add new ipv6header match

diff --git a/extensions/.ipv6header-test6 b/extensions/.ipv6header-test6
new file mode 100755 (executable)
index 0000000..47f6f06
--- /dev/null
+++ b/extensions/.ipv6header-test6
@@ -0,0 +1,2 @@
+#!/bin/sh
+[ -f $KERNEL_DIR/net/ipv6/netfilter/ip6t_ipv6header.c -a -f $KERNEL_DIR/include/linux/netfilter_ipv6/ip6t_ipv6header.h ] && echo ipv6header

diff --git a/extensions/libip6t_ipv6header.c b/extensions/libip6t_ipv6header.c
new file mode 100644 (file)
index 0000000..fb990aa
--- /dev/null
+++ b/extensions/libip6t_ipv6header.c
@@ -0,0 +1,304 @@
+/* ipv6header match - matches IPv6 packets based
+on whether they contain certain headers */
+
+/* Original idea: Brad Chapman 
+ * Rewritten by: Andras Kis-Szabo <kisza@sch.bme.hu> */
+
+#include <getopt.h>
+#include <ip6tables.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netdb.h>
+#include <sys/types.h>
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_ipv6header.h>
+
+/* This maybe required 
+#include <linux/in.h>
+#include <linux/in6.h>
+*/
+
+
+/* A few hardcoded protocols for 'all' and in case the user has no
+ *    /etc/protocols */
+struct pprot {
+       char *name;
+       u_int8_t num;
+};
+
+struct numflag {
+       u_int8_t proto;
+       u_int8_t flag;
+};
+
+static const struct pprot chain_protos[] = {
+       { "hop-by-hop", IPPROTO_HOPOPTS },
+       { "protocol", IPPROTO_RAW },
+       { "hop", IPPROTO_HOPOPTS },
+       { "dst", IPPROTO_DSTOPTS },
+       { "route", IPPROTO_ROUTING },
+       { "frag", IPPROTO_FRAGMENT },
+       { "auth", IPPROTO_AH },
+       { "esp", IPPROTO_ESP },
+       { "none", IPPROTO_NONE },
+       { "prot", IPPROTO_RAW },
+       { "0", IPPROTO_HOPOPTS },
+       { "60", IPPROTO_DSTOPTS },
+       { "43", IPPROTO_ROUTING },
+       { "44", IPPROTO_FRAGMENT },
+       { "51", IPPROTO_AH },
+       { "50", IPPROTO_ESP },
+       { "59", IPPROTO_NONE },
+       { "255", IPPROTO_RAW },
+       /* { "all", 0 }, */
+};
+
+static const struct numflag chain_flags[] = {
+       { IPPROTO_HOPOPTS, MASK_HOPOPTS },
+       { IPPROTO_DSTOPTS, MASK_DSTOPTS },
+       { IPPROTO_ROUTING, MASK_ROUTING },
+       { IPPROTO_FRAGMENT, MASK_FRAGMENT },
+       { IPPROTO_AH, MASK_AH },
+       { IPPROTO_ESP, MASK_ESP },
+       { IPPROTO_NONE, MASK_NONE },
+       { IPPROTO_RAW, MASK_PROTO },
+};
+
+static char *
+proto_to_name(u_int8_t proto, int nolookup)
+{
+        unsigned int i;
+
+        if (proto && !nolookup) {
+                struct protoent *pent = getprotobynumber(proto);
+                if (pent)
+                        return pent->p_name;
+        }
+
+        for (i = 0; i < sizeof(chain_protos)/sizeof(struct pprot); i++)
+                if (chain_protos[i].num == proto)
+                        return chain_protos[i].name;
+
+        return NULL;
+}
+
+static u_int16_t
+name_to_proto(const char *s)
+{
+        unsigned int proto=0;
+        struct protoent *pent;
+
+        if ((pent = getprotobyname(s)))
+               proto = pent->p_proto;
+        else {
+               unsigned int i;
+               for (i = 0;
+                       i < sizeof(chain_protos)/sizeof(struct pprot);
+                       i++) {
+                       if (strcmp(s, chain_protos[i].name) == 0) {
+                               proto = chain_protos[i].num;
+                               break;
+                       }
+               }
+
+               if (i == sizeof(chain_protos)/sizeof(struct pprot))
+                       exit_error(PARAMETER_PROBLEM,
+                               "unknown header `%s' specified",
+                               s);
+        }
+
+        return (u_int16_t)proto;
+}
+
+static unsigned int 
+add_proto_to_mask(int proto){
+       unsigned int i=0, flag=0;
+
+       for (i = 0;
+               i < sizeof(chain_flags)/sizeof(struct numflag);
+               i++) {
+                       if (proto == chain_flags[i].proto){
+                               flag = chain_flags[i].flag;
+                               break;
+                       }
+       }
+
+       if (i == sizeof(chain_flags)/sizeof(struct numflag))
+               exit_error(PARAMETER_PROBLEM,
+               "unknown header `%d' specified",
+               proto);
+       
+       return flag;
+}      
+
+static void
+help(void)
+{
+       printf(
+"ipv6header v%s match options:\n"
+"--header [!] headers     Type of header to match, by name\n"
+"                         names: hop,dst,route,frag,auth,esp,none,proto\n"
+"                    long names: hop-by-hop,ipv6-opts,ipv6-route,\n"
+"                                ipv6-frag,ah,esp,ipv6-nonxt,protocol\n"
+"                       numbers: 0,60,43,44,51,50,59\n",
+       NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+       { "header", 1, 0, '1' },
+       { 0 }
+};
+
+static void
+init(struct ip6t_entry_match *m, unsigned int *nfcache)
+{
+       struct ip6t_ipv6header_info *info = (struct ip6t_ipv6header_info *)m->data;
+
+       info->matchflags = 0x00;
+       info->invflags = 0x00;
+       /* No caching (yet) */
+       *nfcache |= NFC_UNKNOWN;
+}
+
+static unsigned int
+parse_header(const char *flags) {
+        unsigned int ret = 0;
+        char *ptr;
+        char *buffer;
+
+        buffer = strdup(flags);
+
+        for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) 
+               ret |= add_proto_to_mask(name_to_proto(ptr));
+                
+        free(buffer);
+        return ret;
+}
+
+#define IPV6_HDR_HEADER 0x01
+
+/* Parses command options; returns 0 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_ipv6header_info *info = (struct ip6t_ipv6header_info *)(*match)->data;
+
+       switch (c) {
+               case '1' : 
+                       /* Parse the provided header names */
+                       if (*flags & IPV6_HDR_HEADER)
+                               exit_error(PARAMETER_PROBLEM,
+                                       "Only one `--header' allowed");
+
+                       if (check_inverse(optarg, &invert))
+                               optind++;
+
+                       if (! (info->matchflags = parse_header(argv[optind-1])) )
+                               exit_error(PARAMETER_PROBLEM, "ip6t_ipv6header: cannot parse header names");
+
+                       if (invert) 
+                               info->invflags |= 255;
+
+                       *flags |= IPV6_HDR_HEADER;
+
+                       break;
+               default:
+                       return 0;
+       }
+
+       return 1;
+}
+
+/* Checks the flags variable */
+static void
+final_check(unsigned int flags)
+{
+       if (!flags) exit_error(PARAMETER_PROBLEM, "ip6t_ipv6header: no options specified");
+}
+
+static void
+print_header(u_int8_t flags){
+        int have_flag = 0;
+
+        while (flags) {
+                unsigned int i;
+
+                for (i = 0; (flags & chain_flags[i].flag) == 0; i++);
+
+                if (have_flag)
+                        printf(",");
+
+                printf("%s", proto_to_name(chain_flags[i].proto,0));
+                have_flag = 1;
+
+                flags &= ~chain_flags[i].flag;
+        }
+
+        if (!have_flag)
+                printf("NONE");
+}
+
+/* Prints out the match */
+static void
+print(const struct ip6t_ip6 *ip,
+      const struct ip6t_entry_match *match,
+      int numeric)
+{
+       const struct ip6t_ipv6header_info *info = (const struct ip6t_ipv6header_info *)match->data;
+       printf("ipv6header ");
+
+        if (info->matchflags || info->invflags) {
+                printf("flags:%s", info->invflags ? "!" : "");
+                if (numeric)
+                        printf("0x%02X ", info->matchflags);
+                else {
+                        print_header(info->matchflags);
+                        printf(" ");
+                }
+        }
+
+       return;
+}
+
+/* Saves the match */
+static void
+save(const struct ip6t_ip6 *ip,
+     const struct ip6t_entry_match *match)
+{
+
+       const struct ip6t_ipv6header_info *info = (const struct ip6t_ipv6header_info *)match->data;
+
+       printf("--header ");
+       printf("%s", info->invflags ? "!" : "");
+       print_header(info->matchflags);
+       printf(" ");
+
+       return;
+}
+
+static
+struct ip6tables_match ipv6header
+= { NULL,
+    "ipv6header",
+    NETFILTER_VERSION,
+    IP6T_ALIGN(sizeof(struct ip6t_ipv6header_info)),
+    IP6T_ALIGN(sizeof(struct ip6t_ipv6header_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+       register_match6(&ipv6header);
+}