From: Sven Wegener <sven.wegener@xxxxxxxxxxx>
A backlog connection is a connection that is on its way from inactive to
active. Speaking in TCP language, a connection from which we've seen the
initial SYN packet, but the three-way handshake hasn't finished yet.
These connections are expected to move to active soon. When a
destination is overloaded or isn't able to successfully establish
connections for various reasons, this count increases quickly and is an
indication for a problem.
Signed-off-by: Sven Wegener <sven.wegener@xxxxxxxxxxx>
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
Hi Sven,
here is an updated though as yet untested version of your patch from Julian
to take into account recent changes. In particualr, the ip_vs_sync.c
portion is no longer needed as only the flags in the first 16 bits are
synced now. It applies against Patrick McHardy's nf-next-2.6 tree.
You mentioned in your original post that you would work on an ipvsadm
patch for this feature. Have you had time to do so?
Also, are you in a position to test this? If not I can do so.
Hi Mohan,
do you have any thoughts on an appropriate to add this feature to SCTP?
diff -urp net-next-2.6-e548833-nfct/linux/include/linux/ip_vs.h linux/include/linux/ip_vs.h
--- net-next-2.6-e548833-nfct/linux/include/linux/ip_vs.h 2010-09-15 11:28:02.000000000 +0300
+++ linux/include/linux/ip_vs.h 2010-09-26 15:21:53.507865229 +0300
@@ -91,6 +91,7 @@
/* Flags that are not sent to backup server start from bit 16 */
#define IP_VS_CONN_F_NFCT (1 << 16) /* use netfilter conntrack */
+#define IP_VS_CONN_F_BACKLOG (1 << 17) /* backlog connection */
/* Connection flags from destination that can be changed by user space */
#define IP_VS_CONN_F_DEST_MASK (IP_VS_CONN_F_FWD_MASK | \
@@ -360,6 +361,7 @@ enum {
IPVS_DEST_ATTR_PERSIST_CONNS, /* persistent connections */
IPVS_DEST_ATTR_STATS, /* nested attribute for dest stats */
+ IPVS_DEST_ATTR_BACKLOG_CONNS, /* backlog connections */
__IPVS_DEST_ATTR_MAX,
};
diff -urp net-next-2.6-e548833-nfct/linux/include/net/ip_vs.h linux/include/net/ip_vs.h
--- net-next-2.6-e548833-nfct/linux/include/net/ip_vs.h 2010-09-16 08:53:04.000000000 +0300
+++ linux/include/net/ip_vs.h 2010-09-26 15:31:27.369865994 +0300
@@ -501,6 +501,7 @@ struct ip_vs_dest {
/* connection counters and thresholds */
atomic_t activeconns; /* active connections */
atomic_t inactconns; /* inactive connections */
+ atomic_t backlogconns; /* backlog connections */
atomic_t persistconns; /* persistent connections */
__u32 u_threshold; /* upper threshold */
__u32 l_threshold; /* lower threshold */
diff -urp net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_conn.c linux/net/netfilter/ipvs/ip_vs_conn.c
--- net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_conn.c 2010-09-15 11:14:13.000000000 +0300
+++ linux/net/netfilter/ipvs/ip_vs_conn.c 2010-09-26 15:24:48.292865793 +0300
@@ -611,6 +611,8 @@ static inline void ip_vs_unbind_dest(str
} else {
atomic_dec(&dest->activeconns);
}
+ if (cp->flags & IP_VS_CONN_F_BACKLOG)
+ atomic_dec(&dest->backlogconns);
} else {
/* It is a persistent connection/template, so decrease
the peristent connection counter */
diff -urp net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_ctl.c linux/net/netfilter/ipvs/ip_vs_ctl.c
--- net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_ctl.c 2010-09-16 08:56:34.000000000 +0300
+++ linux/net/netfilter/ipvs/ip_vs_ctl.c 2010-09-26 15:26:45.407867200 +0300
@@ -2593,6 +2593,7 @@ static const struct nla_policy ip_vs_des
[IPVS_DEST_ATTR_INACT_CONNS] = { .type = NLA_U32 },
[IPVS_DEST_ATTR_PERSIST_CONNS] = { .type = NLA_U32 },
[IPVS_DEST_ATTR_STATS] = { .type = NLA_NESTED },
+ [IPVS_DEST_ATTR_BACKLOG_CONNS] = { .type = NLA_U32 },
};
static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
@@ -2840,6 +2841,8 @@ static int ip_vs_genl_fill_dest(struct s
atomic_read(&dest->activeconns));
NLA_PUT_U32(skb, IPVS_DEST_ATTR_INACT_CONNS,
atomic_read(&dest->inactconns));
+ NLA_PUT_U32(skb, IPVS_DEST_ATTR_BACKLOG_CONNS,
+ atomic_read(&dest->backlogconns));
NLA_PUT_U32(skb, IPVS_DEST_ATTR_PERSIST_CONNS,
atomic_read(&dest->persistconns));
diff -urp net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_proto_tcp.c linux/net/netfilter/ipvs/ip_vs_proto_tcp.c
--- net-next-2.6-e548833-nfct/linux/net/netfilter/ipvs/ip_vs_proto_tcp.c 2010-09-10 08:27:33.000000000 +0300
+++ linux/net/netfilter/ipvs/ip_vs_proto_tcp.c 2010-09-26 15:29:18.425865407 +0300
@@ -510,6 +510,15 @@ set_tcp_state(struct ip_vs_protocol *pp,
atomic_dec(&dest->inactconns);
cp->flags &= ~IP_VS_CONN_F_INACTIVE;
}
+ if (new_state == IP_VS_TCP_S_SYN_RECV &&
+ !(cp->flags & IP_VS_CONN_F_BACKLOG)) {
+ atomic_inc(&dest->backlogconns);
+ cp->flags |= IP_VS_CONN_F_BACKLOG;
+ } else if (new_state == IP_VS_TCP_S_ESTABLISHED &&
+ cp->flags & IP_VS_CONN_F_BACKLOG) {
+ atomic_dec(&dest->backlogconns);
+ cp->flags &= ~IP_VS_CONN_F_BACKLOG;
+ }
}
}
--
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