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udp_proxy.go
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/
udp_proxy.go
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//go:build !no_proxies && !no_services
// +build !no_proxies,!no_services
package services
import (
"fmt"
"net"
"github.com/ansible/receptor/pkg/logger"
"github.com/ansible/receptor/pkg/netceptor"
"github.com/ansible/receptor/pkg/utils"
"github.com/ghjm/cmdline"
)
// UDPProxyServiceInbound listens on a UDP port and forwards packets to a remote Receptor service.
func UDPProxyServiceInbound(s *netceptor.Netceptor, host string, port int, node string, service string) error {
connMap := make(map[string]netceptor.PacketConner)
buffer := make([]byte, utils.NormalBufferSize)
addrStr := fmt.Sprintf("%s:%d", host, port)
udpAddr, err := net.ResolveUDPAddr("udp", addrStr)
if err != nil {
return fmt.Errorf("could not resolve address %s", addrStr)
}
uc, err := net.ListenUDP("udp", udpAddr)
if err != nil {
return fmt.Errorf("error listening on UDP: %s", err)
}
ncAddr := s.NewAddr(node, service)
go func() {
for {
n, addr, err := uc.ReadFrom(buffer)
if err != nil {
s.Logger.Error("Error reading from UDP: %s\n", err)
return
}
raddrStr := addr.String()
pc, ok := connMap[raddrStr]
if !ok {
pc, err = s.ListenPacket("")
if err != nil {
s.Logger.Error("Error listening on Receptor network: %s\n", err)
return
}
s.Logger.Debug("Received new UDP connection from %s\n", raddrStr)
connMap[raddrStr] = pc
go runNetceptorToUDPInbound(pc, uc, addr, s.NewAddr(node, service), s.Logger)
}
wn, err := pc.WriteTo(buffer[:n], ncAddr)
if err != nil {
s.Logger.Error("Error sending packet on Receptor network: %s\n", err)
continue
}
if wn != n {
s.Logger.Debug("Not all bytes written on Receptor network\n")
continue
}
}
}()
return nil
}
func runNetceptorToUDPInbound(pc netceptor.PacketConner, uc *net.UDPConn, udpAddr net.Addr, expectedAddr netceptor.Addr, logger *logger.ReceptorLogger) {
buf := make([]byte, utils.NormalBufferSize)
for {
n, addr, err := pc.ReadFrom(buf)
if err != nil {
logger.Error("Error reading from Receptor network: %s\n", err)
continue
}
if addr != expectedAddr {
logger.Debug("Received packet from unexpected source %s\n", addr)
continue
}
wn, err := uc.WriteTo(buf[:n], udpAddr)
if err != nil {
logger.Error("Error sending packet via UDP: %s\n", err)
continue
}
if wn != n {
logger.Debug("Not all bytes written via UDP\n")
continue
}
}
}
// UDPProxyServiceOutbound listens on the Receptor network and forwards packets via UDP.
func UDPProxyServiceOutbound(s *netceptor.Netceptor, service string, address string) error {
connMap := make(map[string]*net.UDPConn)
buffer := make([]byte, utils.NormalBufferSize)
udpAddr, err := net.ResolveUDPAddr("udp", address)
if err != nil {
return fmt.Errorf("could not resolve UDP address %s", address)
}
pc, err := s.ListenPacketAndAdvertise(service, map[string]string{
"type": "UDP Proxy",
"address": address,
})
if err != nil {
return fmt.Errorf("error listening on service %s: %s", service, err)
}
go func() {
for {
n, addr, err := pc.ReadFrom(buffer)
if err != nil {
s.Logger.Error("Error reading from Receptor network: %s\n", err)
return
}
raddrStr := addr.String()
uc, ok := connMap[raddrStr]
if !ok {
uc, err = net.DialUDP("udp", nil, udpAddr)
if err != nil {
s.Logger.Error("Error connecting via UDP: %s\n", err)
return
}
s.Logger.Debug("Opened new UDP connection to %s\n", raddrStr)
connMap[raddrStr] = uc
go runUDPToNetceptorOutbound(uc, pc, addr, s.Logger)
}
wn, err := uc.Write(buffer[:n])
if err != nil {
s.Logger.Error("Error writing to UDP: %s\n", err)
continue
}
if wn != n {
s.Logger.Debug("Not all bytes written to UDP\n")
continue
}
}
}()
return nil
}
func runUDPToNetceptorOutbound(uc *net.UDPConn, pc netceptor.PacketConner, addr net.Addr, logger *logger.ReceptorLogger) {
buf := make([]byte, utils.NormalBufferSize)
for {
n, err := uc.Read(buf)
if err != nil {
logger.Error("Error reading from UDP: %s\n", err)
return
}
wn, err := pc.WriteTo(buf[:n], addr)
if err != nil {
logger.Error("Error writing to the Receptor network: %s\n", err)
continue
}
if wn != n {
logger.Debug("Not all bytes written to the Netceptor network\n")
continue
}
}
}
// udpProxyInboundCfg is the cmdline configuration object for a UDP inbound proxy.
type udpProxyInboundCfg struct {
Port int `required:"true" description:"Local UDP port to bind to"`
BindAddr string `description:"Address to bind UDP listener to" default:"0.0.0.0"`
RemoteNode string `required:"true" description:"Receptor node to connect to"`
RemoteService string `required:"true" description:"Receptor service name to connect to"`
}
// Run runs the action.
func (cfg udpProxyInboundCfg) Run() error {
netceptor.MainInstance.Logger.Debug("Running UDP inbound proxy service %v\n", cfg)
return UDPProxyServiceInbound(netceptor.MainInstance, cfg.BindAddr, cfg.Port, cfg.RemoteNode, cfg.RemoteService)
}
// udpProxyOutboundCfg is the cmdline configuration object for a UDP outbound proxy.
type udpProxyOutboundCfg struct {
Service string `required:"true" description:"Receptor service name to bind to"`
Address string `required:"true" description:"Address for outbound UDP connection"`
}
// Run runs the action.
func (cfg udpProxyOutboundCfg) Run() error {
netceptor.MainInstance.Logger.Debug("Running UDP outbound proxy service %s\n", cfg)
return UDPProxyServiceOutbound(netceptor.MainInstance, cfg.Service, cfg.Address)
}
func init() {
cmdline.RegisterConfigTypeForApp("receptor-proxies",
"udp-server", "Listen for UDP and forward via Receptor", udpProxyInboundCfg{}, cmdline.Section(servicesSection))
cmdline.RegisterConfigTypeForApp("receptor-proxies",
"udp-client", "Listen on a Receptor service and forward via UDP", udpProxyOutboundCfg{}, cmdline.Section(servicesSection))
}