From 63e7f1ac2855ba56f15d8189694ca9bd16ae4107 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Thu, 27 Oct 2011 16:43:09 -0400 Subject: tipc: Prevent loss of fragmented messages over broadcast link Modifies broadcast link so that an incoming fragmented message is not lost if reassembly cannot begin because there currently is no buffer big enough to hold the entire reassembled message. The broadcast link now ignores the first fragment completely, which causes the sending node to retransmit the first fragment so that reassembly can be re-attempted. Previously, the sender would have had no reason to retransmit the 1st fragment, so we would never have a chance to re-try the allocation. To do this cleanly without duplicaton, a new bclink_accept_pkt() function is introduced. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/bcast.c | 64 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 42 insertions(+), 22 deletions(-) (limited to 'net') diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c index a9b7132d34f2..41ecf313073c 100644 --- a/net/tipc/bcast.c +++ b/net/tipc/bcast.c @@ -389,7 +389,33 @@ exit: return res; } -/** +/* + * bclink_accept_pkt - accept an incoming, in-sequence broadcast packet + * + * Called with both sending node's lock and bc_lock taken. + */ + +static void bclink_accept_pkt(struct tipc_node *node, u32 seqno) +{ + bclink_update_last_sent(node, seqno); + node->bclink.last_in = seqno; + node->bclink.oos_state = 0; + bcl->stats.recv_info++; + + /* + * Unicast an ACK periodically, ensuring that + * all nodes in the cluster don't ACK at the same time + */ + + if (((seqno - tipc_own_addr) % TIPC_MIN_LINK_WIN) == 0) { + tipc_link_send_proto_msg( + node->active_links[node->addr & 1], + STATE_MSG, 0, 0, 0, 0, 0); + bcl->stats.sent_acks++; + } +} + +/* * tipc_bclink_recv_pkt - receive a broadcast packet, and deliver upwards * * tipc_net_lock is read_locked, no other locks set @@ -443,29 +469,12 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf) next_in = mod(node->bclink.last_in + 1); if (likely(seqno == next_in)) { - bclink_update_last_sent(node, seqno); receive: - node->bclink.last_in = seqno; - node->bclink.oos_state = 0; - - spin_lock_bh(&bc_lock); - bcl->stats.recv_info++; - - /* - * Unicast an ACK periodically, ensuring that - * all nodes in the cluster don't ACK at the same time - */ - - if (((seqno - tipc_own_addr) % TIPC_MIN_LINK_WIN) == 0) { - tipc_link_send_proto_msg( - node->active_links[node->addr & 1], - STATE_MSG, 0, 0, 0, 0, 0); - bcl->stats.sent_acks++; - } - /* Deliver message to destination */ if (likely(msg_isdata(msg))) { + spin_lock_bh(&bc_lock); + bclink_accept_pkt(node, seqno); spin_unlock_bh(&bc_lock); tipc_node_unlock(node); if (likely(msg_mcast(msg))) @@ -473,24 +482,35 @@ receive: else buf_discard(buf); } else if (msg_user(msg) == MSG_BUNDLER) { + spin_lock_bh(&bc_lock); + bclink_accept_pkt(node, seqno); bcl->stats.recv_bundles++; bcl->stats.recv_bundled += msg_msgcnt(msg); spin_unlock_bh(&bc_lock); tipc_node_unlock(node); tipc_link_recv_bundle(buf); } else if (msg_user(msg) == MSG_FRAGMENTER) { + int ret = tipc_link_recv_fragment(&node->bclink.defragm, + &buf, &msg); + if (ret < 0) + goto unlock; + spin_lock_bh(&bc_lock); + bclink_accept_pkt(node, seqno); bcl->stats.recv_fragments++; - if (tipc_link_recv_fragment(&node->bclink.defragm, - &buf, &msg)) + if (ret > 0) bcl->stats.recv_fragmented++; spin_unlock_bh(&bc_lock); tipc_node_unlock(node); tipc_net_route_msg(buf); } else if (msg_user(msg) == NAME_DISTRIBUTOR) { + spin_lock_bh(&bc_lock); + bclink_accept_pkt(node, seqno); spin_unlock_bh(&bc_lock); tipc_node_unlock(node); tipc_named_recv(buf); } else { + spin_lock_bh(&bc_lock); + bclink_accept_pkt(node, seqno); spin_unlock_bh(&bc_lock); tipc_node_unlock(node); buf_discard(buf); -- cgit v1.2.1