Added a (rough) roadmap to resolving a number of known issues

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Samuel Hawksby-Robinson 2023-08-12 14:32:39 +01:00
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# Local Pairing To-dos
- [Network Address / Peer Discovery](#network-address--peer-discovery)
- [Network Debug Diagnostics](#network-debug-diagnostics)
## Network Address / Peer Discovery
Revamp the preferred network discovery process
Note this functionality is pre-secret share so doesn't ...
- **Pre-shared secret: scan the QR code first, containing the secret and then attempt to discover the other device(s)**
- ⚠️ **Problem:** Only works if UDP discovery works. [See possible solution for UDP discovery failure mitigation](#udp-discovery-failure-mitigation)
- Start pairing server on relevant device, listen to `0.0.0.0`.
- get selected port number
- get TLS pub key
- get secret
- Scan QR code which including:
- selected port number
- TLS pub key
- secret
- UDP discovery happens 🧙🪄✨
- devices acquire ip addresses of peer(s), and themselves.
- client device attempts connection as normal
- **Post-shared secret, which is confirmed later with the QR code**
- UDP discovery happens 🧙🪄✨
- devices acquire ip addresses of peer(s), and themselves.
- can also optionally give feedback to the user with the pairing options.
- server device starts server listener, listen to known network ip address
- get selected port number
- get TLS pub key
- get secret
- Scan QR code which including:
- selected port number
- TLS pub key
- secret
- client device attempts connection as normal
### Self IP address acquisition
1. Ask network interface for its preferred outbound IP address
- The process currently relied on
- Add a required a self "confirmation" ping, to ensure the given address is network addressable.
- On fail, fall through to stage 2
2. device gets a list of its network addresses.
- Use `netIfaces, err := net.Interfaces()` [See snippet](#get-all-network-addresses)
- run filter for only local private net addrs
- open listener on 0.0.0.0
- make an outbound network call to all ips
- call should include the addressing ip so device knows which address is network addressable
- record all ip addresses that are able to ping the listener.
- hopefully the list will only ever contain 1 IP address
- On fail, fall through to stage 3
3. Attempt discovery via UDP multicast
- **Question :** How do **both** devices know when to start UDP discovery?
- Perhaps the QR code device can add details to the application
- no guarantee that both devices get an IP address
- [See UDP discovery failure mitigation](#udp-discovery-failure-mitigation)
## Network Debug Diagnostics
We need to check a few things if a connection isn't working
- What network ip address does the device think it has?
- What is the port number the listener is listening on?
- Can the device access its own network IP address?
- Can a device find, and be found by, other devices?
- attempt UDP discovery
- What is the device's network connection(s) status?
- `ipconfig` / `ifconfig`
- Test each in series, all above functions
- Capture everything, even errors
- DO NOT early return errors, log the errors, proceed with the next function.
- log all outputs to standard logger
- log all outputs memory for export / return
- When test suite is complete return log out put
## Refs
###### UDP discovery failure mitigation
- Both devices listen on a tcp port chosen by the network interface
- Attempt UDP discovery
- In the UDP packet include:
- the device's listener port number
- ensure the notifier's id is stored for later connections via tcp
- When peer A discovers peer B, peer A pings peer B's "confirmation" listener with peer B's IP address and network info about peer A
- peer B attempts an outbound **TLS** connection to its own "confirmation" server, with a random code, to confirm its own IP address.
###### Get all network addresses
```go
package test
import (
"fmt"
"net"
)
func AllNetworkAddresses() error {
netIfaces, err := net.Interfaces()
if err != nil {
return err
}
for _, i := range netIfaces {
addrs, err := i.Addrs()
if err != nil {
return err
}
for _, addr := range addrs {
var ip net.IP
switch v := addr.(type) {
case *net.IPNet:
ip = v.IP
case *net.IPAddr:
ip = v.IP
default:
return fmt.Errorf("unknown ip type %s", v)
}
fmt.Print(ip)
}
}
return nil
}
```