feat: require bbr by default (#3774)

## Overview

This PR adds a requirement to use bbr by default. This requirement can
be bypassed by using a flag. Warnings are returned when installing, and
there is a makefile command that will configure the system to use bbr.


### ~~~ Note for Reviewers ~~~

Most of this PR is copying over the start command from the sdk.
Alternatively, we could simply modify the sdk. That would not require
copy past forking, but the trend has been that every change that we make
to the sdk eventually gets moved here, so I figured we should just skip
to doing that. This also gives us finer grained control in the future.
I'm definitely not tied to this approach, and if we'd rather change our
fork, then I'm happy go do that instead.

closes #3745

---------

Co-authored-by: Rootul P <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Makefile

@@ -31,7 +31,7 @@ build: mod
 .PHONY: build
 
 ## install: Build and install the celestia-appd binary into the $GOPATH/bin directory.
-install: go.sum
+install: go.sum check-bbr
 	@echo "--> Installing celestia-appd"
 	@go install $(BUILD_FLAGS) ./cmd/celestia-appd
 .PHONY: install
@@ -205,3 +205,28 @@ prebuilt-binary:
 		ghcr.io/goreleaser/goreleaser-cross:${GOLANG_CROSS_VERSION} \
 		release --clean
 .PHONY: prebuilt-binary
+
+## check-bbr: Check if your system uses BBR congestion control algorithm. Only works on Linux.
+check-bbr:
+	@echo "Checking if BBR is enabled..."
+	@if [ "$(sysctl net.ipv4.tcp_congestion_control | awk '{print $3}')" != "bbr" ]; then \
+	    echo "WARNING: BBR is not enabled. Please enable BBR for optimal performance. Call make enable-bbr or see Usage section in the README."; \
+	else \
+	    echo "BBR is enabled."; \
+	fi
+.PHONY: check-bbr
+
+## enable-bbr: Enable BBR congestion control algorithm. Only works on Linux.
+enable-bbr:
+	@echo "Configuring system to use BBR..."
+	@if [ "$(sysctl net.ipv4.tcp_congestion_control | awk '{print $3}')" != "bbr" ]; then \
+	    echo "BBR is not enabled. Configuring BBR..."; \
+	    sudo modprobe tcp_bbr; \
+	    echo "net.core.default_qdisc=fq" | sudo tee -a /etc/sysctl.conf; \
+	    echo "net.ipv4.tcp_congestion_control=bbr" | sudo tee -a /etc/sysctl.conf; \
+	    sudo sysctl -p; \
+	    echo "BBR has been enabled."; \
+	else \
+	    echo "BBR is already enabled."; \
+	fi
+.PHONY: enable-bbr

README.md

@@ -77,6 +77,22 @@ See <https://docs.celestia.org/nodes/celestia-app> for more information.
 
 ## Usage
 
+First, make sure that the [BBR](https://www.ietf.org/archive/id/draft-cardwell-iccrg-bbr-congestion-control-01.html) ("Bottleneck Bandwidth and Round-trip propagation time") congestion control algorithm is enabled in the
+system's kernel. The result should contain `bbr`:
+
+```sh
+sysctl net.ipv4.tcp_congestion_control
+```
+
+If not, enable it on Linux by calling the `make use-bbr` or by running:
+
+```sh
+sudo modprobe tcp_bbr
+net.core.default_qdisc=fq
+net.ipv4.tcp_congestion_control=bbr
+sudo sysctl -p
+```
+
 ```sh
 # Print help
 celestia-appd --help

cmd/celestia-appd/cmd/root.go

@@ -122,7 +122,7 @@ func initRootCommand(rootCommand *cobra.Command, encodingConfig encoding.Config)
 	)
 
 	// Add the following commands to the rootCommand: start, tendermint, export, version, and rollback.
-	server.AddCommands(rootCommand, app.DefaultNodeHome, NewAppServer, appExporter, addModuleInitFlags)
+	addCommands(rootCommand, app.DefaultNodeHome, NewAppServer, appExporter, addModuleInitFlags)
 }
 
 // setDefaultConsensusParams sets the default consensus parameters for the