xen-netback: add support for multicast control

Xen's PV network protocol includes messages to add/remove ethernet multicast addresses to/from a filter list in the backend. This allows the frontend to request the backend only forward multicast packets which are of interest thus preventing unnecessary noise on the shared ring. The canonical netif header in git://xenbits.xen.org/xen.git specifies the message format (two more XEN_NETIF_EXTRA_TYPEs) so the minimal necessary changes have been pulled into include/xen/interface/io/netif.h. To prevent the frontend from extending the multicast filter list arbitrarily a limit (XEN_NETBK_MCAST_MAX) has been set to 64 entries. This limit is not specified by the protocol and so may change in future. If the limit is reached then the next XEN_NETIF_EXTRA_TYPE_MCAST_ADD sent by the frontend will be failed with NETIF_RSP_ERROR. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
author: Paul Durrant <Paul.Durrant@citrix.com> 2015-09-02 12:58:36 -0400
committer: David S. Miller <davem@davemloft.net> 2015-09-02 14:45:00 -0400
commit: 210c34dcd8d912dcc740f1f17625a7293af5cb56 (patch)
tree: 33b7944163879cad30a6e631490ad6d2d3297164 /drivers/net/xen-netback/netback.c
parent: 4db78d31deff77f227de56316ee865d65eaa7f01 (diff)
1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 3f44b522b831..42569b994ea8 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1157,6 +1157,80 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
        return false;
 }
+/* No locking is required in xenvif_mcast_add/del() as they are
+ * only ever invoked from NAPI poll. An RCU list is used because
+ * xenvif_mcast_match() is called asynchronously, during start_xmit.
+ */
+static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
+{
+        struct xenvif_mcast_addr *mcast;
+        if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
+                if (net_ratelimit())
+                        netdev_err(vif->dev,
+                                   "Too many multicast addresses\n");
+                return -ENOSPC;
+        }
+        mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
+        if (!mcast)
+                return -ENOMEM;
+        ether_addr_copy(mcast->addr, addr);
+        list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
+        vif->fe_mcast_count++;
+        return 0;
+}
+static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
+{
+        struct xenvif_mcast_addr *mcast;
+        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
+                if (ether_addr_equal(addr, mcast->addr)) {
+                        --vif->fe_mcast_count;
+                        list_del_rcu(&mcast->entry);
+                        kfree_rcu(mcast, rcu);
+                        break;
+                }
+        }
+}
+bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
+{
+        struct xenvif_mcast_addr *mcast;
+        rcu_read_lock();
+        list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
+                if (ether_addr_equal(addr, mcast->addr)) {
+                        rcu_read_unlock();
+                        return true;
+                }
+        }
+        rcu_read_unlock();
+        return false;
+}
+void xenvif_mcast_addr_list_free(struct xenvif *vif)
+{
+        /* No need for locking or RCU here. NAPI poll and TX queue
+         * are stopped.
+         */
+        while (!list_empty(&vif->fe_mcast_addr)) {
+                struct xenvif_mcast_addr *mcast;
+                mcast = list_first_entry(&vif->fe_mcast_addr,
+                                         struct xenvif_mcast_addr,
+                                         entry);
+                --vif->fe_mcast_count;
+                list_del(&mcast->entry);
+                kfree(mcast);
+        }
+}
 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
                                     int budget,
                                     unsigned *copy_ops,
@@ -1215,6 +1289,31 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
                                break;
                }
+                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
+                        struct xen_netif_extra_info *extra;
+                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
+                        ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
+                        make_tx_response(queue, &txreq,
+                                         (ret == 0) ?
+                                         XEN_NETIF_RSP_OKAY :
+                                         XEN_NETIF_RSP_ERROR);
+                        push_tx_responses(queue);
+                        continue;
+                }
+                if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
+                        struct xen_netif_extra_info *extra;
+                        extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
+                        xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
+                        make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
+                        push_tx_responses(queue);
+                        continue;
+                }
                ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
                if (unlikely(ret < 0))
                        break;
author	Paul Durrant <Paul.Durrant@citrix.com>	2015-09-02 12:58:36 -0400
committer	David S. Miller <davem@davemloft.net>	2015-09-02 14:45:00 -0400
commit	210c34dcd8d912dcc740f1f17625a7293af5cb56 (patch)
tree	33b7944163879cad30a6e631490ad6d2d3297164 /drivers/net/xen-netback/netback.c
parent	4db78d31deff77f227de56316ee865d65eaa7f01 (diff)

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 3f44b522b831..42569b994ea8 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c
@@ -1157,6 +1157,80 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1157	return false;	1157	return false;
1158	}	1158	}
1159		1159
		1160	/* No locking is required in xenvif_mcast_add/del() as they are
		1161	* only ever invoked from NAPI poll. An RCU list is used because
		1162	* xenvif_mcast_match() is called asynchronously, during start_xmit.
		1163	*/
		1164
		1165	static int xenvif_mcast_add(struct xenvif vif, const u8 addr)
		1166	{
		1167	struct xenvif_mcast_addr *mcast;
		1168
		1169	if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
		1170	if (net_ratelimit())
		1171	netdev_err(vif->dev,
		1172	"Too many multicast addresses\n");
		1173	return -ENOSPC;
		1174	}
		1175
		1176	mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
		1177	if (!mcast)
		1178	return -ENOMEM;
		1179
		1180	ether_addr_copy(mcast->addr, addr);
		1181	list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
		1182	vif->fe_mcast_count++;
		1183
		1184	return 0;
		1185	}
		1186
		1187	static void xenvif_mcast_del(struct xenvif vif, const u8 addr)
		1188	{
		1189	struct xenvif_mcast_addr *mcast;
		1190
		1191	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
		1192	if (ether_addr_equal(addr, mcast->addr)) {
		1193	--vif->fe_mcast_count;
		1194	list_del_rcu(&mcast->entry);
		1195	kfree_rcu(mcast, rcu);
		1196	break;
		1197	}
		1198	}
		1199	}
		1200
		1201	bool xenvif_mcast_match(struct xenvif vif, const u8 addr)
		1202	{
		1203	struct xenvif_mcast_addr *mcast;
		1204
		1205	rcu_read_lock();
		1206	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
		1207	if (ether_addr_equal(addr, mcast->addr)) {
		1208	rcu_read_unlock();
		1209	return true;
		1210	}
		1211	}
		1212	rcu_read_unlock();
		1213
		1214	return false;
		1215	}
		1216
		1217	void xenvif_mcast_addr_list_free(struct xenvif *vif)
		1218	{
		1219	/* No need for locking or RCU here. NAPI poll and TX queue
		1220	* are stopped.
		1221	*/
		1222	while (!list_empty(&vif->fe_mcast_addr)) {
		1223	struct xenvif_mcast_addr *mcast;
		1224
		1225	mcast = list_first_entry(&vif->fe_mcast_addr,
		1226	struct xenvif_mcast_addr,
		1227	entry);
		1228	--vif->fe_mcast_count;
		1229	list_del(&mcast->entry);
		1230	kfree(mcast);
		1231	}
		1232	}
		1233
1160	static void xenvif_tx_build_gops(struct xenvif_queue *queue,	1234	static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1161	int budget,	1235	int budget,
1162	unsigned *copy_ops,	1236	unsigned *copy_ops,
@@ -1215,6 +1289,31 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1215	break;	1289	break;
1216	}	1290	}
1217		1291
		1292	if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
		1293	struct xen_netif_extra_info *extra;
		1294
		1295	extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
		1296	ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
		1297
		1298	make_tx_response(queue, &txreq,
		1299	(ret == 0) ?
		1300	XEN_NETIF_RSP_OKAY :
		1301	XEN_NETIF_RSP_ERROR);
		1302	push_tx_responses(queue);
		1303	continue;
		1304	}
		1305
		1306	if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
		1307	struct xen_netif_extra_info *extra;
		1308
		1309	extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
		1310	xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
		1311
		1312	make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
		1313	push_tx_responses(queue);
		1314	continue;
		1315	}
		1316
1218	ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);	1317	ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1219	if (unlikely(ret < 0))	1318	if (unlikely(ret < 0))
1220	break;	1319	break;