sys/netgraph/socket/ng_socket.c

root/sys/netgraph/socket/ng_socket.c

/*
 * ng_socket.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_socket.c,v 1.11.2.6 2002/07/02 22:17:18 archie Exp $
 * $Whistle: ng_socket.c,v 1.28 1999/11/01 09:24:52 julian Exp $
 */

/*
 * Netgraph socket nodes
 *
 * There are two types of netgraph sockets, control and data.
 * Control sockets have a netgraph node, but data sockets are
 * parasitic on control sockets, and have no node of their own.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/caps.h>
#include <sys/domain.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/filedesc.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#ifdef NOTYET
#include <sys/vnode.h>
#endif

#include <sys/thread2.h>
#include <sys/socketvar2.h>
#include <sys/msgport2.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include "ng_socketvar.h"
#include "ng_socket.h"

/*
 * It's Ascii-art time!
 *   +-------------+   +-------------+
 *   |socket  (ctl)|   |socket (data)|
 *   +-------------+   +-------------+
 *          ^                 ^
 *          |                 |
 *          v                 v
 *    +-----------+     +-----------+
 *    |pcb   (ctl)|     |pcb  (data)|
 *    +-----------+     +-----------+
 *          ^                 ^
 *          |                 |
 *          v                 v
 *      +--------------------------+
 *      |   Socket type private    |
 *      |       data               |
 *      +--------------------------+
 *                   ^
 *                   |
 *                   v
 *           +----------------+
 *           | struct ng_node |
 *           +----------------+
 */

/* Netgraph node methods */
static ng_constructor_t ngs_constructor;
static ng_rcvmsg_t      ngs_rcvmsg;
static ng_shutdown_t    ngs_rmnode;
static ng_newhook_t     ngs_newhook;
static ng_rcvdata_t     ngs_rcvdata;
static ng_disconnect_t  ngs_disconnect;

/* Internal methods */
static int      ng_attach_data(struct socket *so);
static int      ng_attach_cntl(struct socket *so);
static int      ng_attach_common(struct socket *so, int type);
static void     ng_detach_common(struct ngpcb *pcbp, int type);
/*static int    ng_internalize(struct mbuf *m, struct thread *td); */

static int      ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp);
static int      ng_connect_cntl(struct sockaddr *nam, struct ngpcb *pcbp);
static int      ng_bind(struct sockaddr *nam, struct ngpcb *pcbp);

static int      ngs_mod_event(module_t mod, int event, void *data);
static int      ship_msg(struct ngpcb *pcbp, struct ng_mesg *msg,
                        struct sockaddr_ng *addr);

/* Netgraph type descriptor */
static struct ng_type typestruct = {
        NG_VERSION,
        NG_SOCKET_NODE_TYPE,
        ngs_mod_event,
        ngs_constructor,
        ngs_rcvmsg,
        ngs_rmnode,
        ngs_newhook,
        NULL,
        NULL,
        ngs_rcvdata,
        ngs_rcvdata,
        ngs_disconnect,
        NULL
};
NETGRAPH_INIT(socket, &typestruct);

/* Buffer space */
static u_long ngpdg_sendspace = 20 * 1024;      /* really max datagram size */
static u_long ngpdg_recvspace = 20 * 1024;

/* List of all sockets */
LIST_HEAD(, ngpcb) ngsocklist;

#define sotongpcb(so) ((struct ngpcb *)(so)->so_pcb)

/* If getting unexplained errors returned, set this to "Debugger("X"); */
#ifndef TRAP_ERROR
#define TRAP_ERROR
#endif

/***************************************************************
        Control sockets
***************************************************************/

static void
ngc_attach(netmsg_t msg)
{
        struct socket *so = msg->attach.base.nm_so;
        struct pru_attach_info *ai = msg->attach.nm_ai;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (caps_priv_check(ai->p_ucred,
                            SYSCAP_RESTRICTEDROOT | __SYSCAP_NULLCRED) != 0)
        {
                error = EPERM;
        }
        else if (pcbp != NULL)
                error = EISCONN;
        else
                error = ng_attach_cntl(so);
        lwkt_replymsg(&msg->attach.base.lmsg, error);
}

static void
ngc_detach(netmsg_t msg)
{
        struct socket *so = msg->detach.base.nm_so;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp) {
                ng_detach_common(pcbp, NG_CONTROL);
                error = 0;
        } else {
                error = EINVAL;
        }
        lwkt_replymsg(&msg->detach.base.lmsg, error);
}

static void
ngc_send(netmsg_t msg)
{
        struct socket *so = msg->send.base.nm_so;
        struct mbuf *m = msg->send.nm_m;
        struct sockaddr *addr = msg->send.nm_addr;
        struct mbuf *control = msg->send.nm_control;
        struct ngpcb *const pcbp = sotongpcb(so);
        struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
        struct ng_mesg *resp;
        struct mbuf *m0;
        char *xmsg, *path = NULL;
        int len;
        int error = 0;

        if (pcbp == NULL) {
                error = EINVAL;
                goto release;
        }
#ifdef  NOTYET
        if (control && (error = ng_internalize(control, p))) {
                if (pcbp->sockdata == NULL) {
                        error = ENOTCONN;
                        goto release;
                }
        }
#else   /* NOTYET */
        if (control) {
                error = EINVAL;
                goto release;
        }
#endif  /* NOTYET */

        /* Require destination as there may be >= 1 hooks on this node */
        if (addr == NULL) {
                error = EDESTADDRREQ;
                goto release;
        }

        /* Allocate an expendable buffer for the path, chop off
         * the sockaddr header, and make sure it's NUL terminated */
        len = sap->sg_len - 2;
        path = kmalloc(len + 1, M_NETGRAPH, M_WAITOK);
        bcopy(sap->sg_data, path, len);
        path[len] = '\0';

        /* Move the actual message out of mbufs into a linear buffer.
         * Start by adding up the size of the data. (could use mh_len?) */
        for (len = 0, m0 = m; m0 != NULL; m0 = m0->m_next)
                len += m0->m_len;

        /* Move the data into a linear buffer as well. Messages are not
         * delivered in mbufs. */
        xmsg = kmalloc(len + 1, M_NETGRAPH, M_WAITOK);
        m_copydata(m, 0, len, xmsg);

        /* The callee will free the xmsg when done. The addr is our business. */
        error = ng_send_msg(pcbp->sockdata->node,
                            (struct ng_mesg *) xmsg, path, &resp);

        /* If the callee responded with a synchronous response, then put it
         * back on the receive side of the socket; sap is source address. */
        if (error == 0 && resp != NULL)
                error = ship_msg(pcbp, resp, sap);

release:
        if (path != NULL)
                kfree(path, M_NETGRAPH);
        if (control != NULL)
                m_freem(control);
        if (m != NULL)
                m_freem(m);
        lwkt_replymsg(&msg->send.base.lmsg, error);
}

static void
ngc_bind(netmsg_t msg)
{
        struct socket *so = msg->bind.base.nm_so;
        struct sockaddr *nam = msg->bind.nm_nam;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp)
                error = ng_bind(nam, pcbp);
        else
                error = EINVAL;
        lwkt_replymsg(&msg->bind.base.lmsg, error);
}

static void
ngc_connect(netmsg_t msg)
{
        struct socket *so = msg->connect.base.nm_so;
        struct sockaddr *nam = msg->connect.nm_nam;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp)
                error = ng_connect_cntl(nam, pcbp);
        else
                error = EINVAL;
        lwkt_replymsg(&msg->connect.base.lmsg, error);
}

/***************************************************************
        Data sockets
***************************************************************/

static void
ngd_attach(netmsg_t msg)
{
        struct socket *so = msg->attach.base.nm_so;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp)
                error = EISCONN;
        else
                error = ng_attach_data(so);
        lwkt_replymsg(&msg->connect.base.lmsg, error);
}

static void
ngd_detach(netmsg_t msg)
{
        struct socket *so = msg->detach.base.nm_so;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp) {
                ng_detach_common(pcbp, NG_DATA);
                error = 0;
        } else {
                error = EINVAL;
        }
        lwkt_replymsg(&msg->detach.base.lmsg, error);
}

static void
ngd_send(netmsg_t msg)
{
        struct socket *so = msg->send.base.nm_so;
        struct mbuf *m = msg->send.nm_m;
        struct sockaddr *addr = msg->send.nm_addr;
        struct mbuf *control = msg->send.nm_control;
        struct ngpcb *const pcbp = sotongpcb(so);
        struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
        meta_p  mp = NULL;
        int     len, error;
        hook_p  hook = NULL;
        char    hookname[NG_HOOKSIZ];

        if ((pcbp == NULL) || (control != NULL)) {
                error = EINVAL;
                goto release;
        }
        if (pcbp->sockdata == NULL) {
                error = ENOTCONN;
                goto release;
        }
        /*
         * If the user used any of these ways to not specify an address
         * then handle specially.
         */
        if ((sap == NULL)
            || ((len = sap->sg_len - 2) <= 0)
            || (*sap->sg_data == '\0')) {
                if (pcbp->sockdata->node->numhooks != 1) {
                        error = EDESTADDRREQ;
                        goto release;
                }
                /*
                 * if exactly one hook exists, just use it.
                 * Special case to allow write(2) to work on an ng_socket.
                 */
                hook = LIST_FIRST(&pcbp->sockdata->node->hooks);
        } else {
                if (len >= NG_HOOKSIZ) {
                        error = EINVAL;
                        goto release;
                }

                /*
                 * chop off the sockaddr header, and make sure it's NUL
                 * terminated
                 */
                bcopy(sap->sg_data, hookname, len);
                hookname[len] = '\0';

                /* Find the correct hook from 'hookname' */
                LIST_FOREACH(hook, &pcbp->sockdata->node->hooks, hooks) {
                        if (strcmp(hookname, hook->name) == 0)
                                break;
                }
                if (hook == NULL)
                        error = EHOSTUNREACH;
        }

        /* Send data (OK if hook is NULL) */
        NG_SEND_DATA(error, hook, m, mp);       /* makes m NULL */

release:
        if (control != NULL)
                m_freem(control);
        if (m != NULL)
                m_freem(m);
        lwkt_replymsg(&msg->send.base.lmsg, error);
}

static void
ngd_connect(netmsg_t msg)
{
        struct socket *so = msg->connect.base.nm_so;
        struct sockaddr *nam = msg->connect.nm_nam;
        struct ngpcb *const pcbp = sotongpcb(so);
        int error;

        if (pcbp) {
                error = ng_connect_data(nam, pcbp);
        } else {
                error = EINVAL;
        }
        lwkt_replymsg(&msg->connect.base.lmsg, error);
}

/*
 * Used for both data and control sockets
 */
static void
ng_setsockaddr(netmsg_t msg)
{
        struct socket *so = msg->sockaddr.base.nm_so;
        struct sockaddr **addr = msg->sockaddr.nm_nam;
        struct ngpcb *pcbp;
        struct sockaddr_ng *sg;
        int sg_len, namelen;
        int error;

        /* Why isn't sg_data a `char[1]' ? :-( */
        sg_len = sizeof(struct sockaddr_ng) - sizeof(sg->sg_data) + 1;

        crit_enter();
        pcbp = sotongpcb(so);
        if ((pcbp == NULL) || (pcbp->sockdata == NULL)) {
                crit_exit();
                error = EINVAL;
                goto out;
        }

        namelen = 0;            /* silence compiler ! */

        if (pcbp->sockdata->node->name != NULL)
                sg_len += namelen = strlen(pcbp->sockdata->node->name);

        sg = kmalloc(sg_len, M_SONAME, M_WAITOK | M_ZERO);

        if (pcbp->sockdata->node->name != NULL)
                bcopy(pcbp->sockdata->node->name, sg->sg_data, namelen);
        crit_exit();

        sg->sg_len = sg_len;
        sg->sg_family = AF_NETGRAPH;
        *addr = (struct sockaddr *)sg;
        error = 0;
out:
        lwkt_replymsg(&msg->sockaddr.base.lmsg, error);
}

/*
 * Attach a socket to it's protocol specific partner.
 * For a control socket, actually create a netgraph node and attach
 * to it as well.
 */

static int
ng_attach_cntl(struct socket *so)
{
        struct ngsock *privdata;
        struct ngpcb *pcbp;
        int error;

        /* Setup protocol control block */
        if ((error = ng_attach_common(so, NG_CONTROL)) != 0)
                return (error);
        pcbp = sotongpcb(so);

        /* Allocate node private info */
        privdata = kmalloc(sizeof(*privdata), M_NETGRAPH, M_WAITOK | M_ZERO);

        /* Make the generic node components */
        if ((error = ng_make_node_common(&typestruct, &privdata->node)) != 0) {
                kfree(privdata, M_NETGRAPH);
                ng_detach_common(pcbp, NG_CONTROL);
                return (error);
        }
        privdata->node->private = privdata;

        /* Link the pcb and the node private data */
        privdata->ctlsock = pcbp;
        pcbp->sockdata = privdata;
        privdata->refs++;
        return (0);
}

static int
ng_attach_data(struct socket *so)
{
        return(ng_attach_common(so, NG_DATA));
}

/*
 * Set up a socket protocol control block.
 * This code is shared between control and data sockets.
 */
static int
ng_attach_common(struct socket *so, int type)
{
        struct ngpcb *pcbp;
        int error;

        /* Standard socket setup stuff */
        error = soreserve(so, ngpdg_sendspace, ngpdg_recvspace, NULL);
        if (error)
                return (error);

        /* Allocate the pcb */
        pcbp = kmalloc(sizeof(*pcbp), M_PCB, M_WAITOK | M_ZERO);
        pcbp->type = type;

        /* Link the pcb and the socket */
        soreference(so);
        so->so_pcb = (caddr_t) pcbp;
        pcbp->ng_socket = so;

        /* Add the socket to linked list */
        LIST_INSERT_HEAD(&ngsocklist, pcbp, socks);
        return (0);
}

/*
 * Disassociate the socket from it's protocol specific
 * partner. If it's attached to a node's private data structure,
 * then unlink from that too. If we were the last socket attached to it,
 * then shut down the entire node. Shared code for control and data sockets.
 */
static void
ng_detach_common(struct ngpcb *pcbp, int which)
{
        struct ngsock *sockdata;
        struct socket *so;

        if (pcbp->sockdata) {
                sockdata = pcbp->sockdata;
                pcbp->sockdata = NULL;
                switch (which) {
                case NG_CONTROL:
                        sockdata->ctlsock = NULL;
                        break;
                case NG_DATA:
                        sockdata->datasock = NULL;
                        break;
                default:
                        panic(__func__);
                }
                if ((--sockdata->refs == 0) && (sockdata->node != NULL))
                        ng_rmnode(sockdata->node);
        }
        so = pcbp->ng_socket;
        so->so_pcb = NULL;
        pcbp->ng_socket = NULL;
        sofree(so);             /* remove pcb ref */

        LIST_REMOVE(pcbp, socks);
        kfree(pcbp, M_PCB);
}

#ifdef NOTYET
/*
 * File descriptors can be passed into a AF_NETGRAPH socket.
 * Note, that file descriptors cannot be passed OUT.
 * Only character device descriptors are accepted.
 * Character devices are useful to connect a graph to a device,
 * which after all is the purpose of this whole system.
 */
static int
ng_internalize(struct mbuf *control, struct thread *td)
{
        struct filedesc *fdp = p->p_fd;
        const struct cmsghdr *cm = mtod(control, const struct cmsghdr *);
        struct file *fp;
        struct vnode *vn;
        int oldfds;
        int fd;

        if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
            cm->cmsg_len != control->m_len) {
                TRAP_ERROR;
                return (EINVAL);
        }

        /* Check there is only one FD. XXX what would more than one signify? */
        oldfds = (cm->cmsg_len - sizeof(*cm)) / sizeof(int);
        if (oldfds != 1) {
                TRAP_ERROR;
                return (EINVAL);
        }

        /* Check that the FD given is legit. and change it to a pointer to a
         * struct file. */
        fd = *(int *) (cm + 1);
        if ((unsigned) fd >= fdp->fd_nfiles
            || (fp = fdp->fd_files[fd].fp) == NULL) {
                return (EBADF);
        }

        /* Depending on what kind of resource it is, act differently. For
         * devices, we treat it as a file. For a AF_NETGRAPH socket,
         * shortcut straight to the node. */
        switch (fp->f_type) {
        case DTYPE_VNODE:
                vn = (struct vnode *) fp->f_data;
                if (vn && (vn->v_type == VCHR)) {
                        /* for a VCHR, actually reference the FILE */
                        fhold(fp);
                        /* XXX then what :) */
                        /* how to pass on to other modules? */
                } else {
                        TRAP_ERROR;
                        return (EINVAL);
                }
                break;
        default:
                TRAP_ERROR;
                return (EINVAL);
        }
        return (0);
}
#endif  /* NOTYET */

/*
 * Connect the data socket to a named control socket node.
 */
static int
ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp)
{
        struct sockaddr_ng *sap;
        node_p farnode;
        struct ngsock *sockdata;
        int error;

        /* If we are already connected, don't do it again */
        if (pcbp->sockdata != NULL)
                return (EISCONN);

        /* Find the target (victim) and check it doesn't already have a data
         * socket. Also check it is a 'socket' type node. */
        sap = (struct sockaddr_ng *) nam;
        if ((error = ng_path2node(NULL, sap->sg_data, &farnode, NULL)))
                return (error);

        if (strcmp(farnode->type->name, NG_SOCKET_NODE_TYPE) != 0)
                return (EINVAL);
        sockdata = farnode->private;
        if (sockdata->datasock != NULL)
                return (EADDRINUSE);

        /* Link the PCB and the private data struct. and note the extra
         * reference */
        sockdata->datasock = pcbp;
        pcbp->sockdata = sockdata;
        sockdata->refs++;
        return (0);
}

/*
 * Connect the existing control socket node to a named node:hook.
 * The hook we use on this end is the same name as the remote node name.
 */
static int
ng_connect_cntl(struct sockaddr *nam, struct ngpcb *pcbp)
{
        struct ngsock *const sockdata = pcbp->sockdata;
        struct sockaddr_ng *sap;
        char *node, *hook;
        node_p farnode;
        int rtn, error;

        sap = (struct sockaddr_ng *) nam;
        rtn = ng_path_parse(sap->sg_data, &node, NULL, &hook);
        if (rtn < 0 || node == NULL || hook == NULL) {
                TRAP_ERROR;
                return (EINVAL);
        }
        farnode = ng_findname(sockdata->node, node);
        if (farnode == NULL) {
                TRAP_ERROR;
                return (EADDRNOTAVAIL);
        }

        /* Connect, using a hook name the same as the far node name. */
        error = ng_con_nodes(sockdata->node, node, farnode, hook);
        return error;
}

/*
 * Binding a socket means giving the corresponding node a name
 */
static int
ng_bind(struct sockaddr *nam, struct ngpcb *pcbp)
{
        struct ngsock *const sockdata = pcbp->sockdata;
        struct sockaddr_ng *const sap = (struct sockaddr_ng *) nam;

        if (sockdata == NULL) {
                TRAP_ERROR;
                return (EINVAL);
        }
        if (sap->sg_len < 3 || sap->sg_data[sap->sg_len - 3] != '\0') {
                TRAP_ERROR;
                return (EINVAL);
        }
        return (ng_name_node(sockdata->node, sap->sg_data));
}

/*
 * Take a message and pass it up to the control socket associated
 * with the node.
 */
static int
ship_msg(struct ngpcb *pcbp, struct ng_mesg *msg, struct sockaddr_ng *addr)
{
        struct socket *const so = pcbp->ng_socket;
        struct mbuf *mdata;
        int msglen;

        /* Copy the message itself into an mbuf chain */
        msglen = sizeof(struct ng_mesg) + msg->header.arglen;
        mdata = m_devget(msg, msglen, 0, NULL);

        /* Here we free the message, as we are the end of the line.
         * We need to do that regardless of whether we got mbufs. */
        kfree(msg, M_NETGRAPH);

        if (mdata == NULL) {
                TRAP_ERROR;
                return (ENOBUFS);
        }

        /* Send it up to the socket */
        lwkt_gettoken(&so->so_rcv.ssb_token);
        if (ssb_appendaddr(&so->so_rcv,
            (struct sockaddr *) addr, mdata, NULL) == 0) {
                soroverflow(so);
                lwkt_reltoken(&so->so_rcv.ssb_token);
                TRAP_ERROR;
                m_freem(mdata);
                return (ENOBUFS);
        }
        sorwakeup(so);
        lwkt_reltoken(&so->so_rcv.ssb_token);
        return (0);
}

/*
 * You can only create new nodes from the socket end of things.
 */
static int
ngs_constructor(node_p *nodep)
{
        return (EINVAL);
}

/*
 * We allow any hook to be connected to the node.
 * There is no per-hook private information though.
 */
static int
ngs_newhook(node_p node, hook_p hook, const char *name)
{
        hook->private = node->private;
        return (0);
}

/*
 * Incoming messages get passed up to the control socket.
 * Unless they are for us specifically (socket_type)
 */
static int
ngs_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
           struct ng_mesg **resp)
{
        struct ngsock *const sockdata = node->private;
        struct ngpcb *const pcbp = sockdata->ctlsock;
        struct sockaddr_ng *addr;
        int addrlen;
        int error = 0;

        /* Only allow mesgs to be passed if we have the control socket.
         * Data sockets can only support the generic messages. */
        if (pcbp == NULL) {
                TRAP_ERROR;
                return (EINVAL);
        }

        if (msg->header.typecookie == NGM_SOCKET_COOKIE) {
                switch (msg->header.cmd) {
                case NGM_SOCK_CMD_NOLINGER:
                        sockdata->flags |= NGS_FLAG_NOLINGER;
                        break;
                case NGM_SOCK_CMD_LINGER:
                        sockdata->flags &= ~NGS_FLAG_NOLINGER;
                        break;
                default:
                        error = EINVAL;         /* unknown command */
                }
                /* Free the message and return */
                kfree(msg, M_NETGRAPH);
                return(error);

        }
        /* Get the return address into a sockaddr */
        if ((retaddr == NULL) || (*retaddr == '\0'))
                retaddr = "";
        addrlen = strlen(retaddr);
        addr = kmalloc(addrlen + 4, M_NETGRAPH, M_NOWAIT);
        if (addr == NULL) {
                TRAP_ERROR;
                return (ENOMEM);
        }
        addr->sg_len = addrlen + 3;
        addr->sg_family = AF_NETGRAPH;
        bcopy(retaddr, addr->sg_data, addrlen);
        addr->sg_data[addrlen] = '\0';

        /* Send it up */
        error = ship_msg(pcbp, msg, addr);
        kfree(addr, M_NETGRAPH);
        return (error);
}

/*
 * Receive data on a hook
 */
static int
ngs_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
{
        struct ngsock *const sockdata = hook->node->private;
        struct ngpcb *const pcbp = sockdata->datasock;
        struct socket *so;
        struct sockaddr_ng *addr;
        char *addrbuf[NG_HOOKSIZ + 4];
        int addrlen;

        /* If there is no data socket, black-hole it */
        if (pcbp == NULL) {
                NG_FREE_DATA(m, meta);
                return (0);
        }
        so = pcbp->ng_socket;

        /* Get the return address into a sockaddr. */
        addrlen = strlen(hook->name);   /* <= NG_HOOKSIZ - 1 */
        addr = (struct sockaddr_ng *) addrbuf;
        addr->sg_len = addrlen + 3;
        addr->sg_family = AF_NETGRAPH;
        bcopy(hook->name, addr->sg_data, addrlen);
        addr->sg_data[addrlen] = '\0';

        /* We have no use for the meta data, free/clear it now. */
        NG_FREE_META(meta);

        /* Try to tell the socket which hook it came in on */
        lwkt_gettoken(&so->so_rcv.ssb_token);
        if (ssb_appendaddr(&so->so_rcv, (struct sockaddr *) addr, m, NULL) == 0) {
                soroverflow(so);
                lwkt_reltoken(&so->so_rcv.ssb_token);
                m_freem(m);
                TRAP_ERROR;
                return (ENOBUFS);
        }
        sorwakeup(so);
        lwkt_reltoken(&so->so_rcv.ssb_token);
        return (0);
}

/*
 * Hook disconnection
 *
 * For this type, removal of the last link destroys the node
 * if the NOLINGER flag is set.
 */
static int
ngs_disconnect(hook_p hook)
{
        struct ngsock *const sockdata = hook->node->private;

        if ((sockdata->flags & NGS_FLAG_NOLINGER )
            && (hook->node->numhooks == 0)) {
                ng_rmnode(hook->node);
        }
        return (0);
}

/*
 * Do local shutdown processing.
 * In this case, that involves making sure the socket
 * knows we should be shutting down.
 */
static int
ngs_rmnode(node_p node)
{
        struct ngsock *const sockdata = node->private;
        struct ngpcb *const dpcbp = sockdata->datasock;
        struct ngpcb *const pcbp = sockdata->ctlsock;

        ng_cutlinks(node);
        ng_unname(node);

        if (dpcbp != NULL) {
                soisdisconnected(dpcbp->ng_socket);
                dpcbp->sockdata = NULL;
                sockdata->datasock = NULL;
                sockdata->refs--;
        }
        if (pcbp != NULL) {
                soisdisconnected(pcbp->ng_socket);
                pcbp->sockdata = NULL;
                sockdata->ctlsock = NULL;
                sockdata->refs--;
        }
        node->private = NULL;
        ng_unref(node);
        kfree(sockdata, M_NETGRAPH);
        return (0);
}

/*
 * Control and data socket type descriptors
 */

static struct pr_usrreqs ngc_usrreqs = {
        .pru_abort = NULL,
        .pru_accept = pr_generic_notsupp,
        .pru_attach = ngc_attach,
        .pru_bind = ngc_bind,
        .pru_connect = ngc_connect,
        .pru_connect2 = pr_generic_notsupp,
        .pru_control = pr_generic_notsupp,
        .pru_detach = ngc_detach,
        .pru_disconnect = NULL,
        .pru_listen = pr_generic_notsupp,
        .pru_peeraddr = NULL,
        .pru_rcvd = pr_generic_notsupp,
        .pru_rcvoob = pr_generic_notsupp,
        .pru_send = ngc_send,
        .pru_sense = pru_sense_null,
        .pru_shutdown = NULL,
        .pru_sockaddr = ng_setsockaddr,
        .pru_sosend = sosend,
        .pru_soreceive = soreceive
};

static struct pr_usrreqs ngd_usrreqs = {
        .pru_abort = NULL,
        .pru_accept = pr_generic_notsupp,
        .pru_attach = ngd_attach,
        .pru_bind = NULL,
        .pru_connect = ngd_connect,
        .pru_connect2 = pr_generic_notsupp,
        .pru_control = pr_generic_notsupp,
        .pru_detach = ngd_detach,
        .pru_disconnect = NULL,
        .pru_listen = pr_generic_notsupp,
        .pru_peeraddr = NULL,
        .pru_rcvd = pr_generic_notsupp,
        .pru_rcvoob = pr_generic_notsupp,
        .pru_send = ngd_send,
        .pru_sense = pru_sense_null,
        .pru_shutdown = NULL,
        .pru_sockaddr = ng_setsockaddr,
        .pru_sosend = sosend,
        .pru_soreceive = soreceive
};

/*
 * Definitions of protocols supported in the NETGRAPH domain.
 */

extern struct domain ngdomain;          /* stop compiler warnings */

static struct protosw ngsw[] = {
    {
        .pr_type = SOCK_DGRAM,
        .pr_domain = &ngdomain,
        .pr_protocol = NG_CONTROL,
        .pr_flags = PR_ATOMIC | PR_ADDR /* | PR_RIGHTS */,
        .pr_usrreqs = &ngc_usrreqs
    },
    {
        .pr_type = SOCK_DGRAM,
        .pr_domain = &ngdomain,
        .pr_protocol = NG_DATA,
        .pr_flags = PR_ATOMIC | PR_ADDR,
        .pr_usrreqs = &ngd_usrreqs
    }
};

struct domain ngdomain = {
        .dom_family             = AF_NETGRAPH,
        .dom_name               = "netgraph",
        .dom_protosw            = ngsw,
        .dom_protoswNPROTOSW    = &ngsw[NELEM(ngsw)],
};

/*
 * Handle loading and unloading for this node type
 * This is to handle auxiliary linkages (e.g protocol domain addition).
 */
static int
ngs_mod_event(module_t mod, int event, void *data)
{
        int error = 0;

        switch (event) {
        case MOD_LOAD:
                /* Register protocol domain */
                net_add_domain(&ngdomain);
                break;
        case MOD_UNLOAD:
                /* Insure there are no open netgraph sockets */
                if (!LIST_EMPTY(&ngsocklist)) {
                        error = EBUSY;
                        break;
                }

#ifdef NOTYET
                /* Unregister protocol domain XXX can't do this yet.. */
                if ((error = net_rm_domain(&ngdomain)) != 0)
                        break;
#else
                error = EBUSY;
#endif
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}

SYSCTL_INT(_net_graph, OID_AUTO, family, CTLFLAG_RD, 0, AF_NETGRAPH, "");
SYSCTL_NODE(_net_graph, OID_AUTO, data, CTLFLAG_RW, 0, "DATA");
SYSCTL_INT(_net_graph_data, OID_AUTO, proto, CTLFLAG_RD, 0, NG_DATA, "");
SYSCTL_NODE(_net_graph, OID_AUTO, control, CTLFLAG_RW, 0, "CONTROL");
SYSCTL_INT(_net_graph_control, OID_AUTO, proto, CTLFLAG_RD, 0, NG_CONTROL, "");
DragonflyBSD
