geneve: support setting IPv6 flow label

This work adds support for setting the IPv6 flow label for geneve per
device and through collect metadata (ip_tunnel_key) frontends. Also here,
the geneve dst cache does not need any special considerations, for the
cases where caches can be used, the label is static per cache.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/geneve.c

@@ -68,6 +68,7 @@ struct geneve_dev {
 	u8                 tos;		/* TOS override */
 	union geneve_addr  remote;	/* IP address for link partner */
 	struct list_head   next;	/* geneve's per namespace list */
+	__be32		   label;	/* IPv6 flowlabel override */
 	__be16		   dst_port;
 	bool		   collect_md;
 	struct gro_cells   gro_cells;
@@ -846,6 +847,7 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 		fl6->daddr = info->key.u.ipv6.dst;
 		fl6->saddr = info->key.u.ipv6.src;
 		fl6->flowi6_tos = RT_TOS(info->key.tos);
+		fl6->flowlabel = info->key.label;
 		dst_cache = &info->dst_cache;
 	} else {
 		prio = geneve->tos;
@@ -857,6 +859,7 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 		}
 
 		fl6->flowi6_tos = RT_TOS(prio);
+		fl6->flowlabel = geneve->label;
 		fl6->daddr = geneve->remote.sin6.sin6_addr;
 		dst_cache = &geneve->dst_cache;
 	}
@@ -998,6 +1001,7 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	struct flowi6 fl6;
 	__u8 prio, ttl;
 	__be16 sport;
+	__be32 label;
 	bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
 	u32 flags = geneve->flags;
 
@@ -1041,6 +1045,7 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 
 		prio = ip_tunnel_ecn_encap(key->tos, iip, skb);
 		ttl = key->ttl;
+		label = info->key.label;
 	} else {
 		err = geneve6_build_skb(dst, skb, 0, geneve->vni,
 					0, NULL, flags, xnet);
@@ -1052,9 +1057,11 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 		if (!ttl && ipv6_addr_is_multicast(&fl6.daddr))
 			ttl = 1;
 		ttl = ttl ? : ip6_dst_hoplimit(dst);
+		label = geneve->label;
 	}
+
 	udp_tunnel6_xmit_skb(dst, gs6->sock->sk, skb, dev,
-			     &fl6.saddr, &fl6.daddr, prio, ttl, 0,
+			     &fl6.saddr, &fl6.daddr, prio, ttl, label,
 			     sport, geneve->dst_port,
 			     !!(flags & GENEVE_F_UDP_ZERO_CSUM6_TX));
 	return NETDEV_TX_OK;
@@ -1238,6 +1245,7 @@ static const struct nla_policy geneve_policy[IFLA_GENEVE_MAX + 1] = {
 	[IFLA_GENEVE_REMOTE6]		= { .len = sizeof(struct in6_addr) },
 	[IFLA_GENEVE_TTL]		= { .type = NLA_U8 },
 	[IFLA_GENEVE_TOS]		= { .type = NLA_U8 },
+	[IFLA_GENEVE_LABEL]		= { .type = NLA_U32 },
 	[IFLA_GENEVE_PORT]		= { .type = NLA_U16 },
 	[IFLA_GENEVE_COLLECT_METADATA]	= { .type = NLA_FLAG },
 	[IFLA_GENEVE_UDP_CSUM]		= { .type = NLA_U8 },
@@ -1295,8 +1303,8 @@ static struct geneve_dev *geneve_find_dev(struct geneve_net *gn,
 
 static int geneve_configure(struct net *net, struct net_device *dev,
 			    union geneve_addr *remote,
-			    __u32 vni, __u8 ttl, __u8 tos, __be16 dst_port,
-			    bool metadata, u32 flags)
+			    __u32 vni, __u8 ttl, __u8 tos, __be32 label,
+			    __be16 dst_port, bool metadata, u32 flags)
 {
 	struct geneve_net *gn = net_generic(net, geneve_net_id);
 	struct geneve_dev *t, *geneve = netdev_priv(dev);
@@ -1306,7 +1314,7 @@ static int geneve_configure(struct net *net, struct net_device *dev,
 	if (!remote)
 		return -EINVAL;
 	if (metadata &&
-	    (remote->sa.sa_family != AF_UNSPEC || vni || tos || ttl))
+	    (remote->sa.sa_family != AF_UNSPEC || vni || tos || ttl || label))
 		return -EINVAL;
 
 	geneve->net = net;
@@ -1321,10 +1329,14 @@ static int geneve_configure(struct net *net, struct net_device *dev,
 	    (remote->sa.sa_family == AF_INET6 &&
 	     ipv6_addr_is_multicast(&remote->sin6.sin6_addr)))
 		return -EINVAL;
+	if (label && remote->sa.sa_family != AF_INET6)
+		return -EINVAL;
+
 	geneve->remote = *remote;
 
 	geneve->ttl = ttl;
 	geneve->tos = tos;
+	geneve->label = label;
 	geneve->dst_port = dst_port;
 	geneve->collect_md = metadata;
 	geneve->flags = flags;
@@ -1367,6 +1379,7 @@ static int geneve_newlink(struct net *net, struct net_device *dev,
 	__u8 ttl = 0, tos = 0;
 	bool metadata = false;
 	union geneve_addr remote = geneve_remote_unspec;
+	__be32 label = 0;
 	__u32 vni = 0;
 	u32 flags = 0;
 
@@ -1403,6 +1416,10 @@ static int geneve_newlink(struct net *net, struct net_device *dev,
 	if (data[IFLA_GENEVE_TOS])
 		tos = nla_get_u8(data[IFLA_GENEVE_TOS]);
 
+	if (data[IFLA_GENEVE_LABEL])
+		label = nla_get_be32(data[IFLA_GENEVE_LABEL]) &
+			IPV6_FLOWLABEL_MASK;
+
 	if (data[IFLA_GENEVE_PORT])
 		dst_port = nla_get_be16(data[IFLA_GENEVE_PORT]);
 
@@ -1421,8 +1438,8 @@ static int geneve_newlink(struct net *net, struct net_device *dev,
 	    nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_RX]))
 		flags |= GENEVE_F_UDP_ZERO_CSUM6_RX;
 
-	return geneve_configure(net, dev, &remote, vni, ttl, tos, dst_port,
-				metadata, flags);
+	return geneve_configure(net, dev, &remote, vni, ttl, tos, label,
+				dst_port, metadata, flags);
 }
 
 static void geneve_dellink(struct net_device *dev, struct list_head *head)
@@ -1439,6 +1456,7 @@ static size_t geneve_get_size(const struct net_device *dev)
 		nla_total_size(sizeof(struct in6_addr)) + /* IFLA_GENEVE_REMOTE{6} */
 		nla_total_size(sizeof(__u8)) +  /* IFLA_GENEVE_TTL */
 		nla_total_size(sizeof(__u8)) +  /* IFLA_GENEVE_TOS */
+		nla_total_size(sizeof(__be32)) +  /* IFLA_GENEVE_LABEL */
 		nla_total_size(sizeof(__be16)) +  /* IFLA_GENEVE_PORT */
 		nla_total_size(0) +	 /* IFLA_GENEVE_COLLECT_METADATA */
 		nla_total_size(sizeof(__u8)) + /* IFLA_GENEVE_UDP_CSUM */
@@ -1469,7 +1487,8 @@ static int geneve_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	}
 
 	if (nla_put_u8(skb, IFLA_GENEVE_TTL, geneve->ttl) ||
-	    nla_put_u8(skb, IFLA_GENEVE_TOS, geneve->tos))
+	    nla_put_u8(skb, IFLA_GENEVE_TOS, geneve->tos) ||
+	    nla_put_be32(skb, IFLA_GENEVE_LABEL, geneve->label))
 		goto nla_put_failure;
 
 	if (nla_put_be16(skb, IFLA_GENEVE_PORT, geneve->dst_port))
@@ -1521,7 +1540,7 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
 		return dev;
 
 	err = geneve_configure(net, dev, &geneve_remote_unspec,
-			       0, 0, 0, htons(dst_port), true,
+			       0, 0, 0, 0, htons(dst_port), true,
 			       GENEVE_F_UDP_ZERO_CSUM6_RX);
 	if (err)
 		goto err;

include/uapi/linux/if_link.h

@@ -479,6 +479,7 @@ enum {
 	IFLA_GENEVE_UDP_CSUM,
 	IFLA_GENEVE_UDP_ZERO_CSUM6_TX,
 	IFLA_GENEVE_UDP_ZERO_CSUM6_RX,
+	IFLA_GENEVE_LABEL,
 	__IFLA_GENEVE_MAX
 };
 #define IFLA_GENEVE_MAX	(__IFLA_GENEVE_MAX - 1)