Commit dbcefdeb authored by Matt Johnston's avatar Matt Johnston Committed by Jakub Kicinski
Browse files

mctp: emit RTM_NEWADDR and RTM_DELADDR 



Userspace can receive notification of MCTP address changes via
RTNLGRP_MCTP_IFADDR rtnetlink multicast group.

Signed-off-by: default avatarMatt Johnston <matt@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20211220023104.1965509-1-matt@codeconstruct.com.au


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4b430f5c

include/uapi/linux/rtnetlink.h

+2 −0
Original line number Diff line number Diff line
@@ -754,6 +754,8 @@ enum rtnetlink_groups { 
#define RTNLGRP_NEXTHOP		RTNLGRP_NEXTHOP

	RTNLGRP_BRVLAN,

#define RTNLGRP_BRVLAN		RTNLGRP_BRVLAN

	RTNLGRP_MCTP_IFADDR,

#define RTNLGRP_MCTP_IFADDR	RTNLGRP_MCTP_IFADDR

	__RTNLGRP_MAX

};

#define RTNLGRP_MAX	(__RTNLGRP_MAX - 1)

net/mctp/device.c

+48 −5
Original line number Diff line number Diff line
@@ -35,14 +35,24 @@ struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev) 
	return rtnl_dereference(dev->mctp_ptr);

}



static int mctp_fill_addrinfo(struct sk_buff *skb, struct netlink_callback *cb,

			      struct mctp_dev *mdev, mctp_eid_t eid)

static int mctp_addrinfo_size(void)

{

	return NLMSG_ALIGN(sizeof(struct ifaddrmsg))

		+ nla_total_size(1) // IFA_LOCAL

		+ nla_total_size(1) // IFA_ADDRESS

		;

}



/* flag should be NLM_F_MULTI for dump calls */

static int mctp_fill_addrinfo(struct sk_buff *skb,

			      struct mctp_dev *mdev, mctp_eid_t eid,

			      int msg_type, u32 portid, u32 seq, int flag)

{

	struct ifaddrmsg *hdr;

	struct nlmsghdr *nlh;



	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,

			RTM_NEWADDR, sizeof(*hdr), NLM_F_MULTI);

	nlh = nlmsg_put(skb, portid, seq,

			msg_type, sizeof(*hdr), flag);

	if (!nlh)

		return -EMSGSIZE;
@@ -72,10 +82,14 @@ static int mctp_dump_dev_addrinfo(struct mctp_dev *mdev, struct sk_buff *skb, 
				  struct netlink_callback *cb)

{

	struct mctp_dump_cb *mcb = (void *)cb->ctx;

	u32 portid, seq;

	int rc = 0;



	portid = NETLINK_CB(cb->skb).portid;

	seq = cb->nlh->nlmsg_seq;

	for (; mcb->a_idx < mdev->num_addrs; mcb->a_idx++) {

		rc = mctp_fill_addrinfo(skb, cb, mdev, mdev->addrs[mcb->a_idx]);

		rc = mctp_fill_addrinfo(skb, mdev, mdev->addrs[mcb->a_idx],

					RTM_NEWADDR, portid, seq, NLM_F_MULTI);

		if (rc < 0)

			break;

	}
@@ -127,6 +141,32 @@ static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb) 
	return skb->len;

}



static void mctp_addr_notify(struct mctp_dev *mdev, mctp_eid_t eid, int msg_type,

			     struct sk_buff *req_skb, struct nlmsghdr *req_nlh)

{

	u32 portid = NETLINK_CB(req_skb).portid;

	struct net *net = dev_net(mdev->dev);

	struct sk_buff *skb;

	int rc = -ENOBUFS;



	skb = nlmsg_new(mctp_addrinfo_size(), GFP_KERNEL);

	if (!skb)

		goto out;



	rc = mctp_fill_addrinfo(skb, mdev, eid, msg_type,

				portid, req_nlh->nlmsg_seq, 0);

	if (rc < 0) {

		WARN_ON_ONCE(rc == -EMSGSIZE);

		goto out;

	}



	rtnl_notify(skb, net, portid, RTNLGRP_MCTP_IFADDR, req_nlh, GFP_KERNEL);

	return;

out:

	kfree_skb(skb);

	rtnl_set_sk_err(net, RTNLGRP_MCTP_IFADDR, rc);

}



static const struct nla_policy ifa_mctp_policy[IFA_MAX + 1] = {

	[IFA_ADDRESS]		= { .type = NLA_U8 },

	[IFA_LOCAL]		= { .type = NLA_U8 },
@@ -189,6 +229,7 @@ static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, 


	kfree(tmp_addrs);



	mctp_addr_notify(mdev, addr->s_addr, RTM_NEWADDR, skb, nlh);

	mctp_route_add_local(mdev, addr->s_addr);



	return 0;
@@ -244,6 +285,8 @@ static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, 
	mdev->num_addrs--;

	spin_unlock_irqrestore(&mdev->addrs_lock, flags);



	mctp_addr_notify(mdev, addr->s_addr, RTM_DELADDR, skb, nlh);



	return 0;

}