/* Library which manipulates firewall rules.  Version 0.1. */

/* Architecture of firewall rules is as follows:

 *

 * Chains go INPUT, FORWARD, OUTPUT then user chains.

 * Each user chain starts with an ERROR node.

 * Every chain ends with an unconditional jump: a RETURN for user chains,

 * and a POLICY for built-ins.

 */

/* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See

   COPYING for details). */

#include <assert.h>

#include <string.h>

#include <errno.h>

#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#ifdef DEBUG_CONNTRACK

#define inline

#endif

#if !defined(__GLIBC__) || (__GLIBC__ < 2)

typedef unsigned int socklen_t;

#endif

#include "libiptc/libiptc.h"

#define IP_VERSION	4

#define IP_OFFSET	0x1FFF

#define HOOK_PRE_ROUTING	NF_IP_PRE_ROUTING

#define HOOK_LOCAL_IN		NF_IP_LOCAL_IN

#define HOOK_FORWARD		NF_IP_FORWARD

#define HOOK_LOCAL_OUT		NF_IP_LOCAL_OUT

#define HOOK_POST_ROUTING	NF_IP_POST_ROUTING

#define STRUCT_ENTRY_TARGET	struct xt_entry_target

#define STRUCT_ENTRY		struct ipt_entry

#define STRUCT_ENTRY_MATCH	struct xt_entry_match

#define STRUCT_GETINFO		struct ipt_getinfo

#define STRUCT_GET_ENTRIES	struct ipt_get_entries

#define STRUCT_COUNTERS		struct xt_counters

#define STRUCT_COUNTERS_INFO	struct xt_counters_info

#define STRUCT_STANDARD_TARGET	struct xt_standard_target

#define STRUCT_REPLACE		struct ipt_replace

#define ENTRY_ITERATE		IPT_ENTRY_ITERATE

#define TABLE_MAXNAMELEN	XT_TABLE_MAXNAMELEN

#define FUNCTION_MAXNAMELEN	XT_FUNCTION_MAXNAMELEN

#define GET_TARGET		ipt_get_target

#define ERROR_TARGET		XT_ERROR_TARGET

#define NUMHOOKS		NF_IP_NUMHOOKS

#define IPT_CHAINLABEL		xt_chainlabel

#define TC_DUMP_ENTRIES		dump_entries

#define TC_IS_CHAIN		iptc_is_chain

#define TC_FIRST_CHAIN		iptc_first_chain

#define TC_NEXT_CHAIN		iptc_next_chain

#define TC_FIRST_RULE		iptc_first_rule

#define TC_NEXT_RULE		iptc_next_rule

#define TC_GET_TARGET		iptc_get_target

#define TC_BUILTIN		iptc_builtin

#define TC_GET_POLICY		iptc_get_policy

#define TC_INSERT_ENTRY		iptc_insert_entry

#define TC_REPLACE_ENTRY	iptc_replace_entry

#define TC_APPEND_ENTRY		iptc_append_entry

#define TC_CHECK_ENTRY		iptc_check_entry

#define TC_DELETE_ENTRY		iptc_delete_entry

#define TC_DELETE_NUM_ENTRY	iptc_delete_num_entry

#define TC_FLUSH_ENTRIES	iptc_flush_entries

#define TC_ZERO_ENTRIES		iptc_zero_entries

#define TC_READ_COUNTER		iptc_read_counter

#define TC_ZERO_COUNTER		iptc_zero_counter

#define TC_SET_COUNTER		iptc_set_counter

#define TC_CREATE_CHAIN		iptc_create_chain

#define TC_GET_REFERENCES	iptc_get_references

#define TC_DELETE_CHAIN		iptc_delete_chain

#define TC_RENAME_CHAIN		iptc_rename_chain

#define TC_SET_POLICY		iptc_set_policy

#define TC_GET_RAW_SOCKET	iptc_get_raw_socket

#define TC_INIT			iptc_init

#define TC_FREE			iptc_free

#define TC_COMMIT		iptc_commit

#define TC_STRERROR		iptc_strerror

#define TC_NUM_RULES		iptc_num_rules

#define TC_GET_RULE		iptc_get_rule

#define TC_OPS			iptc_ops

#define TC_AF			AF_INET

#define TC_IPPROTO		IPPROTO_IP

#define SO_SET_REPLACE		IPT_SO_SET_REPLACE

#define SO_SET_ADD_COUNTERS	IPT_SO_SET_ADD_COUNTERS

#define SO_GET_INFO		IPT_SO_GET_INFO

#define SO_GET_ENTRIES		IPT_SO_GET_ENTRIES

#define SO_GET_VERSION		IPT_SO_GET_VERSION

#define STANDARD_TARGET		XT_STANDARD_TARGET

#define LABEL_RETURN		IPTC_LABEL_RETURN

#define LABEL_ACCEPT		IPTC_LABEL_ACCEPT

#define LABEL_DROP		IPTC_LABEL_DROP

#define LABEL_QUEUE		IPTC_LABEL_QUEUE

#define ALIGN			XT_ALIGN

#define RETURN			XT_RETURN

#include "libiptc.c"

#define IP_PARTS_NATIVE(n)			\

(unsigned int)((n)>>24)&0xFF,			\

(unsigned int)((n)>>16)&0xFF,			\

(unsigned int)((n)>>8)&0xFF,			\

(unsigned int)((n)&0xFF)

#define IP_PARTS(n) IP_PARTS_NATIVE(ntohl(n))

static int

dump_entry(struct ipt_entry *e, struct xtc_handle *const handle)

{

	size_t i;

	STRUCT_ENTRY_TARGET *t;

	printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),

	       iptcb_entry2offset(handle, e));

	printf("SRC IP: %u.%u.%u.%u/%u.%u.%u.%u\n",

	       IP_PARTS(e->ip.src.s_addr),IP_PARTS(e->ip.smsk.s_addr));

	printf("DST IP: %u.%u.%u.%u/%u.%u.%u.%u\n",

	       IP_PARTS(e->ip.dst.s_addr),IP_PARTS(e->ip.dmsk.s_addr));

	printf("Interface: `%s'/", e->ip.iniface);

	for (i = 0; i < IFNAMSIZ; i++)

		printf("%c", e->ip.iniface_mask[i] ? 'X' : '.');

	printf("to `%s'/", e->ip.outiface);

	for (i = 0; i < IFNAMSIZ; i++)

		printf("%c", e->ip.outiface_mask[i] ? 'X' : '.');

	printf("\nProtocol: %u\n", e->ip.proto);

	printf("Flags: %02X\n", e->ip.flags);

	printf("Invflags: %02X\n", e->ip.invflags);

	printf("Counters: %llu packets, %llu bytes\n",

	       (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);

	printf("Cache: %08X\n", e->nfcache);

	IPT_MATCH_ITERATE(e, print_match);

	t = GET_TARGET(e);

	printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);

	if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {

		const unsigned char *data = t->data;

		int pos = *(const int *)data;

		if (pos < 0)

			printf("verdict=%s\n",

			       pos == -NF_ACCEPT-1 ? "NF_ACCEPT"

			       : pos == -NF_DROP-1 ? "NF_DROP"

			       : pos == -NF_QUEUE-1 ? "NF_QUEUE"

			       : pos == RETURN ? "RETURN"

			       : "UNKNOWN");

		else

			printf("verdict=%u\n", pos);

	} else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0)

		printf("error=`%s'\n", t->data);

	printf("\n");

	return 0;

}

static unsigned char *

is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask)

{

	unsigned int i;

	unsigned char *mptr;

	/* Always compare head structures: ignore mask here. */

	if (a->ip.src.s_addr != b->ip.src.s_addr

	    || a->ip.dst.s_addr != b->ip.dst.s_addr

	    || a->ip.smsk.s_addr != b->ip.smsk.s_addr

	    || a->ip.dmsk.s_addr != b->ip.dmsk.s_addr

	    || a->ip.proto != b->ip.proto

	    || a->ip.flags != b->ip.flags

	    || a->ip.invflags != b->ip.invflags)

		return NULL;

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

		if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i])

			return NULL;

		if ((a->ip.iniface[i] & a->ip.iniface_mask[i])

		    != (b->ip.iniface[i] & b->ip.iniface_mask[i]))

			return NULL;

		if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i])

			return NULL;

		if ((a->ip.outiface[i] & a->ip.outiface_mask[i])

		    != (b->ip.outiface[i] & b->ip.outiface_mask[i]))

			return NULL;

	}

	if (a->target_offset != b->target_offset

	    || a->next_offset != b->next_offset)

		return NULL;

	mptr = matchmask + sizeof(STRUCT_ENTRY);

	if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))

		return NULL;

	mptr += XT_ALIGN(sizeof(struct xt_entry_target));

	return mptr;

}

#if 0

/***************************** DEBUGGING ********************************/

static inline int

unconditional(const struct ipt_ip *ip)

{

	unsigned int i;

	for (i = 0; i < sizeof(*ip)/sizeof(uint32_t); i++)

		if (((uint32_t *)ip)[i])

			return 0;

	return 1;

}

static inline int

check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off)

{

	assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH));

	assert(ALIGN(m->u.match_size) == m->u.match_size);

	(*off) += m->u.match_size;

	return 0;

}

static inline int

check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,

	    unsigned int user_offset, int *was_return,

	    struct xtc_handle *h)

{

	unsigned int toff;

	STRUCT_STANDARD_TARGET *t;

	assert(e->target_offset >= sizeof(STRUCT_ENTRY));

	assert(e->next_offset >= e->target_offset

	       + sizeof(STRUCT_ENTRY_TARGET));

	toff = sizeof(STRUCT_ENTRY);

	IPT_MATCH_ITERATE(e, check_match, &toff);

	assert(toff == e->target_offset);

	t = (STRUCT_STANDARD_TARGET *)

		GET_TARGET((STRUCT_ENTRY *)e);

	/* next_offset will have to be multiple of entry alignment. */

	assert(e->next_offset == ALIGN(e->next_offset));

	assert(e->target_offset == ALIGN(e->target_offset));

	assert(t->target.u.target_size == ALIGN(t->target.u.target_size));

	assert(!TC_IS_CHAIN(t->target.u.user.name, h));

	if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) {

		assert(t->target.u.target_size

		       == ALIGN(sizeof(STRUCT_STANDARD_TARGET)));

		assert(t->verdict == -NF_DROP-1

		       || t->verdict == -NF_ACCEPT-1

		       || t->verdict == RETURN

		       || t->verdict < (int)h->entries->size);

		if (t->verdict >= 0) {

			STRUCT_ENTRY *te = get_entry(h, t->verdict);

			int idx;

			idx = iptcb_entry2index(h, te);

			assert(strcmp(GET_TARGET(te)->u.user.name,

				      XT_ERROR_TARGET)

			       != 0);

			assert(te != e);

			/* Prior node must be error node, or this node. */

			assert(t->verdict == iptcb_entry2offset(h, e)+e->next_offset

			       || strcmp(GET_TARGET(index2entry(h, idx-1))

					 ->u.user.name, XT_ERROR_TARGET)

			       == 0);

		}

		if (t->verdict == RETURN

		    && unconditional(&e->ip)

		    && e->target_offset == sizeof(*e))

			*was_return = 1;

		else

			*was_return = 0;

	} else if (strcmp(t->target.u.user.name, XT_ERROR_TARGET) == 0) {

		assert(t->target.u.target_size

		       == ALIGN(sizeof(struct ipt_error_target)));

		/* If this is in user area, previous must have been return */

		if (*off > user_offset)

			assert(*was_return);

		*was_return = 0;

	}

	else *was_return = 0;

	if (*off == user_offset)

		assert(strcmp(t->target.u.user.name, XT_ERROR_TARGET) == 0);

	(*off) += e->next_offset;

	(*i)++;

	return 0;

}

#ifdef IPTC_DEBUG

/* Do every conceivable sanity check on the handle */

static void

do_check(struct xtc_handle *h, unsigned int line)

{

	unsigned int i, n;

	unsigned int user_offset; /* Offset of first user chain */

	int was_return;

	assert(h->changed == 0 || h->changed == 1);

	if (strcmp(h->info.name, "filter") == 0) {

		assert(h->info.valid_hooks

		       == (1 << NF_IP_LOCAL_IN

			   | 1 << NF_IP_FORWARD

			   | 1 << NF_IP_LOCAL_OUT));

		/* Hooks should be first three */

		assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0);

		n = get_chain_end(h, 0);

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_FORWARD] == n);

		n = get_chain_end(h, n);

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);

		user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];

	} else if (strcmp(h->info.name, "nat") == 0) {

		assert((h->info.valid_hooks

		        == (1 << NF_IP_PRE_ROUTING

			    | 1 << NF_IP_POST_ROUTING

			    | 1 << NF_IP_LOCAL_OUT)) ||

		       (h->info.valid_hooks

			== (1 << NF_IP_PRE_ROUTING

			    | 1 << NF_IP_LOCAL_IN

			    | 1 << NF_IP_POST_ROUTING

			    | 1 << NF_IP_LOCAL_OUT)));

		assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);

		n = get_chain_end(h, 0);

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);

		n = get_chain_end(h, n);

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);

		user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];

		if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {

			n = get_chain_end(h, n);

			n += get_entry(h, n)->next_offset;

			assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);

			user_offset = h->info.hook_entry[NF_IP_LOCAL_IN];

		}

	} else if (strcmp(h->info.name, "mangle") == 0) {

		/* This code is getting ugly because linux < 2.4.18-pre6 had

		 * two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks

		 * */

		assert((h->info.valid_hooks

			== (1 << NF_IP_PRE_ROUTING

			    | 1 << NF_IP_LOCAL_OUT)) || 

		       (h->info.valid_hooks

			== (1 << NF_IP_PRE_ROUTING

			    | 1 << NF_IP_LOCAL_IN

			    | 1 << NF_IP_FORWARD

			    | 1 << NF_IP_LOCAL_OUT

			    | 1 << NF_IP_POST_ROUTING)));

		/* Hooks should be first five */

		assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);

		n = get_chain_end(h, 0);

		if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {

			n += get_entry(h, n)->next_offset;

			assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);

			n = get_chain_end(h, n);

		}

		if (h->info.valid_hooks & (1 << NF_IP_FORWARD)) {

			n += get_entry(h, n)->next_offset;

			assert(h->info.hook_entry[NF_IP_FORWARD] == n);

			n = get_chain_end(h, n);

		}

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);

		user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];

		if (h->info.valid_hooks & (1 << NF_IP_POST_ROUTING)) {

			n = get_chain_end(h, n);

			n += get_entry(h, n)->next_offset;

			assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);

			user_offset = h->info.hook_entry[NF_IP_POST_ROUTING];

		}

	} else if (strcmp(h->info.name, "raw") == 0) {

		assert(h->info.valid_hooks

		       == (1 << NF_IP_PRE_ROUTING

			   | 1 << NF_IP_LOCAL_OUT));

		/* Hooks should be first three */

		assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);

		n = get_chain_end(h, n);

		n += get_entry(h, n)->next_offset;

		assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);

		user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];

	} else {

		fprintf(stderr, "Unknown table `%s'\n", h->info.name);

		abort();

	}

	/* User chain == end of last builtin + policy entry */

	user_offset = get_chain_end(h, user_offset);

	user_offset += get_entry(h, user_offset)->next_offset;

	/* Overflows should be end of entry chains, and unconditional

           policy nodes. */

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

		STRUCT_ENTRY *e;

		STRUCT_STANDARD_TARGET *t;

		if (!(h->info.valid_hooks & (1 << i)))

			continue;

		assert(h->info.underflow[i]

		       == get_chain_end(h, h->info.hook_entry[i]));

		e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));

		assert(unconditional(&e->ip));

		assert(e->target_offset == sizeof(*e));

		t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);

		assert(t->target.u.target_size == ALIGN(sizeof(*t)));

		assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));

		assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);

		assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);

		/* Hooks and underflows must be valid entries */

		entry2index(h, get_entry(h, h->info.hook_entry[i]));

		entry2index(h, get_entry(h, h->info.underflow[i]));

	}

	assert(h->info.size

	       >= h->info.num_entries * (sizeof(STRUCT_ENTRY)

					 +sizeof(STRUCT_STANDARD_TARGET)));

	assert(h->entries.size

	       >= (h->new_number

		   * (sizeof(STRUCT_ENTRY)

		      + sizeof(STRUCT_STANDARD_TARGET))));

	assert(strcmp(h->info.name, h->entries.name) == 0);

	i = 0; n = 0;

	was_return = 0;

	/* Check all the entries. */

	ENTRY_ITERATE(h->entries.entrytable, h->entries.size,

		      check_entry, &i, &n, user_offset, &was_return, h);

	assert(i == h->new_number);

	assert(n == h->entries.size);

	/* Final entry must be error node */

	assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))

		      ->u.user.name,

		      ERROR_TARGET) == 0);

}

#endif /*IPTC_DEBUG*/

#endif