/*

 * Copyright (c) 2011 Jakub Zawadzki

 * 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. The name of the author may not 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 "pcap-int.h"

#ifdef NEED_STRERROR_H

#include "strerror.h"

#endif

#include <errno.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <time.h>

#include <sys/time.h>

#include <netinet/in.h>

#include <linux/types.h>

#include <linux/netlink.h>

#include <linux/netfilter.h>

#include <linux/netfilter/nfnetlink.h>

#include <linux/netfilter/nfnetlink_log.h>

#include <linux/netfilter/nfnetlink_queue.h>

/* NOTE: if your program drops privilages after pcap_activate() it WON'T work with nfqueue.

 *       It took me quite some time to debug ;/

 *

 *       Sending any data to nfnetlink socket requires CAP_NET_ADMIN privilages,

 *       and in nfqueue we need to send verdict reply after recving packet.

 *

 *       In tcpdump you can disable dropping privilages with -Z root

 */

#include "pcap-netfilter-linux.h"

#define HDR_LENGTH (NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg))))

#define NFLOG_IFACE "nflog"

#define NFQUEUE_IFACE "nfqueue"

typedef enum { OTHER = -1, NFLOG, NFQUEUE } nftype_t;

/*

 * Private data for capturing on Linux netfilter sockets.

 */

struct pcap_netfilter {

	u_int	packets_read;	/* count of packets read with recvfrom() */

	u_int   packets_nobufs; /* ENOBUFS counter */

};

static int nfqueue_send_verdict(const pcap_t *handle, uint16_t group_id, u_int32_t id, u_int32_t verdict);

static int

netfilter_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)

{

	struct pcap_netfilter *handlep = handle->priv;

	register u_char *bp, *ep;

	int count = 0;

	int len;

	/*

	 * Has "pcap_breakloop()" been called?

	 */

	if (handle->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.

		 */

		handle->break_loop = 0;

		return PCAP_ERROR_BREAK;

	}

	len = handle->cc;

	if (len == 0) {

		/*

		 * The buffer is empty; refill it.

		 *

		 * We ignore EINTR, as that might just be due to a signal

		 * being delivered - if the signal should interrupt the

		 * loop, the signal handler should call pcap_breakloop()

		 * to set handle->break_loop (we ignore it on other

		 * platforms as well).

		 */

		do {

			len = recv(handle->fd, handle->buffer, handle->bufsize, 0);

			if (handle->break_loop) {

				handle->break_loop = 0;

				return PCAP_ERROR_BREAK;

			}

			if (errno == ENOBUFS)

				handlep->packets_nobufs++;

		} while ((len == -1) && (errno == EINTR || errno == ENOBUFS));

		if (len < 0) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno, "Can't receive packet");

			return PCAP_ERROR;

		}

		bp = (unsigned char *)handle->buffer;

	} else

		bp = handle->bp;

	ep = bp + len;

	while (bp < ep) {

		const struct nlmsghdr *nlh = (const struct nlmsghdr *) bp;

		uint32_t msg_len;

		nftype_t type = OTHER;

		/*

		 * Has "pcap_breakloop()" been called?

		 * If so, return immediately - if we haven't read any

		 * packets, clear the flag and return PCAP_ERROR_BREAK

		 * to indicate that we were told to break out of the loop,

		 * otherwise leave the flag set, so that the *next* call

		 * will break out of the loop without having read any

		 * packets, and return the number of packets we've

		 * processed so far.

		 */

		if (handle->break_loop) {

			handle->bp = bp;

			handle->cc = ep - bp;

			if (count == 0) {

				handle->break_loop = 0;

				return PCAP_ERROR_BREAK;

			} else

				return count;

		}

		if (ep - bp < NLMSG_SPACE(0)) {

			/*

			 * There's less than one netlink message left

			 * in the buffer.  Give up.

			 */

			break;

		}

		if (nlh->nlmsg_len < sizeof(struct nlmsghdr) || (u_int)len < nlh->nlmsg_len) {

			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Message truncated: (got: %d) (nlmsg_len: %u)", len, nlh->nlmsg_len);

			return -1;

		}

		if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG &&

		    NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET)

			type = NFLOG;

		else if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_QUEUE &&

		         NFNL_MSG_TYPE(nlh->nlmsg_type) == NFQNL_MSG_PACKET)

			type = NFQUEUE;

		if (type != OTHER) {

			const unsigned char *payload = NULL;

			struct pcap_pkthdr pkth;

			const struct nfgenmsg *nfg = NULL;

			int id = 0;

			if (handle->linktype != DLT_NFLOG) {

				const struct nfattr *payload_attr = NULL;

				if (nlh->nlmsg_len < HDR_LENGTH) {

					pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Malformed message: (nlmsg_len: %u)", nlh->nlmsg_len);

					return -1;

				}

				nfg = NLMSG_DATA(nlh);

				if (nlh->nlmsg_len > HDR_LENGTH) {

					struct nfattr *attr = NFM_NFA(nfg);

					int attr_len = nlh->nlmsg_len - NLMSG_ALIGN(HDR_LENGTH);

					while (NFA_OK(attr, attr_len)) {

						if (type == NFQUEUE) {

							switch (NFA_TYPE(attr)) {

								case NFQA_PACKET_HDR:

									{

										const struct nfqnl_msg_packet_hdr *pkt_hdr = (const struct nfqnl_msg_packet_hdr *) NFA_DATA(attr);

										id = ntohl(pkt_hdr->packet_id);

										break;

									}

								case NFQA_PAYLOAD:

									payload_attr = attr;

									break;

							}

						} else if (type == NFLOG) {

							switch (NFA_TYPE(attr)) {

								case NFULA_PAYLOAD:

									payload_attr = attr;

									break;

							}

						}

						attr = NFA_NEXT(attr, attr_len);

					}

				}

				if (payload_attr) {

					payload = NFA_DATA(payload_attr);

					pkth.len = pkth.caplen = NFA_PAYLOAD(payload_attr);

				}

			} else {

				payload = NLMSG_DATA(nlh);

				pkth.caplen = pkth.len = nlh->nlmsg_len-NLMSG_ALIGN(sizeof(struct nlmsghdr));

			}

			if (payload) {

				/* pkth.caplen = min (payload_len, handle->snapshot); */

				gettimeofday(&pkth.ts, NULL);

				if (handle->fcode.bf_insns == NULL ||

						bpf_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen))

				{

					handlep->packets_read++;

					callback(user, &pkth, payload);

					count++;

				}

			}

			if (type == NFQUEUE) {

				/* XXX, possible responses: NF_DROP, NF_ACCEPT, NF_STOLEN, NF_QUEUE, NF_REPEAT, NF_STOP */

				/* if type == NFQUEUE, handle->linktype is always != DLT_NFLOG,

				   so nfg is always initialized to NLMSG_DATA(nlh). */

				if (nfg != NULL)

					nfqueue_send_verdict(handle, ntohs(nfg->res_id), id, NF_ACCEPT);

			}

		}

		msg_len = NLMSG_ALIGN(nlh->nlmsg_len);

		/*

		 * If the message length would run past the end of the

		 * buffer, truncate it to the remaining space in the

		 * buffer.

		 */

		if (msg_len > ep - bp)

			msg_len = ep - bp;

		bp += msg_len;

		if (count >= max_packets && !PACKET_COUNT_IS_UNLIMITED(max_packets)) {

			handle->bp = bp;

			handle->cc = ep - bp;

			if (handle->cc < 0)

				handle->cc = 0;

			return count;

		}

	}

	handle->cc = 0;

	return count;

}

static int

netfilter_set_datalink(pcap_t *handle, int dlt)

{

	handle->linktype = dlt;

	return 0;

}

static int

netfilter_stats_linux(pcap_t *handle, struct pcap_stat *stats)

{

	struct pcap_netfilter *handlep = handle->priv;

	stats->ps_recv = handlep->packets_read;

	stats->ps_drop = handlep->packets_nobufs;

	stats->ps_ifdrop = 0;

	return 0;

}

static int

netfilter_inject_linux(pcap_t *handle, const void *buf _U_, size_t size _U_)

{

	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,

	    "Packet injection is not supported on netfilter devices");

	return (-1);

}

struct my_nfattr {

	uint16_t nfa_len;

	uint16_t nfa_type;

	void *data;

};

static int

netfilter_send_config_msg(const pcap_t *handle, uint16_t msg_type, int ack, u_int8_t family, u_int16_t res_id, const struct my_nfattr *mynfa)

{

	char buf[1024] __attribute__ ((aligned));

	memset(buf, 0, sizeof(buf));

	struct nlmsghdr *nlh = (struct nlmsghdr *) buf;

	struct nfgenmsg *nfg = (struct nfgenmsg *) (buf + sizeof(struct nlmsghdr));

	struct sockaddr_nl snl;

	static unsigned int seq_id;

	if (!seq_id)

		seq_id = time(NULL);

	++seq_id;

	nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nfgenmsg));

	nlh->nlmsg_type = msg_type;

	nlh->nlmsg_flags = NLM_F_REQUEST | (ack ? NLM_F_ACK : 0);

	nlh->nlmsg_pid = 0;	/* to kernel */

	nlh->nlmsg_seq = seq_id;

	nfg->nfgen_family = family;

	nfg->version = NFNETLINK_V0;

	nfg->res_id = htons(res_id);

	if (mynfa) {

		struct nfattr *nfa = (struct nfattr *) (buf + NLMSG_ALIGN(nlh->nlmsg_len));

		nfa->nfa_type = mynfa->nfa_type;

		nfa->nfa_len = NFA_LENGTH(mynfa->nfa_len);

		memcpy(NFA_DATA(nfa), mynfa->data, mynfa->nfa_len);

		nlh->nlmsg_len = NLMSG_ALIGN(nlh->nlmsg_len) + NFA_ALIGN(nfa->nfa_len);

	}

	memset(&snl, 0, sizeof(snl));

	snl.nl_family = AF_NETLINK;

	if (sendto(handle->fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr *) &snl, sizeof(snl)) == -1)

		return -1;

	if (!ack)

		return 0;

	/* waiting for reply loop */

	do {

		socklen_t addrlen = sizeof(snl);

		int len;

		/* ignore interrupt system call error */

		do {

			len = recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen);

		} while ((len == -1) && (errno == EINTR));

		if (len <= 0)

			return len;

		if (addrlen != sizeof(snl) || snl.nl_family != AF_NETLINK) {

			errno = EINVAL;

			return -1;

		}

		nlh = (struct nlmsghdr *) buf;

		if (snl.nl_pid != 0 || seq_id != nlh->nlmsg_seq)	/* if not from kernel or wrong sequence skip */

			continue;

		while ((u_int)len >= NLMSG_SPACE(0) && NLMSG_OK(nlh, (u_int)len)) {

			if (nlh->nlmsg_type == NLMSG_ERROR || (nlh->nlmsg_type == NLMSG_DONE && nlh->nlmsg_flags & NLM_F_MULTI)) {

				if (nlh->nlmsg_len < NLMSG_ALIGN(sizeof(struct nlmsgerr))) {

					errno = EBADMSG;

					return -1;

				}

				errno = -(*((int *)NLMSG_DATA(nlh)));

				return (errno == 0) ? 0 : -1;

			}

			nlh = NLMSG_NEXT(nlh, len);

		}

	} while (1);

	return -1; /* never here */

}

static int

nflog_send_config_msg(const pcap_t *handle, uint8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)

{

	return netfilter_send_config_msg(handle, (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG, 1, family, group_id, mynfa);

}

static int

nflog_send_config_cmd(const pcap_t *handle, uint16_t group_id, u_int8_t cmd, u_int8_t family)

{

	struct nfulnl_msg_config_cmd msg;

	struct my_nfattr nfa;

	msg.command = cmd;

	nfa.data = &msg;

	nfa.nfa_type = NFULA_CFG_CMD;

	nfa.nfa_len = sizeof(msg);

	return nflog_send_config_msg(handle, family, group_id, &nfa;;

}

static int

nflog_send_config_mode(const pcap_t *handle, uint16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)

{

	struct nfulnl_msg_config_mode msg;

	struct my_nfattr nfa;

	msg.copy_range = htonl(copy_range);

	msg.copy_mode = copy_mode;

	nfa.data = &msg;

	nfa.nfa_type = NFULA_CFG_MODE;

	nfa.nfa_len = sizeof(msg);

	return nflog_send_config_msg(handle, AF_UNSPEC, group_id, &nfa;;

}

static int

nfqueue_send_verdict(const pcap_t *handle, uint16_t group_id, u_int32_t id, u_int32_t verdict)

{

	struct nfqnl_msg_verdict_hdr msg;

	struct my_nfattr nfa;

	msg.id = htonl(id);

	msg.verdict = htonl(verdict);

	nfa.data = &msg;

	nfa.nfa_type = NFQA_VERDICT_HDR;

	nfa.nfa_len = sizeof(msg);

	return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT, 0, AF_UNSPEC, group_id, &nfa;;

}

static int

nfqueue_send_config_msg(const pcap_t *handle, uint8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)

{

	return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG, 1, family, group_id, mynfa);

}

static int

nfqueue_send_config_cmd(const pcap_t *handle, uint16_t group_id, u_int8_t cmd, u_int16_t pf)

{

	struct nfqnl_msg_config_cmd msg;

	struct my_nfattr nfa;

	msg.command = cmd;

	msg.pf = htons(pf);

	nfa.data = &msg;

	nfa.nfa_type = NFQA_CFG_CMD;

	nfa.nfa_len = sizeof(msg);

	return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa;;

}

static int

nfqueue_send_config_mode(const pcap_t *handle, uint16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)

{

	struct nfqnl_msg_config_params msg;

	struct my_nfattr nfa;

	msg.copy_range = htonl(copy_range);

	msg.copy_mode = copy_mode;

	nfa.data = &msg;

	nfa.nfa_type = NFQA_CFG_PARAMS;

	nfa.nfa_len = sizeof(msg);

	return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa;;

}

static int

netfilter_activate(pcap_t* handle)

{

	const char *dev = handle->opt.device;

	unsigned short groups[32];

	int group_count = 0;

	nftype_t type = OTHER;

	int i;

 	if (strncmp(dev, NFLOG_IFACE, strlen(NFLOG_IFACE)) == 0) {

 		dev += strlen(NFLOG_IFACE);

		type = NFLOG;

	} else if (strncmp(dev, NFQUEUE_IFACE, strlen(NFQUEUE_IFACE)) == 0) {

		dev += strlen(NFQUEUE_IFACE);

		type = NFQUEUE;

	}

	if (type != OTHER && *dev == ':') {

		dev++;

		while (*dev) {

			long int group_id;

			char *end_dev;

			if (group_count == 32) {

				pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,

						"Maximum 32 netfilter groups! dev: %s",

						handle->opt.device);

				return PCAP_ERROR;

			}

			group_id = strtol(dev, &end_dev, 0);

			if (end_dev != dev) {

				if (group_id < 0 || group_id > 65535) {

					pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,

							"Netfilter group range from 0 to 65535 (got %ld)",

							group_id);

					return PCAP_ERROR;

				}

				groups[group_count++] = (unsigned short) group_id;

				dev = end_dev;

			}

			if (*dev != ',')

				break;

			dev++;

		}

	}

	if (type == OTHER || *dev) {

		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,

				"Can't get netfilter group(s) index from %s",

				handle->opt.device);

		return PCAP_ERROR;

	}

	/* if no groups, add default: 0 */

	if (!group_count) {

		groups[0] = 0;

		group_count = 1;

	}

	/*

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

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

	 * value, into the maximum allowed value.

	 *

	 * If some application really *needs* a bigger snapshot

	 * length, we should just increase MAXIMUM_SNAPLEN.

	 */

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

		handle->snapshot = MAXIMUM_SNAPLEN;

	/* Initialize some components of the pcap structure. */

	handle->bufsize = 128 + handle->snapshot;

	handle->offset = 0;

	handle->read_op = netfilter_read_linux;

	handle->inject_op = netfilter_inject_linux;

	handle->setfilter_op = install_bpf_program; /* no kernel filtering */

	handle->setdirection_op = NULL;

	handle->set_datalink_op = netfilter_set_datalink;

	handle->getnonblock_op = pcap_getnonblock_fd;

	handle->setnonblock_op = pcap_setnonblock_fd;

	handle->stats_op = netfilter_stats_linux;

	/* Create netlink socket */

	handle->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);

	if (handle->fd < 0) {

		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "Can't create raw socket");

		return PCAP_ERROR;

	}

	if (type == NFLOG) {

		handle->linktype = DLT_NFLOG;

		handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);

		if (handle->dlt_list != NULL) {

			handle->dlt_list[0] = DLT_NFLOG;

			handle->dlt_list[1] = DLT_IPV4;

			handle->dlt_count = 2;

		}

	} else

		handle->linktype = DLT_IPV4;

	handle->buffer = malloc(handle->bufsize);

	if (!handle->buffer) {

		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,

		    errno, "Can't allocate dump buffer");

		goto close_fail;

	}

	if (type == NFLOG) {

		if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno,

			    "NFULNL_CFG_CMD_PF_UNBIND");

			goto close_fail;

		}

		if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_BIND, AF_INET) < 0) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno, "NFULNL_CFG_CMD_PF_BIND");

			goto close_fail;

		}

		/* Bind socket to the nflog groups */

		for (i = 0; i < group_count; i++) {

			if (nflog_send_config_cmd(handle, groups[i], NFULNL_CFG_CMD_BIND, AF_UNSPEC) < 0) {

				pcap_fmt_errmsg_for_errno(handle->errbuf,

				    PCAP_ERRBUF_SIZE, errno,

				    "Can't listen on group group index");

				goto close_fail;

			}

			if (nflog_send_config_mode(handle, groups[i], NFULNL_COPY_PACKET, handle->snapshot) < 0) {

				pcap_fmt_errmsg_for_errno(handle->errbuf,

				    PCAP_ERRBUF_SIZE, errno,

				    "NFULNL_COPY_PACKET");

				goto close_fail;

			}

		}

	} else {

		if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno, "NFQNL_CFG_CMD_PF_UNBIND");

			goto close_fail;

		}

		if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_BIND, AF_INET) < 0) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno, "NFQNL_CFG_CMD_PF_BIND");

			goto close_fail;

		}

		/* Bind socket to the nfqueue groups */

		for (i = 0; i < group_count; i++) {

			if (nfqueue_send_config_cmd(handle, groups[i], NFQNL_CFG_CMD_BIND, AF_UNSPEC) < 0) {

				pcap_fmt_errmsg_for_errno(handle->errbuf,

				    PCAP_ERRBUF_SIZE, errno,

				    "Can't listen on group group index");

				goto close_fail;

			}

			if (nfqueue_send_config_mode(handle, groups[i], NFQNL_COPY_PACKET, handle->snapshot) < 0) {

				pcap_fmt_errmsg_for_errno(handle->errbuf,

				    PCAP_ERRBUF_SIZE, errno,

				    "NFQNL_COPY_PACKET");

				goto close_fail;

			}

		}

	}

	if (handle->opt.rfmon) {

		/*

		 * Monitor mode doesn't apply to netfilter devices.

		 */

		pcap_cleanup_live_common(handle);

		return PCAP_ERROR_RFMON_NOTSUP;

	}

	if (handle->opt.buffer_size != 0) {

		/*

		 * Set the socket buffer size to the specified value.

		 */

		if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF, &handle->opt.buffer_size, sizeof(handle->opt.buffer_size)) == -1) {

			pcap_fmt_errmsg_for_errno(handle->errbuf,

			    PCAP_ERRBUF_SIZE, errno, "SO_RCVBUF");

			goto close_fail;

		}

	}

	handle->selectable_fd = handle->fd;

	return 0;

close_fail:

	pcap_cleanup_live_common(handle);

	return PCAP_ERROR;

}

pcap_t *

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

{

	const char *cp;

	pcap_t *p;

	/* Does this look like an netfilter device? */

	cp = strrchr(device, '/');

	if (cp == NULL)

		cp = device;

	/* Does it begin with NFLOG_IFACE or NFQUEUE_IFACE? */

	if (strncmp(cp, NFLOG_IFACE, sizeof NFLOG_IFACE - 1) == 0)

		cp += sizeof NFLOG_IFACE - 1;

	else if (strncmp(cp, NFQUEUE_IFACE, sizeof NFQUEUE_IFACE - 1) == 0)

		cp += sizeof NFQUEUE_IFACE - 1;

	else {

		/* Nope, doesn't begin with NFLOG_IFACE nor NFQUEUE_IFACE */

		*is_ours = 0;

		return NULL;

	}

	/*

	 * Yes - is that either the end of the name, or is it followed

	 * by a colon?

	 */

	if (*cp != ':' && *cp != '\0') {

		/* Nope */

		*is_ours = 0;

		return NULL;

	}

	/* OK, it's probably ours. */

	*is_ours = 1;

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

	if (p == NULL)

		return (NULL);

	p->activate_op = netfilter_activate;

	return (p);

}

int

netfilter_findalldevs(pcap_if_list_t *devlistp, char *err_str)

{

	int sock;

	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);

	if (sock < 0) {

		/* if netlink is not supported this is not fatal */

		if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT)

			return 0;

		pcap_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,

		    errno, "Can't open netlink socket");

		return -1;

	}

	close(sock);

	/*

	 * The notion of "connected" vs. "disconnected" doesn't apply.

	 * XXX - what about "up" and "running"?

	 */

	if (add_dev(devlistp, NFLOG_IFACE,

	    PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,

	    "Linux netfilter log (NFLOG) interface", err_str) == NULL)

		return -1;

	if (add_dev(devlistp, NFQUEUE_IFACE,

	    PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,

	    "Linux netfilter queue (NFQUEUE) interface", err_str) == NULL)

		return -1;

	return 0;

}