[PATCH] ipvs: Fix reuse connection if real server is dead

[Simon Horman <horms@xxxxxxxxxxxx>]

From: Grzegorz Lyczba <grzegorz.lyczba@xxxxxxxxx>

Expire cached connection for new TCP/SCTP connection if real server is down

Signed-off-by: Grzegorz Lyczba <grzegorz.lyczba@xxxxxxxxx>
Acked-by: Hans Schillstrom <hans@xxxxxxxxxxxxxxx>
Acked-by: Julian Anastasov <ja@xxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
 net/netfilter/ipvs/ip_vs_core.c |   35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 085b588..05565d2 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -1001,6 +1001,32 @@ static inline int is_tcp_reset(const struct sk_buff 
*skb, int nh_len)
        return th->rst;
 }
 
+static inline bool is_new_conn(const struct sk_buff *skb,
+                              struct ip_vs_iphdr *iph)
+{
+       switch (iph->protocol) {
+       case IPPROTO_TCP: {
+               struct tcphdr _tcph, *th;
+
+               th = skb_header_pointer(skb, iph->len, sizeof(_tcph), &_tcph);
+               if (th == NULL)
+                       return false;
+               return th->syn;
+       }
+       case IPPROTO_SCTP: {
+               sctp_chunkhdr_t *sch, schunk;
+
+               sch = skb_header_pointer(skb, iph->len + sizeof(sctp_sctphdr_t),
+                                        sizeof(schunk), &schunk);
+               if (sch == NULL)
+                       return false;
+               return sch->type == SCTP_CID_INIT;
+       }
+       default:
+               return false;
+       }
+}
+
 /* Handle response packets: rewrite addresses and send away...
  */
 static unsigned int
@@ -1612,6 +1638,15 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int 
af)
         * Check if the packet belongs to an existing connection entry
         */
        cp = pp->conn_in_get(af, skb, &iph, 0);
+
+       if (unlikely(sysctl_expire_nodest_conn(ipvs)) && cp && cp->dest &&
+           unlikely(!atomic_read(&cp->dest->weight)) && !iph.fragoffs &&
+           is_new_conn(skb, &iph)) {
+               ip_vs_conn_expire_now(cp);
+               __ip_vs_conn_put(cp);
+               cp = NULL;
+       }
+
        if (unlikely(!cp) && !iph.fragoffs) {
                /* No (second) fragments need to enter here, as nf_defrag_ipv6
                 * replayed fragment zero will already have created the cp
-- 
1.7.10.4

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