text: /* 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>
  #include <arpa/inet.h>
  
  #ifdef DEBUG_CONNTRACK
  #define inline
  #endif
  
  #if !defined(__GLIBC__) || (__GLIBC__ < 2)
  typedef unsigned int socklen_t;
  #endif
  
  #include "libiptc/libip6tc.h"
  
  #define HOOK_PRE_ROUTING	NF_IP6_PRE_ROUTING
  #define HOOK_LOCAL_IN		NF_IP6_LOCAL_IN
  #define HOOK_FORWARD		NF_IP6_FORWARD
  #define HOOK_LOCAL_OUT		NF_IP6_LOCAL_OUT
  #define HOOK_POST_ROUTING	NF_IP6_POST_ROUTING
  
  #define STRUCT_ENTRY_TARGET	struct xt_entry_target
  #define STRUCT_ENTRY		struct ip6t_entry
  #define STRUCT_ENTRY_MATCH	struct xt_entry_match
  #define STRUCT_GETINFO		struct ip6t_getinfo
  #define STRUCT_GET_ENTRIES	struct ip6t_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 ip6t_replace
  
  #define ENTRY_ITERATE		IP6T_ENTRY_ITERATE
  #define TABLE_MAXNAMELEN	XT_TABLE_MAXNAMELEN
  #define FUNCTION_MAXNAMELEN	XT_FUNCTION_MAXNAMELEN
  
  #define GET_TARGET		ip6t_get_target
  
  #define ERROR_TARGET		XT_ERROR_TARGET
  #define NUMHOOKS		NF_IP6_NUMHOOKS
  
  #define IPT_CHAINLABEL		xt_chainlabel
  
  #define TC_DUMP_ENTRIES		dump_entries6
  #define TC_IS_CHAIN		ip6tc_is_chain
  #define TC_FIRST_CHAIN		ip6tc_first_chain
  #define TC_NEXT_CHAIN		ip6tc_next_chain
  #define TC_FIRST_RULE		ip6tc_first_rule
  #define TC_NEXT_RULE		ip6tc_next_rule
  #define TC_GET_TARGET		ip6tc_get_target
  #define TC_BUILTIN		ip6tc_builtin
  #define TC_GET_POLICY		ip6tc_get_policy
  #define TC_INSERT_ENTRY		ip6tc_insert_entry
  #define TC_REPLACE_ENTRY	ip6tc_replace_entry
  #define TC_APPEND_ENTRY		ip6tc_append_entry
  #define TC_CHECK_ENTRY		ip6tc_check_entry
  #define TC_DELETE_ENTRY		ip6tc_delete_entry
  #define TC_DELETE_NUM_ENTRY	ip6tc_delete_num_entry
  #define TC_FLUSH_ENTRIES	ip6tc_flush_entries
  #define TC_ZERO_ENTRIES		ip6tc_zero_entries
  #define TC_ZERO_COUNTER		ip6tc_zero_counter
  #define TC_READ_COUNTER		ip6tc_read_counter
  #define TC_SET_COUNTER		ip6tc_set_counter
  #define TC_CREATE_CHAIN		ip6tc_create_chain
  #define TC_GET_REFERENCES	ip6tc_get_references
  #define TC_DELETE_CHAIN		ip6tc_delete_chain
  #define TC_RENAME_CHAIN		ip6tc_rename_chain
  #define TC_SET_POLICY		ip6tc_set_policy
  #define TC_GET_RAW_SOCKET	ip6tc_get_raw_socket
  #define TC_INIT			ip6tc_init
  #define TC_FREE			ip6tc_free
  #define TC_COMMIT		ip6tc_commit
  #define TC_STRERROR		ip6tc_strerror
  #define TC_NUM_RULES		ip6tc_num_rules
  #define TC_GET_RULE		ip6tc_get_rule
  #define TC_OPS			ip6tc_ops
  
  #define TC_AF			AF_INET6
  #define TC_IPPROTO		IPPROTO_IPV6
  
  #define SO_SET_REPLACE		IP6T_SO_SET_REPLACE
  #define SO_SET_ADD_COUNTERS	IP6T_SO_SET_ADD_COUNTERS
  #define SO_GET_INFO		IP6T_SO_GET_INFO
  #define SO_GET_ENTRIES		IP6T_SO_GET_ENTRIES
  #define SO_GET_VERSION		IP6T_SO_GET_VERSION
  
  #define STANDARD_TARGET		XT_STANDARD_TARGET
  #define LABEL_RETURN		IP6TC_LABEL_RETURN
  #define LABEL_ACCEPT		IP6TC_LABEL_ACCEPT
  #define LABEL_DROP		IP6TC_LABEL_DROP
  #define LABEL_QUEUE		IP6TC_LABEL_QUEUE
  
  #define ALIGN			XT_ALIGN
  #define RETURN			XT_RETURN
  
  #include "libiptc.c"
  
  #define BIT6(a, l) \
   ((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
  
  static int
  ipv6_prefix_length(const struct in6_addr *a)
  {
  	int l, i;
  	for (l = 0; l < 128; l++) {
  		if (BIT6(a, l) == 0)
  			break;
  	}
  	for (i = l + 1; i < 128; i++) {
  		if (BIT6(a, i) == 1)
  			return -1;
  	}
  	return l;
  }
  
  static int
  dump_entry(struct ip6t_entry *e, struct xtc_handle *const handle)
  {
  	size_t i;
  	char buf[40];
  	int len;
  	struct xt_entry_target *t;
  	
  	printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
  	       iptcb_entry2offset(handle, e));
  	puts("SRC IP: ");
  	inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf);
  	puts(buf);
  	putchar('/');
  	len = ipv6_prefix_length(&e->ipv6.smsk);
  	if (len != -1)
  		printf("%d", len);
  	else {
  		inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf);
  		puts(buf);
  	}
  	putchar('\n');
  	
  	puts("DST IP: ");
  	inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf);
  	puts(buf);
  	putchar('/');
  	len = ipv6_prefix_length(&e->ipv6.dmsk);
  	if (len != -1)
  		printf("%d", len);
  	else {
  		inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf);
  		puts(buf);
  	}
  	putchar('\n');
  	
  	printf("Interface: `%s'/", e->ipv6.iniface);
  	for (i = 0; i < IFNAMSIZ; i++)
  		printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.');
  	printf("to `%s'/", e->ipv6.outiface);
  	for (i = 0; i < IFNAMSIZ; i++)
  		printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.');
  	printf("\nProtocol: %u\n", e->ipv6.proto);
  	if (e->ipv6.flags & IP6T_F_TOS)
  		printf("TOS: %u\n", e->ipv6.tos);
  	printf("Flags: %02X\n", e->ipv6.flags);
  	printf("Invflags: %02X\n", e->ipv6.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);
  	
  	IP6T_MATCH_ITERATE(e, print_match);
  
  	t = ip6t_get_target(e);
  	printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
  	if (strcmp(t->u.user.name, XT_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 == XT_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 (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr))
  	    || memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr))
  	    || memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr))
  	    || memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr))
  	    || a->ipv6.proto != b->ipv6.proto
  	    || a->ipv6.tos != b->ipv6.tos
  	    || a->ipv6.flags != b->ipv6.flags
  	    || a->ipv6.invflags != b->ipv6.invflags)
  		return NULL;
  
  	for (i = 0; i < IFNAMSIZ; i++) {
  		if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i])
  			return NULL;
  		if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i])
  		    != (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i]))
  			return NULL;
  		if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i])
  			return NULL;
  		if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i])
  		    != (b->ipv6.outiface[i] & b->ipv6.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 (IP6T_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
  		return NULL;
  	mptr += XT_ALIGN(sizeof(struct xt_entry_target));
  
  	return mptr;
  }
  
  #if 0
  /* All zeroes == unconditional rule. */
  static inline int
  unconditional(const struct ip6t_ip6 *ipv6)
  {
  	unsigned int i;
  
  	for (i = 0; i < sizeof(*ipv6); i++)
  		if (((char *)ipv6)[i])
  			break;
  
  	return (i == sizeof(*ipv6));
  }
  #endif
  