text: /* Shared library add-on to iptables for conntrack matching support.
   * GPL (C) 2001  Marc Boucher (marc@mbsi.ca).
   */
  
  #include <stdio.h>
  #include <netdb.h>
  #include <string.h>
  #include <stdlib.h>
  #include <getopt.h>
  #include <ctype.h>
  #include <iptables.h>
  #include <linux/netfilter_ipv4/ip_conntrack.h>
  #include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
  /* For 64bit kernel / 32bit userspace */
  #include "../include/linux/netfilter_ipv4/ipt_conntrack.h"
  
  #ifndef IPT_CONNTRACK_STATE_UNTRACKED
  #define IPT_CONNTRACK_STATE_UNTRACKED (1 << (IP_CT_NUMBER + 3))
  #endif
  
  /* Function which prints out usage message. */
  static void
  help(void)
  {
  	printf(
  "conntrack match v%s options:\n"
  " [!] --ctstate [INVALID|ESTABLISHED|NEW|RELATED|UNTRACKED|SNAT|DNAT][,...]\n"
  "				State(s) to match\n"
  " [!] --ctproto	proto		Protocol to match; by number or name, eg. `tcp'\n"
  "     --ctorigsrc  [!] address[/mask]\n"
  "				Original source specification\n"
  "     --ctorigdst  [!] address[/mask]\n"
  "				Original destination specification\n"
  "     --ctreplsrc  [!] address[/mask]\n"
  "				Reply source specification\n"
  "     --ctrepldst  [!] address[/mask]\n"
  "				Reply destination specification\n"
  " [!] --ctstatus [NONE|EXPECTED|SEEN_REPLY|ASSURED|CONFIRMED][,...]\n"
  "				Status(es) to match\n"
  " [!] --ctexpire time[:time]	Match remaining lifetime in seconds against\n"
  "				value or range of values (inclusive)\n"
  "\n", IPTABLES_VERSION);
  }
  
  
  
  static struct option opts[] = {
  	{ "ctstate", 1, 0, '1' },
  	{ "ctproto", 1, 0, '2' },
  	{ "ctorigsrc", 1, 0, '3' },
  	{ "ctorigdst", 1, 0, '4' },
  	{ "ctreplsrc", 1, 0, '5' },
  	{ "ctrepldst", 1, 0, '6' },
  	{ "ctstatus", 1, 0, '7' },
  	{ "ctexpire", 1, 0, '8' },
  	{0}
  };
  
  static int
  parse_state(const char *state, size_t strlen, struct ipt_conntrack_info *sinfo)
  {
  	if (strncasecmp(state, "INVALID", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_INVALID;
  	else if (strncasecmp(state, "NEW", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_NEW);
  	else if (strncasecmp(state, "ESTABLISHED", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED);
  	else if (strncasecmp(state, "RELATED", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_RELATED);
  	else if (strncasecmp(state, "UNTRACKED", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_UNTRACKED;
  	else if (strncasecmp(state, "SNAT", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_SNAT;
  	else if (strncasecmp(state, "DNAT", strlen) == 0)
  		sinfo->statemask |= IPT_CONNTRACK_STATE_DNAT;
  	else
  		return 0;
  	return 1;
  }
  
  static void
  parse_states(const char *arg, struct ipt_conntrack_info *sinfo)
  {
  	const char *comma;
  
  	while ((comma = strchr(arg, ',')) != NULL) {
  		if (comma == arg || !parse_state(arg, comma-arg, sinfo))
  			exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg);
  		arg = comma+1;
  	}
  
  	if (strlen(arg) == 0 || !parse_state(arg, strlen(arg), sinfo))
  		exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg);
  }
  
  static int
  parse_status(const char *status, size_t strlen, struct ipt_conntrack_info *sinfo)
  {
  	if (strncasecmp(status, "NONE", strlen) == 0)
  		sinfo->statusmask |= 0;
  	else if (strncasecmp(status, "EXPECTED", strlen) == 0)
  		sinfo->statusmask |= IPS_EXPECTED;
  	else if (strncasecmp(status, "SEEN_REPLY", strlen) == 0)
  		sinfo->statusmask |= IPS_SEEN_REPLY;
  	else if (strncasecmp(status, "ASSURED", strlen) == 0)
  		sinfo->statusmask |= IPS_ASSURED;
  #ifdef IPS_CONFIRMED
  	else if (strncasecmp(status, "CONFIRMED", strlen) == 0)
  		sinfo->stausmask |= IPS_CONFIRMED;
  #endif
  	else
  		return 0;
  	return 1;
  }
  
  static void
  parse_statuses(const char *arg, struct ipt_conntrack_info *sinfo)
  {
  	const char *comma;
  
  	while ((comma = strchr(arg, ',')) != NULL) {
  		if (comma == arg || !parse_status(arg, comma-arg, sinfo))
  			exit_error(PARAMETER_PROBLEM, "Bad ctstatus `%s'", arg);
  		arg = comma+1;
  	}
  
  	if (strlen(arg) == 0 || !parse_status(arg, strlen(arg), sinfo))
  		exit_error(PARAMETER_PROBLEM, "Bad ctstatus `%s'", arg);
  }
  
  #ifdef KERNEL_64_USERSPACE_32
  static unsigned long long
  parse_expire(const char *s)
  {
  	unsigned long long len;
  	
  	if (string_to_number_ll(s, 0, 0, &len) == -1)
  		exit_error(PARAMETER_PROBLEM, "expire value invalid: `%s'\n", s);
  	else
  		return len;
  }
  #else
  static unsigned long
  parse_expire(const char *s)
  {
  	unsigned int len;
  	
  	if (string_to_number(s, 0, 0, &len) == -1)
  		exit_error(PARAMETER_PROBLEM, "expire value invalid: `%s'\n", s);
  	else
  		return len;
  }
  #endif
  
  /* If a single value is provided, min and max are both set to the value */
  static void
  parse_expires(const char *s, struct ipt_conntrack_info *sinfo)
  {
  	char *buffer;
  	char *cp;
  
  	buffer = strdup(s);
  	if ((cp = strchr(buffer, ':')) == NULL)
  		sinfo->expires_min = sinfo->expires_max = parse_expire(buffer);
  	else {
  		*cp = '\0';
  		cp++;
  
  		sinfo->expires_min = buffer[0] ? parse_expire(buffer) : 0;
  		sinfo->expires_max = cp[0] ? parse_expire(cp) : -1;
  	}
  	free(buffer);
  	
  	if (sinfo->expires_min > sinfo->expires_max)
  		exit_error(PARAMETER_PROBLEM,
  #ifdef KERNEL_64_USERSPACE_32
  		           "expire min. range value `%llu' greater than max. "
  		           "range value `%llu'", sinfo->expires_min, sinfo->expires_max);
  #else
  		           "expire min. range value `%lu' greater than max. "
  		           "range value `%lu'", sinfo->expires_min, sinfo->expires_max);
  #endif
  }
  
  /* Function which parses command options; returns true if it
     ate an option */
  static int
  parse(int c, char **argv, int invert, unsigned int *flags,
        const struct ipt_entry *entry,
        unsigned int *nfcache,
        struct ipt_entry_match **match)
  {
  	struct ipt_conntrack_info *sinfo = (struct ipt_conntrack_info *)(*match)->data;
  	char *protocol = NULL;
  	unsigned int naddrs = 0;
  	struct in_addr *addrs = NULL;
  
  
  	switch (c) {
  	case '1':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		parse_states(argv[optind-1], sinfo);
  		if (invert) {
  			sinfo->invflags |= IPT_CONNTRACK_STATE;
  		}
  		sinfo->flags |= IPT_CONNTRACK_STATE;
  		break;
  
  	case '2':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		if(invert)
  			sinfo->invflags |= IPT_CONNTRACK_PROTO;
  
  		/* Canonicalize into lower case */
  		for (protocol = argv[optind-1]; *protocol; protocol++)
  			*protocol = tolower(*protocol);
  
  		protocol = argv[optind-1];
  		sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum = parse_protocol(protocol);
  
  		if (sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum == 0
  		    && (sinfo->invflags & IPT_INV_PROTO))
  			exit_error(PARAMETER_PROBLEM,
  				   "rule would never match protocol");
  
  		sinfo->flags |= IPT_CONNTRACK_PROTO;
  		break;
  
  	case '3':
  		check_inverse(optarg, &invert, &optind, 9);
  
  		if (invert)
  			sinfo->invflags |= IPT_CONNTRACK_ORIGSRC;
  
  		parse_hostnetworkmask(argv[optind-1], &addrs,
  					&sinfo->sipmsk[IP_CT_DIR_ORIGINAL],
  					&naddrs);
  		if(naddrs > 1)
  			exit_error(PARAMETER_PROBLEM,
  				"multiple IP addresses not allowed");
  
  		if(naddrs == 1) {
  			sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip = addrs[0].s_addr;
  		}
  
  		sinfo->flags |= IPT_CONNTRACK_ORIGSRC;
  		break;
  
  	case '4':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		if (invert)
  			sinfo->invflags |= IPT_CONNTRACK_ORIGDST;
  
  		parse_hostnetworkmask(argv[optind-1], &addrs,
  					&sinfo->dipmsk[IP_CT_DIR_ORIGINAL],
  					&naddrs);
  		if(naddrs > 1)
  			exit_error(PARAMETER_PROBLEM,
  				"multiple IP addresses not allowed");
  
  		if(naddrs == 1) {
  			sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip = addrs[0].s_addr;
  		}
  
  		sinfo->flags |= IPT_CONNTRACK_ORIGDST;
  		break;
  
  	case '5':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		if (invert)
  			sinfo->invflags |= IPT_CONNTRACK_REPLSRC;
  
  		parse_hostnetworkmask(argv[optind-1], &addrs,
  					&sinfo->sipmsk[IP_CT_DIR_REPLY],
  					&naddrs);
  		if(naddrs > 1)
  			exit_error(PARAMETER_PROBLEM,
  				"multiple IP addresses not allowed");
  
  		if(naddrs == 1) {
  			sinfo->tuple[IP_CT_DIR_REPLY].src.ip = addrs[0].s_addr;
  		}
  
  		sinfo->flags |= IPT_CONNTRACK_REPLSRC;
  		break;
  
  	case '6':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		if (invert)
  			sinfo->invflags |= IPT_CONNTRACK_REPLDST;
  
  		parse_hostnetworkmask(argv[optind-1], &addrs,
  					&sinfo->dipmsk[IP_CT_DIR_REPLY],
  					&naddrs);
  		if(naddrs > 1)
  			exit_error(PARAMETER_PROBLEM,
  				"multiple IP addresses not allowed");
  
  		if(naddrs == 1) {
  			sinfo->tuple[IP_CT_DIR_REPLY].dst.ip = addrs[0].s_addr;
  		}
  
  		sinfo->flags |= IPT_CONNTRACK_REPLDST;
  		break;
  
  	case '7':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		parse_statuses(argv[optind-1], sinfo);
  		if (invert) {
  			sinfo->invflags |= IPT_CONNTRACK_STATUS;
  		}
  		sinfo->flags |= IPT_CONNTRACK_STATUS;
  		break;
  
  	case '8':
  		check_inverse(optarg, &invert, &optind, 0);
  
  		parse_expires(argv[optind-1], sinfo);
  		if (invert) {
  			sinfo->invflags |= IPT_CONNTRACK_EXPIRES;
  		}
  		sinfo->flags |= IPT_CONNTRACK_EXPIRES;
  		break;
  
  	default:
  		return 0;
  	}
  
  	*flags = sinfo->flags;
  	return 1;
  }
  
  static void
  final_check(unsigned int flags)
  {
  	if (!flags)
  		exit_error(PARAMETER_PROBLEM, "You must specify one or more options");
  }
  
  static void
  print_state(unsigned int statemask)
  {
  	const char *sep = "";
  
  	if (statemask & IPT_CONNTRACK_STATE_INVALID) {
  		printf("%sINVALID", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_NEW)) {
  		printf("%sNEW", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_RELATED)) {
  		printf("%sRELATED", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED)) {
  		printf("%sESTABLISHED", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_UNTRACKED) {
  		printf("%sUNTRACKED", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_SNAT) {
  		printf("%sSNAT", sep);
  		sep = ",";
  	}
  	if (statemask & IPT_CONNTRACK_STATE_DNAT) {
  		printf("%sDNAT", sep);
  		sep = ",";
  	}
  	printf(" ");
  }
  
  static void
  print_status(unsigned int statusmask)
  {
  	const char *sep = "";
  
  	if (statusmask & IPS_EXPECTED) {
  		printf("%sEXPECTED", sep);
  		sep = ",";
  	}
  	if (statusmask & IPS_SEEN_REPLY) {
  		printf("%sSEEN_REPLY", sep);
  		sep = ",";
  	}
  	if (statusmask & IPS_ASSURED) {
  		printf("%sASSURED", sep);
  		sep = ",";
  	}
  #ifdef IPS_CONFIRMED
  	if (statusmask & IPS_CONFIRMED) {
  		printf("%sCONFIRMED", sep);
  		sep =",";
  	}
  #endif
  	if (statusmask == 0) {
  		printf("%sNONE", sep);
  		sep = ",";
  	}
  	printf(" ");
  }
  
  static void
  print_addr(struct in_addr *addr, struct in_addr *mask, int inv, int numeric)
  {
  	char buf[BUFSIZ];
  
          if (inv) 
                 	printf("! ");
  
  	if (mask->s_addr == 0L && !numeric)
  		printf("%s ", "anywhere");
  	else {
  		if (numeric)
  			sprintf(buf, "%s", addr_to_dotted(addr));
  		else
  			sprintf(buf, "%s", addr_to_anyname(addr));
  		strcat(buf, mask_to_dotted(mask));
  		printf("%s ", buf);
  	}
  }
  
  /* Saves the matchinfo in parsable form to stdout. */
  static void
  matchinfo_print(const struct ipt_ip *ip, const struct ipt_entry_match *match, int numeric, const char *optpfx)
  {
  	struct ipt_conntrack_info *sinfo = (struct ipt_conntrack_info *)match->data;
  
  	if(sinfo->flags & IPT_CONNTRACK_STATE) {
  		printf("%sctstate ", optpfx);
          	if (sinfo->invflags & IPT_CONNTRACK_STATE)
                  	printf("! ");
  		print_state(sinfo->statemask);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_PROTO) {
  		printf("%sctproto ", optpfx);
          	if (sinfo->invflags & IPT_CONNTRACK_PROTO)
                  	printf("! ");
  		printf("%u ", sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_ORIGSRC) {
  		printf("%sctorigsrc ", optpfx);
  
  		print_addr(
  		    (struct in_addr *)&sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
  		    &sinfo->sipmsk[IP_CT_DIR_ORIGINAL],
  		    sinfo->invflags & IPT_CONNTRACK_ORIGSRC,
  		    numeric);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_ORIGDST) {
  		printf("%sctorigdst ", optpfx);
  
  		print_addr(
  		    (struct in_addr *)&sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
  		    &sinfo->dipmsk[IP_CT_DIR_ORIGINAL],
  		    sinfo->invflags & IPT_CONNTRACK_ORIGDST,
  		    numeric);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_REPLSRC) {
  		printf("%sctreplsrc ", optpfx);
  
  		print_addr(
  		    (struct in_addr *)&sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
  		    &sinfo->sipmsk[IP_CT_DIR_REPLY],
  		    sinfo->invflags & IPT_CONNTRACK_REPLSRC,
  		    numeric);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_REPLDST) {
  		printf("%sctrepldst ", optpfx);
  
  		print_addr(
  		    (struct in_addr *)&sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
  		    &sinfo->dipmsk[IP_CT_DIR_REPLY],
  		    sinfo->invflags & IPT_CONNTRACK_REPLDST,
  		    numeric);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_STATUS) {
  		printf("%sctstatus ", optpfx);
          	if (sinfo->invflags & IPT_CONNTRACK_STATUS)
                  	printf("! ");
  		print_status(sinfo->statusmask);
  	}
  
  	if(sinfo->flags & IPT_CONNTRACK_EXPIRES) {
  		printf("%sctexpire ", optpfx);
          	if (sinfo->invflags & IPT_CONNTRACK_EXPIRES)
                  	printf("! ");
  
  #ifdef KERNEL_64_USERSPACE_32
          	if (sinfo->expires_max == sinfo->expires_min)
                  	printf("%llu ", sinfo->expires_min);
          	else
                  	printf("%llu:%llu ", sinfo->expires_min, sinfo->expires_max);
  #else
          	if (sinfo->expires_max == sinfo->expires_min)
                  	printf("%lu ", sinfo->expires_min);
          	else
                  	printf("%lu:%lu ", sinfo->expires_min, sinfo->expires_max);
  #endif
  	}
  }
  
  /* Prints out the matchinfo. */
  static void
  print(const struct ipt_ip *ip,
        const struct ipt_entry_match *match,
        int numeric)
  {
  	matchinfo_print(ip, match, numeric, "");
  }
  
  /* Saves the matchinfo in parsable form to stdout. */
  static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
  {
  	matchinfo_print(ip, match, 1, "--");
  }
  
  static struct iptables_match conntrack = { 
  	.next 		= NULL,
  	.name		= "conntrack",
  	.version	= IPTABLES_VERSION,
  	.size		= IPT_ALIGN(sizeof(struct ipt_conntrack_info)),
  	.userspacesize	= IPT_ALIGN(sizeof(struct ipt_conntrack_info)),
  	.help		= &help,
  	.parse		= &parse,
  	.final_check	= &final_check,
  	.print		= &print,
  	.save		= &save,
  	.extra_opts	= opts
  };
  
  void _init(void)
  {
  	register_match(&conntrack);
  }
  