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Commit 698e2a8d authored by Marco Angaroni's avatar Marco Angaroni Committed by Simon Horman
Browse files

ipvs: make drop_entry protection effective for SIP-pe 



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: default avatarMarco Angaroni <marcoangaroni@gmail.com>
Acked-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent cb39ad8b

net/netfilter/ipvs/ip_vs_conn.c

+19 −3
Original line number Diff line number Diff line
@@ -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;

			}

net/netfilter/ipvs/ip_vs_core.c

+7 −1
Original line number Diff line number Diff line
@@ -612,6 +612,9 @@ 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 */



		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;