tipc: make bearer packet filtering generic
In commit 5b7066c3dd24 ("tipc: stricter filtering of packets in bearer
layer") we introduced a method of filtering out messages while a bearer
is being reset, to avoid that links may be re-created and come back in
working state while we are still in the process of shutting them down.
This solution works well, but is limited to only work with L2 media, which
is insufficient with the increasing use of UDP as carrier media.
We now replace this solution with a more generic one, by introducing a
new flag "up" in the generic struct tipc_bearer. This field will be set
and reset at the same locations as with the previous solution, while
the packet filtering is moved to the generic code for the sending side.
On the receiving side, the filtering is still done in media specific
code, but now including the UDP bearer.
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 65b1bbf..6fc4e3c 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -56,6 +56,13 @@
NULL
};
+static struct tipc_bearer *bearer_get(struct net *net, int bearer_id)
+{
+ struct tipc_net *tn = tipc_net(net);
+
+ return rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
+}
+
static void bearer_disable(struct net *net, struct tipc_bearer *b);
/**
@@ -323,6 +330,7 @@
b->domain = disc_domain;
b->net_plane = bearer_id + 'A';
b->priority = priority;
+ test_and_set_bit_lock(0, &b->up);
res = tipc_disc_create(net, b, &b->bcast_addr, &skb);
if (res) {
@@ -360,15 +368,24 @@
*/
void tipc_bearer_reset_all(struct net *net)
{
- struct tipc_net *tn = tipc_net(net);
struct tipc_bearer *b;
int i;
for (i = 0; i < MAX_BEARERS; i++) {
- b = rcu_dereference_rtnl(tn->bearer_list[i]);
+ b = bearer_get(net, i);
+ if (b)
+ clear_bit_unlock(0, &b->up);
+ }
+ for (i = 0; i < MAX_BEARERS; i++) {
+ b = bearer_get(net, i);
if (b)
tipc_reset_bearer(net, b);
}
+ for (i = 0; i < MAX_BEARERS; i++) {
+ b = bearer_get(net, i);
+ if (b)
+ test_and_set_bit_lock(0, &b->up);
+ }
}
/**
@@ -382,8 +399,9 @@
int bearer_id = b->identity;
pr_info("Disabling bearer <%s>\n", b->name);
- b->media->disable_media(b);
+ clear_bit_unlock(0, &b->up);
tipc_node_delete_links(net, bearer_id);
+ b->media->disable_media(b);
RCU_INIT_POINTER(b->media_ptr, NULL);
if (b->link_req)
tipc_disc_delete(b->link_req);
@@ -440,22 +458,16 @@
{
struct net_device *dev;
int delta;
- void *tipc_ptr;
dev = (struct net_device *)rcu_dereference_rtnl(b->media_ptr);
if (!dev)
return 0;
- /* Send RESET message even if bearer is detached from device */
- tipc_ptr = rcu_dereference_rtnl(dev->tipc_ptr);
- if (unlikely(!tipc_ptr && !msg_is_reset(buf_msg(skb))))
- goto drop;
-
- delta = dev->hard_header_len - skb_headroom(skb);
- if ((delta > 0) &&
- pskb_expand_head(skb, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC))
- goto drop;
-
+ delta = SKB_DATA_ALIGN(dev->hard_header_len - skb_headroom(skb));
+ if ((delta > 0) && pskb_expand_head(skb, delta, 0, GFP_ATOMIC)) {
+ kfree_skb(skb);
+ return 0;
+ }
skb_reset_network_header(skb);
skb->dev = dev;
skb->protocol = htons(ETH_P_TIPC);
@@ -463,9 +475,6 @@
dev->dev_addr, skb->len);
dev_queue_xmit(skb);
return 0;
-drop:
- kfree_skb(skb);
- return 0;
}
int tipc_bearer_mtu(struct net *net, u32 bearer_id)
@@ -487,12 +496,12 @@
struct sk_buff *skb,
struct tipc_media_addr *dest)
{
- struct tipc_net *tn = tipc_net(net);
+ struct tipc_msg *hdr = buf_msg(skb);
struct tipc_bearer *b;
rcu_read_lock();
- b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
- if (likely(b))
+ b = bearer_get(net, bearer_id);
+ if (likely(b && (test_bit(0, &b->up) || msg_is_reset(hdr))))
b->media->send_msg(net, skb, b, dest);
else
kfree_skb(skb);
@@ -505,7 +514,6 @@
struct sk_buff_head *xmitq,
struct tipc_media_addr *dst)
{
- struct tipc_net *tn = net_generic(net, tipc_net_id);
struct tipc_bearer *b;
struct sk_buff *skb, *tmp;
@@ -513,12 +521,15 @@
return;
rcu_read_lock();
- b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
+ b = bearer_get(net, bearer_id);
if (unlikely(!b))
__skb_queue_purge(xmitq);
skb_queue_walk_safe(xmitq, skb, tmp) {
__skb_dequeue(xmitq);
- b->media->send_msg(net, skb, b, dst);
+ if (likely(test_bit(0, &b->up) || msg_is_reset(buf_msg(skb))))
+ b->media->send_msg(net, skb, b, dst);
+ else
+ kfree(skb);
}
rcu_read_unlock();
}
@@ -535,8 +546,8 @@
struct tipc_msg *hdr;
rcu_read_lock();
- b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);
- if (unlikely(!b))
+ b = bearer_get(net, bearer_id);
+ if (unlikely(!b || !test_bit(0, &b->up)))
__skb_queue_purge(xmitq);
skb_queue_walk_safe(xmitq, skb, tmp) {
hdr = buf_msg(skb);
@@ -566,7 +577,8 @@
rcu_read_lock();
b = rcu_dereference_rtnl(dev->tipc_ptr);
- if (likely(b && (skb->pkt_type <= PACKET_BROADCAST))) {
+ if (likely(b && test_bit(0, &b->up) &&
+ (skb->pkt_type <= PACKET_BROADCAST))) {
skb->next = NULL;
tipc_rcv(dev_net(dev), skb, b);
rcu_read_unlock();
@@ -591,18 +603,9 @@
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
- struct tipc_net *tn = tipc_net(net);
struct tipc_bearer *b;
- int i;
b = rtnl_dereference(dev->tipc_ptr);
- if (!b) {
- for (i = 0; i < MAX_BEARERS; b = NULL, i++) {
- b = rtnl_dereference(tn->bearer_list[i]);
- if (b && (b->media_ptr == dev))
- break;
- }
- }
if (!b)
return NOTIFY_DONE;
@@ -613,11 +616,10 @@
if (netif_carrier_ok(dev))
break;
case NETDEV_UP:
- rcu_assign_pointer(dev->tipc_ptr, b);
+ test_and_set_bit_lock(0, &b->up);
break;
case NETDEV_GOING_DOWN:
- RCU_INIT_POINTER(dev->tipc_ptr, NULL);
- synchronize_net();
+ clear_bit_unlock(0, &b->up);
tipc_reset_bearer(net, b);
break;
case NETDEV_CHANGEMTU:
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 43757f1..83a9abb 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -150,6 +150,7 @@
u32 identity;
struct tipc_link_req *link_req;
char net_plane;
+ unsigned long up;
};
struct tipc_bearer_names {
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index b016c01..33bdf54 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -224,7 +224,7 @@
rcu_read_lock();
b = rcu_dereference_rtnl(ub->bearer);
- if (b) {
+ if (b && test_bit(0, &b->up)) {
tipc_rcv(sock_net(sk), skb, b);
rcu_read_unlock();
return 0;