/*-
 * Copyright (c) 2004 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/poll.h>

#include <netinet/in.h>
#include <netdb.h>          /* getaddrinfo */

#include <arpa/inet.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>         /* close */

#define MAXSOCK 20

#include <pthread.h>
#include <fcntl.h>
#include <time.h>       /* clock_getres() */

static int round_to(int n, int l)
{
        return ((n + l - 1)/l)*l;
}

/*
 * Each socket uses multiple threads so the receiver is
 * more efficient. A collector thread runs the stats.
 */
struct td_desc {
        pthread_t td_id;
        uint64_t count; /* rx counter */
        uint64_t byte_count;    /* rx byte counter */
        int fd;
        char *buf;
        int buflen;
};

static void
usage(void)
{

        fprintf(stderr, "netreceive port [nthreads]\n");
        exit(-1);
}

static __inline void
timespec_add(struct timespec *tsa, struct timespec *tsb)
{

        tsa->tv_sec += tsb->tv_sec;
        tsa->tv_nsec += tsb->tv_nsec;
        if (tsa->tv_nsec >= 1000000000) {
                tsa->tv_sec++;
                tsa->tv_nsec -= 1000000000;
        }
}

static __inline void
timespec_sub(struct timespec *tsa, struct timespec *tsb)
{

        tsa->tv_sec -= tsb->tv_sec;
        tsa->tv_nsec -= tsb->tv_nsec;
        if (tsa->tv_nsec < 0) {
                tsa->tv_sec--;
                tsa->tv_nsec += 1000000000;
        }
}

static void *
rx_body(void *data)
{
        struct td_desc *t = data;
        struct pollfd fds;
        int y;

        fds.fd = t->fd;
        fds.events = POLLIN;

        for (;;) {
                if (poll(&fds, 1, -1) < 0) 
                        perror("poll on thread");
                if (!(fds.revents & POLLIN))
                        continue;
                for (;;) {
                        y = recv(t->fd, t->buf, t->buflen, MSG_DONTWAIT);
                        if (y < 0)
                                break;
                        t->count++;
                        t->byte_count += y;
                }
        }
        return NULL;
}

static struct td_desc **
make_threads(int *s, int nsock, int nthreads)
{
        int i, si, nt = nsock * nthreads;
        int lb = round_to(nt * sizeof (struct td_desc *), 64);
        int td_len = round_to(sizeof(struct td_desc), 64); // cache align
        char *m = calloc(1, lb + td_len * nt);
        struct td_desc **tp;

        printf("td len %d -> %d\n", (int)sizeof(struct td_desc) , td_len);
        /* pointers plus the structs */
        if (m == NULL) {
                perror("no room for pointers!");
                exit(1);
        }
        tp = (struct td_desc **)m;
        m += lb;        /* skip the pointers */
        for (si = i = 0; i < nt; i++, m += td_len) {
                tp[i] = (struct td_desc *)m;
                tp[i]->fd = s[si];
                tp[i]->buflen = 65536;
                tp[i]->buf = calloc(1, tp[i]->buflen);
                if (++si == nsock)
                        si = 0;
                if (pthread_create(&tp[i]->td_id, NULL, rx_body, tp[i])) {
                        perror("unable to create thread");
                        exit(1);
                }
        }
        return tp;
}

static void
main_thread(struct td_desc **tp, int nsock, int nthreads)
{
        uint64_t c0, c1, bc0, bc1;
        struct timespec now, then, delta;
        /* now the parent collects and prints results */
        c0 = c1 = bc0 = bc1 = 0;
        clock_gettime(CLOCK_REALTIME, &then);
        fprintf(stderr, "start at %ld.%09ld\n", then.tv_sec, then.tv_nsec);
        while (1) {
                int i, nt = nsock * nthreads;
                int64_t dn;
                uint64_t pps, bps;

                if (poll(NULL, 0, 500) < 0) 
                        perror("poll");
                c0 = bc0 = 0;
                for (i = 0; i < nt; i++) {
                        c0 += tp[i]->count;
                        bc0 += tp[i]->byte_count;
                }
                dn = c0 - c1;
                clock_gettime(CLOCK_REALTIME, &now);
                delta = now;
                timespec_sub(&delta, &then);
                then = now;
                pps = dn;
                pps = (pps * 1000000000) / (delta.tv_sec*1000000000 + delta.tv_nsec + 1);
                bps = ((bc0 - bc1) * 8000000000) / (delta.tv_sec*1000000000 + delta.tv_nsec + 1);
                fprintf(stderr, " %9ld pps %8.3f Mbps", (long)pps, .000001*bps);
                fprintf(stderr, " - %d pkts in %ld.%09ld ns\n",
                        (int)dn, delta.tv_sec, delta.tv_nsec);
                c1 = c0;
                bc1 = bc0;
        }
}

int
main(int argc, char *argv[])
{
        struct addrinfo hints, *res, *res0;
        char *dummy, *packet;
        int port;
        int error, v, nthreads = 1;
        struct td_desc **tp;
        const char *cause = NULL;
        int s[MAXSOCK];
        int nsock;

        if (argc < 2)
                usage();

        memset(&hints, 0, sizeof(hints));
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_flags = AI_PASSIVE;

        port = strtoul(argv[1], &dummy, 10);
        if (port < 1 || port > 65535 || *dummy != '\0')
                usage();
        if (argc > 2)
                nthreads = strtoul(argv[2], &dummy, 10);
        if (nthreads < 1 || nthreads > 64)
                usage();

        packet = malloc(65536);
        if (packet == NULL) {
                perror("malloc");
                return (-1);
        }
        bzero(packet, 65536);

        error = getaddrinfo(NULL, argv[1], &hints, &res0);
        if (error) {
                perror(gai_strerror(error));
                return (-1);
                /*NOTREACHED*/
        }

        nsock = 0;
        for (res = res0; res && nsock < MAXSOCK; res = res->ai_next) {
                s[nsock] = socket(res->ai_family, res->ai_socktype,
                res->ai_protocol);
                if (s[nsock] < 0) {
                        cause = "socket";
                        continue;
                }

                v = 128 * 1024;
                if (setsockopt(s[nsock], SOL_SOCKET, SO_RCVBUF, &v, sizeof(v)) < 0) {
                        cause = "SO_RCVBUF";
                        close(s[nsock]);
                        continue;
                }
                if (bind(s[nsock], res->ai_addr, res->ai_addrlen) < 0) {
                        cause = "bind";
                        close(s[nsock]);
                        continue;
                }
                (void) listen(s[nsock], 5);
                nsock++;
        }
        if (nsock == 0) {
                perror(cause);
                return (-1);
                /*NOTREACHED*/
        }

        printf("netreceive %d sockets x %d threads listening on UDP port %d\n",
                nsock, nthreads, (u_short)port);

        tp = make_threads(s, nsock, nthreads);
        main_thread(tp, nsock, nthreads);

        /*NOTREACHED*/
        freeaddrinfo(res0);
}