584 lines
14 KiB
C
584 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* IPv6 input
|
|
* Linux INET6 implementation
|
|
*
|
|
* Authors:
|
|
* Pedro Roque <roque@di.fc.ul.pt>
|
|
* Ian P. Morris <I.P.Morris@soton.ac.uk>
|
|
*
|
|
* Based in linux/net/ipv4/ip_input.c
|
|
*/
|
|
/* Changes
|
|
*
|
|
* Mitsuru KANDA @USAGI and
|
|
* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
|
|
*/
|
|
|
|
#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/mroute6.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/indirect_call_wrapper.h>
|
|
|
|
#include <linux/netfilter.h>
|
|
#include <linux/netfilter_ipv6.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/xfrm.h>
|
|
#include <net/inet_ecn.h>
|
|
#include <net/dst_metadata.h>
|
|
|
|
INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *));
|
|
INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *));
|
|
static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
|
|
struct sk_buff *skb)
|
|
{
|
|
void (*edemux)(struct sk_buff *skb);
|
|
|
|
if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
|
|
const struct inet6_protocol *ipprot;
|
|
|
|
ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
|
|
if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
|
|
INDIRECT_CALL_2(edemux, tcp_v6_early_demux,
|
|
udp_v6_early_demux, skb);
|
|
}
|
|
if (!skb_valid_dst(skb))
|
|
ip6_route_input(skb);
|
|
}
|
|
|
|
int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
/* if ingress device is enslaved to an L3 master device pass the
|
|
* skb to its handler for processing
|
|
*/
|
|
skb = l3mdev_ip6_rcv(skb);
|
|
if (!skb)
|
|
return NET_RX_SUCCESS;
|
|
ip6_rcv_finish_core(net, sk, skb);
|
|
|
|
return dst_input(skb);
|
|
}
|
|
|
|
static void ip6_sublist_rcv_finish(struct list_head *head)
|
|
{
|
|
struct sk_buff *skb, *next;
|
|
|
|
list_for_each_entry_safe(skb, next, head, list) {
|
|
skb_list_del_init(skb);
|
|
dst_input(skb);
|
|
}
|
|
}
|
|
|
|
static bool ip6_can_use_hint(const struct sk_buff *skb,
|
|
const struct sk_buff *hint)
|
|
{
|
|
return hint && !skb_dst(skb) &&
|
|
ipv6_addr_equal(&ipv6_hdr(hint)->daddr, &ipv6_hdr(skb)->daddr);
|
|
}
|
|
|
|
static struct sk_buff *ip6_extract_route_hint(const struct net *net,
|
|
struct sk_buff *skb)
|
|
{
|
|
if (fib6_routes_require_src(net) || fib6_has_custom_rules(net))
|
|
return NULL;
|
|
|
|
return skb;
|
|
}
|
|
|
|
static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
|
|
struct list_head *head)
|
|
{
|
|
struct sk_buff *skb, *next, *hint = NULL;
|
|
struct dst_entry *curr_dst = NULL;
|
|
struct list_head sublist;
|
|
|
|
INIT_LIST_HEAD(&sublist);
|
|
list_for_each_entry_safe(skb, next, head, list) {
|
|
struct dst_entry *dst;
|
|
|
|
skb_list_del_init(skb);
|
|
/* if ingress device is enslaved to an L3 master device pass the
|
|
* skb to its handler for processing
|
|
*/
|
|
skb = l3mdev_ip6_rcv(skb);
|
|
if (!skb)
|
|
continue;
|
|
|
|
if (ip6_can_use_hint(skb, hint))
|
|
skb_dst_copy(skb, hint);
|
|
else
|
|
ip6_rcv_finish_core(net, sk, skb);
|
|
dst = skb_dst(skb);
|
|
if (curr_dst != dst) {
|
|
hint = ip6_extract_route_hint(net, skb);
|
|
|
|
/* dispatch old sublist */
|
|
if (!list_empty(&sublist))
|
|
ip6_sublist_rcv_finish(&sublist);
|
|
/* start new sublist */
|
|
INIT_LIST_HEAD(&sublist);
|
|
curr_dst = dst;
|
|
}
|
|
list_add_tail(&skb->list, &sublist);
|
|
}
|
|
/* dispatch final sublist */
|
|
ip6_sublist_rcv_finish(&sublist);
|
|
}
|
|
|
|
static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
|
|
struct net *net)
|
|
{
|
|
const struct ipv6hdr *hdr;
|
|
u32 pkt_len;
|
|
struct inet6_dev *idev;
|
|
|
|
if (skb->pkt_type == PACKET_OTHERHOST) {
|
|
kfree_skb(skb);
|
|
return NULL;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
|
|
idev = __in6_dev_get(skb->dev);
|
|
|
|
__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
|
|
|
|
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
|
|
!idev || unlikely(idev->cnf.disable_ipv6)) {
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
|
|
goto drop;
|
|
}
|
|
|
|
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
|
|
|
|
/*
|
|
* Store incoming device index. When the packet will
|
|
* be queued, we cannot refer to skb->dev anymore.
|
|
*
|
|
* BTW, when we send a packet for our own local address on a
|
|
* non-loopback interface (e.g. ethX), it is being delivered
|
|
* via the loopback interface (lo) here; skb->dev = loopback_dev.
|
|
* It, however, should be considered as if it is being
|
|
* arrived via the sending interface (ethX), because of the
|
|
* nature of scoping architecture. --yoshfuji
|
|
*/
|
|
IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
|
|
|
|
if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
|
|
goto err;
|
|
|
|
hdr = ipv6_hdr(skb);
|
|
|
|
if (hdr->version != 6)
|
|
goto err;
|
|
|
|
__IP6_ADD_STATS(net, idev,
|
|
IPSTATS_MIB_NOECTPKTS +
|
|
(ipv6_get_dsfield(hdr) & INET_ECN_MASK),
|
|
max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
|
|
/*
|
|
* RFC4291 2.5.3
|
|
* The loopback address must not be used as the source address in IPv6
|
|
* packets that are sent outside of a single node. [..]
|
|
* A packet received on an interface with a destination address
|
|
* of loopback must be dropped.
|
|
*/
|
|
if ((ipv6_addr_loopback(&hdr->saddr) ||
|
|
ipv6_addr_loopback(&hdr->daddr)) &&
|
|
!(dev->flags & IFF_LOOPBACK) &&
|
|
!netif_is_l3_master(dev))
|
|
goto err;
|
|
|
|
/* RFC4291 Errata ID: 3480
|
|
* Interface-Local scope spans only a single interface on a
|
|
* node and is useful only for loopback transmission of
|
|
* multicast. Packets with interface-local scope received
|
|
* from another node must be discarded.
|
|
*/
|
|
if (!(skb->pkt_type == PACKET_LOOPBACK ||
|
|
dev->flags & IFF_LOOPBACK) &&
|
|
ipv6_addr_is_multicast(&hdr->daddr) &&
|
|
IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
|
|
goto err;
|
|
|
|
/* If enabled, drop unicast packets that were encapsulated in link-layer
|
|
* multicast or broadcast to protected against the so-called "hole-196"
|
|
* attack in 802.11 wireless.
|
|
*/
|
|
if (!ipv6_addr_is_multicast(&hdr->daddr) &&
|
|
(skb->pkt_type == PACKET_BROADCAST ||
|
|
skb->pkt_type == PACKET_MULTICAST) &&
|
|
idev->cnf.drop_unicast_in_l2_multicast)
|
|
goto err;
|
|
|
|
/* RFC4291 2.7
|
|
* Nodes must not originate a packet to a multicast address whose scope
|
|
* field contains the reserved value 0; if such a packet is received, it
|
|
* must be silently dropped.
|
|
*/
|
|
if (ipv6_addr_is_multicast(&hdr->daddr) &&
|
|
IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
|
|
goto err;
|
|
|
|
/*
|
|
* RFC4291 2.7
|
|
* Multicast addresses must not be used as source addresses in IPv6
|
|
* packets or appear in any Routing header.
|
|
*/
|
|
if (ipv6_addr_is_multicast(&hdr->saddr))
|
|
goto err;
|
|
|
|
/* While RFC4291 is not explicit about v4mapped addresses
|
|
* in IPv6 headers, it seems clear linux dual-stack
|
|
* model can not deal properly with these.
|
|
* Security models could be fooled by ::ffff:127.0.0.1 for example.
|
|
*
|
|
* https://tools.ietf.org/html/draft-itojun-v6ops-v4mapped-harmful-02
|
|
*/
|
|
if (ipv6_addr_v4mapped(&hdr->saddr))
|
|
goto err;
|
|
|
|
skb->transport_header = skb->network_header + sizeof(*hdr);
|
|
IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
|
|
|
|
pkt_len = ntohs(hdr->payload_len);
|
|
|
|
/* pkt_len may be zero if Jumbo payload option is present */
|
|
if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
|
|
if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
|
|
__IP6_INC_STATS(net,
|
|
idev, IPSTATS_MIB_INTRUNCATEDPKTS);
|
|
goto drop;
|
|
}
|
|
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
|
|
goto drop;
|
|
}
|
|
hdr = ipv6_hdr(skb);
|
|
}
|
|
|
|
if (hdr->nexthdr == NEXTHDR_HOP) {
|
|
if (ipv6_parse_hopopts(skb) < 0) {
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
|
|
rcu_read_unlock();
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
/* Must drop socket now because of tproxy. */
|
|
skb_orphan(skb);
|
|
|
|
return skb;
|
|
err:
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
|
|
drop:
|
|
rcu_read_unlock();
|
|
kfree_skb(skb);
|
|
return NULL;
|
|
}
|
|
|
|
int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
|
|
{
|
|
struct net *net = dev_net(skb->dev);
|
|
|
|
skb = ip6_rcv_core(skb, dev, net);
|
|
if (skb == NULL)
|
|
return NET_RX_DROP;
|
|
return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
|
|
net, NULL, skb, dev, NULL,
|
|
ip6_rcv_finish);
|
|
}
|
|
|
|
static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
|
|
struct net *net)
|
|
{
|
|
NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
|
|
head, dev, NULL, ip6_rcv_finish);
|
|
ip6_list_rcv_finish(net, NULL, head);
|
|
}
|
|
|
|
/* Receive a list of IPv6 packets */
|
|
void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
|
|
struct net_device *orig_dev)
|
|
{
|
|
struct net_device *curr_dev = NULL;
|
|
struct net *curr_net = NULL;
|
|
struct sk_buff *skb, *next;
|
|
struct list_head sublist;
|
|
|
|
INIT_LIST_HEAD(&sublist);
|
|
list_for_each_entry_safe(skb, next, head, list) {
|
|
struct net_device *dev = skb->dev;
|
|
struct net *net = dev_net(dev);
|
|
|
|
skb_list_del_init(skb);
|
|
skb = ip6_rcv_core(skb, dev, net);
|
|
if (skb == NULL)
|
|
continue;
|
|
|
|
if (curr_dev != dev || curr_net != net) {
|
|
/* dispatch old sublist */
|
|
if (!list_empty(&sublist))
|
|
ip6_sublist_rcv(&sublist, curr_dev, curr_net);
|
|
/* start new sublist */
|
|
INIT_LIST_HEAD(&sublist);
|
|
curr_dev = dev;
|
|
curr_net = net;
|
|
}
|
|
list_add_tail(&skb->list, &sublist);
|
|
}
|
|
/* dispatch final sublist */
|
|
if (!list_empty(&sublist))
|
|
ip6_sublist_rcv(&sublist, curr_dev, curr_net);
|
|
}
|
|
|
|
INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
|
|
INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *));
|
|
|
|
/*
|
|
* Deliver the packet to the host
|
|
*/
|
|
void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
|
|
bool have_final)
|
|
{
|
|
const struct inet6_protocol *ipprot;
|
|
struct inet6_dev *idev;
|
|
unsigned int nhoff;
|
|
bool raw;
|
|
|
|
/*
|
|
* Parse extension headers
|
|
*/
|
|
|
|
resubmit:
|
|
idev = ip6_dst_idev(skb_dst(skb));
|
|
nhoff = IP6CB(skb)->nhoff;
|
|
if (!have_final) {
|
|
if (!pskb_pull(skb, skb_transport_offset(skb)))
|
|
goto discard;
|
|
nexthdr = skb_network_header(skb)[nhoff];
|
|
}
|
|
|
|
resubmit_final:
|
|
raw = raw6_local_deliver(skb, nexthdr);
|
|
ipprot = rcu_dereference(inet6_protos[nexthdr]);
|
|
if (ipprot) {
|
|
int ret;
|
|
|
|
if (have_final) {
|
|
if (!(ipprot->flags & INET6_PROTO_FINAL)) {
|
|
/* Once we've seen a final protocol don't
|
|
* allow encapsulation on any non-final
|
|
* ones. This allows foo in UDP encapsulation
|
|
* to work.
|
|
*/
|
|
goto discard;
|
|
}
|
|
} else if (ipprot->flags & INET6_PROTO_FINAL) {
|
|
const struct ipv6hdr *hdr;
|
|
int sdif = inet6_sdif(skb);
|
|
struct net_device *dev;
|
|
|
|
/* Only do this once for first final protocol */
|
|
have_final = true;
|
|
|
|
/* Free reference early: we don't need it any more,
|
|
and it may hold ip_conntrack module loaded
|
|
indefinitely. */
|
|
nf_reset_ct(skb);
|
|
|
|
skb_postpull_rcsum(skb, skb_network_header(skb),
|
|
skb_network_header_len(skb));
|
|
hdr = ipv6_hdr(skb);
|
|
|
|
/* skb->dev passed may be master dev for vrfs. */
|
|
if (sdif) {
|
|
dev = dev_get_by_index_rcu(net, sdif);
|
|
if (!dev)
|
|
goto discard;
|
|
} else {
|
|
dev = skb->dev;
|
|
}
|
|
|
|
if (ipv6_addr_is_multicast(&hdr->daddr) &&
|
|
!ipv6_chk_mcast_addr(dev, &hdr->daddr,
|
|
&hdr->saddr) &&
|
|
!ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
|
|
goto discard;
|
|
}
|
|
if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
|
|
!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
|
|
goto discard;
|
|
|
|
ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv,
|
|
skb);
|
|
if (ret > 0) {
|
|
if (ipprot->flags & INET6_PROTO_FINAL) {
|
|
/* Not an extension header, most likely UDP
|
|
* encapsulation. Use return value as nexthdr
|
|
* protocol not nhoff (which presumably is
|
|
* not set by handler).
|
|
*/
|
|
nexthdr = ret;
|
|
goto resubmit_final;
|
|
} else {
|
|
goto resubmit;
|
|
}
|
|
} else if (ret == 0) {
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
|
|
}
|
|
} else {
|
|
if (!raw) {
|
|
if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
|
|
__IP6_INC_STATS(net, idev,
|
|
IPSTATS_MIB_INUNKNOWNPROTOS);
|
|
icmpv6_send(skb, ICMPV6_PARAMPROB,
|
|
ICMPV6_UNK_NEXTHDR, nhoff);
|
|
}
|
|
kfree_skb(skb);
|
|
} else {
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
|
|
consume_skb(skb);
|
|
}
|
|
}
|
|
return;
|
|
|
|
discard:
|
|
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
rcu_read_lock();
|
|
ip6_protocol_deliver_rcu(net, skb, 0, false);
|
|
rcu_read_unlock();
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
int ip6_input(struct sk_buff *skb)
|
|
{
|
|
return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
|
|
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
|
|
ip6_input_finish);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ip6_input);
|
|
|
|
int ip6_mc_input(struct sk_buff *skb)
|
|
{
|
|
int sdif = inet6_sdif(skb);
|
|
const struct ipv6hdr *hdr;
|
|
struct net_device *dev;
|
|
bool deliver;
|
|
|
|
__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
|
|
__in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
|
|
skb->len);
|
|
|
|
/* skb->dev passed may be master dev for vrfs. */
|
|
if (sdif) {
|
|
rcu_read_lock();
|
|
dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);
|
|
if (!dev) {
|
|
rcu_read_unlock();
|
|
kfree_skb(skb);
|
|
return -ENODEV;
|
|
}
|
|
} else {
|
|
dev = skb->dev;
|
|
}
|
|
|
|
hdr = ipv6_hdr(skb);
|
|
deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);
|
|
if (sdif)
|
|
rcu_read_unlock();
|
|
|
|
#ifdef CONFIG_IPV6_MROUTE
|
|
/*
|
|
* IPv6 multicast router mode is now supported ;)
|
|
*/
|
|
if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
|
|
!(ipv6_addr_type(&hdr->daddr) &
|
|
(IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
|
|
likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
|
|
/*
|
|
* Okay, we try to forward - split and duplicate
|
|
* packets.
|
|
*/
|
|
struct sk_buff *skb2;
|
|
struct inet6_skb_parm *opt = IP6CB(skb);
|
|
|
|
/* Check for MLD */
|
|
if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
|
|
/* Check if this is a mld message */
|
|
u8 nexthdr = hdr->nexthdr;
|
|
__be16 frag_off;
|
|
int offset;
|
|
|
|
/* Check if the value of Router Alert
|
|
* is for MLD (0x0000).
|
|
*/
|
|
if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
|
|
deliver = false;
|
|
|
|
if (!ipv6_ext_hdr(nexthdr)) {
|
|
/* BUG */
|
|
goto out;
|
|
}
|
|
offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
|
|
&nexthdr, &frag_off);
|
|
if (offset < 0)
|
|
goto out;
|
|
|
|
if (ipv6_is_mld(skb, nexthdr, offset))
|
|
deliver = true;
|
|
|
|
goto out;
|
|
}
|
|
/* unknown RA - process it normally */
|
|
}
|
|
|
|
if (deliver)
|
|
skb2 = skb_clone(skb, GFP_ATOMIC);
|
|
else {
|
|
skb2 = skb;
|
|
skb = NULL;
|
|
}
|
|
|
|
if (skb2) {
|
|
ip6_mr_input(skb2);
|
|
}
|
|
}
|
|
out:
|
|
#endif
|
|
if (likely(deliver))
|
|
ip6_input(skb);
|
|
else {
|
|
/* discard */
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
return 0;
|
|
}
|