[TCP]: Missing SNMP stats.

include/net/tcp.h

@@ -31,6 +31,7 @@
 #include <linux/percpu.h>
 #include <net/checksum.h>
 #include <net/sock.h>
+#include <net/snmp.h>
 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
 #include <linux/ipv6.h>
 #endif
@@ -639,6 +640,8 @@ DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
 #define TCP_INC_STATS_BH(field)		SNMP_INC_STATS_BH(tcp_statistics, field)
 #define TCP_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(tcp_statistics, field)
 #define TCP_DEC_STATS(field)		SNMP_DEC_STATS(tcp_statistics, field)
+#define TCP_ADD_STATS_BH(field, val)	SNMP_ADD_STATS_BH(tcp_statistics, field, val)
+#define TCP_ADD_STATS_USER(field, val)	SNMP_ADD_STATS_USER(tcp_statistics, field, val)
 
 extern __inline__ void		tcp_put_port(struct sock *sk);
 extern void			tcp_inherit_port(struct sock *sk, struct sock *child);
@@ -1398,6 +1401,9 @@ static __inline__ void tcp_set_state(struct sock *sk, int state)
 		break;
 
 	case TCP_CLOSE:
+		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
+			TCP_INC_STATS(TcpEstabResets);
+
 		sk->prot->unhash(sk);
 		if (sk->prev && !(sk->userlocks&SOCK_BINDPORT_LOCK))
 			tcp_put_port(sk);
@@ -1878,4 +1884,13 @@ static inline int tcp_use_frto(const struct sock *sk)
 		       tp->snd_una + tp->snd_wnd));
 }
 
+static inline void tcp_mib_init(void)
+{
+	/* See RFC 2012 */
+	TCP_ADD_STATS_USER(TcpRtoAlgorithm, 1);
+	TCP_ADD_STATS_USER(TcpRtoMin, TCP_RTO_MIN*1000/HZ);
+	TCP_ADD_STATS_USER(TcpRtoMax, TCP_RTO_MAX*1000/HZ);
+	TCP_ADD_STATS_USER(TcpMaxConn, -1);
+}
+
 #endif	/* _TCP_H */

net/ipv4/af_inet.c

@@ -1108,6 +1108,8 @@ static int __init init_ipv4_mibs(void)
 		}
 	}
 
+	(void) tcp_mib_init();
+
 	return 0;
 }
 

net/ipv4/proc.c

@@ -143,9 +143,15 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 			"InSegs OutSegs RetransSegs InErrs OutRsts\nTcp:");
 
 	for (i = 0;
-	     i < offsetof(struct tcp_mib, __pad) / sizeof(unsigned long); i++)
+	     i < offsetof(struct tcp_mib, __pad) / sizeof(unsigned long); i++) {
+		if (i == (offsetof(struct tcp_mib, TcpMaxConn) / sizeof(unsigned long)))
+			/* MaxConn field is negative, RFC 2012 */
+			seq_printf(seq, " %ld", 
+				   fold_field((void **) tcp_statistics, i));
+		else
 			seq_printf(seq, " %lu", 
 				   fold_field((void **) tcp_statistics, i));
+	}
 
 	seq_printf(seq, "\nUdp: InDatagrams NoPorts InErrors OutDatagrams\n"
 			"Udp:");