[net-next] tipc: improve throughput between nodes in netns
diff mbox series

Message ID 20191022022036.19961-1-hoang.h.le@dektech.com.au
State Changes Requested
Delegated to: David Miller
Headers show
Series
  • [net-next] tipc: improve throughput between nodes in netns
Related show

Commit Message

Hoang Le Oct. 22, 2019, 2:20 a.m. UTC
Currently, TIPC transports intra-node user data messages directly
socket to socket, hence shortcutting all the lower layers of the
communication stack. This gives TIPC very good intra node performance,
both regarding throughput and latency.

We now introduce a similar mechanism for TIPC data traffic across
network namespaces located in the same kernel. On the send path, the
call chain is as always accompanied by the sending node's network name
space pointer. However, once we have reliably established that the
receiving node is represented by a namespace on the same host, we just
replace the namespace pointer with the receiving node/namespace's
ditto, and follow the regular socket receive patch though the receiving
node. This technique gives us a throughput similar to the node internal
throughput, several times larger than if we let the traffic go though
the full network stacks. As a comparison, max throughput for 64k
messages is four times larger than TCP throughput for the same type of
traffic.

To meet any security concerns, the following should be noted.

- All nodes joining a cluster are supposed to have been be certified
and authenticated by mechanisms outside TIPC. This is no different for
nodes/namespaces on the same host; they have to auto discover each
other using the attached interfaces, and establish links which are
supervised via the regular link monitoring mechanism. Hence, a kernel
local node has no other way to join a cluster than any other node, and
have to obey to policies set in the IP or device layers of the stack.

- Only when a sender has established with 100% certainty that the peer
node is located in a kernel local namespace does it choose to let user
data messages, and only those, take the crossover path to the receiving
node/namespace.

- If the receiving node/namespace is removed, its namespace pointer
is invalidated at all peer nodes, and their neighbor link monitoring
will eventually note that this node is gone.

- To ensure the "100% certainty" criteria, and prevent any possible
spoofing, received discovery messages must contain a proof that the
sender knows a common secret. We use the hash mix of the sending
node/namespace for this purpose, since it can be accessed directly by
all other namespaces in the kernel. Upon reception of a discovery
message, the receiver checks this proof against all the local
namespaces'hash_mix:es. If it finds a match, that, along with a
matching node id and cluster id, this is deemed sufficient proof that
the peer node in question is in a local namespace, and a wormhole can
be opened.

- We should also consider that TIPC is intended to be a cluster local
IPC mechanism (just like e.g. UNIX sockets) rather than a network
protocol, and hence we think it can justified to allow it to shortcut the
lower protocol layers.

Regarding traceability, we should notice that since commit 6c9081a3915d
("tipc: add loopback device tracking") it is possible to follow the node
internal packet flow by just activating tcpdump on the loopback
interface. This will be true even for this mechanism; by activating
tcpdump on the involved nodes' loopback interfaces their inter-name
space messaging can easily be tracked.

Suggested-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
---
 net/tipc/discover.c   |  10 ++++-
 net/tipc/msg.h        |  10 +++++
 net/tipc/name_distr.c |   2 +-
 net/tipc/node.c       | 100 ++++++++++++++++++++++++++++++++++++++++--
 net/tipc/node.h       |   4 +-
 net/tipc/socket.c     |   6 +--
 6 files changed, 121 insertions(+), 11 deletions(-)

Comments

Eric Dumazet Oct. 22, 2019, 2:40 a.m. UTC | #1
On 10/21/19 7:20 PM, Hoang Le wrote:
>  	n->net = net;
>  	n->capabilities = capabilities;
> +	n->pnet = NULL;
> +	for_each_net_rcu(tmp) {

This does not scale well, if say you have a thousand netns ?

> +		tn_peer = net_generic(tmp, tipc_net_id);
> +		if (!tn_peer)
> +			continue;
> +		/* Integrity checking whether node exists in namespace or not */
> +		if (tn_peer->net_id != tn->net_id)
> +			continue;
> +		if (memcmp(peer_id, tn_peer->node_id, NODE_ID_LEN))
> +			continue;
> +
> +		hash_chk = tn_peer->random;
> +		hash_chk ^= net_hash_mix(&init_net);

Why the xor with net_hash_mix(&init_net) is needed ?

> +		hash_chk ^= net_hash_mix(tmp);
> +		if (hash_chk ^ hash_mixes)
> +			continue;
> +		n->pnet = tmp;
> +		break;
> +	}


How can we set n->pnet without increasing netns ->count ?

Using check_net() later might trigger an use-after-free.
Hoang Le Oct. 22, 2019, 3:33 a.m. UTC | #2
Hi Eric,

Thanks for quick feedback.
See my inline answer.

Regards,
Hoang
-----Original Message-----
From: Eric Dumazet <eric.dumazet@gmail.com> 
Sent: Tuesday, October 22, 2019 9:41 AM
To: Hoang Le <hoang.h.le@dektech.com.au>; jon.maloy@ericsson.com; maloy@donjonn.com; tipc-discussion@lists.sourceforge.net; netdev@vger.kernel.org
Subject: Re: [net-next] tipc: improve throughput between nodes in netns


On 10/21/19 7:20 PM, Hoang Le wrote:
>  	n->net = net;
>  	n->capabilities = capabilities;
> +	n->pnet = NULL;
> +	for_each_net_rcu(tmp) {

This does not scale well, if say you have a thousand netns ?
[Hoang] This check execs only once at setup step. So we get no problem with huge namespaces.

> +		tn_peer = net_generic(tmp, tipc_net_id);
> +		if (!tn_peer)
> +			continue;
> +		/* Integrity checking whether node exists in namespace or not */
> +		if (tn_peer->net_id != tn->net_id)
> +			continue;
> +		if (memcmp(peer_id, tn_peer->node_id, NODE_ID_LEN))
> +			continue;
> +
> +		hash_chk = tn_peer->random;
> +		hash_chk ^= net_hash_mix(&init_net);

Why the xor with net_hash_mix(&init_net) is needed ?
[Hoang] We're trying to eliminate a sniff at injectable discovery message. 
Building hash-mixes as much as possible is to prevent fake discovery messages.

> +		hash_chk ^= net_hash_mix(tmp);
> +		if (hash_chk ^ hash_mixes)
> +			continue;
> +		n->pnet = tmp;
> +		break;
> +	}


How can we set n->pnet without increasing netns ->count ?
Using check_net() later might trigger an use-after-free.

[Hoang] In this case, peer node is down. I assume the tipc xmit function already bypassed these lines.
Eric Dumazet Oct. 22, 2019, 3:57 a.m. UTC | #3
On 10/21/19 8:33 PM, Hoang Le wrote:
> Hi Eric,
> 
> Thanks for quick feedback.
> See my inline answer.
> 
> Regards,
> Hoang
> -----Original Message-----
> From: Eric Dumazet <eric.dumazet@gmail.com> 
> Sent: Tuesday, October 22, 2019 9:41 AM
> To: Hoang Le <hoang.h.le@dektech.com.au>; jon.maloy@ericsson.com; maloy@donjonn.com; tipc-discussion@lists.sourceforge.net; netdev@vger.kernel.org
> Subject: Re: [net-next] tipc: improve throughput between nodes in netns
> 
> 
> On 10/21/19 7:20 PM, Hoang Le wrote:
>>  	n->net = net;
>>  	n->capabilities = capabilities;
>> +	n->pnet = NULL;
>> +	for_each_net_rcu(tmp) {
> 
> This does not scale well, if say you have a thousand netns ?
> [Hoang] This check execs only once at setup step. So we get no problem with huge namespaces.
> 
>> +		tn_peer = net_generic(tmp, tipc_net_id);
>> +		if (!tn_peer)
>> +			continue;
>> +		/* Integrity checking whether node exists in namespace or not */
>> +		if (tn_peer->net_id != tn->net_id)
>> +			continue;
>> +		if (memcmp(peer_id, tn_peer->node_id, NODE_ID_LEN))
>> +			continue;
>> +
>> +		hash_chk = tn_peer->random;
>> +		hash_chk ^= net_hash_mix(&init_net);
> 
> Why the xor with net_hash_mix(&init_net) is needed ?
> [Hoang] We're trying to eliminate a sniff at injectable discovery message. 
> Building hash-mixes as much as possible is to prevent fake discovery messages.
> 
>> +		hash_chk ^= net_hash_mix(tmp);
>> +		if (hash_chk ^ hash_mixes)
>> +			continue;
>> +		n->pnet = tmp;
>> +		break;
>> +	}
> 
> 
> How can we set n->pnet without increasing netns ->count ?
> Using check_net() later might trigger an use-after-free.
> 
> [Hoang] In this case, peer node is down. I assume the tipc xmit function already bypassed these lines.
> 

I assume nothing. I prefer evidences :)

It seems that the netns could go down later, you need some
kind of notifier to be able to purge queues/objects having a pointer to a dismantling netns.

Keeping pointers without proper refcount (get_net() or maybe_get_net()) is a recipe for disasters.

Patch
diff mbox series

diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index c138d68e8a69..338d402fcf39 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -38,6 +38,8 @@ 
 #include "node.h"
 #include "discover.h"
 
+#include <net/netns/hash.h>
+
 /* min delay during bearer start up */
 #define TIPC_DISC_INIT	msecs_to_jiffies(125)
 /* max delay if bearer has no links */
@@ -83,6 +85,7 @@  static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
 	struct tipc_net *tn = tipc_net(net);
 	u32 dest_domain = b->domain;
 	struct tipc_msg *hdr;
+	u32 hash;
 
 	hdr = buf_msg(skb);
 	tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
@@ -94,6 +97,10 @@  static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
 	msg_set_dest_domain(hdr, dest_domain);
 	msg_set_bc_netid(hdr, tn->net_id);
 	b->media->addr2msg(msg_media_addr(hdr), &b->addr);
+	hash = tn->random;
+	hash ^= net_hash_mix(&init_net);
+	hash ^= net_hash_mix(net);
+	msg_set_peer_net_hash(hdr, hash);
 	msg_set_node_id(hdr, tipc_own_id(net));
 }
 
@@ -242,7 +249,8 @@  void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
 	if (!tipc_in_scope(legacy, b->domain, src))
 		return;
 	tipc_node_check_dest(net, src, peer_id, b, caps, signature,
-			     &maddr, &respond, &dupl_addr);
+			     msg_peer_net_hash(hdr), &maddr, &respond,
+			     &dupl_addr);
 	if (dupl_addr)
 		disc_dupl_alert(b, src, &maddr);
 	if (!respond)
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index 0daa6f04ca81..a8d0f28094f2 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -973,6 +973,16 @@  static inline void msg_set_grp_remitted(struct tipc_msg *m, u16 n)
 	msg_set_bits(m, 9, 16, 0xffff, n);
 }
 
+static inline void msg_set_peer_net_hash(struct tipc_msg *m, u32 n)
+{
+	msg_set_word(m, 9, n);
+}
+
+static inline u32 msg_peer_net_hash(struct tipc_msg *m)
+{
+	return msg_word(m, 9);
+}
+
 /* Word 10
  */
 static inline u16 msg_grp_evt(struct tipc_msg *m)
diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c
index 836e629e8f4a..5feaf3b67380 100644
--- a/net/tipc/name_distr.c
+++ b/net/tipc/name_distr.c
@@ -146,7 +146,7 @@  static void named_distribute(struct net *net, struct sk_buff_head *list,
 	struct publication *publ;
 	struct sk_buff *skb = NULL;
 	struct distr_item *item = NULL;
-	u32 msg_dsz = ((tipc_node_get_mtu(net, dnode, 0) - INT_H_SIZE) /
+	u32 msg_dsz = ((tipc_node_get_mtu(net, dnode, 0, false) - INT_H_SIZE) /
 			ITEM_SIZE) * ITEM_SIZE;
 	u32 msg_rem = msg_dsz;
 
diff --git a/net/tipc/node.c b/net/tipc/node.c
index f2e3cf70c922..d830c2d1dbe3 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -45,6 +45,8 @@ 
 #include "netlink.h"
 #include "trace.h"
 
+#include <net/netns/hash.h>
+
 #define INVALID_NODE_SIG	0x10000
 #define NODE_CLEANUP_AFTER	300000
 
@@ -126,6 +128,7 @@  struct tipc_node {
 	struct timer_list timer;
 	struct rcu_head rcu;
 	unsigned long delete_at;
+	struct net *pnet;
 };
 
 /* Node FSM states and events:
@@ -184,7 +187,7 @@  static struct tipc_link *node_active_link(struct tipc_node *n, int sel)
 	return n->links[bearer_id].link;
 }
 
-int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
+int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel, bool connected)
 {
 	struct tipc_node *n;
 	int bearer_id;
@@ -194,6 +197,14 @@  int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
 	if (unlikely(!n))
 		return mtu;
 
+	/* Allow MAX_MSG_SIZE when building connection oriented message
+	 * if they are in the same core network
+	 */
+	if (n->pnet && connected) {
+		tipc_node_put(n);
+		return mtu;
+	}
+
 	bearer_id = n->active_links[sel & 1];
 	if (likely(bearer_id != INVALID_BEARER_ID))
 		mtu = n->links[bearer_id].mtu;
@@ -361,12 +372,16 @@  static void tipc_node_write_unlock(struct tipc_node *n)
 }
 
 static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
-					  u8 *peer_id, u16 capabilities)
+					  u8 *peer_id, u16 capabilities,
+					  u32 signature, u32 hash_mixes)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_node *n, *temp_node;
+	struct tipc_net *tn_peer;
 	struct tipc_link *l;
+	struct net *tmp;
 	int bearer_id;
+	u32 hash_chk;
 	int i;
 
 	spin_lock_bh(&tn->node_list_lock);
@@ -400,6 +415,25 @@  static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
 	memcpy(&n->peer_id, peer_id, 16);
 	n->net = net;
 	n->capabilities = capabilities;
+	n->pnet = NULL;
+	for_each_net_rcu(tmp) {
+		tn_peer = net_generic(tmp, tipc_net_id);
+		if (!tn_peer)
+			continue;
+		/* Integrity checking whether node exists in namespace or not */
+		if (tn_peer->net_id != tn->net_id)
+			continue;
+		if (memcmp(peer_id, tn_peer->node_id, NODE_ID_LEN))
+			continue;
+
+		hash_chk = tn_peer->random;
+		hash_chk ^= net_hash_mix(&init_net);
+		hash_chk ^= net_hash_mix(tmp);
+		if (hash_chk ^ hash_mixes)
+			continue;
+		n->pnet = tmp;
+		break;
+	}
 	kref_init(&n->kref);
 	rwlock_init(&n->lock);
 	INIT_HLIST_NODE(&n->hash);
@@ -979,7 +1013,7 @@  u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr)
 
 void tipc_node_check_dest(struct net *net, u32 addr,
 			  u8 *peer_id, struct tipc_bearer *b,
-			  u16 capabilities, u32 signature,
+			  u16 capabilities, u32 signature, u32 hash_mixes,
 			  struct tipc_media_addr *maddr,
 			  bool *respond, bool *dupl_addr)
 {
@@ -998,7 +1032,8 @@  void tipc_node_check_dest(struct net *net, u32 addr,
 	*dupl_addr = false;
 	*respond = false;
 
-	n = tipc_node_create(net, addr, peer_id, capabilities);
+	n = tipc_node_create(net, addr, peer_id, capabilities, signature,
+			     hash_mixes);
 	if (!n)
 		return;
 
@@ -1424,6 +1459,52 @@  static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
 	return -EMSGSIZE;
 }
 
+static void tipc_lxc_xmit(struct net *pnet, struct sk_buff_head *list)
+{
+	struct tipc_msg *hdr = buf_msg(skb_peek(list));
+	struct sk_buff_head inputq;
+
+	switch (msg_user(hdr)) {
+	case TIPC_LOW_IMPORTANCE:
+	case TIPC_MEDIUM_IMPORTANCE:
+	case TIPC_HIGH_IMPORTANCE:
+	case TIPC_CRITICAL_IMPORTANCE:
+		if (msg_connected(hdr) || msg_named(hdr)) {
+			spin_lock_init(&list->lock);
+			tipc_sk_rcv(pnet, list);
+			return;
+		}
+		if (msg_mcast(hdr)) {
+			skb_queue_head_init(&inputq);
+			tipc_sk_mcast_rcv(pnet, list, &inputq);
+			__skb_queue_purge(list);
+			skb_queue_purge(&inputq);
+			return;
+		}
+		return;
+	case MSG_FRAGMENTER:
+		if (tipc_msg_assemble(list)) {
+			skb_queue_head_init(&inputq);
+			tipc_sk_mcast_rcv(pnet, list, &inputq);
+			__skb_queue_purge(list);
+			skb_queue_purge(&inputq);
+		}
+		return;
+	case GROUP_PROTOCOL:
+	case CONN_MANAGER:
+		spin_lock_init(&list->lock);
+		tipc_sk_rcv(pnet, list);
+		return;
+	case LINK_PROTOCOL:
+	case NAME_DISTRIBUTOR:
+	case TUNNEL_PROTOCOL:
+	case BCAST_PROTOCOL:
+		return;
+	default:
+		return;
+	};
+}
+
 /**
  * tipc_node_xmit() is the general link level function for message sending
  * @net: the applicable net namespace
@@ -1439,6 +1520,7 @@  int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
 	struct tipc_link_entry *le = NULL;
 	struct tipc_node *n;
 	struct sk_buff_head xmitq;
+	bool node_up = false;
 	int bearer_id;
 	int rc;
 
@@ -1455,6 +1537,16 @@  int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
 		return -EHOSTUNREACH;
 	}
 
+	node_up = node_is_up(n);
+	if (node_up && n->pnet && check_net(n->pnet)) {
+		/* xmit inner linux container */
+		tipc_lxc_xmit(n->pnet, list);
+		if (likely(skb_queue_empty(list))) {
+			tipc_node_put(n);
+			return 0;
+		}
+	}
+
 	tipc_node_read_lock(n);
 	bearer_id = n->active_links[selector & 1];
 	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
diff --git a/net/tipc/node.h b/net/tipc/node.h
index 291d0ecd4101..2557d40fd417 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -75,7 +75,7 @@  u32 tipc_node_get_addr(struct tipc_node *node);
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
 void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,
 			  struct tipc_bearer *bearer,
-			  u16 capabilities, u32 signature,
+			  u16 capabilities, u32 signature, u32 hash_mixes,
 			  struct tipc_media_addr *maddr,
 			  bool *respond, bool *dupl_addr);
 void tipc_node_delete_links(struct net *net, int bearer_id);
@@ -92,7 +92,7 @@  void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr);
 void tipc_node_broadcast(struct net *net, struct sk_buff *skb);
 int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port);
 void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port);
-int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel);
+int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel, bool connected);
 bool tipc_node_is_up(struct net *net, u32 addr);
 u16 tipc_node_get_capabilities(struct net *net, u32 addr);
 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb);
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index d579b64705b1..d34bd2e36050 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -854,7 +854,7 @@  static int tipc_send_group_msg(struct net *net, struct tipc_sock *tsk,
 
 	/* Build message as chain of buffers */
 	__skb_queue_head_init(&pkts);
-	mtu = tipc_node_get_mtu(net, dnode, tsk->portid);
+	mtu = tipc_node_get_mtu(net, dnode, tsk->portid, false);
 	rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
 	if (unlikely(rc != dlen))
 		return rc;
@@ -1388,7 +1388,7 @@  static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 		return rc;
 
 	__skb_queue_head_init(&pkts);
-	mtu = tipc_node_get_mtu(net, dnode, tsk->portid);
+	mtu = tipc_node_get_mtu(net, dnode, tsk->portid, false);
 	rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
 	if (unlikely(rc != dlen))
 		return rc;
@@ -1526,7 +1526,7 @@  static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
 	sk_reset_timer(sk, &sk->sk_timer, jiffies + CONN_PROBING_INTV);
 	tipc_set_sk_state(sk, TIPC_ESTABLISHED);
 	tipc_node_add_conn(net, peer_node, tsk->portid, peer_port);
-	tsk->max_pkt = tipc_node_get_mtu(net, peer_node, tsk->portid);
+	tsk->max_pkt = tipc_node_get_mtu(net, peer_node, tsk->portid, true);
 	tsk->peer_caps = tipc_node_get_capabilities(net, peer_node);
 	__skb_queue_purge(&sk->sk_write_queue);
 	if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)