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 (
    "context"
    "net"
    "net/netip"

    "git.frostfs.info/TrueCloudLab/multinet"
)

d, err := multinet.NewDialer(Config{
    Subnets:  []Subnet{
        {
            Prefix: netip.MustParsePrefix("10.11.70.0/23"),
            SourceIPs: []netip.Addr{
                netip.MustParseAddr("10.11.70.42"),
                netip.MustParseAddr("10.11.71.42"),
            },
        },
        {
            Prefix: netip.MustParsePrefix("192.168.123.0/24"),
            SourceIPs: []netip.Addr{
                netip.MustParseAddr("192.168.123.42"),
                netip.MustParseAddr("192.168.123.142"),
            },
        },
    },
    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
```