tcp: add some mibs to track collapsing

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index 7a6e6bba4a71..aee3f1e1d1ce 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -216,6 +216,9 @@ enum
         LINUX_MIB_TCPSPURIOUSRTOS,              /* TCPSpuriousRTOs */
         LINUX_MIB_TCPMD5NOTFOUND,               /* TCPMD5NotFound */
         LINUX_MIB_TCPMD5UNEXPECTED,             /* TCPMD5Unexpected */
+        LINUX_MIB_SACKSHIFTED,
+        LINUX_MIB_SACKMERGED,
+        LINUX_MIB_SACKSHIFTFALLBACK,
         __LINUX_MIB_MAX
 };
 
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index a631a1f110ca..731789bb499f 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -234,6 +234,9 @@ static const struct snmp_mib snmp4_net_list[] = {
         SNMP_MIB_ITEM("TCPSpuriousRTOs", LINUX_MIB_TCPSPURIOUSRTOS),
         SNMP_MIB_ITEM("TCPMD5NotFound", LINUX_MIB_TCPMD5NOTFOUND),
         SNMP_MIB_ITEM("TCPMD5Unexpected", LINUX_MIB_TCPMD5UNEXPECTED),
+        SNMP_MIB_ITEM("TCPSackShifted", LINUX_MIB_SACKSHIFTED),
+        SNMP_MIB_ITEM("TCPSackMerged", LINUX_MIB_SACKMERGED),
+        SNMP_MIB_ITEM("TCPSackShiftFallback", LINUX_MIB_SACKSHIFTFALLBACK),
         SNMP_MIB_SENTINEL
 };
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e6291dde3348..9f8a80ba17bd 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1415,6 +1415,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
 
         if (skb->len > 0) {
                 BUG_ON(!tcp_skb_pcount(skb));
+                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKSHIFTED);
                 return 0;
         }
 
@@ -1436,6 +1437,8 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
         tcp_unlink_write_queue(skb, sk);
         sk_wmem_free_skb(sk, skb);
 
+        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKMERGED);
+
         return 1;
 }
 
@@ -1594,6 +1597,7 @@ noop:
         return skb;
 
 fallback:
+        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKSHIFTFALLBACK);
         return NULL;
 }