/* * IPv6 input * Linux INET6 implementation * * Authors: * Pedro Roque * Ian P. Morris * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_AVM_PA #include #endif 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; 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 && ipprot->early_demux) ipprot->early_demux(skb); } if (!skb_valid_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(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)); #ifdef CONFIG_AVM_PA AVM_PKT_INFO(skb)->ptype_pid_handle = AVM_PA_PTYPE_DEVINFO(pt)->pid_handle; #endif /* * 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 * 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; /* 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 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, net, NULL, skb, dev, NULL, ip6_rcv_finish); err: __IP6_INC_STATS(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 net *net, struct sock *sk, struct sk_buff *skb) { const struct inet6_protocol *ipprot; struct inet6_dev *idev; unsigned int nhoff; int nexthdr; bool raw; bool have_final = false; /* * Parse extension headers */ rcu_read_lock(); resubmit: 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_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; /* 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(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) { 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); } } rcu_read_unlock(); return 0; discard: __IP6_INC_STATS(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, 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) { const struct ipv6hdr *hdr; bool deliver; __IP6_UPD_PO_STATS(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)) 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; }