From 934993137199ffb56fef50664f87e71cdb3471b0 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Tue, 25 Oct 2011 15:14:46 -0400 Subject: tipc: Ensure broadcast link re-acquires node after link failure Fix a bug that can prevent TIPC from sending broadcast messages to a node if contact with the node is lost and then regained. The problem occurs if the broadcast link first clears the flag indicating the node is part of the link's distribution set (when it loses contact with the node), and later fails to restore the flag (when contact is regained); restoration fails if contact with the node is regained by implicit unicast link activation triggered by the arrival of a data message, rather than explicitly by the arrival of a link activation message. The broadcast link now uses separate fields to track whether a node is theoretically capable of receiving broadcast messages versus whether it is actually part of the link's distribution set. The former member is updated by the receipt of link protocol messages, which can occur at any time; the latter member is updated only when contact with the node is gained or lost. This change also permits the simplification of several conditional expressions since the broadcast link's "supported" field can now only be set if there are working links to the associated node. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/node.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/tipc/node.h') diff --git a/net/tipc/node.h b/net/tipc/node.h index 0b1c5f8b6996..90689f487615 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -62,6 +62,7 @@ * @link_cnt: number of links to node * @permit_changeover: non-zero if node has redundant links to this system * @bclink: broadcast-related info + * @supportable: non-zero if node supports TIPC b'cast link capability * @supported: non-zero if node supports TIPC b'cast capability * @acked: sequence # of last outbound b'cast message acknowledged by node * @last_in: sequence # of last in-sequence b'cast message received from node @@ -86,7 +87,8 @@ struct tipc_node { int block_setup; int permit_changeover; struct { - int supported; + u8 supportable; + u8 supported; u32 acked; u32 last_in; u32 gap_after; -- cgit v1.2.1 From 7a54d4a99dcbbfdf1d4550faa19b615091137953 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Thu, 27 Oct 2011 14:17:53 -0400 Subject: tipc: Major redesign of broadcast link ACK/NACK algorithms Completely redesigns broadcast link ACK and NACK mechanisms to prevent spurious retransmit requests in dual LAN networks, and to prevent the broadcast link from stalling due to the failure of a receiving node to acknowledge receiving a broadcast message or request its retransmission. Note: These changes only impact the timing of when ACK and NACK messages are sent, and not the basic broadcast link protocol itself, so inter- operability with nodes using the "classic" algorithms is maintained. The revised algorithms are as follows: 1) An explicit ACK message is still sent after receiving 16 in-sequence messages, and implicit ACK information continues to be carried in other unicast link message headers (including link state messages). However, the timing of explicit ACKs is now based on the receiving node's absolute network address rather than its relative network address to ensure that the failure of another node does not delay the ACK beyond its 16 message target. 2) A NACK message is now typically sent only when a message gap persists for two consecutive incoming link state messages; this ensures that a suspected gap is not confirmed until both LANs in a dual LAN network have had an opportunity to deliver the message, thereby preventing spurious NACKs. A NACK message can also be generated by the arrival of a single link state message, if the deferred queue is so big that the current message gap cannot be the result of "normal" mis-ordering due to the use of dual LANs (or one LAN using a bonded interface). Since link state messages typically arrive at different nodes at different times the problem of multiple nodes issuing identical NACKs simultaneously is inherently avoided. 3) Nodes continue to "peek" at NACK messages sent by other nodes. If another node requests retransmission of a message gap suspected (but not yet confirmed) by the peeking node, the peeking node forgets about the gap and does not generate a duplicate retransmit request. (If the peeking node subsequently fails to receive the lost message, later link state messages will cause it to rediscover and confirm the gap and send another NACK.) 4) Message gap "equality" is now determined by the start of the gap only. This is sufficient to deal with the most common cases of message loss, and eliminates the need for complex end of gap computations. 5) A peeking node no longer tries to determine whether it should send a complementary NACK, since the most common cases of message loss don't require it to be sent. Consequently, the node no longer examines the "broadcast tag" field of a NACK message when peeking. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/node.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'net/tipc/node.h') diff --git a/net/tipc/node.h b/net/tipc/node.h index 90689f487615..c88ce64f8a31 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -66,9 +66,9 @@ * @supported: non-zero if node supports TIPC b'cast capability * @acked: sequence # of last outbound b'cast message acknowledged by node * @last_in: sequence # of last in-sequence b'cast message received from node - * @gap_after: sequence # of last message not requiring a NAK request - * @gap_to: sequence # of last message requiring a NAK request - * @nack_sync: counter that determines when NAK requests should be sent + * @last_sent: sequence # of last b'cast message sent by node + * @oos_state: state tracker for handling OOS b'cast messages + * @deferred_size: number of OOS b'cast messages in deferred queue * @deferred_head: oldest OOS b'cast message received from node * @deferred_tail: newest OOS b'cast message received from node * @defragm: list of partially reassembled b'cast message fragments from node @@ -91,9 +91,9 @@ struct tipc_node { u8 supported; u32 acked; u32 last_in; - u32 gap_after; - u32 gap_to; - u32 nack_sync; + u32 last_sent; + u32 oos_state; + u32 deferred_size; struct sk_buff *deferred_head; struct sk_buff *deferred_tail; struct sk_buff *defragm; -- cgit v1.2.1 From 1ec2bb08407b377e5954b3f9479c2bf67fc925a9 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Thu, 27 Oct 2011 15:03:24 -0400 Subject: tipc: Remove obsolete broadcast tag capability Eliminates support for the broadcast tag field, which is no longer used by broadcast link NACK messages. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/node.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/tipc/node.h') diff --git a/net/tipc/node.h b/net/tipc/node.h index c88ce64f8a31..e1b78a2199c2 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -114,8 +114,6 @@ static inline unsigned int tipc_hashfn(u32 addr) return addr & (NODE_HTABLE_SIZE - 1); } -extern u32 tipc_own_tag; - struct tipc_node *tipc_node_find(u32 addr); struct tipc_node *tipc_node_create(u32 addr); void tipc_node_delete(struct tipc_node *n_ptr); -- cgit v1.2.1 From fc0eea691a06ba8516795fb7a198239fb9db1cfc Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Fri, 28 Oct 2011 16:26:41 -0400 Subject: tipc: Introduce node signature field in neighbor discovery message Adds support for the new "node signature" in neighbor discovery messages, which is a 16 bit identifier chosen randomly when TIPC is initialized. This field makes it possible for nodes receiving a neighbor discovery message to detect if multiple neighboring nodes are using the same network address (i.e. ), even when the messages are arriving on different interfaces. This first phase of node signature support creates the signature, incorporates it into outgoing neighbor discovery messages, and tracks the signature used by valid neighbors. An upcoming patch builds on this foundation to implement the improved duplicate neighbor detection checking. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/node.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net/tipc/node.h') diff --git a/net/tipc/node.h b/net/tipc/node.h index e1b78a2199c2..7bf526af1dfb 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -42,6 +42,11 @@ #include "net.h" #include "bearer.h" +/* + * Out-of-range value for node signature + */ +#define INVALID_NODE_SIG 0x10000 + /* Flags used to block (re)establishment of contact with a neighboring node */ #define WAIT_PEER_DOWN 0x0001 /* wait to see that peer's links are down */ @@ -61,6 +66,7 @@ * @block_setup: bit mask of conditions preventing link establishment to node * @link_cnt: number of links to node * @permit_changeover: non-zero if node has redundant links to this system + * @signature: node instance identifier * @bclink: broadcast-related info * @supportable: non-zero if node supports TIPC b'cast link capability * @supported: non-zero if node supports TIPC b'cast capability @@ -86,6 +92,7 @@ struct tipc_node { int working_links; int block_setup; int permit_changeover; + u32 signature; struct { u8 supportable; u8 supported; -- cgit v1.2.1 From a635b46bd884efc1fc98819cb5a200da255d575c Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Fri, 4 Nov 2011 11:54:43 -0400 Subject: tipc: Hide internal details of node table implementation Relocates information about the size of TIPC's node table index and its associated hash function, since only node subsystem routines need to have access to this information. Note that these changes are essentially cosmetic in nature, and have no impact on the actual operation of TIPC. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/node.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'net/tipc/node.h') diff --git a/net/tipc/node.h b/net/tipc/node.h index 7bf526af1dfb..72561c971d67 100644 --- a/net/tipc/node.h +++ b/net/tipc/node.h @@ -107,20 +107,8 @@ struct tipc_node { } bclink; }; -#define NODE_HTABLE_SIZE 512 extern struct list_head tipc_node_list; -/* - * A trivial power-of-two bitmask technique is used for speed, since this - * operation is done for every incoming TIPC packet. The number of hash table - * entries has been chosen so that no hash chain exceeds 8 nodes and will - * usually be much smaller (typically only a single node). - */ -static inline unsigned int tipc_hashfn(u32 addr) -{ - return addr & (NODE_HTABLE_SIZE - 1); -} - struct tipc_node *tipc_node_find(u32 addr); struct tipc_node *tipc_node_create(u32 addr); void tipc_node_delete(struct tipc_node *n_ptr); -- cgit v1.2.1