/* 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#ifdef NF_IP_DROPPING#define HOOK_DROPPING		NF_IP_DROPPING#endif#define STRUCT_ENTRY_TARGET	struct ipt_entry_target#define STRUCT_ENTRY		struct ipt_entry#define STRUCT_ENTRY_MATCH	struct ipt_entry_match#define STRUCT_GETINFO		struct ipt_getinfo#define STRUCT_GET_ENTRIES	struct ipt_get_entries#define STRUCT_COUNTERS		struct ipt_counters#define STRUCT_COUNTERS_INFO	struct ipt_counters_info#define STRUCT_STANDARD_TARGET	struct ipt_standard_target#define STRUCT_REPLACE		struct ipt_replace#define STRUCT_TC_HANDLE	struct iptc_handle#define TC_HANDLE_T		iptc_handle_t#define ENTRY_ITERATE		IPT_ENTRY_ITERATE#define TABLE_MAXNAMELEN	IPT_TABLE_MAXNAMELEN#define FUNCTION_MAXNAMELEN	IPT_FUNCTION_MAXNAMELEN#define GET_TARGET		ipt_get_target#define ERROR_TARGET		IPT_ERROR_TARGET#define NUMHOOKS		NF_IP_NUMHOOKS#define IPT_CHAINLABEL		ipt_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_DELETE_ENTRY		iptc_delete_entry#define TC_DELETE_NUM_ENTRY	iptc_delete_num_entry#define TC_CHECK_PACKET		iptc_check_packet#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_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		IPT_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			IPT_ALIGN#define RETURN			IPT_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))intdump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T 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) {		int pos = *(int *)t->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, IPT_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 += IPT_ALIGN(sizeof(struct ipt_entry_target));	return mptr;}#if 0/***************************** DEBUGGING ********************************/static inline intunconditional(const struct ipt_ip *ip){	unsigned int i;	for (i = 0; i < sizeof(*ip)/sizeof(u_int32_t); i++)		if (((u_int32_t *)ip)[i])			return 0;	return 1;}static inline intcheck_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 intcheck_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,	    unsigned int user_offset, int *was_return,	    TC_HANDLE_T 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,				      IPT_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, IPT_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, IPT_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, IPT_ERROR_TARGET) == 0);	(*off) += e->next_offset;	(*i)++;	return 0;}#ifdef IPTC_DEBUG/* Do every conceivable sanity check on the handle */static voiddo_check(TC_HANDLE_T 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];#ifdef NF_IP_DROPPING	} else if (strcmp(h->info.name, "drop") == 0) {		assert(h->info.valid_hooks == (1 << NF_IP_DROPPING));		/* Hook should be first */		assert(h->info.hook_entry[NF_IP_DROPPING] == 0);		user_offset = 0;#endif	} 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