Add control connection keepalive arguments

configure.ac

@@ -204,6 +204,18 @@ if test "x$iperf3_cv_header_tcp_user_timeout" = "xyes"; then
     AC_DEFINE([HAVE_TCP_USER_TIMEOUT], [1], [Have TCP_USER_TIMEOUT sockopt.])
 fi
 
+# Check for TCP_KEEPIDLE sockopt (not clear where supported)
+AC_CACHE_CHECK([TCP_KEEPIDLE socket option],
+[iperf3_cv_header_tcp_keepalive],
+AC_COMPILE_IFELSE(
+  [AC_LANG_PROGRAM([[#include <netinet/tcp.h>]],
+                   [[int foo = TCP_KEEPIDLE;]])],
+  iperf3_cv_header_tcp_keepalive=yes,
+  iperf3_cv_header_tcp_keepalive=no))
+if test "x$iperf3_cv_header_tcp_keepalive" = "xyes"; then
+    AC_DEFINE([HAVE_TCP_KEEPALIVE], [1], [Have TCP_KEEPIDLE sockopt.])
+fi
+
 # Check for IPv6 flowlabel support (believed to be Linux only)
 # We check for IPV6_FLOWLABEL_MGR in <linux/in6.h> even though we
 # don't use that file directly (we have our own stripped-down

src/iperf.h

@@ -184,6 +184,10 @@ struct iperf_settings
     int       idle_timeout;         /* server idle time timeout */
     unsigned int snd_timeout; /* Timeout for sending tcp messages in active mode, in us */
     struct iperf_time rcv_timeout;  /* Timeout for receiving messages in active mode, in us */
+    int       cntl_ka;              /* Use Control TCP connection Keepalive */
+    int       cntl_ka_keepidle;     /* Control TCP connection Keepalive idle time (TCP_KEEPIDLE) */
+    int       cntl_ka_interval;     /* Control TCP connection Keepalive interval between retries (TCP_KEEPINTV) */
+    int       cntl_ka_count;        /* Control TCP connection Keepalive number of retries (TCP_KEEPCNT) */
 };
 
 struct iperf_test;

src/iperf_api.c

@@ -1149,6 +1149,9 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
         {"idle-timeout", required_argument, NULL, OPT_IDLE_TIMEOUT},
         {"rcv-timeout", required_argument, NULL, OPT_RCV_TIMEOUT},
         {"snd-timeout", required_argument, NULL, OPT_SND_TIMEOUT},
+#if defined(HAVE_TCP_KEEPALIVE)
+        {"cntl-ka", optional_argument, NULL, OPT_CNTL_KA},
+#endif /* HAVE_TCP_KEEPALIVE */
         {"debug", optional_argument, NULL, 'd'},
         {"help", no_argument, NULL, 'h'},
         {NULL, 0, NULL, 0}
@@ -1162,6 +1165,9 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
     char* comma;
 #endif /* HAVE_CPU_AFFINITY */
     char* slash;
+#if defined(HAVE_TCP_KEEPALIVE)
+    char* slash2;
+#endif /* HAVE_TCP_KEEPALIVE */
     char *p, *p1;
     struct xbind_entry *xbe;
     double farg;
@@ -1530,6 +1536,39 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
                 snd_timeout_flag = 1;
 	        break;
 #endif /* HAVE_TCP_USER_TIMEOUT */
+#if defined (HAVE_TCP_KEEPALIVE)
+            case OPT_CNTL_KA:
+                test->settings->cntl_ka = 1;
+                if (optarg) {
+                    slash = strchr(optarg, '/');
+		    if (slash) {
+		        *slash = '\0';
+		        ++slash;
+                        slash2 = strchr(slash, '/');
+                        if (slash2) {
+                            *slash2 = '\0';
+		            ++slash2;
+                            if (strlen(slash2) > 0) {
+                                test->settings->cntl_ka_count = atoi(slash2);
+                            }
+                        }
+                        if (strlen(slash) > 0) {
+                            test->settings->cntl_ka_interval = atoi(slash);
+                        }
+                    }
+                    if (strlen(optarg) > 0) {
+                        test->settings->cntl_ka_keepidle = atoi(optarg);
+                    }
+                }
+                // Seems that at least in Windows WSL2, TCP keepalive retries full inteval must be
+                // smaller than the idle interval. Otherwise, the keepalive message is sent only once.
+                if (test->settings->cntl_ka_keepidle &&
+                    test->settings->cntl_ka_keepidle <= (test->settings->cntl_ka_count * test->settings->cntl_ka_interval)) {
+                        i_errno = IECNTLKA;
+                        return -1;
+                }
+                break;
+#endif /* HAVE_TCP_KEEPALIVE */
             case 'A':
 #if defined(HAVE_CPU_AFFINITY)
                 test->affinity = strtol(optarg, &endptr, 0);
@@ -3016,6 +3055,10 @@ iperf_defaults(struct iperf_test *testp)
     testp->settings->rcv_timeout.secs = DEFAULT_NO_MSG_RCVD_TIMEOUT / SEC_TO_mS;
     testp->settings->rcv_timeout.usecs = (DEFAULT_NO_MSG_RCVD_TIMEOUT % SEC_TO_mS) * mS_TO_US;
     testp->zerocopy = 0;
+    testp->settings->cntl_ka = 0;
+    testp->settings->cntl_ka_keepidle = 0;
+    testp->settings->cntl_ka_interval = 0;
+    testp->settings->cntl_ka_count = 0;
 
     memset(testp->cookie, 0, COOKIE_SIZE);
 
@@ -5214,3 +5257,82 @@ iflush(struct iperf_test *test)
 
     return rc2;
 }
+
+#if defined (HAVE_TCP_KEEPALIVE)
+// Set Control Connection TCP Keepalive (especially useful for long UDP test sessions)
+int
+iperf_set_control_keepalive(struct iperf_test *test)
+{
+    int opt, kaidle, kainterval, kacount;
+    socklen_t len;
+
+    if (test->settings->cntl_ka) {
+        // Set keepalive using system defaults
+        opt = 1;
+        if (setsockopt(test->ctrl_sck, SOL_SOCKET, SO_KEEPALIVE, (char *) &opt, sizeof(opt))) {
+            i_errno = IESETCNTLKA;
+            return -1;
+        }
+
+        // Get default values when not specified
+        if ((kaidle = test->settings->cntl_ka_keepidle) == 0) {
+            len = sizeof(kaidle);
+            if (getsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPIDLE, (char *) &kaidle, &len)) {
+                i_errno = IESETCNTLKAINTERVAL;
+                return -1;
+            }
+        }
+        if ((kainterval = test->settings->cntl_ka_interval) == 0) {
+            len = sizeof(kainterval);
+            if (getsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPINTVL, (char *) &kainterval, &len)) {
+                i_errno = IESETCNTLKAINTERVAL;
+                return -1;
+            }
+        }
+        if ((kacount = test->settings->cntl_ka_count) == 0) {
+            len = sizeof(kacount);
+            if (getsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPCNT, (char *) &kacount, &len)) {
+                i_errno = IESETCNTLKACOUNT;
+                return -1;
+            }
+        }
+
+        // Seems that at least in Windows WSL2, TCP keepalive retries full inteval must be
+        // smaller than the idle interval. Otherwise, the keepalive message is sent only once.
+        if (test->settings->cntl_ka_keepidle) {
+            if (test->settings->cntl_ka_keepidle <= (kainterval * kacount)) {
+                iperf_err(test, "Keepalive Idle time (%d) should be greater than Retries-interval (%d) times Retries-count (%d)", kaidle, kainterval, kacount);
+                i_errno = IECNTLKA;
+                return -1;
+            }
+        }
+
+        // Set keep alive values when specified
+        if ((opt = test->settings->cntl_ka_keepidle)) {
+            if (setsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPIDLE, (char *) &opt, sizeof(opt))) {
+                i_errno = IESETCNTLKAKEEPIDLE;
+                return -1;
+            }
+        }
+        if ((opt = test->settings->cntl_ka_interval)) {
+            if (setsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPINTVL, (char *) &opt, sizeof(opt))) {
+                i_errno = IESETCNTLKAINTERVAL;
+                return -1;
+            }
+        }
+        if ((opt = test->settings->cntl_ka_count)) {
+            if (setsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_KEEPCNT, (char *) &opt, sizeof(opt))) {
+                i_errno = IESETCNTLKACOUNT;
+                return -1;
+            }
+        }
+
+        if (test->verbose) {
+            printf("Control connection TCP Keepalive TCP_KEEPIDLE/TCP_KEEPINTVL/TCP_KEEPCNT are set to %d/%d/%d\n",
+                   kaidle, kainterval, kacount);
+        }
+    }
+
+    return 0;
+}
+#endif //HAVE_TCP_KEEPALIVE

src/iperf_api.h

@@ -101,6 +101,7 @@ typedef atomic_uint_fast64_t atomic_iperf_size_t;
 #define OPT_JSON_STREAM 28
 #define OPT_SND_TIMEOUT 29
 #define OPT_USE_PKCS1_PADDING 30
+#define OPT_CNTL_KA 31
 
 /* states */
 #define TEST_START 1
@@ -309,6 +310,14 @@ void      iperf_free_stream(struct iperf_stream * sp);
  */
 int       iperf_common_sockopts(struct iperf_test *, int s);
 
+#if defined (HAVE_TCP_KEEPALIVE)
+/**
+ * iperf_set_control_keepalive -- set control connection TCP keepalive
+ *
+ */
+int       iperf_set_control_keepalive(struct iperf_test *test);
+#endif //HAVE_TCP_KEEPALIVE
+
 int has_tcpinfo(void);
 int has_tcpinfo_retransmits(void);
 void save_tcpinfo(struct iperf_stream *sp, struct iperf_interval_results *irp);
@@ -420,6 +429,7 @@ enum {
     IESNDTIMEOUT = 33,      // Illegal message send timeout
     IEUDPFILETRANSFER = 34, // Cannot transfer file using UDP
     IESERVERAUTHUSERS = 35,   // Cannot access authorized users file
+    IECNTLKA = 36,          // Control connection Keepalive period should be larger than the full retry period (interval * count)
     /* Test errors */
     IENEWTEST = 100,        // Unable to create a new test (check perror)
     IEINITTEST = 101,       // Test initialization failed (check perror)
@@ -475,7 +485,11 @@ enum {
     IEPTHREADJOIN=152,		// Unable to join thread (check perror)
     IEPTHREADATTRINIT=153,      // Unable to initialize thread attribute (check perror)
     IEPTHREADATTRDESTROY=154,      // Unable to destroy thread attribute (check perror)
-    IEPTHREADSIGMASK=155,      // Unable to initialize sub thread signal mask (check perror)
+    IESETCNTLKA = 155,         // Unable to set socket keepalive (SO_KEEPALIVE) option
+    IESETCNTLKAKEEPIDLE = 156, // Unable to set socket keepalive TCP period (TCP_KEEPIDLE) option
+    IESETCNTLKAINTERVAL = 157, // Unable to set/get socket keepalive TCP retry interval (TCP_KEEPINTVL) option
+    IESETCNTLKACOUNT = 158,    // Unable to set/get socket keepalive TCP number of retries (TCP_KEEPCNT) option
+    IEPTHREADSIGMASK=159,      // Unable to initialize sub thread signal mask (check perror)
     /* Stream errors */
     IECREATESTREAM = 200,   // Unable to create a new stream (check herror/perror)
     IEINITSTREAM = 201,     // Unable to initialize stream (check herror/perror)

src/iperf_client_api.c

@@ -444,11 +444,17 @@ iperf_connect(struct iperf_test *test)
         return -1;
     }
 
+#if defined (HAVE_TCP_KEEPALIVE)
+        // Set Control Connection TCP Keepalive (especially useful for long UDP test sessions)
+        if (iperf_set_control_keepalive(test) < 0)
+            return -1;
+#endif //HAVE_TCP_KEEPALIVE
+
 #if defined(HAVE_TCP_USER_TIMEOUT)
     if ((opt = test->settings->snd_timeout)) {
         if (setsockopt(test->ctrl_sck, IPPROTO_TCP, TCP_USER_TIMEOUT, &opt, sizeof(opt)) < 0) {
-        i_errno = IESETUSERTIMEOUT;
-        return -1;
+            i_errno = IESETUSERTIMEOUT;
+            return -1;
         }
     }
 #endif /* HAVE_TCP_USER_TIMEOUT */

src/iperf_error.c

@@ -182,7 +182,7 @@ iperf_strerror(int int_errno)
         case IEINTERVAL:
             snprintf(errstr, len, "invalid report interval (min = %g, max = %g seconds)", MIN_INTERVAL, MAX_INTERVAL);
             break;
-    case IEBIND: /* UNUSED */
+        case IEBIND: /* UNUSED */
             snprintf(errstr, len, "--bind must be specified to use --cport");
             break;
         case IEUDPBLOCKSIZE:
@@ -464,7 +464,7 @@ iperf_strerror(int int_errno)
 	case IETOTALRATE:
 	    snprintf(errstr, len, "total required bandwidth is larger than server limit");
             break;
-    case IESKEWTHRESHOLD:
+        case IESKEWTHRESHOLD:
 	    snprintf(errstr, len, "skew threshold must be a positive number");
             break;
 	case IEIDLETIMEOUT:
@@ -473,16 +473,16 @@ iperf_strerror(int int_errno)
 	case IEBINDDEV:
 	    snprintf(errstr, len, "Unable to bind-to-device (check perror, maybe permissions?)");
             break;
-    case IEBINDDEVNOSUPPORT:
+        case IEBINDDEVNOSUPPORT:
 	    snprintf(errstr, len, "`<ip>%%<dev>` is not supported as system does not support bind to device");
             break;
-    case IEHOSTDEV:
+        case IEHOSTDEV:
 	    snprintf(errstr, len, "host device name (ip%%<dev>) is supported (and required) only for IPv6 link-local address");
             break;        
 	case IENOMSG:
 	    snprintf(errstr, len, "idle timeout for receiving data");
             break;
-    case IESETDONTFRAGMENT:
+        case IESETDONTFRAGMENT:
 	    snprintf(errstr, len, "unable to set IP Do-Not-Fragment flag");
             break;
         case IESETUSERTIMEOUT:
@@ -510,6 +510,24 @@ iperf_strerror(int int_errno)
 	    break;
 	case IEPTHREADATTRDESTROY:
             snprintf(errstr, len, "unable to destroy thread attributes");
+        case IECNTLKA:
+            snprintf(errstr, len, "control connection Keepalive period should be larger than the full retry period (interval * count)");
+            perr = 1;
+            break;
+        case IESETCNTLKA:
+            snprintf(errstr, len, "unable to set socket keepalive (SO_KEEPALIVE) option");
+            perr = 1;
+            break;
+        case IESETCNTLKAKEEPIDLE:
+            snprintf(errstr, len, "unable to set socket keepalive TCP period (TCP_KEEPIDLE) option");
+            perr = 1;
+            break;
+        case IESETCNTLKAINTERVAL:
+            snprintf(errstr, len, "unable to set/get socket keepalive TCP retry interval (TCP_KEEPINTVL) option");
+            perr = 1;
+            break;
+        case IESETCNTLKACOUNT:
+            snprintf(errstr, len, "unable to set/get socket keepalive TCP number of retries (TCP_KEEPCNT) option");
             perr = 1;
             break;
 	default:

src/iperf_locale.c

@@ -128,6 +128,10 @@ const char usage_longstr[] = "Usage: iperf3 [-s|-c host] [options]\n"
                            "  --snd-timeout #           timeout for unacknowledged TCP data\n"
                            "                            (in ms, default is system settings)\n"
 #endif /* HAVE_TCP_USER_TIMEOUT */
+#if defined(HAVE_TCP_KEEPALIVE)
+                           "  --cntl-ka[=#/#/#]         use control connection TCP keepalive - KEEPIDLE/KEEPINTV/KEEPCNT\n"
+                           "                            each value is optional with system settings default\n"
+#endif //HAVE_TCP_KEEPALIVE
                            "  -d, --debug[=#]           emit debugging output\n"
                            "                            (optional optional \"=\" and debug level: 1-4. Default is 4 - all messages)\n"
                            "  -v, --version             show version information and quit\n"

src/iperf_server_api.c

@@ -184,6 +184,12 @@ iperf_accept(struct iperf_test *test)
         }
 #endif /* HAVE_TCP_USER_TIMEOUT */
 
+#if defined (HAVE_TCP_KEEPALIVE)
+        // Set Control Connection TCP Keepalive (especially useful for long UDP test sessions)
+        if (iperf_set_control_keepalive(test) < 0)
+            return -1;
+#endif //HAVE_TCP_KEEPALIVE
+
         if (Nread(test->ctrl_sck, test->cookie, COOKIE_SIZE, Ptcp) != COOKIE_SIZE) {
             /*
              * Note this error covers both the case of a system error