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ipvs: make drop_entry protection effective for SIP-pe

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DoS protection policy that deletes connections to avoid out of memory is
currently not effective for SIP-pe plus OPS-mode for two reasons:
  1) connection templates (holding SIP call-id) are always skipped in
     ip_vs_random_dropentry()
  2) in_pkts counter (used by drop_entry algorithm) is not incremented
     for connection templates

This patch addresses such problems with the following changes:
  a) connection templates associated (via their dest) to virtual-services
     configured in OPS mode are included in ip_vs_random_dropentry()
     monitoring. This applies to SIP-pe over UDP (which requires OPS mode),
     but is more general principle: when OPS is controlled by templates
     memory can be used only by templates themselves, since OPS conns are
     deleted after packet is forwarded.
  b) OPS connections, if controlled by a template, cause increment of
     in_pkts counter of their template. This is already happening but only
     in case director is in master-slave mode (see ip_vs_sync_conn()).

Signed-off-by: Marco Angaroni <marcoangaroni@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
This commit is contained in:
Marco Angaroni 2016-04-26 21:20:22 +02:00 committed by Simon Horman
parent cb39ad8b8e
commit 698e2a8dca
2 changed files with 26 additions and 4 deletions
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22
net/netfilter/ipvs/ip_vs_conn.c
View file

@ -1261,6 +1261,16 @@ static inline int todrop_entry(struct ip_vs_conn *cp)
return 1;
}
static inline bool ip_vs_conn_ops_mode(struct ip_vs_conn *cp)
{
struct ip_vs_service *svc;
if (!cp->dest)
return false;
svc = rcu_dereference(cp->dest->svc);
return svc && (svc->flags & IP_VS_SVC_F_ONEPACKET);
}
/* Called from keventd and must protect itself from softirqs */
void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
{
@ -1275,11 +1285,16 @@ void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
unsigned int hash = prandom_u32() & ip_vs_conn_tab_mask;
hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
if (cp->flags & IP_VS_CONN_F_TEMPLATE)
/* connection template */
continue;
if (cp->ipvs != ipvs)
continue;
if (cp->flags & IP_VS_CONN_F_TEMPLATE) {
if (atomic_read(&cp->n_control) ||
!ip_vs_conn_ops_mode(cp))
continue;
else
/* connection template of OPS */
goto try_drop;
}
if (cp->protocol == IPPROTO_TCP) {
switch(cp->state) {
case IP_VS_TCP_S_SYN_RECV:
@ -1307,6 +1322,7 @@ void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
continue;
}
} else {
try_drop:
if (!todrop_entry(cp))
continue;
}

8
net/netfilter/ipvs/ip_vs_core.c
View file

@ -612,7 +612,10 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
ret = cp->packet_xmit(skb, cp, pd->pp, iph);
/* do not touch skb anymore */
atomic_inc(&cp->in_pkts);
if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) && cp->control)
atomic_inc(&cp->control->in_pkts);
else
atomic_inc(&cp->in_pkts);
ip_vs_conn_put(cp);
return ret;
}
@ -1991,6 +1994,9 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int
if (ipvs->sync_state & IP_VS_STATE_MASTER)
ip_vs_sync_conn(ipvs, cp, pkts);
else if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) && cp->control)
/* increment is done inside ip_vs_sync_conn too */
atomic_inc(&cp->control->in_pkts);
ip_vs_conn_put(cp);
return ret;