freebsd-dev/sys/netgraph/ng_gif.c
Robert Watson 77dfcdc445 Rework global locks for interface list and index management, correcting
several critical bugs, including race conditions and lock order issues:

Replace the single rwlock, ifnet_lock, with two locks, an rwlock and an
sxlock.  Either can be held to stablize the lists and indexes, but both
are required to write.  This allows the list to be held stable in both
network interrupt contexts and sleepable user threads across sleeping
memory allocations or device driver interactions.  As before, writes to
the interface list must occur from sleepable contexts.

Reviewed by:	bz, julian
MFC after:	3 days
2009-08-23 20:40:19 +00:00

604 lines
16 KiB
C

/*
* ng_gif.c
*/
/*-
* Copyright 2001 The Aerospace Corporation. 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. The name of The Aerospace Corporation may not be used to endorse or
* promote products derived from this software.
*
* THIS SOFTWARE IS PROVIDED BY THE AEROSPACE CORPORATION ``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 AEROSPACE CORPORATION 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.
*
*
* 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.
*
* $FreeBSD$
*/
/*
* ng_gif(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 <net/if.h>
#include <net/route.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/if_gif.h>
#include <net/vnet.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_gif.h>
#define IFP2NG(ifp) ((struct ng_node *)((struct gif_softc *)(ifp->if_softc))->gif_netgraph)
#define IFP2NG_SET(ifp, val) (((struct gif_softc *)(ifp->if_softc))->gif_netgraph = (val))
/* Per-node private data */
struct private {
struct ifnet *ifp; /* associated interface */
hook_p lower; /* lower OR orphan hook connection */
u_char lowerOrphan; /* whether lower is lower or orphan */
};
typedef struct private *priv_p;
/* Functional hooks called from if_gif.c */
static void ng_gif_input(struct ifnet *ifp, struct mbuf **mp, int af);
static void ng_gif_input_orphan(struct ifnet *ifp, struct mbuf *m, int af);
static void ng_gif_attach(struct ifnet *ifp);
static void ng_gif_detach(struct ifnet *ifp);
/* Other functions */
static void ng_gif_input2(node_p node, struct mbuf **mp, int af);
static int ng_gif_glue_af(struct mbuf **mp, int af);
static int ng_gif_rcv_lower(node_p node, struct mbuf *m);
/* Netgraph node methods */
static ng_constructor_t ng_gif_constructor;
static ng_rcvmsg_t ng_gif_rcvmsg;
static ng_shutdown_t ng_gif_shutdown;
static ng_newhook_t ng_gif_newhook;
static ng_connect_t ng_gif_connect;
static ng_rcvdata_t ng_gif_rcvdata;
static ng_disconnect_t ng_gif_disconnect;
static int ng_gif_mod_event(module_t mod, int event, void *data);
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_gif_cmdlist[] = {
{
NGM_GIF_COOKIE,
NGM_GIF_GET_IFNAME,
"getifname",
NULL,
&ng_parse_string_type
},
{
NGM_GIF_COOKIE,
NGM_GIF_GET_IFINDEX,
"getifindex",
NULL,
&ng_parse_int32_type
},
{ 0 }
};
static struct ng_type ng_gif_typestruct = {
.version = NG_ABI_VERSION,
.name = NG_GIF_NODE_TYPE,
.mod_event = ng_gif_mod_event,
.constructor = ng_gif_constructor,
.rcvmsg = ng_gif_rcvmsg,
.shutdown = ng_gif_shutdown,
.newhook = ng_gif_newhook,
.connect = ng_gif_connect,
.rcvdata = ng_gif_rcvdata,
.disconnect = ng_gif_disconnect,
.cmdlist = ng_gif_cmdlist,
};
MODULE_DEPEND(ng_gif, if_gif, 1,1,1);
NETGRAPH_INIT(gif, &ng_gif_typestruct);
/******************************************************************
GIF 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.
*
* NOTE: this function will get called at splimp()
*/
static void
ng_gif_input(struct ifnet *ifp, struct mbuf **mp, int af)
{
const node_p node = IFP2NG(ifp);
const priv_p priv = NG_NODE_PRIVATE(node);
/* If "lower" hook not connected, let packet continue */
if (priv->lower == NULL || priv->lowerOrphan)
return;
ng_gif_input2(node, mp, af);
}
/*
* Handle a packet that has come in on an interface, and which
* does not match any of our known protocols (an ``orphan'').
*
* NOTE: this function will get called at splimp()
*/
static void
ng_gif_input_orphan(struct ifnet *ifp, struct mbuf *m, int af)
{
const node_p node = IFP2NG(ifp);
const priv_p priv = NG_NODE_PRIVATE(node);
/* If "orphan" hook not connected, let packet continue */
if (priv->lower == NULL || !priv->lowerOrphan) {
m_freem(m);
return;
}
ng_gif_input2(node, &m, af);
if (m != NULL)
m_freem(m);
}
/*
* Handle a packet that has come in on a gif interface.
* Attach the address family to the mbuf for later use.
*
* NOTE: this function will get called at splimp()
*/
static void
ng_gif_input2(node_p node, struct mbuf **mp, int af)
{
const priv_p priv = NG_NODE_PRIVATE(node);
int error;
/* Glue address family on */
if ((error = ng_gif_glue_af(mp, af)) != 0)
return;
/* Send out lower/orphan hook */
NG_SEND_DATA_ONLY(error, priv->lower, *mp);
*mp = NULL;
}
/*
* A new gif interface has been attached.
* Create a new node for it, etc.
*/
static void
ng_gif_attach(struct ifnet *ifp)
{
priv_p priv;
node_p node;
/* Create node */
KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __func__));
if (ng_make_node_common(&ng_gif_typestruct, &node) != 0) {
log(LOG_ERR, "%s: can't %s for %s\n",
__func__, "create node", ifp->if_xname);
return;
}
/* Allocate private data */
priv = malloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
if (priv == NULL) {
log(LOG_ERR, "%s: can't %s for %s\n",
__func__, "allocate memory", ifp->if_xname);
NG_NODE_UNREF(node);
return;
}
NG_NODE_SET_PRIVATE(node, priv);
priv->ifp = ifp;
IFP2NG_SET(ifp, node);
/* Try to give the node the same name as the interface */
if (ng_name_node(node, ifp->if_xname) != 0) {
log(LOG_WARNING, "%s: can't name node %s\n",
__func__, ifp->if_xname);
}
}
/*
* An interface is being detached.
* REALLY Destroy its node.
*/
static void
ng_gif_detach(struct ifnet *ifp)
{
const node_p node = IFP2NG(ifp);
priv_p priv;
if (node == NULL) /* no node (why not?), ignore */
return;
priv = NG_NODE_PRIVATE(node);
NG_NODE_REALLY_DIE(node); /* Force real removal of node */
/*
* We can't assume the ifnet is still around when we run shutdown
* So zap it now. XXX We HOPE that anything running at this time
* handles it (as it should in the non netgraph case).
*/
IFP2NG_SET(ifp, NULL);
priv->ifp = NULL; /* XXX race if interrupted an output packet */
ng_rmnode_self(node); /* remove all netgraph parts */
}
/*
* Optimization for gluing the address family onto
* the front of an incoming packet.
*/
static int
ng_gif_glue_af(struct mbuf **mp, int af)
{
struct mbuf *m = *mp;
int error = 0;
sa_family_t tmp_af;
tmp_af = (sa_family_t) af;
/*
* XXX: should try to bring back some of the optimizations from
* ng_ether.c
*/
/*
* Doing anything more is likely to get more
* expensive than it's worth..
* it's probable that everything else is in one
* big lump. The next node will do an m_pullup()
* for exactly the amount of data it needs and
* hopefully everything after that will not
* need one. So let's just use M_PREPEND.
*/
M_PREPEND(m, sizeof (tmp_af), M_DONTWAIT);
if (m == NULL) {
error = ENOBUFS;
goto done;
}
#if 0
copy:
#endif
/* Copy header and return (possibly new) mbuf */
*mtod(m, sa_family_t *) = tmp_af;
#if 0
bcopy((caddr_t)&tmp_af, mtod(m, sa_family_t *), sizeof(tmp_af));
#endif
done:
*mp = m;
return error;
}
/******************************************************************
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_gif_constructor(node_p node)
{
return (EINVAL);
}
/*
* Check for attaching a new hook.
*/
static int
ng_gif_newhook(node_p node, hook_p hook, const char *name)
{
const priv_p priv = NG_NODE_PRIVATE(node);
u_char orphan = priv->lowerOrphan;
hook_p *hookptr;
/* Divert hook is an alias for lower */
if (strcmp(name, NG_GIF_HOOK_DIVERT) == 0)
name = NG_GIF_HOOK_LOWER;
/* Which hook? */
if (strcmp(name, NG_GIF_HOOK_LOWER) == 0) {
hookptr = &priv->lower;
orphan = 0;
} else if (strcmp(name, NG_GIF_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);
/* OK */
*hookptr = hook;
priv->lowerOrphan = orphan;
return (0);
}
/*
* Hooks are attached, adjust to force queueing.
* We don't really care which hook it is.
* they should all be queuing for outgoing data.
*/
static int
ng_gif_connect(hook_p hook)
{
NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
return (0);
}
/*
* Receive an incoming control message.
*/
static int
ng_gif_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mesg *resp = NULL;
int error = 0;
struct ng_mesg *msg;
NGI_GET_MSG(item, msg);
switch (msg->header.typecookie) {
case NGM_GIF_COOKIE:
switch (msg->header.cmd) {
case NGM_GIF_GET_IFNAME:
NG_MKRESPONSE(resp, msg, IFNAMSIZ, M_NOWAIT);
if (resp == NULL) {
error = ENOMEM;
break;
}
strlcpy(resp->data, priv->ifp->if_xname, IFNAMSIZ);
break;
case NGM_GIF_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;
default:
error = EINVAL;
break;
}
break;
default:
error = EINVAL;
break;
}
NG_RESPOND_MSG(error, node, item, resp);
NG_FREE_MSG(msg);
return (error);
}
/*
* Receive data on a hook.
*/
static int
ng_gif_rcvdata(hook_p hook, item_p item)
{
const node_p node = NG_HOOK_NODE(hook);
const priv_p priv = NG_NODE_PRIVATE(node);
struct mbuf *m;
NGI_GET_M(item, m);
NG_FREE_ITEM(item);
if (hook == priv->lower)
return ng_gif_rcv_lower(node, m);
panic("%s: weird hook", __func__);
}
/*
* Handle an mbuf received on the "lower" hook.
*/
static int
ng_gif_rcv_lower(node_p node, struct mbuf *m)
{
struct sockaddr dst;
const priv_p priv = NG_NODE_PRIVATE(node);
bzero(&dst, sizeof(dst));
/* Make sure header is fully pulled up */
if (m->m_pkthdr.len < sizeof(sa_family_t)) {
NG_FREE_M(m);
return (EINVAL);
}
if (m->m_len < sizeof(sa_family_t)
&& (m = m_pullup(m, sizeof(sa_family_t))) == NULL) {
return (ENOBUFS);
}
dst.sa_family = *mtod(m, sa_family_t *);
m_adj(m, sizeof(sa_family_t));
/* Send it on its way */
/*
* XXX: gif_output only uses dst for the family and passes the
* fourth argument (rt) to in{,6}_gif_output which ignore it.
* If this changes ng_gif will probably break.
*/
return gif_output(priv->ifp, m, &dst, NULL);
}
/*
* Shutdown node. This resets the node but does not remove it
* unless the REALLY_DIE flag is set.
*/
static int
ng_gif_shutdown(node_p node)
{
const priv_p priv = NG_NODE_PRIVATE(node);
if (node->nd_flags & NGF_REALLY_DIE) {
/*
* WE came here because the gif interface is being destroyed,
* so stop being persistant.
* Actually undo all the things we did on creation.
* Assume the ifp has already been freed.
*/
NG_NODE_SET_PRIVATE(node, NULL);
free(priv, M_NETGRAPH);
NG_NODE_UNREF(node); /* free node itself */
return (0);
}
NG_NODE_REVIVE(node); /* Signal ng_rmnode we are persisant */
return (0);
}
/*
* Hook disconnection.
*/
static int
ng_gif_disconnect(hook_p hook)
{
const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
if (hook == priv->lower) {
priv->lower = NULL;
priv->lowerOrphan = 0;
} else
panic("%s: weird hook", __func__);
if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
ng_rmnode_self(NG_HOOK_NODE(hook)); /* reset node */
return (0);
}
/******************************************************************
INITIALIZATION
******************************************************************/
/*
* Handle loading and unloading for this node type.
*/
static int
ng_gif_mod_event(module_t mod, int event, void *data)
{
VNET_ITERATOR_DECL(vnet_iter);
struct ifnet *ifp;
int error = 0;
int s;
s = splnet();
switch (event) {
case MOD_LOAD:
/* Register function hooks */
if (ng_gif_attach_p != NULL) {
error = EEXIST;
break;
}
ng_gif_attach_p = ng_gif_attach;
ng_gif_detach_p = ng_gif_detach;
ng_gif_input_p = ng_gif_input;
ng_gif_input_orphan_p = ng_gif_input_orphan;
/* Create nodes for any already-existing gif interfaces */
VNET_LIST_RLOCK();
IFNET_RLOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET_QUIET(vnet_iter); /* XXX revisit quiet */
TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
if (ifp->if_type == IFT_GIF)
ng_gif_attach(ifp);
}
CURVNET_RESTORE();
}
IFNET_RUNLOCK();
VNET_LIST_RUNLOCK();
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 gif interfaces are destroyed. 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.
*
* XXX: what about manual unloads?!?
*/
/* Unregister function hooks */
ng_gif_attach_p = NULL;
ng_gif_detach_p = NULL;
ng_gif_input_p = NULL;
ng_gif_input_orphan_p = NULL;
break;
default:
error = EOPNOTSUPP;
break;
}
splx(s);
return (error);
}