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ebddb14049
There are two nat functions are nearly the same in both OVS and TC code, (ovs_)ct_nat_execute() and ovs_ct_nat/tcf_ct_act_nat(). This patch creates nf_nat_ovs.c under netfilter and moves them there then exports nf_ct_nat() so that it can be shared by both OVS and TC, and keeps the nat (type) check and nat flag update in OVS and TC's own place, as these parts are different between OVS and TC. Note that in OVS nat function it was using skb->protocol to get the proto as it already skips vlans in key_extract(), while it doesn't in TC, and TC has to call skb_protocol() to get proto. So in nf_ct_nat_execute(), we keep using skb_protocol() which works for both OVS and TC contrack. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Aaron Conole <aconole@redhat.com> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
135 lines
3.8 KiB
C
135 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Support nat functions for openvswitch and used by OVS and TC conntrack. */
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#include <net/netfilter/nf_nat.h>
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/* Modelled after nf_nat_ipv[46]_fn().
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* range is only used for new, uninitialized NAT state.
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* Returns either NF_ACCEPT or NF_DROP.
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*/
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static int nf_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
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enum ip_conntrack_info ctinfo, int *action,
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const struct nf_nat_range2 *range,
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enum nf_nat_manip_type maniptype)
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{
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__be16 proto = skb_protocol(skb, true);
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int hooknum, err = NF_ACCEPT;
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/* See HOOK2MANIP(). */
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if (maniptype == NF_NAT_MANIP_SRC)
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hooknum = NF_INET_LOCAL_IN; /* Source NAT */
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else
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hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
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switch (ctinfo) {
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case IP_CT_RELATED:
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case IP_CT_RELATED_REPLY:
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if (proto == htons(ETH_P_IP) &&
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ip_hdr(skb)->protocol == IPPROTO_ICMP) {
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if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
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hooknum))
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err = NF_DROP;
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goto out;
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} else if (IS_ENABLED(CONFIG_IPV6) && proto == htons(ETH_P_IPV6)) {
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__be16 frag_off;
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u8 nexthdr = ipv6_hdr(skb)->nexthdr;
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int hdrlen = ipv6_skip_exthdr(skb,
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sizeof(struct ipv6hdr),
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&nexthdr, &frag_off);
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if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
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if (!nf_nat_icmpv6_reply_translation(skb, ct,
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ctinfo,
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hooknum,
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hdrlen))
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err = NF_DROP;
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goto out;
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}
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}
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/* Non-ICMP, fall thru to initialize if needed. */
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fallthrough;
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case IP_CT_NEW:
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/* Seen it before? This can happen for loopback, retrans,
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* or local packets.
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*/
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if (!nf_nat_initialized(ct, maniptype)) {
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/* Initialize according to the NAT action. */
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err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
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/* Action is set up to establish a new
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* mapping.
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*/
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? nf_nat_setup_info(ct, range, maniptype)
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: nf_nat_alloc_null_binding(ct, hooknum);
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if (err != NF_ACCEPT)
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goto out;
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}
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break;
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case IP_CT_ESTABLISHED:
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case IP_CT_ESTABLISHED_REPLY:
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break;
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default:
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err = NF_DROP;
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goto out;
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}
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err = nf_nat_packet(ct, ctinfo, hooknum, skb);
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if (err == NF_ACCEPT)
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*action |= BIT(maniptype);
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out:
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return err;
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}
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int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct,
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enum ip_conntrack_info ctinfo, int *action,
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const struct nf_nat_range2 *range, bool commit)
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{
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enum nf_nat_manip_type maniptype;
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int err, ct_action = *action;
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*action = 0;
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/* Add NAT extension if not confirmed yet. */
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if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
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return NF_DROP; /* Can't NAT. */
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if (ctinfo != IP_CT_NEW && (ct->status & IPS_NAT_MASK) &&
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(ctinfo != IP_CT_RELATED || commit)) {
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/* NAT an established or related connection like before. */
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if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
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/* This is the REPLY direction for a connection
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* for which NAT was applied in the forward
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* direction. Do the reverse NAT.
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*/
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maniptype = ct->status & IPS_SRC_NAT
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? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
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else
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maniptype = ct->status & IPS_SRC_NAT
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? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
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} else if (ct_action & BIT(NF_NAT_MANIP_SRC)) {
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maniptype = NF_NAT_MANIP_SRC;
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} else if (ct_action & BIT(NF_NAT_MANIP_DST)) {
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maniptype = NF_NAT_MANIP_DST;
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} else {
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return NF_ACCEPT;
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}
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err = nf_ct_nat_execute(skb, ct, ctinfo, action, range, maniptype);
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if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
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if (ct->status & IPS_SRC_NAT) {
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if (maniptype == NF_NAT_MANIP_SRC)
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maniptype = NF_NAT_MANIP_DST;
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else
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maniptype = NF_NAT_MANIP_SRC;
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err = nf_ct_nat_execute(skb, ct, ctinfo, action, range,
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maniptype);
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} else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
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err = nf_ct_nat_execute(skb, ct, ctinfo, action, NULL,
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NF_NAT_MANIP_SRC);
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}
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(nf_ct_nat);
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