new HBH and DSTopts match for IPv6 by kisza

1 files changed, 285 insertions, 0 deletions

diff --git a/extensions/libip6t_hbh.c b/extensions/libip6t_hbh.c
new file mode 100644
index 0000000..a10d6a4
--- /dev/null
+++ b/extensions/libip6t_hbh.c
@@ -0,0 +1,285 @@
+/* Shared library add-on to ip6tables to add Hop-by-Hop and Dst headers support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <errno.h>
+#include <ip6tables.h>
+/*#include <linux/in6.h>*/
+#include <linux/netfilter_ipv6/ip6t_opts.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+                                        
+#define DEBUG		0
+#define HOPBYHOP	1
+#define UNAME		(HOPBYHOP ? "HBH" : "DST")
+#define LNAME		(HOPBYHOP ? "hbh" : "dst")
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"%s v%s options:\n"
+" --%s-len [!] length           total length of this header\n"
+" --%s-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
+"                               Options and its length (list, max: %d)\n", 
+UNAME , NETFILTER_VERSION, LNAME, LNAME, IP6T_OPTS_OPTSNR);
+}
+
+#if HOPBYHOP
+static struct option opts[] = {
+	{ "hbh-len", 1, 0, '1' },
+	{ "hbh-opts", 1, 0, '2' },
+	{ "hbh-not-strict", 1, 0, '3' },
+	{0}
+};
+#else
+static struct option opts[] = {
+	{ "dst-len", 1, 0, '1' },
+	{ "dst-opts", 1, 0, '2' },
+	{ "dst-not-strict", 1, 0, '3' },
+	{0}
+};
+#endif
+
+static u_int32_t
+parse_opts_num(const char *idstr, const char *typestr)
+{
+	unsigned long int id;
+	char* ep;
+
+	id =  strtoul(idstr,&ep,0) ;
+
+	if ( idstr == ep ) {
+		exit_error(PARAMETER_PROBLEM,
+			   "%s no valid digits in %s `%s'", UNAME, typestr, idstr);
+	}
+	if ( id == ULONG_MAX  && errno == ERANGE ) {
+		exit_error(PARAMETER_PROBLEM,
+			   "%s `%s' specified too big: would overflow",
+			   typestr, idstr);
+	}	
+	if ( *idstr != '\0'  && *ep != '\0' ) {
+		exit_error(PARAMETER_PROBLEM,
+			   "%s error parsing %s `%s'", UNAME, typestr, idstr);
+	}
+	return (u_int32_t) id;
+}
+
+static int
+parse_options(const char *optsstr, u_int16_t *opts)
+{
+        char *buffer, *cp, *next, *range;
+        unsigned int i;
+	
+	buffer = strdup(optsstr);
+        if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
+			
+        for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
+        {
+                next=strchr(cp, ',');
+                if (next) *next++='\0';
+                range = strchr(cp, ':');
+                if (range) {
+                        if (i == IP6T_OPTS_OPTSNR-1)
+                                exit_error(PARAMETER_PROBLEM,
+                                           "too many ports specified");
+                        *range++ = '\0';
+                }
+                opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8); 
+                if (range) {
+			if (opts[i] == 0)
+        			exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
+                        opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
+					0x000000FF);
+                } else {
+                        opts[i] |= (0x00FF);
+		}
+
+#if DEBUG
+		printf("opts str: %s %s\n", cp, range);
+		printf("opts opt: %04X\n", opts[i]);
+#endif
+	}
+        if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
+
+	free(buffer);
+
+#if DEBUG
+	printf("addr nr: %d\n", i);
+#endif
+
+	return i;
+}
+
+/* Initialize the match. */
+static void
+init(struct ip6t_entry_match *m, unsigned int *nfcache)
+{
+	struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
+
+	optinfo->hdrlen = 0;
+	optinfo->flags = 0;
+	optinfo->invflags = 0;
+	optinfo->optsnr = 0;
+}
+
+/* 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,
+      unsigned int *nfcache,
+      struct ip6t_entry_match **match)
+{
+	struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
+
+	switch (c) {
+	case '1':
+		if (*flags & IP6T_OPTS_LEN)
+			exit_error(PARAMETER_PROBLEM,
+				   "Only one `--%s-len' allowed", LNAME);
+		check_inverse(optarg, &invert, &optind, 0);
+		optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
+		if (invert)
+			optinfo->invflags |= IP6T_OPTS_INV_LEN;
+		optinfo->flags |= IP6T_OPTS_LEN;
+		*flags |= IP6T_OPTS_LEN;
+		break;
+	case '2':
+		if (*flags & IP6T_OPTS_OPTS)
+			exit_error(PARAMETER_PROBLEM,
+				   "Only one `--%s-opts' allowed", LNAME);
+                check_inverse(optarg, &invert, &optind, 0);
+                if (invert)
+                        exit_error(PARAMETER_PROBLEM,
+				" '!' not allowed with `--%s-opts'", LNAME);
+		optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
+		optinfo->flags |= IP6T_OPTS_OPTS;
+		*flags |= IP6T_OPTS_OPTS;
+		break;
+	case '3':
+		if (*flags & IP6T_OPTS_NSTRICT)
+			exit_error(PARAMETER_PROBLEM,
+				   "Only one `--%s-not-strict' allowed", LNAME);
+		if ( !(*flags & IP6T_OPTS_OPTS) )
+			exit_error(PARAMETER_PROBLEM,
+				   "`--%s-opts ...' required before `--%s-not-strict'", LNAME, LNAME);
+		optinfo->flags |= IP6T_OPTS_NSTRICT;
+		*flags |= IP6T_OPTS_NSTRICT;
+		break;
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+/* Final check; we don't care. */
+static void
+final_check(unsigned int flags)
+{
+}
+
+static void
+print_nums(const char *name, u_int32_t min, u_int32_t max,
+	    int invert)
+{
+	const char *inv = invert ? "!" : "";
+
+	if (min != 0 || max != 0xFFFFFFFF || invert) {
+		printf("%s", name);
+		if (min == max) {
+			printf(":%s", inv);
+			printf("%u", min);
+		} else {
+			printf("s:%s", inv);
+			printf("%u",min);
+			printf(":");
+			printf("%u",max);
+		}
+		printf(" ");
+	}
+}
+
+static void
+print_options(int optsnr, u_int16_t *optsp)
+{
+	unsigned int i;
+
+	for(i=0; i<optsnr; i++){
+		printf("%d", (optsp[i] & 0xFF00)>>8);
+		if ((optsp[i] & 0x00FF) != 0x00FF){
+			printf(":%d", (optsp[i] & 0x00FF));
+		} 
+		printf("%c", (i!=optsnr-1)?',':' ');
+	}
+}
+
+/* Prints out the union ip6t_matchinfo. */
+static void
+print(const struct ip6t_ip6 *ip,
+      const struct ip6t_entry_match *match, int numeric)
+{
+	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
+
+	printf("%s ", LNAME);
+	if (optinfo->flags & IP6T_OPTS_LEN) {
+		printf("length");
+		printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
+		printf("%u", optinfo->hdrlen);
+		printf(" ");
+	}
+	if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
+	print_options(optinfo->optsnr, optinfo->opts);
+	if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
+	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
+		printf("Unknown invflags: 0x%X ",
+		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);
+}
+
+/* Saves the union ip6t_matchinfo in parsable form to stdout. */
+static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
+{
+	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
+
+	if (optinfo->flags & IP6T_OPTS_LEN) {
+		printf("--%s-len %s%u ", LNAME, 
+			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "", 
+			optinfo->hdrlen);
+	}
+
+	if (optinfo->flags & IP6T_OPTS_OPTS) printf("--%s-opts ", LNAME);
+	print_options(optinfo->optsnr, optinfo->opts);
+	if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("--%s-not-strict ", LNAME);
+
+}
+
+static
+struct ip6tables_match optstruct
+= { NULL,
+#if HOPBYHOP
+    "hbh",
+#else
+    "dst",
+#endif
+    NETFILTER_VERSION,
+    IP6T_ALIGN(sizeof(struct ip6t_opts)),
+    IP6T_ALIGN(sizeof(struct ip6t_opts)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void
+_init(void)
+{
+	register_match6(&optstruct);
+}