LOG Target for IPv6 (Jan Rekorajski)

1 files changed, 261 insertions, 0 deletions

diff --git a/extensions/libip6t_LOG.c b/extensions/libip6t_LOG.c
new file mode 100644
index 00000000..c147d1ca
--- /dev/null
+++ b/extensions/libip6t_LOG.c
@@ -0,0 +1,261 @@
+/* Shared library add-on to iptables to add LOG support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <getopt.h>
+#include <ip6tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_LOG.h>
+
+#define LOG_DEFAULT_LEVEL LOG_WARNING
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"LOG v%s options:\n"
+" --log-level level		Level of logging (numeric or see syslog.conf)\n"
+" --log-prefix prefix		Prefix log messages with this prefix.\n\n"
+" --log-tcp-sequence		Log TCP sequence numbers.\n\n"
+" --log-tcp-options		Log TCP options.\n\n"
+" --log-ip-options		Log IP options.\n\n",
+NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+	{ "log-level", 1, 0, '!' },
+	{ "log-prefix", 1, 0, '#' },
+	{ "log-tcp-sequence", 0, 0, '1' },
+	{ "log-tcp-options", 0, 0, '2' },
+	{ "log-ip-options", 0, 0, '3' },
+	{ 0 }
+};
+
+/* Initialize the target. */
+static void
+init(struct ip6t_entry_target *t, unsigned int *nfcache)
+{
+	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
+
+	loginfo->level = LOG_DEFAULT_LEVEL;
+
+	/* Can't cache this */
+	*nfcache |= NFC_UNKNOWN;
+}
+
+struct ip6t_log_names {
+	const char *name;
+	unsigned int level;
+};
+
+static struct ip6t_log_names ip6t_log_names[]
+= { { "alert", LOG_ALERT },
+    { "crit", LOG_CRIT },
+    { "debug", LOG_DEBUG },
+    { "emerg", LOG_EMERG },
+    { "error", LOG_ERR },		/* DEPRECATED */
+    { "info", LOG_INFO },
+    { "notice", LOG_NOTICE },
+    { "panic", LOG_EMERG },		/* DEPRECATED */
+    { "warning", LOG_WARNING }
+};
+
+static u_int8_t
+parse_level(const char *level)
+{
+	int lev;
+
+	lev = string_to_number(level, 0, 7);
+	if (lev == -1) {
+		unsigned int i = 0;
+
+		for (i = 0;
+		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
+		     i++) {
+			if (strncasecmp(level, ip6t_log_names[i].name,
+					strlen(level)) == 0) {
+				if (lev != -1)
+					exit_error(PARAMETER_PROBLEM,
+						   "log-level `%s' ambiguous",
+						   level);
+				lev = ip6t_log_names[i].level;
+			}
+		}
+
+		if (lev == -1)
+			exit_error(PARAMETER_PROBLEM,
+				   "log-level `%s' unknown", level);
+	}
+
+	return (u_int8_t)lev;
+}
+
+#define IP6T_LOG_OPT_LEVEL 0x01
+#define IP6T_LOG_OPT_PREFIX 0x02
+#define IP6T_LOG_OPT_TCPSEQ 0x04
+#define IP6T_LOG_OPT_TCPOPT 0x08
+#define IP6T_LOG_OPT_IPOPT 0x10
+
+/* 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 ip6t_entry *entry,
+      struct ip6t_entry_target **target)
+{
+	struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
+
+	switch (c) {
+	case '!':
+		if (*flags & IP6T_LOG_OPT_LEVEL)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --log-level twice");
+
+		if (check_inverse(optarg, &invert))
+			exit_error(PARAMETER_PROBLEM,
+				   "Unexpected `!' after --log-level");
+
+		loginfo->level = parse_level(optarg);
+		*flags |= IP6T_LOG_OPT_LEVEL;
+		break;
+
+	case '#':
+		if (*flags & IP6T_LOG_OPT_PREFIX)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --log-prefix twice");
+
+		if (check_inverse(optarg, &invert))
+			exit_error(PARAMETER_PROBLEM,
+				   "Unexpected `!' after --log-prefix");
+
+		if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
+			exit_error(PARAMETER_PROBLEM,
+				   "Maximum prefix length %u for --log-prefix",
+				   sizeof(loginfo->prefix) - 1);
+
+		strcpy(loginfo->prefix, optarg);
+		*flags |= IP6T_LOG_OPT_PREFIX;
+		break;
+
+	case '1':
+		if (*flags & IP6T_LOG_OPT_TCPSEQ)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --log-tcp-sequence "
+				   "twice");
+
+		loginfo->logflags |= IP6T_LOG_TCPSEQ;
+		*flags |= IP6T_LOG_OPT_TCPSEQ;
+		break;
+
+	case '2':
+		if (*flags & IP6T_LOG_OPT_TCPOPT)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --log-tcp-options twice");
+
+		loginfo->logflags |= IP6T_LOG_TCPOPT;
+		*flags |= IP6T_LOG_OPT_TCPOPT;
+		break;
+
+	case '3':
+		if (*flags & IP6T_LOG_OPT_IPOPT)
+			exit_error(PARAMETER_PROBLEM,
+				   "Can't specify --log-ip-options twice");
+
+		loginfo->logflags |= IP6T_LOG_IPOPT;
+		*flags |= IP6T_LOG_OPT_IPOPT;
+		break;
+
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+/* Final check; nothing. */
+static void final_check(unsigned int flags)
+{
+}
+
+/* Prints out the targinfo. */
+static void
+print(const struct ip6t_ip6 *ip,
+      const struct ip6t_entry_target *target,
+      int numeric)
+{
+	const struct ip6t_log_info *loginfo
+		= (const struct ip6t_log_info *)target->data;
+	unsigned int i = 0;
+
+	printf("LOG ");
+	if (numeric)
+		printf("flags %u level %u ",
+		       loginfo->logflags, loginfo->level);
+	else {
+		for (i = 0;
+		     i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
+		     i++) {
+			if (loginfo->level == ip6t_log_names[i].level) {
+				printf("level %s ", ip6t_log_names[i].name);
+				break;
+			}
+		}
+		if (i == sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names))
+			printf("UNKNOWN level %u ", loginfo->level);
+		if (loginfo->logflags & IP6T_LOG_TCPSEQ)
+			printf("tcp-sequence ");
+		if (loginfo->logflags & IP6T_LOG_TCPOPT)
+			printf("tcp-options ");
+		if (loginfo->logflags & IP6T_LOG_IPOPT)
+			printf("ip-options ");
+		if (loginfo->logflags & ~(IP6T_LOG_MASK))
+			printf("unknown-flags ");
+	}
+
+	if (strcmp(loginfo->prefix, "") != 0)
+		printf("prefix `%s' ", loginfo->prefix);
+}
+
+/* Saves the union ip6t_targinfo in parsable form to stdout. */
+static void
+save(const struct ip6t_ip6 *ip, const struct ip6t_entry_target *target)
+{
+	const struct ip6t_log_info *loginfo
+		= (const struct ip6t_log_info *)target->data;
+
+	if (strcmp(loginfo->prefix, "") != 0)
+		printf("--log-prefix %s ", loginfo->prefix);
+
+	if (loginfo->level != LOG_DEFAULT_LEVEL)
+		printf("--log-level %u ", loginfo->level);
+
+	if (loginfo->logflags & IP6T_LOG_TCPSEQ)
+		printf("--log-tcp-sequence ");
+	if (loginfo->logflags & IP6T_LOG_TCPOPT)
+		printf("--log-tcp-options ");
+	if (loginfo->logflags & IP6T_LOG_IPOPT)
+		printf("--log-ip-options ");
+}
+
+struct ip6tables_target log
+= { NULL,
+    "LOG",
+    NETFILTER_VERSION,
+    IP6T_ALIGN(sizeof(struct ip6t_log_info)),
+    IP6T_ALIGN(sizeof(struct ip6t_log_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_target6(&log);
+}