1 files changed, 104 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_ovs.c b/net/netfilter/nf_conntrack_ovs.c
new file mode 100644
index 000000000000..eff4d53f8b8c
--- /dev/null
+++ b/net/netfilter/nf_conntrack_ovs.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Support ct functions for openvswitch and used by OVS and TC conntrack. */
+
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_seqadj.h>
+#include <net/ip.h>
+
+/* 'skb' should already be pulled to nh_ofs. */
+int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
+		 enum ip_conntrack_info ctinfo, u16 proto)
+{
+	const struct nf_conntrack_helper *helper;
+	const struct nf_conn_help *help;
+	unsigned int protoff;
+	int err;
+
+	if (ctinfo == IP_CT_RELATED_REPLY)
+		return NF_ACCEPT;
+
+	help = nfct_help(ct);
+	if (!help)
+		return NF_ACCEPT;
+
+	helper = rcu_dereference(help->helper);
+	if (!helper)
+		return NF_ACCEPT;
+
+	if (helper->tuple.src.l3num != NFPROTO_UNSPEC &&
+	    helper->tuple.src.l3num != proto)
+		return NF_ACCEPT;
+
+	switch (proto) {
+	case NFPROTO_IPV4:
+		protoff = ip_hdrlen(skb);
+		proto = ip_hdr(skb)->protocol;
+		break;
+	case NFPROTO_IPV6: {
+		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
+		__be16 frag_off;
+		int ofs;
+
+		ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
+				       &frag_off);
+		if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
+			pr_debug("proto header not found\n");
+			return NF_ACCEPT;
+		}
+		protoff = ofs;
+		proto = nexthdr;
+		break;
+	}
+	default:
+		WARN_ONCE(1, "helper invoked on non-IP family!");
+		return NF_DROP;
+	}
+
+	if (helper->tuple.dst.protonum != proto)
+		return NF_ACCEPT;
+
+	err = helper->help(skb, protoff, ct, ctinfo);
+	if (err != NF_ACCEPT)
+		return err;
+
+	/* Adjust seqs after helper.  This is needed due to some helpers (e.g.,
+	 * FTP with NAT) adusting the TCP payload size when mangling IP
+	 * addresses and/or port numbers in the text-based control connection.
+	 */
+	if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
+	    !nf_ct_seq_adjust(skb, ct, ctinfo, protoff))
+		return NF_DROP;
+	return NF_ACCEPT;
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper);
+
+int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family,
+		     u8 proto, bool nat, struct nf_conntrack_helper **hp)
+{
+	struct nf_conntrack_helper *helper;
+	struct nf_conn_help *help;
+	int ret = 0;
+
+	helper = nf_conntrack_helper_try_module_get(name, family, proto);
+	if (!helper)
+		return -EINVAL;
+
+	help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
+	if (!help) {
+		nf_conntrack_helper_put(helper);
+		return -ENOMEM;
+	}
+#if IS_ENABLED(CONFIG_NF_NAT)
+	if (nat) {
+		ret = nf_nat_helper_try_module_get(name, family, proto);
+		if (ret) {
+			nf_conntrack_helper_put(helper);
+			return ret;
+		}
+	}
+#endif
+	rcu_assign_pointer(help->helper, helper);
+	*hp = helper;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_ct_add_helper);