2  *  Copyright 2024-2025 The OpenSSL Project Authors. All Rights Reserved.
11  * @file quic-hq-interop.c
15  * interoperability with hq-interop servers. It handles connection setup,
20  * and uses non-blocking mode for QUIC operations.
30  * quic-hq-interop <host> <port> <reqfile>
31  * host - The hostname of the server to contact
32  * port - The port that the server is listening on
33  * reqfile - a text file containing a space separated list of paths to fetch
37  * SSLKEYLOGFILE - set to a file path to record keylog exchange with server
38  * SSL_SESSION_FILE - set to a file path to record ssl sessions and restore
40  * SSL_CERT_FILE - The ca file to use when validating a server
41  * SSL_CIPHER_SUITES - The list of cipher suites to use (see openssl-ciphers)
93  * @note The function uses OpenSSL's socket-related functions (e.g., BIO_socket,
103     int sock = -1;  in create_socket_bio()
121          * Create a UDP socket. We could equally use non-OpenSSL calls such  in create_socket_bio()
128         if (sock == -1)  in create_socket_bio()
134             sock = -1;  in create_socket_bio()
145             sock = -1;  in create_socket_bio()
152     if (sock != -1) {  in create_socket_bio()
163     /* If sock is -1 then we've been unable to connect to the server */  in create_socket_bio()
164     if (sock == -1)  in create_socket_bio()
201  * until the timeout specified by OpenSSL is reached. In a real application,
207  * mechanisms like poll or epoll for handling multiple file descriptors.
242      * poll/epoll or similar functions  in wait_for_activity()
250      * a GUI every 100ms. One way to do that would be to use the timeout in  in wait_for_activity()
252      * than 100ms then use 100ms instead. Then, when select returns, you  in wait_for_activity()
254      * because of the timeout. If the 100ms GUI timeout has expired but the  in wait_for_activity()
255      * tvp timeout has not then go and update the GUI and then restart the  in wait_for_activity()
273  *         - 1: Temporary failure, the operation should be retried.
274  *         - 0: EOF, indicating the connection has been closed.
275  *         - -1: A fatal error occurred or the connection has been reset.
297         return -1;  in handle_io_failure()
302          * stream reset - or some failure occurred on the underlying  in handle_io_failure()
330         return -1;  in handle_io_failure()
333         return -1;  in handle_io_failure()
478  * @brief Counter for the number of poll items.
512  * @brief Builds and processes a set of SSL poll requests.
514  * This function creates a new set of SSL poll requests based on the current
515  * request array. It allocates and manages memory for poll lists, BIO output
522  * @return The number of poll requests successfully built, or 0 on error.
536      * Free any previous poll list  in build_request_set()
558      * note req_idx may start at a non-zero value if  in build_request_set()
563         /* Up our poll count and set our poll_list index */  in build_request_set()
565         poll_idx = poll_count - 1;  in build_request_set()
640             poll_count--;  in build_request_set()
645          * Create a poll descriptor for this stream  in build_request_set()
691  * performs host verification, configures ALPN, and establishes a non-blocking
704     unsigned char alpn[] = {10, 'h', 'q', '-', 'i', 'n', 't', 'e', 'r', 'o', 'p'};  in setup_connection()
835  * @brief Entry point for the QUIC hq-interop client demo application.
838  * requests for files specified in the command-line arguments, and saves
842  * @param argc The number of command-line arguments.
843  * @param argv The array of command-line arguments. The expected format is
848  *       - Parses command-line arguments.
849  *       - Reads the list of requests from the specified file.
850  *       - Sets up the SSL context and configures certificate verification.
851  *       - Optionally enables key logging and session caching.
852  *       - Establishes a non-blocking QUIC connection to the server.
853  *       - Sends an HTTP GET request for each file and writes the response
855  *       - Gracefully shuts down the SSL connection and frees resources.
856  *       - Prints any OpenSSL error stack information on failure.
882         fprintf(stderr, "Usage: quic-hq-interop hostname port reqfile\n");  in main()
923         req_array[total_requests - 1] = req;  in main()
927     /* get a list of requests to poll */  in main()
931      * Now poll all our descriptors for events  in main()
939             fprintf(stderr, "Failed to poll\n");  in main()
943         /* Iterate over our poll array looking for ready SSL's */  in main()
947              * indicated were ready, we can go poll again  in main()
956                 result_count--;  in main()
958                 /* And clear the revents for the next poll */  in main()
974                         break; /* Retry on next poll */  in main()
978                     case -1:  in main()
1002          * If we've completed this poll set, try get another one  in main()