--- /dev/null
+/* 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 ipv6header_help(void)
+{
+ printf(
+"ipv6header 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"
+"--soft The header CONTAINS the specified extensions\n");
+}
+
+static const struct option ipv6header_opts[] = {
+ { "header", 1, NULL, '1' },
+ { "soft", 0, NULL, '2' },
+ { .name = NULL }
+};
+
+static void ipv6header_init(struct xt_entry_match *m)
+{
+ struct ip6t_ipv6header_info *info = (struct ip6t_ipv6header_info *)m->data;
+
+ info->matchflags = 0x00;
+ info->invflags = 0x00;
+ info->modeflag = 0x00;
+}
+
+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
+#define IPV6_HDR_SOFT 0x02
+
+/* Parses command options; returns 0 if it ate an option */
+static int
+ipv6header_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_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");
+
+ check_inverse(optarg, &invert, &optind, 0);
+
+ if (! (info->matchflags = parse_header(argv[optind-1])) )
+ exit_error(PARAMETER_PROBLEM, "ip6t_ipv6header: cannot parse header names");
+
+ if (invert)
+ info->invflags |= 0xFF;
+ *flags |= IPV6_HDR_HEADER;
+ break;
+ case '2' :
+ /* Soft-mode requested? */
+ if (*flags & IPV6_HDR_SOFT)
+ exit_error(PARAMETER_PROBLEM,
+ "Only one `--soft' allowed");
+
+ info->modeflag |= 0xFF;
+ *flags |= IPV6_HDR_SOFT;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Checks the flags variable */
+static void ipv6header_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 ipv6header_print(const void *ip,
+ const struct xt_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(" ");
+ }
+ }
+
+ if (info->modeflag)
+ printf("soft ");
+
+ return;
+}
+
+/* Saves the match */
+static void ipv6header_save(const void *ip, const struct xt_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(" ");
+ if (info->modeflag)
+ printf("--soft ");
+
+ return;
+}
+
+static struct xtables_match ipv6header_mt6_reg = {
+ .name = "ipv6header",
+ .version = XTABLES_VERSION,
+ .family = PF_INET6,
+ .size = XT_ALIGN(sizeof(struct ip6t_ipv6header_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct ip6t_ipv6header_info)),
+ .help = ipv6header_help,
+ .init = ipv6header_init,
+ .parse = ipv6header_parse,
+ .final_check = ipv6header_check,
+ .print = ipv6header_print,
+ .save = ipv6header_save,
+ .extra_opts = ipv6header_opts,
+};
+
+void _init(void)
+{
+ xtables_register_match(&ipv6header_mt6_reg);
+}
git://git.onelab.eu / iptables.git / blobdiff