OS-4647 lx fails to mount nfs share - Transport endpoint is already connected

*** 1581,1590 ****
--- 1581,1595 ----
                  case UDP_RCVHDR:
                          mutex_enter(&connp->conn_lock);
                          *i1 = udp->udp_rcvhdr ? 1 : 0;
                          mutex_exit(&connp->conn_lock);
                          return (sizeof (int));
+                 case UDP_SND_TO_CONNECTED:
+                         mutex_enter(&connp->conn_lock);
+                         *i1 = udp->udp_snd_to_conn ? 1 : 0;
+                         mutex_exit(&connp->conn_lock);
+                         return (sizeof (int));
                  }
          }
          mutex_enter(&connp->conn_lock);
          retval = conn_opt_get(&coas, level, name, ptr);
          mutex_exit(&connp->conn_lock);
*** 1716,1725 ****
--- 1721,1735 ----
                  case UDP_RCVHDR:
                          mutex_enter(&connp->conn_lock);
                          udp->udp_rcvhdr = onoff;
                          mutex_exit(&connp->conn_lock);
                          return (0);
+                 case UDP_SND_TO_CONNECTED:
+                         mutex_enter(&connp->conn_lock);
+                         udp->udp_snd_to_conn = onoff;
+                         mutex_exit(&connp->conn_lock);
+                         return (0);
                  }
                  break;
          }
          error = conn_opt_set(coa, level, name, inlen, invalp,
              checkonly, cr);
*** 5908,5917 ****
--- 5918,5928 ----
          int             error = 0;
          udp_stack_t     *us = udp->udp_us;
          ushort_t        ipversion;
          pid_t           pid = curproc->p_pid;
          ip_xmit_attr_t  *ixa;
+         boolean_t       snd_to_conn;
  
          ASSERT(DB_TYPE(mp) == M_DATA);
  
          /* All Solaris components should pass a cred for this operation. */
          ASSERT(cr != NULL);
*** 5945,5958 ****
                  if (us->us_sendto_ignerr)
                          return (0);
                  else
                          return (error);
          }
!         if (udp->udp_state == TS_DATA_XFER) {
                  UDPS_BUMP_MIB(us, udpOutErrors);
                  return (EISCONN);
          }
          error = proto_verify_ip_addr(connp->conn_family,
              (struct sockaddr *)msg->msg_name, msg->msg_namelen);
          if (error != 0) {
                  UDPS_BUMP_MIB(us, udpOutErrors);
                  return (error);
--- 5956,5980 ----
                  if (us->us_sendto_ignerr)
                          return (0);
                  else
                          return (error);
          }
! 
!         /*
!          * Check if we're allowed to send to a connection on which we've
!          * already called 'connect'. The posix spec. allows both behaviors but
!          * historically we've returned an error if already connected. The
!          * client can allow this via a sockopt.
!          */
!         mutex_enter(&connp->conn_lock);
!         snd_to_conn = (udp->udp_snd_to_conn != 0);
!         mutex_exit(&connp->conn_lock);
!         if (udp->udp_state == TS_DATA_XFER && !snd_to_conn) {
                  UDPS_BUMP_MIB(us, udpOutErrors);
                  return (EISCONN);
          }
+ 
          error = proto_verify_ip_addr(connp->conn_family,
              (struct sockaddr *)msg->msg_name, msg->msg_namelen);
          if (error != 0) {
                  UDPS_BUMP_MIB(us, udpOutErrors);
                  return (error);