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wdenk68ceb292004-08-02 21:11:11 +00001
2In U-Boot, we implemented the networked console via the standard
3"devices" mechanism, which means that you can switch between the
4serial and network input/output devices by adjusting the 'stdin' and
5'stdout' environment variables. To switch to the networked console,
6set either of these variables to "nc". Input and output can be
7switched independently.
8
wdenkeedcd072004-09-08 22:03:11 +00009We use an environment variable 'ncip' to set the IP address and the
10port of the destination. The format is <ip_addr>:<port>. If <port> is
11omitted, the value of 6666 is used. If the env var doesn't exist, the
12broadcast address and port 6666 are used. If it is set to an IP
13address of 0 (or 0.0.0.0) then no messages are sent to the network.
14
wdenkb1bf6f22005-04-03 14:52:59 +000015For example, if your server IP is 192.168.1.1, you could use:
16
17 => setenv nc 'setenv stdout nc;setenv stdin nc'
18 => setenv ncip 192.168.1.1
19 => saveenv
20 => run nc
21
22
wdenk68ceb292004-08-02 21:11:11 +000023On the host side, please use this script to access the console:
24
Mike Frysingerbcb6dd92008-12-09 23:20:31 -050025 tools/netconsole <ip> [port]
wdenk68ceb292004-08-02 21:11:11 +000026
Mike Frysingerbcb6dd92008-12-09 23:20:31 -050027The script uses netcat to talk to the board over UDP. It requires you to
28specify the target IP address (or host name, assuming DNS is working). The
29script can be interrupted by pressing ^T (CTRL-T).
wdenkb1bf6f22005-04-03 14:52:59 +000030
Igor Marnat443feb72007-03-21 09:55:01 +030031Be aware that in some distributives (Fedora Core 5 at least)
32usage of nc has been changed and -l and -p options are considered
33as mutually exclusive. If nc complains about options provided,
34you can just remove the -p option from the script.
35
wdenk25d67122004-12-10 11:40:40 +000036It turns out that 'netcat' cannot be used to listen to broadcast
wdenkeedcd072004-09-08 22:03:11 +000037packets. We developed our own tool 'ncb' (see tools directory) that
38listens to broadcast packets on a given port and dumps them to the
39standard output. use it as follows:
40
41+++++++++++++++++++++++++++++++++++++++++++
42#! /bin/bash
43
wdenkb1bf6f22005-04-03 14:52:59 +000044[ $# = 1 ] || { echo "Usage: $0 target_ip" >&2 ; exit 1 ; }
45TARGET_IP=$1
46
wdenkeedcd072004-09-08 22:03:11 +000047stty icanon echo intr ^T
48./ncb &
wdenkb1bf6f22005-04-03 14:52:59 +000049nc -u ${TARGET_IP} 6666
wdenkeedcd072004-09-08 22:03:11 +000050stty icanon echo intr ^C
51kill 0
52+++++++++++++++++++++++++++++++++++++++++++
53
wdenkb1bf6f22005-04-03 14:52:59 +000054Again, this script takes exactly one argument, which is interpreted
55as the target IP address (or host name, assuming DNS is working). The
56script can be interrupted by pressing ^T (CTRL-T).
57
58The 'ncb' tool can be found in the tools directory; it will not be
59built by default so you will ither have to adjust the Makefile or
60build it manually.
61
62
wdenk68ceb292004-08-02 21:11:11 +000063For Linux, the network-based console needs special configuration.
64Minimally, the host IP address needs to be specified. This can be
65done either via the kernel command line, or by passing parameters
66while loading the netconsole.o module (when used in a loadable module
67configuration). Please refer to Documentation/networking/logging.txt
68file for the original Ingo Molnar's documentation on how to pass
69parameters to the loadable module.
70
71The format of the kernel command line parameter (for the static
72configuration) is as follows:
73
74 netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
75
76where
77
78 src-port source for UDP packets
79 (defaults to 6665)
80 src-ip source IP to use
81 (defaults to the interface's address)
82 dev network interface
83 (defaults to eth0)
84 tgt-port port for logging agent
85 (defaults to 6666)
86 tgt-ip IP address for logging agent
87 (this is the required parameter)
88 tgt-macaddr ethernet MAC address for logging agent
89 (defaults to broadcast)
90
91Examples:
92
93 netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
94
95or
96
97 netconsole=@/,@192.168.3.1/
98
99Please note that for the Linux networked console to work, the
100ethernet interface has to be up by the time the netconsole driver is
101initialized. This means that in case of static kernel configuration,
102the respective Ethernet interface has to be brought up using the "IP
103Autoconfiguration" kernel feature, which is usually done by defaults
104in the ELDK-NFS-based environment.
105
106To browse the Linux network console output, use the 'netcat' tool invoked
107as follows:
108
109 nc -u -l -p 6666
wdenk25d67122004-12-10 11:40:40 +0000110
111Note that unlike the U-Boot implementation the Linux netconsole is
112unidirectional, i. e. you have console output only in Linux.