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68ceb29e WD |
1 | |
2 | In U-Boot, we implemented the networked console via the standard | |
3 | "devices" mechanism, which means that you can switch between the | |
4 | serial and network input/output devices by adjusting the 'stdin' and | |
5 | 'stdout' environment variables. To switch to the networked console, | |
6 | set either of these variables to "nc". Input and output can be | |
7 | switched independently. | |
8 | ||
eedcd078 WD |
9 | We use an environment variable 'ncip' to set the IP address and the |
10 | port of the destination. The format is <ip_addr>:<port>. If <port> is | |
11 | omitted, the value of 6666 is used. If the env var doesn't exist, the | |
12 | broadcast address and port 6666 are used. If it is set to an IP | |
13 | address of 0 (or 0.0.0.0) then no messages are sent to the network. | |
14 | ||
b1bf6f2c WD |
15 | For 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 | ||
68ceb29e WD |
23 | On the host side, please use this script to access the console: |
24 | ||
bcb6dd91 | 25 | tools/netconsole <ip> [port] |
68ceb29e | 26 | |
bcb6dd91 MF |
27 | The script uses netcat to talk to the board over UDP. It requires you to |
28 | specify the target IP address (or host name, assuming DNS is working). The | |
29 | script can be interrupted by pressing ^T (CTRL-T). | |
b1bf6f2c | 30 | |
443feb74 IM |
31 | Be aware that in some distributives (Fedora Core 5 at least) |
32 | usage of nc has been changed and -l and -p options are considered | |
33 | as mutually exclusive. If nc complains about options provided, | |
34 | you can just remove the -p option from the script. | |
35 | ||
25d6712a | 36 | It turns out that 'netcat' cannot be used to listen to broadcast |
eedcd078 WD |
37 | packets. We developed our own tool 'ncb' (see tools directory) that |
38 | listens to broadcast packets on a given port and dumps them to the | |
1c20e4a9 MF |
39 | standard output. It will be built when compiling for a board which |
40 | has CONFIG_NETCONSOLE defined. If the netconsole script can find it | |
41 | in PATH or in the same directory, it will be used instead. | |
b1bf6f2c | 42 | |
68ceb29e WD |
43 | For Linux, the network-based console needs special configuration. |
44 | Minimally, the host IP address needs to be specified. This can be | |
45 | done either via the kernel command line, or by passing parameters | |
46 | while loading the netconsole.o module (when used in a loadable module | |
47 | configuration). Please refer to Documentation/networking/logging.txt | |
48 | file for the original Ingo Molnar's documentation on how to pass | |
49 | parameters to the loadable module. | |
50 | ||
51 | The format of the kernel command line parameter (for the static | |
52 | configuration) is as follows: | |
53 | ||
54 | netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] | |
55 | ||
56 | where | |
57 | ||
58 | src-port source for UDP packets | |
59 | (defaults to 6665) | |
60 | src-ip source IP to use | |
61 | (defaults to the interface's address) | |
62 | dev network interface | |
63 | (defaults to eth0) | |
64 | tgt-port port for logging agent | |
65 | (defaults to 6666) | |
66 | tgt-ip IP address for logging agent | |
67 | (this is the required parameter) | |
68 | tgt-macaddr ethernet MAC address for logging agent | |
69 | (defaults to broadcast) | |
70 | ||
71 | Examples: | |
72 | ||
73 | netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc | |
74 | ||
75 | or | |
76 | ||
77 | netconsole=@/,@192.168.3.1/ | |
78 | ||
79 | Please note that for the Linux networked console to work, the | |
80 | ethernet interface has to be up by the time the netconsole driver is | |
81 | initialized. This means that in case of static kernel configuration, | |
82 | the respective Ethernet interface has to be brought up using the "IP | |
83 | Autoconfiguration" kernel feature, which is usually done by defaults | |
84 | in the ELDK-NFS-based environment. | |
85 | ||
86 | To browse the Linux network console output, use the 'netcat' tool invoked | |
87 | as follows: | |
88 | ||
89 | nc -u -l -p 6666 | |
25d6712a WD |
90 | |
91 | Note that unlike the U-Boot implementation the Linux netconsole is | |
92 | unidirectional, i. e. you have console output only in Linux. |