Commit 3cbab892 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'inet-implement-lockless-rtm_getnetconf-ops' 

Eric Dumazet says:

====================
inet: implement lockless RTM_GETNETCONF ops

This series removes RTNL use for RTM_GETNETCONF operations on AF_INET.

- Annotate data-races to avoid possible KCSAN splats.

- "ip -4 netconf show dev XXX" can be implemented without RTNL [1]

- "ip -4 netconf" dumps can be implemented using RCU instead of RTNL [1]

[1] This only refers to RTM_GETNETCONF operation, "ip" command
    also uses RTM_GETLINK dumps which are using RTNL at this moment.
====================

Link: https://lore.kernel.org/r/20240227092411.2315725-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents e83ddcea 16748707

include/linux/inetdevice.h

+8 −6
Original line number Diff line number Diff line
@@ -53,13 +53,15 @@ struct in_device { 
};



#define IPV4_DEVCONF(cnf, attr) ((cnf).data[IPV4_DEVCONF_ ## attr - 1])

#define IPV4_DEVCONF_RO(cnf, attr) READ_ONCE(IPV4_DEVCONF(cnf, attr))

#define IPV4_DEVCONF_ALL(net, attr) \

	IPV4_DEVCONF((*(net)->ipv4.devconf_all), attr)

#define IPV4_DEVCONF_ALL_RO(net, attr) READ_ONCE(IPV4_DEVCONF_ALL(net, attr))



static inline int ipv4_devconf_get(struct in_device *in_dev, int index)

static inline int ipv4_devconf_get(const struct in_device *in_dev, int index)

{

	index--;

	return in_dev->cnf.data[index];

	return READ_ONCE(in_dev->cnf.data[index]);

}



static inline void ipv4_devconf_set(struct in_device *in_dev, int index,
@@ -67,7 +69,7 @@ static inline void ipv4_devconf_set(struct in_device *in_dev, int index, 
{

	index--;

	set_bit(index, in_dev->cnf.state);

	in_dev->cnf.data[index] = val;

	WRITE_ONCE(in_dev->cnf.data[index], val);

}



static inline void ipv4_devconf_setall(struct in_device *in_dev)
@@ -81,18 +83,18 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev) 
	ipv4_devconf_set((in_dev), IPV4_DEVCONF_ ## attr, (val))



#define IN_DEV_ANDCONF(in_dev, attr) \

	(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr) && \

	(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), attr) && \

	 IN_DEV_CONF_GET((in_dev), attr))



#define IN_DEV_NET_ORCONF(in_dev, net, attr) \

	(IPV4_DEVCONF_ALL(net, attr) || \

	(IPV4_DEVCONF_ALL_RO(net, attr) || \

	 IN_DEV_CONF_GET((in_dev), attr))



#define IN_DEV_ORCONF(in_dev, attr) \

	IN_DEV_NET_ORCONF(in_dev, dev_net(in_dev->dev), attr)



#define IN_DEV_MAXCONF(in_dev, attr) \

	(max(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr), \

	(max(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), attr), \

	     IN_DEV_CONF_GET((in_dev), attr)))



#define IN_DEV_FORWARD(in_dev)		IN_DEV_CONF_GET((in_dev), FORWARDING)

net/ipv4/devinet.c

+68 −79
Original line number Diff line number Diff line
@@ -1982,7 +1982,7 @@ static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev, 
		return -EMSGSIZE;



	for (i = 0; i < IPV4_DEVCONF_MAX; i++)

		((u32 *) nla_data(nla))[i] = in_dev->cnf.data[i];

		((u32 *) nla_data(nla))[i] = READ_ONCE(in_dev->cnf.data[i]);



	return 0;

}
@@ -2068,9 +2068,9 @@ static int inet_netconf_msgsize_devconf(int type) 
}



static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,

				     struct ipv4_devconf *devconf, u32 portid,

				     u32 seq, int event, unsigned int flags,

				     int type)

				     const struct ipv4_devconf *devconf,

				     u32 portid, u32 seq, int event,

				     unsigned int flags, int type)

{

	struct nlmsghdr  *nlh;

	struct netconfmsg *ncm;
@@ -2095,27 +2095,28 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex, 


	if ((all || type == NETCONFA_FORWARDING) &&

	    nla_put_s32(skb, NETCONFA_FORWARDING,

			IPV4_DEVCONF(*devconf, FORWARDING)) < 0)

			IPV4_DEVCONF_RO(*devconf, FORWARDING)) < 0)

		goto nla_put_failure;

	if ((all || type == NETCONFA_RP_FILTER) &&

	    nla_put_s32(skb, NETCONFA_RP_FILTER,

			IPV4_DEVCONF(*devconf, RP_FILTER)) < 0)

			IPV4_DEVCONF_RO(*devconf, RP_FILTER)) < 0)

		goto nla_put_failure;

	if ((all || type == NETCONFA_MC_FORWARDING) &&

	    nla_put_s32(skb, NETCONFA_MC_FORWARDING,

			IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0)

			IPV4_DEVCONF_RO(*devconf, MC_FORWARDING)) < 0)

		goto nla_put_failure;

	if ((all || type == NETCONFA_BC_FORWARDING) &&

	    nla_put_s32(skb, NETCONFA_BC_FORWARDING,

			IPV4_DEVCONF(*devconf, BC_FORWARDING)) < 0)

			IPV4_DEVCONF_RO(*devconf, BC_FORWARDING)) < 0)

		goto nla_put_failure;

	if ((all || type == NETCONFA_PROXY_NEIGH) &&

	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH,

			IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0)

			IPV4_DEVCONF_RO(*devconf, PROXY_ARP)) < 0)

		goto nla_put_failure;

	if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&

	    nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,

			IPV4_DEVCONF(*devconf, IGNORE_ROUTES_WITH_LINKDOWN)) < 0)

			IPV4_DEVCONF_RO(*devconf,

					IGNORE_ROUTES_WITH_LINKDOWN)) < 0)

		goto nla_put_failure;



out:
@@ -2205,20 +2206,19 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, 
{

	struct net *net = sock_net(in_skb->sk);

	struct nlattr *tb[NETCONFA_MAX + 1];

	const struct ipv4_devconf *devconf;

	struct in_device *in_dev = NULL;

	struct net_device *dev = NULL;

	struct sk_buff *skb;

	struct ipv4_devconf *devconf;

	struct in_device *in_dev;

	struct net_device *dev;

	int ifindex;

	int err;



	err = inet_netconf_valid_get_req(in_skb, nlh, tb, extack);

	if (err)

		goto errout;

		return err;



	err = -EINVAL;

	if (!tb[NETCONFA_IFINDEX])

		goto errout;

		return -EINVAL;



	ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);

	switch (ifindex) {
@@ -2229,10 +2229,10 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, 
		devconf = net->ipv4.devconf_dflt;

		break;

	default:

		dev = __dev_get_by_index(net, ifindex);

		if (!dev)

			goto errout;

		in_dev = __in_dev_get_rtnl(dev);

		err = -ENODEV;

		dev = dev_get_by_index(net, ifindex);

		if (dev)

			in_dev = in_dev_get(dev);

		if (!in_dev)

			goto errout;

		devconf = &in_dev->cnf;
@@ -2256,6 +2256,9 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, 
	}

	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);

errout:

	if (in_dev)

		in_dev_put(in_dev);

	dev_put(dev);

	return err;

}
@@ -2264,11 +2267,13 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, 
{

	const struct nlmsghdr *nlh = cb->nlh;

	struct net *net = sock_net(skb->sk);

	int h, s_h;

	int idx, s_idx;

	struct {

		unsigned long ifindex;

		unsigned int all_default;

	} *ctx = (void *)cb->ctx;

	const struct in_device *in_dev;

	struct net_device *dev;

	struct in_device *in_dev;

	struct hlist_head *head;

	int err = 0;



	if (cb->strict_check) {

		struct netlink_ext_ack *extack = cb->extack;
@@ -2285,64 +2290,47 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, 
		}

	}



	s_h = cb->args[0];

	s_idx = idx = cb->args[1];



	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {

		idx = 0;

		head = &net->dev_index_head[h];

	rcu_read_lock();

		cb->seq = inet_base_seq(net);

		hlist_for_each_entry_rcu(dev, head, index_hlist) {

			if (idx < s_idx)

				goto cont;

	for_each_netdev_dump(net, dev, ctx->ifindex) {

		in_dev = __in_dev_get_rcu(dev);

		if (!in_dev)

				goto cont;



			if (inet_netconf_fill_devconf(skb, dev->ifindex,

			continue;

		err = inet_netconf_fill_devconf(skb, dev->ifindex,

						&in_dev->cnf,

						NETLINK_CB(cb->skb).portid,

						nlh->nlmsg_seq,

						      RTM_NEWNETCONF,

						      NLM_F_MULTI,

						      NETCONFA_ALL) < 0) {

				rcu_read_unlock();

						RTM_NEWNETCONF, NLM_F_MULTI,

						NETCONFA_ALL);

		if (err < 0)

			goto done;

	}

			nl_dump_check_consistent(cb, nlmsg_hdr(skb));

cont:

			idx++;

		}

		rcu_read_unlock();

	}

	if (h == NETDEV_HASHENTRIES) {

		if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,

	if (ctx->all_default == 0) {

		err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,

						net->ipv4.devconf_all,

						NETLINK_CB(cb->skb).portid,

						nlh->nlmsg_seq,

						RTM_NEWNETCONF, NLM_F_MULTI,

					      NETCONFA_ALL) < 0)

						NETCONFA_ALL);

		if (err < 0)

			goto done;

		else

			h++;

		ctx->all_default++;

	}

	if (h == NETDEV_HASHENTRIES + 1) {

		if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,

	if (ctx->all_default == 1) {

		err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,

						net->ipv4.devconf_dflt,

						NETLINK_CB(cb->skb).portid,

						nlh->nlmsg_seq,

						RTM_NEWNETCONF, NLM_F_MULTI,

					      NETCONFA_ALL) < 0)

						NETCONFA_ALL);

		if (err < 0)

			goto done;

		else

			h++;

		ctx->all_default++;

	}

done:

	cb->args[0] = h;

	cb->args[1] = idx;



	return skb->len;

	if (err < 0 && likely(skb->len))

		err = skb->len;

	rcu_read_unlock();

	return err;

}



#ifdef CONFIG_SYSCTL
@@ -2825,5 +2813,6 @@ void __init devinet_init(void) 
	rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, 0);

	rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0);

	rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,

		      inet_netconf_dump_devconf, 0);

		      inet_netconf_dump_devconf,

		      RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED);

}

net/ipv4/igmp.c

+2 −2
Original line number Diff line number Diff line
@@ -120,12 +120,12 @@ 
 */



#define IGMP_V1_SEEN(in_dev) \

	(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \

	(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \

	 IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1 || \

	 ((in_dev)->mr_v1_seen && \

	  time_before(jiffies, (in_dev)->mr_v1_seen)))

#define IGMP_V2_SEEN(in_dev) \

	(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \

	(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \

	 IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2 || \

	 ((in_dev)->mr_v2_seen && \

	  time_before(jiffies, (in_dev)->mr_v2_seen)))

net/ipv4/proc.c

+1 −1
Original line number Diff line number Diff line
@@ -395,7 +395,7 @@ static int snmp_seq_show_ipstats(struct seq_file *seq, void *v) 
		seq_printf(seq, " %s", snmp4_ipstats_list[i].name);



	seq_printf(seq, "\nIp: %d %d",

		   IPV4_DEVCONF_ALL(net, FORWARDING) ? 1 : 2,

		   IPV4_DEVCONF_ALL_RO(net, FORWARDING) ? 1 : 2,

		   READ_ONCE(net->ipv4.sysctl_ip_default_ttl));



	BUILD_BUG_ON(offsetof(struct ipstats_mib, mibs) != 0);

net/ipv4/route.c

+2 −2
Original line number Diff line number Diff line
@@ -2313,7 +2313,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
		if (IN_DEV_BFORWARD(in_dev))

			goto make_route;

		/* not do cache if bc_forwarding is enabled */

		if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))

		if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))

			do_cache = false;

		goto brd_input;

	}
@@ -2993,7 +2993,7 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 
#ifdef CONFIG_IP_MROUTE

			if (ipv4_is_multicast(dst) &&

			    !ipv4_is_local_multicast(dst) &&

			    IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {

			    IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {

				int err = ipmr_get_route(net, skb,

							 fl4->saddr, fl4->daddr,

							 r, portid);