tcp windows大小控制

" -R n  SO_RCVBUF option
"


case 'R':                       /* SO_RCVBUF socket option */
rcvbuflen = atoi(optarg);
break;


        /* Set the socket send and receive buffer sizes (if specified).
           The receive buffer size is tied to TCP's advertised window. */

        if (rcvbuflen) {
                if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &rcvbuflen,
                               sizeof(rcvbuflen)) < 0)
                        err_sys("SO_RCVBUF setsockopt error");

                optlen = sizeof(n);
                if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &n, &optlen) < 0)
                        err_sys("SO_RCVBUF getsockopt error");
                if (n != rcvbuflen)
                        err_quit("error: requested rcvbuflen = %d, resulting SO_RCVBUF = %d", rcvbuflen, n);
                if (verbose)
                        fprintf(stderr, "SO_RCVBUF = %d
", n);
        }