exthdrs.c 22.3 KB
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/*
 *	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>
 *
 *	$Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/* Changes:
19
 *	yoshfuji		: ensure not to overrun while parsing
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 *				  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 <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>
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#ifdef CONFIG_IPV6_MIP6
#include <net/xfrm.h>
#endif
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#include <asm/uaccess.h>

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int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
{
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	const unsigned char *nh = skb_network_header(skb);
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	int packet_len = skb->tail - skb->network_header;
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	struct ipv6_opt_hdr *hdr;
	int len;

	if (offset + 2 > packet_len)
		goto bad;
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	hdr = (struct ipv6_opt_hdr *)(nh + offset);
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	len = ((hdr->hdrlen + 1) << 3);

	if (offset + len > packet_len)
		goto bad;

	offset += 2;
	len -= 2;

	while (len > 0) {
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		int opttype = nh[offset];
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		int optlen;

		if (opttype == type)
			return offset;

		switch (opttype) {
		case IPV6_TLV_PAD0:
			optlen = 1;
			break;
		default:
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			optlen = nh[offset + 1] + 2;
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			if (optlen > len)
				goto bad;
			break;
		}
		offset += optlen;
		len -= optlen;
	}
	/* not_found */
 bad:
	return -1;
}

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/*
 *	Parsing tlv encoded headers.
 *
 *	Parsing function "func" returns 1, if parsing succeed
 *	and 0, if it failed.
 *	It MUST NOT touch skb->h.
 */

struct tlvtype_proc {
	int	type;
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	int	(*func)(struct sk_buff **skbp, int offset);
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};

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

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

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static int ip6_tlvopt_unknown(struct sk_buff **skbp, int optoff)
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{
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	struct sk_buff *skb = *skbp;

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	switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
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	case 0: /* ignore */
		return 1;

	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.
		 */
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		if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
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			break;
	case 2: /* send ICMP PARM PROB regardless and drop packet */
		icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
		return 0;
	};

	kfree_skb(skb);
	return 0;
}

/* Parse tlv encoded option header (hop-by-hop or destination) */

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static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
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{
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	struct sk_buff *skb = *skbp;
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	struct tlvtype_proc *curr;
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	const unsigned char *nh = skb_network_header(skb);
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	int off = skb_network_header_len(skb);
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	int len = (skb_transport_header(skb)[1] + 1) << 3;
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	if (skb_transport_offset(skb) + len > skb_headlen(skb))
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		goto bad;

	off += 2;
	len -= 2;

	while (len > 0) {
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		int optlen = nh[off + 1] + 2;
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		switch (nh[off]) {
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		case IPV6_TLV_PAD0:
			optlen = 1;
			break;

		case IPV6_TLV_PADN:
			break;

		default: /* Other TLV code so scan list */
			if (optlen > len)
				goto bad;
			for (curr=procs; curr->type >= 0; curr++) {
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				if (curr->type == nh[off]) {
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					/* type specific length/alignment
					   checks will be performed in the
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					   func(). */
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					if (curr->func(skbp, off) == 0)
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						return 0;
					break;
				}
			}
			if (curr->type < 0) {
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				if (ip6_tlvopt_unknown(skbp, off) == 0)
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					return 0;
			}
			break;
		}
		off += optlen;
		len -= optlen;
	}
	if (len == 0)
		return 1;
bad:
	kfree_skb(skb);
	return 0;
}

/*****************************
  Destination options header.
 *****************************/

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#ifdef CONFIG_IPV6_MIP6
static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
{
	struct sk_buff *skb = *skbp;
	struct ipv6_destopt_hao *hao;
	struct inet6_skb_parm *opt = IP6CB(skb);
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	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
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	struct in6_addr tmp_addr;
	int ret;

	if (opt->dsthao) {
		LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
		goto discard;
	}
	opt->dsthao = opt->dst1;
	opt->dst1 = 0;

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	hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
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	if (hao->length != 16) {
		LIMIT_NETDEBUG(
			KERN_DEBUG "hao invalid option length = %d\n", hao->length);
		goto discard;
	}

	if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
		LIMIT_NETDEBUG(
			KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr));
		goto discard;
	}

	ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
			       (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
	if (unlikely(ret < 0))
		goto discard;

	if (skb_cloned(skb)) {
		struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
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		struct inet6_skb_parm *opt2;

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		if (skb2 == NULL)
			goto discard;

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		opt2 = IP6CB(skb2);
		memcpy(opt2, opt, sizeof(*opt2));

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		kfree_skb(skb);

		/* update all variable using below by copied skbuff */
		*skbp = skb = skb2;
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		hao = (struct ipv6_destopt_hao *)(skb_network_header(skb2) +
						  optoff);
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		ipv6h = ipv6_hdr(skb2);
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	}

	if (skb->ip_summed == CHECKSUM_COMPLETE)
		skb->ip_summed = CHECKSUM_NONE;

	ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
	ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
	ipv6_addr_copy(&hao->addr, &tmp_addr);

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	if (skb->tstamp.tv64 == 0)
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		__net_timestamp(skb);

	return 1;

 discard:
	kfree_skb(skb);
	return 0;
}
#endif

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static struct tlvtype_proc tlvprocdestopt_lst[] = {
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#ifdef CONFIG_IPV6_MIP6
	{
		.type	= IPV6_TLV_HAO,
		.func	= ipv6_dest_hao,
	},
#endif
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	{-1,			NULL}
};

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static int ipv6_destopt_rcv(struct sk_buff **skbp)
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{
	struct sk_buff *skb = *skbp;
	struct inet6_skb_parm *opt = IP6CB(skb);
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#ifdef CONFIG_IPV6_MIP6
	__u16 dstbuf;
#endif
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	struct dst_entry *dst;
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	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
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				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
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		kfree_skb(skb);
		return -1;
	}

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	opt->lastopt = opt->dst1 = skb_network_header_len(skb);
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#ifdef CONFIG_IPV6_MIP6
	dstbuf = opt->dst1;
#endif
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	dst = dst_clone(skb->dst);
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	if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) {
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		dst_release(dst);
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		skb = *skbp;
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		skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
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		opt = IP6CB(skb);
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#ifdef CONFIG_IPV6_MIP6
		opt->nhoff = dstbuf;
#else
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		opt->nhoff = opt->dst1;
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#endif
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		return 1;
	}

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	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
	dst_release(dst);
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	return -1;
}

static struct inet6_protocol destopt_protocol = {
	.handler	=	ipv6_destopt_rcv,
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	.flags		=	INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
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};

void __init ipv6_destopt_init(void)
{
	if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
		printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
}

/********************************
  NONE header. No data in packet.
 ********************************/

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static int ipv6_nodata_rcv(struct sk_buff **skbp)
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{
	struct sk_buff *skb = *skbp;

	kfree_skb(skb);
	return 0;
}

static struct inet6_protocol nodata_protocol = {
	.handler	=	ipv6_nodata_rcv,
	.flags		=	INET6_PROTO_NOPOLICY,
};

void __init ipv6_nodata_init(void)
{
	if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
		printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
}

/********************************
  Routing header.
 ********************************/

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static int ipv6_rthdr_rcv(struct sk_buff **skbp)
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{
	struct sk_buff *skb = *skbp;
	struct inet6_skb_parm *opt = IP6CB(skb);
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	struct in6_addr *addr = NULL;
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	struct in6_addr daddr;
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	struct inet6_dev *idev;
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	int n, i;
	struct ipv6_rt_hdr *hdr;
	struct rt0_hdr *rthdr;
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	int accept_source_route = ipv6_devconf.accept_source_route;

	if (accept_source_route < 0 ||
	    ((idev = in6_dev_get(skb->dev)) == NULL)) {
		kfree_skb(skb);
		return -1;
	}
	if (idev->cnf.accept_source_route < 0) {
		in6_dev_put(idev);
		kfree_skb(skb);
		return -1;
	}

	if (accept_source_route > idev->cnf.accept_source_route)
		accept_source_route = idev->cnf.accept_source_route;

	in6_dev_put(idev);
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	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
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				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
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		kfree_skb(skb);
		return -1;
	}

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	hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
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	switch (hdr->type) {
#ifdef CONFIG_IPV6_MIP6
		break;
#endif
	case IPV6_SRCRT_TYPE_0:
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		if (accept_source_route > 0)
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			break;
		kfree_skb(skb);
		return -1;
	default:
		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
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		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
				  (&hdr->type) - skb_network_header(skb));
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		return -1;
	}

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	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
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	    skb->pkt_type != PACKET_HOST) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INADDRERRORS);
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		kfree_skb(skb);
		return -1;
	}

looped_back:
	if (hdr->segments_left == 0) {
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		switch (hdr->type) {
#ifdef CONFIG_IPV6_MIP6
		case IPV6_SRCRT_TYPE_2:
			/* Silently discard type 2 header unless it was
			 * processed by own
			 */
			if (!addr) {
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				IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
						 IPSTATS_MIB_INADDRERRORS);
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				kfree_skb(skb);
				return -1;
			}
			break;
#endif
		default:
			break;
		}

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		opt->lastopt = opt->srcrt = skb_network_header_len(skb);
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		skb->transport_header += (hdr->hdrlen + 1) << 3;
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		opt->dst0 = opt->dst1;
		opt->dst1 = 0;
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		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
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		return 1;
	}

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	switch (hdr->type) {
	case IPV6_SRCRT_TYPE_0:
		if (hdr->hdrlen & 0x01) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INHDRERRORS);
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			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
					  ((&hdr->hdrlen) -
					   skb_network_header(skb)));
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			return -1;
		}
		break;
#ifdef CONFIG_IPV6_MIP6
	case IPV6_SRCRT_TYPE_2:
		/* Silently discard invalid RTH type 2 */
		if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INHDRERRORS);
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			kfree_skb(skb);
			return -1;
		}
		break;
#endif
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	}

	/*
	 *	This is the routing header forwarding algorithm from
	 *	RFC 2460, page 16.
	 */

	n = hdr->hdrlen >> 1;

	if (hdr->segments_left > n) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
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		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
				  ((&hdr->segments_left) -
				   skb_network_header(skb)));
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		return -1;
	}

	/* We are about to mangle packet header. Be careful!
	   Do not damage packets queued somewhere.
	 */
	if (skb_cloned(skb)) {
		struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
		/* the copy is a forwarded packet */
		if (skb2 == NULL) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_OUTDISCARDS);
			kfree_skb(skb);
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			return -1;
		}
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		kfree_skb(skb);
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		*skbp = skb = skb2;
		opt = IP6CB(skb2);
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		hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb2);
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	}

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	if (skb->ip_summed == CHECKSUM_COMPLETE)
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		skb->ip_summed = CHECKSUM_NONE;

	i = n - --hdr->segments_left;

	rthdr = (struct rt0_hdr *) hdr;
	addr = rthdr->addr;
	addr += i - 1;

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	switch (hdr->type) {
#ifdef CONFIG_IPV6_MIP6
	case IPV6_SRCRT_TYPE_2:
		if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
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				     (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
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				     IPPROTO_ROUTING) < 0) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INADDRERRORS);
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			kfree_skb(skb);
			return -1;
		}
		if (!ipv6_chk_home_addr(addr)) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INADDRERRORS);
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			kfree_skb(skb);
			return -1;
		}
		break;
#endif
	default:
		break;
	}

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	if (ipv6_addr_is_multicast(addr)) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INADDRERRORS);
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		kfree_skb(skb);
		return -1;
	}

	ipv6_addr_copy(&daddr, addr);
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	ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
	ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
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	dst_release(xchg(&skb->dst, NULL));
	ip6_route_input(skb);
	if (skb->dst->error) {
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		skb_push(skb, skb->data - skb_network_header(skb));
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		dst_input(skb);
		return -1;
	}

	if (skb->dst->dev->flags&IFF_LOOPBACK) {
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		if (ipv6_hdr(skb)->hop_limit <= 1) {
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			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INHDRERRORS);
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			icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
				    0, skb->dev);
			kfree_skb(skb);
			return -1;
		}
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		ipv6_hdr(skb)->hop_limit--;
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		goto looped_back;
	}

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	skb_push(skb, skb->data - skb_network_header(skb));
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	dst_input(skb);
	return -1;
}

static struct inet6_protocol rthdr_protocol = {
	.handler	=	ipv6_rthdr_rcv,
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	.flags		=	INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
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};

void __init ipv6_rthdr_init(void)
{
	if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
		printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
};

/*
   This function inverts received rthdr.
   NOTE: specs allow to make it automatically only if
   packet authenticated.

   I will not discuss it here (though, I am really pissed off at
   this stupid requirement making rthdr idea useless)

   Actually, it creates severe problems  for us.
   Embryonic requests has no associated sockets,
   so that user have no control over it and
   cannot not only to set reply options, but
   even to know, that someone wants to connect
   without success. :-(

   For now we need to test the engine, so that I created
   temporary (or permanent) backdoor.
   If listening socket set IPV6_RTHDR to 2, then we invert header.
610
						   --ANK (980729)
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 */

struct ipv6_txoptions *
ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
{
	/* Received rthdr:

	   [ H1 -> H2 -> ... H_prev ]  daddr=ME

	   Inverted result:
	   [ H_prev -> ... -> H1 ] daddr =sender

	   Note, that IP output engine will rewrite this rthdr
	   by rotating it left by one addr.
	 */

	int n, i;
	struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr;
	struct rt0_hdr *irthdr;
	struct ipv6_txoptions *opt;
	int hdrlen = ipv6_optlen(hdr);

	if (hdr->segments_left ||
	    hdr->type != IPV6_SRCRT_TYPE_0 ||
	    hdr->hdrlen & 0x01)
		return NULL;

	n = hdr->hdrlen >> 1;
	opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC);
	if (opt == NULL)
		return NULL;
	memset(opt, 0, sizeof(*opt));
	opt->tot_len = sizeof(*opt) + hdrlen;
	opt->srcrt = (void*)(opt+1);
	opt->opt_nflen = hdrlen;

	memcpy(opt->srcrt, hdr, sizeof(*hdr));
	irthdr = (struct rt0_hdr*)opt->srcrt;
649
	irthdr->reserved = 0;
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	opt->srcrt->segments_left = n;
	for (i=0; i<n; i++)
		memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16);
	return opt;
}

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EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);

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/**********************************
  Hop-by-hop options.
 **********************************/

/* Router Alert as of RFC 2711 */

664
static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
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{
666
	struct sk_buff *skb = *skbp;
667
	const unsigned char *nh = skb_network_header(skb);
668

669
	if (nh[optoff + 1] == 2) {
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		IP6CB(skb)->ra = optoff;
		return 1;
	}
673
	LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
674
		       nh[optoff + 1]);
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	kfree_skb(skb);
	return 0;
}

/* Jumbo payload */

681
static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
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{
683
	struct sk_buff *skb = *skbp;
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	const unsigned char *nh = skb_network_header(skb);
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	u32 pkt_len;

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	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
688
		LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
689
			       nh[optoff+1]);
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
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		goto drop;
	}

695
	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
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	if (pkt_len <= IPV6_MAXPLEN) {
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		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
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		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
		return 0;
	}
701
	if (ipv6_hdr(skb)->payload_len) {
702
		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
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		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
		return 0;
	}

	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
708
		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS);
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		goto drop;
	}
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	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
		goto drop;

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	return 1;

drop:
	kfree_skb(skb);
	return 0;
}

static struct tlvtype_proc tlvprochopopt_lst[] = {
	{
		.type	= IPV6_TLV_ROUTERALERT,
		.func	= ipv6_hop_ra,
	},
	{
		.type	= IPV6_TLV_JUMBO,
		.func	= ipv6_hop_jumbo,
	},
	{ -1, }
};

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int ipv6_parse_hopopts(struct sk_buff **skbp)
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{
736
	struct sk_buff *skb = *skbp;
737 738
	struct inet6_skb_parm *opt = IP6CB(skb);

739
	/*
740
	 * skb_network_header(skb) is equal to skb->data, and
741
	 * skb_network_header_len(skb) is always equal to
742 743 744 745
	 * sizeof(struct ipv6hdr) by definition of
	 * hop-by-hop options.
	 */
	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
746 747
	    !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
748 749 750 751
		kfree_skb(skb);
		return -1;
	}

752
	opt->hop = sizeof(struct ipv6hdr);
753 754
	if (ip6_parse_tlv(tlvprochopopt_lst, skbp)) {
		skb = *skbp;
755
		skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
756
		opt = IP6CB(skb);
757
		opt->nhoff = sizeof(struct ipv6hdr);
758
		return 1;
759
	}
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	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_rthdr(struct sk_buff *skb, u8 *proto,
			    struct ipv6_rt_hdr *opt,
			    struct in6_addr **addr_p)
{
	struct rt0_hdr *phdr, *ihdr;
	int hops;

	ihdr = (struct rt0_hdr *) opt;
781

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	phdr = (struct rt0_hdr *) 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));

	ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
	*addr_p = ihdr->addr;

	phdr->rt_hdr.nexthdr = *proto;
	*proto = NEXTHDR_ROUTING;
}

static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
{
	struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)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)
{
811
	if (opt->srcrt) {
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		ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
813 814 815 816 817 818 819
		/*
		 * IPV6_RTHDRDSTOPTS is ignored
		 * unless IPV6_RTHDR is set (RFC3542).
		 */
		if (opt->dst0opt)
			ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
	}
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	if (opt->hopopt)
		ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
}

824 825
EXPORT_SYMBOL(ipv6_push_nfrag_opts);

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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);
}

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;
	}
	return opt2;
}
852

853 854
EXPORT_SYMBOL_GPL(ipv6_dup_options);

855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889
static int ipv6_renew_option(void *ohdr,
			     struct ipv6_opt_hdr __user *newopt, int newoptlen,
			     int inherit,
			     struct ipv6_opt_hdr **hdr,
			     char **p)
{
	if (inherit) {
		if (ohdr) {
			memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
			*hdr = (struct ipv6_opt_hdr *)*p;
			*p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
		}
	} else {
		if (newopt) {
			if (copy_from_user(*p, newopt, newoptlen))
				return -EFAULT;
			*hdr = (struct ipv6_opt_hdr *)*p;
			if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
				return -EINVAL;
			*p += CMSG_ALIGN(newoptlen);
		}
	}
	return 0;
}

struct ipv6_txoptions *
ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
		   int newtype,
		   struct ipv6_opt_hdr __user *newopt, int newoptlen)
{
	int tot_len = 0;
	char *p;
	struct ipv6_txoptions *opt2;
	int err;

890 891 892 893 894 895 896 897 898 899 900
	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));
	}

901 902 903 904 905 906
	if (newopt && newoptlen)
		tot_len += CMSG_ALIGN(newoptlen);

	if (!tot_len)
		return NULL;

907
	tot_len += sizeof(*opt2);
908 909 910 911 912 913 914 915 916
	opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
	if (!opt2)
		return ERR_PTR(-ENOBUFS);

	memset(opt2, 0, tot_len);

	opt2->tot_len = tot_len;
	p = (char *)(opt2 + 1);

917
	err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
918 919 920 921 922
				newtype != IPV6_HOPOPTS,
				&opt2->hopopt, &p);
	if (err)
		goto out;

923
	err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
924 925 926 927 928
				newtype != IPV6_RTHDRDSTOPTS,
				&opt2->dst0opt, &p);
	if (err)
		goto out;

929
	err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
930
				newtype != IPV6_RTHDR,
931
				(struct ipv6_opt_hdr **)&opt2->srcrt, &p);
932 933 934
	if (err)
		goto out;

935
	err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
936 937 938 939 940 941 942 943 944 945 946 947
				newtype != IPV6_DSTOPTS,
				&opt2->dst1opt, &p);
	if (err)
		goto out;

	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;
out:
948
	sock_kfree_s(sk, opt2, opt2->tot_len);
949 950 951
	return ERR_PTR(err);
}

952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
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 && 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;
}