diff options
Diffstat (limited to 'net/netfilter/nf_nat_ovs.c')
| -rw-r--r-- | net/netfilter/nf_nat_ovs.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/net/netfilter/nf_nat_ovs.c b/net/netfilter/nf_nat_ovs.c new file mode 100644 index 000000000..0f9a559f6 --- /dev/null +++ b/net/netfilter/nf_nat_ovs.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Support nat functions for openvswitch and used by OVS and TC conntrack. */ + +#include <net/netfilter/nf_nat.h> + +/* Modelled after nf_nat_ipv[46]_fn(). + * range is only used for new, uninitialized NAT state. + * Returns either NF_ACCEPT or NF_DROP. + */ +static int nf_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct, + enum ip_conntrack_info ctinfo, int *action, + const struct nf_nat_range2 *range, + enum nf_nat_manip_type maniptype) +{ + __be16 proto = skb_protocol(skb, true); + int hooknum, err = NF_ACCEPT; + + /* See HOOK2MANIP(). */ + if (maniptype == NF_NAT_MANIP_SRC) + hooknum = NF_INET_LOCAL_IN; /* Source NAT */ + else + hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */ + + switch (ctinfo) { + case IP_CT_RELATED: + case IP_CT_RELATED_REPLY: + if (proto == htons(ETH_P_IP) && + ip_hdr(skb)->protocol == IPPROTO_ICMP) { + if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo, + hooknum)) + err = NF_DROP; + goto out; + } else if (IS_ENABLED(CONFIG_IPV6) && proto == htons(ETH_P_IPV6)) { + __be16 frag_off; + u8 nexthdr = ipv6_hdr(skb)->nexthdr; + int hdrlen = ipv6_skip_exthdr(skb, + sizeof(struct ipv6hdr), + &nexthdr, &frag_off); + + if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) { + if (!nf_nat_icmpv6_reply_translation(skb, ct, + ctinfo, + hooknum, + hdrlen)) + err = NF_DROP; + goto out; + } + } + /* Non-ICMP, fall thru to initialize if needed. */ + fallthrough; + case IP_CT_NEW: + /* Seen it before? This can happen for loopback, retrans, + * or local packets. + */ + if (!nf_nat_initialized(ct, maniptype)) { + /* Initialize according to the NAT action. */ + err = (range && range->flags & NF_NAT_RANGE_MAP_IPS) + /* Action is set up to establish a new + * mapping. + */ + ? nf_nat_setup_info(ct, range, maniptype) + : nf_nat_alloc_null_binding(ct, hooknum); + if (err != NF_ACCEPT) + goto out; + } + break; + + case IP_CT_ESTABLISHED: + case IP_CT_ESTABLISHED_REPLY: + break; + + default: + err = NF_DROP; + goto out; + } + + err = nf_nat_packet(ct, ctinfo, hooknum, skb); +out: + if (err == NF_ACCEPT) + *action |= BIT(maniptype); + + return err; +} + +int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct, + enum ip_conntrack_info ctinfo, int *action, + const struct nf_nat_range2 *range, bool commit) +{ + enum nf_nat_manip_type maniptype; + int err, ct_action = *action; + + *action = 0; + + /* Add NAT extension if not confirmed yet. */ + if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct)) + return NF_DROP; /* Can't NAT. */ + + if (ctinfo != IP_CT_NEW && (ct->status & IPS_NAT_MASK) && + (ctinfo != IP_CT_RELATED || commit)) { + /* NAT an established or related connection like before. */ + if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) + /* This is the REPLY direction for a connection + * for which NAT was applied in the forward + * direction. Do the reverse NAT. + */ + maniptype = ct->status & IPS_SRC_NAT + ? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC; + else + maniptype = ct->status & IPS_SRC_NAT + ? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST; + } else if (ct_action & BIT(NF_NAT_MANIP_SRC)) { + maniptype = NF_NAT_MANIP_SRC; + } else if (ct_action & BIT(NF_NAT_MANIP_DST)) { + maniptype = NF_NAT_MANIP_DST; + } else { + return NF_ACCEPT; + } + + err = nf_ct_nat_execute(skb, ct, ctinfo, action, range, maniptype); + if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) { + if (ct->status & IPS_SRC_NAT) { + if (maniptype == NF_NAT_MANIP_SRC) + maniptype = NF_NAT_MANIP_DST; + else + maniptype = NF_NAT_MANIP_SRC; + + err = nf_ct_nat_execute(skb, ct, ctinfo, action, range, + maniptype); + } else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) { + err = nf_ct_nat_execute(skb, ct, ctinfo, action, NULL, + NF_NAT_MANIP_SRC); + } + } + return err; +} +EXPORT_SYMBOL_GPL(nf_ct_nat); |