Merge branch 'MCTP-tag-control-interface'

Jeremy Kerr says:

====================
MCTP tag control interface

This series implements a small interface for userspace-controlled
message tag allocation for the MCTP protocol. Rather than leaving the
kernel to allocate per-message tag values, userspace can explicitly
allocate (and release) message tags through two new ioctls:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG.

In order to do this, we first introduce some minor changes to the tag
handling, including a couple of new tests for the route input paths.

As always, any comments/queries/etc are most welcome.

v2:
 - make mctp_lookup_prealloc_tag static
 - minor checkpatch formatting fixes
====================

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

3 files changed, 37 insertions, 2 deletions

diff --git a/include/net/mctp.h b/include/net/mctp.h
index 7e35ec79b909..e80a4baf8379 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -45,6 +45,11 @@ static inline bool mctp_address_ok(mctp_eid_t eid)
 	return eid >= 8 && eid < 255;
 }
 
+static inline bool mctp_address_matches(mctp_eid_t match, mctp_eid_t eid)
+{
+	return match == eid || match == MCTP_ADDR_ANY;
+}
+
 static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb)
 {
 	return (struct mctp_hdr *)skb_network_header(skb);
@@ -121,7 +126,7 @@ struct mctp_sock {
  */
 struct mctp_sk_key {
 	mctp_eid_t	peer_addr;
-	mctp_eid_t	local_addr;
+	mctp_eid_t	local_addr; /* MCTP_ADDR_ANY for local owned tags */
 	__u8		tag; /* incoming tag match; invert TO for local */
 
 	/* we hold a ref to sk when set */
@@ -158,6 +163,12 @@ struct mctp_sk_key {
 	 */
 	unsigned long	dev_flow_state;
 	struct mctp_dev	*dev;
+
+	/* a tag allocated with SIOCMCTPALLOCTAG ioctl will not expire
+	 * automatically on timeout or response, instead SIOCMCTPDROPTAG
+	 * is used.
+	 */
+	bool		manual_alloc;
 };
 
 struct mctp_skb_cb {
@@ -234,6 +245,9 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
 		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);
 
 void mctp_key_unref(struct mctp_sk_key *key);
+struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
+					 mctp_eid_t daddr, mctp_eid_t saddr,
+					 bool manual, u8 *tagp);
 
 /* routing <--> device interface */
 unsigned int mctp_default_net(struct net *net);
diff --git a/include/trace/events/mctp.h b/include/trace/events/mctp.h
index 175b057c507f..165cf25f77a7 100644
--- a/include/trace/events/mctp.h
+++ b/include/trace/events/mctp.h
@@ -15,6 +15,7 @@ enum {
 	MCTP_TRACE_KEY_REPLIED,
 	MCTP_TRACE_KEY_INVALIDATED,
 	MCTP_TRACE_KEY_CLOSED,
+	MCTP_TRACE_KEY_DROPPED,
 };
 #endif /* __TRACE_MCTP_ENUMS */
 
@@ -22,6 +23,7 @@ TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_TIMEOUT);
 TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_REPLIED);
 TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_INVALIDATED);
 TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_CLOSED);
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_DROPPED);
 
 TRACE_EVENT(mctp_key_acquire,
 	TP_PROTO(const struct mctp_sk_key *key),
@@ -66,7 +68,8 @@ TRACE_EVENT(mctp_key_release,
 				 { MCTP_TRACE_KEY_TIMEOUT, "timeout" },
 				 { MCTP_TRACE_KEY_REPLIED, "replied" },
 				 { MCTP_TRACE_KEY_INVALIDATED, "invalidated" },
-				 { MCTP_TRACE_KEY_CLOSED, "closed" })
+				 { MCTP_TRACE_KEY_CLOSED, "closed" },
+				 { MCTP_TRACE_KEY_DROPPED, "dropped" })
 	)
 );
 
diff --git a/include/uapi/linux/mctp.h b/include/uapi/linux/mctp.h
index 07b0318716fc..154ab56651f1 100644
--- a/include/uapi/linux/mctp.h
+++ b/include/uapi/linux/mctp.h
@@ -44,7 +44,25 @@ struct sockaddr_mctp_ext {
 
 #define MCTP_TAG_MASK		0x07
 #define MCTP_TAG_OWNER		0x08
+#define MCTP_TAG_PREALLOC	0x10
 
 #define MCTP_OPT_ADDR_EXT	1
 
+#define SIOCMCTPALLOCTAG	(SIOCPROTOPRIVATE + 0)
+#define SIOCMCTPDROPTAG		(SIOCPROTOPRIVATE + 1)
+
+struct mctp_ioc_tag_ctl {
+	mctp_eid_t	peer_addr;
+
+	/* For SIOCMCTPALLOCTAG: must be passed as zero, kernel will
+	 * populate with the allocated tag value. Returned tag value will
+	 * always have TO and PREALLOC set.
+	 *
+	 * For SIOCMCTPDROPTAG: userspace provides tag value to drop, from
+	 * a prior SIOCMCTPALLOCTAG call (and so must have TO and PREALLOC set).
+	 */
+	__u8		tag;
+	__u16		flags;
+};
+
 #endif /* __UAPI_MCTP_H */