func (n *Node) receiveVersion(version string) {
// If this is not a new incoming connection, error.
if n.conn.State != connect.ConnStateInitialIncoming {
n.conn.Close()
return
}
// Verify that we support this version.
found := false
for _, supported := range connect.Versions {
if version == supported {
found = true
break
}
}
if !found {
n.conn.Close()
return
}
// Set this connection's protocol version.
n.conn.Version = version
// Send our capabilities list.
n.conn.WriteLine(connect.MakeCap(connect.Capabilities))
// Move into capabilities negotiation state.
n.conn.State = connect.ConnStateCapabilityNegotiationIncoming
}
func (n *Node) receiveCap(capabilities []string) {
switch n.conn.State {
case connect.ConnStateCapabilityNegotiationOutgoing:
// We're expecting a list of supporting capabilities,
// and need to send back the subset we support.
var shared []string
for _, remoteCapability := range capabilities {
for _, capability := range connect.Capabilities {
if capability == remoteCapability {
shared = append(shared, capability)
break
}
}
}
// Set this connection's enabled capabilities.
n.conn.Capabilities = shared
// Send back the picked capability set.
n.conn.WriteLine(connect.MakeCap(shared))
// Send our degraded notification.
n.conn.WriteLine(connect.MakeDegraded(Degraded))
// Move into degraded notification state.
n.conn.State = connect.ConnStateDegradedNotification
case connect.ConnStateCapabilityNegotiationIncoming:
// We're expecting a list of selected capabilities.
// Verify that we have the capabilities they send.
for _, selected := range capabilities {
matched := false
for _, capability := range connect.Capabilities {
if capability == selected {
matched = true
break
}
}
if !matched {
// Invalid capability.
n.conn.Close()
return
}
}
// Set this connection's enabled capabilities.
n.conn.Capabilities = capabilities
// Send our degraded notification.
n.conn.WriteLine(connect.MakeDegraded(Degraded))
// Move into degraded notification state.
n.conn.State = connect.ConnStateDegradedNotification
default:
// Invalid state for this message.
n.conn.Close()
}
}