/*
 * ng_ether.c
 *
 * Copyright (c) 1996-2000 Whistle Communications, Inc.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Authors: Archie Cobbs <archie@freebsd.org>
 *          Julian Elischer <julian@freebsd.org>
 *
 * $FreeBSD: src/sys/netgraph/ng_ether.c,v 1.2.2.13 2002/07/02 20:10:25 archie Exp $
 */

/*
 * ng_ether(4) netgraph node type
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <sys/socket.h>
#include <sys/thread2.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/if_arp.h>
#include <net/if_var.h>
#include <net/ethernet.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include "ng_ether.h"

#define IFP2AC(IFP)  ((struct arpcom *)IFP)
#define IFP2NG(ifp)  (IFP2AC((ifp))->ac_netgraph)

/* Per-node private data */
struct private {
        struct ifnet    *ifp;           /* associated interface */
        hook_p          upper;          /* upper hook connection */
        hook_p          lower;          /* lower OR orphan hook connection */
        u_char          lowerOrphan;    /* whether lower is lower or orphan */
        u_char          autoSrcAddr;    /* always overwrite source address */
        u_char          promisc;        /* promiscuous mode enabled */
        u_long          hwassist;       /* hardware checksum capabilities */
};
typedef struct private *priv_p;

/* Functional hooks called from if_ethersubr.c */
static void     ng_ether_input(struct ifnet *ifp, struct mbuf **mp);
static void     ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m);
static int      ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
static void     ng_ether_attach(struct ifnet *ifp);
static void     ng_ether_detach(struct ifnet *ifp); 

/* Other functions */
static void     ng_ether_input2(node_p node, struct mbuf **mp);
static int      ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta);
static int      ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta);

/* Netgraph node methods */
static ng_constructor_t ng_ether_constructor;
static ng_rcvmsg_t      ng_ether_rcvmsg;
static ng_shutdown_t    ng_ether_rmnode;
static ng_newhook_t     ng_ether_newhook;
static ng_rcvdata_t     ng_ether_rcvdata;
static ng_disconnect_t  ng_ether_disconnect;
static int              ng_ether_mod_event(module_t mod, int event, void *data);

/* Parse type for an Ethernet address */
static ng_parse_t       ng_enaddr_parse;
static ng_unparse_t     ng_enaddr_unparse;
const struct ng_parse_type ng_ether_enaddr_type = {
        NULL,
        NULL,
        NULL,
        ng_enaddr_parse,
        ng_enaddr_unparse,
        NULL,                   /* no such thing as a "default" EN address */
        0
};

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_ether_cmdlist[] = {
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_GET_IFNAME,
          "getifname",
          NULL,
          &ng_parse_string_type
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_GET_IFINDEX,
          "getifindex",
          NULL,
          &ng_parse_int32_type
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_GET_ENADDR,
          "getenaddr",
          NULL,
          &ng_ether_enaddr_type
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_SET_ENADDR,
          "setenaddr",
          &ng_ether_enaddr_type,
          NULL
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_GET_PROMISC,
          "getpromisc",
          NULL,
          &ng_parse_int32_type
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_SET_PROMISC,
          "setpromisc",
          &ng_parse_int32_type,
          NULL
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_GET_AUTOSRC,
          "getautosrc",
          NULL,
          &ng_parse_int32_type
        },
        {
          NGM_ETHER_COOKIE,
          NGM_ETHER_SET_AUTOSRC,
          "setautosrc",
          &ng_parse_int32_type,
          NULL
        },
        { 0 }
};

static struct ng_type ng_ether_typestruct = {
        NG_VERSION,
        NG_ETHER_NODE_TYPE,
        ng_ether_mod_event,
        ng_ether_constructor,
        ng_ether_rcvmsg,
        ng_ether_rmnode,
        ng_ether_newhook,
        NULL,
        NULL,
        ng_ether_rcvdata,
        ng_ether_rcvdata,
        ng_ether_disconnect,
        ng_ether_cmdlist,
};
NETGRAPH_INIT(ether, &ng_ether_typestruct);

/******************************************************************
                    ETHERNET FUNCTION HOOKS
******************************************************************/

/*
 * Handle a packet that has come in on an interface. We get to
 * look at it here before any upper layer protocols do.
 */
static void
ng_ether_input(struct ifnet *ifp, struct mbuf **mp)
{
        const node_p node = IFP2NG(ifp);
        const priv_p priv = node->private;

        /* If "lower" hook not connected, let packet continue */
        if (priv->lower == NULL || priv->lowerOrphan)
                return;
        ng_ether_input2(node, mp);
}

/*
 * Handle a packet that has come in on an interface, and which
 * does not match any of our known protocols (an ``orphan'').
 */
static void
ng_ether_input_orphan(struct ifnet *ifp, struct mbuf *m)
{
        const node_p node = IFP2NG(ifp);
        const priv_p priv = node->private;

        /* If "orphan" hook not connected, let packet continue */
        if (priv->lower == NULL || !priv->lowerOrphan) {
                m_freem(m);
                return;
        }
        ng_ether_input2(node, &m);
        if (m != NULL)
                m_freem(m);
}

/*
 * Handle a packet that has come in on an interface.
 * The Ethernet header has already been detached from the mbuf,
 * so we have to put it back.
 *
 * NOTE: this function will get called at splimp()
 */
static void
ng_ether_input2(node_p node, struct mbuf **mp)
{
        const priv_p priv = node->private;
        meta_p meta = NULL;

        /* Send out lower/orphan hook */
        ng_queue_data(priv->lower, *mp, meta);
        *mp = NULL;
}

/*
 * Handle a packet that is going out on an interface.
 * The Ethernet header is already attached to the mbuf.
 */
static int
ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
{
        const node_p node = IFP2NG(ifp);
        const priv_p priv = node->private;
        meta_p meta = NULL;
        int error = 0;

        /* If "upper" hook not connected, let packet continue */
        if (priv->upper == NULL)
                return (0);

        /* Send it out "upper" hook */
        NG_SEND_DATA(error, priv->upper, *mp, meta);
        *mp = NULL;
        return (error);
}

/*
 * A new Ethernet interface has been attached.
 * Create a new node for it, etc.
 */
static void
ng_ether_attach(struct ifnet *ifp)
{
        char name[IFNAMSIZ + 1];
        priv_p priv;
        node_p node;

        /* Create node */
        KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __func__));
        strlcpy(name, ifp->if_xname, sizeof(name));
        if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
                log(LOG_ERR, "%s: can't %s for %s\n",
                    __func__, "create node", name);
                return;
        }

        /* Allocate private data */
        priv = kmalloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (priv == NULL) {
                log(LOG_ERR, "%s: can't %s for %s\n",
                    __func__, "allocate memory", name);
                ng_unref(node);
                return;
        }
        node->private = priv;
        priv->ifp = ifp;
        IFP2NG(ifp) = node;
        priv->autoSrcAddr = 1;
        priv->hwassist = ifp->if_hwassist;

        /* Try to give the node the same name as the interface */
        if (ng_name_node(node, name) != 0) {
                log(LOG_WARNING, "%s: can't name node %s\n",
                    __func__, name);
        }
}

/*
 * An Ethernet interface is being detached.
 * Destroy its node.
 */
static void
ng_ether_detach(struct ifnet *ifp)
{
        const node_p node = IFP2NG(ifp);
        priv_p priv;

        if (node == NULL)               /* no node (why not?), ignore */
                return;
        ng_rmnode(node);                /* break all links to other nodes */
        node->flags |= NG_INVALID;
        ng_unname(node);                /* free name (and its reference) */
        IFP2NG(ifp) = NULL;             /* detach node from interface */
        priv = node->private;           /* free node private info */
        bzero(priv, sizeof(*priv));
        kfree(priv, M_NETGRAPH);
        node->private = NULL;
        ng_unref(node);                 /* free node itself */
}

/******************************************************************
                    NETGRAPH NODE METHODS
******************************************************************/

/*
 * It is not possible or allowable to create a node of this type.
 * Nodes get created when the interface is attached (or, when
 * this node type's KLD is loaded).
 */
static int
ng_ether_constructor(node_p *nodep)
{
        return (EINVAL);
}

/*
 * Check for attaching a new hook.
 */
static  int
ng_ether_newhook(node_p node, hook_p hook, const char *name)
{
        const priv_p priv = node->private;
        u_char orphan = priv->lowerOrphan;
        hook_p *hookptr;

        /* Divert hook is an alias for lower */
        if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
                name = NG_ETHER_HOOK_LOWER;

        /* Which hook? */
        if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0)
                hookptr = &priv->upper;
        else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0) {
                hookptr = &priv->lower;
                orphan = 0;
        } else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0) {
                hookptr = &priv->lower;
                orphan = 1;
        } else
                return (EINVAL);

        /* Check if already connected (shouldn't be, but doesn't hurt) */
        if (*hookptr != NULL)
                return (EISCONN);

        /* Disable hardware checksums while 'upper' hook is connected */
        if (hookptr == &priv->upper)
                priv->ifp->if_hwassist = 0;

        /* OK */
        *hookptr = hook;
        priv->lowerOrphan = orphan;
        return (0);
}

/*
 * Receive an incoming control message.
 */
static int
ng_ether_rcvmsg(node_p node, struct ng_mesg *msg,
        const char *retaddr, struct ng_mesg **rptr)
{
        const priv_p priv = node->private;
        struct ng_mesg *resp = NULL;
        int error = 0;

        switch (msg->header.typecookie) {
        case NGM_ETHER_COOKIE:
                switch (msg->header.cmd) {
                case NGM_ETHER_GET_IFNAME:
                        NG_MKRESPONSE(resp, msg, IFNAMSIZ + 1, M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        strlcpy(resp->data, priv->ifp->if_xname, IFNAMSIZ);
                        break;
                case NGM_ETHER_GET_IFINDEX:
                        NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        *((u_int32_t *)resp->data) = priv->ifp->if_index;
                        break;
                case NGM_ETHER_GET_ENADDR:
                        NG_MKRESPONSE(resp, msg, ETHER_ADDR_LEN, M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        bcopy((IFP2AC(priv->ifp))->ac_enaddr,
                            resp->data, ETHER_ADDR_LEN);
                        break;
                case NGM_ETHER_SET_ENADDR:
                    {
                        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_ETHER_GET_PROMISC:
                        NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        *((u_int32_t *)resp->data) = priv->promisc;
                        break;
                case NGM_ETHER_SET_PROMISC:
                    {
                        u_char want;

                        if (msg->header.arglen != sizeof(u_int32_t)) {
                                error = EINVAL;
                                break;
                        }
                        want = !!*((u_int32_t *)msg->data);
                        if (want ^ priv->promisc) {
                                if ((error = ifpromisc(priv->ifp, want)) != 0)
                                        break;
                                priv->promisc = want;
                        }
                        break;
                    }
                case NGM_ETHER_GET_AUTOSRC:
                        NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        *((u_int32_t *)resp->data) = priv->autoSrcAddr;
                        break;
                case NGM_ETHER_SET_AUTOSRC:
                        if (msg->header.arglen != sizeof(u_int32_t)) {
                                error = EINVAL;
                                break;
                        }
                        priv->autoSrcAddr = !!*((u_int32_t *)msg->data);
                        break;
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        if (rptr)
                *rptr = resp;
        else if (resp != NULL)
                kfree(resp, M_NETGRAPH);
        kfree(msg, M_NETGRAPH);
        return (error);
}

/*
 * Receive data on a hook.
 */
static int
ng_ether_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
{
        const node_p node = hook->node;
        const priv_p priv = node->private;

        if (hook == priv->lower)
                return ng_ether_rcv_lower(node, m, meta);
        if (hook == priv->upper)
                return ng_ether_rcv_upper(node, m, meta);
        panic("%s: weird hook", __func__);
}

/*
 * Handle an mbuf received on the "lower" hook.
 */
static int
ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta)
{
        const priv_p priv = node->private;
        struct ifnet *const ifp = priv->ifp;
        int error;

        /* Discard meta info */
        NG_FREE_META(meta);

        /* Check whether interface is ready for packets */
        if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
                m_freem(m);
                return (ENETDOWN);
        }

        /* Make sure header is fully pulled up */
        if (m->m_pkthdr.len < sizeof(struct ether_header)) {
                m_freem(m);
                return (EINVAL);
        }
        if (m->m_len < sizeof(struct ether_header)
            && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
                return (ENOBUFS);

        /* Drop in the MAC address if desired */
        if (priv->autoSrcAddr) {

                /* Make the mbuf writable if it's not already */
                if (!M_WRITABLE(m)
                    && (m = m_pullup(m, sizeof(struct ether_header))) == NULL)
                        return (ENOBUFS);

                /* Overwrite source MAC address */
                bcopy((IFP2AC(ifp))->ac_enaddr,
                    mtod(m, struct ether_header *)->ether_shost,
                    ETHER_ADDR_LEN);
        }

        /* Send it on its way */
        error = ether_output_frame(ifp, m);
        return (error);
}

/*
 * Handle an mbuf received on the "upper" hook.
 */
static int
ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta)
{
        const priv_p priv = node->private;

        /* Discard meta info */
        NG_FREE_META(meta);

        /* Check length and pull off header */
        if (m->m_pkthdr.len < ETHER_HDR_LEN) {
                m_freem(m);
                return (EINVAL);
        }
        if (m->m_len < ETHER_HDR_LEN &&
            (m = m_pullup(m, ETHER_HDR_LEN)) == NULL)
                return (ENOBUFS);

        m->m_pkthdr.rcvif = priv->ifp;

        /* Route packet back in */
        ether_demux(m);
        return (0);
}

/*
 * Shutdown node. This resets the node but does not remove it.
 */
static int
ng_ether_rmnode(node_p node)
{
        const priv_p priv = node->private;

        ng_cutlinks(node);
        node->flags &= ~NG_INVALID;     /* bounce back to life */
        if (priv->promisc) {            /* disable promiscuous mode */
                ifpromisc(priv->ifp, 0);
                priv->promisc = 0;
        }
        priv->autoSrcAddr = 1;          /* reset auto-src-addr flag */
        return (0);
}

/*
 * Hook disconnection.
 */
static int
ng_ether_disconnect(hook_p hook)
{
        const priv_p priv = hook->node->private;

        if (hook == priv->upper) {
                priv->upper = NULL;
                priv->ifp->if_hwassist = priv->hwassist;  /* restore h/w csum */
        } else if (hook == priv->lower) {
                priv->lower = NULL;
                priv->lowerOrphan = 0;
        } else
                panic("%s: weird hook", __func__);
        if (hook->node->numhooks == 0)
                ng_rmnode(hook->node);  /* reset node */
        return (0);
}

static int
ng_enaddr_parse(const struct ng_parse_type *type,
        const char *s, int *const off, const u_char *const start,
        u_char *const buf, int *const buflen)
{
        char *eptr;
        u_long val;
        int i;

        if (*buflen < ETHER_ADDR_LEN)
                return (ERANGE);
        for (i = 0; i < ETHER_ADDR_LEN; i++) {
                val = strtoul(s + *off, &eptr, 16);
                if (val > 0xff || eptr == s + *off)
                        return (EINVAL);
                buf[i] = (u_char)val;
                *off = (eptr - s);
                if (i < ETHER_ADDR_LEN - 1) {
                        if (*eptr != ':')
                                return (EINVAL);
                        (*off)++;
                }
        }
        *buflen = ETHER_ADDR_LEN;
        return (0);
}

static int
ng_enaddr_unparse(const struct ng_parse_type *type,
        const u_char *data, int *off, char *cbuf, int cbuflen)
{
        int len;

        len = ksnprintf(cbuf, cbuflen, "%02x:%02x:%02x:%02x:%02x:%02x",
            data[*off], data[*off + 1], data[*off + 2],
            data[*off + 3], data[*off + 4], data[*off + 5]);
        if (len >= cbuflen)
                return (ERANGE);
        *off += ETHER_ADDR_LEN;
        return (0);
}

/******************************************************************
                        INITIALIZATION
******************************************************************/

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

        crit_enter();
        switch (event) {
        case MOD_LOAD:

                /* Register function hooks */
                if (ng_ether_attach_p != NULL) {
                        error = EEXIST;
                        break;
                }
                ng_ether_attach_p = ng_ether_attach;
                ng_ether_detach_p = ng_ether_detach;
                ng_ether_output_p = ng_ether_output;
                ng_ether_input_p = ng_ether_input;
                ng_ether_input_orphan_p = ng_ether_input_orphan;

                /* Create nodes for any already-existing Ethernet interfaces */
                ifnet_lock();
                TAILQ_FOREACH(ifp, &ifnetlist, if_link) {
                        if (ifp->if_type == IFT_ETHER ||
                            ifp->if_type == IFT_L2VLAN)
                                ng_ether_attach(ifp);
                }
                ifnet_unlock();
                break;

        case MOD_UNLOAD:

                /*
                 * Note that the base code won't try to unload us until
                 * all nodes have been removed, and that can't happen
                 * until all Ethernet interfaces are removed. In any
                 * case, we know there are no nodes left if the action
                 * is MOD_UNLOAD, so there's no need to detach any nodes.
                 */

                /* Unregister function hooks */
                ng_ether_attach_p = NULL;
                ng_ether_detach_p = NULL;
                ng_ether_output_p = NULL;
                ng_ether_input_p = NULL;
                ng_ether_input_orphan_p = NULL;
                break;

        default:
                error = EOPNOTSUPP;
                break;
        }
        crit_exit();
        return (error);
}