455 lines
12 KiB
C
455 lines
12 KiB
C
/*
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* Copyright (C)2004 USAGI/WIDE Project
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Author:
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* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
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*/
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#include <linux/types.h>
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#include <linux/ipv6.h>
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#include <linux/in6.h>
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#include <linux/netfilter.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/icmp.h>
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#include <net/ipv6.h>
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#include <net/inet_frag.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_l3proto.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_zones.h>
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#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
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#include <net/netfilter/nf_nat_helper.h>
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#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
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#include <net/netfilter/nf_log.h>
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static bool ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
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struct nf_conntrack_tuple *tuple)
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{
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const u_int32_t *ap;
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u_int32_t _addrs[8];
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ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr),
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sizeof(_addrs), _addrs);
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if (ap == NULL)
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return false;
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memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
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memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
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return true;
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}
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static bool ipv6_invert_tuple(struct nf_conntrack_tuple *tuple,
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const struct nf_conntrack_tuple *orig)
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{
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memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6));
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memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6));
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return true;
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}
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static int ipv6_print_tuple(struct seq_file *s,
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const struct nf_conntrack_tuple *tuple)
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{
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return seq_printf(s, "src=%pI6 dst=%pI6 ",
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tuple->src.u3.ip6, tuple->dst.u3.ip6);
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}
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static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
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unsigned int *dataoff, u_int8_t *protonum)
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{
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unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
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__be16 frag_off;
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int protoff;
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u8 nexthdr;
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if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
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&nexthdr, sizeof(nexthdr)) != 0) {
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pr_debug("ip6_conntrack_core: can't get nexthdr\n");
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return -NF_ACCEPT;
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}
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protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
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/*
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* (protoff == skb->len) mean that the packet doesn't have no data
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* except of IPv6 & ext headers. but it's tracked anyway. - YK
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*/
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if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
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pr_debug("ip6_conntrack_core: can't find proto in pkt\n");
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return -NF_ACCEPT;
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}
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*dataoff = protoff;
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*protonum = nexthdr;
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return NF_ACCEPT;
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}
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static unsigned int ipv6_helper(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct nf_conn *ct;
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const struct nf_conn_help *help;
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const struct nf_conntrack_helper *helper;
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enum ip_conntrack_info ctinfo;
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unsigned int ret;
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__be16 frag_off;
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int protoff;
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u8 nexthdr;
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/* This is where we call the helper: as the packet goes out. */
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct || ctinfo == IP_CT_RELATED_REPLY)
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return NF_ACCEPT;
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help = nfct_help(ct);
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if (!help)
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return NF_ACCEPT;
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/* rcu_read_lock()ed by nf_hook_slow */
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helper = rcu_dereference(help->helper);
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if (!helper)
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return NF_ACCEPT;
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nexthdr = ipv6_hdr(skb)->nexthdr;
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protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
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&frag_off);
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if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
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pr_debug("proto header not found\n");
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return NF_ACCEPT;
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}
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ret = helper->help(skb, protoff, ct, ctinfo);
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if (ret != NF_ACCEPT && (ret & NF_VERDICT_MASK) != NF_QUEUE) {
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nf_log_packet(NFPROTO_IPV6, hooknum, skb, in, out, NULL,
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"nf_ct_%s: dropping packet", helper->name);
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}
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return ret;
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}
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static unsigned int ipv6_confirm(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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unsigned char pnum = ipv6_hdr(skb)->nexthdr;
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int protoff;
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__be16 frag_off;
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct || ctinfo == IP_CT_RELATED_REPLY)
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goto out;
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protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
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&frag_off);
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if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
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pr_debug("proto header not found\n");
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goto out;
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}
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/* adjust seqs for loopback traffic only in outgoing direction */
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if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
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!nf_is_loopback_packet(skb)) {
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typeof(nf_nat_seq_adjust_hook) seq_adjust;
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seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
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if (!seq_adjust ||
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!seq_adjust(skb, ct, ctinfo, protoff)) {
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NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
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return NF_DROP;
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}
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}
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out:
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/* We've seen it coming out the other side: confirm it */
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return nf_conntrack_confirm(skb);
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}
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static unsigned int __ipv6_conntrack_in(struct net *net,
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unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct sk_buff *reasm = skb->nfct_reasm;
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const struct nf_conn_help *help;
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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/* This packet is fragmented and has reassembled packet. */
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if (reasm) {
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/* Reassembled packet isn't parsed yet ? */
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if (!reasm->nfct) {
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unsigned int ret;
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ret = nf_conntrack_in(net, PF_INET6, hooknum, reasm);
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if (ret != NF_ACCEPT)
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return ret;
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}
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/* Conntrack helpers need the entire reassembled packet in the
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* POST_ROUTING hook. In case of unconfirmed connections NAT
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* might reassign a helper, so the entire packet is also
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* required.
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*/
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ct = nf_ct_get(reasm, &ctinfo);
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if (ct != NULL && !nf_ct_is_untracked(ct)) {
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help = nfct_help(ct);
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if ((help && help->helper) || !nf_ct_is_confirmed(ct)) {
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nf_conntrack_get_reasm(skb);
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NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, reasm,
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(struct net_device *)in,
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(struct net_device *)out,
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okfn, NF_IP6_PRI_CONNTRACK + 1);
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return NF_DROP_ERR(-ECANCELED);
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}
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}
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nf_conntrack_get(reasm->nfct);
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skb->nfct = reasm->nfct;
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skb->nfctinfo = reasm->nfctinfo;
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return NF_ACCEPT;
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}
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return nf_conntrack_in(net, PF_INET6, hooknum, skb);
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}
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static unsigned int ipv6_conntrack_in(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return __ipv6_conntrack_in(dev_net(in), hooknum, skb, in, out, okfn);
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}
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static unsigned int ipv6_conntrack_local(unsigned int hooknum,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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/* root is playing with raw sockets. */
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if (skb->len < sizeof(struct ipv6hdr)) {
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net_notice_ratelimited("ipv6_conntrack_local: packet too short\n");
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return NF_ACCEPT;
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}
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return __ipv6_conntrack_in(dev_net(out), hooknum, skb, in, out, okfn);
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}
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static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = {
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{
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.hook = ipv6_conntrack_in,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP6_PRI_CONNTRACK,
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},
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{
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.hook = ipv6_conntrack_local,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_LOCAL_OUT,
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.priority = NF_IP6_PRI_CONNTRACK,
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},
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{
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.hook = ipv6_helper,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_POST_ROUTING,
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.priority = NF_IP6_PRI_CONNTRACK_HELPER,
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},
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{
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.hook = ipv6_confirm,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_POST_ROUTING,
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.priority = NF_IP6_PRI_LAST,
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},
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{
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.hook = ipv6_helper,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_LOCAL_IN,
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.priority = NF_IP6_PRI_CONNTRACK_HELPER,
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},
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{
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.hook = ipv6_confirm,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV6,
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.hooknum = NF_INET_LOCAL_IN,
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.priority = NF_IP6_PRI_LAST-1,
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},
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};
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_conntrack.h>
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static int ipv6_tuple_to_nlattr(struct sk_buff *skb,
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const struct nf_conntrack_tuple *tuple)
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{
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if (nla_put(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
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&tuple->src.u3.ip6) ||
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nla_put(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
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&tuple->dst.u3.ip6))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static const struct nla_policy ipv6_nla_policy[CTA_IP_MAX+1] = {
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[CTA_IP_V6_SRC] = { .len = sizeof(u_int32_t)*4 },
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[CTA_IP_V6_DST] = { .len = sizeof(u_int32_t)*4 },
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};
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static int ipv6_nlattr_to_tuple(struct nlattr *tb[],
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struct nf_conntrack_tuple *t)
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{
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if (!tb[CTA_IP_V6_SRC] || !tb[CTA_IP_V6_DST])
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return -EINVAL;
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memcpy(&t->src.u3.ip6, nla_data(tb[CTA_IP_V6_SRC]),
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sizeof(u_int32_t) * 4);
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memcpy(&t->dst.u3.ip6, nla_data(tb[CTA_IP_V6_DST]),
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sizeof(u_int32_t) * 4);
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return 0;
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}
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static int ipv6_nlattr_tuple_size(void)
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{
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return nla_policy_len(ipv6_nla_policy, CTA_IP_MAX + 1);
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}
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#endif
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struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 __read_mostly = {
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.l3proto = PF_INET6,
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.name = "ipv6",
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.pkt_to_tuple = ipv6_pkt_to_tuple,
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.invert_tuple = ipv6_invert_tuple,
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.print_tuple = ipv6_print_tuple,
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.get_l4proto = ipv6_get_l4proto,
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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.tuple_to_nlattr = ipv6_tuple_to_nlattr,
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.nlattr_tuple_size = ipv6_nlattr_tuple_size,
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.nlattr_to_tuple = ipv6_nlattr_to_tuple,
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.nla_policy = ipv6_nla_policy,
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#endif
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.me = THIS_MODULE,
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};
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MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>");
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static int ipv6_net_init(struct net *net)
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{
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int ret = 0;
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ret = nf_conntrack_l4proto_register(net,
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&nf_conntrack_l4proto_tcp6);
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if (ret < 0) {
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printk(KERN_ERR "nf_conntrack_l4proto_tcp6: protocol register failed\n");
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goto out;
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}
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ret = nf_conntrack_l4proto_register(net,
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&nf_conntrack_l4proto_udp6);
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if (ret < 0) {
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printk(KERN_ERR "nf_conntrack_l4proto_udp6: protocol register failed\n");
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goto cleanup_tcp6;
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}
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ret = nf_conntrack_l4proto_register(net,
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&nf_conntrack_l4proto_icmpv6);
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if (ret < 0) {
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printk(KERN_ERR "nf_conntrack_l4proto_icmp6: protocol register failed\n");
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goto cleanup_udp6;
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}
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ret = nf_conntrack_l3proto_register(net,
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&nf_conntrack_l3proto_ipv6);
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if (ret < 0) {
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printk(KERN_ERR "nf_conntrack_l3proto_ipv6: protocol register failed\n");
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goto cleanup_icmpv6;
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}
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return 0;
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cleanup_icmpv6:
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_icmpv6);
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cleanup_udp6:
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_udp6);
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cleanup_tcp6:
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_tcp6);
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out:
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return ret;
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}
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static void ipv6_net_exit(struct net *net)
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{
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nf_conntrack_l3proto_unregister(net,
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&nf_conntrack_l3proto_ipv6);
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_icmpv6);
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_udp6);
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nf_conntrack_l4proto_unregister(net,
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&nf_conntrack_l4proto_tcp6);
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}
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static struct pernet_operations ipv6_net_ops = {
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.init = ipv6_net_init,
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.exit = ipv6_net_exit,
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};
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static int __init nf_conntrack_l3proto_ipv6_init(void)
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{
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int ret = 0;
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need_conntrack();
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nf_defrag_ipv6_enable();
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ret = register_pernet_subsys(&ipv6_net_ops);
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if (ret < 0)
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goto cleanup_pernet;
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ret = nf_register_hooks(ipv6_conntrack_ops,
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ARRAY_SIZE(ipv6_conntrack_ops));
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if (ret < 0) {
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pr_err("nf_conntrack_ipv6: can't register pre-routing defrag "
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"hook.\n");
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goto cleanup_ipv6;
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}
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return ret;
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cleanup_ipv6:
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unregister_pernet_subsys(&ipv6_net_ops);
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cleanup_pernet:
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return ret;
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}
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static void __exit nf_conntrack_l3proto_ipv6_fini(void)
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{
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synchronize_net();
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nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
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unregister_pernet_subsys(&ipv6_net_ops);
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}
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module_init(nf_conntrack_l3proto_ipv6_init);
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module_exit(nf_conntrack_l3proto_ipv6_fini);
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