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freebsd-nq/sys/netgraph/ng_bridge.c
Archie Cobbs a89effcde1 Fix typo in NETGRAPH_INIT() macro.
2000-10-09 18:37:11 +00:00

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/*
* ng_bridge.c
*
* Copyright (c) 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.
*
* Author: Archie Cobbs <archie@freebsd.org>
*
* $FreeBSD$
*/
/*
* ng_bridge(4) netgraph node type
*
* The node performs standard intelligent Ethernet bridging over
* each of its connected hooks, or links. A simple loop detection
* algorithm is included which disables a link for priv->conf.loopTimeout
* seconds when a host is seen to have jumped from one link to
* another within priv->conf.minStableAge seconds.
*
* We keep a hashtable that maps Ethernet addresses to host info,
* which is contained in struct ng_bridge_host's. These structures
* tell us on which link the host may be found. A host's entry will
* expire after priv->conf.maxStaleness seconds.
*
* This node is optimzed for stable networks, where machines jump
* from one port to the other only rarely.
*/
#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/ctype.h>
#include <net/if.h>
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/ip_fw.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_bridge.h>
#include <netgraph/ng_ether.h>
/* Per-link private data */
struct ng_bridge_link {
hook_p hook; /* netgraph hook */
u_int16_t loopCount; /* loop ignore timer */
struct ng_bridge_link_stats stats; /* link stats */
};
/* Per-node private data */
struct ng_bridge_private {
struct ng_bridge_bucket *tab; /* hash table bucket array */
struct ng_bridge_link *links[NG_BRIDGE_MAX_LINKS];
struct ng_bridge_config conf; /* node configuration */
node_p node; /* netgraph node */
u_int numHosts; /* num entries in table */
u_int numBuckets; /* num buckets in table */
u_int hashMask; /* numBuckets - 1 */
int numLinks; /* num connected links */
struct callout timer; /* one second periodic timer */
};
typedef struct ng_bridge_private *priv_p;
/* Information about a host, stored in a hash table entry */
struct ng_bridge_hent {
struct ng_bridge_host host; /* actual host info */
SLIST_ENTRY(ng_bridge_hent) next; /* next entry in bucket */
};
/* Hash table bucket declaration */
SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
/* Netgraph node methods */
static ng_constructor_t ng_bridge_constructor;
static ng_rcvmsg_t ng_bridge_rcvmsg;
static ng_shutdown_t ng_bridge_rmnode;
static ng_newhook_t ng_bridge_newhook;
static ng_rcvdata_t ng_bridge_rcvdata;
static ng_disconnect_t ng_bridge_disconnect;
/* Other internal functions */
static struct ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
static int ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
static void ng_bridge_rehash(priv_p priv);
static void ng_bridge_remove_hosts(priv_p priv, int linkNum);
static void ng_bridge_timeout(void *arg);
static const char *ng_bridge_nodename(node_p node);
/* Ethernet broadcast */
static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
/* Store each hook's link number in the private field */
#define LINK_NUM(hook) (*(u_int16_t *)(&(hook)->private))
/* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
#define ETHER_EQUAL(a,b) (((const u_int32_t *)(a))[0] \
== ((const u_int32_t *)(b))[0] \
&& ((const u_int16_t *)(a))[2] \
== ((const u_int16_t *)(b))[2])
/* Minimum and maximum number of hash buckets. Must be a power of two. */
#define MIN_BUCKETS (1 << 5) /* 32 */
#define MAX_BUCKETS (1 << 14) /* 16384 */
/* Configuration default values */
#define DEFAULT_LOOP_TIMEOUT 60
#define DEFAULT_MAX_STALENESS (15 * 60) /* same as ARP timeout */
#define DEFAULT_MIN_STABLE_AGE 1
/******************************************************************
NETGRAPH PARSE TYPES
******************************************************************/
/*
* How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
*/
static int
ng_bridge_getTableLength(const struct ng_parse_type *type,
const u_char *start, const u_char *buf)
{
const struct ng_bridge_host_ary *const hary
= (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
return hary->numHosts;
}
/* Parse type for struct ng_bridge_host_ary */
static const struct ng_parse_struct_info ng_bridge_host_type_info
= NG_BRIDGE_HOST_TYPE_INFO(&ng_ether_enaddr_type);
static const struct ng_parse_type ng_bridge_host_type = {
&ng_parse_struct_type,
&ng_bridge_host_type_info
};
static const struct ng_parse_array_info ng_bridge_hary_type_info = {
&ng_bridge_host_type,
ng_bridge_getTableLength
};
static const struct ng_parse_type ng_bridge_hary_type = {
&ng_parse_array_type,
&ng_bridge_hary_type_info
};
static const struct ng_parse_struct_info ng_bridge_host_ary_type_info
= NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
static const struct ng_parse_type ng_bridge_host_ary_type = {
&ng_parse_struct_type,
&ng_bridge_host_ary_type_info
};
/* Parse type for struct ng_bridge_config */
static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
&ng_parse_uint8_type,
NG_BRIDGE_MAX_LINKS
};
static const struct ng_parse_type ng_bridge_ipfwary_type = {
&ng_parse_fixedarray_type,
&ng_bridge_ipfwary_type_info
};
static const struct ng_parse_struct_info ng_bridge_config_type_info
= NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
static const struct ng_parse_type ng_bridge_config_type = {
&ng_parse_struct_type,
&ng_bridge_config_type_info
};
/* Parse type for struct ng_bridge_link_stat */
static const struct ng_parse_struct_info
ng_bridge_stats_type_info = NG_BRIDGE_STATS_TYPE_INFO;
static const struct ng_parse_type ng_bridge_stats_type = {
&ng_parse_struct_type,
&ng_bridge_stats_type_info
};
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_bridge_cmdlist[] = {
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_SET_CONFIG,
"setconfig",
&ng_bridge_config_type,
NULL
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_GET_CONFIG,
"getconfig",
NULL,
&ng_bridge_config_type
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_RESET,
"reset",
NULL,
NULL
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_GET_STATS,
"getstats",
&ng_parse_uint32_type,
&ng_bridge_stats_type
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_CLR_STATS,
"clrstats",
&ng_parse_uint32_type,
NULL
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_GETCLR_STATS,
"getclrstats",
&ng_parse_uint32_type,
&ng_bridge_stats_type
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_GET_TABLE,
"gettable",
NULL,
&ng_bridge_host_ary_type
},
{ 0 }
};
/* Node type descriptor */
static struct ng_type ng_bridge_typestruct = {
NG_VERSION,
NG_BRIDGE_NODE_TYPE,
NULL,
ng_bridge_constructor,
ng_bridge_rcvmsg,
ng_bridge_rmnode,
ng_bridge_newhook,
NULL,
NULL,
ng_bridge_rcvdata,
ng_bridge_rcvdata,
ng_bridge_disconnect,
ng_bridge_cmdlist,
};
NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
/* Depend on ng_ether so we can use the Ethernet parse type */
MODULE_DEPEND(ng_bridge, ng_ether, 1, 1, 1);
/******************************************************************
NETGRAPH NODE METHODS
******************************************************************/
/*
* Node constructor
*/
static int
ng_bridge_constructor(node_p *nodep)
{
priv_p priv;
int error;
/* Allocate and initialize private info */
MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT);
if (priv == NULL)
return (ENOMEM);
bzero(priv, sizeof(*priv));
callout_init(&priv->timer);
/* Allocate and initialize hash table, etc. */
MALLOC(priv->tab, struct ng_bridge_bucket *,
MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH, M_NOWAIT);
if (priv->tab == NULL) {
FREE(priv, M_NETGRAPH);
return (ENOMEM);
}
bzero(priv->tab, MIN_BUCKETS * sizeof(*priv->tab)); /* init SLIST's */
priv->numBuckets = MIN_BUCKETS;
priv->hashMask = MIN_BUCKETS - 1;
priv->conf.debugLevel = 1;
priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
/* Call superclass constructor */
if ((error = ng_make_node_common(&ng_bridge_typestruct, nodep))) {
FREE(priv, M_NETGRAPH);
return (error);
}
(*nodep)->private = priv;
priv->node = *nodep;
/* Start timer by faking a timeout event */
(*nodep)->refs++;
ng_bridge_timeout(*nodep);
return (0);
}
/*
* Method for attaching a new hook
*/
static int
ng_bridge_newhook(node_p node, hook_p hook, const char *name)
{
const priv_p priv = node->private;
/* Check for a link hook */
if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
const char *cp;
char *eptr;
u_long linkNum;
cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
return (EINVAL);
linkNum = strtoul(cp, &eptr, 10);
if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
return (EINVAL);
if (priv->links[linkNum] != NULL)
return (EISCONN);
MALLOC(priv->links[linkNum], struct ng_bridge_link *,
sizeof(*priv->links[linkNum]), M_NETGRAPH, M_NOWAIT);
if (priv->links[linkNum] == NULL)
return (ENOMEM);
bzero(priv->links[linkNum], sizeof(*priv->links[linkNum]));
priv->links[linkNum]->hook = hook;
LINK_NUM(hook) = linkNum;
priv->numLinks++;
return (0);
}
/* Unknown hook name */
return (EINVAL);
}
/*
* Receive a control message
*/
static int
ng_bridge_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
struct ng_mesg **rptr, hook_p lasthook)
{
const priv_p priv = node->private;
struct ng_mesg *resp = NULL;
int error = 0;
switch (msg->header.typecookie) {
case NGM_BRIDGE_COOKIE:
switch (msg->header.cmd) {
case NGM_BRIDGE_GET_CONFIG:
{
struct ng_bridge_config *conf;
NG_MKRESPONSE(resp, msg,
sizeof(struct ng_bridge_config), M_NOWAIT);
if (resp == NULL) {
error = ENOMEM;
break;
}
conf = (struct ng_bridge_config *)resp->data;
*conf = priv->conf; /* no sanity checking needed */
break;
}
case NGM_BRIDGE_SET_CONFIG:
{
struct ng_bridge_config *conf;
int i;
if (msg->header.arglen
!= sizeof(struct ng_bridge_config)) {
error = EINVAL;
break;
}
conf = (struct ng_bridge_config *)msg->data;
priv->conf = *conf;
for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
break;
}
case NGM_BRIDGE_RESET:
{
int i;
/* Flush all entries in the hash table */
ng_bridge_remove_hosts(priv, -1);
/* Reset all loop detection counters and stats */
for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
if (priv->links[i] == NULL)
continue;
priv->links[i]->loopCount = 0;
bzero(&priv->links[i]->stats,
sizeof(priv->links[i]->stats));
}
break;
}
case NGM_BRIDGE_GET_STATS:
case NGM_BRIDGE_CLR_STATS:
case NGM_BRIDGE_GETCLR_STATS:
{
struct ng_bridge_link *link;
int linkNum;
/* Get link number */
if (msg->header.arglen != sizeof(u_int32_t)) {
error = EINVAL;
break;
}
linkNum = *((u_int32_t *)msg->data);
if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
error = EINVAL;
break;
}
if ((link = priv->links[linkNum]) == NULL) {
error = ENOTCONN;
break;
}
/* Get/clear stats */
if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
NG_MKRESPONSE(resp, msg,
sizeof(link->stats), M_NOWAIT);
if (resp == NULL) {
error = ENOMEM;
break;
}
bcopy(&link->stats,
resp->data, sizeof(link->stats));
}
if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
bzero(&link->stats, sizeof(link->stats));
break;
}
case NGM_BRIDGE_GET_TABLE:
{
struct ng_bridge_host_ary *ary;
struct ng_bridge_hent *hent;
int i = 0, bucket;
NG_MKRESPONSE(resp, msg, sizeof(*ary)
+ (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
if (resp == NULL) {
error = ENOMEM;
break;
}
ary = (struct ng_bridge_host_ary *)resp->data;
ary->numHosts = priv->numHosts;
for (bucket = 0; bucket < priv->numBuckets; bucket++) {
SLIST_FOREACH(hent, &priv->tab[bucket], next)
ary->hosts[i++] = hent->host;
}
break;
}
default:
error = EINVAL;
break;
}
break;
default:
error = EINVAL;
break;
}
/* Done */
if (rptr)
*rptr = resp;
else if (resp != NULL)
FREE(resp, M_NETGRAPH);
FREE(msg, M_NETGRAPH);
return (error);
}
/*
* Receive data on a hook
*/
static int
ng_bridge_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
struct mbuf **ret_m, meta_p *ret_meta)
{
const node_p node = hook->node;
const priv_p priv = node->private;
struct ng_bridge_host *host;
struct ng_bridge_link *link;
struct ether_header *eh;
int error = 0, linkNum;
int i, manycast;
/* Get link number */
linkNum = LINK_NUM(hook);
KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
("%s: linkNum=%u", __FUNCTION__, linkNum));
link = priv->links[linkNum];
KASSERT(link != NULL, ("%s: link%d null", __FUNCTION__, linkNum));
/* Sanity check packet and pull up header */
if (m->m_pkthdr.len < ETHER_HDR_LEN) {
link->stats.recvRunts++;
NG_FREE_DATA(m, meta);
return (EINVAL);
}
if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
link->stats.memoryFailures++;
NG_FREE_META(meta);
return (ENOBUFS);
}
eh = mtod(m, struct ether_header *);
if ((eh->ether_shost[0] & 1) != 0) {
link->stats.recvInvalid++;
NG_FREE_DATA(m, meta);
return (EINVAL);
}
/* Is link disabled due to a loopback condition? */
if (link->loopCount != 0) {
link->stats.loopDrops++;
NG_FREE_DATA(m, meta);
return (ELOOP); /* XXX is this an appropriate error? */
}
/* Update stats */
link->stats.recvPackets++;
link->stats.recvOctets += m->m_pkthdr.len;
if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
link->stats.recvBroadcasts++;
manycast = 2;
} else
link->stats.recvMulticasts++;
}
/* Look up packet's source Ethernet address in hashtable */
if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
/* Update time since last heard from this host */
host->staleness = 0;
/* Did host jump to a different link? */
if (host->linkNum != linkNum) {
/*
* If the host's old link was recently established
* on the old link and it's already jumped to a new
* link, declare a loopback condition.
*/
if (host->age < priv->conf.minStableAge) {
/* Log the problem */
if (priv->conf.debugLevel >= 2) {
struct ifnet *ifp = m->m_pkthdr.rcvif;
char suffix[32];
if (ifp != NULL)
snprintf(suffix, sizeof(suffix),
" (%s%d)", ifp->if_name,
ifp->if_unit);
else
*suffix = '\0';
log(LOG_WARNING, "ng_bridge: %s:"
" loopback detected on %s%s\n",
ng_bridge_nodename(node),
hook->name, suffix);
}
/* Mark link as linka non grata */
link->loopCount = priv->conf.loopTimeout;
link->stats.loopDetects++;
/* Forget all hosts on this link */
ng_bridge_remove_hosts(priv, linkNum);
/* Drop packet */
link->stats.loopDrops++;
NG_FREE_DATA(m, meta);
return (ELOOP); /* XXX appropriate? */
}
/* Move host over to new link */
host->linkNum = linkNum;
host->age = 0;
}
} else {
if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
link->stats.memoryFailures++;
NG_FREE_DATA(m, meta);
return (ENOMEM);
}
}
/* Run packet through ipfw processing, if enabled */
if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
/* XXX not implemented yet */
}
/*
* If unicast and destination host known, deliver to host's link,
* unless it is the same link as the packet came in on.
*/
if (!manycast) {
/* Determine packet destination link */
if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
struct ng_bridge_link *const destLink
= priv->links[host->linkNum];
/* If destination same as incoming link, do nothing */
KASSERT(destLink != NULL,
("%s: link%d null", __FUNCTION__, host->linkNum));
if (destLink == link) {
NG_FREE_DATA(m, meta);
return (0);
}
/* Deliver packet out the destination link */
destLink->stats.xmitPackets++;
destLink->stats.xmitOctets += m->m_pkthdr.len;
NG_SEND_DATA(error, destLink->hook, m, meta);
return (error);
}
/* Destination host is not known */
link->stats.recvUnknown++;
}
/* Distribute unknown, multicast, broadcast pkts to all other links */
for (linkNum = i = 0; i < priv->numLinks - 1; linkNum++) {
struct ng_bridge_link *const destLink = priv->links[linkNum];
meta_p meta2 = NULL;
struct mbuf *m2;
/* Skip incoming link and disconnected links */
if (destLink == NULL || destLink == link)
continue;
/* Copy mbuf and meta info */
if (++i == priv->numLinks - 1) { /* last link */
m2 = m;
meta2 = meta;
} else {
m2 = m_dup(m, M_NOWAIT); /* XXX m_copypacket() */
if (m2 == NULL) {
link->stats.memoryFailures++;
NG_FREE_DATA(m, meta);
return (ENOBUFS);
}
if (meta != NULL
&& (meta2 = ng_copy_meta(meta)) == NULL) {
link->stats.memoryFailures++;
m_freem(m2);
NG_FREE_DATA(m, meta);
return (ENOMEM);
}
}
/* Update stats */
destLink->stats.xmitPackets++;
destLink->stats.xmitOctets += m->m_pkthdr.len;
switch (manycast) {
case 0: /* unicast */
break;
case 1: /* multicast */
destLink->stats.xmitMulticasts++;
break;
case 2: /* broadcast */
destLink->stats.xmitBroadcasts++;
break;
}
/* Send packet */
NG_SEND_DATA(error, destLink->hook, m2, meta2);
}
return (error);
}
/*
* Shutdown node
*/
static int
ng_bridge_rmnode(node_p node)
{
const priv_p priv = node->private;
ng_unname(node);
ng_cutlinks(node); /* frees all link and host info */
KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
("%s: numLinks=%d numHosts=%d",
__FUNCTION__, priv->numLinks, priv->numHosts));
FREE(priv->tab, M_NETGRAPH);
FREE(priv, M_NETGRAPH);
node->private = NULL;
ng_unref(node);
return (0);
}
/*
* Hook disconnection.
*/
static int
ng_bridge_disconnect(hook_p hook)
{
const priv_p priv = hook->node->private;
int linkNum;
/* Get link number */
linkNum = LINK_NUM(hook);
KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
("%s: linkNum=%u", __FUNCTION__, linkNum));
/* Remove all hosts associated with this link */
ng_bridge_remove_hosts(priv, linkNum);
/* Free associated link information */
KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __FUNCTION__));
FREE(priv->links[linkNum], M_NETGRAPH);
priv->links[linkNum] = NULL;
priv->numLinks--;
/* If no more hooks, go away */
if (hook->node->numhooks == 0)
ng_rmnode(hook->node);
return (0);
}
/******************************************************************
HASH TABLE FUNCTIONS
******************************************************************/
/*
* Hash algorithm
*
* Only hashing bytes 3-6 of the Ethernet address is sufficient and fast.
*/
#define HASH(addr,mask) ( (((const u_int16_t *)(addr))[0] \
^ ((const u_int16_t *)(addr))[1] \
^ ((const u_int16_t *)(addr))[2]) & (mask) )
/*
* Find a host entry in the table.
*/
static struct ng_bridge_host *
ng_bridge_get(priv_p priv, const u_char *addr)
{
const int bucket = HASH(addr, priv->hashMask);
struct ng_bridge_hent *hent;
SLIST_FOREACH(hent, &priv->tab[bucket], next) {
if (ETHER_EQUAL(hent->host.addr, addr))
return (&hent->host);
}
return (NULL);
}
/*
* Add a new host entry to the table. This assumes the host doesn't
* already exist in the table. Returns 1 on success, 0 if there
* was a memory allocation failure.
*/
static int
ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
{
const int bucket = HASH(addr, priv->hashMask);
struct ng_bridge_hent *hent;
#ifdef INVARIANTS
/* Assert that entry does not already exist in hashtable */
SLIST_FOREACH(hent, &priv->tab[bucket], next) {
KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
("%s: entry %6D exists in table", __FUNCTION__, addr, ":"));
}
#endif
/* Allocate and initialize new hashtable entry */
MALLOC(hent, struct ng_bridge_hent *,
sizeof(*hent), M_NETGRAPH, M_NOWAIT);
if (hent == NULL)
return (0);
bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
hent->host.linkNum = linkNum;
hent->host.staleness = 0;
hent->host.age = 0;
/* Add new element to hash bucket */
SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
priv->numHosts++;
/* Resize table if necessary */
ng_bridge_rehash(priv);
return (1);
}
/*
* Resize the hash table. We try to maintain the number of buckets
* such that the load factor is in the range 0.25 to 1.0.
*
* If we can't get the new memory then we silently fail. This is OK
* because things will still work and we'll try again soon anyway.
*/
static void
ng_bridge_rehash(priv_p priv)
{
struct ng_bridge_bucket *newTab;
int oldBucket, newBucket;
int newNumBuckets;
u_int newMask;
/* Is table too full or too empty? */
if (priv->numHosts > priv->numBuckets
&& (priv->numBuckets << 1) <= MAX_BUCKETS)
newNumBuckets = priv->numBuckets << 1;
else if (priv->numHosts < (priv->numBuckets >> 2)
&& (priv->numBuckets >> 2) >= MIN_BUCKETS)
newNumBuckets = priv->numBuckets >> 2;
else
return;
newMask = newNumBuckets - 1;
/* Allocate and initialize new table */
MALLOC(newTab, struct ng_bridge_bucket *,
newNumBuckets * sizeof(*newTab), M_NETGRAPH, M_NOWAIT);
if (newTab == NULL)
return;
bzero(newTab, newNumBuckets * sizeof(*newTab));
/* Move all entries from old table to new table */
for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
while (!SLIST_EMPTY(oldList)) {
struct ng_bridge_hent *const hent
= SLIST_FIRST(oldList);
SLIST_REMOVE_HEAD(oldList, next);
newBucket = HASH(hent->host.addr, newMask);
SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
}
}
/* Replace old table with new one */
if (priv->conf.debugLevel >= 3) {
log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
ng_bridge_nodename(priv->node),
priv->numBuckets, newNumBuckets);
}
FREE(priv->tab, M_NETGRAPH);
priv->numBuckets = newNumBuckets;
priv->hashMask = newMask;
priv->tab = newTab;
return;
}
/******************************************************************
MISC FUNCTIONS
******************************************************************/
/*
* Remove all hosts associated with a specific link from the hashtable.
* If linkNum == -1, then remove all hosts in the table.
*/
static void
ng_bridge_remove_hosts(priv_p priv, int linkNum)
{
int bucket;
for (bucket = 0; bucket < priv->numBuckets; bucket++) {
struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
while (*hptr != NULL) {
struct ng_bridge_hent *const hent = *hptr;
if (linkNum == -1 || hent->host.linkNum == linkNum) {
*hptr = SLIST_NEXT(hent, next);
FREE(hent, M_NETGRAPH);
priv->numHosts--;
} else
hptr = &SLIST_NEXT(hent, next);
}
}
}
/*
* Handle our once-per-second timeout event. We do two things:
* we decrement link->loopCount for those links being muted due to
* a detected loopback condition, and we remove any hosts from
* the hashtable whom we haven't heard from in a long while.
*/
static void
ng_bridge_timeout(void *arg)
{
const node_p node = arg;
const priv_p priv = node->private;
int s, bucket;
int counter = 0;
int linkNum;
/* Avoid race condition with ng_bridge_shutdown() */
s = splnet();
if ((node->flags & NG_INVALID) != 0 || priv == NULL) {
ng_unref(node);
splx(s);
return;
}
/* Register a new timeout, keeping the existing node reference */
callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
/* Update host time counters and remove stale entries */
for (bucket = 0; bucket < priv->numBuckets; bucket++) {
struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
while (*hptr != NULL) {
struct ng_bridge_hent *const hent = *hptr;
/* Make sure host's link really exists */
KASSERT(priv->links[hent->host.linkNum] != NULL,
("%s: host %6D on nonexistent link %d\n",
__FUNCTION__, hent->host.addr, ":",
hent->host.linkNum));
/* Remove hosts we haven't heard from in a while */
if (++hent->host.staleness >= priv->conf.maxStaleness) {
*hptr = SLIST_NEXT(hent, next);
FREE(hent, M_NETGRAPH);
priv->numHosts--;
} else {
if (hent->host.age < 0xffff)
hent->host.age++;
hptr = &SLIST_NEXT(hent, next);
counter++;
}
}
}
KASSERT(priv->numHosts == counter,
("%s: hosts: %d != %d", __FUNCTION__, priv->numHosts, counter));
/* Decrease table size if necessary */
ng_bridge_rehash(priv);
/* Decrease loop counter on muted looped back links */
for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
struct ng_bridge_link *const link = priv->links[linkNum];
if (link != NULL) {
if (link->loopCount != 0) {
link->loopCount--;
if (link->loopCount == 0
&& priv->conf.debugLevel >= 2) {
log(LOG_INFO, "ng_bridge: %s:"
" restoring looped back link%d\n",
ng_bridge_nodename(node), linkNum);
}
}
counter++;
}
}
KASSERT(priv->numLinks == counter,
("%s: links: %d != %d", __FUNCTION__, priv->numLinks, counter));
/* Done */
splx(s);
}
/*
* Return node's "name", even if it doesn't have one.
*/
static const char *
ng_bridge_nodename(node_p node)
{
static char name[NG_NODELEN+1];
if (node->name != NULL)
snprintf(name, sizeof(name), "%s", node->name);
else
snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
return name;
}
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