Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1401 insertions, 0 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
new file mode 100644
index 000000000..5fa0e3730
--- /dev/null
+++ b/net/ipv6/exthdrs.c
@@ -0,0 +1,1401 @@
+// 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 <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 (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
+			break;
+		fallthrough;
+	case 2: /* send ICMP PARM PROB regardless and drop packet */
+		icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff,
+					 SKB_DROP_REASON_UNHANDLED_PROTO);
+		return false;
+	}
+
+drop:
+	kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);
+	return false;
+}
+
+static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
+static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
+#endif
+
+/* Parse tlv encoded option header (hop-by-hop or destination) */
+
+static bool ip6_parse_tlv(bool hopbyhop,
+			  struct sk_buff *skb,
+			  int max_count)
+{
+	int len = (skb_transport_header(skb)[1] + 1) << 3;
+	const unsigned char *nh = skb_network_header(skb);
+	int off = skb_network_header_len(skb);
+	bool disallow_unknowns = false;
+	int tlv_count = 0;
+	int padlen = 0;
+
+	if (unlikely(max_count < 0)) {
+		disallow_unknowns = true;
+		max_count = -max_count;
+	}
+
+	if (skb_transport_offset(skb) + len > skb_headlen(skb))
+		goto bad;
+
+	off += 2;
+	len -= 2;
+
+	while (len > 0) {
+		int optlen, i;
+
+		if (nh[off] == IPV6_TLV_PAD1) {
+			padlen++;
+			if (padlen > 7)
+				goto bad;
+			off++;
+			len--;
+			continue;
+		}
+		if (len < 2)
+			goto bad;
+		optlen = nh[off + 1] + 2;
+		if (optlen > len)
+			goto bad;
+
+		if (nh[off] == IPV6_TLV_PADN) {
+			/* RFC 2460 states that the purpose of PadN is
+			 * to align the containing header to multiples
+			 * of 8. 7 is therefore the highest valid value.
+			 * See also RFC 4942, Section 2.1.9.5.
+			 */
+			padlen += optlen;
+			if (padlen > 7)
+				goto bad;
+			/* RFC 4942 recommends receiving hosts to
+			 * actively check PadN payload to contain
+			 * only zeroes.
+			 */
+			for (i = 2; i < optlen; i++) {
+				if (nh[off + i] != 0)
+					goto bad;
+			}
+		} else {
+			tlv_count++;
+			if (tlv_count > max_count)
+				goto bad;
+
+			if (hopbyhop) {
+				switch (nh[off]) {
+				case IPV6_TLV_ROUTERALERT:
+					if (!ipv6_hop_ra(skb, off))
+						return false;
+					break;
+				case IPV6_TLV_IOAM:
+					if (!ipv6_hop_ioam(skb, off))
+						return false;
+					break;
+				case IPV6_TLV_JUMBO:
+					if (!ipv6_hop_jumbo(skb, off))
+						return false;
+					break;
+				case IPV6_TLV_CALIPSO:
+					if (!ipv6_hop_calipso(skb, off))
+						return false;
+					break;
+				default:
+					if (!ip6_tlvopt_unknown(skb, off,
+								disallow_unknowns))
+						return false;
+					break;
+				}
+			} else {
+				switch (nh[off]) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+				case IPV6_TLV_HAO:
+					if (!ipv6_dest_hao(skb, off))
+						return false;
+					break;
+#endif
+				default:
+					if (!ip6_tlvopt_unknown(skb, off,
+								disallow_unknowns))
+						return false;
+					break;
+				}
+			}
+			padlen = 0;
+		}
+		off += optlen;
+		len -= optlen;
+	}
+
+	if (len == 0)
+		return true;
+bad:
+	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
+	return false;
+}
+
+/*****************************
+  Destination options header.
+ *****************************/
+
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
+{
+	struct ipv6_destopt_hao *hao;
+	struct inet6_skb_parm *opt = IP6CB(skb);
+	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	SKB_DR(reason);
+	int ret;
+
+	if (opt->dsthao) {
+		net_dbg_ratelimited("hao duplicated\n");
+		goto discard;
+	}
+	opt->dsthao = opt->dst1;
+	opt->dst1 = 0;
+
+	hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
+
+	if (hao->length != 16) {
+		net_dbg_ratelimited("hao invalid option length = %d\n",
+				    hao->length);
+		SKB_DR_SET(reason, IP_INHDR);
+		goto discard;
+	}
+
+	if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
+		net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
+				    &hao->addr);
+		SKB_DR_SET(reason, INVALID_PROTO);
+		goto discard;
+	}
+
+	ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
+			       (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
+	if (unlikely(ret < 0)) {
+		SKB_DR_SET(reason, XFRM_POLICY);
+		goto discard;
+	}
+
+	if (skb_cloned(skb)) {
+		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+			goto discard;
+
+		/* update all variable using below by copied skbuff */
+		hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
+						  optoff);
+		ipv6h = ipv6_hdr(skb);
+	}
+
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->ip_summed = CHECKSUM_NONE;
+
+	swap(ipv6h->saddr, hao->addr);
+
+	if (skb->tstamp == 0)
+		__net_timestamp(skb);
+
+	return true;
+
+ discard:
+	kfree_skb_reason(skb, reason);
+	return false;
+}
+#endif
+
+static int ipv6_destopt_rcv(struct sk_buff *skb)
+{
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
+	struct inet6_skb_parm *opt = IP6CB(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+	__u16 dstbuf;
+#endif
+	struct dst_entry *dst = skb_dst(skb);
+	struct net *net = dev_net(skb->dev);
+	int extlen;
+
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
+	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
+				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
+		__IP6_INC_STATS(dev_net(dst->dev), idev,
+				IPSTATS_MIB_INHDRERRORS);
+fail_and_free:
+		kfree_skb(skb);
+		return -1;
+	}
+
+	extlen = (skb_transport_header(skb)[1] + 1) << 3;
+	if (extlen > net->ipv6.sysctl.max_dst_opts_len)
+		goto fail_and_free;
+
+	opt->lastopt = opt->dst1 = skb_network_header_len(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+	dstbuf = opt->dst1;
+#endif
+
+	if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
+		skb->transport_header += extlen;
+		opt = IP6CB(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+		opt->nhoff = dstbuf;
+#else
+		opt->nhoff = opt->dst1;
+#endif
+		return 1;
+	}
+
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+	return -1;
+}
+
+static void seg6_update_csum(struct sk_buff *skb)
+{
+	struct ipv6_sr_hdr *hdr;
+	struct in6_addr *addr;
+	__be32 from, to;
+
+	/* srh is at transport offset and seg_left is already decremented
+	 * but daddr is not yet updated with next segment
+	 */
+
+	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+	addr = hdr->segments + hdr->segments_left;
+
+	hdr->segments_left++;
+	from = *(__be32 *)hdr;
+
+	hdr->segments_left--;
+	to = *(__be32 *)hdr;
+
+	/* update skb csum with diff resulting from seg_left decrement */
+
+	update_csum_diff4(skb, from, to);
+
+	/* compute csum diff between current and next segment and update */
+
+	update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
+			   (__be32 *)addr);
+}
+
+static int ipv6_srh_rcv(struct sk_buff *skb)
+{
+	struct inet6_skb_parm *opt = IP6CB(skb);
+	struct net *net = dev_net(skb->dev);
+	struct ipv6_sr_hdr *hdr;
+	struct inet6_dev *idev;
+	struct in6_addr *addr;
+	int accept_seg6;
+
+	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+
+	idev = __in6_dev_get(skb->dev);
+
+	accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
+	if (accept_seg6 > idev->cnf.seg6_enabled)
+		accept_seg6 = idev->cnf.seg6_enabled;
+
+	if (!accept_seg6) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+	if (!seg6_hmac_validate_skb(skb)) {
+		kfree_skb(skb);
+		return -1;
+	}
+#endif
+
+looped_back:
+	if (hdr->segments_left == 0) {
+		if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
+			int offset = (hdr->hdrlen + 1) << 3;
+
+			skb_postpull_rcsum(skb, skb_network_header(skb),
+					   skb_network_header_len(skb));
+
+			if (!pskb_pull(skb, offset)) {
+				kfree_skb(skb);
+				return -1;
+			}
+			skb_postpull_rcsum(skb, skb_transport_header(skb),
+					   offset);
+
+			skb_reset_network_header(skb);
+			skb_reset_transport_header(skb);
+			skb->encapsulation = 0;
+			if (hdr->nexthdr == NEXTHDR_IPV4)
+				skb->protocol = htons(ETH_P_IP);
+			__skb_tunnel_rx(skb, skb->dev, net);
+
+			netif_rx(skb);
+			return -1;
+		}
+
+		opt->srcrt = skb_network_header_len(skb);
+		opt->lastopt = opt->srcrt;
+		skb->transport_header += (hdr->hdrlen + 1) << 3;
+		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+
+		return 1;
+	}
+
+	if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  ((&hdr->segments_left) -
+				   skb_network_header(skb)));
+		return -1;
+	}
+
+	if (skb_cloned(skb)) {
+		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
+			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+					IPSTATS_MIB_OUTDISCARDS);
+			kfree_skb(skb);
+			return -1;
+		}
+	}
+
+	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+
+	hdr->segments_left--;
+	addr = hdr->segments + hdr->segments_left;
+
+	skb_push(skb, sizeof(struct ipv6hdr));
+
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		seg6_update_csum(skb);
+
+	ipv6_hdr(skb)->daddr = *addr;
+
+	skb_dst_drop(skb);
+
+	ip6_route_input(skb);
+
+	if (skb_dst(skb)->error) {
+		dst_input(skb);
+		return -1;
+	}
+
+	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+		if (ipv6_hdr(skb)->hop_limit <= 1) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
+				    ICMPV6_EXC_HOPLIMIT, 0);
+			kfree_skb(skb);
+			return -1;
+		}
+		ipv6_hdr(skb)->hop_limit--;
+
+		skb_pull(skb, sizeof(struct ipv6hdr));
+		goto looped_back;
+	}
+
+	dst_input(skb);
+
+	return -1;
+}
+
+static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
+{
+	struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
+	struct inet6_skb_parm *opt = IP6CB(skb);
+	struct net *net = dev_net(skb->dev);
+	struct inet6_dev *idev;
+	struct ipv6hdr *oldhdr;
+	unsigned char *buf;
+	int accept_rpl_seg;
+	int i, err;
+	u64 n = 0;
+	u32 r;
+
+	idev = __in6_dev_get(skb->dev);
+
+	accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
+	if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
+		accept_rpl_seg = idev->cnf.rpl_seg_enabled;
+
+	if (!accept_rpl_seg) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+looped_back:
+	hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
+
+	if (hdr->segments_left == 0) {
+		if (hdr->nexthdr == NEXTHDR_IPV6) {
+			int offset = (hdr->hdrlen + 1) << 3;
+
+			skb_postpull_rcsum(skb, skb_network_header(skb),
+					   skb_network_header_len(skb));
+
+			if (!pskb_pull(skb, offset)) {
+				kfree_skb(skb);
+				return -1;
+			}
+			skb_postpull_rcsum(skb, skb_transport_header(skb),
+					   offset);
+
+			skb_reset_network_header(skb);
+			skb_reset_transport_header(skb);
+			skb->encapsulation = 0;
+
+			__skb_tunnel_rx(skb, skb->dev, net);
+
+			netif_rx(skb);
+			return -1;
+		}
+
+		opt->srcrt = skb_network_header_len(skb);
+		opt->lastopt = opt->srcrt;
+		skb->transport_header += (hdr->hdrlen + 1) << 3;
+		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+
+		return 1;
+	}
+
+	if (!pskb_may_pull(skb, sizeof(*hdr))) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+	n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
+	r = do_div(n, (16 - hdr->cmpri));
+	/* checks if calculation was without remainder and n fits into
+	 * unsigned char which is segments_left field. Should not be
+	 * higher than that.
+	 */
+	if (r || (n + 1) > 255) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+	if (hdr->segments_left > n + 1) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  ((&hdr->segments_left) -
+				   skb_network_header(skb)));
+		return -1;
+	}
+
+	if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
+						  hdr->cmpre))) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+	hdr->segments_left--;
+	i = n - hdr->segments_left;
+
+	buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
+	if (unlikely(!buf)) {
+		kfree_skb(skb);
+		return -1;
+	}
+
+	ohdr = (struct ipv6_rpl_sr_hdr *)buf;
+	ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
+	chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
+
+	if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
+	    (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
+		kfree_skb(skb);
+		kfree(buf);
+		return -1;
+	}
+
+	err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
+	if (err) {
+		icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
+		kfree_skb(skb);
+		kfree(buf);
+		return -1;
+	}
+
+	swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
+
+	ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
+
+	oldhdr = ipv6_hdr(skb);
+
+	skb_pull(skb, ((hdr->hdrlen + 1) << 3));
+	skb_postpull_rcsum(skb, oldhdr,
+			   sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
+	if (unlikely(!hdr->segments_left)) {
+		if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
+				     GFP_ATOMIC)) {
+			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
+			kfree_skb(skb);
+			kfree(buf);
+			return -1;
+		}
+
+		oldhdr = ipv6_hdr(skb);
+	}
+	skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
+	skb_reset_network_header(skb);
+	skb_mac_header_rebuild(skb);
+	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+	memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
+	memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
+
+	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
+	skb_postpush_rcsum(skb, ipv6_hdr(skb),
+			   sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
+
+	kfree(buf);
+
+	skb_dst_drop(skb);
+
+	ip6_route_input(skb);
+
+	if (skb_dst(skb)->error) {
+		dst_input(skb);
+		return -1;
+	}
+
+	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+		if (ipv6_hdr(skb)->hop_limit <= 1) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
+				    ICMPV6_EXC_HOPLIMIT, 0);
+			kfree_skb(skb);
+			return -1;
+		}
+		ipv6_hdr(skb)->hop_limit--;
+
+		skb_pull(skb, sizeof(struct ipv6hdr));
+		goto looped_back;
+	}
+
+	dst_input(skb);
+
+	return -1;
+}
+
+/********************************
+  Routing header.
+ ********************************/
+
+/* called with rcu_read_lock() */
+static int ipv6_rthdr_rcv(struct sk_buff *skb)
+{
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
+	struct inet6_skb_parm *opt = IP6CB(skb);
+	struct in6_addr *addr = NULL;
+	struct in6_addr daddr;
+	int n, i;
+	struct ipv6_rt_hdr *hdr;
+	struct rt0_hdr *rthdr;
+	struct net *net = dev_net(skb->dev);
+	int accept_source_route = net->ipv6.devconf_all->accept_source_route;
+
+	if (idev && accept_source_route > idev->cnf.accept_source_route)
+		accept_source_route = idev->cnf.accept_source_route;
+
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
+	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
+				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+		kfree_skb(skb);
+		return -1;
+	}
+
+	hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
+
+	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
+	    skb->pkt_type != PACKET_HOST) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+		kfree_skb(skb);
+		return -1;
+	}
+
+	switch (hdr->type) {
+	case IPV6_SRCRT_TYPE_4:
+		/* segment routing */
+		return ipv6_srh_rcv(skb);
+	case IPV6_SRCRT_TYPE_3:
+		/* rpl segment routing */
+		return ipv6_rpl_srh_rcv(skb);
+	default:
+		break;
+	}
+
+looped_back:
+	if (hdr->segments_left == 0) {
+		switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+		case IPV6_SRCRT_TYPE_2:
+			/* Silently discard type 2 header unless it was
+			 * processed by own
+			 */
+			if (!addr) {
+				__IP6_INC_STATS(net, idev,
+						IPSTATS_MIB_INADDRERRORS);
+				kfree_skb(skb);
+				return -1;
+			}
+			break;
+#endif
+		default:
+			break;
+		}
+
+		opt->lastopt = opt->srcrt = skb_network_header_len(skb);
+		skb->transport_header += (hdr->hdrlen + 1) << 3;
+		opt->dst0 = opt->dst1;
+		opt->dst1 = 0;
+		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+		return 1;
+	}
+
+	switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+	case IPV6_SRCRT_TYPE_2:
+		if (accept_source_route < 0)
+			goto unknown_rh;
+		/* Silently discard invalid RTH type 2 */
+		if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+			kfree_skb(skb);
+			return -1;
+		}
+		break;
+#endif
+	default:
+		goto unknown_rh;
+	}
+
+	/*
+	 *	This is the routing header forwarding algorithm from
+	 *	RFC 2460, page 16.
+	 */
+
+	n = hdr->hdrlen >> 1;
+
+	if (hdr->segments_left > n) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  ((&hdr->segments_left) -
+				   skb_network_header(skb)));
+		return -1;
+	}
+
+	/* We are about to mangle packet header. Be careful!
+	   Do not damage packets queued somewhere.
+	 */
+	if (skb_cloned(skb)) {
+		/* the copy is a forwarded packet */
+		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
+			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+					IPSTATS_MIB_OUTDISCARDS);
+			kfree_skb(skb);
+			return -1;
+		}
+		hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
+	}
+
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->ip_summed = CHECKSUM_NONE;
+
+	i = n - --hdr->segments_left;
+
+	rthdr = (struct rt0_hdr *) hdr;
+	addr = rthdr->addr;
+	addr += i - 1;
+
+	switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+	case IPV6_SRCRT_TYPE_2:
+		if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
+				     (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
+				     IPPROTO_ROUTING) < 0) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+			kfree_skb(skb);
+			return -1;
+		}
+		if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+			kfree_skb(skb);
+			return -1;
+		}
+		break;
+#endif
+	default:
+		break;
+	}
+
+	if (ipv6_addr_is_multicast(addr)) {
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+		kfree_skb(skb);
+		return -1;
+	}
+
+	daddr = *addr;
+	*addr = ipv6_hdr(skb)->daddr;
+	ipv6_hdr(skb)->daddr = daddr;
+
+	skb_dst_drop(skb);
+	ip6_route_input(skb);
+	if (skb_dst(skb)->error) {
+		skb_push(skb, skb->data - skb_network_header(skb));
+		dst_input(skb);
+		return -1;
+	}
+
+	if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
+		if (ipv6_hdr(skb)->hop_limit <= 1) {
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+			icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
+				    0);
+			kfree_skb(skb);
+			return -1;
+		}
+		ipv6_hdr(skb)->hop_limit--;
+		goto looped_back;
+	}
+
+	skb_push(skb, skb->data - skb_network_header(skb));
+	dst_input(skb);
+	return -1;
+
+unknown_rh:
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+	icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+			  (&hdr->type) - skb_network_header(skb));
+	return -1;
+}
+
+static const struct inet6_protocol rthdr_protocol = {
+	.handler	=	ipv6_rthdr_rcv,
+	.flags		=	INET6_PROTO_NOPOLICY,
+};
+
+static const struct inet6_protocol destopt_protocol = {
+	.handler	=	ipv6_destopt_rcv,
+	.flags		=	INET6_PROTO_NOPOLICY,
+};
+
+static const struct inet6_protocol nodata_protocol = {
+	.handler	=	dst_discard,
+	.flags		=	INET6_PROTO_NOPOLICY,
+};
+
+int __init ipv6_exthdrs_init(void)
+{
+	int ret;
+
+	ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+	if (ret)
+		goto out;
+
+	ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+	if (ret)
+		goto out_rthdr;
+
+	ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
+	if (ret)
+		goto out_destopt;
+
+out:
+	return ret;
+out_destopt:
+	inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+out_rthdr:
+	inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+	goto out;
+};
+
+void ipv6_exthdrs_exit(void)
+{
+	inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
+	inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+	inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+}
+
+/**********************************
+  Hop-by-hop options.
+ **********************************/
+
+/*
+ * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
+ */
+static inline struct net *ipv6_skb_net(struct sk_buff *skb)
+{
+	return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
+}
+
+/* Router Alert as of RFC 2711 */
+
+static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
+{
+	const unsigned char *nh = skb_network_header(skb);
+
+	if (nh[optoff + 1] == 2) {
+		IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
+		memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
+		return true;
+	}
+	net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
+			    nh[optoff + 1]);
+	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
+	return false;
+}
+
+/* IOAM */
+
+static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
+{
+	struct ioam6_trace_hdr *trace;
+	struct ioam6_namespace *ns;
+	struct ioam6_hdr *hdr;
+
+	/* Bad alignment (must be 4n-aligned) */
+	if (optoff & 3)
+		goto drop;
+
+	/* Ignore if IOAM is not enabled on ingress */
+	if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
+		goto ignore;
+
+	/* Truncated Option header */
+	hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
+	if (hdr->opt_len < 2)
+		goto drop;
+
+	switch (hdr->type) {
+	case IOAM6_TYPE_PREALLOC:
+		/* Truncated Pre-allocated Trace header */
+		if (hdr->opt_len < 2 + sizeof(*trace))
+			goto drop;
+
+		/* Malformed Pre-allocated Trace header */
+		trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
+		if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
+			goto drop;
+
+		/* Ignore if the IOAM namespace is unknown */
+		ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
+		if (!ns)
+			goto ignore;
+
+		if (!skb_valid_dst(skb))
+			ip6_route_input(skb);
+
+		ioam6_fill_trace_data(skb, ns, trace, true);
+		break;
+	default:
+		break;
+	}
+
+ignore:
+	return true;
+
+drop:
+	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
+	return false;
+}
+
+/* Jumbo payload */
+
+static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
+{
+	const unsigned char *nh = skb_network_header(skb);
+	SKB_DR(reason);
+	u32 pkt_len;
+
+	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
+		net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
+				    nh[optoff+1]);
+		SKB_DR_SET(reason, IP_INHDR);
+		goto drop;
+	}
+
+	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
+	if (pkt_len <= IPV6_MAXPLEN) {
+		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
+					 SKB_DROP_REASON_IP_INHDR);
+		return false;
+	}
+	if (ipv6_hdr(skb)->payload_len) {
+		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
+					 SKB_DROP_REASON_IP_INHDR);
+		return false;
+	}
+
+	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
+		SKB_DR_SET(reason, PKT_TOO_SMALL);
+		goto drop;
+	}
+
+	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
+		goto drop;
+
+	IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
+	return true;
+
+drop:
+	kfree_skb_reason(skb, reason);
+	return false;
+}
+
+/* CALIPSO RFC 5570 */
+
+static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
+{
+	const unsigned char *nh = skb_network_header(skb);
+
+	if (nh[optoff + 1] < 8)
+		goto drop;
+
+	if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
+		goto drop;
+
+	if (!calipso_validate(skb, nh + optoff))
+		goto drop;
+
+	return true;
+
+drop:
+	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
+	return false;
+}
+
+int ipv6_parse_hopopts(struct sk_buff *skb)
+{
+	struct inet6_skb_parm *opt = IP6CB(skb);
+	struct net *net = dev_net(skb->dev);
+	int extlen;
+
+	/*
+	 * skb_network_header(skb) is equal to skb->data, and
+	 * skb_network_header_len(skb) is always equal to
+	 * sizeof(struct ipv6hdr) by definition of
+	 * hop-by-hop options.
+	 */
+	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
+	    !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
+				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
+fail_and_free:
+		kfree_skb(skb);
+		return -1;
+	}
+
+	extlen = (skb_transport_header(skb)[1] + 1) << 3;
+	if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
+		goto fail_and_free;
+
+	opt->flags |= IP6SKB_HOPBYHOP;
+	if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
+		skb->transport_header += extlen;
+		opt = IP6CB(skb);
+		opt->nhoff = sizeof(struct ipv6hdr);
+		return 1;
+	}
+	return -1;
+}
+
+/*
+ *	Creating outbound headers.
+ *
+ *	"build" functions work when skb is filled from head to tail (datagram)
+ *	"push"	functions work when headers are added from tail to head (tcp)
+ *
+ *	In both cases we assume, that caller reserved enough room
+ *	for headers.
+ */
+
+static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
+			     struct ipv6_rt_hdr *opt,
+			     struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+	struct rt0_hdr *phdr, *ihdr;
+	int hops;
+
+	ihdr = (struct rt0_hdr *) opt;
+
+	phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
+	memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
+
+	hops = ihdr->rt_hdr.hdrlen >> 1;
+
+	if (hops > 1)
+		memcpy(phdr->addr, ihdr->addr + 1,
+		       (hops - 1) * sizeof(struct in6_addr));
+
+	phdr->addr[hops - 1] = **addr_p;
+	*addr_p = ihdr->addr;
+
+	phdr->rt_hdr.nexthdr = *proto;
+	*proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
+			     struct ipv6_rt_hdr *opt,
+			     struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+	struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
+	int plen, hops;
+
+	sr_ihdr = (struct ipv6_sr_hdr *)opt;
+	plen = (sr_ihdr->hdrlen + 1) << 3;
+
+	sr_phdr = skb_push(skb, plen);
+	memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
+
+	hops = sr_ihdr->first_segment + 1;
+	memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
+	       (hops - 1) * sizeof(struct in6_addr));
+
+	sr_phdr->segments[0] = **addr_p;
+	*addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
+
+	if (sr_ihdr->hdrlen > hops * 2) {
+		int tlvs_offset, tlvs_length;
+
+		tlvs_offset = (1 + hops * 2) << 3;
+		tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
+		memcpy((char *)sr_phdr + tlvs_offset,
+		       (char *)sr_ihdr + tlvs_offset, tlvs_length);
+	}
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+	if (sr_has_hmac(sr_phdr)) {
+		struct net *net = NULL;
+
+		if (skb->dev)
+			net = dev_net(skb->dev);
+		else if (skb->sk)
+			net = sock_net(skb->sk);
+
+		WARN_ON(!net);
+
+		if (net)
+			seg6_push_hmac(net, saddr, sr_phdr);
+	}
+#endif
+
+	sr_phdr->nexthdr = *proto;
+	*proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
+			    struct ipv6_rt_hdr *opt,
+			    struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+	switch (opt->type) {
+	case IPV6_SRCRT_TYPE_0:
+	case IPV6_SRCRT_STRICT:
+	case IPV6_SRCRT_TYPE_2:
+		ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
+		break;
+	case IPV6_SRCRT_TYPE_4:
+		ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
+		break;
+	default:
+		break;
+	}
+}
+
+static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
+{
+	struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
+
+	memcpy(h, opt, ipv6_optlen(opt));
+	h->nexthdr = *proto;
+	*proto = type;
+}
+
+void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
+			  u8 *proto,
+			  struct in6_addr **daddr, struct in6_addr *saddr)
+{
+	if (opt->srcrt) {
+		ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
+		/*
+		 * IPV6_RTHDRDSTOPTS is ignored
+		 * unless IPV6_RTHDR is set (RFC3542).
+		 */
+		if (opt->dst0opt)
+			ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+	}
+	if (opt->hopopt)
+		ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
+}
+
+void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
+{
+	if (opt->dst1opt)
+		ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
+}
+EXPORT_SYMBOL(ipv6_push_frag_opts);
+
+struct ipv6_txoptions *
+ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
+{
+	struct ipv6_txoptions *opt2;
+
+	opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
+	if (opt2) {
+		long dif = (char *)opt2 - (char *)opt;
+		memcpy(opt2, opt, opt->tot_len);
+		if (opt2->hopopt)
+			*((char **)&opt2->hopopt) += dif;
+		if (opt2->dst0opt)
+			*((char **)&opt2->dst0opt) += dif;
+		if (opt2->dst1opt)
+			*((char **)&opt2->dst1opt) += dif;
+		if (opt2->srcrt)
+			*((char **)&opt2->srcrt) += dif;
+		refcount_set(&opt2->refcnt, 1);
+	}
+	return opt2;
+}
+EXPORT_SYMBOL_GPL(ipv6_dup_options);
+
+static void ipv6_renew_option(int renewtype,
+			      struct ipv6_opt_hdr **dest,
+			      struct ipv6_opt_hdr *old,
+			      struct ipv6_opt_hdr *new,
+			      int newtype, char **p)
+{
+	struct ipv6_opt_hdr *src;
+
+	src = (renewtype == newtype ? new : old);
+	if (!src)
+		return;
+
+	memcpy(*p, src, ipv6_optlen(src));
+	*dest = (struct ipv6_opt_hdr *)*p;
+	*p += CMSG_ALIGN(ipv6_optlen(*dest));
+}
+
+/**
+ * ipv6_renew_options - replace a specific ext hdr with a new one.
+ *
+ * @sk: sock from which to allocate memory
+ * @opt: original options
+ * @newtype: option type to replace in @opt
+ * @newopt: new option of type @newtype to replace (user-mem)
+ *
+ * Returns a new set of options which is a copy of @opt with the
+ * option type @newtype replaced with @newopt.
+ *
+ * @opt may be NULL, in which case a new set of options is returned
+ * containing just @newopt.
+ *
+ * @newopt may be NULL, in which case the specified option type is
+ * not copied into the new set of options.
+ *
+ * The new set of options is allocated from the socket option memory
+ * buffer of @sk.
+ */
+struct ipv6_txoptions *
+ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
+		   int newtype, struct ipv6_opt_hdr *newopt)
+{
+	int tot_len = 0;
+	char *p;
+	struct ipv6_txoptions *opt2;
+
+	if (opt) {
+		if (newtype != IPV6_HOPOPTS && opt->hopopt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
+		if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
+		if (newtype != IPV6_RTHDR && opt->srcrt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
+		if (newtype != IPV6_DSTOPTS && opt->dst1opt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
+	}
+
+	if (newopt)
+		tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
+
+	if (!tot_len)
+		return NULL;
+
+	tot_len += sizeof(*opt2);
+	opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
+	if (!opt2)
+		return ERR_PTR(-ENOBUFS);
+
+	memset(opt2, 0, tot_len);
+	refcount_set(&opt2->refcnt, 1);
+	opt2->tot_len = tot_len;
+	p = (char *)(opt2 + 1);
+
+	ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
+			  (opt ? opt->hopopt : NULL),
+			  newopt, newtype, &p);
+	ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
+			  (opt ? opt->dst0opt : NULL),
+			  newopt, newtype, &p);
+	ipv6_renew_option(IPV6_RTHDR,
+			  (struct ipv6_opt_hdr **)&opt2->srcrt,
+			  (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
+			  newopt, newtype, &p);
+	ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
+			  (opt ? opt->dst1opt : NULL),
+			  newopt, newtype, &p);
+
+	opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
+			  (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
+			  (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
+	opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
+
+	return opt2;
+}
+
+struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
+					    struct ipv6_txoptions *opt)
+{
+	/*
+	 * ignore the dest before srcrt unless srcrt is being included.
+	 * --yoshfuji
+	 */
+	if (opt->dst0opt && !opt->srcrt) {
+		if (opt_space != opt) {
+			memcpy(opt_space, opt, sizeof(*opt_space));
+			opt = opt_space;
+		}
+		opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
+		opt->dst0opt = NULL;
+	}
+
+	return opt;
+}
+EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
+
+/**
+ * fl6_update_dst - update flowi destination address with info given
+ *                  by srcrt option, if any.
+ *
+ * @fl6: flowi6 for which daddr is to be updated
+ * @opt: struct ipv6_txoptions in which to look for srcrt opt
+ * @orig: copy of original daddr address if modified
+ *
+ * Returns NULL if no txoptions or no srcrt, otherwise returns orig
+ * and initial value of fl6->daddr set in orig
+ */
+struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
+				const struct ipv6_txoptions *opt,
+				struct in6_addr *orig)
+{
+	if (!opt || !opt->srcrt)
+		return NULL;
+
+	*orig = fl6->daddr;
+
+	switch (opt->srcrt->type) {
+	case IPV6_SRCRT_TYPE_0:
+	case IPV6_SRCRT_STRICT:
+	case IPV6_SRCRT_TYPE_2:
+		fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
+		break;
+	case IPV6_SRCRT_TYPE_4:
+	{
+		struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
+
+		fl6->daddr = srh->segments[srh->segments_left];
+		break;
+	}
+	default:
+		return NULL;
+	}
+
+	return orig;
+}
+EXPORT_SYMBOL_GPL(fl6_update_dst);