Add bLIP 50: LSP Spec Transport Layer

The LSPS0 specification defines a protocol that is used for
communcations between LSP nodes and their clients. To this end it
utilizes a JSON-RPC format spoken over BOLT8 peer-to-peer messages.

The given protocol has been previously stabilized by the LSP
Spec group and is live in production with several LSP and client
implementations today.

As previously discussed on multiple occasions, the LSP Spec
group is however moving to a bLIP-centric process, which is why we
'upstream' these previously-stabilized specifications here.

Author: tnull

README.md

@@ -17,15 +17,15 @@ published here.
 For more detail on the process, please read [bLIP-0001](./blip-0001.md) and
 [bLIP-0002](./blip-0002.md).
 
-| Number                   | Title                          | Author                      | Status |
-|--------------------------|--------------------------------|-----------------------------|--------|
-| [1](./blip-0001.md)      | bLIP Process                   | Ryan Gentry                 | Active |
-| [2](./blip-0002.md)      | Reserved Values                | Bastien Teinturier          | Active |
-| [3](./blip-0003.md)      | Keysend                        | Valentine Wallace           | Active |
-| [4](./blip-0004.md)      | Experimental Endorsement       | Carla Kirk-Cohen            | Active |
-| [10](./blip-0010.md)     | Podcasting 2.0                 | Satoshis Stream             | Active |
-| [11](./blip-0011.md)     | NameDesc                       | Hampus Sjöberg              | Active |
-| [17](./blip-0017.md)     | Hosted Channels                | Anton Kumaigorodskiy        | Active |
-| [25](./blip-0025.md)     | Forward less than onion value  | Valentine Wallace           | Active |
-| [32](./blip-0032.md)     | Onion Message DNS Resolution   | Matt Corallo                | Active |
-
+| Number                   | Title                           | Author                      | Status |
+|--------------------------|---------------------------------|-----------------------------|--------|
+| [1](./blip-0001.md)      | bLIP Process                    | Ryan Gentry                 | Active |
+| [2](./blip-0002.md)      | Reserved Values                 | Bastien Teinturier          | Active |
+| [3](./blip-0003.md)      | Keysend                         | Valentine Wallace           | Active |
+| [4](./blip-0004.md)      | Experimental Endorsement        | Carla Kirk-Cohen            | Active |
+| [10](./blip-0010.md)     | Podcasting 2.0                  | Satoshis Stream             | Active |
+| [11](./blip-0011.md)     | NameDesc                        | Hampus Sjöberg              | Active |
+| [17](./blip-0017.md)     | Hosted Channels                 | Anton Kumaigorodskiy        | Active |
+| [25](./blip-0025.md)     | Forward less than onion value   | Valentine Wallace           | Active |
+| [32](./blip-0032.md)     | Onion Message DNS Resolution    | Matt Corallo                | Active |
+| [50](./blip-0050.md)     | LSPS0: LSP Spec Transport Layer | ZmnSCPxj jxPCSnmZ           | Active |

blip-0002.md

@@ -45,13 +45,14 @@ Custom feature bits used in the `I` [Bolt 11](https://github.com/lightning/bolts
 
 bLIPs may reserve feature bits by adding them to the following table:
 
-| Bits    | Name                  | Description                                                | Context | Dependencies            | Link                      |
-|---------|-----------------------|------------------------------------------------------------|---------|-------------------------|---------------------------|
-| 54/55   | `keysend`             | A form of spontaneous payment                              | N       | `var_onion_optin`       | [bLIP 3](./blip-0003.md)  |
-| 256/257 | `hosted_channels`     | This node accepts requests for hosted channels             | IN      |                         | [bLIP 17](./blip-0017.md) |
-| 258/259 | `dns_resolver`        | This node accepts DNSSEC proof requests                    | N       |                         | [bLIP 32](./blip-0032.md) |
-| 260/261 | `htlc_endorsement`    | This node forwards experimental htlc endorsement signals   | N       |                         | [bLIP 4](./blip-004.md)   |
-| 262/263 | `bolt11_blinded_path` | This invoice may contain a new blinded path tagged field   | I       | `option_route_blinding` | [bLIP 39](./blip-0039.md) |
+| Bits    | Name                   | Description                                                | Context | Dependencies            | Link                      |
+|---------|------------------------|------------------------------------------------------------|---------|-------------------------|---------------------------|
+| 54/55   | `keysend`              | A form of spontaneous payment                              | N       | `var_onion_optin`       | [bLIP 3](./blip-0003.md)  |
+| 256/257 | `hosted_channels`      | This node accepts requests for hosted channels             | IN      |                         | [bLIP 17](./blip-0017.md) |
+| 258/259 | `dns_resolver`         | This node accepts DNSSEC proof requests                    | N       |                         | [bLIP 32](./blip-0032.md) |
+| 260/261 | `htlc_endorsement`     | This node forwards experimental htlc endorsement signals   | N       |                         | [bLIP 4](./blip-004.md)   |
+| 262/263 | `bolt11_blinded_path`  | This invoice may contain a new blinded path tagged field   | I       | `option_route_blinding` | [bLIP 39](./blip-0039.md) |
+| 729     | `option_supports_lsps` | This node supports LSPS protocol(s)                        | IN      |                         | [bLIP 50](./blip-0050.md) |
 
 ### Messages
 
@@ -63,6 +64,7 @@ bLIPs may create new messages and reserve their type in the following table:
 
 | Type    | Name                            | Link                       |
 | ------- | ------------------------------- | -------------------------- |
+| 37913   | `lsps0_message_id`              | [bLIP 50](./blip-0050.md)  |
 | 65535   | `invoke_hosted_channel`         | [bLIP 17](./blip-0017.md)  |
 | 65533   | `init_hosted_channel`           | [bLIP 17](./blip-0017.md)  |
 | 65531   | `last_cross_signed_state`       | [bLIP 17](./blip-0017.md)  |