Commit 1aeed732 authored by Matt Johnston's avatar Matt Johnston Committed by Paolo Abeni
Browse files

net: mctp: Use hashtable for binds 



Ensure that a specific EID (remote or local) bind will match in
preference to a MCTP_ADDR_ANY bind.

This adds infrastructure for binding a socket to receive messages from a
specific remote peer address, a future commit will expose an API for
this.

Signed-off-by: default avatarMatt Johnston <matt@codeconstruct.com.au>
Link: https://patch.msgid.link/20250710-mctp-bind-v4-5-8ec2f6460c56@codeconstruct.com.au


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 4ec4b7fc

include/net/netns/mctp.h

+16 −4
Original line number Diff line number Diff line
@@ -6,19 +6,25 @@ 
#ifndef __NETNS_MCTP_H__

#define __NETNS_MCTP_H__



#include <linux/hash.h>

#include <linux/hashtable.h>

#include <linux/mutex.h>

#include <linux/types.h>



#define MCTP_BINDS_BITS 7



struct netns_mctp {

	/* Only updated under RTNL, entries freed via RCU */

	struct list_head routes;



	/* Bound sockets: list of sockets bound by type.

	 * This list is updated from non-atomic contexts (under bind_lock),

	 * and read (under rcu) in packet rx

	/* Bound sockets: hash table of sockets, keyed by

	 * (type, src_eid, dest_eid).

	 * Specific src_eid/dest_eid entries also have an entry for

	 * MCTP_ADDR_ANY. This list is updated from non-atomic contexts

	 * (under bind_lock), and read (under rcu) in packet rx.

	 */

	struct mutex bind_lock;

	struct hlist_head binds;

	DECLARE_HASHTABLE(binds, MCTP_BINDS_BITS);



	/* tag allocations. This list is read and updated from atomic contexts,

	 * but elements are free()ed after a RCU grace-period
@@ -34,4 +40,10 @@ struct netns_mctp { 
	struct list_head neighbours;

};



static inline u32 mctp_bind_hash(u8 type, u8 local_addr, u8 peer_addr)

{

	return hash_32(type | (u32)local_addr << 8 | (u32)peer_addr << 16,

		       MCTP_BINDS_BITS);

}



#endif /* __NETNS_MCTP_H__ */

net/mctp/af_mctp.c

+7 −4
Original line number Diff line number Diff line
@@ -626,17 +626,17 @@ static int mctp_sk_hash(struct sock *sk) 
	struct net *net = sock_net(sk);

	struct sock *existing;

	struct mctp_sock *msk;

	u32 hash;

	int rc;



	msk = container_of(sk, struct mctp_sock, sk);



	/* Bind lookup runs under RCU, remain live during that. */

	sock_set_flag(sk, SOCK_RCU_FREE);

	hash = mctp_bind_hash(msk->bind_type, msk->bind_addr, MCTP_ADDR_ANY);



	mutex_lock(&net->mctp.bind_lock);



	/* Prevent duplicate binds. */

	sk_for_each(existing, &net->mctp.binds) {

	sk_for_each(existing, &net->mctp.binds[hash]) {

		struct mctp_sock *mex =

			container_of(existing, struct mctp_sock, sk);
@@ -648,7 +648,10 @@ static int mctp_sk_hash(struct sock *sk) 
		}

	}



	sk_add_node_rcu(sk, &net->mctp.binds);

	/* Bind lookup runs under RCU, remain live during that. */

	sock_set_flag(sk, SOCK_RCU_FREE);



	sk_add_node_rcu(sk, &net->mctp.binds[hash]);

	rc = 0;



out:

net/mctp/route.c

+61 −14
Original line number Diff line number Diff line
@@ -40,33 +40,32 @@ static int mctp_dst_discard(struct mctp_dst *dst, struct sk_buff *skb) 
	return 0;

}



static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb)

static struct mctp_sock *mctp_lookup_bind_details(struct net *net,

						  struct sk_buff *skb,

						  u8 type, u8 dest,

						  u8 src, bool allow_net_any)

{

	struct mctp_skb_cb *cb = mctp_cb(skb);

	struct mctp_hdr *mh;

	struct sock *sk;

	u8 type;



	WARN_ON(!rcu_read_lock_held());



	/* TODO: look up in skb->cb? */

	mh = mctp_hdr(skb);

	u8 hash;



	if (!skb_headlen(skb))

		return NULL;

	WARN_ON_ONCE(!rcu_read_lock_held());



	type = (*(u8 *)skb->data) & 0x7f;

	hash = mctp_bind_hash(type, dest, src);



	sk_for_each_rcu(sk, &net->mctp.binds) {

	sk_for_each_rcu(sk, &net->mctp.binds[hash]) {

		struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);



		if (!allow_net_any && msk->bind_net == MCTP_NET_ANY)

			continue;



		if (msk->bind_net != MCTP_NET_ANY && msk->bind_net != cb->net)

			continue;



		if (msk->bind_type != type)

			continue;



		if (!mctp_address_matches(msk->bind_addr, mh->dest))

		if (!mctp_address_matches(msk->bind_addr, dest))

			continue;



		return msk;
@@ -75,6 +74,54 @@ static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb) 
	return NULL;

}



static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb)

{

	struct mctp_sock *msk;

	struct mctp_hdr *mh;

	u8 type;



	/* TODO: look up in skb->cb? */

	mh = mctp_hdr(skb);



	if (!skb_headlen(skb))

		return NULL;



	type = (*(u8 *)skb->data) & 0x7f;



	/* Look for binds in order of widening scope. A given destination or

	 * source address also implies matching on a particular network.

	 *

	 * - Matching destination and source

	 * - Matching destination

	 * - Matching source

	 * - Matching network, any address

	 * - Any network or address

	 */



	msk = mctp_lookup_bind_details(net, skb, type, mh->dest, mh->src,

				       false);

	if (msk)

		return msk;

	msk = mctp_lookup_bind_details(net, skb, type, MCTP_ADDR_ANY, mh->src,

				       false);

	if (msk)

		return msk;

	msk = mctp_lookup_bind_details(net, skb, type, mh->dest, MCTP_ADDR_ANY,

				       false);

	if (msk)

		return msk;

	msk = mctp_lookup_bind_details(net, skb, type, MCTP_ADDR_ANY,

				       MCTP_ADDR_ANY, false);

	if (msk)

		return msk;

	msk = mctp_lookup_bind_details(net, skb, type, MCTP_ADDR_ANY,

				       MCTP_ADDR_ANY, true);

	if (msk)

		return msk;



	return NULL;

}



/* A note on the key allocations.

 *

 * struct net->mctp.keys contains our set of currently-allocated keys for
@@ -1671,7 +1718,7 @@ static int __net_init mctp_routes_net_init(struct net *net) 
	struct netns_mctp *ns = &net->mctp;



	INIT_LIST_HEAD(&ns->routes);

	INIT_HLIST_HEAD(&ns->binds);

	hash_init(ns->binds);

	mutex_init(&ns->bind_lock);

	INIT_HLIST_HEAD(&ns->keys);

	spin_lock_init(&ns->keys_lock);