xref: /freebsd/contrib/libpcap/pcap-rpcap.c (revision 924226fba12cc9a228c73b956e1b7fa24c60b055)

/*
 * Copyright (c) 2002 - 2005 NetGroup, Politecnico di Torino (Italy)
 * Copyright (c) 2005 - 2008 CACE Technologies, Davis (California)
 * 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.
 * 3. Neither the name of the Politecnico di Torino, CACE Technologies
 * nor the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 * OWNER 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 "ftmacros.h"

#include <string.h>		/* for strlen(), ... */
#include <stdlib.h>		/* for malloc(), free(), ... */
#include <stdarg.h>		/* for functions with variable number of arguments */
#include <errno.h>		/* for the errno variable */
#include "sockutils.h"
#include "pcap-int.h"
#include "rpcap-protocol.h"
#include "pcap-rpcap.h"

/*
 * This file contains the pcap module for capturing from a remote machine's
 * interfaces using the RPCAP protocol.
 *
 * WARNING: All the RPCAP functions that are allowed to return a buffer
 * containing the error description can return max PCAP_ERRBUF_SIZE characters.
 * However there is no guarantees that the string will be zero-terminated.
 * Best practice is to define the errbuf variable as a char of size
 * 'PCAP_ERRBUF_SIZE+1' and to insert manually a NULL character at the end
 * of the buffer. This will guarantee that no buffer overflows occur even
 * if we use the printf() to show the error on the screen.
 *
 * XXX - actually, null-terminating the error string is part of the
 * contract for the pcap API; if there's any place in the pcap code
 * that doesn't guarantee null-termination, even at the expense of
 * cutting the message short, that's a bug and needs to be fixed.
 */

#define PCAP_STATS_STANDARD	0	/* Used by pcap_stats_rpcap to see if we want standard or extended statistics */
#ifdef _WIN32
#define PCAP_STATS_EX		1	/* Used by pcap_stats_rpcap to see if we want standard or extended statistics */
#endif

/*
 * \brief Keeps a list of all the opened connections in the active mode.
 *
 * This structure defines a linked list of items that are needed to keep the info required to
 * manage the active mode.
 * In other words, when a new connection in active mode starts, this structure is updated so that
 * it reflects the list of active mode connections currently opened.
 * This structure is required by findalldevs() and open_remote() to see if they have to open a new
 * control connection toward the host, or they already have a control connection in place.
 */
struct activehosts
{
	struct sockaddr_storage host;
	SOCKET sockctrl;
	uint8 protocol_version;
	struct activehosts *next;
};

/* Keeps a list of all the opened connections in the active mode. */
static struct activehosts *activeHosts;

/*
 * Keeps the main socket identifier when we want to accept a new remote
 * connection (active mode only).
 * See the documentation of pcap_remoteact_accept() and
 * pcap_remoteact_cleanup() for more details.
 */
static SOCKET sockmain;

/*
 * Private data for capturing remotely using the rpcap protocol.
 */
struct pcap_rpcap {
	/*
	 * This is '1' if we're the network client; it is needed by several
	 * functions (such as pcap_setfilter()) to know whether they have
	 * to use the socket or have to open the local adapter.
	 */
	int rmt_clientside;

	SOCKET rmt_sockctrl;		/* socket ID of the socket used for the control connection */
	SOCKET rmt_sockdata;		/* socket ID of the socket used for the data connection */
	int rmt_flags;			/* we have to save flags, since they are passed by the pcap_open_live(), but they are used by the pcap_startcapture() */
	int rmt_capstarted;		/* 'true' if the capture is already started (needed to knoe if we have to call the pcap_startcapture() */
	char *currentfilter;		/* Pointer to a buffer (allocated at run-time) that stores the current filter. Needed when flag PCAP_OPENFLAG_NOCAPTURE_RPCAP is turned on. */

	uint8 protocol_version;		/* negotiated protocol version */

	unsigned int TotNetDrops;	/* keeps the number of packets that have been dropped by the network */

	/*
	 * This keeps the number of packets that have been received by the
	 * application.
	 *
	 * Packets dropped by the kernel buffer are not counted in this
	 * variable. It is always equal to (TotAccepted - TotDrops),
	 * except for the case of remote capture, in which we have also
	 * packets in flight, i.e. that have been transmitted by the remote
	 * host, but that have not been received (yet) from the client.
	 * In this case, (TotAccepted - TotDrops - TotNetDrops) gives a
	 * wrong result, since this number does not corresponds always to
	 * the number of packet received by the application. For this reason,
	 * in the remote capture we need another variable that takes into
	 * account of the number of packets actually received by the
	 * application.
	 */
	unsigned int TotCapt;

	struct pcap_stat stat;
	/* XXX */
	struct pcap *next;		/* list of open pcaps that need stuff cleared on close */
};

/****************************************************
 *                                                  *
 * Locally defined functions                        *
 *                                                  *
 ****************************************************/
static struct pcap_stat *rpcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps, int mode);
static int pcap_pack_bpffilter(pcap_t *fp, char *sendbuf, int *sendbufidx, struct bpf_program *prog);
static int pcap_createfilter_norpcappkt(pcap_t *fp, struct bpf_program *prog);
static int pcap_updatefilter_remote(pcap_t *fp, struct bpf_program *prog);
static void pcap_save_current_filter_rpcap(pcap_t *fp, const char *filter);
static int pcap_setfilter_rpcap(pcap_t *fp, struct bpf_program *prog);
static int pcap_setsampling_remote(pcap_t *fp);
static int pcap_startcapture_remote(pcap_t *fp);
static int rpcap_recv_msg_header(SOCKET sock, struct rpcap_header *header, char *errbuf);
static int rpcap_check_msg_ver(SOCKET sock, uint8 expected_ver, struct rpcap_header *header, char *errbuf);
static int rpcap_check_msg_type(SOCKET sock, uint8 request_type, struct rpcap_header *header, uint16 *errcode, char *errbuf);
static int rpcap_process_msg_header(SOCKET sock, uint8 ver, uint8 request_type, struct rpcap_header *header, char *errbuf);
static int rpcap_recv(SOCKET sock, void *buffer, size_t toread, uint32 *plen, char *errbuf);
static void rpcap_msg_err(SOCKET sockctrl, uint32 plen, char *remote_errbuf);
static int rpcap_discard(SOCKET sock, uint32 len, char *errbuf);
static int rpcap_read_packet_msg(SOCKET sock, pcap_t *p, size_t size);

/****************************************************
 *                                                  *
 * Function bodies                                  *
 *                                                  *
 ****************************************************/

/*
 * This function translates (i.e. de-serializes) a 'rpcap_sockaddr'
 * structure from the network byte order to a 'sockaddr_in" or
 * 'sockaddr_in6' structure in the host byte order.
 *
 * It accepts an 'rpcap_sockaddr' structure as it is received from the
 * network, and checks the address family field against various values
 * to see whether it looks like an IPv4 address, an IPv6 address, or
 * neither of those.  It checks for multiple values in order to try
 * to handle older rpcap daemons that sent the native OS's 'sockaddr_in'
 * or 'sockaddr_in6' structures over the wire with some members
 * byte-swapped, and to handle the fact that AF_INET6 has different
 * values on different OSes.
 *
 * For IPv4 addresses, it converts the address family to host byte
 * order from network byte order and puts it into the structure,
 * sets the length if a sockaddr structure has a length, converts the
 * port number to host byte order from network byte order and puts
 * it into the structure, copies over the IPv4 address, and zeroes
 * out the zero padding.
 *
 * For IPv6 addresses, it converts the address family to host byte
 * order from network byte order and puts it into the structure,
 * sets the length if a sockaddr structure has a length, converts the
 * port number and flow information to host byte order from network
 * byte order and puts them into the structure, copies over the IPv6
 * address, and converts the scope ID to host byte order from network
 * byte order and puts it into the structure.
 *
 * The function will allocate the 'sockaddrout' variable according to the
 * address family in use. In case the address does not belong to the
 * AF_INET nor AF_INET6 families, 'sockaddrout' is not allocated and a
 * NULL pointer is returned.  This usually happens because that address
 * does not exist on the other host, or is of an address family other
 * than AF_INET or AF_INET6, so the RPCAP daemon sent a 'sockaddr_storage'
 * structure containing all 'zero' values.
 *
 * Older RPCAPDs sent the addresses over the wire in the OS's native
 * structure format.  For most OSes, this looks like the over-the-wire
 * format, but might have a different value for AF_INET6 than the value
 * on the machine receiving the reply.  For OSes with the newer BSD-style
 * sockaddr structures, this has, instead of a 2-byte address family,
 * a 1-byte structure length followed by a 1-byte address family.  The
 * RPCAPD code would put the address family in network byte order before
 * sending it; that would set it to 0 on a little-endian machine, as
 * htons() of any value between 1 and 255 would result in a value > 255,
 * with its lower 8 bits zero, so putting that back into a 1-byte field
 * would set it to 0.
 *
 * Therefore, for older RPCAPDs running on an OS with newer BSD-style
 * sockaddr structures, the family field, if treated as a big-endian
 * (network byte order) 16-bit field, would be:
 *
 *	(length << 8) | family if sent by a big-endian machine
 *	(length << 8) if sent by a little-endian machine
 *
 * For current RPCAPDs, and for older RPCAPDs running on an OS with
 * older BSD-style sockaddr structures, the family field, if treated
 * as a big-endian 16-bit field, would just contain the family.
 *
 * \param sockaddrin: a 'rpcap_sockaddr' pointer to the variable that has
 * to be de-serialized.
 *
 * \param sockaddrout: a 'sockaddr_storage' pointer to the variable that will contain
 * the de-serialized data. The structure returned can be either a 'sockaddr_in' or 'sockaddr_in6'.
 * This variable will be allocated automatically inside this function.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size PCAP_ERRBUF_SIZE)
 * that will contain the error message (in case there is one).
 *
 * \return '0' if everything is fine, '-1' if some errors occurred. Basically, the error
 * can be only the fact that the malloc() failed to allocate memory.
 * The error message is returned in the 'errbuf' variable, while the deserialized address
 * is returned into the 'sockaddrout' variable.
 *
 * \warning This function supports only AF_INET and AF_INET6 address families.
 *
 * \warning The sockaddrout (if not NULL) must be deallocated by the user.
 */

/*
 * Possible IPv4 family values other than the designated over-the-wire value,
 * which is 2 (because everybody uses 2 for AF_INET4).
 */
#define SOCKADDR_IN_LEN		16	/* length of struct sockaddr_in */
#define SOCKADDR_IN6_LEN	28	/* length of struct sockaddr_in6 */
#define NEW_BSD_AF_INET_BE	((SOCKADDR_IN_LEN << 8) | 2)
#define NEW_BSD_AF_INET_LE	(SOCKADDR_IN_LEN << 8)

/*
 * Possible IPv6 family values other than the designated over-the-wire value,
 * which is 23 (because that's what Windows uses, and most RPCAP servers
 * out there are probably running Windows, as WinPcap includes the server
 * but few if any UN*Xes build and ship it).
 *
 * The new BSD sockaddr structure format was in place before 4.4-Lite, so
 * all the free-software BSDs use it.
 */
#define NEW_BSD_AF_INET6_BSD_BE		((SOCKADDR_IN6_LEN << 8) | 24)	/* NetBSD, OpenBSD, BSD/OS */
#define NEW_BSD_AF_INET6_FREEBSD_BE	((SOCKADDR_IN6_LEN << 8) | 28)	/* FreeBSD, DragonFly BSD */
#define NEW_BSD_AF_INET6_DARWIN_BE	((SOCKADDR_IN6_LEN << 8) | 30)	/* macOS, iOS, anything else Darwin-based */
#define NEW_BSD_AF_INET6_LE		(SOCKADDR_IN6_LEN << 8)
#define LINUX_AF_INET6			10
#define HPUX_AF_INET6			22
#define AIX_AF_INET6			24
#define SOLARIS_AF_INET6		26

static int
rpcap_deseraddr(struct rpcap_sockaddr *sockaddrin, struct sockaddr_storage **sockaddrout, char *errbuf)
{
	/* Warning: we support only AF_INET and AF_INET6 */
	switch (ntohs(sockaddrin->family))
	{
	case RPCAP_AF_INET:
	case NEW_BSD_AF_INET_BE:
	case NEW_BSD_AF_INET_LE:
		{
		struct rpcap_sockaddr_in *sockaddrin_ipv4;
		struct sockaddr_in *sockaddrout_ipv4;

		(*sockaddrout) = (struct sockaddr_storage *) malloc(sizeof(struct sockaddr_in));
		if ((*sockaddrout) == NULL)
		{
			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
			    errno, "malloc() failed");
			return -1;
		}
		sockaddrin_ipv4 = (struct rpcap_sockaddr_in *) sockaddrin;
		sockaddrout_ipv4 = (struct sockaddr_in *) (*sockaddrout);
		sockaddrout_ipv4->sin_family = AF_INET;
		sockaddrout_ipv4->sin_port = ntohs(sockaddrin_ipv4->port);
		memcpy(&sockaddrout_ipv4->sin_addr, &sockaddrin_ipv4->addr, sizeof(sockaddrout_ipv4->sin_addr));
		memset(sockaddrout_ipv4->sin_zero, 0, sizeof(sockaddrout_ipv4->sin_zero));
		break;
		}

#ifdef AF_INET6
	case RPCAP_AF_INET6:
	case NEW_BSD_AF_INET6_BSD_BE:
	case NEW_BSD_AF_INET6_FREEBSD_BE:
	case NEW_BSD_AF_INET6_DARWIN_BE:
	case NEW_BSD_AF_INET6_LE:
	case LINUX_AF_INET6:
	case HPUX_AF_INET6:
	case AIX_AF_INET6:
	case SOLARIS_AF_INET6:
		{
		struct rpcap_sockaddr_in6 *sockaddrin_ipv6;
		struct sockaddr_in6 *sockaddrout_ipv6;

		(*sockaddrout) = (struct sockaddr_storage *) malloc(sizeof(struct sockaddr_in6));
		if ((*sockaddrout) == NULL)
		{
			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
			    errno, "malloc() failed");
			return -1;
		}
		sockaddrin_ipv6 = (struct rpcap_sockaddr_in6 *) sockaddrin;
		sockaddrout_ipv6 = (struct sockaddr_in6 *) (*sockaddrout);
		sockaddrout_ipv6->sin6_family = AF_INET6;
		sockaddrout_ipv6->sin6_port = ntohs(sockaddrin_ipv6->port);
		sockaddrout_ipv6->sin6_flowinfo = ntohl(sockaddrin_ipv6->flowinfo);
		memcpy(&sockaddrout_ipv6->sin6_addr, &sockaddrin_ipv6->addr, sizeof(sockaddrout_ipv6->sin6_addr));
		sockaddrout_ipv6->sin6_scope_id = ntohl(sockaddrin_ipv6->scope_id);
		break;
		}
#endif

	default:
		/*
		 * It is neither AF_INET nor AF_INET6 (or, if the OS doesn't
		 * support AF_INET6, it's not AF_INET).
		 */
		*sockaddrout = NULL;
		break;
	}
	return 0;
}

/*
 * This function reads a packet from the network socket.  It does not
 * deliver the packet to a pcap_dispatch()/pcap_loop() callback (hence
 * the "nocb" string into its name).
 *
 * This function is called by pcap_read_rpcap().
 *
 * WARNING: By choice, this function does not make use of semaphores. A smarter
 * implementation should put a semaphore into the data thread, and a signal will
 * be raised as soon as there is data into the socket buffer.
 * However this is complicated and it does not bring any advantages when reading
 * from the network, in which network delays can be much more important than
 * these optimizations. Therefore, we chose the following approach:
 * - the 'timeout' chosen by the user is split in two (half on the server side,
 * with the usual meaning, and half on the client side)
 * - this function checks for packets; if there are no packets, it waits for
 * timeout/2 and then it checks again. If packets are still missing, it returns,
 * otherwise it reads packets.
 */
static int pcap_read_nocb_remote(pcap_t *p, struct pcap_pkthdr *pkt_header, u_char **pkt_data)
{
	struct pcap_rpcap *pr = p->priv;	/* structure used when doing a remote live capture */
	struct rpcap_header *header;		/* general header according to the RPCAP format */
	struct rpcap_pkthdr *net_pkt_header;	/* header of the packet, from the message */
	u_char *net_pkt_data;			/* packet data from the message */
	uint32 plen;
	int retval;				/* generic return value */
	int msglen;

	/* Structures needed for the select() call */
	struct timeval tv;			/* maximum time the select() can block waiting for data */
	fd_set rfds;				/* set of socket descriptors we have to check */

	/*
	 * Define the packet buffer timeout, to be used in the select()
	 * 'timeout', in pcap_t, is in milliseconds; we have to convert it into sec and microsec
	 */
	tv.tv_sec = p->opt.timeout / 1000;
	tv.tv_usec = (p->opt.timeout - tv.tv_sec * 1000) * 1000;

	/* Watch out sockdata to see if it has input */
	FD_ZERO(&rfds);

	/*
	 * 'fp->rmt_sockdata' has always to be set before calling the select(),
	 * since it is cleared by the select()
	 */
	FD_SET(pr->rmt_sockdata, &rfds);

	retval = select((int) pr->rmt_sockdata + 1, &rfds, NULL, NULL, &tv);
	if (retval == -1)
	{
#ifndef _WIN32
		if (errno == EINTR)
		{
			/* Interrupted. */
			return 0;
		}
#endif
		sock_geterror("select()", p->errbuf, PCAP_ERRBUF_SIZE);
		return -1;
	}

	/* There is no data waiting, so return '0' */
	if (retval == 0)
		return 0;

	/*
	 * We have to define 'header' as a pointer to a larger buffer,
	 * because in case of UDP we have to read all the message within a single call
	 */
	header = (struct rpcap_header *) p->buffer;
	net_pkt_header = (struct rpcap_pkthdr *) ((char *)p->buffer + sizeof(struct rpcap_header));
	net_pkt_data = (u_char *)p->buffer + sizeof(struct rpcap_header) + sizeof(struct rpcap_pkthdr);

	if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
	{
		/* Read the entire message from the network */
		msglen = sock_recv_dgram(pr->rmt_sockdata, p->buffer,
		    p->bufsize, p->errbuf, PCAP_ERRBUF_SIZE);
		if (msglen == -1)
		{
			/* Network error. */
			return -1;
		}
		if (msglen == -3)
		{
			/* Interrupted receive. */
			return 0;
		}
		if ((size_t)msglen < sizeof(struct rpcap_header))
		{
			/*
			 * Message is shorter than an rpcap header.
			 */
			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
			    "UDP packet message is shorter than an rpcap header");
			return -1;
		}
		plen = ntohl(header->plen);
		if ((size_t)msglen < sizeof(struct rpcap_header) + plen)
		{
			/*
			 * Message is shorter than the header claims it
			 * is.
			 */
			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
			    "UDP packet message is shorter than its rpcap header claims");
			return -1;
		}
	}
	else
	{
		int status;

		if ((size_t)p->cc < sizeof(struct rpcap_header))
		{
			/*
			 * We haven't read any of the packet header yet.
			 * The size we should get is the size of the
			 * packet header.
			 */
			status = rpcap_read_packet_msg(pr->rmt_sockdata, p,
			    sizeof(struct rpcap_header));
			if (status == -1)
			{
				/* Network error. */
				return -1;
			}
			if (status == -3)
			{
				/* Interrupted receive. */
				return 0;
			}
		}

		/*
		 * We have the header, so we know how long the
		 * message payload is.  The size we should get
		 * is the size of the packet header plus the
		 * size of the payload.
		 */
		plen = ntohl(header->plen);
		if (plen > p->bufsize - sizeof(struct rpcap_header))
		{
			/*
			 * This is bigger than the largest
			 * record we'd expect.  (We do it by
			 * subtracting in order to avoid an
			 * overflow.)
			 */
			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
			    "Server sent us a message larger than the largest expected packet message");
			return -1;
		}
		status = rpcap_read_packet_msg(pr->rmt_sockdata, p,
		    sizeof(struct rpcap_header) + plen);
		if (status == -1)
		{
			/* Network error. */
			return -1;
		}
		if (status == -3)
		{
			/* Interrupted receive. */
			return 0;
		}

		/*
		 * We have the entire message; reset the buffer pointer
		 * and count, as the next read should start a new
		 * message.
		 */
		p->bp = p->buffer;
		p->cc = 0;
	}

	/*
	 * We have the entire message.
	 */
	header->plen = plen;

	/*
	 * Did the server specify the version we negotiated?
	 */
	if (rpcap_check_msg_ver(pr->rmt_sockdata, pr->protocol_version,
	    header, p->errbuf) == -1)
	{
		return 0;	/* Return 'no packets received' */
	}

	/*
	 * Is this a RPCAP_MSG_PACKET message?
	 */
	if (header->type != RPCAP_MSG_PACKET)
	{
		return 0;	/* Return 'no packets received' */
	}

	if (ntohl(net_pkt_header->caplen) > plen)
	{
		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
		    "Packet's captured data goes past the end of the received packet message.");
		return -1;
	}

	/* Fill in packet header */
	pkt_header->caplen = ntohl(net_pkt_header->caplen);
	pkt_header->len = ntohl(net_pkt_header->len);
	pkt_header->ts.tv_sec = ntohl(net_pkt_header->timestamp_sec);
	pkt_header->ts.tv_usec = ntohl(net_pkt_header->timestamp_usec);

	/* Supply a pointer to the beginning of the packet data */
	*pkt_data = net_pkt_data;

	/*
	 * I don't update the counter of the packets dropped by the network since we're using TCP,
	 * therefore no packets are dropped. Just update the number of packets received correctly
	 */
	pr->TotCapt++;

	if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
	{
		unsigned int npkt;

		/* We're using UDP, so we need to update the counter of the packets dropped by the network */
		npkt = ntohl(net_pkt_header->npkt);

		if (pr->TotCapt != npkt)
		{
			pr->TotNetDrops += (npkt - pr->TotCapt);
			pr->TotCapt = npkt;
		}
	}

	/* Packet read successfully */
	return 1;
}

/*
 * This function reads a packet from the network socket.
 *
 * This function relies on the pcap_read_nocb_remote to deliver packets. The
 * difference, here, is that as soon as a packet is read, it is delivered
 * to the application by means of a callback function.
 */
static int pcap_read_rpcap(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
	struct pcap_rpcap *pr = p->priv;	/* structure used when doing a remote live capture */
	struct pcap_pkthdr pkt_header;
	u_char *pkt_data;
	int n = 0;
	int ret;

	/*
	 * If this is client-side, and we haven't already started
	 * the capture, start it now.
	 */
	if (pr->rmt_clientside)
	{
		/* We are on an remote capture */
		if (!pr->rmt_capstarted)
		{
			/*
			 * The capture isn't started yet, so try to
			 * start it.
			 */
			if (pcap_startcapture_remote(p))
				return -1;
		}
	}

	while (n < cnt || PACKET_COUNT_IS_UNLIMITED(cnt))
	{
		/*
		 * Has "pcap_breakloop()" been called?
		 */
		if (p->break_loop) {
			/*
			 * Yes - clear the flag that indicates that it
			 * has, and return PCAP_ERROR_BREAK to indicate
			 * that we were told to break out of the loop.
			 */
			p->break_loop = 0;
			return (PCAP_ERROR_BREAK);
		}

		/*
		 * Read some packets.
		 */
		ret = pcap_read_nocb_remote(p, &pkt_header, &pkt_data);
		if (ret == 1)
		{
			/*
			 * We got a packet.  Hand it to the callback
			 * and count it so we can return the count.
			 */
			(*callback)(user, &pkt_header, pkt_data);
			n++;
		}
		else if (ret == -1)
		{
			/* Error. */
			return ret;
		}
		else
		{
			/*
			 * No packet; this could mean that we timed
			 * out, or that we got interrupted, or that
			 * we got a bad packet.
			 *
			 * Were we told to break out of the loop?
			 */
			if (p->break_loop) {
				/*
				 * Yes.
				 */
				p->break_loop = 0;
				return (PCAP_ERROR_BREAK);
			}
			/* No - return the number of packets we've processed. */
			return n;
		}
	}
	return n;
}

/*
 * This function sends a CLOSE command to the capture server.
 *
 * It is called when the user calls pcap_close().  It sends a command
 * to our peer that says 'ok, let's stop capturing'.
 *
 * WARNING: Since we're closing the connection, we do not check for errors.
 */
static void pcap_cleanup_rpcap(pcap_t *fp)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */
	struct rpcap_header header;		/* header of the RPCAP packet */
	struct activehosts *temp;		/* temp var needed to scan the host list chain, to detect if we're in active mode */
	int active = 0;				/* active mode or not? */

	/* detect if we're in active mode */
	temp = activeHosts;
	while (temp)
	{
		if (temp->sockctrl == pr->rmt_sockctrl)
		{
			active = 1;
			break;
		}
		temp = temp->next;
	}

	if (!active)
	{
		rpcap_createhdr(&header, pr->protocol_version,
		    RPCAP_MSG_CLOSE, 0, 0);

		/*
		 * Send the close request; don't report any errors, as
		 * we're closing this pcap_t, and have no place to report
		 * the error.  No reply is sent to this message.
		 */
		(void)sock_send(pr->rmt_sockctrl, (char *)&header,
		    sizeof(struct rpcap_header), NULL, 0);
	}
	else
	{
		rpcap_createhdr(&header, pr->protocol_version,
		    RPCAP_MSG_ENDCAP_REQ, 0, 0);

		/*
		 * Send the end capture request; don't report any errors,
		 * as we're closing this pcap_t, and have no place to
		 * report the error.
		 */
		if (sock_send(pr->rmt_sockctrl, (char *)&header,
		    sizeof(struct rpcap_header), NULL, 0) == 0)
		{
			/*
			 * Wait for the answer; don't report any errors,
			 * as we're closing this pcap_t, and have no
			 * place to report the error.
			 */
			if (rpcap_process_msg_header(pr->rmt_sockctrl,
			    pr->protocol_version, RPCAP_MSG_ENDCAP_REQ,
			    &header, NULL) == 0)
			{
				(void)rpcap_discard(pr->rmt_sockctrl,
				    header.plen, NULL);
			}
		}
	}

	if (pr->rmt_sockdata)
	{
		sock_close(pr->rmt_sockdata, NULL, 0);
		pr->rmt_sockdata = 0;
	}

	if ((!active) && (pr->rmt_sockctrl))
		sock_close(pr->rmt_sockctrl, NULL, 0);

	pr->rmt_sockctrl = 0;

	if (pr->currentfilter)
	{
		free(pr->currentfilter);
		pr->currentfilter = NULL;
	}

	pcap_cleanup_live_common(fp);

	/* To avoid inconsistencies in the number of sock_init() */
	sock_cleanup();
}

/*
 * This function retrieves network statistics from our peer;
 * it provides only the standard statistics.
 */
static int pcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps)
{
	struct pcap_stat *retval;

	retval = rpcap_stats_rpcap(p, ps, PCAP_STATS_STANDARD);

	if (retval)
		return 0;
	else
		return -1;
}

#ifdef _WIN32
/*
 * This function retrieves network statistics from our peer;
 * it provides the additional statistics supported by pcap_stats_ex().
 */
static struct pcap_stat *pcap_stats_ex_rpcap(pcap_t *p, int *pcap_stat_size)
{
	*pcap_stat_size = sizeof (p->stat);

	/* PCAP_STATS_EX (third param) means 'extended pcap_stats()' */
	return (rpcap_stats_rpcap(p, &(p->stat), PCAP_STATS_EX));
}
#endif

/*
 * This function retrieves network statistics from our peer.  It
 * is used by the two previous functions.
 *
 * It can be called in two modes:
 * - PCAP_STATS_STANDARD: if we want just standard statistics (i.e.,
 *   for pcap_stats())
 * - PCAP_STATS_EX: if we want extended statistics (i.e., for
 *   pcap_stats_ex())
 *
 * This 'mode' parameter is needed because in pcap_stats() the variable that
 * keeps the statistics is allocated by the user. On Windows, this structure
 * has been extended in order to keep new stats. However, if the user has a
 * smaller structure and it passes it to pcap_stats(), this function will
 * try to fill in more data than the size of the structure, so that memory
 * after the structure will be overwritten.
 *
 * So, we need to know it we have to copy just the standard fields, or the
 * extended fields as well.
 *
 * In case we want to copy the extended fields as well, the problem of
 * memory overflow no longer exists because the structure that's filled
 * in is part of the pcap_t, so that it can be guaranteed to be large
 * enough for the additional statistics.
 *
 * \param p: the pcap_t structure related to the current instance.
 *
 * \param ps: a pointer to a 'pcap_stat' structure, needed for compatibility
 * with pcap_stat(), where the structure is allocated by the user. In case
 * of pcap_stats_ex(), this structure and the function return value point
 * to the same variable.
 *
 * \param mode: one of PCAP_STATS_STANDARD or PCAP_STATS_EX.
 *
 * \return The structure that keeps the statistics, or NULL in case of error.
 * The error string is placed in the pcap_t structure.
 */
static struct pcap_stat *rpcap_stats_rpcap(pcap_t *p, struct pcap_stat *ps, int mode)
{
	struct pcap_rpcap *pr = p->priv;	/* structure used when doing a remote live capture */
	struct rpcap_header header;		/* header of the RPCAP packet */
	struct rpcap_stats netstats;		/* statistics sent on the network */
	uint32 plen;				/* data remaining in the message */

#ifdef _WIN32
	if (mode != PCAP_STATS_STANDARD && mode != PCAP_STATS_EX)
#else
	if (mode != PCAP_STATS_STANDARD)
#endif
	{
		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
		    "Invalid stats mode %d", mode);
		return NULL;
	}

	/*
	 * If the capture has not yet started, we cannot request statistics
	 * for the capture from our peer, so we return 0 for all statistics,
	 * as nothing's been seen yet.
	 */
	if (!pr->rmt_capstarted)
	{
		ps->ps_drop = 0;
		ps->ps_ifdrop = 0;
		ps->ps_recv = 0;
#ifdef _WIN32
		if (mode == PCAP_STATS_EX)
		{
			ps->ps_capt = 0;
			ps->ps_sent = 0;
			ps->ps_netdrop = 0;
		}
#endif /* _WIN32 */

		return ps;
	}

	rpcap_createhdr(&header, pr->protocol_version,
	    RPCAP_MSG_STATS_REQ, 0, 0);

	/* Send the PCAP_STATS command */
	if (sock_send(pr->rmt_sockctrl, (char *)&header,
	    sizeof(struct rpcap_header), p->errbuf, PCAP_ERRBUF_SIZE) < 0)
		return NULL;		/* Unrecoverable network error */

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
	    RPCAP_MSG_STATS_REQ, &header, p->errbuf) == -1)
		return NULL;		/* Error */

	plen = header.plen;

	/* Read the reply body */
	if (rpcap_recv(pr->rmt_sockctrl, (char *)&netstats,
	    sizeof(struct rpcap_stats), &plen, p->errbuf) == -1)
		goto error;

	ps->ps_drop = ntohl(netstats.krnldrop);
	ps->ps_ifdrop = ntohl(netstats.ifdrop);
	ps->ps_recv = ntohl(netstats.ifrecv);
#ifdef _WIN32
	if (mode == PCAP_STATS_EX)
	{
		ps->ps_capt = pr->TotCapt;
		ps->ps_netdrop = pr->TotNetDrops;
		ps->ps_sent = ntohl(netstats.svrcapt);
	}
#endif /* _WIN32 */

	/* Discard the rest of the message. */
	if (rpcap_discard(pr->rmt_sockctrl, plen, p->errbuf) == -1)
		goto error_nodiscard;

	return ps;

error:
	/*
	 * Discard the rest of the message.
	 * We already reported an error; if this gets an error, just
	 * drive on.
	 */
	(void)rpcap_discard(pr->rmt_sockctrl, plen, NULL);

error_nodiscard:
	return NULL;
}

/*
 * This function returns the entry in the list of active hosts for this
 * active connection (active mode only), or NULL if there is no
 * active connection or an error occurred.  It is just for internal
 * use.
 *
 * \param host: a string that keeps the host name of the host for which we
 * want to get the socket ID for that active connection.
 *
 * \param error: a pointer to an int that is set to 1 if an error occurred
 * and 0 otherwise.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size
 * PCAP_ERRBUF_SIZE) that will contain the error message (in case
 * there is one).
 *
 * \return the entry for this host in the list of active connections
 * if found, NULL if it's not found or there's an error.
 */
static struct activehosts *
rpcap_remoteact_getsock(const char *host, int *error, char *errbuf)
{
	struct activehosts *temp;			/* temp var needed to scan the host list chain */
	struct addrinfo hints, *addrinfo, *ai_next;	/* temp var needed to translate between hostname to its address */
	int retval;

	/* retrieve the network address corresponding to 'host' */
	addrinfo = NULL;
	memset(&hints, 0, sizeof(struct addrinfo));
	hints.ai_family = PF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;

	retval = getaddrinfo(host, "0", &hints, &addrinfo);
	if (retval != 0)
	{
		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "getaddrinfo() %s",
		    gai_strerror(retval));
		*error = 1;
		return NULL;
	}

	temp = activeHosts;

	while (temp)
	{
		ai_next = addrinfo;
		while (ai_next)
		{
			if (sock_cmpaddr(&temp->host, (struct sockaddr_storage *) ai_next->ai_addr) == 0)
			{
				*error = 0;
				freeaddrinfo(addrinfo);
				return temp;
			}

			ai_next = ai_next->ai_next;
		}
		temp = temp->next;
	}

	if (addrinfo)
		freeaddrinfo(addrinfo);

	/*
	 * The host for which you want to get the socket ID does not have an
	 * active connection.
	 */
	*error = 0;
	return NULL;
}

/*
 * This function starts a remote capture.
 *
 * This function is required since the RPCAP protocol decouples the 'open'
 * from the 'start capture' functions.
 * This function takes all the parameters needed (which have been stored
 * into the pcap_t structure) and sends them to the server.
 *
 * \param fp: the pcap_t descriptor of the device currently open.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message
 * (if one) is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_startcapture_remote(pcap_t *fp)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */
	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data to be sent is buffered */
	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
	char portdata[PCAP_BUF_SIZE];		/* temp variable needed to keep the network port for the data connection */
	uint32 plen;
	int active = 0;				/* '1' if we're in active mode */
	struct activehosts *temp;		/* temp var needed to scan the host list chain, to detect if we're in active mode */
	char host[INET6_ADDRSTRLEN + 1];	/* numeric name of the other host */

	/* socket-related variables*/
	struct addrinfo hints;			/* temp, needed to open a socket connection */
	struct addrinfo *addrinfo;		/* temp, needed to open a socket connection */
	SOCKET sockdata = 0;			/* socket descriptor of the data connection */
	struct sockaddr_storage saddr;		/* temp, needed to retrieve the network data port chosen on the local machine */
	socklen_t saddrlen;			/* temp, needed to retrieve the network data port chosen on the local machine */
	int ai_family;				/* temp, keeps the address family used by the control connection */

	/* RPCAP-related variables*/
	struct rpcap_header header;			/* header of the RPCAP packet */
	struct rpcap_startcapreq *startcapreq;		/* start capture request message */
	struct rpcap_startcapreply startcapreply;	/* start capture reply message */

	/* Variables related to the buffer setting */
	int res;
	socklen_t itemp;
	int sockbufsize = 0;
	uint32 server_sockbufsize;

	/*
	 * Let's check if sampling has been required.
	 * If so, let's set it first
	 */
	if (pcap_setsampling_remote(fp) != 0)
		return -1;

	/* detect if we're in active mode */
	temp = activeHosts;
	while (temp)
	{
		if (temp->sockctrl == pr->rmt_sockctrl)
		{
			active = 1;
			break;
		}
		temp = temp->next;
	}

	addrinfo = NULL;

	/*
	 * Gets the complete sockaddr structure used in the ctrl connection
	 * This is needed to get the address family of the control socket
	 * Tip: I cannot save the ai_family of the ctrl sock in the pcap_t struct,
	 * since the ctrl socket can already be open in case of active mode;
	 * so I would have to call getpeername() anyway
	 */
	saddrlen = sizeof(struct sockaddr_storage);
	if (getpeername(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
	{
		sock_geterror("getsockname()", fp->errbuf, PCAP_ERRBUF_SIZE);
		goto error_nodiscard;
	}
	ai_family = ((struct sockaddr_storage *) &saddr)->ss_family;

	/* Get the numeric address of the remote host we are connected to */
	if (getnameinfo((struct sockaddr *) &saddr, saddrlen, host,
		sizeof(host), NULL, 0, NI_NUMERICHOST))
	{
		sock_geterror("getnameinfo()", fp->errbuf, PCAP_ERRBUF_SIZE);
		goto error_nodiscard;
	}

	/*
	 * Data connection is opened by the server toward the client if:
	 * - we're using TCP, and the user wants us to be in active mode
	 * - we're using UDP
	 */
	if ((active) || (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
	{
		/*
		 * We have to create a new socket to receive packets
		 * We have to do that immediately, since we have to tell the other
		 * end which network port we picked up
		 */
		memset(&hints, 0, sizeof(struct addrinfo));
		/* TEMP addrinfo is NULL in case of active */
		hints.ai_family = ai_family;	/* Use the same address family of the control socket */
		hints.ai_socktype = (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP) ? SOCK_DGRAM : SOCK_STREAM;
		hints.ai_flags = AI_PASSIVE;	/* Data connection is opened by the server toward the client */

		/* Let's the server pick up a free network port for us */
		if (sock_initaddress(NULL, "0", &hints, &addrinfo, fp->errbuf, PCAP_ERRBUF_SIZE) == -1)
			goto error_nodiscard;

		if ((sockdata = sock_open(addrinfo, SOCKOPEN_SERVER,
			1 /* max 1 connection in queue */, fp->errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
			goto error_nodiscard;

		/* addrinfo is no longer used */
		freeaddrinfo(addrinfo);
		addrinfo = NULL;

		/* get the complete sockaddr structure used in the data connection */
		saddrlen = sizeof(struct sockaddr_storage);
		if (getsockname(sockdata, (struct sockaddr *) &saddr, &saddrlen) == -1)
		{
			sock_geterror("getsockname()", fp->errbuf, PCAP_ERRBUF_SIZE);
			goto error_nodiscard;
		}

		/* Get the local port the system picked up */
		if (getnameinfo((struct sockaddr *) &saddr, saddrlen, NULL,
			0, portdata, sizeof(portdata), NI_NUMERICSERV))
		{
			sock_geterror("getnameinfo()", fp->errbuf, PCAP_ERRBUF_SIZE);
			goto error_nodiscard;
		}
	}

	/*
	 * Now it's time to start playing with the RPCAP protocol
	 * RPCAP start capture command: create the request message
	 */
	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		goto error_nodiscard;

	rpcap_createhdr((struct rpcap_header *) sendbuf,
	    pr->protocol_version, RPCAP_MSG_STARTCAP_REQ, 0,
	    sizeof(struct rpcap_startcapreq) + sizeof(struct rpcap_filter) + fp->fcode.bf_len * sizeof(struct rpcap_filterbpf_insn));

	/* Fill the structure needed to open an adapter remotely */
	startcapreq = (struct rpcap_startcapreq *) &sendbuf[sendbufidx];

	if (sock_bufferize(NULL, sizeof(struct rpcap_startcapreq), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		goto error_nodiscard;

	memset(startcapreq, 0, sizeof(struct rpcap_startcapreq));

	/* By default, apply half the timeout on one side, half of the other */
	fp->opt.timeout = fp->opt.timeout / 2;
	startcapreq->read_timeout = htonl(fp->opt.timeout);

	/* portdata on the openreq is meaningful only if we're in active mode */
	if ((active) || (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
	{
		sscanf(portdata, "%d", (int *)&(startcapreq->portdata));	/* cast to avoid a compiler warning */
		startcapreq->portdata = htons(startcapreq->portdata);
	}

	startcapreq->snaplen = htonl(fp->snapshot);
	startcapreq->flags = 0;

	if (pr->rmt_flags & PCAP_OPENFLAG_PROMISCUOUS)
		startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_PROMISC;
	if (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP)
		startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_DGRAM;
	if (active)
		startcapreq->flags |= RPCAP_STARTCAPREQ_FLAG_SERVEROPEN;

	startcapreq->flags = htons(startcapreq->flags);

	/* Pack the capture filter */
	if (pcap_pack_bpffilter(fp, &sendbuf[sendbufidx], &sendbufidx, &fp->fcode))
		goto error_nodiscard;

	if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
	    PCAP_ERRBUF_SIZE) < 0)
		goto error_nodiscard;

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
	    RPCAP_MSG_STARTCAP_REQ, &header, fp->errbuf) == -1)
		goto error_nodiscard;

	plen = header.plen;

	if (rpcap_recv(pr->rmt_sockctrl, (char *)&startcapreply,
	    sizeof(struct rpcap_startcapreply), &plen, fp->errbuf) == -1)
		goto error;

	/*
	 * In case of UDP data stream, the connection is always opened by the daemon
	 * So, this case is already covered by the code above.
	 * Now, we have still to handle TCP connections, because:
	 * - if we're in active mode, we have to wait for a remote connection
	 * - if we're in passive more, we have to start a connection
	 *
	 * We have to do he job in two steps because in case we're opening a TCP connection, we have
	 * to tell the port we're using to the remote side; in case we're accepting a TCP
	 * connection, we have to wait this info from the remote side.
	 */
	if (!(pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP))
	{
		if (!active)
		{
			memset(&hints, 0, sizeof(struct addrinfo));
			hints.ai_family = ai_family;		/* Use the same address family of the control socket */
			hints.ai_socktype = (pr->rmt_flags & PCAP_OPENFLAG_DATATX_UDP) ? SOCK_DGRAM : SOCK_STREAM;
			pcap_snprintf(portdata, PCAP_BUF_SIZE, "%d", ntohs(startcapreply.portdata));

			/* Let's the server pick up a free network port for us */
			if (sock_initaddress(host, portdata, &hints, &addrinfo, fp->errbuf, PCAP_ERRBUF_SIZE) == -1)
				goto error;

			if ((sockdata = sock_open(addrinfo, SOCKOPEN_CLIENT, 0, fp->errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
				goto error;

			/* addrinfo is no longer used */
			freeaddrinfo(addrinfo);
			addrinfo = NULL;
		}
		else
		{
			SOCKET socktemp;	/* We need another socket, since we're going to accept() a connection */

			/* Connection creation */
			saddrlen = sizeof(struct sockaddr_storage);

			socktemp = accept(sockdata, (struct sockaddr *) &saddr, &saddrlen);

			if (socktemp == INVALID_SOCKET)
			{
				sock_geterror("accept()", fp->errbuf, PCAP_ERRBUF_SIZE);
				goto error;
			}

			/* Now that I accepted the connection, the server socket is no longer needed */
			sock_close(sockdata, fp->errbuf, PCAP_ERRBUF_SIZE);
			sockdata = socktemp;
		}
	}

	/* Let's save the socket of the data connection */
	pr->rmt_sockdata = sockdata;

	/*
	 * Set the size of the socket buffer for the data socket.
	 * It has the same size as the local capture buffer used
	 * on the other side of the connection.
	 */
	server_sockbufsize = ntohl(startcapreply.bufsize);

	/* Let's get the actual size of the socket buffer */
	itemp = sizeof(sockbufsize);

	res = getsockopt(sockdata, SOL_SOCKET, SO_RCVBUF, (char *)&sockbufsize, &itemp);
	if (res == -1)
	{
		sock_geterror("pcap_startcapture_remote(): getsockopt() failed", fp->errbuf, PCAP_ERRBUF_SIZE);
		goto error;
	}

	/*
	 * Warning: on some kernels (e.g. Linux), the size of the user
	 * buffer does not take into account the pcap_header and such,
	 * and it is set equal to the snaplen.
	 *
	 * In my view, this is wrong (the meaning of the bufsize became
	 * a bit strange).  So, here bufsize is the whole size of the
	 * user buffer.  In case the bufsize returned is too small,
	 * let's adjust it accordingly.
	 */
	if (server_sockbufsize <= (u_int) fp->snapshot)
		server_sockbufsize += sizeof(struct pcap_pkthdr);

	/* if the current socket buffer is smaller than the desired one */
	if ((u_int) sockbufsize < server_sockbufsize)
	{
		/*
		 * Loop until the buffer size is OK or the original
		 * socket buffer size is larger than this one.
		 */
		for (;;)
		{
			res = setsockopt(sockdata, SOL_SOCKET, SO_RCVBUF,
			    (char *)&(server_sockbufsize),
			    sizeof(server_sockbufsize));

			if (res == 0)
				break;

			/*
			 * If something goes wrong, halve the buffer size
			 * (checking that it does not become smaller than
			 * the current one).
			 */
			server_sockbufsize /= 2;

			if ((u_int) sockbufsize >= server_sockbufsize)
			{
				server_sockbufsize = sockbufsize;
				break;
			}
		}
	}

	/*
	 * Let's allocate the packet; this is required in order to put
	 * the packet somewhere when extracting data from the socket.
	 * Since buffering has already been done in the socket buffer,
	 * here we need just a buffer whose size is equal to the
	 * largest possible packet message for the snapshot size,
	 * namely the length of the message header plus the length
	 * of the packet header plus the snapshot length.
	 */
	fp->bufsize = sizeof(struct rpcap_header) + sizeof(struct rpcap_pkthdr) + fp->snapshot;

	fp->buffer = (u_char *)malloc(fp->bufsize);
	if (fp->buffer == NULL)
	{
		pcap_fmt_errmsg_for_errno(fp->errbuf, PCAP_ERRBUF_SIZE,
		    errno, "malloc");
		goto error;
	}

	/*
	 * The buffer is currently empty.
	 */
	fp->bp = fp->buffer;
	fp->cc = 0;

	/* Discard the rest of the message. */
	if (rpcap_discard(pr->rmt_sockctrl, plen, fp->errbuf) == -1)
		goto error_nodiscard;

	/*
	 * In case the user does not want to capture RPCAP packets, let's update the filter
	 * We have to update it here (instead of sending it into the 'StartCapture' message
	 * because when we generate the 'start capture' we do not know (yet) all the ports
	 * we're currently using.
	 */
	if (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP)
	{
		struct bpf_program fcode;

		if (pcap_createfilter_norpcappkt(fp, &fcode) == -1)
			goto error;

		/* We cannot use 'pcap_setfilter_rpcap' because formally the capture has not been started yet */
		/* (the 'pr->rmt_capstarted' variable will be updated some lines below) */
		if (pcap_updatefilter_remote(fp, &fcode) == -1)
			goto error;

		pcap_freecode(&fcode);
	}

	pr->rmt_capstarted = 1;
	return 0;

error:
	/*
	 * When the connection has been established, we have to close it. So, at the
	 * beginning of this function, if an error occur we return immediately with
	 * a return NULL; when the connection is established, we have to come here
	 * ('goto error;') in order to close everything properly.
	 */

	/*
	 * Discard the rest of the message.
	 * We already reported an error; if this gets an error, just
	 * drive on.
	 */
	(void)rpcap_discard(pr->rmt_sockctrl, plen, NULL);

error_nodiscard:
	if ((sockdata) && (sockdata != -1))		/* we can be here because sockdata said 'error' */
		sock_close(sockdata, NULL, 0);

	if (!active)
		sock_close(pr->rmt_sockctrl, NULL, 0);

	if (addrinfo != NULL)
		freeaddrinfo(addrinfo);

	/*
	 * We do not have to call pcap_close() here, because this function is always called
	 * by the user in case something bad happens
	 */
#if 0
	if (fp)
	{
		pcap_close(fp);
		fp= NULL;
	}
#endif

	return -1;
}

/*
 * This function takes a bpf program and sends it to the other host.
 *
 * This function can be called in two cases:
 * - pcap_startcapture_remote() is called (we have to send the filter
 *   along with the 'start capture' command)
 * - we want to udpate the filter during a capture (i.e. pcap_setfilter()
 *   after the capture has been started)
 *
 * This function serializes the filter into the sending buffer ('sendbuf',
 * passed as a parameter) and return back. It does not send anything on
 * the network.
 *
 * \param fp: the pcap_t descriptor of the device currently opened.
 *
 * \param sendbuf: the buffer on which the serialized data has to copied.
 *
 * \param sendbufidx: it is used to return the abounf of bytes copied into the buffer.
 *
 * \param prog: the bpf program we have to copy.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message (if one)
 * is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_pack_bpffilter(pcap_t *fp, char *sendbuf, int *sendbufidx, struct bpf_program *prog)
{
	struct rpcap_filter *filter;
	struct rpcap_filterbpf_insn *insn;
	struct bpf_insn *bf_insn;
	struct bpf_program fake_prog;		/* To be used just in case the user forgot to set a filter */
	unsigned int i;

	if (prog->bf_len == 0)	/* No filters have been specified; so, let's apply a "fake" filter */
	{
		if (pcap_compile(fp, &fake_prog, NULL /* buffer */, 1, 0) == -1)
			return -1;

		prog = &fake_prog;
	}

	filter = (struct rpcap_filter *) sendbuf;

	if (sock_bufferize(NULL, sizeof(struct rpcap_filter), NULL, sendbufidx,
		RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	filter->filtertype = htons(RPCAP_UPDATEFILTER_BPF);
	filter->nitems = htonl((int32)prog->bf_len);

	if (sock_bufferize(NULL, prog->bf_len * sizeof(struct rpcap_filterbpf_insn),
		NULL, sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	insn = (struct rpcap_filterbpf_insn *) (filter + 1);
	bf_insn = prog->bf_insns;

	for (i = 0; i < prog->bf_len; i++)
	{
		insn->code = htons(bf_insn->code);
		insn->jf = bf_insn->jf;
		insn->jt = bf_insn->jt;
		insn->k = htonl(bf_insn->k);

		insn++;
		bf_insn++;
	}

	return 0;
}

/*
 * This function updates a filter on a remote host.
 *
 * It is called when the user wants to update a filter.
 * In case we're capturing from the network, it sends the filter to our
 * peer.
 * This function is *not* called automatically when the user calls
 * pcap_setfilter().
 * There will be two cases:
 * - the capture has been started: in this case, pcap_setfilter_rpcap()
 *   calls pcap_updatefilter_remote()
 * - the capture has not started yet: in this case, pcap_setfilter_rpcap()
 *   stores the filter into the pcap_t structure, and then the filter is
 *   sent with pcap_startcap().
 *
 * WARNING This function *does not* clear the packet currently into the
 * buffers. Therefore, the user has to expect to receive some packets
 * that are related to the previous filter.  If you want to discard all
 * the packets before applying a new filter, you have to close the
 * current capture session and start a new one.
 *
 * XXX - we really should have pcap_setfilter() always discard packets
 * received with the old filter, and have a separate pcap_setfilter_noflush()
 * function that doesn't discard any packets.
 */
static int pcap_updatefilter_remote(pcap_t *fp, struct bpf_program *prog)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */
	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data to be sent is buffered */
	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
	struct rpcap_header header;		/* To keep the reply message */

	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
		RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	rpcap_createhdr((struct rpcap_header *) sendbuf,
	    pr->protocol_version, RPCAP_MSG_UPDATEFILTER_REQ, 0,
	    sizeof(struct rpcap_filter) + prog->bf_len * sizeof(struct rpcap_filterbpf_insn));

	if (pcap_pack_bpffilter(fp, &sendbuf[sendbufidx], &sendbufidx, prog))
		return -1;

	if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
	    PCAP_ERRBUF_SIZE) < 0)
		return -1;

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
	    RPCAP_MSG_UPDATEFILTER_REQ, &header, fp->errbuf) == -1)
		return -1;

	/*
	 * It shouldn't have any contents; discard it if it does.
	 */
	if (rpcap_discard(pr->rmt_sockctrl, header.plen, fp->errbuf) == -1)
		return -1;

	return 0;
}

static void
pcap_save_current_filter_rpcap(pcap_t *fp, const char *filter)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */

	/*
	 * Check if:
	 *  - We are on an remote capture
	 *  - we do not want to capture RPCAP traffic
	 *
	 * If so, we have to save the current filter, because we have to
	 * add some piece of stuff later
	 */
	if (pr->rmt_clientside &&
	    (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP))
	{
		if (pr->currentfilter)
			free(pr->currentfilter);

		if (filter == NULL)
			filter = "";

		pr->currentfilter = strdup(filter);
	}
}

/*
 * This function sends a filter to a remote host.
 *
 * This function is called when the user wants to set a filter.
 * It sends the filter to our peer.
 * This function is called automatically when the user calls pcap_setfilter().
 *
 * Parameters and return values are exactly the same of pcap_setfilter().
 */
static int pcap_setfilter_rpcap(pcap_t *fp, struct bpf_program *prog)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */

	if (!pr->rmt_capstarted)
	{
		/* copy filter into the pcap_t structure */
		if (install_bpf_program(fp, prog) == -1)
			return -1;
		return 0;
	}

	/* we have to update a filter during run-time */
	if (pcap_updatefilter_remote(fp, prog))
		return -1;

	return 0;
}

/*
 * This function updates the current filter in order not to capture rpcap
 * packets.
 *
 * This function is called *only* when the user wants exclude RPCAP packets
 * related to the current session from the captured packets.
 *
 * \return '0' if everything is fine, '-1' otherwise. The error message (if one)
 * is returned into the 'errbuf' field of the pcap_t structure.
 */
static int pcap_createfilter_norpcappkt(pcap_t *fp, struct bpf_program *prog)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */
	int RetVal = 0;

	/* We do not want to capture our RPCAP traffic. So, let's update the filter */
	if (pr->rmt_flags & PCAP_OPENFLAG_NOCAPTURE_RPCAP)
	{
		struct sockaddr_storage saddr;		/* temp, needed to retrieve the network data port chosen on the local machine */
		socklen_t saddrlen;					/* temp, needed to retrieve the network data port chosen on the local machine */
		char myaddress[128];
		char myctrlport[128];
		char mydataport[128];
		char peeraddress[128];
		char peerctrlport[128];
		char *newfilter;

		/* Get the name/port of our peer */
		saddrlen = sizeof(struct sockaddr_storage);
		if (getpeername(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
		{
			sock_geterror("getpeername()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		if (getnameinfo((struct sockaddr *) &saddr, saddrlen, peeraddress,
			sizeof(peeraddress), peerctrlport, sizeof(peerctrlport), NI_NUMERICHOST | NI_NUMERICSERV))
		{
			sock_geterror("getnameinfo()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		/* We cannot check the data port, because this is available only in case of TCP sockets */
		/* Get the name/port of the current host */
		if (getsockname(pr->rmt_sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
		{
			sock_geterror("getsockname()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		/* Get the local port the system picked up */
		if (getnameinfo((struct sockaddr *) &saddr, saddrlen, myaddress,
			sizeof(myaddress), myctrlport, sizeof(myctrlport), NI_NUMERICHOST | NI_NUMERICSERV))
		{
			sock_geterror("getnameinfo()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		/* Let's now check the data port */
		if (getsockname(pr->rmt_sockdata, (struct sockaddr *) &saddr, &saddrlen) == -1)
		{
			sock_geterror("getsockname()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		/* Get the local port the system picked up */
		if (getnameinfo((struct sockaddr *) &saddr, saddrlen, NULL, 0, mydataport, sizeof(mydataport), NI_NUMERICSERV))
		{
			sock_geterror("getnameinfo()", fp->errbuf, PCAP_ERRBUF_SIZE);
			return -1;
		}

		if (pr->currentfilter && pr->currentfilter[0] != '\0')
		{
			/*
			 * We have a current filter; add items to it to
			 * filter out this rpcap session.
			 */
			if (pcap_asprintf(&newfilter,
			    "(%s) and not (host %s and host %s and port %s and port %s) and not (host %s and host %s and port %s)",
			    pr->currentfilter, myaddress, peeraddress,
			    myctrlport, peerctrlport, myaddress, peeraddress,
			    mydataport) == -1)
			{
				/* Failed. */
				pcap_snprintf(fp->errbuf, PCAP_ERRBUF_SIZE,
				    "Can't allocate memory for new filter");
				return -1;
			}
		}
		else
		{
			/*
			 * We have no current filter; construct a filter to
			 * filter out this rpcap session.
			 */
			if (pcap_asprintf(&newfilter,
			    "not (host %s and host %s and port %s and port %s) and not (host %s and host %s and port %s)",
			    myaddress, peeraddress, myctrlport, peerctrlport,
			    myaddress, peeraddress, mydataport) == -1)
			{
				/* Failed. */
				pcap_snprintf(fp->errbuf, PCAP_ERRBUF_SIZE,
				    "Can't allocate memory for new filter");
				return -1;
			}
		}

		/*
		 * This is only an hack to prevent the save_current_filter
		 * routine, which will be called when we call pcap_compile(),
		 * from saving the modified filter.
		 */
		pr->rmt_clientside = 0;

		if (pcap_compile(fp, prog, newfilter, 1, 0) == -1)
			RetVal = -1;

		/* Undo the hack. */
		pr->rmt_clientside = 1;

		free(newfilter);
	}

	return RetVal;
}

/*
 * This function sets sampling parameters in the remote host.
 *
 * It is called when the user wants to set activate sampling on the
 * remote host.
 *
 * Sampling parameters are defined into the 'pcap_t' structure.
 *
 * \param p: the pcap_t descriptor of the device currently opened.
 *
 * \return '0' if everything is OK, '-1' is something goes wrong. The
 * error message is returned in the 'errbuf' member of the pcap_t structure.
 */
static int pcap_setsampling_remote(pcap_t *fp)
{
	struct pcap_rpcap *pr = fp->priv;	/* structure used when doing a remote live capture */
	char sendbuf[RPCAP_NETBUF_SIZE];/* temporary buffer in which data to be sent is buffered */
	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
	struct rpcap_header header;		/* To keep the reply message */
	struct rpcap_sampling *sampling_pars;	/* Structure that is needed to send sampling parameters to the remote host */

	/* If no samping is requested, return 'ok' */
	if (fp->rmt_samp.method == PCAP_SAMP_NOSAMP)
		return 0;

	/*
	 * Check for sampling parameters that don't fit in a message.
	 * We'll let the server complain about invalid parameters
	 * that do fit into the message.
	 */
	if (fp->rmt_samp.method < 0 || fp->rmt_samp.method > 255) {
		pcap_snprintf(fp->errbuf, PCAP_ERRBUF_SIZE,
		    "Invalid sampling method %d", fp->rmt_samp.method);
		return -1;
	}
	if (fp->rmt_samp.value < 0 || fp->rmt_samp.value > 65535) {
		pcap_snprintf(fp->errbuf, PCAP_ERRBUF_SIZE,
		    "Invalid sampling value %d", fp->rmt_samp.value);
		return -1;
	}

	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	rpcap_createhdr((struct rpcap_header *) sendbuf,
	    pr->protocol_version, RPCAP_MSG_SETSAMPLING_REQ, 0,
	    sizeof(struct rpcap_sampling));

	/* Fill the structure needed to open an adapter remotely */
	sampling_pars = (struct rpcap_sampling *) &sendbuf[sendbufidx];

	if (sock_bufferize(NULL, sizeof(struct rpcap_sampling), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, fp->errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	memset(sampling_pars, 0, sizeof(struct rpcap_sampling));

	sampling_pars->method = (uint8)fp->rmt_samp.method;
	sampling_pars->value = (uint16)htonl(fp->rmt_samp.value);

	if (sock_send(pr->rmt_sockctrl, sendbuf, sendbufidx, fp->errbuf,
	    PCAP_ERRBUF_SIZE) < 0)
		return -1;

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(pr->rmt_sockctrl, pr->protocol_version,
	    RPCAP_MSG_SETSAMPLING_REQ, &header, fp->errbuf) == -1)
		return -1;

	/*
	 * It shouldn't have any contents; discard it if it does.
	 */
	if (rpcap_discard(pr->rmt_sockctrl, header.plen, fp->errbuf) == -1)
		return -1;

	return 0;
}

/*********************************************************
 *                                                       *
 * Miscellaneous functions                               *
 *                                                       *
 *********************************************************/

/*
 * This function performs authentication and protocol version
 * negotiation.  It is required in order to open the connection
 * with the other end party.
 *
 * It sends authentication parameters on the control socket and
 * reads the reply.  If the reply is a success indication, it
 * checks whether the reply includes minimum and maximum supported
 * versions from the server; if not, it assumes both are 0, as
 * that means it's an older server that doesn't return supported
 * version numbers in authentication replies, so it only supports
 * version 0.  It then tries to determine the maximum version
 * supported both by us and by the server.  If it can find such a
 * version, it sets us up to use that version; otherwise, it fails,
 * indicating that there is no version supported by us and by the
 * server.
 *
 * \param sock: the socket we are currently using.
 *
 * \param ver: pointer to variable to which to set the protocol version
 * number we selected.
 *
 * \param auth: authentication parameters that have to be sent.
 *
 * \param errbuf: a pointer to a user-allocated buffer (of size
 * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
 * is one). It could be a network problem or the fact that the authorization
 * failed.
 *
 * \return '0' if everything is fine, '-1' for an error.  For errors,
 * an error message string is returned in the 'errbuf' variable.
 */
static int rpcap_doauth(SOCKET sockctrl, uint8 *ver, struct pcap_rmtauth *auth, char *errbuf)
{
	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data that has to be sent is buffered */
	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
	uint16 length;				/* length of the payload of this message */
	struct rpcap_auth *rpauth;
	uint16 auth_type;
	struct rpcap_header header;
	size_t str_length;
	uint32 plen;
	struct rpcap_authreply authreply;	/* authentication reply message */
	uint8 ourvers;

	if (auth)
	{
		switch (auth->type)
		{
		case RPCAP_RMTAUTH_NULL:
			length = sizeof(struct rpcap_auth);
			break;

		case RPCAP_RMTAUTH_PWD:
			length = sizeof(struct rpcap_auth);
			if (auth->username)
			{
				str_length = strlen(auth->username);
				if (str_length > 65535)
				{
					pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "User name is too long (> 65535 bytes)");
					return -1;
				}
				length += (uint16)str_length;
			}
			if (auth->password)
			{
				str_length = strlen(auth->password);
				if (str_length > 65535)
				{
					pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Password is too long (> 65535 bytes)");
					return -1;
				}
				length += (uint16)str_length;
			}
			break;

		default:
			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Authentication type not recognized.");
			return -1;
		}

		auth_type = (uint16)auth->type;
	}
	else
	{
		auth_type = RPCAP_RMTAUTH_NULL;
		length = sizeof(struct rpcap_auth);
	}

	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	rpcap_createhdr((struct rpcap_header *) sendbuf, 0,
	    RPCAP_MSG_AUTH_REQ, 0, length);

	rpauth = (struct rpcap_auth *) &sendbuf[sendbufidx];

	if (sock_bufferize(NULL, sizeof(struct rpcap_auth), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
		return -1;

	memset(rpauth, 0, sizeof(struct rpcap_auth));

	rpauth->type = htons(auth_type);

	if (auth_type == RPCAP_RMTAUTH_PWD)
	{
		if (auth->username)
			rpauth->slen1 = (uint16)strlen(auth->username);
		else
			rpauth->slen1 = 0;

		if (sock_bufferize(auth->username, rpauth->slen1, sendbuf,
			&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
			return -1;

		if (auth->password)
			rpauth->slen2 = (uint16)strlen(auth->password);
		else
			rpauth->slen2 = 0;

		if (sock_bufferize(auth->password, rpauth->slen2, sendbuf,
			&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
			return -1;

		rpauth->slen1 = htons(rpauth->slen1);
		rpauth->slen2 = htons(rpauth->slen2);
	}

	if (sock_send(sockctrl, sendbuf, sendbufidx, errbuf,
	    PCAP_ERRBUF_SIZE) < 0)
		return -1;

	/* Receive and process the reply message header */
	if (rpcap_process_msg_header(sockctrl, 0, RPCAP_MSG_AUTH_REQ,
	    &header, errbuf) == -1)
		return -1;

	/*
	 * OK, it's an authentication reply, so we're logged in.
	 *
	 * Did it send any additional information?
	 */
	plen = header.plen;
	if (plen != 0)
	{
		/* Yes - is it big enough to be version information? */
		if (plen < sizeof(struct rpcap_authreply))
		{
			/* No - discard it and fail. */
			(void)rpcap_discard(sockctrl, plen, NULL);
			return -1;
		}

		/* Read the reply body */
		if (rpcap_recv(sockctrl, (char *)&authreply,
		    sizeof(struct rpcap_authreply), &plen, errbuf) == -1)
		{
			(void)rpcap_discard(sockctrl, plen, NULL);
			return -1;
		}

		/* Discard the rest of the message, if there is any. */
		if (rpcap_discard(sockctrl, plen, errbuf) == -1)
			return -1;

		/*
		 * Check the minimum and maximum versions for sanity;
		 * the minimum must be <= the maximum.
		 */
		if (authreply.minvers > authreply.maxvers)
		{
			/*
			 * Bogus - give up on this server.
			 */
			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "The server's minimum supported protocol version is greater than its maximum supported protocol version");
			return -1;
		}
	}
	else
	{
		/* No - it supports only version 0. */
		authreply.minvers = 0;
		authreply.maxvers = 0;
	}

	/*
	 * OK, let's start with the maximum version the server supports.
	 */
	ourvers = authreply.maxvers;

#if RPCAP_MIN_VERSION != 0
	/*
	 * If that's less than the minimum version we support, we
	 * can't communicate.
	 */
	if (ourvers < RPCAP_MIN_VERSION)
		goto novers;
#endif

	/*
	 * If that's greater than the maximum version we support,
	 * choose the maximum version we support.
	 */
	if (ourvers > RPCAP_MAX_VERSION)
	{
		ourvers = RPCAP_MAX_VERSION;

		/*
		 * If that's less than the minimum version they
		 * support, we can't communicate.
		 */
		if (ourvers < authreply.minvers)
			goto novers;
	}

	*ver = ourvers;
	return 0;

novers:
	/*
	 * There is no version we both support; that is a fatal error.
	 */
	pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
	    "The server doesn't support any protocol version that we support");
	return -1;
}

/* We don't currently support non-blocking mode. */
static int
pcap_getnonblock_rpcap(pcap_t *p)
{
	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
	    "Non-blocking mode isn't supported for capturing remotely with rpcap");
	return (-1);
}

static int
pcap_setnonblock_rpcap(pcap_t *p, int nonblock _U_)
{
	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
	    "Non-blocking mode isn't supported for capturing remotely with rpcap");
	return (-1);
}

static int
rpcap_setup_session(const char *source, struct pcap_rmtauth *auth,
    int *activep, SOCKET *sockctrlp, uint8 *protocol_versionp,
    char *host, char *port, char *iface, char *errbuf)
{
	int type;
	struct activehosts *activeconn;		/* active connection, if there is one */
	int error;				/* 1 if rpcap_remoteact_getsock got an error */

	/*
	 * Determine the type of the source (NULL, file, local, remote).
	 * You must have a valid source string even if we're in active mode,
	 * because otherwise the call to the following function will fail.
	 */
	if (pcap_parsesrcstr(source, &type, host, port, iface, errbuf) == -1)
		return -1;

	/*
	 * It must be remote.
	 */
	if (type != PCAP_SRC_IFREMOTE)
	{
		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
		    "Non-remote interface passed to remote capture routine");
		return -1;
	}

	/* Warning: this call can be the first one called by the user. */
	/* For this reason, we have to initialize the WinSock support. */
	if (sock_init(errbuf, PCAP_ERRBUF_SIZE) == -1)
		return -1;

	/* Check for active mode */
	activeconn = rpcap_remoteact_getsock(host, &error, errbuf);
	if (activeconn != NULL)
	{
		*activep = 1;
		*sockctrlp = activeconn->sockctrl;
		*protocol_versionp = activeconn->protocol_version;
	}
	else
	{
		*activep = 0;
		struct addrinfo hints;		/* temp variable needed to resolve hostnames into to socket representation */
		struct addrinfo *addrinfo;	/* temp variable needed to resolve hostnames into to socket representation */

		if (error)
		{
			/*
			 * Call failed.
			 */
			return -1;
		}

		/*
		 * We're not in active mode; let's try to open a new
		 * control connection.
		 */
		memset(&hints, 0, sizeof(struct addrinfo));
		hints.ai_family = PF_UNSPEC;
		hints.ai_socktype = SOCK_STREAM;

		if (port[0] == 0)
		{
			/* the user chose not to specify the port */
			if (sock_initaddress(host, RPCAP_DEFAULT_NETPORT,
			    &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
				return -1;
		}
		else
		{
			if (sock_initaddress(host, port, &hints, &addrinfo,
			    errbuf, PCAP_ERRBUF_SIZE) == -1)
				return -1;
		}

		if ((*sockctrlp = sock_open(addrinfo, SOCKOPEN_CLIENT, 0,
		    errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
		{
			freeaddrinfo(addrinfo);
			return -1;
		}

		/* addrinfo is no longer used */
		freeaddrinfo(addrinfo);
		addrinfo = NULL;

		if (rpcap_doauth(*sockctrlp, protocol_versionp, auth,
		    errbuf) == -1)
		{
			sock_close(*sockctrlp, NULL, 0);
			return -1;
		}
	}
	return 0;
}

/*
 * This function opens a remote adapter by opening an RPCAP connection and
 * so on.
 *
 * It does the job of pcap_open_live() for a remote interface; it's called
 * by pcap_open() for remote interfaces.
 *
 * We do not start the capture until pcap_startcapture_remote() is called.
 *
 * This is because, when doing a remote capture, we cannot start capturing
 * data as soon as the 'open adapter' command is sent. Suppose the remote
 * adapter is already overloaded; if we start a capture (which, by default,
 * has a NULL filter) the new traffic can saturate the network.
 *
 * Instead, we want to "open" the adapter, then send a "start capture"
 * command only when we're ready to start the capture.
 * This function does this job: it sends an "open adapter" command
 * (according to the RPCAP protocol), but it does not start the capture.
 *
 * Since the other libpcap functions do not share this way of life, we
 * have to do some dirty things in order to make everything work.
 *
 * \param source: see pcap_open().
 * \param snaplen: see pcap_open().
 * \param flags: see pcap_open().
 * \param read_timeout: see pcap_open().
 * \param auth: see pcap_open().
 * \param errbuf: see pcap_open().
 *
 * \return a pcap_t pointer in case of success, NULL otherwise. In case of
 * success, the pcap_t pointer can be used as a parameter to the following
 * calls (pcap_compile() and so on). In case of problems, errbuf contains
 * a text explanation of error.
 *
 * WARNING: In case we call pcap_compile() and the capture has not yet
 * been started, the filter will be saved into the pcap_t structure,
 * and it will be sent to the other host later (when
 * pcap_startcapture_remote() is called).
 */
pcap_t *pcap_open_rpcap(const char *source, int snaplen, int flags, int read_timeout, struct pcap_rmtauth *auth, char *errbuf)
{
	pcap_t *fp;
	char *source_str;
	struct pcap_rpcap *pr;		/* structure used when doing a remote live capture */
	char host[PCAP_BUF_SIZE], ctrlport[PCAP_BUF_SIZE], iface[PCAP_BUF_SIZE];
	SOCKET sockctrl;
	uint8 protocol_version;			/* negotiated protocol version */
	int active;
	uint32 plen;
	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data to be sent is buffered */
	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */

	/* RPCAP-related variables */
	struct rpcap_header header;		/* header of the RPCAP packet */
	struct rpcap_openreply openreply;	/* open reply message */

	fp = pcap_create_common(errbuf, sizeof (struct pcap_rpcap));
	if (fp == NULL)
	{
		return NULL;
	}
	source_str = strdup(source);
	if (source_str == NULL) {
		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
		    errno, "malloc");
		return NULL;
	}

	/*
	 * 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.
	 *
	 * XXX - should we leave this up to the remote server to
	 * do?
	 */
	if (snaplen <= 0 || snaplen > MAXIMUM_SNAPLEN)
		snaplen = MAXIMUM_SNAPLEN;

	fp->opt.device = source_str;
	fp->snapshot = snaplen;
	fp->opt.timeout = read_timeout;
	pr = fp->priv;
	pr->rmt_flags = flags;

	/*
	 * Attempt to set up the session with the server.
	 */
	if (rpcap_setup_session(fp->opt.device, auth, &active, &sockctrl,
	    &protocol_version, host, ctrlport, iface, errbuf) == -1)
	{
		/* Session setup failed. */
		pcap_close(fp);
		return NULL;
	}

	/*
	 * Now it's time to start playing with the RPCAP protocol
	 * RPCAP open command: create the request message
	 */
	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL,
		&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
		goto error_nodiscard;

	rpcap_createhdr((struct rpcap_header *) sendbuf, protocol_version,
	    RPCAP_MSG_OPEN_REQ, 0, (uint32) strlen(iface));

	if (sock_bufferize(iface, (int) strlen(iface), sendbuf, &sendbufidx,
		RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
		goto error_nodiscard;

	if (sock_send(sockctrl, sendbuf, sendbufidx, errbuf,
	    PCAP_ERRBUF_SIZE) < 0)
		goto error_nodiscard;

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(sockctrl, protocol_version,
	    RPCAP_MSG_OPEN_REQ, &header, errbuf) == -1)
		goto error_nodiscard;
	plen = header.plen;

	/* Read the reply body */
	if (rpcap_recv(sockctrl, (char *)&openreply,
	    sizeof(struct rpcap_openreply), &plen, errbuf) == -1)
		goto error;

	/* Discard the rest of the message, if there is any. */
	if (rpcap_discard(sockctrl, plen, errbuf) == -1)
		goto error_nodiscard;

	/* Set proper fields into the pcap_t struct */
	fp->linktype = ntohl(openreply.linktype);
	fp->tzoff = ntohl(openreply.tzoff);
	pr->rmt_sockctrl = sockctrl;
	pr->protocol_version = protocol_version;
	pr->rmt_clientside = 1;

	/* This code is duplicated from the end of this function */
	fp->read_op = pcap_read_rpcap;
	fp->save_current_filter_op = pcap_save_current_filter_rpcap;
	fp->setfilter_op = pcap_setfilter_rpcap;
	fp->getnonblock_op = pcap_getnonblock_rpcap;
	fp->setnonblock_op = pcap_setnonblock_rpcap;
	fp->stats_op = pcap_stats_rpcap;
#ifdef _WIN32
	fp->stats_ex_op = pcap_stats_ex_rpcap;
#endif
	fp->cleanup_op = pcap_cleanup_rpcap;

	fp->activated = 1;
	return fp;

error:
	/*
	 * When the connection has been established, we have to close it. So, at the
	 * beginning of this function, if an error occur we return immediately with
	 * a return NULL; when the connection is established, we have to come here
	 * ('goto error;') in order to close everything properly.
	 */

	/*
	 * Discard the rest of the message.
	 * We already reported an error; if this gets an error, just
	 * drive on.
	 */
	(void)rpcap_discard(sockctrl, plen, NULL);

error_nodiscard:
	if (!active)
		sock_close(sockctrl, NULL, 0);

	pcap_close(fp);
	return NULL;
}

/* String identifier to be used in the pcap_findalldevs_ex() */
#define PCAP_TEXT_SOURCE_ADAPTER "Network adapter"
#define PCAP_TEXT_SOURCE_ADAPTER_LEN (sizeof PCAP_TEXT_SOURCE_ADAPTER - 1)
/* String identifier to be used in the pcap_findalldevs_ex() */
#define PCAP_TEXT_SOURCE_ON_REMOTE_HOST "on remote node"
#define PCAP_TEXT_SOURCE_ON_REMOTE_HOST_LEN (sizeof PCAP_TEXT_SOURCE_ON_REMOTE_HOST - 1)

static void
freeaddr(struct pcap_addr *addr)
{
	free(addr->addr);
	free(addr->netmask);
	free(addr->broadaddr);
	free(addr->dstaddr);
	free(addr);
}

int
pcap_findalldevs_ex_remote(const char *source, struct pcap_rmtauth *auth, pcap_if_t **alldevs, char *errbuf)
{
	uint8 protocol_version;		/* protocol version */
	SOCKET sockctrl;		/* socket descriptor of the control connection */
	uint32 plen;
	struct rpcap_header header;	/* structure that keeps the general header of the rpcap protocol */
	int i, j;		/* temp variables */
	int nif;		/* Number of interfaces listed */
	int active;			/* 'true' if we the other end-party is in active mode */
	char host[PCAP_BUF_SIZE], port[PCAP_BUF_SIZE];
	char tmpstring[PCAP_BUF_SIZE + 1];		/* Needed to convert names and descriptions from 'old' syntax to the 'new' one */
	pcap_if_t *lastdev;	/* Last device in the pcap_if_t list */
	pcap_if_t *dev;		/* Device we're adding to the pcap_if_t list */

	/* List starts out empty. */
	(*alldevs) = NULL;
	lastdev = NULL;

	/*
	 * Attempt to set up the session with the server.
	 */
	if (rpcap_setup_session(source, auth, &active, &sockctrl,
	    &protocol_version, host, port, NULL, errbuf) == -1)
	{
		/* Session setup failed. */
		return -1;
	}

	/* RPCAP findalldevs command */
	rpcap_createhdr(&header, protocol_version, RPCAP_MSG_FINDALLIF_REQ,
	    0, 0);

	if (sock_send(sockctrl, (char *)&header, sizeof(struct rpcap_header),
	    errbuf, PCAP_ERRBUF_SIZE) < 0)
		goto error_nodiscard;

	/* Receive and process the reply message header. */
	if (rpcap_process_msg_header(sockctrl, protocol_version,
	    RPCAP_MSG_FINDALLIF_REQ, &header, errbuf) == -1)
		goto error_nodiscard;

	plen = header.plen;

	/* read the number of interfaces */
	nif = ntohs(header.value);

	/* loop until all interfaces have been received */
	for (i = 0; i < nif; i++)
	{
		struct rpcap_findalldevs_if findalldevs_if;
		char tmpstring2[PCAP_BUF_SIZE + 1];		/* Needed to convert names and descriptions from 'old' syntax to the 'new' one */
		struct pcap_addr *addr, *prevaddr;

		tmpstring2[PCAP_BUF_SIZE] = 0;

		/* receive the findalldevs structure from remote host */
		if (rpcap_recv(sockctrl, (char *)&findalldevs_if,
		    sizeof(struct rpcap_findalldevs_if), &plen, errbuf) == -1)
			goto error;

		findalldevs_if.namelen = ntohs(findalldevs_if.namelen);
		findalldevs_if.desclen = ntohs(findalldevs_if.desclen);
		findalldevs_if.naddr = ntohs(findalldevs_if.naddr);

		/* allocate the main structure */
		dev = (pcap_if_t *)malloc(sizeof(pcap_if_t));
		if (dev == NULL)
		{
			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
			    errno, "malloc() failed");
			goto error;
		}

		/* Initialize the structure to 'zero' */
		memset(dev, 0, sizeof(pcap_if_t));

		/* Append it to the list. */
		if (lastdev == NULL)
		{
			/*
			 * List is empty, so it's also the first device.
			 */
			*alldevs = dev;
		}
		else
		{
			/*
			 * Append after the last device.
			 */
			lastdev->next = dev;
		}
		/* It's now the last device. */
		lastdev = dev;

		/* allocate mem for name and description */
		if (findalldevs_if.namelen)
		{

			if (findalldevs_if.namelen >= sizeof(tmpstring))
			{
				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Interface name too long");
				goto error;
			}

			/* Retrieve adapter name */
			if (rpcap_recv(sockctrl, tmpstring,
			    findalldevs_if.namelen, &plen, errbuf) == -1)
				goto error;

			tmpstring[findalldevs_if.namelen] = 0;

			/* Create the new device identifier */
			if (pcap_createsrcstr(tmpstring2, PCAP_SRC_IFREMOTE,
			    host, port, tmpstring, errbuf) == -1)
				goto error;

			dev->name = strdup(tmpstring2);
			if (dev->name == NULL)
			{
				pcap_fmt_errmsg_for_errno(errbuf,
				    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
				goto error;
			}
		}

		if (findalldevs_if.desclen)
		{
			if (findalldevs_if.desclen >= sizeof(tmpstring))
			{
				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Interface description too long");
				goto error;
			}

			/* Retrieve adapter description */
			if (rpcap_recv(sockctrl, tmpstring,
			    findalldevs_if.desclen, &plen, errbuf) == -1)
				goto error;

			tmpstring[findalldevs_if.desclen] = 0;

			if (pcap_asprintf(&dev->description,
			    "%s '%s' %s %s", PCAP_TEXT_SOURCE_ADAPTER,
			    tmpstring, PCAP_TEXT_SOURCE_ON_REMOTE_HOST, host) == -1)
			{
				pcap_fmt_errmsg_for_errno(errbuf,
				    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
				goto error;
			}
		}

		dev->flags = ntohl(findalldevs_if.flags);

		prevaddr = NULL;
		/* loop until all addresses have been received */
		for (j = 0; j < findalldevs_if.naddr; j++)
		{
			struct rpcap_findalldevs_ifaddr ifaddr;

			/* Retrieve the interface addresses */
			if (rpcap_recv(sockctrl, (char *)&ifaddr,
			    sizeof(struct rpcap_findalldevs_ifaddr),
			    &plen, errbuf) == -1)
				goto error;

			/*
			 * Deserialize all the address components.
			 */
			addr = (struct pcap_addr *) malloc(sizeof(struct pcap_addr));
			if (addr == NULL)
			{
				pcap_fmt_errmsg_for_errno(errbuf,
				    PCAP_ERRBUF_SIZE, errno, "malloc() failed");
				goto error;
			}
			addr->next = NULL;
			addr->addr = NULL;
			addr->netmask = NULL;
			addr->broadaddr = NULL;
			addr->dstaddr = NULL;

			if (rpcap_deseraddr(&ifaddr.addr,
				(struct sockaddr_storage **) &addr->addr, errbuf) == -1)
			{
				freeaddr(addr);
				goto error;
			}
			if (rpcap_deseraddr(&ifaddr.netmask,
				(struct sockaddr_storage **) &addr->netmask, errbuf) == -1)
			{
				freeaddr(addr);
				goto error;
			}
			if (rpcap_deseraddr(&ifaddr.broadaddr,
				(struct sockaddr_storage **) &addr->broadaddr, errbuf) == -1)
			{
				freeaddr(addr);
				goto error;
			}
			if (rpcap_deseraddr(&ifaddr.dstaddr,
				(struct sockaddr_storage **) &addr->dstaddr, errbuf) == -1)
			{
				freeaddr(addr);
				goto error;
			}

			if ((addr->addr == NULL) && (addr->netmask == NULL) &&
				(addr->broadaddr == NULL) && (addr->dstaddr == NULL))
			{
				/*
				 * None of the addresses are IPv4 or IPv6
				 * addresses, so throw this entry away.
				 */
				free(addr);
			}
			else
			{
				/*
				 * Add this entry to the list.
				 */
				if (prevaddr == NULL)
				{
					dev->addresses = addr;
				}
				else
				{
					prevaddr->next = addr;
				}
				prevaddr = addr;
			}
		}
	}

	/* Discard the rest of the message. */
	if (rpcap_discard(sockctrl, plen, errbuf) == 1)
		goto error_nodiscard;

	/* Control connection has to be closed only in case the remote machine is in passive mode */
	if (!active)
	{
		/* DO not send RPCAP_CLOSE, since we did not open a pcap_t; no need to free resources */
		if (sock_close(sockctrl, errbuf, PCAP_ERRBUF_SIZE))
			return -1;
	}

	/* To avoid inconsistencies in the number of sock_init() */
	sock_cleanup();

	return 0;

error:
	/*
	 * In case there has been an error, I don't want to overwrite it with a new one
	 * if the following call fails. I want to return always the original error.
	 *
	 * Take care: this connection can already be closed when we try to close it.
	 * This happens because a previous error in the rpcapd, which requested to
	 * closed the connection. In that case, we already recognized that into the
	 * rpspck_isheaderok() and we already acknowledged the closing.
	 * In that sense, this call is useless here (however it is needed in case
	 * the client generates the error).
	 *
	 * Checks if all the data has been read; if not, discard the data in excess
	 */
	(void) rpcap_discard(sockctrl, plen, NULL);

error_nodiscard:
	/* Control connection has to be closed only in case the remote machine is in passive mode */
	if (!active)
		sock_close(sockctrl, NULL, 0);

	/* To avoid inconsistencies in the number of sock_init() */
	sock_cleanup();

	/* Free whatever interfaces we've allocated. */
	pcap_freealldevs(*alldevs);

	return -1;
}

/*
 * Active mode routines.
 *
 * The old libpcap API is somewhat ugly, and makes active mode difficult
 * to implement; we provide some APIs for it that work only with rpcap.
 */

SOCKET pcap_remoteact_accept(const char *address, const char *port, const char *hostlist, char *connectinghost, struct pcap_rmtauth *auth, char *errbuf)
{
	/* socket-related variables */
	struct addrinfo hints;			/* temporary struct to keep settings needed to open the new socket */
	struct addrinfo *addrinfo;		/* keeps the addrinfo chain; required to open a new socket */
	struct sockaddr_storage from;	/* generic sockaddr_storage variable */
	socklen_t fromlen;				/* keeps the length of the sockaddr_storage variable */
	SOCKET sockctrl;				/* keeps the main socket identifier */
	uint8 protocol_version;			/* negotiated protocol version */
	struct activehosts *temp, *prev;	/* temp var needed to scan he host list chain */

	*connectinghost = 0;		/* just in case */

	/* Prepare to open a new server socket */
	memset(&hints, 0, sizeof(struct addrinfo));
	/* WARNING Currently it supports only ONE socket family among ipv4 and IPv6  */
	hints.ai_family = AF_INET;		/* PF_UNSPEC to have both IPv4 and IPv6 server */
	hints.ai_flags = AI_PASSIVE;	/* Ready to a bind() socket */
	hints.ai_socktype = SOCK_STREAM;

	/* Warning: this call can be the first one called by the user. */
	/* For this reason, we have to initialize the WinSock support. */
	if (sock_init(errbuf, PCAP_ERRBUF_SIZE) == -1)
		return (SOCKET)-1;

	/* Do the work */
	if ((port == NULL) || (port[0] == 0))
	{
		if (sock_initaddress(address, RPCAP_DEFAULT_NETPORT_ACTIVE, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
		{
			return (SOCKET)-2;
		}
	}
	else
	{
		if (sock_initaddress(address, port, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
		{
			return (SOCKET)-2;
		}
	}


	if ((sockmain = sock_open(addrinfo, SOCKOPEN_SERVER, 1, errbuf, PCAP_ERRBUF_SIZE)) == INVALID_SOCKET)
	{
		freeaddrinfo(addrinfo);
		return (SOCKET)-2;
	}
	freeaddrinfo(addrinfo);

	/* Connection creation */
	fromlen = sizeof(struct sockaddr_storage);

	sockctrl = accept(sockmain, (struct sockaddr *) &from, &fromlen);

	/* We're not using sock_close, since we do not want to send a shutdown */
	/* (which is not allowed on a non-connected socket) */
	closesocket(sockmain);
	sockmain = 0;

	if (sockctrl == INVALID_SOCKET)
	{
		sock_geterror("accept()", errbuf, PCAP_ERRBUF_SIZE);
		return (SOCKET)-2;
	}

	/* Get the numeric for of the name of the connecting host */
	if (getnameinfo((struct sockaddr *) &from, fromlen, connectinghost, RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST))
	{
		sock_geterror("getnameinfo()", errbuf, PCAP_ERRBUF_SIZE);
		rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
		sock_close(sockctrl, NULL, 0);
		return (SOCKET)-1;
	}

	/* checks if the connecting host is among the ones allowed */
	if (sock_check_hostlist((char *)hostlist, RPCAP_HOSTLIST_SEP, &from, errbuf, PCAP_ERRBUF_SIZE) < 0)
	{
		rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
		sock_close(sockctrl, NULL, 0);
		return (SOCKET)-1;
	}

	/*
	 * Send authentication to the remote machine.
	 */
	if (rpcap_doauth(sockctrl, &protocol_version, auth, errbuf) == -1)
	{
		/* Unrecoverable error. */
		rpcap_senderror(sockctrl, 0, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
		sock_close(sockctrl, NULL, 0);
		return (SOCKET)-3;
	}

	/* Checks that this host does not already have a cntrl connection in place */

	/* Initialize pointers */
	temp = activeHosts;
	prev = NULL;

	while (temp)
	{
		/* This host already has an active connection in place, so I don't have to update the host list */
		if (sock_cmpaddr(&temp->host, &from) == 0)
			return sockctrl;

		prev = temp;
		temp = temp->next;
	}

	/* The host does not exist in the list; so I have to update the list */
	if (prev)
	{
		prev->next = (struct activehosts *) malloc(sizeof(struct activehosts));
		temp = prev->next;
	}
	else
	{
		activeHosts = (struct activehosts *) malloc(sizeof(struct activehosts));
		temp = activeHosts;
	}

	if (temp == NULL)
	{
		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
		    errno, "malloc() failed");
		rpcap_senderror(sockctrl, protocol_version, PCAP_ERR_REMOTEACCEPT, errbuf, NULL);
		sock_close(sockctrl, NULL, 0);
		return (SOCKET)-1;
	}

	memcpy(&temp->host, &from, fromlen);
	temp->sockctrl = sockctrl;
	temp->protocol_version = protocol_version;
	temp->next = NULL;

	return sockctrl;
}

int pcap_remoteact_close(const char *host, char *errbuf)
{
	struct activehosts *temp, *prev;	/* temp var needed to scan the host list chain */
	struct addrinfo hints, *addrinfo, *ai_next;	/* temp var needed to translate between hostname to its address */
	int retval;

	temp = activeHosts;
	prev = NULL;

	/* retrieve the network address corresponding to 'host' */
	addrinfo = NULL;
	memset(&hints, 0, sizeof(struct addrinfo));
	hints.ai_family = PF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;

	retval = getaddrinfo(host, "0", &hints, &addrinfo);
	if (retval != 0)
	{
		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "getaddrinfo() %s", gai_strerror(retval));
		return -1;
	}

	while (temp)
	{
		ai_next = addrinfo;
		while (ai_next)
		{
			if (sock_cmpaddr(&temp->host, (struct sockaddr_storage *) ai_next->ai_addr) == 0)
			{
				struct rpcap_header header;
				int status = 0;

				/* Close this connection */
				rpcap_createhdr(&header, temp->protocol_version,
				    RPCAP_MSG_CLOSE, 0, 0);

				/*
				 * Don't check for errors, since we're
				 * just cleaning up.
				 */
				if (sock_send(temp->sockctrl,
				    (char *)&header,
				    sizeof(struct rpcap_header), errbuf,
				    PCAP_ERRBUF_SIZE) < 0)
				{
					/*
					 * Let that error be the one we
					 * report.
					 */
					(void)sock_close(temp->sockctrl, NULL,
					   0);
					status = -1;
				}
				else
				{
					if (sock_close(temp->sockctrl, errbuf,
					   PCAP_ERRBUF_SIZE) == -1)
						status = -1;
				}

				/*
				 * Remove the host from the list of active
				 * hosts.
				 */
				if (prev)
					prev->next = temp->next;
				else
					activeHosts = temp->next;

				freeaddrinfo(addrinfo);

				free(temp);

				/* To avoid inconsistencies in the number of sock_init() */
				sock_cleanup();

				return status;
			}

			ai_next = ai_next->ai_next;
		}
		prev = temp;
		temp = temp->next;
	}

	if (addrinfo)
		freeaddrinfo(addrinfo);

	/* To avoid inconsistencies in the number of sock_init() */
	sock_cleanup();

	pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The host you want to close the active connection is not known");
	return -1;
}

void pcap_remoteact_cleanup(void)
{
	/* Very dirty, but it works */
	if (sockmain)
	{
		closesocket(sockmain);

		/* To avoid inconsistencies in the number of sock_init() */
		sock_cleanup();
	}

}

int pcap_remoteact_list(char *hostlist, char sep, int size, char *errbuf)
{
	struct activehosts *temp;	/* temp var needed to scan the host list chain */
	size_t len;
	char hoststr[RPCAP_HOSTLIST_SIZE + 1];

	temp = activeHosts;

	len = 0;
	*hostlist = 0;

	while (temp)
	{
		/*int sock_getascii_addrport(const struct sockaddr_storage *sockaddr, char *address, int addrlen, char *port, int portlen, int flags, char *errbuf, int errbuflen) */

		/* Get the numeric form of the name of the connecting host */
		if (sock_getascii_addrport((struct sockaddr_storage *) &temp->host, hoststr,
			RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST, errbuf, PCAP_ERRBUF_SIZE) != -1)
			/*	if (getnameinfo( (struct sockaddr *) &temp->host, sizeof (struct sockaddr_storage), hoststr, */
			/*		RPCAP_HOSTLIST_SIZE, NULL, 0, NI_NUMERICHOST) ) */
		{
			/*	sock_geterror("getnameinfo()", errbuf, PCAP_ERRBUF_SIZE); */
			return -1;
		}

		len = len + strlen(hoststr) + 1 /* the separator */;

		if ((size < 0) || (len >= (size_t)size))
		{
			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The string you provided is not able to keep "
				"the hostnames for all the active connections");
			return -1;
		}

		pcap_strlcat(hostlist, hoststr, PCAP_ERRBUF_SIZE);
		hostlist[len - 1] = sep;
		hostlist[len] = 0;

		temp = temp->next;
	}

	return 0;
}

/*
 * Receive the header of a message.
 */
static int rpcap_recv_msg_header(SOCKET sock, struct rpcap_header *header, char *errbuf)
{
	int nrecv;

	nrecv = sock_recv(sock, (char *) header, sizeof(struct rpcap_header),
	    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
	    PCAP_ERRBUF_SIZE);
	if (nrecv == -1)
	{
		/* Network error. */
		return -1;
	}
	header->plen = ntohl(header->plen);
	return 0;
}

/*
 * Make sure the protocol version of a received message is what we were
 * expecting.
 */
static int rpcap_check_msg_ver(SOCKET sock, uint8 expected_ver, struct rpcap_header *header, char *errbuf)
{
	/*
	 * Did the server specify the version we negotiated?
	 */
	if (header->ver != expected_ver)
	{
		/*
		 * Discard the rest of the message.
		 */
		if (rpcap_discard(sock, header->plen, errbuf) == -1)
			return -1;

		/*
		 * Tell our caller that it's not the negotiated version.
		 */
		if (errbuf != NULL)
		{
			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "Server sent us a message with version %u when we were expecting %u",
			    header->ver, expected_ver);
		}
		return -1;
	}
	return 0;
}

/*
 * Check the message type of a received message, which should either be
 * the expected message type or RPCAP_MSG_ERROR.
 */
static int rpcap_check_msg_type(SOCKET sock, uint8 request_type, struct rpcap_header *header, uint16 *errcode, char *errbuf)
{
	const char *request_type_string;
	const char *msg_type_string;

	/*
	 * What type of message is it?
	 */
	if (header->type == RPCAP_MSG_ERROR)
	{
		/*
		 * The server reported an error.
		 * Hand that error back to our caller.
		 */
		*errcode = ntohs(header->value);
		rpcap_msg_err(sock, header->plen, errbuf);
		return -1;
	}

	*errcode = 0;

	/*
	 * For a given request type value, the expected reply type value
	 * is the request type value with ORed with RPCAP_MSG_IS_REPLY.
	 */
	if (header->type != (request_type | RPCAP_MSG_IS_REPLY))
	{
		/*
		 * This isn't a reply to the request we sent.
		 */

		/*
		 * Discard the rest of the message.
		 */
		if (rpcap_discard(sock, header->plen, errbuf) == -1)
			return -1;

		/*
		 * Tell our caller about it.
		 */
		request_type_string = rpcap_msg_type_string(request_type);
		msg_type_string = rpcap_msg_type_string(header->type);
		if (errbuf != NULL)
		{
			if (request_type_string == NULL)
			{
				/* This should not happen. */
				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
				    "rpcap_check_msg_type called for request message with type %u",
				    request_type);
				return -1;
			}
			if (msg_type_string != NULL)
				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
				    "%s message received in response to a %s message",
				    msg_type_string, request_type_string);
			else
				pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
				    "Message of unknown type %u message received in response to a %s request",
				    header->type, request_type_string);
		}
		return -1;
	}

	return 0;
}

/*
 * Receive and process the header of a message.
 */
static int rpcap_process_msg_header(SOCKET sock, uint8 expected_ver, uint8 request_type, struct rpcap_header *header, char *errbuf)
{
	uint16 errcode;

	if (rpcap_recv_msg_header(sock, header, errbuf) == -1)
	{
		/* Network error. */
		return -1;
	}

	/*
	 * Did the server specify the version we negotiated?
	 */
	if (rpcap_check_msg_ver(sock, expected_ver, header, errbuf) == -1)
		return -1;

	/*
	 * Check the message type.
	 */
	return rpcap_check_msg_type(sock, request_type, header,
	    &errcode, errbuf);
}

/*
 * Read data from a message.
 * If we're trying to read more data that remains, puts an error
 * message into errmsgbuf and returns -2.  Otherwise, tries to read
 * the data and, if that succeeds, subtracts the amount read from
 * the number of bytes of data that remains.
 * Returns 0 on success, logs a message and returns -1 on a network
 * error.
 */
static int rpcap_recv(SOCKET sock, void *buffer, size_t toread, uint32 *plen, char *errbuf)
{
	int nread;

	if (toread > *plen)
	{
		/* The server sent us a bad message */
		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Message payload is too short");
		return -1;
	}
	nread = sock_recv(sock, buffer, toread,
	    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf, PCAP_ERRBUF_SIZE);
	if (nread == -1)
	{
		return -1;
	}
	*plen -= nread;
	return 0;
}

/*
 * This handles the RPCAP_MSG_ERROR message.
 */
static void rpcap_msg_err(SOCKET sockctrl, uint32 plen, char *remote_errbuf)
{
	char errbuf[PCAP_ERRBUF_SIZE];

	if (plen >= PCAP_ERRBUF_SIZE)
	{
		/*
		 * Message is too long; just read as much of it as we
		 * can into the buffer provided, and discard the rest.
		 */
		if (sock_recv(sockctrl, remote_errbuf, PCAP_ERRBUF_SIZE - 1,
		    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
		    PCAP_ERRBUF_SIZE) == -1)
		{
			// Network error.
			pcap_snprintf(remote_errbuf, PCAP_ERRBUF_SIZE, "Read of error message from client failed: %s", errbuf);
			return;
		}

		/*
		 * Null-terminate it.
		 */
		remote_errbuf[PCAP_ERRBUF_SIZE - 1] = '\0';

		/*
		 * Throw away the rest.
		 */
		(void)rpcap_discard(sockctrl, plen - (PCAP_ERRBUF_SIZE - 1), remote_errbuf);
	}
	else if (plen == 0)
	{
		/* Empty error string. */
		remote_errbuf[0] = '\0';
	}
	else
	{
		if (sock_recv(sockctrl, remote_errbuf, plen,
		    SOCK_RECEIVEALL_YES|SOCK_EOF_IS_ERROR, errbuf,
		    PCAP_ERRBUF_SIZE) == -1)
		{
			// Network error.
			pcap_snprintf(remote_errbuf, PCAP_ERRBUF_SIZE, "Read of error message from client failed: %s", errbuf);
			return;
		}

		/*
		 * Null-terminate it.
		 */
		remote_errbuf[plen] = '\0';
	}
}

/*
 * Discard data from a connection.
 * Mostly used to discard wrong-sized messages.
 * Returns 0 on success, logs a message and returns -1 on a network
 * error.
 */
static int rpcap_discard(SOCKET sock, uint32 len, char *errbuf)
{
	if (len != 0)
	{
		if (sock_discard(sock, len, errbuf, PCAP_ERRBUF_SIZE) == -1)
		{
			// Network error.
			return -1;
		}
	}
	return 0;
}

/*
 * Read bytes into the pcap_t's buffer until we have the specified
 * number of bytes read or we get an error or interrupt indication.
 */
static int rpcap_read_packet_msg(SOCKET sock, pcap_t *p, size_t size)
{
	u_char *bp;
	int cc;
	int bytes_read;

	bp = p->bp;
	cc = p->cc;

	/*
	 * Loop until we have the amount of data requested or we get
	 * an error or interrupt.
	 */
	while ((size_t)cc < size)
	{
		/*
		 * We haven't read all of the packet header yet.
		 * Read what remains, which could be all of it.
		 */
		bytes_read = sock_recv(sock, bp, size - cc,
		    SOCK_RECEIVEALL_NO|SOCK_EOF_IS_ERROR, p->errbuf,
		    PCAP_ERRBUF_SIZE);
		if (bytes_read == -1)
		{
			/*
			 * Network error.  Update the read pointer and
			 * byte count, and return an error indication.
			 */
			p->bp = bp;
			p->cc = cc;
			return -1;
		}
		if (bytes_read == -3)
		{
			/*
			 * Interrupted receive.  Update the read
			 * pointer and byte count, and return
			 * an interrupted indication.
			 */
			p->bp = bp;
			p->cc = cc;
			return -3;
		}
		if (bytes_read == 0)
		{
			/*
			 * EOF - server terminated the connection.
			 * Update the read pointer and byte count, and
			 * return an error indication.
			 */
			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
			    "The server terminated the connection.");
			return -1;
		}
		bp += bytes_read;
		cc += bytes_read;
	}
	p->bp = bp;
	p->cc = cc;
	return 0;
}