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: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240227092411.2315725-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-02-27 09:24:11 +00:00 committed by Jakub Kicinski
parent bbcf91053b
commit 167487070d
1 changed files with 43 additions and 58 deletions

View File

@ -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;
in_dev = __in_dev_get_rcu(dev);
if (!in_dev)
goto cont;
if (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();
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,
net->ipv4.devconf_all,
NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq,
RTM_NEWNETCONF, NLM_F_MULTI,
NETCONFA_ALL) < 0)
rcu_read_lock();
for_each_netdev_dump(net, dev, ctx->ifindex) {
in_dev = __in_dev_get_rcu(dev);
if (!in_dev)
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);
if (err < 0)
goto done;
else
h++;
}
if (h == NETDEV_HASHENTRIES + 1) {
if (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)
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);
if (err < 0)
goto done;
else
h++;
ctx->all_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);
if (err < 0)
goto done;
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);
}