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|
package gateway
import (
"context"
"crypto/ed25519"
"crypto/tls"
"crypto/x509"
_ "embed"
"errors"
"io"
"log"
"net"
"os"
"sync"
"time"
tea "github.com/charmbracelet/bubbletea"
"github.com/kyren223/eko/internal/packet"
"github.com/kyren223/eko/pkg/assert"
)
//go:embed server.crt
var certPEM []byte
var (
tlsConfig *tls.Config
asyncResponses []chan packet.Payload
responsesMu sync.Mutex
connection net.Conn
connMu sync.Mutex
)
func init() {
certPool := x509.NewCertPool()
if !certPool.AppendCertsFromPEM(certPEM) {
log.Fatalln("failed to append server certificate")
}
tlsConfig = &tls.Config{
RootCAs: certPool,
ServerName: "localhost",
}
}
func Connect(ctx context.Context, program *tea.Program, privKey ed25519.PrivateKey) {
conn, err := tls.Dial("tcp4", ":7223", tlsConfig)
if err != nil {
assert.NoError(err, "TODO handle error")
}
log.Println("established connection with server")
if err := handleAuth(ctx, conn, privKey); err != nil {
assert.NoError(err, "TODO handle error")
}
log.Println("successfully authenticated with server")
framer := packet.NewFramer(ctx)
go func() {
connection = conn
handleConnection(ctx, conn, framer)
close(framer.Out)
conn.Close()
connection = nil
}()
go handlePacketStream(framer, program)
}
func handleAuth(ctx context.Context, conn net.Conn, privKey ed25519.PrivateKey) error {
const nonceSize = 32
challengeRequest := make([]byte, 1+nonceSize)
err := conn.SetDeadline(time.Now().Add(10 * time.Second))
assert.NoError(err, "setting deadline should not error")
defer func() {
err := conn.SetDeadline(time.Time{})
assert.NoError(err, "unsetting deadline should not error")
}()
bytesRead := 0
for bytesRead < 1+nonceSize {
n, err := conn.Read(challengeRequest[bytesRead:])
if err != nil {
return err
}
bytesRead += n
}
assert.Assert(challengeRequest[0] == packet.VERSION, "client should always have the same version as the server")
challengeResponse := make([]byte, 1+ed25519.PublicKeySize+ed25519.SignatureSize)
challengeResponse[0] = packet.VERSION
copy(challengeResponse[1:1+ed25519.PublicKeySize], privKey.Public().(ed25519.PublicKey))
signedNonce := ed25519.Sign(privKey, challengeRequest[1:])
n := copy(challengeResponse[1+ed25519.PublicKeySize:], signedNonce)
assert.Assert(n == ed25519.SignatureSize, "copy should've copied the entire signature exactly")
_, err = conn.Write(challengeResponse)
if err != nil {
return err
}
return nil
}
func handleConnection(ctx context.Context, conn net.Conn, framer packet.PacketFramer) {
buffer := make([]byte, 512)
for {
err := conn.SetReadDeadline(time.Now().Add(time.Second))
assert.NoError(err, "setting a read deadline should not error")
n, err := conn.Read(buffer)
deadlineExceeded := errors.Is(err, os.ErrDeadlineExceeded)
if err != nil && !deadlineExceeded {
if !errors.Is(err, io.EOF) {
log.Println("read error:", err)
}
break
}
if ctx.Err() != nil {
log.Println("context error:", ctx.Err())
break
}
err = framer.Push(ctx, buffer[:n])
if ctx.Err() != nil {
log.Println("context error:", ctx.Err())
break
}
assert.NoError(err, "packets from server should always be correct")
}
}
func handlePacketStream(framer packet.PacketFramer, program *tea.Program) {
for {
pkt, ok := <-framer.Out
if !ok {
break
}
payload, err := pkt.DecodedPayload()
assert.NoError(err, "server should always provide a decodeable packet")
if pkt.Type().IsPush() {
log.Println("received streamed packet:", payload)
program.Send(payload)
continue
}
responsesMu.Lock()
assert.Assert(len(asyncResponses) != 0, "there must always be at least 1 response waiting")
responseChan := asyncResponses[0]
copy(asyncResponses, asyncResponses[1:])
asyncResponses = asyncResponses[:len(asyncResponses)-1]
responsesMu.Unlock()
go func() {
responseChan <- payload
}()
}
}
func conn() net.Conn {
return connection
}
func Send(request packet.Payload) <-chan packet.Payload {
responseChan := make(chan packet.Payload)
go func() {
pkt := packet.NewPacket(packet.NewMsgPackEncoder(request))
conn := conn()
if conn == nil {
log.Println("request send error:", "connection is closed")
close(responseChan)
return
}
connMu.Lock()
errDeadline := conn.SetWriteDeadline(time.Now().Add(5 * time.Second))
assert.NoError(errDeadline, "setting a write deadline should not error")
_, err := pkt.Into(conn)
errDeadline = conn.SetWriteDeadline(time.Time{})
assert.NoError(errDeadline, "setting a write deadline should not error")
connMu.Unlock()
if err != nil {
log.Println("request send error:", err)
close(responseChan)
return
}
responsesMu.Lock()
asyncResponses = append(asyncResponses, responseChan)
responsesMu.Unlock()
time.Sleep(5 * time.Second)
responsesMu.Lock()
index := -1
for i, ch := range asyncResponses {
if ch == responseChan {
index = i
}
}
if index != -1 {
copy(asyncResponses[index:], asyncResponses[index+1:])
asyncResponses = asyncResponses[:len(asyncResponses)-1]
close(responseChan)
}
responsesMu.Unlock()
}()
return responseChan
}
|
