ip_tunnel: convert __be16 tunnel flags to bitmaps

Historically, tunnel flags like TUNNEL_CSUM or TUNNEL_ERSPAN_OPT
have been defined as __be16. Now all of those 16 bits are occupied
and there's no more free space for new flags.
It can't be simply switched to a bigger container with no
adjustments to the values, since it's an explicit Endian storage,
and on LE systems (__be16)0x0001 equals to
(__be64)0x0001000000000000.
We could probably define new 64-bit flags depending on the
Endianness, i.e. (__be64)0x0001 on BE and (__be64)0x00010000... on
LE, but that would introduce an Endianness dependency and spawn a
ton of Sparse warnings. To mitigate them, all of those places which
were adjusted with this change would be touched anyway, so why not
define stuff properly if there's no choice.

Define IP_TUNNEL_*_BIT counterparts as a bit number instead of the
value already coded and a fistful of <16 <-> bitmap> converters and
helpers. The two flags which have a different bit position are
SIT_ISATAP_BIT and VTI_ISVTI_BIT, as they were defined not as
__cpu_to_be16(), but as (__force __be16), i.e. had different
positions on LE and BE. Now they both have strongly defined places.
Change all __be16 fields which were used to store those flags, to
IP_TUNNEL_DECLARE_FLAGS() -> DECLARE_BITMAP(__IP_TUNNEL_FLAG_NUM) ->
unsigned long[1] for now, and replace all TUNNEL_* occurrences to
their bitmap counterparts. Use the converters in the places which talk
to the userspace, hardware (NFP) or other hosts (GRE header). The rest
must explicitly use the new flags only. This must be done at once,
otherwise there will be too many conversions throughout the code in
the intermediate commits.
Finally, disable the old __be16 flags for use in the kernel code
(except for the two 'irregular' flags mentioned above), to prevent
any accidental (mis)use of them. For the userspace, nothing is
changed, only additions were made.

Most noticeable bloat-o-meter difference (.text):

vmlinux:	307/-1 (306)
gre.ko:		62/0 (62)
ip_gre.ko:	941/-217 (724)	[*]
ip_tunnel.ko:	390/-900 (-510)	[**]
ip_vti.ko:	138/0 (138)
ip6_gre.ko:	534/-18 (516)	[*]
ip6_tunnel.ko:	118/-10 (108)

[*] gre_flags_to_tnl_flags() grew, but still is inlined
[**] ip_tunnel_find() got uninlined, hence such decrease

The average code size increase in non-extreme case is 100-200 bytes
per module, mostly due to sizeof(long) > sizeof(__be16), as
%__IP_TUNNEL_FLAG_NUM is less than %BITS_PER_LONG and the compilers
are able to expand the majority of bitmap_*() calls here into direct
operations on scalars.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 78 insertions, 49 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 8853c065a985..3c46a7fef8db 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -265,6 +265,7 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	struct net *net = dev_net(skb->dev);
 	struct metadata_dst *tun_dst = NULL;
 	struct erspan_base_hdr *ershdr;
+	IP_TUNNEL_DECLARE_FLAGS(flags);
 	struct ip_tunnel_net *itn;
 	struct ip_tunnel *tunnel;
 	const struct iphdr *iph;
@@ -272,18 +273,20 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	int ver;
 	int len;
 
+	ip_tunnel_flags_copy(flags, tpi->flags);
+
 	itn = net_generic(net, erspan_net_id);
 	iph = ip_hdr(skb);
 	if (is_erspan_type1(gre_hdr_len)) {
 		ver = 0;
-		tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
-					  tpi->flags | TUNNEL_NO_KEY,
+		__set_bit(IP_TUNNEL_NO_KEY_BIT, flags);
+		tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, flags,
 					  iph->saddr, iph->daddr, 0);
 	} else {
 		ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
 		ver = ershdr->ver;
-		tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
-					  tpi->flags | TUNNEL_KEY,
+		__set_bit(IP_TUNNEL_KEY_BIT, flags);
+		tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, flags,
 					  iph->saddr, iph->daddr, tpi->key);
 	}
 
@@ -307,10 +310,9 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 			struct ip_tunnel_info *info;
 			unsigned char *gh;
 			__be64 tun_id;
-			__be16 flags;
 
-			tpi->flags |= TUNNEL_KEY;
-			flags = tpi->flags;
+			__set_bit(IP_TUNNEL_KEY_BIT, tpi->flags);
+			ip_tunnel_flags_copy(flags, tpi->flags);
 			tun_id = key32_to_tunnel_id(tpi->key);
 
 			tun_dst = ip_tun_rx_dst(skb, flags,
@@ -333,7 +335,8 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 						       ERSPAN_V2_MDSIZE);
 
 			info = &tun_dst->u.tun_info;
-			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
+			__set_bit(IP_TUNNEL_ERSPAN_OPT_BIT,
+				  info->key.tun_flags);
 			info->options_len = sizeof(*md);
 		}
 
@@ -376,10 +379,13 @@ static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 
 		tnl_params = &tunnel->parms.iph;
 		if (tunnel->collect_md || tnl_params->daddr == 0) {
-			__be16 flags;
+			IP_TUNNEL_DECLARE_FLAGS(flags) = { };
 			__be64 tun_id;
 
-			flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
+			__set_bit(IP_TUNNEL_CSUM_BIT, flags);
+			__set_bit(IP_TUNNEL_KEY_BIT, flags);
+			ip_tunnel_flags_and(flags, tpi->flags, flags);
+
 			tun_id = key32_to_tunnel_id(tpi->key);
 			tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
 			if (!tun_dst)
@@ -459,12 +465,15 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		       __be16 proto)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	__be16 flags = tunnel->parms.o_flags;
+	IP_TUNNEL_DECLARE_FLAGS(flags);
+
+	ip_tunnel_flags_copy(flags, tunnel->parms.o_flags);
 
 	/* Push GRE header. */
 	gre_build_header(skb, tunnel->tun_hlen,
 			 flags, proto, tunnel->parms.o_key,
-			 (flags & TUNNEL_SEQ) ? htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
+			 test_bit(IP_TUNNEL_SEQ_BIT, flags) ?
+			 htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
 
 	ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
 }
@@ -478,10 +487,10 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 			__be16 proto)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags) = { };
 	struct ip_tunnel_info *tun_info;
 	const struct ip_tunnel_key *key;
 	int tunnel_hlen;
-	__be16 flags;
 
 	tun_info = skb_tunnel_info(skb);
 	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
@@ -495,14 +504,19 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 		goto err_free_skb;
 
 	/* Push Tunnel header. */
-	if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
+					      tunnel->parms.o_flags)))
 		goto err_free_skb;
 
-	flags = tun_info->key.tun_flags &
-		(TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
+	__set_bit(IP_TUNNEL_CSUM_BIT, flags);
+	__set_bit(IP_TUNNEL_KEY_BIT, flags);
+	__set_bit(IP_TUNNEL_SEQ_BIT, flags);
+	ip_tunnel_flags_and(flags, tun_info->key.tun_flags, flags);
+
 	gre_build_header(skb, tunnel_hlen, flags, proto,
 			 tunnel_id_to_key32(tun_info->key.tun_id),
-			 (flags & TUNNEL_SEQ) ? htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
+			 test_bit(IP_TUNNEL_SEQ_BIT, flags) ?
+			 htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
 
 	ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen);
 
@@ -516,6 +530,7 @@ err_free_skb:
 static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	IP_TUNNEL_DECLARE_FLAGS(flags) = { };
 	struct ip_tunnel_info *tun_info;
 	const struct ip_tunnel_key *key;
 	struct erspan_metadata *md;
@@ -531,7 +546,7 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto err_free_skb;
 
 	key = &tun_info->key;
-	if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT))
+	if (!test_bit(IP_TUNNEL_ERSPAN_OPT_BIT, tun_info->key.tun_flags))
 		goto err_free_skb;
 	if (tun_info->options_len < sizeof(*md))
 		goto err_free_skb;
@@ -584,8 +599,9 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto err_free_skb;
 	}
 
-	gre_build_header(skb, 8, TUNNEL_SEQ,
-			 proto, 0, htonl(atomic_fetch_inc(&tunnel->o_seqno)));
+	__set_bit(IP_TUNNEL_SEQ_BIT, flags);
+	gre_build_header(skb, 8, flags, proto, 0,
+			 htonl(atomic_fetch_inc(&tunnel->o_seqno)));
 
 	ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen);
 
@@ -659,7 +675,8 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 		tnl_params = &tunnel->parms.iph;
 	}
 
-	if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
+					      tunnel->parms.o_flags)))
 		goto free_skb;
 
 	__gre_xmit(skb, dev, tnl_params, skb->protocol);
@@ -701,7 +718,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 	/* Push ERSPAN header */
 	if (tunnel->erspan_ver == 0) {
 		proto = htons(ETH_P_ERSPAN);
-		tunnel->parms.o_flags &= ~TUNNEL_SEQ;
+		__clear_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags);
 	} else if (tunnel->erspan_ver == 1) {
 		erspan_build_header(skb, ntohl(tunnel->parms.o_key),
 				    tunnel->index,
@@ -716,7 +733,7 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 		goto free_skb;
 	}
 
-	tunnel->parms.o_flags &= ~TUNNEL_KEY;
+	__clear_bit(IP_TUNNEL_KEY_BIT, tunnel->parms.o_flags);
 	__gre_xmit(skb, dev, &tunnel->parms.iph, proto);
 	return NETDEV_TX_OK;
 
@@ -739,7 +756,8 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 		return NETDEV_TX_OK;
 	}
 
-	if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
+	if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT,
+					      tunnel->parms.o_flags)))
 		goto free_skb;
 
 	if (skb_cow_head(skb, dev->needed_headroom))
@@ -757,7 +775,6 @@ free_skb:
 static void ipgre_link_update(struct net_device *dev, bool set_mtu)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-	__be16 flags;
 	int len;
 
 	len = tunnel->tun_hlen;
@@ -773,10 +790,9 @@ static void ipgre_link_update(struct net_device *dev, bool set_mtu)
 	if (set_mtu)
 		dev->mtu = max_t(int, dev->mtu - len, 68);
 
-	flags = tunnel->parms.o_flags;
-
-	if (flags & TUNNEL_SEQ ||
-	    (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)) {
+	if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags) ||
+	    (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.o_flags) &&
+	     tunnel->encap.type != TUNNEL_ENCAP_NONE)) {
 		dev->features &= ~NETIF_F_GSO_SOFTWARE;
 		dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
 	} else {
@@ -789,17 +805,25 @@ static int ipgre_tunnel_ctl(struct net_device *dev,
 			    struct ip_tunnel_parm_kern *p,
 			    int cmd)
 {
+	__be16 i_flags, o_flags;
 	int err;
 
+	if (!ip_tunnel_flags_is_be16_compat(p->i_flags) ||
+	    !ip_tunnel_flags_is_be16_compat(p->o_flags))
+		return -EOVERFLOW;
+
+	i_flags = ip_tunnel_flags_to_be16(p->i_flags);
+	o_flags = ip_tunnel_flags_to_be16(p->o_flags);
+
 	if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 		if (p->iph.version != 4 || p->iph.protocol != IPPROTO_GRE ||
 		    p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)) ||
-		    ((p->i_flags | p->o_flags) & (GRE_VERSION | GRE_ROUTING)))
+		    ((i_flags | o_flags) & (GRE_VERSION | GRE_ROUTING)))
 			return -EINVAL;
 	}
 
-	p->i_flags = gre_flags_to_tnl_flags(p->i_flags);
-	p->o_flags = gre_flags_to_tnl_flags(p->o_flags);
+	gre_flags_to_tnl_flags(p->i_flags, i_flags);
+	gre_flags_to_tnl_flags(p->o_flags, o_flags);
 
 	err = ip_tunnel_ctl(dev, p, cmd);
 	if (err)
@@ -808,15 +832,18 @@ static int ipgre_tunnel_ctl(struct net_device *dev,
 	if (cmd == SIOCCHGTUNNEL) {
 		struct ip_tunnel *t = netdev_priv(dev);
 
-		t->parms.i_flags = p->i_flags;
-		t->parms.o_flags = p->o_flags;
+		ip_tunnel_flags_copy(t->parms.i_flags, p->i_flags);
+		ip_tunnel_flags_copy(t->parms.o_flags, p->o_flags);
 
 		if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
 			ipgre_link_update(dev, true);
 	}
 
-	p->i_flags = gre_tnl_flags_to_gre_flags(p->i_flags);
-	p->o_flags = gre_tnl_flags_to_gre_flags(p->o_flags);
+	i_flags = gre_tnl_flags_to_gre_flags(p->i_flags);
+	ip_tunnel_flags_from_be16(p->i_flags, i_flags);
+	o_flags = gre_tnl_flags_to_gre_flags(p->o_flags);
+	ip_tunnel_flags_from_be16(p->o_flags, o_flags);
+
 	return 0;
 }
 
@@ -956,7 +983,6 @@ static void ipgre_tunnel_setup(struct net_device *dev)
 static void __gre_tunnel_init(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel;
-	__be16 flags;
 
 	tunnel = netdev_priv(dev);
 	tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
@@ -968,14 +994,13 @@ static void __gre_tunnel_init(struct net_device *dev)
 	dev->features		|= GRE_FEATURES | NETIF_F_LLTX;
 	dev->hw_features	|= GRE_FEATURES;
 
-	flags = tunnel->parms.o_flags;
-
 	/* TCP offload with GRE SEQ is not supported, nor can we support 2
 	 * levels of outer headers requiring an update.
 	 */
-	if (flags & TUNNEL_SEQ)
+	if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags))
 		return;
-	if (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)
+	if (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.o_flags) &&
+	    tunnel->encap.type != TUNNEL_ENCAP_NONE)
 		return;
 
 	dev->features |= NETIF_F_GSO_SOFTWARE;
@@ -1148,10 +1173,12 @@ static int ipgre_netlink_parms(struct net_device *dev,
 		parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
 
 	if (data[IFLA_GRE_IFLAGS])
-		parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS]));
+		gre_flags_to_tnl_flags(parms->i_flags,
+				       nla_get_be16(data[IFLA_GRE_IFLAGS]));
 
 	if (data[IFLA_GRE_OFLAGS])
-		parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS]));
+		gre_flags_to_tnl_flags(parms->o_flags,
+				       nla_get_be16(data[IFLA_GRE_OFLAGS]));
 
 	if (data[IFLA_GRE_IKEY])
 		parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
@@ -1411,8 +1438,8 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (err < 0)
 		return err;
 
-	t->parms.i_flags = p.i_flags;
-	t->parms.o_flags = p.o_flags;
+	ip_tunnel_flags_copy(t->parms.i_flags, p.i_flags);
+	ip_tunnel_flags_copy(t->parms.o_flags, p.o_flags);
 
 	ipgre_link_update(dev, !tb[IFLA_MTU]);
 
@@ -1440,8 +1467,8 @@ static int erspan_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (err < 0)
 		return err;
 
-	t->parms.i_flags = p.i_flags;
-	t->parms.o_flags = p.o_flags;
+	ip_tunnel_flags_copy(t->parms.i_flags, p.i_flags);
+	ip_tunnel_flags_copy(t->parms.o_flags, p.o_flags);
 
 	return 0;
 }
@@ -1498,7 +1525,9 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
 	struct ip_tunnel *t = netdev_priv(dev);
 	struct ip_tunnel_parm_kern *p = &t->parms;
-	__be16 o_flags = p->o_flags;
+	IP_TUNNEL_DECLARE_FLAGS(o_flags);
+
+	ip_tunnel_flags_copy(o_flags, p->o_flags);
 
 	if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
 	    nla_put_be16(skb, IFLA_GRE_IFLAGS,
@@ -1546,7 +1575,7 @@ static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)
 
 	if (t->erspan_ver <= 2) {
 		if (t->erspan_ver != 0 && !t->collect_md)
-			t->parms.o_flags |= TUNNEL_KEY;
+			__set_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags);
 
 		if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
 			goto nla_put_failure;