net, ipv6, lwtunnel: add and use LWTUNNEL_IP6_FLAGS_BITMAP attribute

Add the ability to pass 64-bit IPv6 tunnel flags in IP tunnel core code between the userspace and the kernel. On receiving, the new attribute is preferred, the old 16-bit one is being read only if the new one is not present. On sending, there's no other options other than sending both of them, so that both old and new userspace programs could work properly. Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
alobakin · Jul 19, 2022 · 26d2f2c · 26d2f2c
1 parent 722f0c7
commit 26d2f2c
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Showing 2 changed files with 22 additions and 5 deletions.
diff --git a/include/uapi/linux/lwtunnel.h b/include/uapi/linux/lwtunnel.h
@@ -46,6 +46,7 @@ enum lwtunnel_ip6_t {
 	LWTUNNEL_IP6_FLAGS,
 	LWTUNNEL_IP6_PAD,
 	LWTUNNEL_IP6_OPTS,
+	LWTUNNEL_IP6_FLAGS_BITMAP,
 	__LWTUNNEL_IP6_MAX,
 };
 

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
@@ -957,6 +957,8 @@ static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 	[LWTUNNEL_IP6_TC]		= { .type = NLA_U8 },
 	[LWTUNNEL_IP6_FLAGS]		= { .type = NLA_U16 },
 	[LWTUNNEL_IP6_OPTS]		= { .type = NLA_NESTED },
+	[LWTUNNEL_IP6_FLAGS_BITMAP]	=
+		NLA_POLICY_BITMAP(__IP_TUNNEL_FLAG_NUM),
 };
 
 static int ip6_tun_build_state(struct net *net, struct nlattr *attr,
@@ -967,6 +969,8 @@ static int ip6_tun_build_state(struct net *net, struct nlattr *attr,
 	struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 	struct lwtunnel_state *new_state;
 	struct ip_tunnel_info *tun_info;
+	IP_TUNNEL_DECLARE_FLAGS(flags);
+	bool set_flags = false;
 	int err, opt_len;
 
 	err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
@@ -1007,14 +1011,20 @@ static int ip6_tun_build_state(struct net *net, struct nlattr *attr,
 	if (tb[LWTUNNEL_IP6_TC])
 		tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 
-	if (tb[LWTUNNEL_IP6_FLAGS]) {
-		IP_TUNNEL_DECLARE_FLAGS(flags);
+	if (tb[LWTUNNEL_IP6_FLAGS_BITMAP]) {
+		nla_get_bitmap(tb[LWTUNNEL_IP6_FLAGS_BITMAP], flags,
+			       __IP_TUNNEL_FLAG_NUM);
+		set_flags = true;
+	} else if (tb[LWTUNNEL_IP6_FLAGS]) {
 		__be16 data;
 
 		data = nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]);
 		ip_tunnel_flags_from_be16(flags, data);
-		ip_tunnel_clear_options_present(flags);
+		set_flags = true;
+	}
 
+	if (set_flags) {
+		ip_tunnel_clear_options_present(flags);
 		bitmap_or(tun_info->key.tun_flags, tun_info->key.tun_flags,
 			  flags, __IP_TUNNEL_FLAG_NUM);
 	}
@@ -1040,7 +1050,10 @@ static int ip6_tun_fill_encap_info(struct sk_buff *skb,
 	    nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
 	    nla_put_be16(skb, LWTUNNEL_IP6_FLAGS,
 			 ip_tunnel_flags_to_be16(tun_info->key.tun_flags)) ||
-	    ip_tun_fill_encap_opts(skb, LWTUNNEL_IP6_OPTS, tun_info))
+	    ip_tun_fill_encap_opts(skb, LWTUNNEL_IP6_OPTS, tun_info) ||
+	    nla_put_bitmap(skb, LWTUNNEL_IP6_FLAGS_BITMAP,
+			   tun_info->key.tun_flags, __IP_TUNNEL_FLAG_NUM,
+			   LWTUNNEL_IP6_PAD))
 		return -ENOMEM;
 
 	return 0;
@@ -1054,8 +1067,11 @@ static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 		+ nla_total_size(1)	/* LWTUNNEL_IP6_HOPLIMIT */
 		+ nla_total_size(1)	/* LWTUNNEL_IP6_TC */
 		+ nla_total_size(2)	/* LWTUNNEL_IP6_FLAGS */
-		+ ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
+		+ ip_tun_opts_nlsize(lwt_tun_info(lwtstate))
 					/* LWTUNNEL_IP6_OPTS */
+		+ nla_total_size_bitmap(__IP_TUNNEL_FLAG_NUM)
+					/* LWTUNNEL_IP6_FLAGS_BITMAP */
+		;
 }
 
 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {