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-rw-r--r--net/ipv6/ip6_input.c593
1 files changed, 593 insertions, 0 deletions
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
new file mode 100644
index 000000000..b83788145
--- /dev/null
+++ b/net/ipv6/ip6_input.c
@@ -0,0 +1,593 @@
+// 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/udp.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>
+
+static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
+{
+ if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&
+ !skb_dst(skb) && !skb->sk) {
+ switch (ipv6_hdr(skb)->nexthdr) {
+ case IPPROTO_TCP:
+ if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux))
+ tcp_v6_early_demux(skb);
+ break;
+ case IPPROTO_UDP:
+ if (READ_ONCE(net->ipv4.sysctl_udp_early_demux))
+ udp_v6_early_demux(skb);
+ break;
+ }
+ }
+
+ 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) ||
+ IP6CB(skb)->flags & IP6SKB_MULTIPATH)
+ 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)
+{
+ enum skb_drop_reason reason;
+ const struct ipv6hdr *hdr;
+ u32 pkt_len;
+ struct inet6_dev *idev;
+
+ if (skb->pkt_type == PACKET_OTHERHOST) {
+ dev_core_stats_rx_otherhost_dropped_inc(skb->dev);
+ kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST);
+ return NULL;
+ }
+
+ rcu_read_lock();
+
+ idev = __in6_dev_get(skb->dev);
+
+ __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
+
+ SKB_DR_SET(reason, NOT_SPECIFIED);
+ if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
+ !idev || unlikely(idev->cnf.disable_ipv6)) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
+ if (idev && unlikely(idev->cnf.disable_ipv6))
+ SKB_DR_SET(reason, IPV6DISABLED);
+ 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) {
+ SKB_DR_SET(reason, UNHANDLED_PROTO);
+ 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) {
+ SKB_DR_SET(reason, 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;
+
+ 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);
+ SKB_DR_SET(reason, PKT_TOO_SMALL);
+ goto drop;
+ }
+ if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
+ goto err;
+ 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. */
+ if (!skb_sk_is_prefetched(skb))
+ skb_orphan(skb);
+
+ return skb;
+err:
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ SKB_DR_OR(reason, IP_INHDR);
+drop:
+ rcu_read_unlock();
+ kfree_skb_reason(skb, reason);
+ 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 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;
+ SKB_DR(reason);
+ 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;
+
+
+ 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))) {
+ SKB_DR_SET(reason, IP_INADDRERRORS);
+ goto discard;
+ }
+ }
+ if (!(ipprot->flags & INET6_PROTO_NOPOLICY)) {
+ if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+ SKB_DR_SET(reason, XFRM_POLICY);
+ goto discard;
+ }
+ nf_reset_ct(skb);
+ }
+
+ 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);
+ SKB_DR_SET(reason, IP_NOPROTO);
+ } else {
+ SKB_DR_SET(reason, XFRM_POLICY);
+ }
+ kfree_skb_reason(skb, reason);
+ } else {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
+ consume_skb(skb);
+ }
+ }
+ return;
+
+discard:
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
+ kfree_skb_reason(skb, reason);
+}
+
+static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ skb_clear_delivery_time(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 (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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-09 07:58:55 +0000