--- /dev/null
+/* Kernel module to match ROUTING parameters. */
+
+/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ipv6.h>
+#include <linux/types.h>
+#include <net/checksum.h>
+#include <net/ipv6.h>
+
+#include <asm/byteorder.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_rt.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Xtables: IPv6 Routing Header match");
+MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
+
+/* Returns 1 if the id is matched by the range, 0 otherwise */
+static inline bool
+segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
+{
+ bool r;
+ pr_debug("segsleft_match:%c 0x%x <= 0x%x <= 0x%x\n",
+ invert ? '!' : ' ', min, id, max);
+ r = (id >= min && id <= max) ^ invert;
+ pr_debug(" result %s\n", r ? "PASS" : "FAILED");
+ return r;
+}
+
+static bool rt_mt6(const struct sk_buff *skb, struct xt_action_param *par)
+{
+ struct ipv6_rt_hdr _route;
+ const struct ipv6_rt_hdr *rh;
+ const struct ip6t_rt *rtinfo = par->matchinfo;
+ unsigned int temp;
+ unsigned int ptr = 0;
+ unsigned int hdrlen = 0;
+ bool ret = false;
+ struct in6_addr _addr;
+ const struct in6_addr *ap;
+ int err;
+
+ err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL, NULL);
+ if (err < 0) {
+ if (err != -ENOENT)
+ par->hotdrop = true;
+ return false;
+ }
+
+ rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
+ if (rh == NULL) {
+ par->hotdrop = true;
+ return false;
+ }
+
+ hdrlen = ipv6_optlen(rh);
+ if (skb->len - ptr < hdrlen) {
+ /* Pcket smaller than its length field */
+ return false;
+ }
+
+ pr_debug("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen);
+ pr_debug("TYPE %04X ", rh->type);
+ pr_debug("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left);
+
+ pr_debug("IPv6 RT segsleft %02X ",
+ segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
+ rh->segments_left,
+ !!(rtinfo->invflags & IP6T_RT_INV_SGS)));
+ pr_debug("type %02X %02X %02X ",
+ rtinfo->rt_type, rh->type,
+ (!(rtinfo->flags & IP6T_RT_TYP) ||
+ ((rtinfo->rt_type == rh->type) ^
+ !!(rtinfo->invflags & IP6T_RT_INV_TYP))));
+ pr_debug("len %02X %04X %02X ",
+ rtinfo->hdrlen, hdrlen,
+ !(rtinfo->flags & IP6T_RT_LEN) ||
+ ((rtinfo->hdrlen == hdrlen) ^
+ !!(rtinfo->invflags & IP6T_RT_INV_LEN)));
+ pr_debug("res %02X %02X %02X ",
+ rtinfo->flags & IP6T_RT_RES,
+ ((const struct rt0_hdr *)rh)->reserved,
+ !((rtinfo->flags & IP6T_RT_RES) &&
+ (((const struct rt0_hdr *)rh)->reserved)));
+
+ ret = (rh != NULL) &&
+ (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
+ rh->segments_left,
+ !!(rtinfo->invflags & IP6T_RT_INV_SGS))) &&
+ (!(rtinfo->flags & IP6T_RT_LEN) ||
+ ((rtinfo->hdrlen == hdrlen) ^
+ !!(rtinfo->invflags & IP6T_RT_INV_LEN))) &&
+ (!(rtinfo->flags & IP6T_RT_TYP) ||
+ ((rtinfo->rt_type == rh->type) ^
+ !!(rtinfo->invflags & IP6T_RT_INV_TYP)));
+
+ if (ret && (rtinfo->flags & IP6T_RT_RES)) {
+ const u_int32_t *rp;
+ u_int32_t _reserved;
+ rp = skb_header_pointer(skb,
+ ptr + offsetof(struct rt0_hdr,
+ reserved),
+ sizeof(_reserved),
+ &_reserved);
+
+ ret = (*rp == 0);
+ }
+
+ pr_debug("#%d ", rtinfo->addrnr);
+ if (!(rtinfo->flags & IP6T_RT_FST)) {
+ return ret;
+ } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
+ pr_debug("Not strict ");
+ if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
+ pr_debug("There isn't enough space\n");
+ return false;
+ } else {
+ unsigned int i = 0;
+
+ pr_debug("#%d ", rtinfo->addrnr);
+ for (temp = 0;
+ temp < (unsigned int)((hdrlen - 8) / 16);
+ temp++) {
+ ap = skb_header_pointer(skb,
+ ptr
+ + sizeof(struct rt0_hdr)
+ + temp * sizeof(_addr),
+ sizeof(_addr),
+ &_addr);
+
+ BUG_ON(ap == NULL);
+
+ if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
+ pr_debug("i=%d temp=%d;\n", i, temp);
+ i++;
+ }
+ if (i == rtinfo->addrnr)
+ break;
+ }
+ pr_debug("i=%d #%d\n", i, rtinfo->addrnr);
+ if (i == rtinfo->addrnr)
+ return ret;
+ else
+ return false;
+ }
+ } else {
+ pr_debug("Strict ");
+ if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
+ pr_debug("There isn't enough space\n");
+ return false;
+ } else {
+ pr_debug("#%d ", rtinfo->addrnr);
+ for (temp = 0; temp < rtinfo->addrnr; temp++) {
+ ap = skb_header_pointer(skb,
+ ptr
+ + sizeof(struct rt0_hdr)
+ + temp * sizeof(_addr),
+ sizeof(_addr),
+ &_addr);
+ BUG_ON(ap == NULL);
+
+ if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
+ break;
+ }
+ pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr);
+ if (temp == rtinfo->addrnr &&
+ temp == (unsigned int)((hdrlen - 8) / 16))
+ return ret;
+ else
+ return false;
+ }
+ }
+
+ return false;
+}
+
+static int rt_mt6_check(const struct xt_mtchk_param *par)
+{
+ const struct ip6t_rt *rtinfo = par->matchinfo;
+
+ if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
+ pr_debug("unknown flags %X\n", rtinfo->invflags);
+ return -EINVAL;
+ }
+ if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
+ (!(rtinfo->flags & IP6T_RT_TYP) ||
+ (rtinfo->rt_type != 0) ||
+ (rtinfo->invflags & IP6T_RT_INV_TYP))) {
+ pr_debug("`--rt-type 0' required before `--rt-0-*'");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static struct xt_match rt_mt6_reg __read_mostly = {
+ .name = "rt",
+ .family = NFPROTO_IPV6,
+ .match = rt_mt6,
+ .matchsize = sizeof(struct ip6t_rt),
+ .checkentry = rt_mt6_check,
+ .me = THIS_MODULE,
+};
+
+static int __init rt_mt6_init(void)
+{
+ return xt_register_match(&rt_mt6_reg);
+}
+
+static void __exit rt_mt6_exit(void)
+{
+ xt_unregister_match(&rt_mt6_reg);
+}
+
+module_init(rt_mt6_init);
+module_exit(rt_mt6_exit);
Code Review / kvmfornfv.git / blobdiff