net, ipv4, lwtunnel: add and use LWTUNNEL_IP_FLAGS_BITMAP attribute

Add the ability to pass 64-bit IP 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 · 722f0c7 · 722f0c7
1 parent b666eda
commit 722f0c7
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Showing 2 changed files with 22 additions and 6 deletions.
diff --git a/include/uapi/linux/lwtunnel.h b/include/uapi/linux/lwtunnel.h
@@ -30,6 +30,7 @@ enum lwtunnel_ip_t {
 	LWTUNNEL_IP_FLAGS,
 	LWTUNNEL_IP_PAD,
 	LWTUNNEL_IP_OPTS,
+	LWTUNNEL_IP_FLAGS_BITMAP,
 	__LWTUNNEL_IP_MAX,
 };
 

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
@@ -439,6 +439,8 @@ static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 	[LWTUNNEL_IP_TOS]	= { .type = NLA_U8 },
 	[LWTUNNEL_IP_FLAGS]	= { .type = NLA_U16 },
 	[LWTUNNEL_IP_OPTS]	= { .type = NLA_NESTED },
+	[LWTUNNEL_IP_FLAGS_BITMAP]	=
+		NLA_POLICY_BITMAP(__IP_TUNNEL_FLAG_NUM),
 };
 
 static const struct nla_policy ip_opts_policy[LWTUNNEL_IP_OPTS_MAX + 1] = {
@@ -658,6 +660,8 @@ static int ip_tun_build_state(struct net *net, struct nlattr *attr,
 	struct nlattr *tb[LWTUNNEL_IP_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_IP_MAX, attr,
@@ -706,13 +710,18 @@ static int ip_tun_build_state(struct net *net, struct nlattr *attr,
 	if (tb[LWTUNNEL_IP_TOS])
 		tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 
-	if (tb[LWTUNNEL_IP_FLAGS]) {
-		IP_TUNNEL_DECLARE_FLAGS(flags);
-
+	if (tb[LWTUNNEL_IP_FLAGS_BITMAP]) {
+		nla_get_bitmap(tb[LWTUNNEL_IP_FLAGS_BITMAP], flags,
+			       __IP_TUNNEL_FLAG_NUM);
+		set_flags = true;
+	} else if (tb[LWTUNNEL_IP_FLAGS]) {
 		ip_tunnel_flags_from_be16(flags,
 					  nla_get_be16(tb[LWTUNNEL_IP_FLAGS]));
-		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);
 	}
@@ -855,7 +864,10 @@ static int ip_tun_fill_encap_info(struct sk_buff *skb,
 	    nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 	    nla_put_be16(skb, LWTUNNEL_IP_FLAGS,
 			 ip_tunnel_flags_to_be16(tun_info->key.tun_flags)) ||
-	    ip_tun_fill_encap_opts(skb, LWTUNNEL_IP_OPTS, tun_info))
+	    ip_tun_fill_encap_opts(skb, LWTUNNEL_IP_OPTS, tun_info) ||
+	    nla_put_bitmap(skb, LWTUNNEL_IP_FLAGS_BITMAP,
+			   tun_info->key.tun_flags, __IP_TUNNEL_FLAG_NUM,
+			   LWTUNNEL_IP_PAD))
 		return -ENOMEM;
 
 	return 0;
@@ -908,8 +920,11 @@ static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 		+ nla_total_size(1)	/* LWTUNNEL_IP_TOS */
 		+ nla_total_size(1)	/* LWTUNNEL_IP_TTL */
 		+ nla_total_size(2)	/* LWTUNNEL_IP_FLAGS */
-		+ ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
+		+ ip_tun_opts_nlsize(lwt_tun_info(lwtstate))
 					/* LWTUNNEL_IP_OPTS */
+		+ nla_total_size_bitmap(__IP_TUNNEL_FLAG_NUM)
+					/* LWTUNNEL_IP_FLAGS_BITMAP */
+		;
 }
 
 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)