git: 6d7b0f3fe9b5 - stable/12 - netgraph/ng_bridge: move MACs via control message
Lutz Donnerhacke
donner at FreeBSD.org
Thu May 27 11:07:48 UTC 2021
The branch stable/12 has been updated by donner:
URL: https://cgit.FreeBSD.org/src/commit/?id=6d7b0f3fe9b5cd41fa8404a70d34701400487e2b
commit 6d7b0f3fe9b5cd41fa8404a70d34701400487e2b
Author: Lutz Donnerhacke <donner at FreeBSD.org>
AuthorDate: 2021-02-09 13:28:48 +0000
Commit: Lutz Donnerhacke <donner at FreeBSD.org>
CommitDate: 2021-05-27 11:04:39 +0000
netgraph/ng_bridge: move MACs via control message
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)
Differential Revision: https://reviews.freebsd.org/D28559
(cherry picked from commit f6e0c471691e0005e450ec968a9fa3b5346a3c45)
---
share/man/man4/ng_bridge.4 | 13 ++++--
sys/netgraph/ng_bridge.c | 114 +++++++++++++++++++--------------------------
2 files changed, 59 insertions(+), 68 deletions(-)
diff --git a/share/man/man4/ng_bridge.4 b/share/man/man4/ng_bridge.4
index e3f406c3f437..0387157f0622 100644
--- a/share/man/man4/ng_bridge.4
+++ b/share/man/man4/ng_bridge.4
@@ -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 */
diff --git a/sys/netgraph/ng_bridge.c b/sys/netgraph/ng_bridge.c
index 0d5e2ffb196d..17e840a06289 100644
--- a/sys/netgraph/ng_bridge.c
+++ b/sys/netgraph/ng_bridge.c
@@ -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);
};
@@ -641,7 +640,7 @@ 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
}
@@ -687,7 +686,6 @@ 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;
@@ -701,11 +699,6 @@ 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;
}
@@ -858,7 +851,7 @@ 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 */
@@ -873,58 +866,15 @@ 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;
@@ -947,6 +897,16 @@ 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) {
@@ -1046,7 +1006,6 @@ 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--;
@@ -1088,8 +1047,8 @@ 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)
@@ -1097,11 +1056,36 @@ 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);
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