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linux/net/ipv6/exthdrs.c
David Lebrun 013e816789 ipv6: sr: remove cleanup flag and fix HMAC computation 
In the latest version of the IPv6 Segment Routing IETF draft [1] the
cleanup flag is removed and the flags field length is shrunk from 16 bits
to 8 bits. As a consequence, the input of the HMAC computation is modified
in a non-backward compatible way by covering the whole octet of flags
instead of only the cleanup bit. As such, if an implementation compatible
with the latest draft computes the HMAC of an SRH who has other flags set
to 1, then the HMAC result would differ from the current implementation.

This patch carries those modifications to prevent conflict with other
implementations of IPv6 SR.

[1] https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-05

Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-03 11:05:23 -05:00

1183 lines
28 KiB
C
Raw Blame History

/*
* 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>
*
* 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:
* 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 <linux/uaccess.h>
/*
* Parsing tlv encoded headers.
*
* Parsing function "func" returns true, if parsing succeed
* and false, if it failed.
* It MUST NOT touch skb->h.
*/
struct tlvtype_proc {
int type;
bool (*func)(struct sk_buff *skb, int offset);
};
/*********************
Generic functions
*********************/
/* An unknown option is detected, decide what to do */
static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
{
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;
case 2: /* send ICMP PARM PROB regardless and drop packet */
icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
return false;
}
kfree_skb(skb);
return false;
}
/* Parse tlv encoded option header (hop-by-hop or destination) */
static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
{
const struct tlvtype_proc *curr;
const unsigned char *nh = skb_network_header(skb);
int off = skb_network_header_len(skb);
int len = (skb_transport_header(skb)[1] + 1) << 3;
int padlen = 0;
if (skb_transport_offset(skb) + len > skb_headlen(skb))
goto bad;
off += 2;
len -= 2;
while (len > 0) {
int optlen = nh[off + 1] + 2;
int i;
switch (nh[off]) {
case IPV6_TLV_PAD1:
optlen = 1;
padlen++;
if (padlen > 7)
goto bad;
break;
case 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;
}
break;
default: /* Other TLV code so scan list */
if (optlen > len)
goto bad;
for (curr = procs; curr->type >= 0; curr++) {
if (curr->type == nh[off]) {
/* type specific length/alignment
checks will be performed in the
func(). */
if (curr->func(skb, off) == false)
return false;
break;
}
}
if (curr->type < 0) {
if (ip6_tlvopt_unknown(skb, off) == 0)
return false;
}
padlen = 0;
break;
}
off += optlen;
len -= optlen;
}
if (len == 0)
return true;
bad:
kfree_skb(skb);
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);
struct in6_addr tmp_addr;
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);
goto discard;
}
if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
&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)) {
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;
tmp_addr = ipv6h->saddr;
ipv6h->saddr = hao->addr;
hao->addr = tmp_addr;
if (skb->tstamp == 0)
__net_timestamp(skb);
return true;
discard:
kfree_skb(skb);
return false;
}
#endif
static const struct tlvtype_proc tlvprocdestopt_lst[] = {
#if IS_ENABLED(CONFIG_IPV6_MIP6)
{
.type = IPV6_TLV_HAO,
.func = ipv6_dest_hao,
},
#endif
{-1, NULL}
};
static int ipv6_destopt_rcv(struct sk_buff *skb)
{
struct inet6_skb_parm *opt = IP6CB(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
__u16 dstbuf;
#endif
struct dst_entry *dst = skb_dst(skb);
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), ip6_dst_idev(dst),
IPSTATS_MIB_INHDRERRORS);
kfree_skb(skb);
return -1;
}
opt->lastopt = opt->dst1 = skb_network_header_len(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
dstbuf = opt->dst1;
#endif
if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
opt = IP6CB(skb);
#if IS_ENABLED(CONFIG_IPV6_MIP6)
opt->nhoff = dstbuf;
#else
opt->nhoff = opt->dst1;
#endif
return 1;
}
__IP6_INC_STATS(dev_net(dst->dev),
ip6_dst_idev(dst), 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) {
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 (hdr->segments_left >= (hdr->hdrlen >> 1)) {
__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
((&hdr->segments_left) -
skb_network_header(skb)));
kfree_skb(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, ip6_dst_idev(skb_dst(skb)),
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_skb_parm *opt = IP6CB(skb);
struct in6_addr *addr = NULL;
struct in6_addr daddr;
struct inet6_dev *idev;
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;
idev = __in6_dev_get(skb->dev);
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, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_INADDRERRORS);
kfree_skb(skb);
return -1;
}
/* segment routing */
if (hdr->type == IPV6_SRCRT_TYPE_4)
return ipv6_srh_rcv(skb);
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, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_INADDRERRORS);
kfree_skb(skb);
return -1;
}
if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
IPSTATS_MIB_INADDRERRORS);
kfree_skb(skb);
return -1;
}
break;
#endif
default:
break;
}
if (ipv6_addr_is_multicast(addr)) {
__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)),
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, ip6_dst_idev(skb_dst(skb)), 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 inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
{
return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
}
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(skb);
return false;
}
/* Jumbo payload */
static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
{
const unsigned char *nh = skb_network_header(skb);
struct net *net = ipv6_skb_net(skb);
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]);
__IP6_INC_STATS(net, ipv6_skb_idev(skb),
IPSTATS_MIB_INHDRERRORS);
goto drop;
}
pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
if (pkt_len <= IPV6_MAXPLEN) {
__IP6_INC_STATS(net, ipv6_skb_idev(skb),
IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
return false;
}
if (ipv6_hdr(skb)->payload_len) {
__IP6_INC_STATS(net, ipv6_skb_idev(skb),
IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
return false;
}
if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
__IP6_INC_STATS(net, ipv6_skb_idev(skb),
IPSTATS_MIB_INTRUNCATEDPKTS);
goto drop;
}
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
goto drop;
return true;
drop:
kfree_skb(skb);
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(skb);
return false;
}
static const struct tlvtype_proc tlvprochopopt_lst[] = {
{
.type = IPV6_TLV_ROUTERALERT,
.func = ipv6_hop_ra,
},
{
.type = IPV6_TLV_JUMBO,
.func = ipv6_hop_jumbo,
},
{
.type = IPV6_TLV_CALIPSO,
.func = ipv6_hop_calipso,
},
{ -1, }
};
int ipv6_parse_hopopts(struct sk_buff *skb)
{
struct inet6_skb_parm *opt = IP6CB(skb);
/*
* 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)))) {
kfree_skb(skb);
return -1;
}
opt->flags |= IP6SKB_HOPBYHOP;
if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
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 = (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));
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 = (struct ipv6_sr_hdr *)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[hops - 1];
#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:
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 = (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, 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);
}
EXPORT_SYMBOL(ipv6_push_nfrag_opts);
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;
atomic_set(&opt2->refcnt, 1);
}
return opt2;
}
EXPORT_SYMBOL_GPL(ipv6_dup_options);
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(*hdr));
}
} else {
if (newopt) {
if (copy_from_user(*p, newopt, newoptlen))
return -EFAULT;
*hdr = (struct ipv6_opt_hdr *)*p;
if (ipv6_optlen(*hdr) > newoptlen)
return -EINVAL;
*p += CMSG_ALIGN(newoptlen);
}
}
return 0;
}
/**
* 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)
* @newoptlen: length of @newopt
*
* 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 __user *newopt, int newoptlen)
{
int tot_len = 0;
char *p;
struct ipv6_txoptions *opt2;
int err;
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 && newoptlen)
tot_len += CMSG_ALIGN(newoptlen);
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);
atomic_set(&opt2->refcnt, 1);
opt2->tot_len = tot_len;
p = (char *)(opt2 + 1);
err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
newtype != IPV6_HOPOPTS,
&opt2->hopopt, &p);
if (err)
goto out;
err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
newtype != IPV6_RTHDRDSTOPTS,
&opt2->dst0opt, &p);
if (err)
goto out;
err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
newtype != IPV6_RTHDR,
(struct ipv6_opt_hdr **)&opt2->srcrt, &p);
if (err)
goto out;
err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
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:
sock_kfree_s(sk, opt2, opt2->tot_len);
return ERR_PTR(err);
}
/**
* ipv6_renew_options_kern - 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 (kernel-mem)
* @newoptlen: length of @newopt
*
* See ipv6_renew_options(). The difference is that @newopt is
* kernel memory, rather than user memory.
*/
struct ipv6_txoptions *
ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt,
int newtype, struct ipv6_opt_hdr *newopt,
int newoptlen)
{
struct ipv6_txoptions *ret_val;
const mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
ret_val = ipv6_renew_options(sk, opt, newtype,
(struct ipv6_opt_hdr __user *)newopt,
newoptlen);
set_fs(old_fs);
return ret_val;
}
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;
}
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:
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->first_segment];
break;
}
default:
return NULL;
}
return orig;
}
EXPORT_SYMBOL_GPL(fl6_update_dst);
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