priv_p)ifp->if_softc;
        struct ifmedia *ifm = &priv->media;

        if (IFM_TYPE(ifm->ifm_media) != IFM_ETHER)
                return (EINVAL);
        if (IFM_SUBTYPE(ifm->ifm_media) == IFM_AUTO)
                ifp->if_baudrate = ifmedia_baudrate(IFM_ETHER | IFM_1000_T);
        else
                ifp->if_baudrate = ifmedia_baudrate(ifm->ifm_media);

        return (0);
}

static void
ng_eiface_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
{
        const priv_p priv = (priv_p)ifp->if_softc;
        struct ifmedia *ifm = &priv->media;

        if (ifm->ifm_cur->ifm_media == (IFM_ETHER | IFM_AUTO) &&
            (priv->link_status & IFM_ACTIVE))
                ifmr->ifm_active = IFM_ETHER | IFM_1000_T | IFM_FDX;
        else
                ifmr->ifm_active = ifm->ifm_cur->ifm_media;
        ifmr->ifm_status = priv->link_status;

        return;
}

/************************************************************************
                        NETGRAPH NODE STUFF
 ************************************************************************/

/*
 * Constructor for a node
 */
static int
ng_eiface_constructor(node_p node)
{
        struct ifnet *ifp;
        priv_p priv;
        struct ether_addr eaddr;

        /* Allocate node and interface private structures */
        priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
        ifp = priv->ifp = if_alloc(IFT_ETHER);

        /* Link them together */
        ifp->if_softc = priv;

        /* Get an interface unit number */
        priv->unit = alloc_unr(V_ng_eiface_unit);

        /* Link together node and private info */
        NG_NODE_SET_PRIVATE(node, priv);
        priv->node = node;

        /* Initialize interface structure */
        if_initname(ifp, NG_EIFACE_EIFACE_NAME, priv->unit);
        ifp->if_init = ng_eiface_init;
        ifp->if_output = ether_output;
        ifp->if_start = ng_eiface_start;
        ifp->if_ioctl = ng_eiface_ioctl;
        ifp->if_snd.ifq_maxlen = ifqmaxlen;
        ifp->if_flags = (IFF_SIMPLEX | IFF_BROADCAST | IFF_MULTICAST);
        ifp->if_capabilities = IFCAP_VLAN_MTU | IFCAP_JUMBO_MTU;
        ifp->if_capenable = IFCAP_VLAN_MTU | IFCAP_JUMBO_MTU;
        ifmedia_init(&priv->media, 0, ng_eiface_mediachange,
            ng_eiface_mediastatus);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_10_T, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_10_T | IFM_FDX, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_100_TX, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_100_TX | IFM_FDX, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_1000_T, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_1000_T | IFM_FDX, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_10G_T | IFM_FDX, 0, NULL);
        ifmedia_add(&priv->media, IFM_ETHER | IFM_AUTO, 0, NULL);
        ifmedia_set(&priv->media, IFM_ETHER | IFM_AUTO);
        priv->link_status = IFM_AVALID;

        /* Give this node the same name as the interface (if possible) */
        if (ng_name_node(node, ifp->if_xname) != 0)
                log(LOG_WARNING, "%s: can't acquire netgraph name\n",
                    ifp->if_xname);

        /* Attach the interface */
        ether_gen_addr(ifp, &eaddr);
        ether_ifattach(ifp, eaddr.octet);
        ifp->if_baudrate = ifmedia_baudrate(IFM_ETHER | IFM_1000_T);

        /* Done */
        return (0);
}

/*
 * Give our ok for a hook to be added
 */
static int
ng_eiface_newhook(node_p node, hook_p hook, const char *name)
{
        priv_p priv = NG_NODE_PRIVATE(node);
        struct ifnet *ifp = priv->ifp;

        if (strcmp(name, NG_EIFACE_HOOK_ETHER))
                return (EPFNOSUPPORT);
        if (priv->ether != NULL)
                return (EISCONN);
        priv->ether = hook;
        NG_HOOK_SET_PRIVATE(hook, &priv->ether);
        NG_HOOK_SET_TO_INBOUND(hook);

        priv->link_status |= IFM_ACTIVE;
        CURVNET_SET_QUIET(ifp->if_vnet);
        if_link_state_change(ifp, LINK_STATE_UP);
        CURVNET_RESTORE();

        return (0);
}

/*
 * Receive a control message
 */
static int
ng_eiface_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
        struct ifnet *const ifp = priv->ifp;
        struct ng_mesg *resp = NULL;
        int error = 0;
        struct ng_mesg *msg;

        NGI_GET_MSG(item, msg);
        switch (msg->header.typecookie) {
        case NGM_EIFACE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_EIFACE_SET:
                    {
                        if (msg->header.arglen != ETHER_ADDR_LEN) {
                                error = EINVAL;
                                break;
                        }
                        error = if_setlladdr(priv->ifp,
                            (u_char *)msg->data, ETHER_ADDR_LEN);
                        break;
                    }

                case NGM_EIFACE_GET_IFNAME:
                        NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        strlcpy(resp->data, ifp->if_xname, IFNAMSIZ);
                        break;

                case NGM_EIFACE_GET_IFADDRS:
                    {
                        struct epoch_tracker et;
                        struct ifaddr *ifa;
                        caddr_t ptr;
                        int buflen;

                        /* Determine size of response and allocate it */
                        buflen = 0;
                        NET_EPOCH_ENTER(et);
                        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                                buflen += SA_SIZE(ifa->ifa_addr);
                        NG_MKRESPONSE(resp, msg, buflen, M_NOWAIT);
                        if (resp == NULL) {
                                NET_EPOCH_EXIT(et);
                                error = ENOMEM;
                                break;
                        }

                        /* Add addresses */
                        ptr = resp->data;
                        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                                const int len = SA_SIZE(ifa->ifa_addr);

                                if (buflen < len) {
                                        log(LOG_ERR, "%s: len changed?\n",
                                            ifp->if_xname);
                                        break;
                                }
                                bcopy(ifa->ifa_addr, ptr, len);
                                ptr += len;
                                buflen -= len;
                        }
                        NET_EPOCH_EXIT(et);
                        break;
                    }

                default:
                        error = EINVAL;
                        break;
                } /* end of inner switch() */
                break;
        case NGM_FLOW_COOKIE:
                CURVNET_SET_QUIET(ifp->if_vnet);
                switch (msg->header.cmd) {
                case NGM_LINK_IS_UP:
                        priv->link_status |= IFM_ACTIVE;
                        if_link_state_change(ifp, LINK_STATE_UP);
                        break;
                case NGM_LINK_IS_DOWN:
                        priv->link_status &= ~IFM_ACTIVE;
                        if_link_state_change(ifp, LINK_STATE_DOWN);
                        break;
                default:
                        break;
                }
                CURVNET_RESTORE();
                break;
        default:
                error = EINVAL;
                break;
        }
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}

/*
 * Receive data from a hook. Pass the packet to the ether_input routine.
 */
static int
ng_eiface_rcvdata(hook_p hook, item_p item)
{
        const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        struct ifnet *const ifp = priv->ifp;
        struct mbuf *m;

        NGI_GET_M(item, m);
        NG_FREE_ITEM(item);

        if (!((ifp->if_flags & IFF_UP) &&
            (ifp->if_drv_flags & IFF_DRV_RUNNING))) {
                NG_FREE_M(m);
                return (ENETDOWN);
        }

        if (m->m_len < ETHER_HDR_LEN) {
                m = m_pullup(m, ETHER_HDR_LEN);
                if (m == NULL)
                        return (EINVAL);
        }

        /* Note receiving interface */
        m->m_pkthdr.rcvif = ifp;

        /* Update interface stats */
        if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);

        (*ifp->if_input)(ifp, m);

        /* Done */
        return (0);
}

/*
 * Shutdown processing.
 */
static int
ng_eiface_rmnode(node_p node)
{
        const priv_p priv = NG_NODE_PRIVATE(node);
        struct ifnet *const ifp = priv->ifp;

        /*
         * the ifnet may be in a different vnet than the netgraph node, 
         * hence we have to change the current vnet context here.
         */
        CURVNET_SET_QUIET(ifp->if_vnet);
        ether_ifdetach(ifp);
        ifmedia_removeall(&priv->media);
        if_free(ifp);
        CURVNET_RESTORE();
        free_unr(V_ng_eiface_unit, priv->unit);
        free(priv, M_NETGRAPH);
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(node);
        return (0);
}

/*
 * Hook disconnection
 */
static int
ng_eiface_disconnect(hook_p hook)
{
        const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));

        priv->ether = NULL;
        priv->link_status &= ~IFM_ACTIVE;
        CURVNET_SET_QUIET(priv->ifp->if_vnet);
        if_link_state_change(priv->ifp, LINK_STATE_DOWN);
        CURVNET_RESTORE();
        return (0);
}

/*
 * Handle loading and unloading for this node type.
 */
static int
ng_eiface_mod_event(module_t mod, int event, void *data)
{
        int error = 0;

        switch (event) {
        case MOD_LOAD:
        case MOD_UNLOAD:
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}

static void
vnet_ng_eiface_init(const void *unused)
{

        V_ng_eiface_unit = new_unrhdr(0, 0xffff, NULL);
}
VNET_SYSINIT(vnet_ng_eiface_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
    vnet_ng_eiface_init, NULL);

static void
vnet_ng_eiface_uninit(const void *unused)
{

        delete_unrhdr(V_ng_eiface_unit);
}
VNET_SYSUNINIT(vnet_ng_eiface_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
   vnet_ng_eiface_uninit, NULL);