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tipc: fix unexpected link reset due to discovery messages 

This unexpected behavior is observed:

node 1                    | node 2
------                    | ------
link is established       | link is established
reboot                    | link is reset
up                        | send discovery message
receive discovery message |
link is established       | link is established
send discovery message    |
                          | receive discovery message
                          | link is reset (unexpected)
                          | send reset message
link is reset             |

It is due to delayed re-discovery as described in function
tipc_node_check_dest(): "this link endpoint has already reset
and re-established contact with the peer, before receiving a
discovery message from that node."

However, commit 598411d70f has changed the condition for calling
tipc_node_link_down() which was the acceptance of new media address.

This commit fixes this by restoring the old and correct behavior.

Fixes: 598411d70f ("tipc: make resetting of links non-atomic")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tung Nguyen 2023-01-05 06:02:51 +00:00 committed by David S. Miller
parent eea8ce81fb
commit c244c092f1
1 changed files with 8 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
net/tipc/node.c
View File

@ -1179,8 +1179,9 @@ void tipc_node_check_dest(struct net *net, u32 addr,
bool addr_match = false;
bool sign_match = false;
bool link_up = false;
bool link_is_reset = false;
bool accept_addr = false;
bool reset = true;
bool reset = false;
char *if_name;
unsigned long intv;
u16 session;
@ -1200,14 +1201,14 @@ void tipc_node_check_dest(struct net *net, u32 addr,
/* Prepare to validate requesting node's signature and media address */
l = le->link;
link_up = l && tipc_link_is_up(l);
link_is_reset = l && tipc_link_is_reset(l);
addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
sign_match = (signature == n->signature);
/* These three flags give us eight permutations: */
if (sign_match && addr_match && link_up) {
/* All is fine. Do nothing. */
reset = false;
/* All is fine. Ignore requests. */
/* Peer node is not a container/local namespace */
if (!n->peer_hash_mix)
n->peer_hash_mix = hash_mixes;
@ -1232,6 +1233,7 @@ void tipc_node_check_dest(struct net *net, u32 addr,
*/
accept_addr = true;
*respond = true;
reset = true;
} else if (!sign_match && addr_match && link_up) {
/* Peer node rebooted. Two possibilities:
* - Delayed re-discovery; this link endpoint has already
@ -1263,6 +1265,7 @@ void tipc_node_check_dest(struct net *net, u32 addr,
n->signature = signature;
accept_addr = true;
*respond = true;
reset = true;
}
if (!accept_addr)
@ -1291,6 +1294,7 @@ void tipc_node_check_dest(struct net *net, u32 addr,
tipc_link_fsm_evt(l, LINK_RESET_EVT);
if (n->state == NODE_FAILINGOVER)
tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
link_is_reset = tipc_link_is_reset(l);
le->link = l;
n->link_cnt++;
tipc_node_calculate_timer(n, l);
@ -1303,7 +1307,7 @@ void tipc_node_check_dest(struct net *net, u32 addr,
memcpy(&le->maddr, maddr, sizeof(*maddr));
exit:
tipc_node_write_unlock(n);
if (reset && l && !tipc_link_is_reset(l))
if (reset && !link_is_reset)
tipc_node_link_down(n, b->identity, false);
tipc_node_put(n);
}