Native SCTP re-transmission and ABORT messages not sent when expected
Issue
- With SCTP tunables like:
net.sctp.rto_max = 500
net.sctp.rto_min = 150
net.sctp.rto_initial = 400
net.sctp.association_max_retrans = 10
net.sctp.path_max_retrans = 5
net.sctp.pf_retrans = 2147483647
net.sctp.hb_interval = 1000
Packet capture of an assoc shows:
75 19.812263 192.168.0.104 → 10.0.0.140 SCTP 100 HEARTBEAT # HB to 140 path ACKed in next frame
76 19.821973 10.0.0.140 → 192.168.0.104 SCTP 100 HEARTBEAT_ACK
80 20.765297 172.29.98.104 → 10.0.0.156 SCTP 100 HEARTBEAT # HB to 156 path ACKed in next frame
81 20.774524 10.0.0.156 → 172.29.98.104 SCTP 100 HEARTBEAT_ACK
82 21.105094 10.0.0.140 → 192.168.0.104 SCTP 100 ABORT
83 21.184261 192.168.0.104 → 10.0.0.140 SCTP 100 HEARTBEAT # initial HB to 140 path
84 21.194010 10.0.0.140 → 192.168.0.104 SCTP 62 ABORT
85 22.452250 172.29.98.104 → 10.0.0.156 SCTP 100 HEARTBEAT # initial HB to 156 path
86 22.461463 10.0.0.156 → 172.29.98.104 SCTP 62 ABORT
87 22.480275 192.168.0.104 → 10.0.0.140 SCTP 100 HEARTBEAT # 1st unacked HB to 140 path, 1st on assoc
88 22.489981 10.0.0.140 → 192.168.0.104 SCTP 62 ABORT
89 24.024299 192.168.0.104 → 10.0.0.140 SCTP 100 HEARTBEAT # 2nd unacked HB to 140 path, 2nd on assoc
90 24.034025 10.0.0.140 → 192.168.0.104 SCTP 62 ABORT
91 24.772292 172.29.98.104 → 10.0.0.156 SCTP 100 HEARTBEAT # 1st unacked HB to 156 path, 3rd on assoc
92 24.781483 10.0.0.156 → 172.29.98.104 SCTP 62 ABORT
- We expected 3 heartbeats followed by
ABORT, as that is the time innet.sctp.rto_max. Why are we not sendingABORT?
Environment
- Red Hat Enterprise Linux 6
- SCTP (Streaming Control Transmission Protocol)
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