From 934993137199ffb56fef50664f87e71cdb3471b0 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Tue, 25 Oct 2011 15:14:46 -0400 Subject: [PATCH] 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/link.c | 5 +++-- net/tipc/node.c | 3 ++- net/tipc/node.h | 4 +++- 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/tipc/link.c b/net/tipc/link.c index 4ea6cad11746..3405f560a84d 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1502,6 +1502,7 @@ static void link_retransmit_failure(struct tipc_link *l_ptr, tipc_addr_string_fill(addr_string, n_ptr->addr); info("Multicast link info for %s\n", addr_string); + info("Supportable: %d, ", n_ptr->bclink.supportable); info("Supported: %d, ", n_ptr->bclink.supported); info("Acked: %u\n", n_ptr->bclink.acked); info("Last in: %u, ", n_ptr->bclink.last_in); @@ -1736,7 +1737,7 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr) /* Release acked messages */ - if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported) + if (n_ptr->bclink.supported) tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg)); crs = l_ptr->first_out; @@ -2126,7 +2127,7 @@ static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf) } else { l_ptr->max_pkt = l_ptr->max_pkt_target; } - l_ptr->owner->bclink.supported = (max_pkt_info != 0); + l_ptr->owner->bclink.supportable = (max_pkt_info != 0); /* Synchronize broadcast link info, if not done previously */ diff --git a/net/tipc/node.c b/net/tipc/node.c index 6b226faad89f..9196f943b835 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -306,8 +306,9 @@ static void node_established_contact(struct tipc_node *n_ptr) /* Syncronize broadcast acks */ n_ptr->bclink.acked = tipc_bclink_get_last_sent(); - if (n_ptr->bclink.supported) { + if (n_ptr->bclink.supportable) { tipc_bclink_add_node(n_ptr->addr); + n_ptr->bclink.supported = 1; if (n_ptr->addr < tipc_own_addr) tipc_own_tag++; } 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; -- 2.20.1