d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

netgraph/ng_bridge: move MACs via control message

Browse Source 
Use the new control message to move ethernet addresses from a link to
a new link in ng_bridge(4).  Send this message instead of doing the
work directly requires to move the loop detection into the control
message processing.  This will delay the loop detection by a few
frames.

This decouples the read-only activity from the modification under a
more strict writer lock.

Reviewed by:	manpages (gbe)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D28559
This commit is contained in:
Lutz Donnerhacke 2021-02-09 14:28:48 +01:00
parent 94eb6c42ab
commit f6e0c47169
2 changed files with 59 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
share/man/man4/ng_bridge.4
View File

@ -34,7 +34,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd February 17, 2021
.Dd May 13, 2021
.Dt NG_BRIDGE 4
.Os
.Sh NAME
@ -221,12 +221,19 @@ as an argument.
It assigns the MAC
.Va addr
to the
.Va hook ,
which must not be assigned yet.
.Va hook .
If the
.Va hook
is the empty string, the incoming hook of the control message is
used as fallback.
.Pp
If necessary, the MAC is removed from the currently assigned hook and
moved to the new one.
If the MAC is moved faster than
.Va minStableAge ,
the hook is considered as a loop and will block traffic for
.Va loopTimeout
seconds.
.Bd -literal -offset 0n
struct ng_bridge_move_host {
u_char addr[ETHER_ADDR_LEN]; /* ethernet address */

112
sys/netgraph/ng_bridge.c
View File

@ -103,7 +103,7 @@ struct ng_bridge_link_kernel_stats {
counter_u64_t xmitMulticasts; /* multicast pkts xmit'd on link */
counter_u64_t xmitBroadcasts; /* broadcast pkts xmit'd on link */
counter_u64_t loopDrops; /* pkts dropped due to loopback */
counter_u64_t loopDetects; /* number of loop detections */
u_int64_t loopDetects; /* number of loop detections */
counter_u64_t memoryFailures; /* times couldn't get mem or mbuf */
};
@ -420,7 +420,6 @@ ng_bridge_newhook(node_p node, hook_p hook, const char *name)
link->stats.xmitMulticasts = counter_u64_alloc(M_WAITOK);
link->stats.xmitBroadcasts = counter_u64_alloc(M_WAITOK);
link->stats.loopDrops = counter_u64_alloc(M_WAITOK);
link->stats.loopDetects = counter_u64_alloc(M_WAITOK);
link->stats.memoryFailures = counter_u64_alloc(M_WAITOK);
link->hook = hook;
@ -456,7 +455,7 @@ static void ng_bridge_clear_link_stats(struct ng_bridge_link_kernel_stats * p)
counter_u64_zero(p->xmitMulticasts);
counter_u64_zero(p->xmitBroadcasts);
counter_u64_zero(p->loopDrops);
counter_u64_zero(p->loopDetects);
p->loopDetects = 0;
counter_u64_zero(p->memoryFailures);
};
@ -573,7 +572,7 @@ ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
FETCH(xmitMulticasts);
FETCH(xmitBroadcasts);
FETCH(loopDrops);
FETCH(loopDetects);
rs->loopDetects = link->stats.loopDetects;
FETCH(memoryFailures);
#undef FETCH
}
@ -619,7 +618,6 @@ ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
struct ng_bridge_move_host *mh;
hook_p hook;
struct ng_bridge_host *host;
if (msg->header.arglen < sizeof(*mh)) {
error = EINVAL;
@ -633,11 +631,6 @@ ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
error = ENOENT;
break;
}
host = ng_bridge_get(priv, mh->addr);
if (host != NULL) {
error = EADDRINUSE;
break;
}
error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
break;
}
@ -784,7 +777,7 @@ ng_bridge_rcvdata(hook_p hook, item_p item)
counter_u64_add(ctx.incoming->stats.loopDrops, 1);
NG_FREE_ITEM(item);
NG_FREE_M(ctx.m);
return (ELOOP); /* XXX is this an appropriate error? */
return (ELOOP);
}
/* Update stats */
@ -799,56 +792,15 @@ ng_bridge_rcvdata(hook_p hook, item_p item)
}
/* Look up packet's source Ethernet address in hashtable */
if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
/* Update time since last heard from this host.
* This is safe without locking, because it's
* the only operation during shared access.
*/
host->staleness = 0;
/* Did host jump to a different link? */
if (host->link != ctx.incoming) {
/*
* 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 = ctx.m->m_pkthdr.rcvif;
char suffix[32];
if (ifp != NULL)
snprintf(suffix, sizeof(suffix),
" (%s)", ifp->if_xname);
else
*suffix = '\0';
log(LOG_WARNING, "ng_bridge: %s:"
" loopback detected on %s%s\n",
ng_bridge_nodename(node),
NG_HOOK_NAME(hook), suffix);
}
/* Mark link as linka non grata */
ctx.incoming->loopCount = priv->conf.loopTimeout;
counter_u64_add(ctx.incoming->stats.loopDetects, 1);
/* Forget all hosts on this link */
ng_bridge_remove_hosts(priv, ctx.incoming);
/* Drop packet */
counter_u64_add(ctx.incoming->stats.loopDrops, 1);
NG_FREE_ITEM(item);
NG_FREE_M(ctx.m);
return (ELOOP); /* XXX appropriate? */
}
/* Move host over to new link */
host->link = ctx.incoming;
host->age = 0;
}
} else if (ctx.incoming->learnMac) {
if ((host == NULL && ctx.incoming->learnMac) ||
(host != NULL && host->link != ctx.incoming)) {
struct ng_mesg *msg;
struct ng_bridge_move_host *mh;
int error = 0;
@ -871,6 +823,16 @@ ng_bridge_rcvdata(hook_p hook, item_p item)
counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
}
if (host != NULL && host->link != ctx.incoming) {
if (host->age < priv->conf.minStableAge) {
/* Drop packet on instable links */
counter_u64_add(ctx.incoming->stats.loopDrops, 1);
NG_FREE_ITEM(item);
NG_FREE_M(ctx.m);
return (ELOOP);
}
}
/* Run packet through ipfw processing, if enabled */
#if 0
if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
@ -970,7 +932,6 @@ ng_bridge_disconnect(hook_p hook)
counter_u64_free(link->stats.xmitMulticasts);
counter_u64_free(link->stats.xmitBroadcasts);
counter_u64_free(link->stats.loopDrops);
counter_u64_free(link->stats.loopDetects);
counter_u64_free(link->stats.memoryFailures);
free(link, M_NETGRAPH_BRIDGE);
priv->numLinks--;
@ -1012,8 +973,8 @@ ng_bridge_get(priv_cp priv, const u_char *addr)
}
/*
* Add a new host entry to the table. This assumes the host doesn't
* already exist in the table. Returns 0 on success.
* Add a host entry to the table. If it already exists, move it
* to the new link. Returns 0 on success.
*/
static int
ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
@ -1021,11 +982,36 @@ ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
const int bucket = HASH(addr, priv->hashMask);
struct ng_bridge_host *host;
#ifdef INVARIANTS
/* Assert that entry does not already exist in hashtable */
KASSERT(ng_bridge_get(priv, addr) == NULL,
("%s: entry %6D exists in table", __func__, addr, ":"));
#endif
if ((host = ng_bridge_get(priv, addr)) != NULL) {
/* Host already on the correct link? */
if (host->link == link)
return 0;
/* Move old host over to new link */
if (host->age >= priv->conf.minStableAge) {
host->link = link;
host->age = 0;
return (0);
}
/*
* If the host was recently moved to the old link and
* it's now jumping to a new link, declare a loopback
* condition.
*/
if (priv->conf.debugLevel >= 2)
log(LOG_WARNING, "ng_bridge: %s:"
" loopback detected on %s\n",
ng_bridge_nodename(priv->node),
NG_HOOK_NAME(link->hook));
/* 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, link);
return (ELOOP);
}
/* Allocate and initialize new hashtable entry */
host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);