/*
 *
 *  Wireless daemon for Linux
 *
 *  Copyright (C) 2013-2019  Intel Corporation. All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <signal.h>
#include <sys/socket.h>
#include <linux/genetlink.h>
#include <linux/rtnetlink.h>
#include <linux/if_arp.h>
#include <ell/ell.h>

#ifndef ARPHRD_NETLINK
#define ARPHRD_NETLINK	824
#endif

#include "linux/nl80211.h"
#include "monitor/nlmon.h"
#include "monitor/pcap.h"
#include "monitor/display.h"

#define MAX_SNAPLEN (1024 * 16)

static struct nlmon *nlmon = NULL;
static const char *writer_path = NULL;
static struct l_timeout *timeout = NULL;
static struct nlmon_config config;

#define NLA_OK(nla,len)         ((len) >= (int) sizeof(struct nlattr) && \
				(nla)->nla_len >= sizeof(struct nlattr) && \
				(nla)->nla_len <= (len))
#define NLA_NEXT(nla,attrlen)	((attrlen) -= NLA_ALIGN((nla)->nla_len), \
				(struct nlattr*)(((char*)(nla)) + \
				NLA_ALIGN((nla)->nla_len)))

#define NLA_LENGTH(len)		(NLA_ALIGN(sizeof(struct nlattr)) + (len))
#define NLA_DATA(nla)		((void*)(((char*)(nla)) + NLA_LENGTH(0)))
#define NLA_PAYLOAD(nla)	((int)((nla)->nla_len - NLA_LENGTH(0)))

#define NLMON_TYPE "nlmon"
#define NLMON_LEN  5

struct iwmon_interface {
	char *ifname;
	bool exists;
	struct l_netlink *rtnl;
	struct l_netlink *genl;
};

static struct iwmon_interface monitor_interface = { };

static void genl_parse(uint16_t type, const void *data, uint32_t len,
							const char *ifname)
{
	const struct genlmsghdr *genlmsg = data;
	const struct nlattr *nla;
	char name[GENL_NAMSIZ];
	uint16_t id = 0;

	if (nlmon)
		return;

	if (type != GENL_ID_CTRL)
		return;

	if (genlmsg->cmd != CTRL_CMD_NEWFAMILY)
		return;

	for (nla = data + GENL_HDRLEN; NLA_OK(nla, len);
						nla = NLA_NEXT(nla, len)) {
		switch (nla->nla_type & NLA_TYPE_MASK) {
		case CTRL_ATTR_FAMILY_ID:
			id = *((uint16_t *) NLA_DATA(nla));
			break;
		case CTRL_ATTR_FAMILY_NAME:
			strncpy(name, NLA_DATA(nla), GENL_NAMSIZ - 1);
			break;
		}
	}

	if (id == 0)
		return;

	if (!strcmp(name, NL80211_GENL_NAME)) {
		nlmon = nlmon_open(ifname, id, writer_path, &config);
		if (!nlmon)
			l_main_quit();
	}
}

static void genl_notify(uint16_t type, const void *data,
						uint32_t len, void *user_data)
{
	const char *ifname = user_data;

	genl_parse(type, data, len, ifname);
}

static void genl_callback(int error, uint16_t type, const void *data,
						uint32_t len, void *user_data)
{
	const char *ifname = user_data;

	if (error < 0) {
		fprintf(stderr, "Failed to lookup nl80211 family\n");
		l_main_quit();
		return;
	}

	genl_parse(type, data, len, ifname);
}

static struct l_netlink *genl_lookup(const char *ifname)
{
	struct l_netlink *genl;
	char buf[GENL_HDRLEN + NLA_HDRLEN + GENL_NAMSIZ];
	struct genlmsghdr *genlmsg;
	struct nlattr *nla;

	genl = l_netlink_new(NETLINK_GENERIC);

	l_netlink_register(genl, GENL_ID_CTRL, genl_notify, NULL, NULL);

	genlmsg = (struct genlmsghdr *) buf;
	genlmsg->cmd = CTRL_CMD_GETFAMILY;
	genlmsg->version = 0;
	genlmsg->reserved = 0;

	nla = (struct nlattr *) (buf + GENL_HDRLEN);
	nla->nla_len = NLA_HDRLEN + GENL_NAMSIZ;
	nla->nla_type = CTRL_ATTR_FAMILY_NAME;
	strncpy(buf + GENL_HDRLEN + NLA_HDRLEN,
					NL80211_GENL_NAME, GENL_NAMSIZ);

	l_netlink_send(genl, GENL_ID_CTRL, 0, buf, sizeof(buf),
					genl_callback, (char *) ifname, NULL);

	return genl;
}

static size_t rta_add(void *rta_buf, unsigned short type, uint16_t len,
			const void *data)
{
	unsigned short rta_len = RTA_LENGTH(len);
	struct rtattr *rta = rta_buf;

	memset(RTA_DATA(rta), 0, RTA_SPACE(len));

	rta->rta_len = rta_len;
	rta->rta_type = type;
	if (len)
		memcpy(RTA_DATA(rta), data, len);

	return RTA_SPACE(len);
}

static bool rta_linkinfo_kind(struct rtattr *rta, unsigned short len,
			const char* kind)
{
	for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
		if (rta->rta_type != IFLA_INFO_KIND)
			continue;

		if (rta->rta_len < NLMON_LEN)
			continue;

		if (memcmp(RTA_DATA(rta), kind, strlen(kind)))
			continue;

		return true;
	}

	return false;
}

static struct l_netlink *rtm_interface_send_message(struct l_netlink *rtnl,
					const char *ifname,
					uint16_t rtm_msg_type,
					l_netlink_command_func_t callback,
					void *user_data,
					l_netlink_destroy_func_t destroy)
{
	size_t nlmon_type_len = strlen(NLMON_TYPE);
	unsigned short ifname_len = 0;
	size_t bufsize;
	struct ifinfomsg *rtmmsg;
	void *rta_buf;
	struct rtattr *linkinfo_rta;

	if (ifname) {
		ifname_len = strlen(ifname) + 1;

		if (ifname_len < 2 || ifname_len > IFNAMSIZ)
			return NULL;
	}

	if (!rtnl)
		rtnl = l_netlink_new(NETLINK_ROUTE);

	if (!rtnl)
		return NULL;

	bufsize = NLMSG_LENGTH(sizeof(struct ifinfomsg)) +
		RTA_SPACE(ifname_len) + RTA_SPACE(0) +
		RTA_SPACE(nlmon_type_len);

	rtmmsg = l_malloc(bufsize);
	memset(rtmmsg, 0, bufsize);

	rtmmsg->ifi_family = AF_UNSPEC;
	rtmmsg->ifi_change = ~0;

	rta_buf = rtmmsg + 1;

	if (ifname)
		rta_buf += rta_add(rta_buf, IFLA_IFNAME, ifname_len, ifname);

	linkinfo_rta = rta_buf;

	rta_buf += rta_add(rta_buf, IFLA_LINKINFO, 0, NULL);
	rta_buf += rta_add(rta_buf, IFLA_INFO_KIND, nlmon_type_len, NLMON_TYPE);

	linkinfo_rta->rta_len = rta_buf - (void *) linkinfo_rta;

	switch (rtm_msg_type) {
	case RTM_NEWLINK:
		rtmmsg->ifi_flags = IFF_UP | IFF_ALLMULTI | IFF_NOARP;

		l_netlink_send(rtnl, RTM_NEWLINK, NLM_F_CREATE|NLM_F_EXCL,
				rtmmsg, rta_buf - (void *) rtmmsg, callback,
				user_data, destroy);
		break;

	case RTM_DELLINK:
		rta_buf += rta_add(rta_buf, IFLA_IFNAME, ifname_len, ifname);

		l_netlink_send(rtnl, RTM_DELLINK, 0, rtmmsg,
				rta_buf - (void *)rtmmsg, callback, user_data,
				destroy);
		break;

	case RTM_GETLINK:
		l_netlink_send(rtnl, RTM_GETLINK, NLM_F_DUMP, rtmmsg,
				rta_buf - (void *)rtmmsg, callback, user_data,
				destroy);
		break;

	default:
		l_netlink_destroy(rtnl);
		rtnl = NULL;
		break;
	}

	l_free(rtmmsg);

	return rtnl;
}

static struct l_netlink *iwmon_interface_disable(
				struct iwmon_interface *monitor_interface)
{
	if (!monitor_interface->exists)
		return rtm_interface_send_message(monitor_interface->rtnl,
						monitor_interface->ifname,
						RTM_DELLINK, NULL, NULL, NULL);

	return monitor_interface->rtnl;
}

static void iwmon_interface_enable_callback(int error, uint16_t type,
						const void *data, uint32_t len,
						void *user_data)
{
	struct iwmon_interface *monitor_interface = user_data;

	if (error) {
		fprintf(stderr, "Failed to create monitor interface %s: %s\n",
			monitor_interface->ifname, strerror(error));

		l_main_quit();
		return;
	}

	printf("Created interface %s\n", monitor_interface->ifname);

	monitor_interface->genl = genl_lookup(monitor_interface->ifname);
}

static struct l_netlink *iwmon_interface_enable(
				struct iwmon_interface *monitor_interface)
{
	return rtm_interface_send_message(monitor_interface->rtnl,
						monitor_interface->ifname,
						RTM_NEWLINK,
						iwmon_interface_enable_callback,
						monitor_interface, NULL);
}

static void iwmon_interface_lookup_done(void *user_data)
{
	struct iwmon_interface *monitor_interface = user_data;

	if (monitor_interface->exists && monitor_interface->ifname) {
		printf("Using %s as Monitor interface\n",
			monitor_interface->ifname);

		monitor_interface->genl =
			genl_lookup(monitor_interface->ifname);

		return;
	}

	if (!monitor_interface->ifname)
		monitor_interface->ifname = l_strdup(NLMON_TYPE);

	iwmon_interface_enable(monitor_interface);
}

static void iwmon_interface_lookup_callback(int error, uint16_t type,
						const void *data, uint32_t len,
						void *user_data)
{
	const struct ifinfomsg *rtmmsg = data;
	struct rtattr *rta;
	struct iwmon_interface *monitor_interface = user_data;
	const char *ifname = NULL;
	unsigned short ifname_len = 0;
	bool nlmon = false;

	if (error)
		return;

	if (type != RTM_NEWLINK)
		return;

	for (rta = (struct rtattr *)(rtmmsg + 1); RTA_OK(rta, len);
			rta = RTA_NEXT(rta, len)) {
		switch(rta->rta_type) {
		case IFLA_IFNAME:
			ifname = RTA_DATA(rta);
			ifname_len = rta->rta_len;
			break;

		case IFLA_LINKINFO:
			nlmon = rta_linkinfo_kind(RTA_DATA(rta), rta->rta_len,
							NLMON_TYPE);
			break;

		default:
			break;
		}
	}

	if (!ifname)
		return;

	if (!nlmon)
		return;

	if ((rtmmsg->ifi_flags & (IFF_UP | IFF_ALLMULTI | IFF_NOARP)) !=
			(IFF_UP | IFF_ALLMULTI | IFF_NOARP))
		return;

	l_free(monitor_interface->ifname);
	monitor_interface->ifname = l_strndup(ifname, ifname_len);
	monitor_interface->exists = true;
}

static void iwmon_interface_lookup(struct iwmon_interface *monitor_interface)
{
	monitor_interface->rtnl =
		rtm_interface_send_message(monitor_interface->rtnl, NULL,
						RTM_GETLINK,
						iwmon_interface_lookup_callback,
						monitor_interface,
						iwmon_interface_lookup_done);
}

static int analyze_pcap(const char *pathname)
{
	struct l_queue *genl_list;
	const struct l_queue_entry *genl_entry;
	struct pcap *pcap;
	struct timeval tv;
	void *buf;
	uint32_t snaplen, len, real_len;
	int exit_status;
	unsigned long pkt_count = 0;
	unsigned long pkt_short = 0;
	unsigned long pkt_trunc = 0;
	unsigned long pkt_ether = 0;
	unsigned long pkt_pae = 0;
	unsigned long pkt_netlink = 0;
	unsigned long pkt_rtnl = 0;
	unsigned long pkt_genl = 0;
	unsigned long msg_netlink = 0;
	unsigned long msg_rtnl = 0;
	unsigned long msg_genl = 0;
	bool first;

	pcap = pcap_open(pathname);
	if (!pcap)
		return EXIT_FAILURE;

	if (pcap_get_type(pcap) != PCAP_TYPE_LINUX_SLL) {
		fprintf(stderr, "Invalid packet format\n");
		exit_status = EXIT_FAILURE;
		goto done;
	}

	snaplen = pcap_get_snaplen(pcap);
	if (snaplen > MAX_SNAPLEN)
		snaplen = MAX_SNAPLEN;

	buf = malloc(snaplen);
	if (!buf) {
		fprintf(stderr, "Failed to allocate packet buffer\n");
		exit_status = EXIT_FAILURE;
		goto done;
	}

	genl_list = l_queue_new();

	while (pcap_read(pcap, &tv, buf, snaplen, &len, &real_len)) {
		struct nlmsghdr *nlmsg;
		uint32_t aligned_len;
		uint16_t arphrd_type;
		uint16_t proto_type;

		pkt_count++;

		if (len < 16) {
			pkt_short++;
			continue;
		}

		arphrd_type = l_get_be16(buf + 2);
		proto_type = l_get_be16(buf + 14);

		switch (arphrd_type) {
		case ARPHRD_ETHER:
			pkt_ether++;
			switch (proto_type) {
			case ETH_P_PAE:
				pkt_pae++;
				break;
			}
			break;
		case ARPHRD_NETLINK:
			pkt_netlink++;
			switch (proto_type) {
			case NETLINK_ROUTE:
				pkt_rtnl++;
				break;
			case NETLINK_GENERIC:
				pkt_genl++;
				break;
			}
			break;
		}

		if (len < real_len) {
			pkt_trunc++;
			continue;
		}

		if (arphrd_type != ARPHRD_NETLINK)
			continue;

		aligned_len = NLMSG_ALIGN(len - 16);

		for (nlmsg = buf + 16; NLMSG_OK(nlmsg, aligned_len);
				nlmsg = NLMSG_NEXT(nlmsg, aligned_len)) {
			uint16_t type = nlmsg->nlmsg_type;

			msg_netlink++;
			switch (proto_type) {
			case NETLINK_ROUTE:
				msg_rtnl++;
				break;
			case NETLINK_GENERIC:
				if (type >= NLMSG_MIN_TYPE) {
					l_queue_remove(genl_list,
							L_UINT_TO_PTR(type));
					l_queue_push_tail(genl_list,
							L_UINT_TO_PTR(type));
				}
				msg_genl++;
				break;
			}
		}
	}

	printf("\n");
	printf("     Analyzed file: %s\n", pathname);
	printf("\n");
	printf(" Number of packets: %lu\n", pkt_count);
	printf("     Short packets: %lu\n", pkt_short);
	printf("  Tuncated packets: %lu\n", pkt_trunc);
	printf("\n");
	printf("  Ethernet packets: %lu\n", pkt_ether);
	printf("       PAE packets: %lu\n", pkt_pae);
	printf("\n");
	printf("   Netlink packets: %lu\n", pkt_netlink);
	printf("      RTNL packets: %lu\n", pkt_rtnl);
	printf("      GENL packets: %lu\n", pkt_genl);
	printf("\n");
	printf("  Netlink messages: %lu\n", msg_netlink);
	printf("     RTNL messages: %lu\n", msg_rtnl);
	printf("     GENL messages: %lu\n", msg_genl);
	printf("\n");
	for (genl_entry = l_queue_get_entries(genl_list), first = true;
				genl_entry;
				genl_entry = genl_entry->next, first = false) {
		uint16_t family = L_PTR_TO_UINT(genl_entry->data);
		const char *label, *desc;

		if (first)
			label = "     GENL families:";
		else
			label = "                   ";

		if (family == GENL_ID_CTRL)
			desc = "nlctrl";
		else
			desc = "";

		printf("%s 0x%02x (%u) %s\n", label, family, family, desc);
	}
	printf("\n");

	l_queue_destroy(genl_list, NULL);

	free(buf);

	exit_status = EXIT_SUCCESS;

done:
	pcap_close(pcap);

	return exit_status;
}

static int process_pcap(struct pcap *pcap, uint16_t id)
{
	struct nlmon *nlmon = NULL;
	struct timeval tv;
	uint8_t *buf;
	uint32_t snaplen, len, real_len;

	snaplen = pcap_get_snaplen(pcap);
	if (snaplen > MAX_SNAPLEN)
		snaplen = MAX_SNAPLEN;

	buf = malloc(snaplen);
	if (!buf) {
		fprintf(stderr, "Failed to allocate packet buffer\n");
		return EXIT_FAILURE;
	}

	nlmon = nlmon_create(id);

	while (pcap_read(pcap, &tv, buf, snaplen, &len, &real_len)) {
		uint16_t arphrd_type;
		uint16_t proto_type;
		uint16_t pkt_type;

		if (len < 16) {
			printf("Too short packet\n");
			continue;
		}

		if (len < real_len) {
			printf("Packet truncated from %u\n", real_len);
			continue;
		}

		pkt_type = l_get_be16(buf);
		arphrd_type = l_get_be16(buf + 2);
		proto_type = l_get_be16(buf + 14);

		switch (arphrd_type) {
		case ARPHRD_ETHER:
			switch (proto_type) {
			case ETH_P_PAE:
				nlmon_print_pae(nlmon, &tv, pkt_type, -1,
							buf + 16, len - 16);
				break;
			}
			break;
		case ARPHRD_NETLINK:
			switch (proto_type) {
			case NETLINK_ROUTE:
				nlmon_print_rtnl(nlmon, &tv,
							buf + 16, len - 16);
				break;
			case NETLINK_GENERIC:
				nlmon_print_genl(nlmon, &tv,
							buf + 16, len - 16);
				break;
			}
			break;
		default:
			printf("Unsupported ARPHRD %u\n", arphrd_type);
			break;
		}
	}

	nlmon_destroy(nlmon);

	free(buf);

	return EXIT_SUCCESS;
}

static void main_loop_quit(struct l_timeout *timeout, void *user_data)
{
	l_main_quit();
}

static void signal_handler(uint32_t signo, void *user_data)
{
	switch (signo) {
	case SIGINT:
	case SIGTERM:
		iwmon_interface_disable(&monitor_interface);

		timeout = l_timeout_create(1, main_loop_quit, NULL, NULL);
		break;
	}
}

static void usage(void)
{
	printf("iwmon - Wireless monitor\n"
		"Usage:\n");
	printf("\tiwmon [options]\n");
	printf("Options:\n"
		"\t-r, --read <file>      Read netlink PCAP trace file\n"
		"\t-w, --write <file>     Write netlink PCAP trace file\n"
		"\t-a, --analyze <file>   Analyze netlink PCAP trace file\n"
		"\t-i, --interface <dev>  Use specified netlink monitor\n"
		"\t-n, --nortnl           Don't show RTNL output\n"
		"\t-y, --nowiphy          Don't show 'New Wiphy' output\n"
		"\t-s, --noscan           Don't show scan result output\n"
		"\t-e, --noies            Don't show IEs except SSID\n"
		"\t-h, --help             Show help options\n");
}

static const struct option main_options[] = {
	{ "read",      required_argument, NULL, 'r' },
	{ "write",     required_argument, NULL, 'w' },
	{ "analyze",   required_argument, NULL, 'a' },
	{ "nl80211",   required_argument, NULL, 'F' },
	{ "interface", required_argument, NULL, 'i' },
	{ "nortnl",    no_argument,       NULL, 'n' },
	{ "nowiphy",   no_argument,       NULL, 'y' },
	{ "noscan",    no_argument,       NULL, 's' },
	{ "noies",     no_argument,       NULL, 'e' },
	{ "version",   no_argument,       NULL, 'v' },
	{ "help",      no_argument,       NULL, 'h' },
	{ }
};

int main(int argc, char *argv[])
{
	const char *reader_path = NULL;
	const char *analyze_path = NULL;
	const char *ifname = NULL;
	uint16_t nl80211_family = 0;
	int exit_status;

	for (;;) {
		int opt;

		opt = getopt_long(argc, argv, "r:w:a:F:i:nvhys",
						main_options, NULL);
		if (opt < 0)
			break;

		switch (opt) {
		case 'r':
			reader_path = optarg;
			break;
		case 'w':
			writer_path = optarg;
			break;
		case 'a':
			analyze_path = optarg;
			break;
		case 'F':
			if (strlen(optarg) > 3) {
				if (!strncasecmp(optarg, "0x", 2) &&
							!isxdigit(optarg[2])) {
					usage();
					return EXIT_FAILURE;
				}
				nl80211_family = strtoul(optarg + 2, NULL, 16);
			} else {
				if (!isdigit(optarg[0])) {
					usage();
					return EXIT_FAILURE;
				}
				nl80211_family = strtoul(optarg, NULL, 10);
			}
			if (nl80211_family == 0) {
				usage();
				return EXIT_FAILURE;
			}
			break;
		case 'i':
			ifname = optarg;
			break;
		case 'n':
			config.nortnl = true;
			break;
		case 'y':
			config.nowiphy = true;
			break;
		case 's':
			config.noscan = true;
			break;
		case 'e':
			config.noies = true;
			break;
		case 'v':
			printf("%s\n", VERSION);
			return EXIT_SUCCESS;
		case 'h':
			usage();
			return EXIT_SUCCESS;
		default:
			return EXIT_FAILURE;
		}
	}

	if (argc - optind > 0) {
		fprintf(stderr, "Invalid command line parameters\n");
		return EXIT_FAILURE;
	}

	if (reader_path && analyze_path) {
		fprintf(stderr, "Display and analyze can't be combined\n");
		return EXIT_FAILURE;
	}

	if (!l_main_init())
		return EXIT_FAILURE;

	printf("Wireless monitor ver %s\n", VERSION);

	if (analyze_path) {
		exit_status = analyze_pcap(analyze_path);
		goto done;
	}

	if (reader_path) {
		struct pcap *pcap;

		open_pager();

		pcap = pcap_open(reader_path);
		if (!pcap) {
			exit_status = EXIT_FAILURE;
			goto done;
		}

		if (pcap_get_type(pcap) != PCAP_TYPE_LINUX_SLL) {
			fprintf(stderr, "Invalid packet format\n");
			exit_status = EXIT_FAILURE;
		} else
			exit_status = process_pcap(pcap, nl80211_family);

		pcap_close(pcap);

		close_pager();
		goto done;
	}

	monitor_interface.ifname = l_strdup(ifname);
	iwmon_interface_lookup(&monitor_interface);

	exit_status = l_main_run_with_signal(signal_handler, NULL);

	l_netlink_destroy(monitor_interface.rtnl);
	l_netlink_destroy(monitor_interface.genl);
	l_free(monitor_interface.ifname);

	nlmon_close(nlmon);

done:
	l_timeout_remove(timeout);

	l_main_exit();

	return exit_status;
}