Merge pull request #81 from Climax777/master

Fixes #76

Makefile

@@ -103,6 +103,7 @@ OBJS=xl2tpd.o pty.o misc.o control.o avp.o call.o network.o avpsend.o scheduler.
 SRCS=${OBJS:.o=.c} ${HDRS}
 CONTROL_SRCS=xl2tpd-control.c
 #LIBS= $(OSLIBS) # -lefence # efence for malloc checking
+LDLIBS= -lm
 EXEC=xl2tpd
 CONTROL_EXEC=xl2tpd-control
 

network.c

@@ -30,6 +30,8 @@
 #include "ipsecmast.h"
 #include "misc.h"    /* for IPADDY macro */
 
+#include <math.h>
+
 char hostname[256];
 struct sockaddr_in server, from;        /* Server and transmitter structs */
 int server_socket;              /* Server socket */
@@ -264,9 +266,9 @@ void control_xmit (void *b)
     else
     {
         /*
-           * FIXME:  How about adaptive timeouts?
+           * Adaptive timeout with exponential backoff
          */
-        tv.tv_sec = 1;
+        tv.tv_sec = 1*pow(2, buf->retries-1);
         tv.tv_usec = 0;
         schedule (tv, control_xmit, buf);
 #ifdef DEBUG_CONTROL_XMIT