README.NetConsole 3.4 KB

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  1. In U-Boot, we implemented the networked console via the standard
  2. "devices" mechanism, which means that you can switch between the
  3. serial and network input/output devices by adjusting the 'stdin' and
  4. 'stdout' environment variables. To switch to the networked console,
  5. set either of these variables to "nc". Input and output can be
  6. switched independently.
  7. We use an environment variable 'ncip' to set the IP address and the
  8. port of the destination. The format is <ip_addr>:<port>. If <port> is
  9. omitted, the value of 6666 is used. If the env var doesn't exist, the
  10. broadcast address and port 6666 are used. If it is set to an IP
  11. address of 0 (or 0.0.0.0) then no messages are sent to the network.
  12. For example, if your server IP is 192.168.1.1, you could use:
  13. => setenv nc 'setenv stdout nc;setenv stdin nc'
  14. => setenv ncip 192.168.1.1
  15. => saveenv
  16. => run nc
  17. On the host side, please use this script to access the console:
  18. tools/netconsole <ip> [port]
  19. The script uses netcat to talk to the board over UDP. It requires you to
  20. specify the target IP address (or host name, assuming DNS is working). The
  21. script can be interrupted by pressing ^T (CTRL-T).
  22. Be aware that in some distributives (Fedora Core 5 at least)
  23. usage of nc has been changed and -l and -p options are considered
  24. as mutually exclusive. If nc complains about options provided,
  25. you can just remove the -p option from the script.
  26. It turns out that 'netcat' cannot be used to listen to broadcast
  27. packets. We developed our own tool 'ncb' (see tools directory) that
  28. listens to broadcast packets on a given port and dumps them to the
  29. standard output. It will be built when compiling for a board which
  30. has CONFIG_NETCONSOLE defined. If the netconsole script can find it
  31. in PATH or in the same directory, it will be used instead.
  32. For Linux, the network-based console needs special configuration.
  33. Minimally, the host IP address needs to be specified. This can be
  34. done either via the kernel command line, or by passing parameters
  35. while loading the netconsole.o module (when used in a loadable module
  36. configuration). Please refer to Documentation/networking/logging.txt
  37. file for the original Ingo Molnar's documentation on how to pass
  38. parameters to the loadable module.
  39. The format of the kernel command line parameter (for the static
  40. configuration) is as follows:
  41. netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
  42. where
  43. src-port source for UDP packets
  44. (defaults to 6665)
  45. src-ip source IP to use
  46. (defaults to the interface's address)
  47. dev network interface
  48. (defaults to eth0)
  49. tgt-port port for logging agent
  50. (defaults to 6666)
  51. tgt-ip IP address for logging agent
  52. (this is the required parameter)
  53. tgt-macaddr ethernet MAC address for logging agent
  54. (defaults to broadcast)
  55. Examples:
  56. netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
  57. or
  58. netconsole=@/,@192.168.3.1/
  59. Please note that for the Linux networked console to work, the
  60. ethernet interface has to be up by the time the netconsole driver is
  61. initialized. This means that in case of static kernel configuration,
  62. the respective Ethernet interface has to be brought up using the "IP
  63. Autoconfiguration" kernel feature, which is usually done by defaults
  64. in the ELDK-NFS-based environment.
  65. To browse the Linux network console output, use the 'netcat' tool invoked
  66. as follows:
  67. nc -u -l -p 6666
  68. Note that unlike the U-Boot implementation the Linux netconsole is
  69. unidirectional, i. e. you have console output only in Linux.