/*
 * ng_tee.c
 *
 * Copyright (c) 1996-1999 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.
 *
 * Author: Julian Elischer <julian@freebsd.org>
 *
 * $FreeBSD: src/sys/netgraph/ng_tee.c,v 1.7.2.5 2002/07/02 23:44:03 archie Exp $
 * $Whistle: ng_tee.c,v 1.18 1999/11/01 09:24:52 julian Exp $
 */

/*
 * This node is like the tee(1) command and is useful for ``snooping.''
 * It has 4 hooks: left, right, left2right, and right2left. Data
 * entering from the right is passed to the left and duplicated on
 * right2left, and data entering from the left is passed to the right
 * and duplicated on left2right. Data entering from left2right is
 * sent to left, and data from right2left to right. 
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include "ng_tee.h"

/* Per hook info */
struct hookinfo {
        hook_p                  hook;
        struct ng_tee_hookstat  stats;
};

/* Per node info */
struct privdata {
        node_p                  node;
        struct hookinfo         left;
        struct hookinfo         right;
        struct hookinfo         left2right;
        struct hookinfo         right2left;
};
typedef struct privdata *sc_p;

/* Netgraph methods */
static ng_constructor_t ngt_constructor;
static ng_rcvmsg_t      ngt_rcvmsg;
static ng_shutdown_t    ngt_rmnode;
static ng_newhook_t     ngt_newhook;
static ng_rcvdata_t     ngt_rcvdata;
static ng_disconnect_t  ngt_disconnect;

/* Parse type for struct ng_tee_hookstat */
static const struct ng_parse_struct_field ng_tee_hookstat_type_fields[]
        = NG_TEE_HOOKSTAT_INFO;
static const struct ng_parse_type ng_tee_hookstat_type = {
        &ng_parse_struct_type,
        &ng_tee_hookstat_type_fields
};

/* Parse type for struct ng_tee_stats */
static const struct ng_parse_struct_field ng_tee_stats_type_fields[]
        = NG_TEE_STATS_INFO(&ng_tee_hookstat_type);
static const struct ng_parse_type ng_tee_stats_type = {
        &ng_parse_struct_type,
        &ng_tee_stats_type_fields
};

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_tee_cmds[] = {
        {
          NGM_TEE_COOKIE,
          NGM_TEE_GET_STATS,
          "getstats",
          NULL,
          &ng_tee_stats_type
        },
        {
          NGM_TEE_COOKIE,
          NGM_TEE_CLR_STATS,
          "clrstats",
          NULL,
          NULL
        },
        {
          NGM_TEE_COOKIE,
          NGM_TEE_GETCLR_STATS,
          "getclrstats",
          NULL,
          &ng_tee_stats_type
        },
        { 0 }
};

/* Netgraph type descriptor */
static struct ng_type ng_tee_typestruct = {
        NG_VERSION,
        NG_TEE_NODE_TYPE,
        NULL,
        ngt_constructor,
        ngt_rcvmsg,
        ngt_rmnode,
        ngt_newhook,
        NULL,
        NULL,
        ngt_rcvdata,
        ngt_rcvdata,
        ngt_disconnect,
        ng_tee_cmds
};
NETGRAPH_INIT(tee, &ng_tee_typestruct);

/*
 * Node constructor
 */
static int
ngt_constructor(node_p *nodep)
{
        sc_p privdata;
        int error = 0;

        privdata = kmalloc(sizeof(*privdata), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (privdata == NULL)
                return (ENOMEM);

        if ((error = ng_make_node_common(&ng_tee_typestruct, nodep))) {
                kfree(privdata, M_NETGRAPH);
                return (error);
        }
        (*nodep)->private = privdata;
        privdata->node = *nodep;
        return (0);
}

/*
 * Add a hook
 */
static int
ngt_newhook(node_p node, hook_p hook, const char *name)
{
        const sc_p sc = node->private;

        if (strcmp(name, NG_TEE_HOOK_RIGHT) == 0) {
                sc->right.hook = hook;
                bzero(&sc->right.stats, sizeof(sc->right.stats));
                hook->private = &sc->right;
        } else if (strcmp(name, NG_TEE_HOOK_LEFT) == 0) {
                sc->left.hook = hook;
                bzero(&sc->left.stats, sizeof(sc->left.stats));
                hook->private = &sc->left;
        } else if (strcmp(name, NG_TEE_HOOK_RIGHT2LEFT) == 0) {
                sc->right2left.hook = hook;
                bzero(&sc->right2left.stats, sizeof(sc->right2left.stats));
                hook->private = &sc->right2left;
        } else if (strcmp(name, NG_TEE_HOOK_LEFT2RIGHT) == 0) {
                sc->left2right.hook = hook;
                bzero(&sc->left2right.stats, sizeof(sc->left2right.stats));
                hook->private = &sc->left2right;
        } else
                return (EINVAL);
        return (0);
}

/*
 * Receive a control message
 */
static int
ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
           struct ng_mesg **rptr)
{
        const sc_p sc = node->private;
        struct ng_mesg *resp = NULL;
        int error = 0;

        switch (msg->header.typecookie) {
        case NGM_TEE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_TEE_GET_STATS:
                case NGM_TEE_CLR_STATS:
                case NGM_TEE_GETCLR_STATS:
                    {
                        struct ng_tee_stats *stats;

                        if (msg->header.cmd != NGM_TEE_CLR_STATS) {
                                NG_MKRESPONSE(resp, msg,
                                    sizeof(*stats), M_NOWAIT);
                                if (resp == NULL) {
                                        error = ENOMEM;
                                        goto done;
                                }
                                stats = (struct ng_tee_stats *)resp->data;
                                bcopy(&sc->right.stats, &stats->right,
                                    sizeof(stats->right));
                                bcopy(&sc->left.stats, &stats->left,
                                    sizeof(stats->left));
                                bcopy(&sc->right2left.stats, &stats->right2left,
                                    sizeof(stats->right2left));
                                bcopy(&sc->left2right.stats, &stats->left2right,
                                    sizeof(stats->left2right));
                        }
                        if (msg->header.cmd != NGM_TEE_GET_STATS) {
                                bzero(&sc->right.stats,
                                    sizeof(sc->right.stats));
                                bzero(&sc->left.stats,
                                    sizeof(sc->left.stats));
                                bzero(&sc->right2left.stats,
                                    sizeof(sc->right2left.stats));
                                bzero(&sc->left2right.stats,
                                    sizeof(sc->left2right.stats));
                        }
                        break;
                    }
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        if (rptr)
                *rptr = resp;
        else if (resp)
                kfree(resp, M_NETGRAPH);

done:
        kfree(msg, M_NETGRAPH);
        return (error);
}

/*
 * Receive data on a hook
 *
 * If data comes in the right link send a copy out right2left, and then
 * send the original onwards out through the left link.
 * Do the opposite for data coming in from the left link.
 * Data coming in right2left or left2right is forwarded
 * on through the appropriate destination hook as if it had come
 * from the other side.
 */
static int
ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
{
        const sc_p sc = hook->node->private;
        struct hookinfo *const hinfo = (struct hookinfo *) hook->private;
        struct hookinfo *dest;
        struct hookinfo *dup;
        int error = 0;

        /* Which hook? */
        if (hinfo == &sc->left) {
                dup = &sc->left2right;
                dest = &sc->right;
        } else if (hinfo == &sc->right) {
                dup = &sc->right2left;
                dest = &sc->left;
        } else if (hinfo == &sc->right2left) {
                dup = NULL;
                dest = &sc->right;
        } else if (hinfo == &sc->left2right) {
                dup = NULL;
                dest = &sc->left;
        } else
                panic("%s: no hook!", __func__);

        /* Update stats on incoming hook */
        hinfo->stats.inOctets += m->m_pkthdr.len;
        hinfo->stats.inFrames++;

        /* Duplicate packet and meta info if requried */
        if (dup != NULL) {
                struct mbuf *m2;
                meta_p meta2;

                /* Copy packet */
                m2 = m_dup(m, M_NOWAIT);
                if (m2 == NULL) {
                        NG_FREE_DATA(m, meta);
                        return (ENOBUFS);
                }

                /* Copy meta info */
                if (meta != NULL) {
                        meta2 = kmalloc(meta->used_len, M_NETGRAPH, M_NOWAIT);
                        if (meta2 == NULL) {
                                m_freem(m2);
                                NG_FREE_DATA(m, meta);
                                return (ENOMEM);
                        }
                        bcopy(meta, meta2, meta->used_len);
                        meta2->allocated_len = meta->used_len;
                } else
                        meta2 = NULL;

                /* Deliver duplicate */
                dup->stats.outOctets += m->m_pkthdr.len;
                dup->stats.outFrames++;
                NG_SEND_DATA(error, dup->hook, m2, meta2);
        }

        /* Deliver frame out destination hook */
        dest->stats.outOctets += m->m_pkthdr.len;
        dest->stats.outFrames++;
        NG_SEND_DATA(error, dest->hook, m, meta);
        return (error);
}

/*
 * Shutdown processing
 *
 * This is tricky. If we have both a left and right hook, then we
 * probably want to extricate ourselves and leave the two peers
 * still linked to each other. Otherwise we should just shut down as
 * a normal node would.
 *
 * To keep the scope of info correct the routine to "extract" a node
 * from two links is in ng_base.c.
 */
static int
ngt_rmnode(node_p node)
{
        const sc_p privdata = node->private;

        node->flags |= NG_INVALID;
        if (privdata->left.hook && privdata->right.hook)
                ng_bypass(privdata->left.hook, privdata->right.hook);
        ng_cutlinks(node);
        ng_unname(node);
        node->private = NULL;
        ng_unref(privdata->node);
        kfree(privdata, M_NETGRAPH);
        return (0);
}

/*
 * Hook disconnection
 */
static int
ngt_disconnect(hook_p hook)
{
        struct hookinfo *const hinfo = (struct hookinfo *) hook->private;

        KASSERT(hinfo != NULL, ("%s: null info", __func__));
        hinfo->hook = NULL;
        if (hook->node->numhooks == 0)
                ng_rmnode(hook->node);
        return (0);
}