7. Network Commands¶

This command is used to display various types of network statistics. The information displayed can be specified using command line arguments in various combinations. The arguments are interpreted as follows:

-A

print All statistics

-i

print Inet Routes

-m

print MBUF Statistics

-f

print IF Statistics

-p

print IP Statistics

-c

print ICMP Statistics

-u

print UDP Statistics

-t

print TCP Statistics

The following is an example of using the netstats command to print the IP routing table:

[/] $ netstats -i
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
default         192.168.1.14       UGS         0        0      0 eth1
192.168.1.0     255.255.255.0      U           0        0      1 eth1
192.168.1.14    00:A0:C8:1C:EE:28  UHL         1        0   1219 eth1
192.168.1.51    00:1D:7E:0C:D0:7C  UHL         0      840   1202 eth1
192.168.1.151   00:1C:23:B2:0F:BB  UHL         1       23   1219 eth1

The following is an example of using the netstats command to print the MBUF statistics:

[/] $ netstats -m
************ MBUF STATISTICS ************
mbufs:2048       clusters: 128          free:  63
drops:   0          waits:   0        drains:   0
free:1967            data:79          header:2           socket:0
pcb:0              rtable:0           htable:0           atable:0
soname:0           soopts:0           ftable:0           rights:0
ifaddr:0          control:0          oobdata:0

The following is an example of using the netstats command to print the print the interface statistics:

[/] $ netstats -f
************ INTERFACE STATISTICS ************
***** eth1 *****
Ethernet Address: 00:04:9F:00:5B:21
Address:192.168.1.244   Broadcast Address:192.168.1.255   Net mask:255.255.255.0
Flags: Up Broadcast Running Active Multicast
Send queue limit:50          length:1           Dropped:0
Rx Interrupts:889            Not First:0        Not Last:0
Giant:0                      Non-octet:0
Bad CRC:0                    Overrun:0          Collision:0
Tx Interrupts:867            Deferred:0         Late Collision:0
Retransmit Limit:0           Underrun:0         Misaligned:0

The following is an example of using the netstats command to print the print IP statistics:

[/] $ netstats -p
************ IP Statistics ************
total packets received                    894
packets rcvd for unreachable dest          13
datagrams delivered to upper level        881
total ip packets generated here           871

The following is an example of using the netstats command to print the ICMP statistics:

[/] $ netstats -c
************ ICMP Statistics ************
Type 0 sent                 843
number of responses         843
Type 8 received             843

The following is an example of using the netstats command to print the UDP statistics:

[/] $ netstats -u
************ UDP Statistics ************

The following is an example of using the netstats command to print the TCP statistics:

[/] $ netstats -t
************ TCP Statistics ************
connections accepted                        1
connections established                     1
segs where we tried to get rtt              34
times we succeeded                          35
delayed acks sent                           2
total packets sent                          37
data packets sent                           35
data bytes sent                             2618
ack-only packets sent                       2
total packets received                      47
packets received in sequence                12
bytes received in sequence                  307
rcvd ack packets                            35
bytes acked by rcvd acks                    2590
times hdr predict ok for acks               27
times hdr predict ok for data pkts          10

This command is included in the default shell command set. When building a custom command set, define CONFIGURE_SHELL_COMMAND_NETSTATS to have this command included.

This command can be excluded from the shell command set by defining CONFIGURE_SHELL_NO_COMMAND_NETSTATS when all shell commands have been configured.

The netstats is implemented by a C language function which has the following prototype:

int rtems_shell_rtems_main_netstats(
    int    argc,
    char **argv
);

The configuration structure for the netstats has the following prototype:

extern rtems_shell_cmd_t rtems_shell_NETSTATS_Command;

The following is an example of how to use ifconfig:

************ INTERFACE STATISTICS ************
***** eth1 *****
Ethernet Address: 00:04:9F:00:5B:21
Address:192.168.1.244   Broadcast Address:192.168.1.255   Net mask:255.255.255.0
Flags: Up Broadcast Running Active Multicast
Send queue limit:50                length:1                Dropped:0
Rx Interrupts:5391              Not First:0               Not Last:0
Giant:0                         Non-octet:0
Bad CRC:0                         Overrun:0              Collision:0
Tx Interrupts:5256               Deferred:0         Late Collision:0
Retransmit Limit:0               Underrun:0             Misaligned:0

This command is included in the default shell command set. When building a custom command set, define CONFIGURE_SHELL_COMMAND_IFCONFIG to have this command included.

This command can be excluded from the shell command set by defining CONFIGURE_SHELL_NO_COMMAND_IFCONFIG when all shell commands have been configured.

The ifconfig is implemented by a C language function which has the following prototype:

int rtems_shell_rtems_main_ifconfig(
    int    argc,
    char **argv
);

The configuration structure for the ifconfig has the following prototype:

extern rtems_shell_cmd_t rtems_shell_IFCONFIG_Command;

This command is used to display and manipulate the routing table. When invoked with no arguments, the current routing information is displayed. When invoked with the subcommands add or del, then additional arguments must be provided to describe the route.

Command templates include the following:

route [add|del] -net IP_ADDRESS gw GATEWAY_ADDRESS [netmask MASK]
route [add|del] -host IP_ADDRESS gw GATEWAY_ADDRES [netmask MASK]

When not provided the netmask defaults to 255.255.255.0

The following is an example of how to use route to display, add, and delete a new route:

[/] $ route
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
default         192.168.1.14       UGS         0        0      0 eth1
192.168.1.0     255.255.255.0      U           0        0      1 eth1
192.168.1.14    00:A0:C8:1C:EE:28  UHL         1        0   1444 eth1
192.168.1.51    00:1D:7E:0C:D0:7C  UHL         0    10844   1202 eth1
192.168.1.151   00:1C:23:B2:0F:BB  UHL         2       37   1399 eth1
[/] $ route add -net 192.168.3.0 gw 192.168.1.14
[/] $ route
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
default         192.168.1.14       UGS         0        0      0 eth1
192.168.1.0     255.255.255.0      U           0        0      1 eth1
192.168.1.14    00:A0:C8:1C:EE:28  UHL         2        0   1498 eth1
192.168.1.51    00:1D:7E:0C:D0:7C  UHL         0    14937   1202 eth1
192.168.1.151   00:1C:23:B2:0F:BB  UHL         2       96   1399 eth1
192.168.3.0     192.168.1.14       UGS         0        0      0 eth1
[/] $ route del -net 192.168.3.0 gw 192.168.1.14
[/] $ route
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
default         192.168.1.14       UGS         0        0      0 eth1
192.168.1.0     255.255.255.0      U           0        0      1 eth1
192.168.1.14    00:A0:C8:1C:EE:28  UHL         1        0   1498 eth1
192.168.1.51    00:1D:7E:0C:D0:7C  UHL         0    15945   1202 eth1
192.168.1.151   00:1C:23:B2:0F:BB  UHL         2      117   1399 eth1

This command is included in the default shell command set. When building a custom command set, define CONFIGURE_SHELL_COMMAND_ROUTE to have this command included.

This command can be excluded from the shell command set by defining CONFIGURE_SHELL_NO_COMMAND_ROUTE when all shell commands have been configured.

The route is implemented by a C language function which has the following prototype:

int rtems_shell_rtems_main_route(
    int    argc,
    char **argv
);

The configuration structure for the route has the following prototype:

extern rtems_shell_cmd_t rtems_shell_ROUTE_Command;

The ping utility uses the ICMP protocol’s mandatory ECHO_REQUEST datagram to elicit an ICMP ECHO_RESPONSE from a host or gateway. ECHO_REQUEST datagrams (“pings”) have an IP and ICMP header, followed by a “struct timeval” and then an arbitrary number of “pad” bytes used to fill out the packet. The options are as follows:

-A

Audible. Output a bell (ASCII 0x07) character when no packet is received before the next packet is transmitted. To cater for round-trip times that are longer than the interval between transmissions, further missing packets cause a bell only if the maximum number of unreceived packets has increased.

-a

Audible. Include a bell (ASCII 0x07) character in the output when any packet is received. This option is ignored if other format options are present.

-c count

Stop after sending (and receiving) count ECHO_RESPONSE packets. If this option is not specified, ping will operate until interrupted. If this option is specified in conjunction with ping sweeps, each sweep will consist of count packets.

-D

Set the Don’t Fragment bit.

-d

Set the SO_DEBUG option on the socket being used.

-f

Flood ping. Outputs packets as fast as they come back or one hundred times per second, whichever is more. For every ECHO_REQUEST sent a period ”.” is printed, while for every ECHO_REPLY received a backspace is printed. This provides a rapid display of how many packets are being dropped. Only the super-user may use this option. This can be very hard on a network and should be used with caution.

-G sweepmaxsize

Specify the maximum size of ICMP payload when sending sweeping pings. This option is required for ping sweeps.

-g sweepminsize

Specify the size of ICMP payload to start with when sending sweeping pings. The default value is 0.

-h sweepincrsize

Specify the number of bytes to increment the size of ICMP payload after each sweep when sending sweeping pings. The default value is 1.

-I iface

Source multicast packets with the given interface address. This flag only applies if the ping destination is a multicast address.

-i wait

Wait wait seconds between sending each packet. The default is to wait for one second between each packet. The wait time may be fractional, but only the super-user may specify values less than 1 second. This option is incompatible with the -f option.

-L

Suppress loopback of multicast packets. This flag only applies if the ping destination is a multicast address.

-l preload

If preload is specified, ping sends that many packets as fast as possible before falling into its normal mode of behavior. Only the super-user may use this option.

-M mask | time

Use ICMP_MASKREQ or ICMP_TSTAMP instead of ICMP_ECHO. For mask, print the netmask of the remote machine. Set the net.inet.icmp.maskrepl MIB variable to enable ICMP_MASKREPLY. For time, print the origination, reception and transmission timestamps.

-m ttl

Set the IP Time To Live for outgoing packets. If not specified, the kernel uses the value of the net.inet.ip.ttl MIB variable.

-n

Numeric output only. No attempt will be made to lookup symbolic names for host addresses.

-o

Exit successfully after receiving one reply packet.

-p pattern

You may specify up to 16 “pad” bytes to fill out the packet you send. This is useful for diagnosing data-dependent problems in a network. For example, “-p ff” will cause the sent packet to be filled with all ones.

-Q

Somewhat quiet output. Don’t display ICMP error messages that are in response to our query messages. Originally, the -v flag was required to display such errors, but -v displays all ICMP error messages. On a busy machine, this output can be overbear- ing. Without the -Q flag, ping prints out any ICMP error mes- sages caused by its own ECHO_REQUEST messages.

-q

Quiet output. Nothing is displayed except the summary lines at startup time and when finished.

-R

Record route. Includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note that the IP header is only large enough for nine such routes; the traceroute(8) command is usually better at determining the route packets take to a particular destination. If more routes come back than should, such as due to an illegal spoofed packet, ping will print the route list and then truncate it at the correct spot. Many hosts ignore or discard the RECORD_ROUTE option.

-r

Bypass the normal routing tables and send directly to a host on an attached network. If the host is not on a directly-attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it (e.g., after the interface was dropped).

-S src_addr

Use the following IP address as the source address in outgoing packets. On hosts with more than one IP address, this option can be used to force the source address to be something other than the IP address of the interface the probe packet is sent on. If the IP address is not one of this machine’s interface addresses, an error is returned and nothing is sent.

-s packetsize

Specify the number of data bytes to be sent. The default is 56, which translates into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data. Only the super-user may specify val- ues more than default. This option cannot be used with ping sweeps.

-T ttl

Set the IP Time To Live for multicasted packets. This flag only applies if the ping destination is a multicast address.

-t timeout

Specify a timeout, in seconds, before ping exits regardless of how many packets have been received.

-v

Verbose output. ICMP packets other than ECHO_RESPONSE that are received are listed.

-W waittime

Time in milliseconds to wait for a reply for each packet sent. If a reply arrives later, the packet is not printed as replied, but considered as replied when calculating statistics.

-z tos

Use the specified type of service.

The ping utility exits with one of the following values:

0 At least one response was heard from the specified host.

2 The transmission was successful but no responses were

received.

any other value an error occurred. These values are defined in <sysexits.h>.

When using ping for fault isolation, it should first be run on the local host, to verify that the local network interface is up and running. Then, hosts and gateways further and further away should be “pinged”. Round-trip times and packet loss statistics are computed. If duplicate packets are received, they are not included in the packet loss calculation, although the round trip time of these packets is used in calculating the round-trip time statistics. When the specified number of packets have been sent a brief summary is displayed, showing the number of packets sent and received, and the minimum, mean, maximum, and standard deviation of the round-trip times.

This program is intended for use in network testing, measurement and management. Because of the load it can impose on the network, it is unwise to use ping during normal operations or from automated scripts.

This command can fail if more than the FD_SET size number of file descriptors are open.

The following is an example of how to use oing to ping:

[/] # ping 10.10.10.1
PING 10.10.10.1 (10.10.10.1): 56 data bytes
64 bytes from 10.10.10.1: icmp_seq=0 ttl=63 time=0.356 ms
64 bytes from 10.10.10.1: icmp_seq=1 ttl=63 time=0.229 ms
64 bytes from 10.10.10.1: icmp_seq=2 ttl=63 time=0.233 ms
64 bytes from 10.10.10.1: icmp_seq=3 ttl=63 time=0.235 ms
64 bytes from 10.10.10.1: icmp_seq=4 ttl=63 time=0.229 ms
--- 10.10.10.1 ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.229/0.256/0.356/0.050 ms
[/] # ping -f -c 10000  10.10.10.1
PING 10.10.10.1 (10.10.10.1): 56 data bytes
.
--- 10.10.10.1 ping statistics ---
10000 packets transmitted, 10000 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.154/0.225/0.533/0.027 ms

This command is included in the default shell command set. When building a custom command set, define CONFIGURE_SHELL_COMMAND_PING to have this command included.

This command can be excluded from the shell command set by defining CONFIGURE_SHELL_NO_COMMAND_PING when all shell commands have been configured.

The ping is implemented by a C language function which has the following prototype:

int rtems_shell_rtems_main_ping(
    int    argc,
    char **argv
);

The configuration structure for the ping has the following prototype:

extern rtems_shell_cmd_t rtems_shell_PING_Command;