Remove TUNNEL_MAP lookup

[vincentmli]

per discussion #17106 (comment), TUNNEL_MAP lookup is a fallback path for node pod cidr prefix, we could add the pod cidr prefix in IPCACHE and completely remove TUNNEL_MAP

[vincentmli]

the code to add pod cidr in tunnel_map

pkg/datapath/linux/node.go

  92 // updateTunnelMapping is called when a node update is received while running
  93 // with encapsulation mode enabled. The CIDR and IP of both the old and new
  94 // node are provided as context. The caller expects the tunnel mapping in the
  95 // datapath to be updated.
  96 func updateTunnelMapping(oldCIDR, newCIDR *cidr.CIDR, oldIP, newIP net.IP, firstAddition, encapEnabled bool, oldEncryptKey, newEnc     ryptKey uint8) {
  97         if !encapEnabled {
  98                 // When the protocol family is disabled, the initial node addition will
  99                 // trigger a deletion to clean up leftover entries. The deletion happens
 100                 // in quiet mode as we don't know whether it exists or not
 101                 if newCIDR != nil && firstAddition {
 102                         deleteTunnelMapping(newCIDR, true)
 103                 }
 104 
 105                 return
 106         }
 107 
 108         if cidrNodeMappingUpdateRequired(oldCIDR, newCIDR, oldIP, newIP, oldEncryptKey, newEncryptKey) {
 109                 log.WithFields(logrus.Fields{
 110                         logfields.IPAddr: newIP,
 111                         "allocCIDR":      newCIDR,
 112                 }).Debug("Updating tunnel map entry")
 113 
 114                 if err := tunnel.TunnelMap.SetTunnelEndpoint(newEncryptKey, newCIDR.IP, newIP); err != nil {
 115                         log.WithError(err).WithFields(logrus.Fields{
 116                                 "allocCIDR": newCIDR,
 117                         }).Error("bpf: Unable to update in tunnel endpoint map")
 118                 }
 119         }

it seems to be matter of replacing tunnel.TunnelMap.SetTunnelEndpoint with ipcache.Upsert, the question is what identity we should use for pod cidr prefix, @joestringer, do you have any suggestion on the identity?

[joestringer]

With #19765 / #20117 we should be able to remove the requirement to specify the identity.

[vincentmli]

ok, I will wait then till they are merged

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This issue has been automatically marked as stale because it has not
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[vincentmli]

no stale

[github-actions]

This issue has been automatically marked as stale because it has not
had recent activity. It will be closed if no further activity occurs.