wdenk | b8fb619 | 2004-08-02 21:11:11 +0000 | [diff] [blame] | 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 | |
wdenk | a0ebde5 | 2004-09-08 22:03:11 +0000 | [diff] [blame^] | 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 | |
wdenk | b8fb619 | 2004-08-02 21:11:11 +0000 | [diff] [blame] | 15 | On the host side, please use this script to access the console: |
| 16 | |
| 17 | +++++++++++++++++++++++++++++++++++++++++++ |
| 18 | #! /bin/bash |
| 19 | |
| 20 | TARGET_IP=$1 |
| 21 | |
| 22 | stty -icanon -echo intr ^T |
| 23 | nc -u -l -p 6666 < /dev/null & |
| 24 | nc -u ${TARGET_IP} 6666 |
| 25 | stty icanon echo intr ^C |
wdenk | a0ebde5 | 2004-09-08 22:03:11 +0000 | [diff] [blame^] | 26 | +++++++++++++++++++++++++++++++++++++++++++ |
| 27 | |
| 28 | It turned out that 'netcat' couldn't be used to listen to broadcast |
| 29 | packets. We developed our own tool 'ncb' (see tools directory) that |
| 30 | listens to broadcast packets on a given port and dumps them to the |
| 31 | standard output. use it as follows: |
| 32 | |
| 33 | +++++++++++++++++++++++++++++++++++++++++++ |
| 34 | #! /bin/bash |
| 35 | |
| 36 | stty icanon echo intr ^T |
| 37 | ./ncb & |
| 38 | nc -u mpc5200 6666 |
| 39 | stty icanon echo intr ^C |
| 40 | kill 0 |
wdenk | b8fb619 | 2004-08-02 21:11:11 +0000 | [diff] [blame] | 41 | +++++++++++++++++++++++++++++++++++++++++++ |
| 42 | |
| 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 |