Handle port bindings correctly when using 127.0.0.1

closes pterodactyl/panel#2307

environment/allocations.go

@@ -3,6 +3,7 @@ package environment
 import (
 	"fmt"
 	"github.com/docker/go-connections/nat"
+	"github.com/pterodactyl/wings/config"
 	"strconv"
 )
 
@@ -25,6 +26,8 @@ type Allocations struct {
 // Converts the server allocation mappings into a format that can be understood by Docker. While
 // we do strive to support multiple environments, using Docker's standardized format for the
 // bindings certainly makes life a little easier for managing things.
+//
+// You'll want to use DockerBindings() if you need to re-map 127.0.0.1 to the Docker interface.
 func (a *Allocations) Bindings() nat.PortMap {
 	var out = nat.PortMap{}
 
@@ -50,16 +53,47 @@ func (a *Allocations) Bindings() nat.PortMap {
 	return out
 }
 
+// Returns the bindings for the server in a way that is supported correctly by Docker. This replaces
+// any reference to 127.0.0.1 with the IP of the pterodactyl0 network interface which will allow the
+// server to operate on a local address while still being accessible by other containers.
+func (a *Allocations) DockerBindings() nat.PortMap {
+	iface := config.Get().Docker.Network.Interface
+
+	out := a.Bindings()
+	// Loop over all of the bindings for this container, and convert any that reference 127.0.0.1
+	// to use the pterodactyl0 network interface IP, as that is the true local for what people are
+	// trying to do when creating servers.
+	for p, binds := range out {
+		for i, alloc := range binds {
+			if alloc.HostIP != "127.0.0.1" {
+				continue
+			}
+
+			// If using ISPN just delete the local allocation from the server.
+			if config.Get().Docker.Network.ISPN {
+				out[p] = append(out[p][:i], out[p][i+1:]...)
+			} else {
+				out[p][i] = nat.PortBinding{
+					HostIP:   iface,
+					HostPort: alloc.HostPort,
+				}
+			}
+		}
+	}
+
+	return out
+}
+
 // Converts the server allocation mappings into a PortSet that can be understood
 // by Docker. This formatting is slightly different than "Bindings" as it should
 // return an empty struct rather than a binding.
 //
-// To accomplish this, we'll just get the values from "Bindings" and then set them
+// To accomplish this, we'll just get the values from "DockerBindings" and then set them
 // to empty structs. Because why not.
 func (a *Allocations) Exposed() nat.PortSet {
 	var out = nat.PortSet{}
 
-	for port := range a.Bindings() {
+	for port := range a.DockerBindings() {
 		out[port] = struct{}{}
 	}
 

environment/docker/container.go

@@ -164,7 +164,7 @@ func (e *Environment) Create() error {
 	tmpfsSize := strconv.Itoa(int(config.Get().Docker.TmpfsSize))
 
 	hostConf := &container.HostConfig{
-		PortBindings: a.Bindings(),
+		PortBindings: a.DockerBindings(),
 
 		// Configure the mounts for this container. First mount the server data directory
 		// into the container as a r/w bind.

server/server.go

@@ -6,6 +6,7 @@ import (
 	"github.com/apex/log"
 	"github.com/pkg/errors"
 	"github.com/pterodactyl/wings/api"
+	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
 	"github.com/pterodactyl/wings/environment/docker"
 	"github.com/pterodactyl/wings/events"
@@ -74,11 +75,18 @@ func (s *Server) Id() string {
 func (s *Server) GetEnvironmentVariables() []string {
 	zone, _ := time.Now().In(time.Local).Zone()
 
+	var ip = s.Config().Allocations.DefaultMapping.Ip
+	// Convert 127.0.0.1 to the pterodactyl0 network interface if the environment is Docker
+	// so that the server operates as expected.
+	if s.Environment.Type() == "docker" && ip == "127.0.0.1" {
+		ip = config.Get().Docker.Network.Interface
+	}
+
 	var out = []string{
 		fmt.Sprintf("TZ=%s", zone),
 		fmt.Sprintf("STARTUP=%s", s.Config().Invocation),
 		fmt.Sprintf("SERVER_MEMORY=%d", s.MemoryLimit()),
-		fmt.Sprintf("SERVER_IP=%s", s.Config().Allocations.DefaultMapping.Ip),
+		fmt.Sprintf("SERVER_IP=%s", ip),
 		fmt.Sprintf("SERVER_PORT=%d", s.Config().Allocations.DefaultMapping.Port),
 	}