/*

 * Copyright (C) 2014 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.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <poll.h>

#include <ctype.h>

#include <errno.h>

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#define NETMAP_WITH_LIBS

#include <net/netmap_user.h>

#include "pcap-int.h"

#include "pcap-netmap.h"

#ifndef __FreeBSD__

  /*

   * On FreeBSD we use IFF_PPROMISC which is in ifr_flagshigh.

   * Remap to IFF_PROMISC on other platforms.

   *

   * XXX - DragonFly BSD?

   */

  #define IFF_PPROMISC	IFF_PROMISC

#endif /* __FreeBSD__ */

struct pcap_netmap {

	struct nm_desc *d;	/* pointer returned by nm_open() */

	pcap_handler cb;	/* callback and argument */

	u_char *cb_arg;

	int must_clear_promisc;	/* flag */

	uint64_t rx_pkts;	/* # of pkts received before the filter */

};

static int

pcap_netmap_stats(pcap_t *p, struct pcap_stat *ps)

{

	struct pcap_netmap *pn = p->priv;

	ps->ps_recv = (u_int)pn->rx_pkts;

	ps->ps_drop = 0;

	ps->ps_ifdrop = 0;

	return 0;

}

static void

pcap_netmap_filter(u_char *arg, struct pcap_pkthdr *h, const u_char *buf)

{

	pcap_t *p = (pcap_t *)arg;

	struct pcap_netmap *pn = p->priv;

	const struct bpf_insn *pc = p->fcode.bf_insns;

	++pn->rx_pkts;

	if (pc == NULL || bpf_filter(pc, buf, h->len, h->caplen))

		pn->cb(pn->cb_arg, h, buf);

}

static int

pcap_netmap_dispatch(pcap_t *p, int cnt, pcap_handler cb, u_char *user)

{

	int ret;

	struct pcap_netmap *pn = p->priv;

	struct nm_desc *d = pn->d;

	struct pollfd pfd = { .fd = p->fd, .events = POLLIN, .revents = 0 };

	pn->cb = cb;

	pn->cb_arg = user;

	for (;;) {

		if (p->break_loop) {

			p->break_loop = 0;

			return PCAP_ERROR_BREAK;

		}

		/* nm_dispatch won't run forever */

		ret = nm_dispatch((void *)d, cnt, (void *)pcap_netmap_filter, (void *)p);

		if (ret != 0)

			break;

		errno = 0;

		ret = poll(&pfd, 1, p->opt.timeout);

	}

	return ret;

}

/* XXX need to check the NIOCTXSYNC/poll */

static int

pcap_netmap_inject(pcap_t *p, const void *buf, size_t size)

{

	struct pcap_netmap *pn = p->priv;

	struct nm_desc *d = pn->d;

	return nm_inject(d, buf, size);

}

static int

pcap_netmap_ioctl(pcap_t *p, u_long what, uint32_t *if_flags)

{

	struct pcap_netmap *pn = p->priv;

	struct nm_desc *d = pn->d;

	struct ifreq ifr;

	int error, fd = d->fd;

#ifdef linux

	fd = socket(AF_INET, SOCK_DGRAM, 0);

	if (fd < 0) {

		fprintf(stderr, "Error: cannot get device control socket.\n");

		return -1;

	}

#endif /* linux */

	bzero(&ifr, sizeof(ifr));

	strncpy(ifr.ifr_name, d->req.nr_name, sizeof(ifr.ifr_name));

	switch (what) {

	case SIOCSIFFLAGS:

		/*

		 * The flags we pass in are 32-bit and unsigned.

		 *

		 * On most if not all UN*Xes, ifr_flags is 16-bit and

		 * signed, and the result of assigning a longer

		 * unsigned value to a shorter signed value is

		 * implementation-defined (even if, in practice, it'll

		 * do what's intended on all platforms we support

		 * result of assigning a 32-bit unsigned value).

		 * So we mask out the upper 16 bits.

		 */

		ifr.ifr_flags = *if_flags & 0xffff;

#ifdef __FreeBSD__

		/*

		 * In FreeBSD, we need to set the high-order flags,

		 * as we're using IFF_PPROMISC, which is in those bits.

		 *

		 * XXX - DragonFly BSD?

		 */

		ifr.ifr_flagshigh = *if_flags >> 16;

#endif /* __FreeBSD__ */

		break;

	}

	error = ioctl(fd, what, &ifr);

	if (!error) {

		switch (what) {

		case SIOCGIFFLAGS:

			/*

			 * The flags we return are 32-bit.

			 *

			 * On most if not all UN*Xes, ifr_flags is

			 * 16-bit and signed, and will get sign-

			 * extended, so that the upper 16 bits of

			 * those flags will be forced on.  So we

			 * mask out the upper 16 bits of the

			 * sign-extended value.

			 */

			*if_flags = ifr.ifr_flags & 0xffff;

#ifdef __FreeBSD__

			/*

			 * In FreeBSD, we need to return the

			 * high-order flags, as we're using

			 * IFF_PPROMISC, which is in those bits.

			 *

			 * XXX - DragonFly BSD?

			 */

			*if_flags |= (ifr.ifr_flagshigh << 16);

#endif /* __FreeBSD__ */

		}

	}

#ifdef linux

	close(fd);

#endif /* linux */

	return error ? -1 : 0;

}

static void

pcap_netmap_close(pcap_t *p)

{

	struct pcap_netmap *pn = p->priv;

	struct nm_desc *d = pn->d;

	uint32_t if_flags = 0;

	if (pn->must_clear_promisc) {

		pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */

		if (if_flags & IFF_PPROMISC) {

			if_flags &= ~IFF_PPROMISC;

			pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);

		}

	}

	nm_close(d);

	pcap_cleanup_live_common(p);

}

static int

pcap_netmap_activate(pcap_t *p)

{

	struct pcap_netmap *pn = p->priv;

	struct nm_desc *d;

	uint32_t if_flags = 0;

	d = nm_open(p->opt.device, NULL, 0, NULL);

	if (d == NULL) {

		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "netmap open: cannot access %s",

		    p->opt.device);

		pcap_cleanup_live_common(p);

		return (PCAP_ERROR);

	}

#if 0

	fprintf(stderr, "%s device %s priv %p fd %d ports %d..%d\n",

	    __FUNCTION__, p->opt.device, d, d->fd,

	    d->first_rx_ring, d->last_rx_ring);

#endif

	pn->d = d;

	p->fd = d->fd;

	/*

	 * Turn a negative snapshot value (invalid), a snapshot value of

	 * 0 (unspecified), or a value bigger than the normal maximum

	 * value, into the maximum allowed value.

	 *

	 * If some application really *needs* a bigger snapshot

	 * length, we should just increase MAXIMUM_SNAPLEN.

	 */

	if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)

		p->snapshot = MAXIMUM_SNAPLEN;

	if (p->opt.promisc && !(d->req.nr_ringid & NETMAP_SW_RING)) {

		pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */

		if (!(if_flags & IFF_PPROMISC)) {

			pn->must_clear_promisc = 1;

			if_flags |= IFF_PPROMISC;

			pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);

		}

	}

	p->linktype = DLT_EN10MB;

	p->selectable_fd = p->fd;

	p->read_op = pcap_netmap_dispatch;

	p->inject_op = pcap_netmap_inject;

	p->setfilter_op = install_bpf_program;

	p->setdirection_op = NULL;

	p->set_datalink_op = NULL;

	p->getnonblock_op = pcap_getnonblock_fd;

	p->setnonblock_op = pcap_setnonblock_fd;

	p->stats_op = pcap_netmap_stats;

	p->cleanup_op = pcap_netmap_close;

	return (0);

}

pcap_t *

pcap_netmap_create(const char *device, char *ebuf, int *is_ours)

{

	pcap_t *p;

	*is_ours = (!strncmp(device, "netmap:", 7) || !strncmp(device, "vale", 4));

	if (! *is_ours)

		return NULL;

	p = pcap_create_common(ebuf, sizeof (struct pcap_netmap));

	if (p == NULL)

		return (NULL);

	p->activate_op = pcap_netmap_activate;

	return (p);

}

/*

 * The "device name" for netmap devices isn't a name for a device, it's

 * an expression that indicates how the device should be set up, so

 * there's no way to enumerate them.

 */

int

pcap_netmap_findalldevs(pcap_if_list_t *devlistp _U_, char *err_str _U_)

{

	return 0;

}