ipv6: sr: add code base for control plane support of SR-IPv6

This patch adds the necessary hooks and structures to provide support
for SR-IPv6 control plane, essentially the Generic Netlink commands
that will be used for userspace control over the Segment Routing
kernel structures.

The genetlink commands provide control over two different structures:
tunnel source and HMAC data. The tunnel source is the source address
that will be used by default when encapsulating packets into an
outer IPv6 header + SRH. If the tunnel source is set to :: then an
address of the outgoing interface will be selected as the source.

The HMAC commands currently just return ENOTSUPP and will be implemented
in a future patch.

Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 55 insertions, 0 deletions

diff --git a/include/linux/seg6_genl.h b/include/linux/seg6_genl.h
new file mode 100644
index 000000000000..d6c3fb4f3734
--- /dev/null
+++ b/include/linux/seg6_genl.h
@@ -0,0 +1,6 @@
+#ifndef _LINUX_SEG6_GENL_H
+#define _LINUX_SEG6_GENL_H
+
+#include <uapi/linux/seg6_genl.h>
+
+#endif
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 10d0848f5b8a..de7745e2edcc 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -85,6 +85,7 @@ struct netns_ipv6 {
 #endif
 	atomic_t		dev_addr_genid;
 	atomic_t		fib6_sernum;
+	struct seg6_pernet_data *seg6_data;
 };
 
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
diff --git a/include/net/seg6.h b/include/net/seg6.h
index 4dd52a7e95f1..7c7b8ed39661 100644
--- a/include/net/seg6.h
+++ b/include/net/seg6.h
@@ -14,6 +14,9 @@
 #ifndef _NET_SEG6_H
 #define _NET_SEG6_H
 
+#include <linux/net.h>
+#include <linux/ipv6.h>
+
 static inline void update_csum_diff4(struct sk_buff *skb, __be32 from,
 				     __be32 to)
 {
@@ -33,4 +36,17 @@ static inline void update_csum_diff16(struct sk_buff *skb, __be32 *from,
 	skb->csum = ~csum_partial((char *)diff, sizeof(diff), ~skb->csum);
 }
 
+struct seg6_pernet_data {
+	struct mutex lock;
+	struct in6_addr __rcu *tun_src;
+};
+
+static inline struct seg6_pernet_data *seg6_pernet(struct net *net)
+{
+	return net->ipv6.seg6_data;
+}
+
+extern int seg6_init(void);
+extern void seg6_exit(void);
+
 #endif
diff --git a/include/uapi/linux/seg6_genl.h b/include/uapi/linux/seg6_genl.h
new file mode 100644
index 000000000000..fcf1c60d7df3
--- /dev/null
+++ b/include/uapi/linux/seg6_genl.h
@@ -0,0 +1,32 @@
+#ifndef _UAPI_LINUX_SEG6_GENL_H
+#define _UAPI_LINUX_SEG6_GENL_H
+
+#define SEG6_GENL_NAME		"SEG6"
+#define SEG6_GENL_VERSION	0x1
+
+enum {
+	SEG6_ATTR_UNSPEC,
+	SEG6_ATTR_DST,
+	SEG6_ATTR_DSTLEN,
+	SEG6_ATTR_HMACKEYID,
+	SEG6_ATTR_SECRET,
+	SEG6_ATTR_SECRETLEN,
+	SEG6_ATTR_ALGID,
+	SEG6_ATTR_HMACINFO,
+	__SEG6_ATTR_MAX,
+};
+
+#define SEG6_ATTR_MAX (__SEG6_ATTR_MAX - 1)
+
+enum {
+	SEG6_CMD_UNSPEC,
+	SEG6_CMD_SETHMAC,
+	SEG6_CMD_DUMPHMAC,
+	SEG6_CMD_SET_TUNSRC,
+	SEG6_CMD_GET_TUNSRC,
+	__SEG6_CMD_MAX,
+};
+
+#define SEG6_CMD_MAX (__SEG6_CMD_MAX - 1)
+
+#endif