TUN-2714: New edge discovery. Connections try to reconnect to the same edge IP.

edgediscovery/allregions/region.go

@@ -0,0 +1,78 @@
+package allregions
+
+import (
+	"net"
+)
+
+// Region contains cloudflared edge addresses. The edge is partitioned into several regions for
+// redundancy purposes.
+type Region struct {
+	connFor map[*net.TCPAddr]UsedBy
+}
+
+// NewRegion creates a region with the given addresses, which are all unused.
+func NewRegion(addrs []*net.TCPAddr) Region {
+	// The zero value of UsedBy is Unused(), so we can just initialize the map's values with their
+	// zero values.
+	m := make(map[*net.TCPAddr]UsedBy)
+	for _, addr := range addrs {
+		m[addr] = Unused()
+	}
+	return Region{connFor: m}
+}
+
+// AddrUsedBy finds the address used by the given connection in this region.
+// Returns nil if the connection isn't using any IP.
+func (r *Region) AddrUsedBy(connID int) *net.TCPAddr {
+	for addr, used := range r.connFor {
+		if used.Used && used.ConnID == connID {
+			return addr
+		}
+	}
+	return nil
+}
+
+// AvailableAddrs counts how many unused addresses this region contains.
+func (r Region) AvailableAddrs() int {
+	n := 0
+	for _, usedby := range r.connFor {
+		if !usedby.Used {
+			n++
+		}
+	}
+	return n
+}
+
+// GetUnusedIP returns a random unused address in this region.
+// Returns nil if all addresses are in use.
+func (r Region) GetUnusedIP(excluding *net.TCPAddr) *net.TCPAddr {
+	for addr, usedby := range r.connFor {
+		if !usedby.Used && addr != excluding {
+			return addr
+		}
+	}
+	return nil
+}
+
+// Use the address, assigning it to a proxy connection.
+func (r Region) Use(addr *net.TCPAddr, connID int) {
+	r.connFor[addr] = InUse(connID)
+}
+
+// GetAnyAddress returns an arbitrary address from the region.
+func (r Region) GetAnyAddress() *net.TCPAddr {
+	for addr := range r.connFor {
+		return addr
+	}
+	return nil
+}
+
+// GiveBack the address, ensuring it is no longer assigned to an IP.
+// Returns true if the address is in this region.
+func (r Region) GiveBack(addr *net.TCPAddr) (ok bool) {
+	if _, ok := r.connFor[addr]; !ok {
+		return false
+	}
+	r.connFor[addr] = Unused()
+	return true
+}