Commit d23647fd authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'net-mctp-add-support-for-gateway-routing' 



Jeremy Kerr says:

====================
net: mctp: Add support for gateway routing

This series adds a gateway route type for the MCTP core, allowing
non-local EIDs as the match for a route.

Example setup using the mctp tools:

    mctp route add 9 via mctpi2c0
    mctp neigh add 9 dev mctpi2c0 lladdr 0x1d
    mctp route add 10 gw 9

- will route packets to eid 10 through mctpi2c0, using a dest lladdr
of 0x1d (ie, that of the directly-attached eid 9).

The core change to support this is the introduction of a struct
mctp_dst, which represents the result of a route lookup. Since this
involves a bit of surgery through the routing code, we add a few tests
along the way.

We're introducing an ABI change in the new RTM_{NEW,GET,DEL}ROUTE
netlink formats, with the support for a RTA_GATEWAY attribute. Because
we need a network ID specified to fully-qualify a gateway EID, the
RTA_GATEWAY attribute carries the (net, eid) tuple in full:

    struct mctp_fq_addr {
        unsigned int net;
        mctp_eid_t eid;
    }

Of course, any questions, comments etc are most welcome.

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
====================

Link: https://patch.msgid.link/20250702-dev-forwarding-v5-0-1468191da8a4@codeconstruct.com.au


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents 05cc60ef 48e1736e

include/net/mctp.h

+43 −9
Original line number Diff line number Diff line
@@ -183,8 +183,8 @@ struct mctp_sk_key { 
struct mctp_skb_cb {

	unsigned int	magic;

	unsigned int	net;

	int		ifindex; /* extended/direct addressing if set */

	mctp_eid_t	src;

	/* fields below provide extended addressing for ingress to recvmsg() */

	int		ifindex;

	unsigned char	halen;

	unsigned char	haddr[MAX_ADDR_LEN];

};
@@ -222,6 +222,8 @@ struct mctp_flow { 
	struct mctp_sk_key *key;

};



struct mctp_dst;



/* Route definition.

 *

 * These are held in the pernet->mctp.routes list, with RCU protection for
@@ -229,16 +231,25 @@ struct mctp_flow { 
 * dropped on NETDEV_UNREGISTER events.

 *

 * Updates to the route table are performed under rtnl; all reads under RCU,

 * so routes cannot be referenced over a RCU grace period. Specifically: A

 * caller cannot block between mctp_route_lookup and mctp_route_release()

 * so routes cannot be referenced over a RCU grace period.

 */

struct mctp_route {

	mctp_eid_t		min, max;



	unsigned char		type;



	unsigned int		mtu;



	enum {

		MCTP_ROUTE_DIRECT,

		MCTP_ROUTE_GATEWAY,

	} dst_type;

	union {

		struct mctp_dev	*dev;

	int			(*output)(struct mctp_route *route,

		struct mctp_fq_addr gateway;

	};



	int			(*output)(struct mctp_dst *dst,

					  struct sk_buff *skb);



	struct list_head	list;
@@ -246,12 +257,35 @@ struct mctp_route { 
	struct rcu_head		rcu;

};



/* Route lookup result: dst. Represents the results of a routing decision,

 * but is only held over the individual routing operation.

 *

 * Will typically be stored on the caller stack, and must be released after

 * usage.

 */

struct mctp_dst {

	struct mctp_dev *dev;

	unsigned int mtu;

	mctp_eid_t nexthop;



	/* set for direct addressing */

	unsigned char halen;

	unsigned char haddr[MAX_ADDR_LEN];



	int (*output)(struct mctp_dst *dst, struct sk_buff *skb);

};



int mctp_dst_from_extaddr(struct mctp_dst *dst, struct net *net, int ifindex,

			  unsigned char halen, const unsigned char *haddr);



/* route interfaces */

struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,

				     mctp_eid_t daddr);

int mctp_route_lookup(struct net *net, unsigned int dnet,

		      mctp_eid_t daddr, struct mctp_dst *dst);



void mctp_dst_release(struct mctp_dst *dst);



/* always takes ownership of skb */

int mctp_local_output(struct sock *sk, struct mctp_route *rt,

int mctp_local_output(struct sock *sk, struct mctp_dst *dst,

		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);



void mctp_key_unref(struct mctp_sk_key *key);

include/uapi/linux/mctp.h

+8 −0
Original line number Diff line number Diff line
@@ -37,6 +37,14 @@ struct sockaddr_mctp_ext { 
	__u8			smctp_haddr[MAX_ADDR_LEN];

};



/* A "fully qualified" MCTP address, which includes the system-local network ID,

 * required to uniquely resolve a routable EID.

 */

struct mctp_fq_addr {

	unsigned int	net;

	mctp_eid_t	eid;

};



#define MCTP_NET_ANY		0x0



#define MCTP_ADDR_NULL		0x00

net/mctp/af_mctp.c

+26 −40
Original line number Diff line number Diff line
@@ -97,8 +97,8 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	struct sock *sk = sock->sk;

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

	struct mctp_skb_cb *cb;

	struct mctp_route *rt;

	struct sk_buff *skb = NULL;

	struct mctp_dst dst;

	int hlen;



	if (addr) {
@@ -133,34 +133,30 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	if (msk->addr_ext && addrlen >= sizeof(struct sockaddr_mctp_ext)) {

		DECLARE_SOCKADDR(struct sockaddr_mctp_ext *,

				 extaddr, msg->msg_name);

		struct net_device *dev;



		rc = -EINVAL;

		rcu_read_lock();

		dev = dev_get_by_index_rcu(sock_net(sk), extaddr->smctp_ifindex);

		/* check for correct halen */

		if (dev && extaddr->smctp_halen == dev->addr_len) {

			hlen = LL_RESERVED_SPACE(dev) + sizeof(struct mctp_hdr);

			rc = 0;

		}

		rcu_read_unlock();

		if (!mctp_sockaddr_ext_is_ok(extaddr))

			return -EINVAL;



		rc = mctp_dst_from_extaddr(&dst, sock_net(sk),

					   extaddr->smctp_ifindex,

					   extaddr->smctp_halen,

					   extaddr->smctp_haddr);

		if (rc)

			goto err_free;

		rt = NULL;

			return rc;



	} else {

		rt = mctp_route_lookup(sock_net(sk), addr->smctp_network,

				       addr->smctp_addr.s_addr);

		if (!rt) {

			rc = -EHOSTUNREACH;

			goto err_free;

		}

		hlen = LL_RESERVED_SPACE(rt->dev->dev) + sizeof(struct mctp_hdr);

		rc = mctp_route_lookup(sock_net(sk), addr->smctp_network,

				       addr->smctp_addr.s_addr, &dst);

		if (rc)

			return rc;

	}



	hlen = LL_RESERVED_SPACE(dst.dev->dev) + sizeof(struct mctp_hdr);



	skb = sock_alloc_send_skb(sk, hlen + 1 + len,

				  msg->msg_flags & MSG_DONTWAIT, &rc);

	if (!skb)

		return rc;

		goto err_release_dst;



	skb_reserve(skb, hlen);
@@ -175,30 +171,16 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	cb = __mctp_cb(skb);

	cb->net = addr->smctp_network;



	if (!rt) {

		/* fill extended address in cb */

		DECLARE_SOCKADDR(struct sockaddr_mctp_ext *,

				 extaddr, msg->msg_name);



		if (!mctp_sockaddr_ext_is_ok(extaddr) ||

		    extaddr->smctp_halen > sizeof(cb->haddr)) {

			rc = -EINVAL;

			goto err_free;

		}



		cb->ifindex = extaddr->smctp_ifindex;

		/* smctp_halen is checked above */

		cb->halen = extaddr->smctp_halen;

		memcpy(cb->haddr, extaddr->smctp_haddr, cb->halen);

	}



	rc = mctp_local_output(sk, rt, skb, addr->smctp_addr.s_addr,

	rc = mctp_local_output(sk, &dst, skb, addr->smctp_addr.s_addr,

			       addr->smctp_tag);



	mctp_dst_release(&dst);

	return rc ? : len;



err_free:

	kfree_skb(skb);

err_release_dst:

	mctp_dst_release(&dst);

	return rc;

}
@@ -793,3 +775,7 @@ MODULE_DESCRIPTION("MCTP core"); 
MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");



MODULE_ALIAS_NETPROTO(PF_MCTP);



#if IS_ENABLED(CONFIG_MCTP_TEST)

#include "test/sock-test.c"

#endif

net/mctp/route.c

+385 −189

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net/mctp/test/route-test.c

+395 −217

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