// SPDX-License-Identifier: GPL-2.0-only
/*
 * vsock test utilities
 *
 * Copyright (C) 2017 Red Hat, Inc.
 *
 * Author: Stefan Hajnoczi <stefanha@redhat.com>
 */

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <assert.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/sockios.h>

#include "timeout.h"
#include "control.h"
#include "util.h"

#define KALLSYMS_PATH           "/proc/kallsyms"
#define KALLSYMS_LINE_LEN       512

/* Install signal handlers */
void init_signals(void)
{
        struct sigaction act = {
                .sa_handler = sigalrm,
        };

        sigaction(SIGALRM, &act, NULL);
        signal(SIGPIPE, SIG_IGN);
}

static unsigned int parse_uint(const char *str, const char *err_str)
{
        char *endptr = NULL;
        unsigned long n;

        errno = 0;
        n = strtoul(str, &endptr, 10);
        if (errno || *endptr != '\0') {
                fprintf(stderr, "malformed %s \"%s\"\n", err_str, str);
                exit(EXIT_FAILURE);
        }
        return n;
}

/* Parse a CID in string representation */
unsigned int parse_cid(const char *str)
{
        return parse_uint(str, "CID");
}

/* Parse a port in string representation */
unsigned int parse_port(const char *str)
{
        return parse_uint(str, "port");
}

/* Wait for the remote to close the connection */
void vsock_wait_remote_close(int fd)
{
        struct epoll_event ev;
        int epollfd, nfds;

        epollfd = epoll_create1(0);
        if (epollfd == -1) {
                perror("epoll_create1");
                exit(EXIT_FAILURE);
        }

        ev.events = EPOLLRDHUP | EPOLLHUP;
        ev.data.fd = fd;
        if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
                perror("epoll_ctl");
                exit(EXIT_FAILURE);
        }

        nfds = epoll_wait(epollfd, &ev, 1, TIMEOUT * 1000);
        if (nfds == -1) {
                perror("epoll_wait");
                exit(EXIT_FAILURE);
        }

        if (nfds == 0) {
                fprintf(stderr, "epoll_wait timed out\n");
                exit(EXIT_FAILURE);
        }

        assert(nfds == 1);
        assert(ev.events & (EPOLLRDHUP | EPOLLHUP));
        assert(ev.data.fd == fd);

        close(epollfd);
}

/* Wait until ioctl gives an expected int value.
 * Return false if the op is not supported.
 */
bool vsock_ioctl_int(int fd, unsigned long op, int expected)
{
        int actual, ret;
        char name[32];

        snprintf(name, sizeof(name), "ioctl(%lu)", op);

        timeout_begin(TIMEOUT);
        do {
                ret = ioctl(fd, op, &actual);
                if (ret < 0) {
                        if (errno == EOPNOTSUPP || errno == ENOTTY)
                                break;

                        perror(name);
                        exit(EXIT_FAILURE);
                }
                timeout_check(name);
        } while (actual != expected);
        timeout_end();

        return ret >= 0;
}

/* Wait until transport reports no data left to be sent.
 * Return false if transport does not implement the unsent_bytes() callback.
 */
bool vsock_wait_sent(int fd)
{
        return vsock_ioctl_int(fd, SIOCOUTQ, 0);
}

/* Create socket <type>, bind to <cid, port>.
 * Return the file descriptor, or -1 on error.
 */
int vsock_bind_try(unsigned int cid, unsigned int port, int type)
{
        struct sockaddr_vm sa = {
                .svm_family = AF_VSOCK,
                .svm_cid = cid,
                .svm_port = port,
        };
        int fd, saved_errno;

        fd = socket(AF_VSOCK, type, 0);
        if (fd < 0) {
                perror("socket");
                exit(EXIT_FAILURE);
        }

        if (bind(fd, (struct sockaddr *)&sa, sizeof(sa))) {
                saved_errno = errno;
                close(fd);
                errno = saved_errno;
                fd = -1;
        }

        return fd;
}

/* Create socket <type>, bind to <cid, port> and return the file descriptor. */
int vsock_bind(unsigned int cid, unsigned int port, int type)
{
        int fd;

        fd = vsock_bind_try(cid, port, type);
        if (fd < 0) {
                perror("bind");
                exit(EXIT_FAILURE);
        }

        return fd;
}

int vsock_connect_fd(int fd, unsigned int cid, unsigned int port)
{
        struct sockaddr_vm sa = {
                .svm_family = AF_VSOCK,
                .svm_cid = cid,
                .svm_port = port,
        };
        int ret;

        timeout_begin(TIMEOUT);
        do {
                ret = connect(fd, (struct sockaddr *)&sa, sizeof(sa));
                timeout_check("connect");
        } while (ret < 0 && errno == EINTR);
        timeout_end();

        return ret;
}

/* Bind to <bind_port>, connect to <cid, port> and return the file descriptor. */
int vsock_bind_connect(unsigned int cid, unsigned int port, unsigned int bind_port, int type)
{
        int client_fd;

        client_fd = vsock_bind(VMADDR_CID_ANY, bind_port, type);

        if (vsock_connect_fd(client_fd, cid, port)) {
                perror("connect");
                exit(EXIT_FAILURE);
        }

        return client_fd;
}

/* Connect to <cid, port> and return the file descriptor. */
int vsock_connect(unsigned int cid, unsigned int port, int type)
{
        int fd;

        control_expectln("LISTENING");

        fd = socket(AF_VSOCK, type, 0);
        if (fd < 0) {
                perror("socket");
                exit(EXIT_FAILURE);
        }

        if (vsock_connect_fd(fd, cid, port)) {
                int old_errno = errno;

                close(fd);
                fd = -1;
                errno = old_errno;
        }

        return fd;
}

int vsock_stream_connect(unsigned int cid, unsigned int port)
{
        return vsock_connect(cid, port, SOCK_STREAM);
}

int vsock_seqpacket_connect(unsigned int cid, unsigned int port)
{
        return vsock_connect(cid, port, SOCK_SEQPACKET);
}

/* Listen on <cid, port> and return the file descriptor. */
static int vsock_listen(unsigned int cid, unsigned int port, int type)
{
        int fd;

        fd = vsock_bind(cid, port, type);

        if (listen(fd, 1) < 0) {
                perror("listen");
                exit(EXIT_FAILURE);
        }

        return fd;
}

/* Listen on <cid, port> and return the first incoming connection.  The remote
 * address is stored to clientaddrp.  clientaddrp may be NULL.
 */
int vsock_accept(unsigned int cid, unsigned int port,
                 struct sockaddr_vm *clientaddrp, int type)
{
        union {
                struct sockaddr sa;
                struct sockaddr_vm svm;
        } clientaddr;
        socklen_t clientaddr_len = sizeof(clientaddr.svm);
        int fd, client_fd, old_errno;

        fd = vsock_listen(cid, port, type);

        control_writeln("LISTENING");

        timeout_begin(TIMEOUT);
        do {
                client_fd = accept(fd, &clientaddr.sa, &clientaddr_len);
                timeout_check("accept");
        } while (client_fd < 0 && errno == EINTR);
        timeout_end();

        old_errno = errno;
        close(fd);
        errno = old_errno;

        if (client_fd < 0)
                return client_fd;

        if (clientaddr_len != sizeof(clientaddr.svm)) {
                fprintf(stderr, "unexpected addrlen from accept(2), %zu\n",
                        (size_t)clientaddr_len);
                exit(EXIT_FAILURE);
        }
        if (clientaddr.sa.sa_family != AF_VSOCK) {
                fprintf(stderr, "expected AF_VSOCK from accept(2), got %d\n",
                        clientaddr.sa.sa_family);
                exit(EXIT_FAILURE);
        }

        if (clientaddrp)
                *clientaddrp = clientaddr.svm;
        return client_fd;
}

int vsock_stream_accept(unsigned int cid, unsigned int port,
                        struct sockaddr_vm *clientaddrp)
{
        return vsock_accept(cid, port, clientaddrp, SOCK_STREAM);
}

int vsock_stream_listen(unsigned int cid, unsigned int port)
{
        return vsock_listen(cid, port, SOCK_STREAM);
}

int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
                           struct sockaddr_vm *clientaddrp)
{
        return vsock_accept(cid, port, clientaddrp, SOCK_SEQPACKET);
}

/* Transmit bytes from a buffer and check the return value.
 *
 * expected_ret:
 *  <0 Negative errno (for testing errors)
 *   0 End-of-file
 *  >0 Success (bytes successfully written)
 */
void send_buf(int fd, const void *buf, size_t len, int flags,
              ssize_t expected_ret)
{
        ssize_t nwritten = 0;
        ssize_t ret;

        timeout_begin(TIMEOUT);
        do {
                ret = send(fd, buf + nwritten, len - nwritten, flags);
                timeout_check("send");

                if (ret < 0 && errno == EINTR)
                        continue;
                if (ret <= 0)
                        break;

                nwritten += ret;
        } while (nwritten < len);
        timeout_end();

        if (expected_ret < 0) {
                if (ret != -1) {
                        fprintf(stderr, "bogus send(2) return value %zd (expected %zd)\n",
                                ret, expected_ret);
                        exit(EXIT_FAILURE);
                }
                if (errno != -expected_ret) {
                        perror("send");
                        exit(EXIT_FAILURE);
                }
                return;
        }

        if (ret < 0) {
                perror("send");
                exit(EXIT_FAILURE);
        }

        if (nwritten != expected_ret) {
                if (ret == 0)
                        fprintf(stderr, "unexpected EOF while sending bytes\n");

                fprintf(stderr, "bogus send(2) bytes written %zd (expected %zd)\n",
                        nwritten, expected_ret);
                exit(EXIT_FAILURE);
        }
}

/* Receive bytes in a buffer and check the return value.
 *
 * expected_ret:
 *  <0 Negative errno (for testing errors)
 *   0 End-of-file
 *  >0 Success (bytes successfully read)
 */
void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret)
{
        ssize_t nread = 0;
        ssize_t ret;

        timeout_begin(TIMEOUT);
        do {
                ret = recv(fd, buf + nread, len - nread, flags);
                timeout_check("recv");

                if (ret < 0 && errno == EINTR)
                        continue;
                if (ret <= 0)
                        break;

                nread += ret;
        } while (nread < len);
        timeout_end();

        if (expected_ret < 0) {
                if (ret != -1) {
                        fprintf(stderr, "bogus recv(2) return value %zd (expected %zd)\n",
                                ret, expected_ret);
                        exit(EXIT_FAILURE);
                }
                if (errno != -expected_ret) {
                        perror("recv");
                        exit(EXIT_FAILURE);
                }
                return;
        }

        if (ret < 0) {
                perror("recv");
                exit(EXIT_FAILURE);
        }

        if (nread != expected_ret) {
                if (ret == 0)
                        fprintf(stderr, "unexpected EOF while receiving bytes\n");

                fprintf(stderr, "bogus recv(2) bytes read %zd (expected %zd)\n",
                        nread, expected_ret);
                exit(EXIT_FAILURE);
        }
}

/* Transmit one byte and check the return value.
 *
 * expected_ret:
 *  <0 Negative errno (for testing errors)
 *   0 End-of-file
 *   1 Success
 */
void send_byte(int fd, int expected_ret, int flags)
{
        static const uint8_t byte = 'A';

        send_buf(fd, &byte, sizeof(byte), flags, expected_ret);
}

/* Receive one byte and check the return value.
 *
 * expected_ret:
 *  <0 Negative errno (for testing errors)
 *   0 End-of-file
 *   1 Success
 */
void recv_byte(int fd, int expected_ret, int flags)
{
        uint8_t byte;

        recv_buf(fd, &byte, sizeof(byte), flags, expected_ret);

        if (byte != 'A') {
                fprintf(stderr, "unexpected byte read 0x%02x\n", byte);
                exit(EXIT_FAILURE);
        }
}

/* Run test cases.  The program terminates if a failure occurs. */
void run_tests(const struct test_case *test_cases,
               const struct test_opts *opts)
{
        int i;

        for (i = 0; test_cases[i].name; i++) {
                void (*run)(const struct test_opts *opts);
                char *line;

                printf("%d - %s...", i, test_cases[i].name);
                fflush(stdout);

                /* Full barrier before executing the next test.  This
                 * ensures that client and server are executing the
                 * same test case.  In particular, it means whoever is
                 * faster will not see the peer still executing the
                 * last test.  This is important because port numbers
                 * can be used by multiple test cases.
                 */
                if (test_cases[i].skip)
                        control_writeln("SKIP");
                else
                        control_writeln("NEXT");

                line = control_readln();
                if (control_cmpln(line, "SKIP", false) || test_cases[i].skip) {

                        printf("skipped\n");

                        free(line);
                        continue;
                }

                control_cmpln(line, "NEXT", true);
                free(line);

                if (opts->mode == TEST_MODE_CLIENT)
                        run = test_cases[i].run_client;
                else
                        run = test_cases[i].run_server;

                if (run)
                        run(opts);

                printf("ok\n");
        }

        printf("All tests have been executed. Waiting other peer...");
        fflush(stdout);

        /*
         * Final full barrier, to ensure that all tests have been run and
         * that even the last one has been successful on both sides.
         */
        control_writeln("COMPLETED");
        control_expectln("COMPLETED");

        printf("ok\n");
}

void list_tests(const struct test_case *test_cases)
{
        int i;

        printf("ID\tTest name\n");

        for (i = 0; test_cases[i].name; i++)
                printf("%d\t%s\n", i, test_cases[i].name);

        exit(EXIT_FAILURE);
}

static unsigned long parse_test_id(const char *test_id_str, size_t test_cases_len)
{
        unsigned long test_id;
        char *endptr = NULL;

        errno = 0;
        test_id = strtoul(test_id_str, &endptr, 10);
        if (errno || *endptr != '\0') {
                fprintf(stderr, "malformed test ID \"%s\"\n", test_id_str);
                exit(EXIT_FAILURE);
        }

        if (test_id >= test_cases_len) {
                fprintf(stderr, "test ID (%lu) larger than the max allowed (%lu)\n",
                        test_id, test_cases_len - 1);
                exit(EXIT_FAILURE);
        }

        return test_id;
}

void skip_test(struct test_case *test_cases, size_t test_cases_len,
               const char *test_id_str)
{
        unsigned long test_id = parse_test_id(test_id_str, test_cases_len);
        test_cases[test_id].skip = true;
}

void pick_test(struct test_case *test_cases, size_t test_cases_len,
               const char *test_id_str)
{
        static bool skip_all = true;
        unsigned long test_id;

        if (skip_all) {
                unsigned long i;

                for (i = 0; i < test_cases_len; ++i)
                        test_cases[i].skip = true;

                skip_all = false;
        }

        test_id = parse_test_id(test_id_str, test_cases_len);
        test_cases[test_id].skip = false;
}

unsigned long hash_djb2(const void *data, size_t len)
{
        unsigned long hash = 5381;
        int i = 0;

        while (i < len) {
                hash = ((hash << 5) + hash) + ((unsigned char *)data)[i];
                i++;
        }

        return hash;
}

size_t iovec_bytes(const struct iovec *iov, size_t iovnum)
{
        size_t bytes;
        int i;

        for (bytes = 0, i = 0; i < iovnum; i++)
                bytes += iov[i].iov_len;

        return bytes;
}

unsigned long iovec_hash_djb2(const struct iovec *iov, size_t iovnum)
{
        unsigned long hash;
        size_t iov_bytes;
        size_t offs;
        void *tmp;
        int i;

        iov_bytes = iovec_bytes(iov, iovnum);

        tmp = malloc(iov_bytes);
        if (!tmp) {
                perror("malloc");
                exit(EXIT_FAILURE);
        }

        for (offs = 0, i = 0; i < iovnum; i++) {
                memcpy(tmp + offs, iov[i].iov_base, iov[i].iov_len);
                offs += iov[i].iov_len;
        }

        hash = hash_djb2(tmp, iov_bytes);
        free(tmp);

        return hash;
}

/* Allocates and returns new 'struct iovec *' according pattern
 * in the 'test_iovec'. For each element in the 'test_iovec' it
 * allocates new element in the resulting 'iovec'. 'iov_len'
 * of the new element is copied from 'test_iovec'. 'iov_base' is
 * allocated depending on the 'iov_base' of 'test_iovec':
 *
 * 'iov_base' == NULL -> valid buf: mmap('iov_len').
 *
 * 'iov_base' == MAP_FAILED -> invalid buf:
 *               mmap('iov_len'), then munmap('iov_len').
 *               'iov_base' still contains result of
 *               mmap().
 *
 * 'iov_base' == number -> unaligned valid buf:
 *               mmap('iov_len') + number.
 *
 * 'iovnum' is number of elements in 'test_iovec'.
 *
 * Returns new 'iovec' or calls 'exit()' on error.
 */
struct iovec *alloc_test_iovec(const struct iovec *test_iovec, int iovnum)
{
        struct iovec *iovec;
        int i;

        iovec = malloc(sizeof(*iovec) * iovnum);
        if (!iovec) {
                perror("malloc");
                exit(EXIT_FAILURE);
        }

        for (i = 0; i < iovnum; i++) {
                iovec[i].iov_len = test_iovec[i].iov_len;

                iovec[i].iov_base = mmap(NULL, iovec[i].iov_len,
                                         PROT_READ | PROT_WRITE,
                                         MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE,
                                         -1, 0);
                if (iovec[i].iov_base == MAP_FAILED) {
                        perror("mmap");
                        exit(EXIT_FAILURE);
                }

                if (test_iovec[i].iov_base != MAP_FAILED)
                        iovec[i].iov_base += (uintptr_t)test_iovec[i].iov_base;
        }

        /* Unmap "invalid" elements. */
        for (i = 0; i < iovnum; i++) {
                if (test_iovec[i].iov_base == MAP_FAILED) {
                        if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
                                perror("munmap");
                                exit(EXIT_FAILURE);
                        }
                }
        }

        for (i = 0; i < iovnum; i++) {
                int j;

                if (test_iovec[i].iov_base == MAP_FAILED)
                        continue;

                for (j = 0; j < iovec[i].iov_len; j++)
                        ((uint8_t *)iovec[i].iov_base)[j] = rand() & 0xff;
        }

        return iovec;
}

/* Frees 'iovec *', previously allocated by 'alloc_test_iovec()'.
 * On error calls 'exit()'.
 */
void free_test_iovec(const struct iovec *test_iovec,
                     struct iovec *iovec, int iovnum)
{
        int i;

        for (i = 0; i < iovnum; i++) {
                if (test_iovec[i].iov_base != MAP_FAILED) {
                        if (test_iovec[i].iov_base)
                                iovec[i].iov_base -= (uintptr_t)test_iovec[i].iov_base;

                        if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
                                perror("munmap");
                                exit(EXIT_FAILURE);
                        }
                }
        }

        free(iovec);
}

/* Set "unsigned long long" socket option and check that it's indeed set */
void setsockopt_ull_check(int fd, int level, int optname,
                          unsigned long long val, char const *errmsg)
{
        unsigned long long chkval;
        socklen_t chklen;
        int err;

        err = setsockopt(fd, level, optname, &val, sizeof(val));
        if (err) {
                fprintf(stderr, "setsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

        chkval = ~val; /* just make storage != val */
        chklen = sizeof(chkval);

        err = getsockopt(fd, level, optname, &chkval, &chklen);
        if (err) {
                fprintf(stderr, "getsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

        if (chklen != sizeof(chkval)) {
                fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
                        chklen);
                goto fail;
        }

        if (chkval != val) {
                fprintf(stderr, "value mismatch: set %llu got %llu\n", val,
                        chkval);
                goto fail;
        }
        return;
fail:
        fprintf(stderr, "%s  val %llu\n", errmsg, val);
        exit(EXIT_FAILURE);
}

/* Set "int" socket option and check that it's indeed set */
void setsockopt_int_check(int fd, int level, int optname, int val,
                          char const *errmsg)
{
        int chkval;
        socklen_t chklen;
        int err;

        err = setsockopt(fd, level, optname, &val, sizeof(val));
        if (err) {
                fprintf(stderr, "setsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

        chkval = ~val; /* just make storage != val */
        chklen = sizeof(chkval);

        err = getsockopt(fd, level, optname, &chkval, &chklen);
        if (err) {
                fprintf(stderr, "getsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

        if (chklen != sizeof(chkval)) {
                fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
                        chklen);
                goto fail;
        }

        if (chkval != val) {
                fprintf(stderr, "value mismatch: set %d got %d\n", val, chkval);
                goto fail;
        }
        return;
fail:
        fprintf(stderr, "%s val %d\n", errmsg, val);
        exit(EXIT_FAILURE);
}

static void mem_invert(unsigned char *mem, size_t size)
{
        size_t i;

        for (i = 0; i < size; i++)
                mem[i] = ~mem[i];
}

/* Set "timeval" socket option and check that it's indeed set */
void setsockopt_timeval_check(int fd, int level, int optname,
                              struct timeval val, char const *errmsg)
{
        struct timeval chkval;
        socklen_t chklen;
        int err;

        err = setsockopt(fd, level, optname, &val, sizeof(val));
        if (err) {
                fprintf(stderr, "setsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

         /* just make storage != val */
        chkval = val;
        mem_invert((unsigned char *)&chkval, sizeof(chkval));
        chklen = sizeof(chkval);

        err = getsockopt(fd, level, optname, &chkval, &chklen);
        if (err) {
                fprintf(stderr, "getsockopt err: %s (%d)\n",
                        strerror(errno), errno);
                goto fail;
        }

        if (chklen != sizeof(chkval)) {
                fprintf(stderr, "size mismatch: set %zu got %d\n", sizeof(val),
                        chklen);
                goto fail;
        }

        if (memcmp(&chkval, &val, sizeof(val)) != 0) {
                fprintf(stderr, "value mismatch: set %ld:%ld got %ld:%ld\n",
                        val.tv_sec, val.tv_usec, chkval.tv_sec, chkval.tv_usec);
                goto fail;
        }
        return;
fail:
        fprintf(stderr, "%s val %ld:%ld\n", errmsg, val.tv_sec, val.tv_usec);
        exit(EXIT_FAILURE);
}

void enable_so_zerocopy_check(int fd)
{
        setsockopt_int_check(fd, SOL_SOCKET, SO_ZEROCOPY, 1,
                             "setsockopt SO_ZEROCOPY");
}

void enable_so_linger(int fd, int timeout)
{
        struct linger optval = {
                .l_onoff = 1,
                .l_linger = timeout
        };

        if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &optval, sizeof(optval))) {
                perror("setsockopt(SO_LINGER)");
                exit(EXIT_FAILURE);
        }
}

static int __get_transports(void)
{
        char buf[KALLSYMS_LINE_LEN];
        const char *ksym;
        int ret = 0;
        FILE *f;

        f = fopen(KALLSYMS_PATH, "r");
        if (!f) {
                perror("Can't open " KALLSYMS_PATH);
                exit(EXIT_FAILURE);
        }

        while (fgets(buf, sizeof(buf), f)) {
                char *match;
                int i;

                assert(buf[strlen(buf) - 1] == '\n');

                for (i = 0; i < TRANSPORT_NUM; ++i) {
                        if (ret & BIT(i))
                                continue;

                        /* Match should be followed by '\t' or '\n'.
                         * See kallsyms.c:s_show().
                         */
                        ksym = transport_ksyms[i];
                        match = strstr(buf, ksym);
                        if (match && isspace(match[strlen(ksym)])) {
                                ret |= BIT(i);
                                break;
                        }
                }
        }

        fclose(f);
        return ret;
}

/* Return integer with TRANSPORT_* bit set for every (known) registered vsock
 * transport.
 */
int get_transports(void)
{
        static int tr = -1;

        if (tr == -1)
                tr = __get_transports();

        return tr;
}