1434 TCP_INIT_CWND setsockopt doesn't work on passive connections.

@@ -692,23 +692,33 @@
                         /*
                          * Only allow socket with network configuration
                          * privilege to set the initial cwnd to be larger
                          * than allowed by RFC 3390.
                          */
-                        if (val <= MIN(4, MAX(2, 4380 / tcp->tcp_mss))) {
-                                tcp->tcp_init_cwnd = val;
-                                break;
-                        }
-                        if ((reterr = secpolicy_ip_config(cr, B_TRUE)) != 0) {
+                        if (val > MIN(4, MAX(2, 4380 / tcp->tcp_mss))) {
+                                if ((reterr = secpolicy_ip_config(cr, B_TRUE))
+                                    != 0) {
                                 *outlenp = 0;
                                 return (reterr);
                         }
                         if (val > tcp_max_init_cwnd) {
                                 *outlenp = 0;
                                 return (EINVAL);
                         }
+                        }
+
                         tcp->tcp_init_cwnd = val;
+
+                        /*
+                         * If the socket is connected, AND no outbound data
+                         * has been sent, reset the actual cwnd values.
+                         */
+                        if (tcp->tcp_state == TCPS_ESTABLISHED &&
+                            tcp->tcp_iss == tcp->tcp_snxt - 1) {
+                                tcp->tcp_cwnd =
+                                    MIN(tcp->tcp_rwnd, val * tcp->tcp_mss);
+                        }
                         break;
 
                 /*
                  * TCP_KEEPIDLE is in seconds but TCP_KEEPALIVE_THRESHOLD
                  * is in milliseconds. TCP_KEEPIDLE is introduced for