bio_fd_tests.c

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/*
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *   Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Tests for the FD bio
 *
 * @file src/lib/bio/test/bio_fd_tests.c
 *
 * @copyright 2026 Network RADIUS SAS (legal@networkradius.com)
 */
#include <freeradius-devel/util/test/acutest_common_init.h>
#include <freeradius-devel/util/test/acutest_helpers.h>
 
#define _BIO_PRIVATE 1
#include <freeradius-devel/bio/bio_priv.h>
#include <freeradius-devel/bio/fd.h>
#include <freeradius-devel/util/syserror.h>
 
static int      connected_count;
static int      error_count;
static int      timeout_count;
 
static void     cb_connected(fr_bio_t *bio)     { (void) bio; connected_count++; }
static void     cb_error(fr_bio_t *bio)         { (void) bio; error_count++; }
static void     cb_timeout(fr_bio_t *bio)       { (void) bio; timeout_count++; }
 
/** Open a TCP socket listening on loopback
 *
 *  The kernel completes the TCP handshake for any listening socket, and the test needs only the
 *  handshake.  The test never calls accept(), so the kernel holds the new connection in the backlog of
 *  the listening socket.
 *
 * @param[out] port     the port which the kernel picked.
 * @return
 *      - >=0 the listening socket.
 *      - <0 on error.
 */
static int loopback_listen(uint16_t *port)
{
        struct sockaddr_in      sin = {
                                        .sin_family = AF_INET,
                                        .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
                                };
        socklen_t               len = sizeof(sin);
        int                     fd;
 
        fd = socket(AF_INET, SOCK_STREAM, 0);
        if (fd < 0) return -1;
 
        if ((bind(fd, (struct sockaddr *) &sin, sizeof(sin)) < 0) ||
            (listen(fd, 5) < 0) ||
            (getsockname(fd, (struct sockaddr *) &sin, &len) < 0)) {
                close(fd);
                return -1;
        }
 
        *port = ntohs(sin.sin_port);
        return fd;
}
 
/** A deferred connect which succeeds has to call the connected callback
 *
 *  A non-blocking connect() to a listening loopback port can return EINPROGRESS.  On EINPROGRESS,
 *  fr_bio_fd_connect_full() defers the connect, and the event loop calls fr_bio_fd_el_connect() once
 *  the socket is writable.  fr_bio_fd_el_connect() then calls connect() a second time.  If the
 *  handshake has finished, the second connect() can fail with EISCONN, so fr_bio_fd_try_connect() has
 *  to treat EISCONN as success.
 *
 *  The test needs a connect which succeeds, because a connect which fails may not reach
 *  fr_bio_fd_el_connect().  kqueue can report a refused connect with EV_EOF, and event.c passes EV_EOF
 *  to the error callback, fr_bio_fd_el_error().
 */
static void test_deferred_connect_success_calls_connected_cb(void)
{
        TALLOC_CTX              *ctx = talloc_init_const("test");
        fr_bio_fd_config_t      cfg;
        fr_bio_t                *bio;
        fr_event_list_t         *el;
        fr_time_delta_t         timeout = fr_time_delta_from_sec(5);
        uint16_t                port;
        int                     listen_fd;
        int                     rcode;
 
        connected_count = 0;
        error_count = 0;
        timeout_count = 0;
 
        listen_fd = loopback_listen(&port);
        TEST_CHECK(listen_fd >= 0);
        if (listen_fd < 0) goto done;
 
        el = fr_event_list_alloc(ctx, NULL, NULL);
        TEST_CHECK(el != NULL);
        if (!el) goto done;
 
        cfg = (fr_bio_fd_config_t) {
                .type = FR_BIO_FD_CONNECTED,
                .socket_type = SOCK_STREAM,
                .transport_type = FR_BIO_FD_TRANSPORT_TCP,
                .async = true,
                .src_ipaddr = {
                        .af = AF_INET,
                        .addr.v4.s_addr = htonl(INADDR_LOOPBACK),
                        .prefix = 32,
                },
                .dst_port = port,
        };
        cfg.dst_ipaddr = cfg.src_ipaddr;
 
        bio = fr_bio_fd_alloc(ctx, &cfg, 0);
        TEST_CHECK(bio != NULL);
        if (!bio) goto done;
 
        rcode = fr_bio_fd_connect_full(bio, el, cb_connected, cb_error, &timeout, cb_timeout);
 
        /*
         *      FreeBSD completes a loopback TCP handshake inside connect(), so the connect can
         *      finish at once (rcode 1).  Linux and macOS return EINPROGRESS and defer it (rcode 0).
         */
        TEST_MSG("connect_full returned %d.  0 means deferred, 1 means connected at once, <0 means failed", rcode);
        TEST_CHECK(rcode >= 0);
        if (rcode < 0) goto done;
 
        /*
         *      Wait in the event loop until one of the three callbacks runs.  The connect timeout
         *      is a timer, so a wait always ends, and a connect which never finishes cannot hang
         *      the test.
         */
        while (!connected_count && !error_count && !timeout_count) {
                if (fr_event_corral(el, fr_time(), true) < 0) break;
                fr_event_service(el);
        }
 
        TEST_CASE("the connected callback ran");
        TEST_CHECK(connected_count == 1);
        TEST_MSG("connected_count = %d, error_count = %d, timeout_count = %d, connect_errno = %d",
                 connected_count, error_count, timeout_count, fr_bio_fd_info(bio)->connect_errno);
 
        TEST_CASE("neither the error callback nor the timeout callback ran");
        TEST_CHECK(error_count == 0);
        TEST_CHECK(timeout_count == 0);
 
        TEST_CASE("the bio is open");
        TEST_CHECK(fr_bio_fd_info(bio)->state == FR_BIO_FD_STATE_OPEN);
 
done:
        if (listen_fd >= 0) close(listen_fd);
        talloc_free(ctx);
}
 
/** Read one packet through an unconnected UDP bio bound to the wildcard address
 *
 *  The local address of a bio bound to the wildcard address does not identify the address that a
 *  packet was sent to.  fr_bio_fd_init_common() therefore installs fr_bio_fd_recvfromto4() or
 *  fr_bio_fd_recvfromto6().  Those two functions read the destination address from a control message
 *  (data which recvmsg() returns beside the packet), and copy the destination port from the port of
 *  the bio.
 *
 *  fr_bio_fd_common_datagram() also enables receive timestamps, so each packet carries two control
 *  messages.  If cbuf in fr_bio_fd_t is too small for both control messages, then the bio drops every
 *  packet.
 */
/** See if the IPv6 loopback address can be used
 *
 *  Some hosts and containers turn IPv6 off.  The bind() fails there, and errno says why.
 */
static bool ipv6_loopback_usable(void)
{
        struct sockaddr_in6     sin6 = {
                                        .sin6_family = AF_INET6,
                                        .sin6_addr = IN6ADDR_LOOPBACK_INIT,
                                };
        int                     fd;
        bool                    usable;
 
        fd = socket(AF_INET6, SOCK_DGRAM, 0);
        if (fd < 0) return false;
 
        usable = (bind(fd, (struct sockaddr *) &sin6, sizeof(sin6)) == 0);
        close(fd);
 
        return usable;
}
 
static void recvfromto_test(int af)
{
        TALLOC_CTX              *ctx = talloc_init_const("test");
        fr_bio_fd_config_t      cfg;
        fr_bio_t                *bio;
        fr_bio_fd_info_t const  *info;
        fr_bio_fd_packet_ctx_t  packet_ctx = {};
        fr_ipaddr_t             loopback;
        struct sockaddr_storage to;
        socklen_t               to_len;
        uint8_t                 buffer[16];
        ssize_t                 rcode;
        int                     fd = -1;
        struct timeval          recv_timeout = { .tv_sec = 5 };
 
        if ((af == AF_INET6) && !ipv6_loopback_usable()) {
                TEST_SKIP("the IPv6 loopback address is not available: %s", fr_syserror(errno));
                talloc_free(ctx);
                return;
        }
 
        cfg = (fr_bio_fd_config_t) {
                .type = FR_BIO_FD_UNCONNECTED,
                .socket_type = SOCK_DGRAM,
                .transport_type = FR_BIO_FD_TRANSPORT_UDP,
                .src_ipaddr = {
                        .af = af,
                        .prefix = (af == AF_INET) ? 32 : 128,
                },
        };
 
        bio = fr_bio_fd_alloc(ctx, &cfg, 0);
        TEST_CHECK(bio != NULL);
        TEST_MSG("fr_bio_fd_alloc failed: %s", fr_strerror());
        if (!bio) goto done;
 
        info = fr_bio_fd_info(bio);
        TEST_CHECK(info->socket.inet.src_port != 0);
        TEST_MSG("the bio did not learn the port which the kernel picked");
 
        /*
         *      Send one packet to the loopback address and the port of the bio.
         */
        if (af == AF_INET) {
                loopback = (fr_ipaddr_t) { .af = AF_INET, .prefix = 32, .addr.v4.s_addr = htonl(INADDR_LOOPBACK) };
        } else {
                loopback = (fr_ipaddr_t) { .af = AF_INET6, .prefix = 128, .addr.v6 = in6addr_loopback };
        }
 
        TEST_CHECK(fr_ipaddr_to_sockaddr(&to, &to_len, &loopback, info->socket.inet.src_port) == 0);
 
        fd = socket(af, SOCK_DGRAM, 0);
        TEST_CHECK(fd >= 0);
        if (fd < 0) goto done;
 
        rcode = sendto(fd, "x", 1, 0, (struct sockaddr *) &to, to_len);
        TEST_CHECK(rcode == 1);
        TEST_MSG("sendto failed: %s", fr_syserror(errno));
        if (rcode != 1) goto done;
 
        /*
         *      The socket of the bio is blocking, so fr_bio_read() waits until the packet arrives.  The
         *      receive timeout stops the test from waiting forever if the packet never arrives.
         */
        TEST_CHECK(setsockopt(info->socket.fd, SOL_SOCKET, SO_RCVTIMEO, &recv_timeout, sizeof(recv_timeout)) == 0);
 
        rcode = fr_bio_read(bio, &packet_ctx, buffer, sizeof(buffer));
 
        TEST_CASE("the packet is read, not dropped");
        TEST_CHECK(rcode == 1);
        TEST_MSG("fr_bio_read returned %zd", rcode);
        if (rcode != 1) goto done;
 
        TEST_CASE("the destination is the loopback address and the port of the bio");
        TEST_CHECK(fr_ipaddr_cmp(&packet_ctx.socket.inet.dst_ipaddr, &loopback) == 0);
        TEST_CHECK(packet_ctx.socket.inet.dst_port == info->socket.inet.src_port);
        TEST_MSG("dst_port = %u, expected %u", packet_ctx.socket.inet.dst_port, info->socket.inet.src_port);
 
done:
        if (fd >= 0) close(fd);
        talloc_free(ctx);
}
 
static void test_recvfromto4(void)
{
        recvfromto_test(AF_INET);
}
 
static void test_recvfromto6(void)
{
        recvfromto_test(AF_INET6);
}
 
TEST_LIST = {
        { "deferred_connect_success_calls_connected_cb",        test_deferred_connect_success_calls_connected_cb },
        { "recvfromto4",                                        test_recvfromto4 },
        { "recvfromto6",                                        test_recvfromto6 },
        TEST_TERMINATOR
};