142 lines
4.4 KiB
Go
142 lines
4.4 KiB
Go
package allregions
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import (
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"fmt"
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"math/rand"
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"github.com/rs/zerolog"
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)
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// Regions stores Cloudflare edge network IPs, partitioned into two regions.
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// This is NOT thread-safe. Users of this package should use it with a lock.
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type Regions struct {
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region1 Region
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region2 Region
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}
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// ------------------------------------
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// Constructors
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// ------------------------------------
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// ResolveEdge resolves the Cloudflare edge, returning all regions discovered.
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func ResolveEdge(log *zerolog.Logger, region string, overrideIPVersion ConfigIPVersion) (*Regions, error) {
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edgeAddrs, err := edgeDiscovery(log, getRegionalServiceName(region))
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if err != nil {
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return nil, err
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}
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if len(edgeAddrs) < 2 {
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return nil, fmt.Errorf("expected at least 2 Cloudflare Regions regions, but SRV only returned %v", len(edgeAddrs))
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}
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return &Regions{
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region1: NewRegion(edgeAddrs[0], overrideIPVersion),
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region2: NewRegion(edgeAddrs[1], overrideIPVersion),
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}, nil
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}
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// StaticEdge creates a list of edge addresses from the list of hostnames.
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// Mainly used for testing connectivity.
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func StaticEdge(hostnames []string, log *zerolog.Logger) (*Regions, error) {
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resolved := ResolveAddrs(hostnames, log)
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if len(resolved) == 0 {
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return nil, fmt.Errorf("failed to resolve any edge address")
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}
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return NewNoResolve(resolved), nil
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}
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// NewNoResolve doesn't resolve the edge. Instead it just uses the given addresses.
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// You probably only need this for testing.
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func NewNoResolve(addrs []*EdgeAddr) *Regions {
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region1 := make([]*EdgeAddr, 0)
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region2 := make([]*EdgeAddr, 0)
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for i, v := range addrs {
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if i%2 == 0 {
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region1 = append(region1, v)
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} else {
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region2 = append(region2, v)
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}
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}
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return &Regions{
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region1: NewRegion(region1, Auto),
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region2: NewRegion(region2, Auto),
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}
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}
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// ------------------------------------
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// Methods
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// ------------------------------------
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// GetAnyAddress returns an arbitrary address from the larger region.
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func (rs *Regions) GetAnyAddress() *EdgeAddr {
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if addr := rs.region1.GetAnyAddress(); addr != nil {
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return addr
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}
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return rs.region2.GetAnyAddress()
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}
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// AddrUsedBy finds the address used by the given connection.
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// Returns nil if the connection isn't using an address.
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func (rs *Regions) AddrUsedBy(connID int) *EdgeAddr {
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if addr := rs.region1.AddrUsedBy(connID); addr != nil {
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return addr
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}
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return rs.region2.AddrUsedBy(connID)
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}
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// GetUnusedAddr gets an unused addr from the edge, excluding the given addr. Prefer to use addresses
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// evenly across both regions.
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func (rs *Regions) GetUnusedAddr(excluding *EdgeAddr, connID int) *EdgeAddr {
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// If both regions have the same number of available addrs, lets randomise which one
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// we pick. The rest of this algorithm will continue to make sure we always use addresses
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// evenly across both regions.
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if rs.region1.AvailableAddrs() == rs.region2.AvailableAddrs() {
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regions := []Region{rs.region1, rs.region2}
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firstChoice := rand.Intn(2)
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return getAddrs(excluding, connID, ®ions[firstChoice], ®ions[1-firstChoice])
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}
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if rs.region1.AvailableAddrs() > rs.region2.AvailableAddrs() {
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return getAddrs(excluding, connID, &rs.region1, &rs.region2)
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}
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return getAddrs(excluding, connID, &rs.region2, &rs.region1)
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}
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// getAddrs tries to grab address form `first` region, then `second` region
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// this is an unrolled loop over 2 element array
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func getAddrs(excluding *EdgeAddr, connID int, first *Region, second *Region) *EdgeAddr {
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addr := first.AssignAnyAddress(connID, excluding)
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if addr != nil {
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return addr
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}
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addr = second.AssignAnyAddress(connID, excluding)
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if addr != nil {
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return addr
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}
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return nil
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}
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// AvailableAddrs returns how many edge addresses aren't used.
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func (rs *Regions) AvailableAddrs() int {
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return rs.region1.AvailableAddrs() + rs.region2.AvailableAddrs()
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}
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// GiveBack the address so that other connections can use it.
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// Returns true if the address is in this edge.
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func (rs *Regions) GiveBack(addr *EdgeAddr, hasConnectivityError bool) bool {
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if found := rs.region1.GiveBack(addr, hasConnectivityError); found {
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return found
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}
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return rs.region2.GiveBack(addr, hasConnectivityError)
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}
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// Return regionalized service name if `region` isn't empty, otherwise return the global service name for origintunneld
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func getRegionalServiceName(region string) string {
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if region != "" {
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return region + "-" + srvService // Example: `us-v2-origintunneld`
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}
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return srvService // Global service is just `v2-origintunneld`
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}
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