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netgraph/ng_bridge: learn MACs via control message

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Add a new control message to move ethernet addresses to a given link
in ng_bridge(4). Send this message instead of doing the work directly.
This decouples the read-only activity from the modification under a
more strict writer lock.

Decoupling the work is a prerequisite for multithreaded operation.

Approved by:	manpages (bcr), kp (earlier version)
Differential Revision:	https://reviews.freebsd.org/D28516

(cherry picked from commit b1bd44732d)
This commit is contained in:
Lutz Donnerhacke 2021-05-04 22:14:59 +02:00
parent ff4447ac31
commit 53ccd92495
3 changed files with 91 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
share/man/man4/ng_bridge.4
View File

@ -34,7 +34,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd February 6, 2021
.Dd February 17, 2021
.Dt NG_BRIDGE 4
.Os
.Sh NAME
@ -214,6 +214,25 @@ Returns the current host mapping table used to direct packets, in a
.Vt "struct ng_bridge_host_ary" .
.It Dv NGM_BRIDGE_SET_PERSISTENT Pq Ar setpersistent
This command sets the persistent flag on the node, and takes no arguments.
.It Dv NGM_BRIDGE_MOVE_HOST Pq Ar movehost
This command takes a
.Vt "struct ng_bridge_move_host"
as an argument.
It assigns the MAC
.Va addr
to the
.Va hook ,
which must not be assigned yet.
If the
.Va hook
is the empty string, the incoming hook of the control message is
used as fallback.
.Bd -literal -offset 0n
struct ng_bridge_move_host {
u_char addr[ETHER_ADDR_LEN]; /* ethernet address */
char hook[NG_HOOKSIZ]; /* link where addr can be found */
};
.Ed
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a

67
sys/netgraph/ng_bridge.c
View File

@ -234,6 +234,13 @@ static const struct ng_parse_type ng_bridge_stats_type = {
&ng_parse_struct_type,
&ng_bridge_stats_type_fields
};
/* Parse type for struct ng_bridge_move_host */
static const struct ng_parse_struct_field ng_bridge_move_host_type_fields[]
= NG_BRIDGE_MOVE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
static const struct ng_parse_type ng_bridge_move_host_type = {
&ng_parse_struct_type,
&ng_bridge_move_host_type_fields
};
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_bridge_cmdlist[] = {
@ -293,6 +300,13 @@ static const struct ng_cmdlist ng_bridge_cmdlist[] = {
NULL,
NULL
},
{
NGM_BRIDGE_COOKIE,
NGM_BRIDGE_MOVE_HOST,
"movehost",
&ng_bridge_move_host_type,
NULL
},
{ 0 }
};
@ -670,6 +684,32 @@ ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
priv->persistent = 1;
break;
}
case NGM_BRIDGE_MOVE_HOST:
{
struct ng_bridge_move_host *mh;
hook_p hook;
struct ng_bridge_host *host;
if (msg->header.arglen < sizeof(*mh)) {
error = EINVAL;
break;
}
mh = (struct ng_bridge_move_host *)msg->data;
hook = (mh->hook[0] == 0)
? lasthook
: ng_findhook(node, mh->hook);
if (hook == NULL) {
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;
}
default:
error = EINVAL;
break;
@ -884,12 +924,26 @@ ng_bridge_rcvdata(hook_p hook, item_p item)
host->age = 0;
}
} else if (ctx.incoming->learnMac) {
if (!ng_bridge_put(priv, eh->ether_shost, ctx.incoming)) {
struct ng_mesg *msg;
struct ng_bridge_move_host *mh;
int error = 0;
NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
sizeof(*mh), M_NOWAIT);
if (msg == NULL) {
counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
NG_FREE_ITEM(item);
NG_FREE_M(ctx.m);
return (ENOMEM);
}
mh = (struct ng_bridge_move_host *)msg->data;
strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
sizeof(mh->hook));
memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
NG_NODE_ID(node));
if (error)
counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
}
/* Run packet through ipfw processing, if enabled */
@ -1033,8 +1087,7 @@ 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 1 on success, 0 if there
* was a memory allocation failure.
* already exist in the table. Returns 0 on success.
*/
static int
ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
@ -1044,16 +1097,14 @@ ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
#ifdef INVARIANTS
/* Assert that entry does not already exist in hashtable */
SLIST_FOREACH(host, &priv->tab[bucket], next) {
KASSERT(!ETHER_EQUAL(host->addr, addr),
KASSERT(ng_bridge_get(priv, addr) == NULL,
("%s: entry %6D exists in table", __func__, addr, ":"));
}
#endif
/* Allocate and initialize new hashtable entry */
host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
if (host == NULL)
return (0);
return (ENOMEM);
bcopy(addr, host->addr, ETHER_ADDR_LEN);
host->link = link;
host->staleness = 0;
@ -1065,7 +1116,7 @@ ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
/* Resize table if necessary */
ng_bridge_rehash(priv);
return (1);
return (0);
}
/*

11
sys/netgraph/ng_bridge.h
View File

@ -183,6 +183,16 @@ struct ng_bridge_host_tbl_ary {
};
#endif /* NGM_BRIDGE_TABLE_ABI */
struct ng_bridge_move_host {
u_char addr[ETHER_ADDR_LEN]; /* ethernet address */
char hook[NG_HOOKSIZ]; /* link where addr can be found */
};
/* Keep this in sync with the above structure definition */
#define NG_BRIDGE_MOVE_HOST_TYPE_INFO(entype) { \
{ "addr", (entype) }, \
{ "hook", &ng_parse_hookbuf_type }, \
}
/* Netgraph control messages */
enum {
NGM_BRIDGE_SET_CONFIG = 1, /* set node configuration */
@ -193,6 +203,7 @@ enum {
NGM_BRIDGE_GETCLR_STATS, /* atomically get & clear link stats */
NGM_BRIDGE_GET_TABLE, /* get link table */
NGM_BRIDGE_SET_PERSISTENT, /* set persistent mode */
NGM_BRIDGE_MOVE_HOST, /* move a host to a link */
};
#endif /* _NETGRAPH_NG_BRIDGE_H_ */