vxlan: use generic function for tunnel IPv4 route lookup

The route lookup can be done now via generic function
udp_tunnel_dst_lookup() to replace the custom implementations in
vxlan_get_route().

Note that this patch only touches IPv4, while IPv6 still uses
vxlan6_get_route(). After IPv6 route lookup gets converted as well,
vxlan_xmit_one() can be simplified by removing local variables that
will be passed via "struct ip_tunnel_key", such as remote_ip,
local_ip, flow_flags, label.

Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index ece377b1b6bde982581b558fa1d3c1d0050afb66..6f7d45e3cfa2e84f8c19ff5f31b7dc7176a38cbf 100644 (file)
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2215,57 +2215,6 @@ static int vxlan_build_skb(struct sk_buff *skb, struct dst_entry *dst,
        return 0;
 }
 
-static struct rtable *vxlan_get_route(struct vxlan_dev *vxlan, struct net_device *dev,
-                                     struct vxlan_sock *sock4,
-                                     struct sk_buff *skb, int oif, u8 tos,
-                                     __be32 daddr, __be32 *saddr, __be16 dport, __be16 sport,
-                                     __u8 flow_flags, struct dst_cache *dst_cache,
-                                     const struct ip_tunnel_info *info)
-{
-       bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
-       struct rtable *rt = NULL;
-       struct flowi4 fl4;
-
-       if (!sock4)
-               return ERR_PTR(-EIO);
-
-       if (tos && !info)
-               use_cache = false;
-       if (use_cache) {
-               rt = dst_cache_get_ip4(dst_cache, saddr);
-               if (rt)
-                       return rt;
-       }
-
-       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 = *saddr;
-       fl4.fl4_dport = dport;
-       fl4.fl4_sport = sport;
-       fl4.flowi4_flags = flow_flags;
-
-       rt = ip_route_output_key(vxlan->net, &fl4);
-       if (!IS_ERR(rt)) {
-               if (rt->dst.dev == dev) {
-                       netdev_dbg(dev, "circular route to %pI4\n", &daddr);
-                       ip_rt_put(rt);
-                       return ERR_PTR(-ELOOP);
-               }
-
-               *saddr = fl4.saddr;
-               if (use_cache)
-                       dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
-       } else {
-               netdev_dbg(dev, "no route to %pI4\n", &daddr);
-               return ERR_PTR(-ENETUNREACH);
-       }
-       return rt;
-}
-
 #if IS_ENABLED(CONFIG_IPV6)
 static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
                                          struct net_device *dev,
@@ -2418,30 +2367,38 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 {
        struct dst_cache *dst_cache;
        struct ip_tunnel_info *info;
+       struct ip_tunnel_key *pkey;
+       struct ip_tunnel_key key;
        struct vxlan_dev *vxlan = netdev_priv(dev);
        const struct iphdr *old_iph = ip_hdr(skb);
        union vxlan_addr *dst;
-       union vxlan_addr remote_ip, local_ip;
+       union vxlan_addr remote_ip;
        struct vxlan_metadata _md;
        struct vxlan_metadata *md = &_md;
        unsigned int pkt_len = skb->len;
        __be16 src_port = 0, dst_port;
        struct dst_entry *ndst = NULL;
-       __u8 tos, ttl, flow_flags = 0;
+       __u8 tos, ttl;
        int ifindex;
        int err;
        u32 flags = vxlan->cfg.flags;
+       bool use_cache;
        bool udp_sum = false;
        bool xnet = !net_eq(vxlan->net, dev_net(vxlan->dev));
        __be32 vni = 0;
 #if IS_ENABLED(CONFIG_IPV6)
+       union vxlan_addr local_ip;
        __be32 label;
 #endif
 
        info = skb_tunnel_info(skb);
+       use_cache = ip_tunnel_dst_cache_usable(skb, info);
 
        if (rdst) {
                dst = &rdst->remote_ip;
+               memset(&key, 0, sizeof(key));
+               pkey = &key;
+
                if (vxlan_addr_any(dst)) {
                        if (did_rsc) {
                                /* short-circuited back to local bridge */
@@ -2455,7 +2412,15 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                dst_port = rdst->remote_port ? rdst->remote_port : vxlan->cfg.dst_port;
                vni = (rdst->remote_vni) ? : default_vni;
                ifindex = rdst->remote_ifindex;
-               local_ip = vxlan->cfg.saddr;
+
+               if (dst->sa.sa_family == AF_INET) {
+                       key.u.ipv4.src = vxlan->cfg.saddr.sin.sin_addr.s_addr;
+                       key.u.ipv4.dst = rdst->remote_ip.sin.sin_addr.s_addr;
+               } else {
+                       key.u.ipv6.src = vxlan->cfg.saddr.sin6.sin6_addr;
+                       key.u.ipv6.dst = rdst->remote_ip.sin6.sin6_addr;
+               }
+
                dst_cache = &rdst->dst_cache;
                md->gbp = skb->mark;
                if (flags & VXLAN_F_TTL_INHERIT) {
@@ -2469,12 +2434,15 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                tos = vxlan->cfg.tos;
                if (tos == 1)
                        tos = ip_tunnel_get_dsfield(old_iph, skb);
+               if (tos && !info)
+                       use_cache = false;
 
                if (dst->sa.sa_family == AF_INET)
                        udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM_TX);
                else
                        udp_sum = !(flags & VXLAN_F_UDP_ZERO_CSUM6_TX);
 #if IS_ENABLED(CONFIG_IPV6)
+               local_ip = vxlan->cfg.saddr;
                label = vxlan->cfg.label;
 #endif
        } else {
@@ -2486,14 +2454,15 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                remote_ip.sa.sa_family = ip_tunnel_info_af(info);
                if (remote_ip.sa.sa_family == AF_INET) {
                        remote_ip.sin.sin_addr.s_addr = info->key.u.ipv4.dst;
-                       local_ip.sin.sin_addr.s_addr = info->key.u.ipv4.src;
                } else {
                        remote_ip.sin6.sin6_addr = info->key.u.ipv6.dst;
+#if IS_ENABLED(CONFIG_IPV6)
                        local_ip.sin6.sin6_addr = info->key.u.ipv6.src;
+#endif
                }
                dst = &remote_ip;
+               pkey = &info->key;
                dst_port = info->key.tp_dst ? : vxlan->cfg.dst_port;
-               flow_flags = info->key.flow_flags;
                vni = tunnel_id_to_key32(info->key.tun_id);
                ifindex = 0;
                dst_cache = &info->dst_cache;
@@ -2517,15 +2486,14 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
                struct rtable *rt;
                __be16 df = 0;
+               __be32 saddr;
 
                if (!ifindex)
                        ifindex = sock4->sock->sk->sk_bound_dev_if;
 
-               rt = vxlan_get_route(vxlan, dev, sock4, skb, ifindex, tos,
-                                    dst->sin.sin_addr.s_addr,
-                                    &local_ip.sin.sin_addr.s_addr,
-                                    dst_port, src_port, flow_flags,
-                                    dst_cache, info);
+               rt = udp_tunnel_dst_lookup(skb, dev, vxlan->net, ifindex,
+                                          &saddr, pkey, src_port, dst_port,
+                                          tos, use_cache ? dst_cache : NULL);
                if (IS_ERR(rt)) {
                        err = PTR_ERR(rt);
                        goto tx_error;
@@ -2561,16 +2529,13 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                } else if (err) {
                        if (info) {
                                struct ip_tunnel_info *unclone;
-                               struct in_addr src, dst;
 
                                unclone = skb_tunnel_info_unclone(skb);
                                if (unlikely(!unclone))
                                        goto tx_error;
 
-                               src = remote_ip.sin.sin_addr;
-                               dst = local_ip.sin.sin_addr;
-                               unclone->key.u.ipv4.src = src.s_addr;
-                               unclone->key.u.ipv4.dst = dst.s_addr;
+                               unclone->key.u.ipv4.src = pkey->u.ipv4.dst;
+                               unclone->key.u.ipv4.dst = saddr;
                        }
                        vxlan_encap_bypass(skb, vxlan, vxlan, vni, false);
                        dst_release(ndst);
@@ -2584,8 +2549,8 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                if (err < 0)
                        goto tx_error;
 
-               udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, local_ip.sin.sin_addr.s_addr,
-                                   dst->sin.sin_addr.s_addr, tos, ttl, df,
+               udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, saddr,
+                                   pkey->u.ipv4.dst, tos, ttl, df,
                                    src_port, dst_port, xnet, !udp_sum);
 #if IS_ENABLED(CONFIG_IPV6)
        } else {
@@ -3286,11 +3251,14 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
                struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
                struct rtable *rt;
 
-               rt = vxlan_get_route(vxlan, dev, sock4, skb, 0, info->key.tos,
-                                    info->key.u.ipv4.dst,
-                                    &info->key.u.ipv4.src, dport, sport,
-                                    info->key.flow_flags, &info->dst_cache,
-                                    info);
+               if (!sock4)
+                       return -EIO;
+
+               rt = udp_tunnel_dst_lookup(skb, dev, vxlan->net, 0,
+                                          &info->key.u.ipv4.src,
+                                          &info->key,
+                                          sport, dport, info->key.tos,
+                                          &info->dst_cache);
                if (IS_ERR(rt))
                        return PTR_ERR(rt);
                ip_rt_put(rt);