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netfilter: conntrack: avoid reload of ct->status

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Compiler can't merge the two test_bit() calls, so load ct->status
once and use non-atomic accesses.

This is fine because IPS_EXPECTED or NAT_CLASH are either set at ct
creation time or not at all, but compiler can't know that.

Signed-off-by: Florian Westphal <fw@strlen.de>
This commit is contained in:
Florian Westphal 2023-01-02 12:46:12 +01:00
parent 50bfbb8957
commit 4883ec512c
2 changed files with 11 additions and 8 deletions
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9
net/netfilter/nf_conntrack_core.c
View file

@ -1854,14 +1854,15 @@ resolve_normal_ct(struct nf_conn *tmpl,
if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
ctinfo = IP_CT_ESTABLISHED_REPLY; ctinfo = IP_CT_ESTABLISHED_REPLY;
} else { } else {
unsigned long status = READ_ONCE(ct->status);
/* Once we've had two way comms, always ESTABLISHED. */ /* Once we've had two way comms, always ESTABLISHED. */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { if (likely(status & IPS_SEEN_REPLY))
ctinfo = IP_CT_ESTABLISHED; ctinfo = IP_CT_ESTABLISHED;
} else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { else if (status & IPS_EXPECTED)
ctinfo = IP_CT_RELATED; ctinfo = IP_CT_RELATED;
} else { else
ctinfo = IP_CT_NEW; ctinfo = IP_CT_NEW;
}
} }
nf_ct_set(skb, ct, ctinfo); nf_ct_set(skb, ct, ctinfo);
return 0; return 0;

10
net/netfilter/nf_conntrack_proto_udp.c
View file

@ -88,6 +88,7 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
const struct nf_hook_state *state) const struct nf_hook_state *state)
{ {
unsigned int *timeouts; unsigned int *timeouts;
unsigned long status;
if (udp_error(skb, dataoff, state)) if (udp_error(skb, dataoff, state))
return -NF_ACCEPT; return -NF_ACCEPT;
@ -96,26 +97,27 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
if (!timeouts) if (!timeouts)
timeouts = udp_get_timeouts(nf_ct_net(ct)); timeouts = udp_get_timeouts(nf_ct_net(ct));
if (!nf_ct_is_confirmed(ct)) status = READ_ONCE(ct->status);
if ((status & IPS_CONFIRMED) == 0)
ct->proto.udp.stream_ts = 2 * HZ + jiffies; ct->proto.udp.stream_ts = 2 * HZ + jiffies;
/* If we've seen traffic both ways, this is some kind of UDP /* If we've seen traffic both ways, this is some kind of UDP
* stream. Set Assured. * stream. Set Assured.
*/ */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { if (status & IPS_SEEN_REPLY_BIT) {
unsigned long extra = timeouts[UDP_CT_UNREPLIED]; unsigned long extra = timeouts[UDP_CT_UNREPLIED];
bool stream = false; bool stream = false;
/* Still active after two seconds? Extend timeout. */ /* Still active after two seconds? Extend timeout. */
if (time_after(jiffies, ct->proto.udp.stream_ts)) { if (time_after(jiffies, ct->proto.udp.stream_ts)) {
extra = timeouts[UDP_CT_REPLIED]; extra = timeouts[UDP_CT_REPLIED];
stream = true; stream = (status & IPS_ASSURED) == 0;
} }
nf_ct_refresh_acct(ct, ctinfo, skb, extra); nf_ct_refresh_acct(ct, ctinfo, skb, extra);
/* never set ASSURED for IPS_NAT_CLASH, they time out soon */ /* never set ASSURED for IPS_NAT_CLASH, they time out soon */
if (unlikely((ct->status & IPS_NAT_CLASH))) if (unlikely((status & IPS_NAT_CLASH)))
return NF_ACCEPT; return NF_ACCEPT;
/* Also, more likely to be important, and not a probe */ /* Also, more likely to be important, and not a probe */