general conntrack match module userspace support files

1 files changed, 517 insertions, 0 deletions

diff --git a/extensions/libipt_conntrack.c b/extensions/libipt_conntrack.c
new file mode 100644
index 00000000..9b639391
--- /dev/null
+++ b/extensions/libipt_conntrack.c
@@ -0,0 +1,517 @@
+/* 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>
+#include <linux/netfilter_ipv4/ipt_conntrack.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"conntrack match v%s options:\n"
+" [!] --ctstate [INVALID|ESTABLISHED|NEW|RELATED|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][,...]\n"
+"				Status(es) to match\n"
+" [!] --ctexpire time[:time]	Match remaining lifetime in seconds against\n"
+"				value or range of values (inclusive)\n"
+"\n", NETFILTER_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}
+};
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+	/* Can't cache this */
+	*nfcache |= NFC_UNKNOWN;
+}
+
+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, "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;
+	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);
+}
+
+
+static unsigned long
+parse_expire(const char *s)
+{
+	unsigned int len;
+	
+	if (string_to_number(s, 0, 0xFFFFFFFF, &len) == -1)
+		exit_error(PARAMETER_PROBLEM, "expire value invalid: `%s'\n", s);
+	else
+		return len;
+}
+
+/* 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) : 0xFFFFFFFF;
+	}
+	free(buffer);
+	
+	if (sinfo->expires_min > sinfo->expires_max)
+		exit_error(PARAMETER_PROBLEM,
+		           "expire min. range value `%lu' greater than max. "
+		           "range value `%lu'", sinfo->expires_min, sinfo->expires_max);
+	
+}
+
+/* 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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		parse_states(argv[optind-1], sinfo);
+		if (invert) {
+			sinfo->invflags |= IPT_CONNTRACK_STATE;
+		}
+		sinfo->flags |= IPT_CONNTRACK_STATE;
+		break;
+
+	case '2':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		parse_statuses(argv[optind-1], sinfo);
+		if (invert) {
+			sinfo->invflags |= IPT_CONNTRACK_STATUS;
+		}
+		sinfo->flags |= IPT_CONNTRACK_STATUS;
+		break;
+
+	case '8':
+		if (check_inverse(optarg, &invert))
+			optind++;
+
+		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_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 = ",";
+	}
+	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)
+               	fputc('!', stdout);
+
+	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)
+                	fputc('!', stdout);
+		print_state(sinfo->statemask);
+	}
+
+	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("%sctorigsrc ", 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("%sctorigdst ", 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_STATE)
+                	fputc('!', stdout);
+		print_status(sinfo->statusmask);
+	}
+
+	if(sinfo->flags & IPT_CONNTRACK_EXPIRES) {
+		printf("%sctexpire ", optpfx);
+        	if (sinfo->invflags & IPT_CONNTRACK_EXPIRES)
+                	fputc('!', stdout);
+
+        	if (sinfo->expires_max == sinfo->expires_min)
+                	printf("%lu ", sinfo->expires_min);
+        	else
+                	printf("%lu:%lu ", sinfo->expires_min, sinfo->expires_max);
+	}
+}
+
+/* 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, 0, "--");
+}
+
+static
+struct iptables_match conntrack
+= { NULL,
+    "conntrack",
+    NETFILTER_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_conntrack_info)),
+    IPT_ALIGN(sizeof(struct ipt_conntrack_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_match(&conntrack);
+}