xref: /freebsd-11-stable/tools/tools/netmap/pkt-gen.c

/*
 * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. 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.
 */

/*
 * $FreeBSD: head/tools/tools/netmap/pkt-gen.c 238165 2012-07-06 13:21:23Z emaste $
 * $Id: pkt-gen.c 10967 2012-05-03 11:29:23Z luigi $
 *
 * Example program to show how to build a multithreaded packet
 * source/sink using the netmap device.
 *
 * In this example we create a programmable number of threads
 * to take care of all the queues of the interface used to
 * send or receive traffic.
 *
 */

const char *default_payload="netmap pkt-gen Luigi Rizzo and Matteo Landi\n"
	"http://info.iet.unipi.it/~luigi/netmap/ ";

#include <errno.h>
#include <pthread.h>	/* pthread_* */
#include <pthread_np.h>	/* pthread w/ affinity */
#include <signal.h>	/* signal */
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>	/* PRI* macros */
#include <string.h>	/* strcmp */
#include <fcntl.h>	/* open */
#include <unistd.h>	/* close */
#include <ifaddrs.h>	/* getifaddrs */

#include <sys/mman.h>	/* PROT_* */
#include <sys/ioctl.h>	/* ioctl */
#include <sys/poll.h>
#include <sys/socket.h>	/* sockaddr.. */
#include <arpa/inet.h>	/* ntohs */
#include <sys/param.h>
#include <sys/cpuset.h>	/* cpu_set */
#include <sys/sysctl.h>	/* sysctl */
#include <sys/time.h>	/* timersub */

#include <net/ethernet.h>
#include <net/if.h>	/* ifreq */
#include <net/if_dl.h>	/* LLADDR */

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>

#include <net/netmap.h>
#include <net/netmap_user.h>
#include <pcap/pcap.h>


static inline int min(int a, int b) { return a < b ? a : b; }

/* debug support */
#define D(format, ...)				\
	fprintf(stderr, "%s [%d] " format "\n", 	\
	__FUNCTION__, __LINE__, ##__VA_ARGS__)

#ifndef EXPERIMENTAL
#define EXPERIMENTAL 0
#endif

int verbose = 0;
#define MAX_QUEUES 64	/* no need to limit */

#define SKIP_PAYLOAD 1 /* do not check payload. */

inline void prefetch (const void *x)
{
        __asm volatile("prefetcht0 %0" :: "m" (*(const unsigned long *)x));
}

// XXX only for multiples of 64 bytes, non overlapped.
static inline void
pkt_copy(void *_src, void *_dst, int l)
{
	uint64_t *src = _src;
	uint64_t *dst = _dst;
#define likely(x)       __builtin_expect(!!(x), 1)
#define unlikely(x)       __builtin_expect(!!(x), 0)
	if (unlikely(l >= 1024)) {
		bcopy(src, dst, l);
		return;
	}
	for (; l > 0; l-=64) {
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
	}
}


#if EXPERIMENTAL
/* Wrapper around `rdtsc' to take reliable timestamps flushing the pipeline */
#define netmap_rdtsc(t) \
	do { \
		u_int __regs[4];					\
									\
		do_cpuid(0, __regs);					\
		(t) = rdtsc();						\
	} while (0)

static __inline void
do_cpuid(u_int ax, u_int *p)
{
	__asm __volatile("cpuid"
			 : "=a" (p[0]), "=b" (p[1]), "=c" (p[2]), "=d" (p[3])
			 :  "0" (ax));
}

static __inline uint64_t
rdtsc(void)
{
	uint64_t rv;

	__asm __volatile("rdtsc" : "=A" (rv));
	return (rv);
}
#define MAX_SAMPLES 100000
#endif /* EXPERIMENTAL */


struct pkt {
	struct ether_header eh;
	struct ip ip;
	struct udphdr udp;
	uint8_t body[2048];	// XXX hardwired
} __attribute__((__packed__));

/*
 * global arguments for all threads
 */
struct glob_arg {
	const char *src_ip;
	const char *dst_ip;
	const char *src_mac;
	const char *dst_mac;
	int pkt_size;
	int burst;
	int npackets;	/* total packets to send */
	int nthreads;
	int cpus;
	int options;	/* testing */
#define OPT_PREFETCH	1
#define OPT_ACCESS	2
#define OPT_COPY	4
#define OPT_MEMCPY	8
	int use_pcap;
	pcap_t *p;
};

struct mystat {
	uint64_t containers[8];
};

/*
 * Arguments for a new thread. The same structure is used by
 * the source and the sink
 */
struct targ {
	struct glob_arg *g;
	int used;
	int completed;
	int cancel;
	int fd;
	struct nmreq nmr;
	struct netmap_if *nifp;
	uint16_t	qfirst, qlast; /* range of queues to scan */
	uint64_t count;
	struct timeval tic, toc;
	int me;
	pthread_t thread;
	int affinity;

	uint8_t	dst_mac[6];
	uint8_t	src_mac[6];
	u_int dst_mac_range;
	u_int src_mac_range;
	uint32_t dst_ip;
	uint32_t src_ip;
	u_int dst_ip_range;
	u_int src_ip_range;

	struct pkt pkt;
};


static struct targ *targs;
static int global_nthreads;

/* control-C handler */
static void
sigint_h(__unused int sig)
{
	for (int i = 0; i < global_nthreads; i++)
		targs[i].cancel = 1;

	signal(SIGINT, SIG_DFL);
}


/* sysctl wrapper to return the number of active CPUs */
static int
system_ncpus(void)
{
	int mib[2], ncpus;
	size_t len;

	mib[0] = CTL_HW;
	mib[1] = HW_NCPU;
	len = sizeof(mib);
	sysctl(mib, 2, &ncpus, &len, NULL, 0);

	return (ncpus);
}

/*
 * locate the src mac address for our interface, put it
 * into the user-supplied buffer. return 0 if ok, -1 on error.
 */
static int
source_hwaddr(const char *ifname, char *buf)
{
	struct ifaddrs *ifaphead, *ifap;
	int l = sizeof(ifap->ifa_name);

	if (getifaddrs(&ifaphead) != 0) {
		D("getifaddrs %s failed", ifname);
		return (-1);
	}

	for (ifap = ifaphead; ifap; ifap = ifap->ifa_next) {
		struct sockaddr_dl *sdl =
			(struct sockaddr_dl *)ifap->ifa_addr;
		uint8_t *mac;

		if (!sdl || sdl->sdl_family != AF_LINK)
			continue;
		if (strncmp(ifap->ifa_name, ifname, l) != 0)
			continue;
		mac = (uint8_t *)LLADDR(sdl);
		sprintf(buf, "%02x:%02x:%02x:%02x:%02x:%02x",
			mac[0], mac[1], mac[2],
			mac[3], mac[4], mac[5]);
		if (verbose)
			D("source hwaddr %s", buf);
		break;
	}
	freeifaddrs(ifaphead);
	return ifap ? 0 : 1;
}


/* set the thread affinity. */
static int
setaffinity(pthread_t me, int i)
{
	cpuset_t cpumask;

	if (i == -1)
		return 0;

	/* Set thread affinity affinity.*/
	CPU_ZERO(&cpumask);
	CPU_SET(i, &cpumask);

	if (pthread_setaffinity_np(me, sizeof(cpuset_t), &cpumask) != 0) {
		D("Unable to set affinity");
		return 1;
	}
	return 0;
}

/* Compute the checksum of the given ip header. */
static uint16_t
checksum(const void *data, uint16_t len)
{
        const uint8_t *addr = data;
        uint32_t sum = 0;

        while (len > 1) {
                sum += addr[0] * 256 + addr[1];
                addr += 2;
                len -= 2;
        }

        if (len == 1)
                sum += *addr * 256;

        sum = (sum >> 16) + (sum & 0xffff);
        sum += (sum >> 16);

        sum = htons(sum);

        return ~sum;
}

/*
 * Fill a packet with some payload.
 */
static void
initialize_packet(struct targ *targ)
{
	struct pkt *pkt = &targ->pkt;
	struct ether_header *eh;
	struct ip *ip;
	struct udphdr *udp;
	uint16_t paylen = targ->g->pkt_size - sizeof(*eh) - sizeof(*ip);
	int i, l, l0 = strlen(default_payload);
	char *p;

	for (i = 0; i < paylen;) {
		l = min(l0, paylen - i);
		bcopy(default_payload, pkt->body + i, l);
		i += l;
	}
	pkt->body[i-1] = '\0';

	udp = &pkt->udp;
	udp->uh_sport = htons(1234);
        udp->uh_dport = htons(4321);
	udp->uh_ulen = htons(paylen);
	udp->uh_sum = 0; // checksum(udp, sizeof(*udp));

	ip = &pkt->ip;
        ip->ip_v = IPVERSION;
        ip->ip_hl = 5;
        ip->ip_id = 0;
        ip->ip_tos = IPTOS_LOWDELAY;
	ip->ip_len = ntohs(targ->g->pkt_size - sizeof(*eh));
        ip->ip_id = 0;
        ip->ip_off = htons(IP_DF); /* Don't fragment */
        ip->ip_ttl = IPDEFTTL;
	ip->ip_p = IPPROTO_UDP;
	inet_aton(targ->g->src_ip, (struct in_addr *)&ip->ip_src);
	inet_aton(targ->g->dst_ip, (struct in_addr *)&ip->ip_dst);
	targ->dst_ip = ip->ip_dst.s_addr;
	targ->src_ip = ip->ip_src.s_addr;
	p = index(targ->g->src_ip, '-');
	if (p) {
		targ->dst_ip_range = atoi(p+1);
		D("dst-ip sweep %d addresses", targ->dst_ip_range);
	}
	ip->ip_sum = checksum(ip, sizeof(*ip));

	eh = &pkt->eh;
	bcopy(ether_aton(targ->g->src_mac), targ->src_mac, 6);
	bcopy(targ->src_mac, eh->ether_shost, 6);
	p = index(targ->g->src_mac, '-');
	if (p)
		targ->src_mac_range = atoi(p+1);

	bcopy(ether_aton(targ->g->dst_mac), targ->dst_mac, 6);
	bcopy(targ->dst_mac, eh->ether_dhost, 6);
	p = index(targ->g->dst_mac, '-');
	if (p)
		targ->dst_mac_range = atoi(p+1);
	eh->ether_type = htons(ETHERTYPE_IP);
}

/* Check the payload of the packet for errors (use it for debug).
 * Look for consecutive ascii representations of the size of the packet.
 */
static void
check_payload(char *p, int psize)
{
	char temp[64];
	int n_read, size, sizelen;

	/* get the length in ASCII of the length of the packet. */
	sizelen = sprintf(temp, "%d", psize) + 1; // include a whitespace

	/* dummy payload. */
	p += 14; /* skip packet header. */
	n_read = 14;
	while (psize - n_read >= sizelen) {
		sscanf(p, "%d", &size);
		if (size != psize) {
			D("Read %d instead of %d", size, psize);
			break;
		}

		p += sizelen;
		n_read += sizelen;
	}
}


/*
 * create and enqueue a batch of packets on a ring.
 * On the last one set NS_REPORT to tell the driver to generate
 * an interrupt when done.
 */
static int
send_packets(struct netmap_ring *ring, struct pkt *pkt,
		int size, u_int count, int options)
{
	u_int sent, cur = ring->cur;

	if (ring->avail < count)
		count = ring->avail;

#if 0
	if (options & (OPT_COPY | OPT_PREFETCH) ) {
		for (sent = 0; sent < count; sent++) {
			struct netmap_slot *slot = &ring->slot[cur];
			char *p = NETMAP_BUF(ring, slot->buf_idx);

			prefetch(p);
			cur = NETMAP_RING_NEXT(ring, cur);
		}
		cur = ring->cur;
	}
#endif
	for (sent = 0; sent < count; sent++) {
		struct netmap_slot *slot = &ring->slot[cur];
		char *p = NETMAP_BUF(ring, slot->buf_idx);

		if (options & OPT_COPY)
			pkt_copy(pkt, p, size);
		else if (options & OPT_MEMCPY)
			memcpy(p, pkt, size);
		else if (options & OPT_PREFETCH)
			prefetch(p);

		slot->len = size;
		if (sent == count - 1)
			slot->flags |= NS_REPORT;
		cur = NETMAP_RING_NEXT(ring, cur);
	}
	ring->avail -= sent;
	ring->cur = cur;

	return (sent);
}

static void *
sender_body(void *data)
{
	struct targ *targ = (struct targ *) data;

	struct pollfd fds[1];
	struct netmap_if *nifp = targ->nifp;
	struct netmap_ring *txring;
	int i, n = targ->g->npackets / targ->g->nthreads, sent = 0;
	int options = targ->g->options | OPT_COPY;
D("start");
	if (setaffinity(targ->thread, targ->affinity))
		goto quit;
	/* setup poll(2) mechanism. */
	memset(fds, 0, sizeof(fds));
	fds[0].fd = targ->fd;
	fds[0].events = (POLLOUT);

	/* main loop.*/
	gettimeofday(&targ->tic, NULL);
    if (targ->g->use_pcap) {
	int size = targ->g->pkt_size;
	void *pkt = &targ->pkt;
	pcap_t *p = targ->g->p;

	for (i = 0; sent < n && !targ->cancel; i++) {
		if (pcap_inject(p, pkt, size) != -1)
			sent++;
		if (i > 10000) {
			targ->count = sent;
			i = 0;
		}
	}
    } else {
	while (sent < n) {

		/*
		 * wait for available room in the send queue(s)
		 */
		if (poll(fds, 1, 2000) <= 0) {
			if (targ->cancel)
				break;
			D("poll error/timeout on queue %d\n", targ->me);
			goto quit;
		}
		/*
		 * scan our queues and send on those with room
		 */
		if (sent > 100000 && !(targ->g->options & OPT_COPY) )
			options &= ~OPT_COPY;
		for (i = targ->qfirst; i < targ->qlast && !targ->cancel; i++) {
			int m, limit = MIN(n - sent, targ->g->burst);

			txring = NETMAP_TXRING(nifp, i);
			if (txring->avail == 0)
				continue;
			m = send_packets(txring, &targ->pkt, targ->g->pkt_size,
					 limit, options);
			sent += m;
			targ->count = sent;
		}
		if (targ->cancel)
			break;
	}
	/* flush any remaining packets */
	ioctl(fds[0].fd, NIOCTXSYNC, NULL);

	/* final part: wait all the TX queues to be empty. */
	for (i = targ->qfirst; i < targ->qlast; i++) {
		txring = NETMAP_TXRING(nifp, i);
		while (!NETMAP_TX_RING_EMPTY(txring)) {
			ioctl(fds[0].fd, NIOCTXSYNC, NULL);
			usleep(1); /* wait 1 tick */
		}
	}
    }

	gettimeofday(&targ->toc, NULL);
	targ->completed = 1;
	targ->count = sent;

quit:
	/* reset the ``used`` flag. */
	targ->used = 0;

	return (NULL);
}


static void
receive_pcap(u_char *user, __unused const struct pcap_pkthdr * h,
	__unused const u_char * bytes)
{
	int *count = (int *)user;
	(*count)++;
}

static int
receive_packets(struct netmap_ring *ring, u_int limit, int skip_payload)
{
	u_int cur, rx;

	cur = ring->cur;
	if (ring->avail < limit)
		limit = ring->avail;
	for (rx = 0; rx < limit; rx++) {
		struct netmap_slot *slot = &ring->slot[cur];
		char *p = NETMAP_BUF(ring, slot->buf_idx);

		if (!skip_payload)
			check_payload(p, slot->len);

		cur = NETMAP_RING_NEXT(ring, cur);
	}
	ring->avail -= rx;
	ring->cur = cur;

	return (rx);
}

static void *
receiver_body(void *data)
{
	struct targ *targ = (struct targ *) data;
	struct pollfd fds[1];
	struct netmap_if *nifp = targ->nifp;
	struct netmap_ring *rxring;
	int i, received = 0;

	if (setaffinity(targ->thread, targ->affinity))
		goto quit;

	/* setup poll(2) mechanism. */
	memset(fds, 0, sizeof(fds));
	fds[0].fd = targ->fd;
	fds[0].events = (POLLIN);

	/* unbounded wait for the first packet. */
	for (;;) {
		i = poll(fds, 1, 1000);
		if (i > 0 && !(fds[0].revents & POLLERR))
			break;
		D("waiting for initial packets, poll returns %d %d", i, fds[0].revents);
	}

	/* main loop, exit after 1s silence */
	gettimeofday(&targ->tic, NULL);
    if (targ->g->use_pcap) {
	while (!targ->cancel) {
		pcap_dispatch(targ->g->p, targ->g->burst, receive_pcap, NULL);
	}
    } else {
	while (!targ->cancel) {
		/* Once we started to receive packets, wait at most 1 seconds
		   before quitting. */
		if (poll(fds, 1, 1 * 1000) <= 0) {
			gettimeofday(&targ->toc, NULL);
			targ->toc.tv_sec -= 1; /* Subtract timeout time. */
			break;
		}

		for (i = targ->qfirst; i < targ->qlast; i++) {
			int m;

			rxring = NETMAP_RXRING(nifp, i);
			if (rxring->avail == 0)
				continue;

			m = receive_packets(rxring, targ->g->burst,
					SKIP_PAYLOAD);
			received += m;
			targ->count = received;
		}

		// tell the card we have read the data
		//ioctl(fds[0].fd, NIOCRXSYNC, NULL);
	}
    }

	targ->completed = 1;
	targ->count = received;

quit:
	/* reset the ``used`` flag. */
	targ->used = 0;

	return (NULL);
}

static void
tx_output(uint64_t sent, int size, double delta)
{
	double amount = 8.0 * (1.0 * size * sent) / delta;
	double pps = sent / delta;
	char units[4] = { '\0', 'K', 'M', 'G' };
	int aunit = 0, punit = 0;

	while (amount >= 1000) {
		amount /= 1000;
		aunit += 1;
	}
	while (pps >= 1000) {
		pps /= 1000;
		punit += 1;
	}

	printf("Sent %" PRIu64 " packets, %d bytes each, in %.2f seconds.\n",
	       sent, size, delta);
	printf("Speed: %.2f%cpps. Bandwidth: %.2f%cbps.\n",
	       pps, units[punit], amount, units[aunit]);
}


static void
rx_output(uint64_t received, double delta)
{

	double pps = received / delta;
	char units[4] = { '\0', 'K', 'M', 'G' };
	int punit = 0;

	while (pps >= 1000) {
		pps /= 1000;
		punit += 1;
	}

	printf("Received %" PRIu64 " packets, in %.2f seconds.\n", received, delta);
	printf("Speed: %.2f%cpps.\n", pps, units[punit]);
}

static void
usage(void)
{
	const char *cmd = "pkt-gen";
	fprintf(stderr,
		"Usage:\n"
		"%s arguments\n"
		"\t-i interface		interface name\n"
		"\t-t pkts_to_send	also forces send mode\n"
		"\t-r pkts_to_receive	also forces receive mode\n"
		"\t-l pkts_size		in bytes excluding CRC\n"
		"\t-d dst-ip		end with %%n to sweep n addresses\n"
		"\t-s src-ip		end with %%n to sweep n addresses\n"
		"\t-D dst-mac		end with %%n to sweep n addresses\n"
		"\t-S src-mac		end with %%n to sweep n addresses\n"
		"\t-b burst size		testing, mostly\n"
		"\t-c cores		cores to use\n"
		"\t-p threads		processes/threads to use\n"
		"\t-T report_ms		milliseconds between reports\n"
		"\t-w wait_for_link_time	in seconds\n"
		"",
		cmd);

	exit(0);
}


int
main(int arc, char **argv)
{
	int i, fd;
	char pcap_errbuf[PCAP_ERRBUF_SIZE];

	struct glob_arg g;

	struct nmreq nmr;
	void *mmap_addr;		/* the mmap address */
	void *(*td_body)(void *) = receiver_body;
	int ch;
	int report_interval = 1000;	/* report interval */
	char *ifname = NULL;
	int wait_link = 2;
	int devqueues = 1;	/* how many device queues */

	bzero(&g, sizeof(g));

	g.src_ip = "10.0.0.1";
	g.dst_ip = "10.1.0.1";
	g.dst_mac = "ff:ff:ff:ff:ff:ff";
	g.src_mac = NULL;
	g.pkt_size = 60;
	g.burst = 512;		// default
	g.nthreads = 1;
	g.cpus = 1;

	while ( (ch = getopt(arc, argv,
			"i:t:r:l:d:s:D:S:b:c:o:p:PT:w:v")) != -1) {
		switch(ch) {
		default:
			D("bad option %c %s", ch, optarg);
			usage();
			break;
		case 'o':
			g.options = atoi(optarg);
			break;
		case 'i':	/* interface */
			ifname = optarg;
			break;
		case 't':	/* send */
			td_body = sender_body;
			g.npackets = atoi(optarg);
			break;
		case 'r':	/* receive */
			td_body = receiver_body;
			g.npackets = atoi(optarg);
			break;
		case 'l':	/* pkt_size */
			g.pkt_size = atoi(optarg);
			break;
		case 'd':
			g.dst_ip = optarg;
			break;
		case 's':
			g.src_ip = optarg;
			break;
		case 'T':	/* report interval */
			report_interval = atoi(optarg);
			break;
		case 'w':
			wait_link = atoi(optarg);
			break;
		case 'b':	/* burst */
			g.burst = atoi(optarg);
			break;
		case 'c':
			g.cpus = atoi(optarg);
			break;
		case 'p':
			g.nthreads = atoi(optarg);
			break;

		case 'P':
			g.use_pcap = 1;
			break;

		case 'D': /* destination mac */
			g.dst_mac = optarg;
	{
		struct ether_addr *mac = ether_aton(g.dst_mac);
		D("ether_aton(%s) gives %p", g.dst_mac, mac);
	}
			break;
		case 'S': /* source mac */
			g.src_mac = optarg;
			break;
		case 'v':
			verbose++;
		}
	}

	if (ifname == NULL) {
		D("missing ifname");
		usage();
	}
	{
		int n = system_ncpus();
		if (g.cpus < 0 || g.cpus > n) {
			D("%d cpus is too high, have only %d cpus", g.cpus, n);
			usage();
		}
		if (g.cpus == 0)
			g.cpus = n;
	}
	if (g.pkt_size < 16 || g.pkt_size > 1536) {
		D("bad pktsize %d\n", g.pkt_size);
		usage();
	}

	if (td_body == sender_body && g.src_mac == NULL) {
		static char mybuf[20] = "ff:ff:ff:ff:ff:ff";
		/* retrieve source mac address. */
		if (source_hwaddr(ifname, mybuf) == -1) {
			D("Unable to retrieve source mac");
			// continue, fail later
		}
		g.src_mac = mybuf;
	}

    if (g.use_pcap) {
	D("using pcap on %s", ifname);
	g.p = pcap_open_live(ifname, 0, 1, 100, pcap_errbuf);
	if (g.p == NULL) {
		D("cannot open pcap on %s", ifname);
		usage();
	}
	mmap_addr = NULL;
	fd = -1;
    } else {
	bzero(&nmr, sizeof(nmr));
	nmr.nr_version = NETMAP_API;
	/*
	 * Open the netmap device to fetch the number of queues of our
	 * interface.
	 *
	 * The first NIOCREGIF also detaches the card from the
	 * protocol stack and may cause a reset of the card,
	 * which in turn may take some time for the PHY to
	 * reconfigure.
	 */
	fd = open("/dev/netmap", O_RDWR);
	if (fd == -1) {
		D("Unable to open /dev/netmap");
		// fail later
	} else {
		if ((ioctl(fd, NIOCGINFO, &nmr)) == -1) {
			D("Unable to get if info without name");
		} else {
			D("map size is %d Kb", nmr.nr_memsize >> 10);
		}
		bzero(&nmr, sizeof(nmr));
		nmr.nr_version = NETMAP_API;
		strncpy(nmr.nr_name, ifname, sizeof(nmr.nr_name));
		if ((ioctl(fd, NIOCGINFO, &nmr)) == -1) {
			D("Unable to get if info for %s", ifname);
		}
		devqueues = nmr.nr_rx_rings;
	}

	/* validate provided nthreads. */
	if (g.nthreads < 1 || g.nthreads > devqueues) {
		D("bad nthreads %d, have %d queues", g.nthreads, devqueues);
		// continue, fail later
	}

	/*
	 * Map the netmap shared memory: instead of issuing mmap()
	 * inside the body of the threads, we prefer to keep this
	 * operation here to simplify the thread logic.
	 */
	D("mmapping %d Kbytes", nmr.nr_memsize>>10);
	mmap_addr = (struct netmap_d *) mmap(0, nmr.nr_memsize,
					    PROT_WRITE | PROT_READ,
					    MAP_SHARED, fd, 0);
	if (mmap_addr == MAP_FAILED) {
		D("Unable to mmap %d KB", nmr.nr_memsize >> 10);
		// continue, fail later
	}

	/*
	 * Register the interface on the netmap device: from now on,
	 * we can operate on the network interface without any
	 * interference from the legacy network stack.
	 *
	 * We decide to put the first interface registration here to
	 * give time to cards that take a long time to reset the PHY.
	 */
	nmr.nr_version = NETMAP_API;
	if (ioctl(fd, NIOCREGIF, &nmr) == -1) {
		D("Unable to register interface %s", ifname);
		//continue, fail later
	}


	/* Print some debug information. */
	fprintf(stdout,
		"%s %s: %d queues, %d threads and %d cpus.\n",
		(td_body == sender_body) ? "Sending on" : "Receiving from",
		ifname,
		devqueues,
		g.nthreads,
		g.cpus);
	if (td_body == sender_body) {
		fprintf(stdout, "%s -> %s (%s -> %s)\n",
			g.src_ip, g.dst_ip,
			g.src_mac, g.dst_mac);
	}

	/* Exit if something went wrong. */
	if (fd < 0) {
		D("aborting");
		usage();
	}
    }

	if (g.options) {
		D("special options:%s%s%s%s\n",
			g.options & OPT_PREFETCH ? " prefetch" : "",
			g.options & OPT_ACCESS ? " access" : "",
			g.options & OPT_MEMCPY ? " memcpy" : "",
			g.options & OPT_COPY ? " copy" : "");
	}
	/* Wait for PHY reset. */
	D("Wait %d secs for phy reset", wait_link);
	sleep(wait_link);
	D("Ready...");

	/* Install ^C handler. */
	global_nthreads = g.nthreads;
	signal(SIGINT, sigint_h);

	if (g.use_pcap) {
		g.p = pcap_open_live(ifname, 0, 1, 100, NULL);
		if (g.p == NULL) {
			D("cannot open pcap on %s", ifname);
			usage();
		} else
			D("using pcap %p on %s", g.p, ifname);
	}

	targs = calloc(g.nthreads, sizeof(*targs));
	/*
	 * Now create the desired number of threads, each one
	 * using a single descriptor.
 	 */
	for (i = 0; i < g.nthreads; i++) {
		struct netmap_if *tnifp;
		struct nmreq tifreq;
		int tfd;

	    if (g.use_pcap) {
		tfd = -1;
		tnifp = NULL;
	    } else {
		/* register interface. */
		tfd = open("/dev/netmap", O_RDWR);
		if (tfd == -1) {
			D("Unable to open /dev/netmap");
			continue;
		}

		bzero(&tifreq, sizeof(tifreq));
		strncpy(tifreq.nr_name, ifname, sizeof(tifreq.nr_name));
		tifreq.nr_version = NETMAP_API;
		tifreq.nr_ringid = (g.nthreads > 1) ? (i | NETMAP_HW_RING) : 0;

		/*
		 * if we are acting as a receiver only, do not touch the transmit ring.
		 * This is not the default because many apps may use the interface
		 * in both directions, but a pure receiver does not.
		 */
		if (td_body == receiver_body) {
			tifreq.nr_ringid |= NETMAP_NO_TX_POLL;
		}

		if ((ioctl(tfd, NIOCREGIF, &tifreq)) == -1) {
			D("Unable to register %s", ifname);
			continue;
		}
		tnifp = NETMAP_IF(mmap_addr, tifreq.nr_offset);
	    }
		/* start threads. */
		bzero(&targs[i], sizeof(targs[i]));
		targs[i].g = &g;
		targs[i].used = 1;
		targs[i].completed = 0;
		targs[i].fd = tfd;
		targs[i].nmr = tifreq;
		targs[i].nifp = tnifp;
		targs[i].qfirst = (g.nthreads > 1) ? i : 0;
		targs[i].qlast = (g.nthreads > 1) ? i+1 :
			(td_body == receiver_body ? tifreq.nr_rx_rings : tifreq.nr_tx_rings);
		targs[i].me = i;
		targs[i].affinity = g.cpus ? i % g.cpus : -1;
		if (td_body == sender_body) {
			/* initialize the packet to send. */
			initialize_packet(&targs[i]);
		}

		if (pthread_create(&targs[i].thread, NULL, td_body,
				   &targs[i]) == -1) {
			D("Unable to create thread %d", i);
			targs[i].used = 0;
		}
	}

    {
	uint64_t my_count = 0, prev = 0;
	uint64_t count = 0;
	double delta_t;
	struct timeval tic, toc;

	gettimeofday(&toc, NULL);
	for (;;) {
		struct timeval now, delta;
		uint64_t pps;
		int done = 0;

		delta.tv_sec = report_interval/1000;
		delta.tv_usec = (report_interval%1000)*1000;
		select(0, NULL, NULL, NULL, &delta);
		gettimeofday(&now, NULL);
		timersub(&now, &toc, &toc);
		my_count = 0;
		for (i = 0; i < g.nthreads; i++) {
			my_count += targs[i].count;
			if (targs[i].used == 0)
				done++;
		}
		pps = toc.tv_sec* 1000000 + toc.tv_usec;
		if (pps < 10000)
			continue;
		pps = (my_count - prev)*1000000 / pps;
		D("%" PRIu64 " pps", pps);
		prev = my_count;
		toc = now;
		if (done == g.nthreads)
			break;
	}

	timerclear(&tic);
	timerclear(&toc);
	for (i = 0; i < g.nthreads; i++) {
		/*
		 * Join active threads, unregister interfaces and close
		 * file descriptors.
		 */
		pthread_join(targs[i].thread, NULL);
		ioctl(targs[i].fd, NIOCUNREGIF, &targs[i].nmr);
		close(targs[i].fd);

		if (targs[i].completed == 0)
			continue;

		/*
		 * Collect threads output and extract information about
		 * how long it took to send all the packets.
		 */
		count += targs[i].count;
		if (!timerisset(&tic) || timercmp(&targs[i].tic, &tic, <))
			tic = targs[i].tic;
		if (!timerisset(&toc) || timercmp(&targs[i].toc, &toc, >))
			toc = targs[i].toc;
	}

	/* print output. */
	timersub(&toc, &tic, &toc);
	delta_t = toc.tv_sec + 1e-6* toc.tv_usec;
	if (td_body == sender_body)
		tx_output(count, g.pkt_size, delta_t);
	else
		rx_output(count, delta_t);
    }

    if (g.use_pcap == 0) {
	ioctl(fd, NIOCUNREGIF, &nmr);
	munmap(mmap_addr, nmr.nr_memsize);
	close(fd);
    }

	return (0);
}
/* end of file */