multinet/README.md

# Source-based routing in Golang


Consider this routing table:
```
10.11.70.0/23 dev data0 proto kernel scope link src 10.11.70.42
10.11.70.0/23 dev data1 proto kernel scope link src 10.11.71.42
192.168.123.0/24 dev internal0 proto kernel scope link src 192.168.123.42
192.168.123.0/24 dev internal1 proto kernel scope link src 192.168.123.142
```

Simple `net.Dial` to either `10.11.70.42` or `10.11.71.42` will match the first subnet and be routed via data0.
This problems is usually solved by bonds.
But sometimes you need to invent a bicycle.

## Usage

```golang
import "git.frostfs.info/TrueCloudLab/multinet"

d, err := multinet.NewDialer(Config{
    Subnets:  []string{"10.11.70.0/23", "192.168.123.0/24"},
    Balancer: multinet.BalancerTypeRoundRobin,
})
if err != nil {
    // handle error
}

conn, err := d.DialContext(ctx, "tcp", "10.11.70.42")
if err != nil {
    // handle error
}
// do stuff
```

### Updating interface state

`Multidialer` exposes `UpdateInterface()` method for updating state of a single link.
`NetlinkWatcher` can wrap `Multidialer` type and perform all updates automatically.

TODO: describe needed capabilities here.

## Patch

To perform refactoring (use `multinet.Dial` instead of `net.Dial`) using [gopatch](https://github.com/uber-go/gopatch):

```bash
gopatch -p ./multinet.patch <project directory>
```