bin/41979: netstat -s reports tcp6 stats when INET6 is not configured

[fair%netbsd.org@localhost]

>Number:         41979
>Category:       bin
>Synopsis:       netstat -s reports tcp6 stats when INET6 is not configured
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Sep 03 07:25:00 +0000 2009
>Originator:     Erik E. Fair
>Release:        NetBSD 5.0_STABLE
>Organization:
        The NetBSD Project
>Environment:
        
        
System: NetBSD digital.clock.org 5.0_STABLE (FLAPJACK2) #1: Wed Aug  5 16:42:56 
PDT 2009 
root%fast.clock.org@localhost:/var/obj/sys/arch/sparc64/compile/FLAPJACK2 
sparc64
Architecture: sparc64
Machine: sparc64
>Description:
        On a Sun Netra T1 model 200 (500 MHz UltraSPARC II), run
        a custom kernel that has NO IP version 6 support at all,
        and observe that netstat -s still reports statistics for
        tcp6, which oddly appear identical to "tcp" (IP version 4):

ip:
        15776958 total packets received
        0 bad header checksums
        0 with size smaller than minimum
        0 with data size < data length
        0 with length > max ip packet size
        0 with header length < data size
        0 with data length < header length
        0 with bad options
        0 with incorrect version number
        1031346 fragments received
        0 fragments dropped (dup or out of space)
        0 fragments dropped (out of ipqent)
        0 malformed fragments dropped
        39 fragments dropped after timeout
        145505 packets reassembled ok
        14883535 packets for this host
        2 packets for unknown/unsupported protocol
        0 packets forwarded (0 packets fast forwarded)
        7580 packets not forwardable
        0 redirects sent
        0 packets no matching gif found
        13706415 packets sent from this host
        22908 packets sent with fabricated ip header
        0 output packets dropped due to no bufs, etc.
        0 output packets discarded due to no route
        307148 output datagrams fragmented
        1908163 fragments created
        0 datagrams that can't be fragmented
        0 datagrams with bad address in header
icmp:
        50537 calls to icmp_error
        0 errors not generated because old message was icmp
        Output histogram:
                echo reply: 95699
                destination unreachable: 48296
        51 messages with bad code fields
        0 messages < minimum length
        0 bad checksums
        0 messages with bad length
        Input histogram:
                echo reply: 24068
                destination unreachable: 5901
                source quench: 4149
                routing redirect: 4
                echo: 95699
                time exceeded: 138
        95699 message responses generated
        0 path MTU changes
igmp:
        23238 messages received
        0 messages received with too few bytes
        0 messages received with bad checksum
        23238 membership queries received
        0 membership queries received with invalid field(s)
        0 membership reports received
        0 membership reports received with invalid field(s)
        0 membership reports received for groups to which we belong
        0 membership reports sent
tcp:
        3273666 packets sent
                962381 data packets (361140721 bytes)
                24503 data packets (1468966 bytes) retransmitted
                1513514 ack-only packets (2313750 delayed)
                0 URG only packets
                0 window probe packets
                732954 window update packets
                40314 control packets
                0 send attempts resulted in self-quench
        4950882 packets received
                893401 acks (for 358471790 bytes)
                0 duplicate acks
                0 acks for unsent data
                3421460 packets (3361680517 bytes) received in-sequence
                29491 completely duplicate packets (3509318 bytes)
                1 old duplicate packet
                491 packets with some dup. data (316810 bytes duped)
                36962 out-of-order packets (36422686 bytes)
                0 packets (0 bytes) of data after window
                0 window probes
                3641 window update packets
                18668 packets received after close
                10 discarded for bad checksums
                0 discarded for bad header offset fields
                0 discarded because packet too short
        441 connection requests
        37939 connection accepts
        38360 connections established (including accepts)
        50889 connections closed (including 2852 drops)
        19 embryonic connections dropped
        0 delayed frees of tcpcb
        883282 segments updated rtt (of 807252 attempts)
        25192 retransmit timeouts
                1947 connections dropped by rexmit timeout
        0 persist timeouts (resulting in 0 dropped connections)
        198 keepalive timeouts
                184 keepalive probes sent
                14 connections dropped by keepalive
        3579 correct ACK header predictions
        2857150 correct data packet header predictions
        1002935 PCB hash misses
        903707 dropped due to no socket
        2 connections drained due to memory shortage
        1981 PMTUD blackholes detected
        18770 bad connection attempts
        38262 SYN cache entries added
                0 hash collisions
                37939 completed
                0 aborted (no space to build PCB)
                122 timed out
                0 dropped due to overflow
                0 dropped due to bucket overflow
                201 dropped due to RST
                0 dropped due to ICMP unreachable
                0 delayed free of SYN cache entries
        1694 SYN,ACKs retransmitted
        371 duplicate SYNs received for entries already in the cache
        0 SYNs dropped (no route or no space)
        0 packets with bad signature
        0 packets with good signature
        0 sucessful ECN handshakes
        0 packets with ECN CE bit
        0 packets ECN ECT(0) bit
udp:
        9779456 datagrams received
        0 with incomplete header
        0 with bad data length field
        1 with bad checksum
        50535 dropped due to no socket
        291934 broadcast/multicast datagrams dropped due to no socket
        102 dropped due to full socket buffers
        9436884 delivered
        9225947 PCB hash misses
        9326971 datagrams output
ipsec:
        0 inbound packets processed successfully
        0 inbound packets violated process security policy
        0 inbound packets with no SA available
        0 invalid inbound packets
        0 inbound packets failed due to insufficient memory
        0 inbound packets failed getting SPI
        0 inbound packets failed on AH replay check
        0 inbound packets failed on ESP replay check
        0 inbound packets considered authentic
        0 inbound packets failed on authentication
        0 outbound packets processed successfully
        0 outbound packets violated process security policy
        0 outbound packets with no SA available
        0 invalid outbound packets
        0 outbound packets failed due to insufficient memory
        0 outbound packets with no route
        23345887 SPD cache lookups
        19053695 SPD cache misses
tcp6:
        3273666 packets sent
                962381 data packets (361140721 bytes)
                24503 data packets (1468966 bytes) retransmitted
                1513514 ack-only packets (2313750 delayed)
                0 URG only packets
                0 window probe packets
                732954 window update packets
                40314 control packets
                0 send attempts resulted in self-quench
        4950882 packets received
                893401 acks (for 358471790 bytes)
                0 duplicate acks
                0 acks for unsent data
                3421460 packets (3361680517 bytes) received in-sequence
                29491 completely duplicate packets (3509318 bytes)
                1 old duplicate packet
                491 packets with some dup. data (316810 bytes duped)
                36962 out-of-order packets (36422686 bytes)
                0 packets (0 bytes) of data after window
                0 window probes
                3641 window update packets
                18668 packets received after close
                10 discarded for bad checksums
                0 discarded for bad header offset fields
                0 discarded because packet too short
        441 connection requests
        37939 connection accepts
        38360 connections established (including accepts)
        50889 connections closed (including 2852 drops)
        19 embryonic connections dropped
        0 delayed frees of tcpcb
        883282 segments updated rtt (of 807252 attempts)
        25192 retransmit timeouts
                1947 connections dropped by rexmit timeout
        0 persist timeouts (resulting in 0 dropped connections)
        198 keepalive timeouts
                184 keepalive probes sent
                14 connections dropped by keepalive
        3579 correct ACK header predictions
        2857150 correct data packet header predictions
        1002935 PCB hash misses
        903707 dropped due to no socket
        2 connections drained due to memory shortage
        1981 PMTUD blackholes detected
        18770 bad connection attempts
        38262 SYN cache entries added
                0 hash collisions
                37939 completed
                0 aborted (no space to build PCB)
                122 timed out
                0 dropped due to overflow
                0 dropped due to bucket overflow
                201 dropped due to RST
                0 dropped due to ICMP unreachable
                0 delayed free of SYN cache entries
        1694 SYN,ACKs retransmitted
        371 duplicate SYNs received for entries already in the cache
        0 SYNs dropped (no route or no space)
        0 packets with bad signature
        0 packets with good signature
        0 sucessful ECN handshakes
        0 packets with ECN CE bit
        0 packets ECN ECT(0) bit
ipsec6:
        0 inbound packets processed successfully
        0 inbound packets violated process security policy
        0 inbound packets with no SA available
        0 invalid inbound packets
        0 inbound packets failed due to insufficient memory
        0 inbound packets failed getting SPI
        0 inbound packets failed on AH replay check
        0 inbound packets failed on ESP replay check
        0 inbound packets considered authentic
        0 inbound packets failed on authentication
        0 outbound packets processed successfully
        0 outbound packets violated process security policy
        0 outbound packets with no SA available
        0 invalid outbound packets
        0 outbound packets failed due to insufficient memory
        0 outbound packets with no route
        23345887 SPD cache lookups
        19053695 SPD cache misses
arp:
        18938 packets sent
                2563 reply packets
                16375 request packets
        1747882 packets received
                11863 reply packets
                1735772 valid request packets
                1736043 broadcast/multicast packets
                0 packets with unknown protocol type
                0 packets with bad (short) length
                0 packets with null target IP address
                247 packets with null source IP address
                0 could not be mapped to an interface
                0 packets sourced from a local hardware address
                0 packets with a broadcast source hardware address
                0 duplicates for a local IP address
                0 attempts to overwrite a static entry
                0 packets received on wrong interface
                0 entrys overwritten
                0 changes in hardware address length
        7826 packets deferred pending ARP resolution
                2513 sent
                4841 dropped
        0 failures to allocate llinfo
pfkey:
        0 requests sent from userland
        0 bytes sent from userland
        0 messages with invalid length field
        0 messages with invalid version field
        0 messages with invalid message type field
        0 messages too short
        0 messages with memory allocation failure
        0 messages with duplicate extension
        0 messages with invalid extension type
        0 messages with invalid sa type
        0 messages with invalid address extension
        0 requests sent to userland
        0 bytes sent to userland
        0 messages toward single socket
        0 messages toward all sockets
        0 messages toward registered sockets
        0 messages with memory allocation failure
ddp:
        0 packets with short headers 
        0 packets with long headers 
        0 packets with no checksum 
        0 packets too short 
        0 packets with bad checksum 
        0 packets with not enough data 
        0 packets forwarded 
        0 packets encapsulated 
        0 packets rcvd for unreachable dest 
        0 packets dropped due to no socket space 
TP not configured

>How-To-Repeat:
        1. configure & compile a kernel with INET6 explicitly disabled
        2. run "netstat -s" and observe statistics reported for tcp6 which 
should not be,
                and note that they appear identical to "tcp" (IP version 4).
        3. become rather vexed that netstat is picking up the wrong stats
>Fix:
        

>Unformatted: