// SPDX-License-Identifier: GPL-2.0
/*
 * This times how long it takes to bind to a port when the port already
 * has multiple sockets in its bhash table.
 *
 * In the setup(), we populate the port's bhash table with
 * MAX_THREADS * MAX_CONNECTIONS number of entries.
 */

#include <unistd.h>
#include <stdio.h>
#include <netdb.h>
#include <pthread.h>
#include <string.h>
#include <stdbool.h>

#define MAX_THREADS 600
#define MAX_CONNECTIONS 40

static const char *setup_addr_v6 = "::1";
static const char *setup_addr_v4 = "127.0.0.1";
static const char *setup_addr;
static const char *bind_addr;
static const char *port;
bool use_v6;
int ret;

static int fd_array[MAX_THREADS][MAX_CONNECTIONS];

static int bind_socket(int opt, const char *addr)
{
        struct addrinfo *res, hint = {};
        int sock_fd, reuse = 1, err;
        int domain = use_v6 ? AF_INET6 : AF_INET;

        sock_fd = socket(domain, SOCK_STREAM, 0);
        if (sock_fd < 0) {
                perror("socket fd err");
                return sock_fd;
        }

        hint.ai_family = domain;
        hint.ai_socktype = SOCK_STREAM;

        err = getaddrinfo(addr, port, &hint, &res);
        if (err) {
                perror("getaddrinfo failed");
                goto cleanup;
        }

        if (opt) {
                err = setsockopt(sock_fd, SOL_SOCKET, opt, &reuse, sizeof(reuse));
                if (err) {
                        perror("setsockopt failed");
                        goto cleanup;
                }
        }

        err = bind(sock_fd, res->ai_addr, res->ai_addrlen);
        if (err) {
                perror("failed to bind to port");
                goto cleanup;
        }

        return sock_fd;

cleanup:
        close(sock_fd);
        return err;
}

static void *setup(void *arg)
{
        int sock_fd, i;
        int *array = (int *)arg;

        for (i = 0; i < MAX_CONNECTIONS; i++) {
                sock_fd = bind_socket(SO_REUSEPORT, setup_addr);
                if (sock_fd < 0) {
                        ret = sock_fd;
                        pthread_exit(&ret);
                }
                array[i] = sock_fd;
        }

        return NULL;
}

int main(int argc, const char *argv[])
{
        int listener_fd, sock_fd, i, j;
        pthread_t tid[MAX_THREADS];
        clock_t begin, end;

        if (argc != 4) {
                printf("Usage: listener <port> <ipv6 | ipv4> <bind-addr>\n");
                return -1;
        }

        port = argv[1];
        use_v6 = strcmp(argv[2], "ipv6") == 0;
        bind_addr = argv[3];

        setup_addr = use_v6 ? setup_addr_v6 : setup_addr_v4;

        listener_fd = bind_socket(SO_REUSEPORT, setup_addr);
        if (listen(listener_fd, 100) < 0) {
                perror("listen failed");
                return -1;
        }

        /* Set up threads to populate the bhash table entry for the port */
        for (i = 0; i < MAX_THREADS; i++)
                pthread_create(&tid[i], NULL, setup, fd_array[i]);

        for (i = 0; i < MAX_THREADS; i++)
                pthread_join(tid[i], NULL);

        if (ret)
                goto done;

        begin = clock();

        /* Bind to the same port on a different address */
        sock_fd  = bind_socket(0, bind_addr);
        if (sock_fd < 0)
                goto done;

        end = clock();

        printf("time spent = %f\n", (double)(end - begin) / CLOCKS_PER_SEC);

        /* clean up */
        close(sock_fd);

done:
        close(listener_fd);
        for (i = 0; i < MAX_THREADS; i++) {
                for (j = 0; i < MAX_THREADS; i++)
                        close(fd_array[i][j]);
        }

        return 0;
}