add fault-tolerant load balancing

cmason3 · Feb 19, 2024 · b28a947 · b28a947
1 parent 86921d4
commit b28a947
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -9,10 +9,10 @@ A simple TCP and UDP based port forwarder which supports concurrent connections
          -udp [bind_host:]<listen_port>:<remote_host>:<remote_port>
          -logfile <portfwd.log>
          -config <portfwd.conf>
-         -fault-tolerant
+         -ft-tcp
 ```
 
-You can specify as many TCP and/or UDP forwarders as you wish on the command line - if you omit `bind_host` then it defaults to `127.0.0.1` - to listen on all IPs use `0.0.0.0`. If you duplicate `bind_host` and `listen_port` then it will load balance between the destinations (round-robin by default). For TCP connections instead of round-robin load balancing you can specify `-fault-tolerant`, which will keep using the same destination until it fails and will then move to the next.
+You can specify as many TCP and/or UDP forwarders as you wish on the command line - if you omit `bind_host` then it defaults to `127.0.0.1` - to listen on all IPs use `0.0.0.0`. If you duplicate `bind_host` and `listen_port` then it will load balance between the destinations (round-robin by default). For TCP connections instead of round-robin load balancing you can specify `-ft-tcp`, which will keep using the same destination until it fails and will then move to the next (fault tolerant).
 
 You also have the option of specifying multiple TCP and/or UDP forwarders (one per line) within a configuration file, e.g:
 

diff --git a/portfwd.go b/portfwd.go
@@ -98,7 +98,7 @@ func main() {
       fmt.Fprintf(os.Stderr, "               -udp [bind_host:]<listen_port>:<remote_host>:<remote_port>\n")
       fmt.Fprintf(os.Stderr, "               -logfile <portfwd.log>\n")
       fmt.Fprintf(os.Stderr, "               -config <portfwd.conf>\n")
-      fmt.Fprintf(os.Stderr, "               -fault-tolerant\n")
+      fmt.Fprintf(os.Stderr, "               -ft-tcp\n")
     }
     os.Exit(1)
   }
@@ -166,7 +166,7 @@ func parseArgs() (Args, error) {
       } else {
         return args, fmt.Errorf("invalid argument: %s", os.Args[i])
       }
-    } else if smatch(os.Args[i], "-fault-tolerant", 2) {
+    } else if smatch(os.Args[i], "-ft-tcp", 2) {
       args.mode = "FT"
 
     } else {
@@ -333,7 +333,7 @@ func udpForwarder(fwdr string, targets []string, wgf *sync.WaitGroup, args *Args
                   defer wgc.Done()
                   buf := make([]byte, bufSize)
 
-                  for { 
+                  for {
                     if n, _, err := u.dst.ReadFrom(buf); err == nil {
                       s.WriteToUDP(buf[:n], addr)
                       udpConnsMutex.Lock()
@@ -434,7 +434,7 @@ func tcpForwarder(fwdr string, targets []string, wgf *sync.WaitGroup, args *Args
             if args.mode == "FT" {
               targetMutex.Lock()
               for i, t := range targets {
-                if t == target {
+                if (t == target) && (i != (len(targets) - 1)) {
                   copy(targets[i:], targets[i + 1:])
                   targets[len(targets) - 1] = t
                   break