Merge branch 'vxlan-headers-and-tx-cleanups'

Jiri Benc says:

====================
vxlan: cleanup headers and tx path

This is first part of vxlan cleanup. It makes vxlan.h better organized and
removes code duplication in the tx path. There's no change in functionality.

This is in preparation for VXLAN-GPE support. Other sets will follow with
cleanup of rx path, modifications of vxlan interface setup and
cleanup/modification of fdb handling. The goal of these patchsets is to
consolidate VXLAN extension handling (right now it's scattered all around
the code) and allow vxlan to operate in L3 mode (i.e. without inner Ethernet
headers).

The full picture (all 30 patches) can be seen at:
https://github.com/jbenc/linux-vxlan/commits/master

Changelog:
v2: added patch 5/6, fixing the udp sum problem spotted by Paolo Abeni
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 69 insertions, 162 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 65439188c582..65f52472a52c 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1684,18 +1684,14 @@ static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, u32 vxflags,
 	gbp->policy_id = htons(md->gbp & VXLAN_GBP_ID_MASK);
 }
 
-#if IS_ENABLED(CONFIG_IPV6)
-static int vxlan6_xmit_skb(struct dst_entry *dst, struct sock *sk,
-			   struct sk_buff *skb,
-			   struct net_device *dev, struct in6_addr *saddr,
-			   struct in6_addr *daddr, __u8 prio, __u8 ttl,
-			   __be16 src_port, __be16 dst_port, __be32 vni,
-			   struct vxlan_metadata *md, bool xnet, u32 vxflags)
+static int vxlan_build_skb(struct sk_buff *skb, struct dst_entry *dst,
+			   int iphdr_len, __be32 vni,
+			   struct vxlan_metadata *md, u32 vxflags,
+			   bool udp_sum)
 {
 	struct vxlanhdr *vxh;
 	int min_headroom;
 	int err;
-	bool udp_sum = !(vxflags & VXLAN_F_UDP_ZERO_CSUM6_TX);
 	int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
 	u16 hdrlen = sizeof(struct vxlanhdr);
 
@@ -1712,93 +1708,8 @@ static int vxlan6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 		}
 	}
 
-	skb_scrub_packet(skb, xnet);
-
 	min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len
-			+ VXLAN_HLEN + sizeof(struct ipv6hdr)
-			+ (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
-
-	/* Need space for new headers (invalidates iph ptr) */
-	err = skb_cow_head(skb, min_headroom);
-	if (unlikely(err)) {
-		kfree_skb(skb);
-		goto err;
-	}
-
-	skb = vlan_hwaccel_push_inside(skb);
-	if (WARN_ON(!skb)) {
-		err = -ENOMEM;
-		goto err;
-	}
-
-	skb = iptunnel_handle_offloads(skb, udp_sum, type);
-	if (IS_ERR(skb)) {
-		err = -EINVAL;
-		goto err;
-	}
-
-	vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));
-	vxh->vx_flags = htonl(VXLAN_HF_VNI);
-	vxh->vx_vni = vni;
-
-	if (type & SKB_GSO_TUNNEL_REMCSUM) {
-		u32 data = (skb_checksum_start_offset(skb) - hdrlen) >>
-			   VXLAN_RCO_SHIFT;
-
-		if (skb->csum_offset == offsetof(struct udphdr, check))
-			data |= VXLAN_RCO_UDP;
-
-		vxh->vx_vni |= htonl(data);
-		vxh->vx_flags |= htonl(VXLAN_HF_RCO);
-
-		if (!skb_is_gso(skb)) {
-			skb->ip_summed = CHECKSUM_NONE;
-			skb->encapsulation = 0;
-		}
-	}
-
-	if (vxflags & VXLAN_F_GBP)
-		vxlan_build_gbp_hdr(vxh, vxflags, md);
-
-	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
-
-	udp_tunnel6_xmit_skb(dst, sk, skb, dev, saddr, daddr, prio,
-			     ttl, src_port, dst_port,
-			     !!(vxflags & VXLAN_F_UDP_ZERO_CSUM6_TX));
-	return 0;
-err:
-	dst_release(dst);
-	return err;
-}
-#endif
-
-static int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
-			  __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
-			  __be16 src_port, __be16 dst_port, __be32 vni,
-			  struct vxlan_metadata *md, bool xnet, u32 vxflags)
-{
-	struct vxlanhdr *vxh;
-	int min_headroom;
-	int err;
-	bool udp_sum = !!(vxflags & VXLAN_F_UDP_CSUM);
-	int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
-	u16 hdrlen = sizeof(struct vxlanhdr);
-
-	if ((vxflags & VXLAN_F_REMCSUM_TX) &&
-	    skb->ip_summed == CHECKSUM_PARTIAL) {
-		int csum_start = skb_checksum_start_offset(skb);
-
-		if (csum_start <= VXLAN_MAX_REMCSUM_START &&
-		    !(csum_start & VXLAN_RCO_SHIFT_MASK) &&
-		    (skb->csum_offset == offsetof(struct udphdr, check) ||
-		     skb->csum_offset == offsetof(struct tcphdr, check))) {
-			udp_sum = false;
-			type |= SKB_GSO_TUNNEL_REMCSUM;
-		}
-	}
-
-	min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
-			+ VXLAN_HLEN + sizeof(struct iphdr)
+			+ VXLAN_HLEN + iphdr_len
 			+ (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
 
 	/* Need space for new headers (invalidates iph ptr) */
@@ -1840,13 +1751,30 @@ static int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *sk
 		vxlan_build_gbp_hdr(vxh, vxflags, md);
 
 	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
-
-	udp_tunnel_xmit_skb(rt, sk, skb, src, dst, tos, ttl, df,
-			    src_port, dst_port, xnet,
-			    !(vxflags & VXLAN_F_UDP_CSUM));
 	return 0;
 }
 
+static struct rtable *vxlan_get_route(struct vxlan_dev *vxlan,
+				      struct sk_buff *skb, int oif, u8 tos,
+				      __be32 daddr, __be32 *saddr)
+{
+	struct rtable *rt = NULL;
+	struct flowi4 fl4;
+
+	memset(&fl4, 0, sizeof(fl4));
+	fl4.flowi4_oif = oif;
+	fl4.flowi4_tos = RT_TOS(tos);
+	fl4.flowi4_mark = skb->mark;
+	fl4.flowi4_proto = IPPROTO_UDP;
+	fl4.daddr = daddr;
+	fl4.saddr = vxlan->cfg.saddr.sin.sin_addr.s_addr;
+
+	rt = ip_route_output_key(vxlan->net, &fl4);
+	if (!IS_ERR(rt))
+		*saddr = fl4.saddr;
+	return rt;
+}
+
 #if IS_ENABLED(CONFIG_IPV6)
 static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 					  struct sk_buff *skb, int oif,
@@ -1928,7 +1856,6 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	struct sock *sk;
 	struct rtable *rt = NULL;
 	const struct iphdr *old_iph;
-	struct flowi4 fl4;
 	union vxlan_addr *dst;
 	union vxlan_addr remote_ip;
 	struct vxlan_metadata _md;
@@ -1939,6 +1866,8 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	__u8 tos, ttl;
 	int err;
 	u32 flags = vxlan->flags;
+	bool udp_sum = false;
+	bool xnet = !net_eq(vxlan->net, dev_net(vxlan->dev));
 
 	info = skb_tunnel_info(skb);
 
@@ -1987,6 +1916,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	if (info) {
 		ttl = info->key.ttl;
 		tos = info->key.tos;
+		udp_sum = !!(info->key.tun_flags & TUNNEL_CSUM);
 
 		if (info->options_len)
 			md = ip_tunnel_info_opts(info);
@@ -1995,6 +1925,8 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	}
 
 	if (dst->sa.sa_family == AF_INET) {
+		__be32 saddr;
+
 		if (!vxlan->vn4_sock)
 			goto drop;
 		sk = vxlan->vn4_sock->sock->sk;
@@ -2002,22 +1934,13 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		if (info) {
 			if (info->key.tun_flags & TUNNEL_DONT_FRAGMENT)
 				df = htons(IP_DF);
-
-			if (info->key.tun_flags & TUNNEL_CSUM)
-				flags |= VXLAN_F_UDP_CSUM;
-			else
-				flags &= ~VXLAN_F_UDP_CSUM;
+		} else {
+			udp_sum = !!(flags & VXLAN_F_UDP_CSUM);
 		}
 
-		memset(&fl4, 0, sizeof(fl4));
-		fl4.flowi4_oif = rdst ? rdst->remote_ifindex : 0;
-		fl4.flowi4_tos = RT_TOS(tos);
-		fl4.flowi4_mark = skb->mark;
-		fl4.flowi4_proto = IPPROTO_UDP;
-		fl4.daddr = dst->sin.sin_addr.s_addr;
-		fl4.saddr = vxlan->cfg.saddr.sin.sin_addr.s_addr;
-
-		rt = ip_route_output_key(vxlan->net, &fl4);
+		rt = vxlan_get_route(vxlan, skb,
+				     rdst ? rdst->remote_ifindex : 0, tos,
+				     dst->sin.sin_addr.s_addr, &saddr);
 		if (IS_ERR(rt)) {
 			netdev_dbg(dev, "no route to %pI4\n",
 				   &dst->sin.sin_addr.s_addr);
@@ -2049,16 +1972,14 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
 		tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
 		ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
-		err = vxlan_xmit_skb(rt, sk, skb, fl4.saddr,
-				     dst->sin.sin_addr.s_addr, tos, ttl, df,
-				     src_port, dst_port, htonl(vni << 8), md,
-				     !net_eq(vxlan->net, dev_net(vxlan->dev)),
-				     flags);
-		if (err < 0) {
-			/* skb is already freed. */
-			skb = NULL;
-			goto rt_tx_error;
-		}
+		err = vxlan_build_skb(skb, &rt->dst, sizeof(struct iphdr),
+				      htonl(vni << 8), md, flags, udp_sum);
+		if (err < 0)
+			goto xmit_tx_error;
+
+		udp_tunnel_xmit_skb(rt, sk, skb, saddr,
+				    dst->sin.sin_addr.s_addr, tos, ttl, df,
+				    src_port, dst_port, xnet, !udp_sum);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		struct dst_entry *ndst;
@@ -2103,18 +2024,20 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 			return;
 		}
 
-		if (info) {
-			if (info->key.tun_flags & TUNNEL_CSUM)
-				flags &= ~VXLAN_F_UDP_ZERO_CSUM6_TX;
-			else
-				flags |= VXLAN_F_UDP_ZERO_CSUM6_TX;
-		}
+		if (!info)
+			udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM6_TX);
 
 		ttl = ttl ? : ip6_dst_hoplimit(ndst);
-		err = vxlan6_xmit_skb(ndst, sk, skb, dev, &saddr, &dst->sin6.sin6_addr,
-				      0, ttl, src_port, dst_port, htonl(vni << 8), md,
-				      !net_eq(vxlan->net, dev_net(vxlan->dev)),
-				      flags);
+		skb_scrub_packet(skb, xnet);
+		err = vxlan_build_skb(skb, ndst, sizeof(struct ipv6hdr),
+				      htonl(vni << 8), md, flags, udp_sum);
+		if (err < 0) {
+			dst_release(ndst);
+			return;
+		}
+		udp_tunnel6_xmit_skb(ndst, sk, skb, dev,
+				     &saddr, &dst->sin6.sin6_addr,
+				     0, ttl, src_port, dst_port, !udp_sum);
 #endif
 	}
 
@@ -2124,6 +2047,9 @@ drop:
 	dev->stats.tx_dropped++;
 	goto tx_free;
 
+xmit_tx_error:
+	/* skb is already freed. */
+	skb = NULL;
 rt_tx_error:
 	ip_rt_put(rt);
 tx_error:
@@ -2390,31 +2316,6 @@ static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
 	return 0;
 }
 
-static int egress_ipv4_tun_info(struct net_device *dev, struct sk_buff *skb,
-				struct ip_tunnel_info *info,
-				__be16 sport, __be16 dport)
-{
-	struct vxlan_dev *vxlan = netdev_priv(dev);
-	struct rtable *rt;
-	struct flowi4 fl4;
-
-	memset(&fl4, 0, sizeof(fl4));
-	fl4.flowi4_tos = RT_TOS(info->key.tos);
-	fl4.flowi4_mark = skb->mark;
-	fl4.flowi4_proto = IPPROTO_UDP;
-	fl4.daddr = info->key.u.ipv4.dst;
-
-	rt = ip_route_output_key(vxlan->net, &fl4);
-	if (IS_ERR(rt))
-		return PTR_ERR(rt);
-	ip_rt_put(rt);
-
-	info->key.u.ipv4.src = fl4.saddr;
-	info->key.tp_src = sport;
-	info->key.tp_dst = dport;
-	return 0;
-}
-
 static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 {
 	struct vxlan_dev *vxlan = netdev_priv(dev);
@@ -2426,9 +2327,16 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 	dport = info->key.tp_dst ? : vxlan->cfg.dst_port;
 
 	if (ip_tunnel_info_af(info) == AF_INET) {
+		struct rtable *rt;
+
 		if (!vxlan->vn4_sock)
 			return -EINVAL;
-		return egress_ipv4_tun_info(dev, skb, info, sport, dport);
+		rt = vxlan_get_route(vxlan, skb, 0, info->key.tos,
+				     info->key.u.ipv4.dst,
+				     &info->key.u.ipv4.src);
+		if (IS_ERR(rt))
+			return PTR_ERR(rt);
+		ip_rt_put(rt);
 	} else {
 #if IS_ENABLED(CONFIG_IPV6)
 		struct dst_entry *ndst;
@@ -2441,13 +2349,12 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 		if (IS_ERR(ndst))
 			return PTR_ERR(ndst);
 		dst_release(ndst);
-
-		info->key.tp_src = sport;
-		info->key.tp_dst = dport;
 #else /* !CONFIG_IPV6 */
 		return -EPFNOSUPPORT;
 #endif
 	}
+	info->key.tp_src = sport;
+	info->key.tp_dst = dport;
 	return 0;
 }