| /* |
| * 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 |
| * |
| * 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 |
| * |
| * 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/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> |
| |
| int ip6_rcv_finish(struct sock *sk, struct sk_buff *skb) |
| { |
| if (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 && ipprot->early_demux) |
| ipprot->early_demux(skb); |
| } |
| if (!skb_dst(skb)) |
| ip6_route_input(skb); |
| |
| return dst_input(skb); |
| } |
| |
| int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) |
| { |
| const struct ipv6hdr *hdr; |
| u32 pkt_len; |
| struct inet6_dev *idev; |
| struct net *net = dev_net(skb->dev); |
| |
| if (skb->pkt_type == PACKET_OTHERHOST) { |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| rcu_read_lock(); |
| |
| idev = __in6_dev_get(skb->dev); |
| |
| IP6_UPD_PO_STATS_BH(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_BH(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_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_BH(dev_net(dev), 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 |
| * A packet received on an interface with a destination address |
| * of loopback must be dropped. |
| */ |
| if (!(dev->flags & IFF_LOOPBACK) && |
| ipv6_addr_loopback(&hdr->daddr)) |
| 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; |
| |
| /* 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_BH(net, |
| idev, IPSTATS_MIB_INTRUNCATEDPKTS); |
| goto drop; |
| } |
| if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { |
| IP6_INC_STATS_BH(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_BH(net, idev, IPSTATS_MIB_INHDRERRORS); |
| rcu_read_unlock(); |
| return NET_RX_DROP; |
| } |
| } |
| |
| rcu_read_unlock(); |
| |
| /* Must drop socket now because of tproxy. */ |
| skb_orphan(skb); |
| |
| return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, NULL, skb, |
| dev, NULL, |
| ip6_rcv_finish); |
| err: |
| IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); |
| drop: |
| rcu_read_unlock(); |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| /* |
| * Deliver the packet to the host |
| */ |
| |
| |
| static int ip6_input_finish(struct sock *sk, struct sk_buff *skb) |
| { |
| struct net *net = dev_net(skb_dst(skb)->dev); |
| const struct inet6_protocol *ipprot; |
| struct inet6_dev *idev; |
| unsigned int nhoff; |
| int nexthdr; |
| bool raw; |
| |
| /* |
| * Parse extension headers |
| */ |
| |
| rcu_read_lock(); |
| idev = ip6_dst_idev(skb_dst(skb)); |
| if (!pskb_pull(skb, skb_transport_offset(skb))) |
| goto discard; |
| nhoff = IP6CB(skb)->nhoff; |
| nexthdr = skb_network_header(skb)[nhoff]; |
| |
| resubmit: |
| raw = raw6_local_deliver(skb, nexthdr); |
| ipprot = rcu_dereference(inet6_protos[nexthdr]); |
| if (ipprot) { |
| int ret; |
| |
| if (ipprot->flags & INET6_PROTO_FINAL) { |
| const struct ipv6hdr *hdr; |
| |
| /* Free reference early: we don't need it any more, |
| and it may hold ip_conntrack module loaded |
| indefinitely. */ |
| nf_reset(skb); |
| |
| skb_postpull_rcsum(skb, skb_network_header(skb), |
| skb_network_header_len(skb)); |
| hdr = ipv6_hdr(skb); |
| if (ipv6_addr_is_multicast(&hdr->daddr) && |
| !ipv6_chk_mcast_addr(skb->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 = ipprot->handler(skb); |
| if (ret < 0) { |
| nexthdr = -ret; |
| goto resubmit; |
| } else if (ret == 0) { |
| IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); |
| } |
| } else { |
| if (!raw) { |
| if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { |
| IP6_INC_STATS_BH(net, idev, |
| IPSTATS_MIB_INUNKNOWNPROTOS); |
| icmpv6_send(skb, ICMPV6_PARAMPROB, |
| ICMPV6_UNK_NEXTHDR, nhoff); |
| } |
| kfree_skb(skb); |
| } else { |
| IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); |
| consume_skb(skb); |
| } |
| } |
| rcu_read_unlock(); |
| return 0; |
| |
| discard: |
| IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); |
| rcu_read_unlock(); |
| kfree_skb(skb); |
| return 0; |
| } |
| |
| |
| int ip6_input(struct sk_buff *skb) |
| { |
| return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, NULL, skb, |
| skb->dev, NULL, |
| ip6_input_finish); |
| } |
| |
| int ip6_mc_input(struct sk_buff *skb) |
| { |
| const struct ipv6hdr *hdr; |
| bool deliver; |
| |
| IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev), |
| ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST, |
| skb->len); |
| |
| hdr = ipv6_hdr(skb); |
| deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); |
| |
| #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)) |
| goto out; |
| |
| deliver = true; |
| } |
| /* 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; |
| } |