nvram-cfg-parser

Command line parser for Tomato Firmware NVRAM cfg backups

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Decodes Tomato cfg files into JSON so they can be changed and compared against other backups. Encodes JSON-formatted Tomato cfg key/value pairs into the Tomato cfg format.

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nvram-cfg-parser is available from npm, the standard package manager included with nodejs.

Install from npm:

# npm install -g nvram-cfg-parser

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#### decode

nvramcfg decode

Command example:

$ nvramcfg decode tomato_v128_m943394.cfg

Output example (keys in no particular order):

``json
{
"0|31|||word text\n^begins-with.domain.\n.ends-with.net$\n^www.exact-domain.net$|0|exampl": "|1320|300|31|||word text\n^begins-with.domain.\n.ends-with.net$\n^www.exact-domain.net$|0|example",
"wl_mac_deny": "",
"wl_radius_port": "1812",
"sb/1/ofdm2gpo": "0x44444444",
"pptp_client_mru": "1450",
"https_crt": "",
"qos_reset": "1",
...
`

#### decode to file

$ nvramcfg decode tomato_v128_m943394.cfg > tomato_v128_m943394.json

#### encode

nvramcfg encode

Command example:

$ nvramcfg encode arm tomato_v128_m943394-altered.json > tomato_v128_m943394-altered.cfg

Supported formats are original and arm.


#### colorized json diff

nvramcfg diff

Command example:

$ nvramcfg diff tomato_v128_m943394.json tomato_v128_m943394-altered.json

Output example

`diff
{
- router_name: "TomatoUSB"
+ router_name: "ExampleName"
}
`

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#### Original

The tomato_vxxx_xxxxx.cfg files are gzipped utf-8 text with null characters bounding and separating the key=value pair sets. We unzip the file, strip the header and footer, and read the null-separated key=value pairs.

#### ARM

The tomato_vxxx_xxxxx.cfg files are not gzipped, but are an obfuscated version of the original utf-8-with-null-separators. We read the random value and de-obfuscate back to the original format.

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Decode and encode are available from the NvramParser class. See comments in src/nvram-parser.iced, src/nvram-arm-parser.iced, for details.

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* How to tell if my router build is ARM format?

The tomato builds for your router contain ARM in the filename. Example: tomato-RT-AC56U-AT-ARM-2.7-128-AIO-64K.trx`

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MIT Licensed. Use at your own risk.