path: root/net/ipv6/exthdrs.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Extension Header handling for IPv6
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>
 *	Andi Kleen		<ak@muc.de>
 *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
 */

/* Changes:
 *	yoshfuji		: ensure not to overrun while parsing
 *				  tlv options.
 *	Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
 *	YOSHIFUJI Hideaki @USAGI  Register inbound extension header
 *				  handlers as inet6_protocol{}.
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/icmpv6.h>
#include <linux/slab.h>
#include <linux/export.h>

#include <net/dst.h>
#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/calipso.h>
#if IS_ENABLED(CONFIG_IPV6_MIP6)
#include <net/xfrm.h>
#endif
#include <linux/seg6.h>
#include <net/seg6.h>
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif
#include <net/rpl.h>
#include <linux/ioam6.h>
#include <linux/ioam6_genl.h>
#include <net/ioam6.h>
#include <net/dst_metadata.h>

#include <linux/uaccess.h>

/*********************
  Generic functions
 *********************/

/* An unknown option is detected, decide what to do */

static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
			       bool disallow_unknowns)
{
	if (disallow_unknowns) {
		/* If unknown TLVs are disallowed by configuration
		 * then always silently drop packet. Note this also
		 * means no ICMP parameter problem is sent which
		 * could be a good property to mitigate a reflection DOS
		 * attack.
		 */

		goto drop;
	}

	switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
	case 0: /* ignore */
		return true;

	case 1: /* drop packet */
		break;

	case 3: /* Send ICMP if not a multicast address and drop packet */
		/* Actually, it is redundant check. icmp_send
		   will recheck in any case.
		 */
		if