net: Changes to ip_tunnel to support foo-over-udp encapsulation
This patch changes IP tunnel to support (secondary) encapsulation,
Foo-over-UDP. Changes include:
1) Adding tun_hlen as the tunnel header length, encap_hlen as the
encapsulation header length, and hlen becomes the grand total
of these.
2) Added common netlink define to support FOU encapsulation.
3) Routines to perform FOU encapsulation.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index afed1aa..e3a3dc9 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -55,6 +55,7 @@
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
+#include <net/udp.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
@@ -487,6 +488,91 @@
}
EXPORT_SYMBOL_GPL(ip_tunnel_rcv);
+static int ip_encap_hlen(struct ip_tunnel_encap *e)
+{
+ switch (e->type) {
+ case TUNNEL_ENCAP_NONE:
+ return 0;
+ case TUNNEL_ENCAP_FOU:
+ return sizeof(struct udphdr);
+ default:
+ return -EINVAL;
+ }
+}
+
+int ip_tunnel_encap_setup(struct ip_tunnel *t,
+ struct ip_tunnel_encap *ipencap)
+{
+ int hlen;
+
+ memset(&t->encap, 0, sizeof(t->encap));
+
+ hlen = ip_encap_hlen(ipencap);
+ if (hlen < 0)
+ return hlen;
+
+ t->encap.type = ipencap->type;
+ t->encap.sport = ipencap->sport;
+ t->encap.dport = ipencap->dport;
+ t->encap.flags = ipencap->flags;
+
+ t->encap_hlen = hlen;
+ t->hlen = t->encap_hlen + t->tun_hlen;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);
+
+static int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+ size_t hdr_len, u8 *protocol, struct flowi4 *fl4)
+{
+ struct udphdr *uh;
+ __be16 sport;
+ bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
+ int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+
+ skb = iptunnel_handle_offloads(skb, csum, type);
+
+ if (IS_ERR(skb))
+ return PTR_ERR(skb);
+
+ /* Get length and hash before making space in skb */
+
+ sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
+ skb, 0, 0, false);
+
+ skb_push(skb, hdr_len);
+
+ skb_reset_transport_header(skb);
+ uh = udp_hdr(skb);
+
+ uh->dest = e->dport;
+ uh->source = sport;
+ uh->len = htons(skb->len);
+ uh->check = 0;
+ udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
+ fl4->saddr, fl4->daddr, skb->len);
+
+ *protocol = IPPROTO_UDP;
+
+ return 0;
+}
+
+int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
+ u8 *protocol, struct flowi4 *fl4)
+{
+ switch (t->encap.type) {
+ case TUNNEL_ENCAP_NONE:
+ return 0;
+ case TUNNEL_ENCAP_FOU:
+ return fou_build_header(skb, &t->encap, t->encap_hlen,
+ protocol, fl4);
+ default:
+ return -EINVAL;
+ }
+}
+EXPORT_SYMBOL(ip_tunnel_encap);
+
static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
struct rtable *rt, __be16 df)
{
@@ -536,7 +622,7 @@
}
void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
- const struct iphdr *tnl_params, const u8 protocol)
+ const struct iphdr *tnl_params, u8 protocol)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
const struct iphdr *inner_iph;
@@ -617,6 +703,9 @@
init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);
+ if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0)
+ goto tx_error;
+
rt = connected ? tunnel_rtable_get(tunnel, 0, &fl4.saddr) : NULL;
if (!rt) {