Merge pull request 'Take over the found tunnel: its key, its port, its peers; stop it, never flush (hq ADR 0105)' (#24) from feat/adopt-the-tunnel into main

internal/bootstrap/bootstrap.go

@@ -36,6 +36,7 @@ import (
 	"time"
 
 	"github.com/novox/mesh-host/internal/firewall"
+	"github.com/novox/mesh-host/internal/tunnel"
 )
 
 // Step names one stage. A failure says which one, because "the bootstrap failed" is a sentence
@@ -201,6 +202,11 @@ type Options struct {
 	// until each module is taken, its firewall stays in force, and the mesh guards its own ports
 	// in a table that only refuses. Without it, a machine in use is refused.
 	Adopted bool
+	// Tunnel names the found tunnel's interface an adopted hub takes over (novox/hq ADR 0105), when
+	// more than one is up and the machine cannot say which. Empty finds the one that is up. Once
+	// found, the tunnel's port is the hub's and its range the private network's; --hub-port and
+	// --overlay-range may agree with it or be left unsaid.
+	Tunnel string
 }
 
 // pivots reports whether this run goes past the foundation.
@@ -311,6 +317,9 @@ type Result struct {
 	// Filter is the packet filter chosen for when the node converges; an adopted genesis loads
 	// none, and the flip assigns this one.
 	Filter string `json:"filter-on-converge,omitempty"`
+	// Tunnel is the found tunnel an adopted genesis takes over (novox/hq ADR 0105): what was read
+	// from it, never its key.
+	Tunnel *tunnel.Found `json:"tunnel,omitempty"`
 }
 
 // Run performs the bootstrap, saying what it is doing as it goes.
@@ -394,6 +403,23 @@ func Run(ctx context.Context, o Options, d Deps, say func(string)) (Result, erro
 		}
 		result.Firewall = string(kind)
 		say("  adopted           what is on this machine is kept; its firewall (" + string(kind) + ") stays in force")
+
+		// The tunnel the predecessor left, which the private network takes over (novox/hq ADR
+		// 0105): its port is the hub's and its range is the mesh's from here on, so both are
+		// settled before the ports are checked free and the bundle rewritten.
+		found, err := TakeTheTunnel(&o, d.Run)
+		if err != nil {
+			return result, failed(StepPreflight, err)
+		}
+		if found != nil {
+			result.Tunnel = found
+			result.Ports = o.Ports
+			say(fmt.Sprintf("  tunnel            %s — the private network takes it over: its port %d is "+
+				"the hub's, its range %s the mesh's, and its %d peer(s) are carried until they enrol",
+				found.Interface, found.Port, found.Range, len(found.Peers)))
+		} else {
+			say("  tunnel            none up on this machine; the private network is raised on its own port and range")
+		}
 	}
 
 	sys, err := WorkOutSystem(ctx, d.Run, o.System)