/*

 * m_ipt.c	iptables based targets

 *		utilities mostly ripped from iptables <duh, its the linux way>

 *

 *		This program is free software; you can distribute it and/or

 *		modify it under the terms of the GNU General Public License

 *		as published by the Free Software Foundation; either version

 *		2 of the License, or (at your option) any later version.

 *

 * Authors:  J Hadi Salim (hadi@cyberus.ca)

 */

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <iptables.h>

#include <linux/netfilter.h>

#include <linux/netfilter_ipv4/ip_tables.h>

#include "utils.h"

#include "tc_util.h"

#include <linux/tc_act/tc_ipt.h>

#include <stdio.h>

#include <dlfcn.h>

#include <getopt.h>

#include <errno.h>

#include <string.h>

#include <netdb.h>

#include <stdlib.h>

#include <ctype.h>

#include <stdarg.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/wait.h>

static const char *pname = "tc-ipt";

static const char *tname = "mangle";

static const char *pversion = "0.1";

static const char *ipthooks[] = {

	"NF_IP_PRE_ROUTING",

	"NF_IP_LOCAL_IN",

	"NF_IP_FORWARD",

	"NF_IP_LOCAL_OUT",

	"NF_IP_POST_ROUTING",

};

static struct option original_opts[] = {

	{"jump", 1, 0, 'j'},

	{0, 0, 0, 0}

};

static struct xtables_target *t_list;

static struct option *opts = original_opts;

static unsigned int global_option_offset;

#define OPTION_OFFSET 256

char *lib_dir;

void

xtables_register_target(struct xtables_target *me)

{

	me->next = t_list;

	t_list = me;

}

static void exit_tryhelp(int status)

{

	fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",

		pname, pname);

	exit(status);

}

static void exit_error(enum xtables_exittype status, char *msg, ...)

{

	va_list args;

	va_start(args, msg);

	fprintf(stderr, "%s v%s: ", pname, pversion);

	vfprintf(stderr, msg, args);

	va_end(args);

	fprintf(stderr, "\n");

	if (status == PARAMETER_PROBLEM)

		exit_tryhelp(status);

	if (status == VERSION_PROBLEM)

		fprintf(stderr,

			"Perhaps iptables or your kernel needs to be upgraded.\n");

	exit(status);

}

/* stolen from iptables 1.2.11

They should really have them as a library so i can link to them

Email them next time i remember

*/

static void free_opts(struct option *local_opts)

{

	if (local_opts != original_opts) {

		free(local_opts);

		opts = original_opts;

		global_option_offset = 0;

	}

}

static struct option *

merge_options(struct option *oldopts, const struct option *newopts,

	      unsigned int *option_offset)

{

	struct option *merge;

	unsigned int num_old, num_new, i;

	for (num_old = 0; oldopts[num_old].name; num_old++);

	for (num_new = 0; newopts[num_new].name; num_new++);

	*option_offset = global_option_offset + OPTION_OFFSET;

	merge = malloc(sizeof(struct option) * (num_new + num_old + 1));

	memcpy(merge, oldopts, num_old * sizeof(struct option));

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

		merge[num_old + i] = newopts[i];

		merge[num_old + i].val += *option_offset;

	}

	memset(merge + num_old + num_new, 0, sizeof(struct option));

	return merge;

}

static void *

fw_calloc(size_t count, size_t size)

{

	void *p;

	if ((p = (void *) calloc(count, size)) == NULL) {

		perror("iptables: calloc failed");

		exit(1);

	}

	return p;

}

static struct xtables_target *

find_t(char *name)

{

	struct xtables_target *m;

	for (m = t_list; m; m = m->next) {

		if (strcmp(m->name, name) == 0)

			return m;

	}

	return NULL;

}

static struct xtables_target *

get_target_name(const char *name)

{

	void *handle;

	char *error;

	char *new_name, *lname;

	struct xtables_target *m;

	char path[strlen(lib_dir) + sizeof("/libipt_.so") + strlen(name)];

#ifdef NO_SHARED_LIBS

	return NULL;

#endif

	new_name = calloc(1, strlen(name) + 1);

	lname = calloc(1, strlen(name) + 1);

	if (!new_name)

		exit_error(PARAMETER_PROBLEM, "get_target_name");

	if (!lname)

		exit_error(PARAMETER_PROBLEM, "get_target_name");

	strcpy(new_name, name);

	strcpy(lname, name);

	if (isupper(lname[0])) {

		int i;

		for (i = 0; i < strlen(name); i++) {

			lname[i] = tolower(lname[i]);

		}

	}

	if (islower(new_name[0])) {

		int i;

		for (i = 0; i < strlen(new_name); i++) {

			new_name[i] = toupper(new_name[i]);

		}

	}

	/* try libxt_xx first */

	sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);

	handle = dlopen(path, RTLD_LAZY);

	if (!handle) {

		/* try libipt_xx next */

		sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);

		handle = dlopen(path, RTLD_LAZY);

		if (!handle) {

			sprintf(path, "%s/libxt_%s.so", lib_dir, lname);

			handle = dlopen(path, RTLD_LAZY);

		}

		if (!handle) {

			sprintf(path, "%s/libipt_%s.so", lib_dir, lname);

			handle = dlopen(path, RTLD_LAZY);

		}

		/* ok, lets give up .. */

		if (!handle) {

			fputs(dlerror(), stderr);

			printf("\n");

			free(new_name);

			free(lname);

			return NULL;

		}

	}

	m = dlsym(handle, new_name);

	if ((error = dlerror()) != NULL) {

		m = (struct xtables_target *) dlsym(handle, lname);

		if ((error = dlerror()) != NULL) {

			m = find_t(new_name);

			if (m == NULL) {

				m = find_t(lname);

				if (m == NULL) {

					fputs(error, stderr);

					fprintf(stderr, "\n");

					dlclose(handle);

					free(new_name);

					free(lname);

					return NULL;

				}

			}

		}

	}

	free(new_name);

	free(lname);

	return m;

}

static void set_revision(char *name, u_int8_t revision)

{

	/* Old kernel sources don't have ".revision" field,

	*  but we stole a byte from name. */

	name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';

	name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;

}

/*

 * we may need to check for version mismatch

*/

static int build_st(struct xtables_target *target, struct ipt_entry_target *t)

{

	if (target) {

		size_t size;

		size =

		    XT_ALIGN(sizeof(struct ipt_entry_target)) + target->size;

		if (t == NULL) {

			target->t = fw_calloc(1, size);

			target->t->u.target_size = size;

			if (target->init != NULL)

				target->init(target->t);

			set_revision(target->t->u.user.name, target->revision);

		} else {

			target->t = t;

		}

		strcpy(target->t->u.user.name, target->name);

		return 0;

	}

	return -1;

}

static int parse_ipt(struct action_util *a, int *argc_p,

		     char ***argv_p, int tca_id, struct nlmsghdr *n)

{

	struct xtables_target *m = NULL;

	struct ipt_entry fw;

	struct rtattr *tail;

	int c;

	int rargc = *argc_p;

	char **argv = *argv_p;

	int argc = 0, iargc = 0;

	char k[FILTER_NAMESZ];

	int size = 0;

	int iok = 0, ok = 0;

	__u32 hook = 0, index = 0;

	lib_dir = getenv("IPTABLES_LIB_DIR");

	if (!lib_dir)

		lib_dir = IPT_LIB_DIR;

	{

		int i;

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

			if (!argv[i] || strcmp(argv[i], "action") == 0)

				break;

		}

		iargc = argc = i;

	}

	if (argc <= 2) {

		fprintf(stderr, "bad arguments to ipt %d vs %d\n", argc, rargc);

		return -1;

	}

	while (1) {

		c = getopt_long(argc, argv, "j:", opts, NULL);

		if (c == -1)

			break;

		switch (c) {

		case 'j':

			m = get_target_name(optarg);

			if (m != NULL) {

				if (build_st(m, NULL) < 0) {

					printf(" %s error\n", m->name);

					return -1;

				}

				opts =

				    merge_options(opts, m->extra_opts,

						  &m->option_offset);

			} else {

				fprintf(stderr, " failed to find target %s\n\n", optarg);

				return -1;

			}

			ok++;

			break;

		default:

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

			if (m) {

				m->parse(c - m->option_offset, argv, 0,

					 &m->tflags, NULL, &m->t);

			} else {

				fprintf(stderr, " failed to find target %s\n\n", optarg);

				return -1;

			}

			ok++;

			break;

		}

	}

	if (iargc > optind) {

		if (matches(argv[optind], "index") == 0) {

			if (get_u32(&index, argv[optind + 1], 10)) {

				fprintf(stderr, "Illegal \"index\"\n");

				free_opts(opts);

				return -1;

			}

			iok++;

			optind += 2;

		}

	}

	if (!ok && !iok) {

		fprintf(stderr, " ipt Parser BAD!! (%s)\n", *argv);

		return -1;

	}

	/* check that we passed the correct parameters to the target */

	if (m)

		m->final_check(m->tflags);

	{

		struct tcmsg *t = NLMSG_DATA(n);

		if (t->tcm_parent != TC_H_ROOT

		    && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {

			hook = NF_IP_PRE_ROUTING;

		} else {

			hook = NF_IP_POST_ROUTING;

		}

	}

	tail = addattr_nest(n, MAX_MSG, tca_id);

	fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);

	fprintf(stdout, "\ttarget: ");

	if (m)

		m->print(NULL, m->t, 0);

	fprintf(stdout, " index %d\n", index);

	if (strlen(tname) > 16) {

		size = 16;

		k[15] = 0;

	} else {

		size = 1 + strlen(tname);

	}

	strncpy(k, tname, size);

	addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);

	addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);

	addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);

	if (m)

		addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);

	addattr_nest_end(n, tail);

	argc -= optind;

	argv += optind;

	*argc_p = rargc - iargc;

	*argv_p = argv;

	optind = 0;

	free_opts(opts);

	/* Clear flags if target will be used again */

        m->tflags = 0;

        m->used = 0;

	/* Free allocated memory */

	if (m->t)

	    free(m->t);

	return 0;

}

static int

print_ipt(struct action_util *au, FILE * f, struct rtattr *arg)

{

	struct rtattr *tb[TCA_IPT_MAX + 1];

	struct ipt_entry_target *t = NULL;

	struct xtables_target *m;

	__u32 hook;

	if (arg == NULL)

		return -1;

	lib_dir = getenv("IPTABLES_LIB_DIR");

	if (!lib_dir)

		lib_dir = IPT_LIB_DIR;

	parse_rtattr_nested(tb, TCA_IPT_MAX, arg);

	if (tb[TCA_IPT_TABLE] == NULL) {

		fprintf(stderr,  "Missing ipt table name, assuming mangle\n");

	} else {

		fprintf(f, "tablename: %s ",

			rta_getattr_str(tb[TCA_IPT_TABLE]));

	}

	if (tb[TCA_IPT_HOOK] == NULL) {

		fprintf(stderr, "Missing ipt hook name\n ");

		return -1;

	}

	hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);

	fprintf(f, " hook: %s\n", ipthooks[hook]);

	if (tb[TCA_IPT_TARG] == NULL) {

		fprintf(stderr, "Missing ipt target parameters\n");

		return -1;

	}

	t = RTA_DATA(tb[TCA_IPT_TARG]);

	m = get_target_name(t->u.user.name);

	if (m != NULL) {

		if (build_st(m, t) < 0) {

			fprintf(stderr, " %s error\n", m->name);

			return -1;

		}

		opts =

			merge_options(opts, m->extra_opts,

				      &m->option_offset);

	} else {

		fprintf(stderr, " failed to find target %s\n\n",

			t->u.user.name);

		return -1;

	}

	fprintf(f, "\ttarget ");

	m->print(NULL, m->t, 0);

	if (tb[TCA_IPT_INDEX] == NULL) {

		fprintf(stderr, "Missing ipt target index\n");

	} else {

		__u32 index;

		index = rta_getattr_u32(tb[TCA_IPT_INDEX]);

		fprintf(f, "\n\tindex %u", index);

	}

	if (tb[TCA_IPT_CNT]) {

		struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);

		fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);

	}

	if (show_stats) {

		if (tb[TCA_IPT_TM]) {

			struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);

			print_tm(f, tm);

		}

	}

	fprintf(f, "\n");

	free_opts(opts);

	return 0;

}

struct action_util ipt_action_util = {

	.id = "ipt",

	.parse_aopt = parse_ipt,

	.print_aopt = print_ipt,

};