574 lines
14 KiB
C
574 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* IPv6 input
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* Linux INET6 implementation
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*
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* Authors:
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* Pedro Roque <roque@di.fc.ul.pt>
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* Ian P. Morris <I.P.Morris@soton.ac.uk>
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*
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* Based in linux/net/ipv4/ip_input.c
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*/
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/* Changes
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*
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* Mitsuru KANDA @USAGI and
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* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <linux/netdevice.h>
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#include <linux/in6.h>
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#include <linux/icmpv6.h>
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#include <linux/mroute6.h>
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#include <linux/slab.h>
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#include <linux/indirect_call_wrapper.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/sock.h>
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#include <net/snmp.h>
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#include <net/udp.h>
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#include <net/ipv6.h>
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#include <net/protocol.h>
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#include <net/transp_v6.h>
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#include <net/rawv6.h>
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#include <net/ndisc.h>
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#include <net/ip6_route.h>
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#include <net/addrconf.h>
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#include <net/xfrm.h>
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#include <net/inet_ecn.h>
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#include <net/dst_metadata.h>
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INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *));
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static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
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struct sk_buff *skb)
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{
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void (*edemux)(struct sk_buff *skb);
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if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
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const struct inet6_protocol *ipprot;
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ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
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if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
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INDIRECT_CALL_2(edemux, tcp_v6_early_demux,
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udp_v6_early_demux, skb);
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}
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if (!skb_valid_dst(skb))
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ip6_route_input(skb);
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}
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int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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/* if ingress device is enslaved to an L3 master device pass the
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* skb to its handler for processing
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*/
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skb = l3mdev_ip6_rcv(skb);
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if (!skb)
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return NET_RX_SUCCESS;
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ip6_rcv_finish_core(net, sk, skb);
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return dst_input(skb);
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}
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static void ip6_sublist_rcv_finish(struct list_head *head)
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{
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struct sk_buff *skb, *next;
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list_for_each_entry_safe(skb, next, head, list) {
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skb_list_del_init(skb);
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dst_input(skb);
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}
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}
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static bool ip6_can_use_hint(const struct sk_buff *skb,
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const struct sk_buff *hint)
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{
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return hint && !skb_dst(skb) &&
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ipv6_addr_equal(&ipv6_hdr(hint)->daddr, &ipv6_hdr(skb)->daddr);
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}
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static struct sk_buff *ip6_extract_route_hint(const struct net *net,
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struct sk_buff *skb)
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{
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if (fib6_routes_require_src(net) || fib6_has_custom_rules(net))
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return NULL;
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return skb;
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}
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static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
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struct list_head *head)
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{
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struct sk_buff *skb, *next, *hint = NULL;
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struct dst_entry *curr_dst = NULL;
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struct list_head sublist;
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INIT_LIST_HEAD(&sublist);
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list_for_each_entry_safe(skb, next, head, list) {
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struct dst_entry *dst;
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skb_list_del_init(skb);
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/* if ingress device is enslaved to an L3 master device pass the
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* skb to its handler for processing
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*/
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skb = l3mdev_ip6_rcv(skb);
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if (!skb)
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continue;
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if (ip6_can_use_hint(skb, hint))
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skb_dst_copy(skb, hint);
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else
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ip6_rcv_finish_core(net, sk, skb);
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dst = skb_dst(skb);
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if (curr_dst != dst) {
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hint = ip6_extract_route_hint(net, skb);
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/* dispatch old sublist */
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if (!list_empty(&sublist))
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ip6_sublist_rcv_finish(&sublist);
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/* start new sublist */
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INIT_LIST_HEAD(&sublist);
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curr_dst = dst;
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}
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list_add_tail(&skb->list, &sublist);
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}
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/* dispatch final sublist */
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ip6_sublist_rcv_finish(&sublist);
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}
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static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
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struct net *net)
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{
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const struct ipv6hdr *hdr;
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u32 pkt_len;
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struct inet6_dev *idev;
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if (skb->pkt_type == PACKET_OTHERHOST) {
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kfree_skb(skb);
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return NULL;
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}
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rcu_read_lock();
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idev = __in6_dev_get(skb->dev);
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__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
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if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
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!idev || unlikely(idev->cnf.disable_ipv6)) {
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
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goto drop;
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}
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memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
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/*
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* Store incoming device index. When the packet will
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* be queued, we cannot refer to skb->dev anymore.
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*
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* BTW, when we send a packet for our own local address on a
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* non-loopback interface (e.g. ethX), it is being delivered
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* via the loopback interface (lo) here; skb->dev = loopback_dev.
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* It, however, should be considered as if it is being
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* arrived via the sending interface (ethX), because of the
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* nature of scoping architecture. --yoshfuji
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*/
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IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
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if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
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goto err;
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hdr = ipv6_hdr(skb);
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if (hdr->version != 6)
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goto err;
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__IP6_ADD_STATS(net, idev,
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IPSTATS_MIB_NOECTPKTS +
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(ipv6_get_dsfield(hdr) & INET_ECN_MASK),
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max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
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/*
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* RFC4291 2.5.3
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* The loopback address must not be used as the source address in IPv6
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* packets that are sent outside of a single node. [..]
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* A packet received on an interface with a destination address
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* of loopback must be dropped.
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*/
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if ((ipv6_addr_loopback(&hdr->saddr) ||
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ipv6_addr_loopback(&hdr->daddr)) &&
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!(dev->flags & IFF_LOOPBACK) &&
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!netif_is_l3_master(dev))
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goto err;
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/* RFC4291 Errata ID: 3480
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* Interface-Local scope spans only a single interface on a
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* node and is useful only for loopback transmission of
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* multicast. Packets with interface-local scope received
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* from another node must be discarded.
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*/
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if (!(skb->pkt_type == PACKET_LOOPBACK ||
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dev->flags & IFF_LOOPBACK) &&
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ipv6_addr_is_multicast(&hdr->daddr) &&
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IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
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goto err;
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/* If enabled, drop unicast packets that were encapsulated in link-layer
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* multicast or broadcast to protected against the so-called "hole-196"
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* attack in 802.11 wireless.
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*/
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if (!ipv6_addr_is_multicast(&hdr->daddr) &&
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(skb->pkt_type == PACKET_BROADCAST ||
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skb->pkt_type == PACKET_MULTICAST) &&
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idev->cnf.drop_unicast_in_l2_multicast)
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goto err;
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/* RFC4291 2.7
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* Nodes must not originate a packet to a multicast address whose scope
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* field contains the reserved value 0; if such a packet is received, it
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* must be silently dropped.
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*/
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if (ipv6_addr_is_multicast(&hdr->daddr) &&
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IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
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goto err;
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/*
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* RFC4291 2.7
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* Multicast addresses must not be used as source addresses in IPv6
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* packets or appear in any Routing header.
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*/
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if (ipv6_addr_is_multicast(&hdr->saddr))
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goto err;
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skb->transport_header = skb->network_header + sizeof(*hdr);
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IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
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pkt_len = ntohs(hdr->payload_len);
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/* pkt_len may be zero if Jumbo payload option is present */
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if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
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if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
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__IP6_INC_STATS(net,
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idev, IPSTATS_MIB_INTRUNCATEDPKTS);
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goto drop;
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}
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if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
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goto drop;
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}
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hdr = ipv6_hdr(skb);
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}
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if (hdr->nexthdr == NEXTHDR_HOP) {
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if (ipv6_parse_hopopts(skb) < 0) {
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
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rcu_read_unlock();
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return NULL;
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}
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}
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rcu_read_unlock();
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/* Must drop socket now because of tproxy. */
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if (!skb_sk_is_prefetched(skb))
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skb_orphan(skb);
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return skb;
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err:
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
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drop:
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rcu_read_unlock();
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kfree_skb(skb);
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return NULL;
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}
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int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
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{
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struct net *net = dev_net(skb->dev);
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skb = ip6_rcv_core(skb, dev, net);
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if (skb == NULL)
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return NET_RX_DROP;
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return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
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net, NULL, skb, dev, NULL,
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ip6_rcv_finish);
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}
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static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
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struct net *net)
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{
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NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
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head, dev, NULL, ip6_rcv_finish);
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ip6_list_rcv_finish(net, NULL, head);
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}
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/* Receive a list of IPv6 packets */
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void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
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struct net_device *orig_dev)
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{
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struct net_device *curr_dev = NULL;
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struct net *curr_net = NULL;
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struct sk_buff *skb, *next;
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struct list_head sublist;
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INIT_LIST_HEAD(&sublist);
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list_for_each_entry_safe(skb, next, head, list) {
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struct net_device *dev = skb->dev;
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struct net *net = dev_net(dev);
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skb_list_del_init(skb);
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skb = ip6_rcv_core(skb, dev, net);
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if (skb == NULL)
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continue;
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if (curr_dev != dev || curr_net != net) {
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/* dispatch old sublist */
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if (!list_empty(&sublist))
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ip6_sublist_rcv(&sublist, curr_dev, curr_net);
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/* start new sublist */
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INIT_LIST_HEAD(&sublist);
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curr_dev = dev;
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curr_net = net;
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}
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list_add_tail(&skb->list, &sublist);
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}
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/* dispatch final sublist */
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if (!list_empty(&sublist))
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ip6_sublist_rcv(&sublist, curr_dev, curr_net);
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}
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INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *));
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/*
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* Deliver the packet to the host
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*/
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void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
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bool have_final)
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{
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const struct inet6_protocol *ipprot;
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struct inet6_dev *idev;
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unsigned int nhoff;
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bool raw;
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/*
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* Parse extension headers
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*/
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resubmit:
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idev = ip6_dst_idev(skb_dst(skb));
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nhoff = IP6CB(skb)->nhoff;
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if (!have_final) {
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if (!pskb_pull(skb, skb_transport_offset(skb)))
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goto discard;
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nexthdr = skb_network_header(skb)[nhoff];
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}
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resubmit_final:
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raw = raw6_local_deliver(skb, nexthdr);
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ipprot = rcu_dereference(inet6_protos[nexthdr]);
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if (ipprot) {
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int ret;
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if (have_final) {
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if (!(ipprot->flags & INET6_PROTO_FINAL)) {
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/* Once we've seen a final protocol don't
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* allow encapsulation on any non-final
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* ones. This allows foo in UDP encapsulation
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* to work.
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*/
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goto discard;
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}
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} else if (ipprot->flags & INET6_PROTO_FINAL) {
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const struct ipv6hdr *hdr;
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int sdif = inet6_sdif(skb);
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struct net_device *dev;
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/* Only do this once for first final protocol */
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have_final = true;
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/* Free reference early: we don't need it any more,
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and it may hold ip_conntrack module loaded
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indefinitely. */
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nf_reset_ct(skb);
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skb_postpull_rcsum(skb, skb_network_header(skb),
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skb_network_header_len(skb));
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hdr = ipv6_hdr(skb);
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/* skb->dev passed may be master dev for vrfs. */
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if (sdif) {
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dev = dev_get_by_index_rcu(net, sdif);
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if (!dev)
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goto discard;
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} else {
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dev = skb->dev;
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}
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if (ipv6_addr_is_multicast(&hdr->daddr) &&
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!ipv6_chk_mcast_addr(dev, &hdr->daddr,
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&hdr->saddr) &&
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!ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
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goto discard;
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}
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if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
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!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
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goto discard;
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ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv,
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skb);
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if (ret > 0) {
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if (ipprot->flags & INET6_PROTO_FINAL) {
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/* Not an extension header, most likely UDP
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* encapsulation. Use return value as nexthdr
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* protocol not nhoff (which presumably is
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* not set by handler).
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*/
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nexthdr = ret;
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goto resubmit_final;
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} else {
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goto resubmit;
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}
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} else if (ret == 0) {
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
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}
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} else {
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if (!raw) {
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if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
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__IP6_INC_STATS(net, idev,
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IPSTATS_MIB_INUNKNOWNPROTOS);
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icmpv6_send(skb, ICMPV6_PARAMPROB,
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ICMPV6_UNK_NEXTHDR, nhoff);
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}
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kfree_skb(skb);
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} else {
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
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consume_skb(skb);
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}
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}
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return;
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discard:
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__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
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kfree_skb(skb);
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}
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static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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rcu_read_lock();
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ip6_protocol_deliver_rcu(net, skb, 0, false);
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rcu_read_unlock();
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return 0;
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}
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int ip6_input(struct sk_buff *skb)
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{
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return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
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dev_net(skb->dev), NULL, skb, skb->dev, NULL,
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ip6_input_finish);
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}
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EXPORT_SYMBOL_GPL(ip6_input);
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int ip6_mc_input(struct sk_buff *skb)
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{
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int sdif = inet6_sdif(skb);
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const struct ipv6hdr *hdr;
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struct net_device *dev;
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bool deliver;
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__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
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__in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
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skb->len);
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/* 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 (atomic_read(&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;
|
|
}
|