Commit 16748707 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

inet: use xa_array iterator to implement inet_netconf_dump_devconf() 



1) inet_netconf_dump_devconf() can run under RCU protection
   instead of RTNL.

2) properly return 0 at the end of a dump, avoiding an
   an extra recvmsg() system call.

3) Do not use inet_base_seq() anymore, for_each_netdev_dump()
   has nice properties. Restarting a GETDEVCONF dump if a device has
   been added/removed or if net->ipv4.dev_addr_genid has changed is moot.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240227092411.2315725-4-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent bbcf9105

net/ipv4/devinet.c

+43 −58
Original line number Diff line number Diff line
@@ -2267,11 +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;
@@ -2288,64 +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
@@ -2829,5 +2814,5 @@ void __init devinet_init(void) 
	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,

		      RTNL_FLAG_DOIT_UNLOCKED);

		      RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED);

}