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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
25+++++++++++++++++++++++++++++++++++++++++++
26#! /bin/bash
27
wdenkb1bf6f22005-04-03 14:52:59 +000028[ $# = 1 ] || { echo "Usage: $0 target_ip" >&2 ; exit 1 ; }
wdenk68ceb292004-08-02 21:11:11 +000029TARGET_IP=$1
30
31stty -icanon -echo intr ^T
32nc -u -l -p 6666 < /dev/null &
33nc -u ${TARGET_IP} 6666
34stty icanon echo intr ^C
35+++++++++++++++++++++++++++++++++++++++++++
36
wdenkb1bf6f22005-04-03 14:52:59 +000037The script expects exactly one argument, which is interpreted as the
38target IP address (or host name, assuming DNS is working). The script
39can be interrupted by pressing ^T (CTRL-T).
40
wdenk25d67122004-12-10 11:40:40 +000041It turns out that 'netcat' cannot be used to listen to broadcast
wdenkeedcd072004-09-08 22:03:11 +000042packets. We developed our own tool 'ncb' (see tools directory) that
43listens to broadcast packets on a given port and dumps them to the
44standard output. use it as follows:
45
46+++++++++++++++++++++++++++++++++++++++++++
47#! /bin/bash
48
wdenkb1bf6f22005-04-03 14:52:59 +000049[ $# = 1 ] || { echo "Usage: $0 target_ip" >&2 ; exit 1 ; }
50TARGET_IP=$1
51
wdenkeedcd072004-09-08 22:03:11 +000052stty icanon echo intr ^T
53./ncb &
wdenkb1bf6f22005-04-03 14:52:59 +000054nc -u ${TARGET_IP} 6666
wdenkeedcd072004-09-08 22:03:11 +000055stty icanon echo intr ^C
56kill 0
57+++++++++++++++++++++++++++++++++++++++++++
58
wdenkb1bf6f22005-04-03 14:52:59 +000059Again, this script takes exactly one argument, which is interpreted
60as the target IP address (or host name, assuming DNS is working). The
61script can be interrupted by pressing ^T (CTRL-T).
62
63The 'ncb' tool can be found in the tools directory; it will not be
64built by default so you will ither have to adjust the Makefile or
65build it manually.
66
67
wdenk68ceb292004-08-02 21:11:11 +000068For Linux, the network-based console needs special configuration.
69Minimally, the host IP address needs to be specified. This can be
70done either via the kernel command line, or by passing parameters
71while loading the netconsole.o module (when used in a loadable module
72configuration). Please refer to Documentation/networking/logging.txt
73file for the original Ingo Molnar's documentation on how to pass
74parameters to the loadable module.
75
76The format of the kernel command line parameter (for the static
77configuration) is as follows:
78
79 netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
80
81where
82
83 src-port source for UDP packets
84 (defaults to 6665)
85 src-ip source IP to use
86 (defaults to the interface's address)
87 dev network interface
88 (defaults to eth0)
89 tgt-port port for logging agent
90 (defaults to 6666)
91 tgt-ip IP address for logging agent
92 (this is the required parameter)
93 tgt-macaddr ethernet MAC address for logging agent
94 (defaults to broadcast)
95
96Examples:
97
98 netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
99
100or
101
102 netconsole=@/,@192.168.3.1/
103
104Please note that for the Linux networked console to work, the
105ethernet interface has to be up by the time the netconsole driver is
106initialized. This means that in case of static kernel configuration,
107the respective Ethernet interface has to be brought up using the "IP
108Autoconfiguration" kernel feature, which is usually done by defaults
109in the ELDK-NFS-based environment.
110
111To browse the Linux network console output, use the 'netcat' tool invoked
112as follows:
113
114 nc -u -l -p 6666
wdenk25d67122004-12-10 11:40:40 +0000115
116Note that unlike the U-Boot implementation the Linux netconsole is
117unidirectional, i. e. you have console output only in Linux.