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faucet: with mainnet balance check, 0.002BNB at least (bnb-chain#2672)
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@zzzckck
zzzckck authored Sep 4, 2024
1 parent f85d19a commit 5c4096f
Showing 1 changed file with 113 additions and 78 deletions.
191 changes: 113 additions & 78 deletions cmd/faucet/faucet.go
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Original file line number Diff line number Diff line change
Expand Up @@ -53,9 +53,10 @@ import (
)

var (
genesisFlag = flag.String("genesis", "", "Genesis json file to seed the chain with")
apiPortFlag = flag.Int("apiport", 8080, "Listener port for the HTTP API connection")
wsEndpoint = flag.String("ws", "http://127.0.0.1:7777/", "Url to ws endpoint")
genesisFlag = flag.String("genesis", "", "Genesis json file to seed the chain with")
apiPortFlag = flag.Int("apiport", 8080, "Listener port for the HTTP API connection")
wsEndpoint = flag.String("ws", "http://127.0.0.1:7777/", "Url to ws endpoint")
wsEndpointMainnet = flag.String("ws.mainnet", "", "Url to ws endpoint of BSC mainnet")

netnameFlag = flag.String("faucet.name", "", "Network name to assign to the faucet")
payoutFlag = flag.Int("faucet.amount", 1, "Number of Ethers to pay out per user request")
Expand All @@ -82,6 +83,7 @@ var (
resendBatchSize = 3
resendMaxGasPrice = big.NewInt(50 * params.GWei)
wsReadTimeout = 5 * time.Minute
minMainnetBalance = big.NewInt(2 * 1e6 * params.GWei) // 0.002 bnb
)

var (
Expand All @@ -92,11 +94,17 @@ var (
//go:embed faucet.html
var websiteTmpl string

func weiToEtherStringFx(wei *big.Int, prec int) string {
etherValue := new(big.Float).Quo(new(big.Float).SetInt(wei), big.NewFloat(params.Ether))
// Format the big.Float directly to a string with the specified precision
return etherValue.Text('f', prec)
}

func main() {
// Parse the flags and set up the logger to print everything requested
flag.Parse()
log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.FromLegacyLevel(*logFlag), true)))

log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.FromLegacyLevel(*logFlag), false)))
log.Info("faucet started")
// Construct the payout tiers
amounts := make([]string, *tiersFlag)
for i := 0; i < *tiersFlag; i++ {
Expand Down Expand Up @@ -175,7 +183,7 @@ func main() {
log.Crit("Failed to unlock faucet signer account", "err", err)
}
// Assemble and start the faucet light service
faucet, err := newFaucet(genesis, *wsEndpoint, ks, website.Bytes(), bep2eInfos)
faucet, err := newFaucet(genesis, *wsEndpoint, *wsEndpointMainnet, ks, website.Bytes(), bep2eInfos)
if err != nil {
log.Crit("Failed to start faucet", "err", err)
}
Expand All @@ -202,9 +210,10 @@ type bep2eInfo struct {

// faucet represents a crypto faucet backed by an Ethereum light client.
type faucet struct {
config *params.ChainConfig // Chain configurations for signing
client *ethclient.Client // Client connection to the Ethereum chain
index []byte // Index page to serve up on the web
config *params.ChainConfig // Chain configurations for signing
client *ethclient.Client // Client connection to the Ethereum chain
clientMainnet *ethclient.Client // Client connection to BSC mainnet for balance check
index []byte // Index page to serve up on the web

keystore *keystore.KeyStore // Keystore containing the single signer
account accounts.Account // Account funding user faucet requests
Expand Down Expand Up @@ -233,7 +242,7 @@ type wsConn struct {
wlock sync.Mutex
}

func newFaucet(genesis *core.Genesis, url string, ks *keystore.KeyStore, index []byte, bep2eInfos map[string]bep2eInfo) (*faucet, error) {
func newFaucet(genesis *core.Genesis, url string, mainnetUrl string, ks *keystore.KeyStore, index []byte, bep2eInfos map[string]bep2eInfo) (*faucet, error) {
bep2eAbi, err := abi.JSON(strings.NewReader(bep2eAbiJson))
if err != nil {
return nil, err
Expand All @@ -242,6 +251,11 @@ func newFaucet(genesis *core.Genesis, url string, ks *keystore.KeyStore, index [
if err != nil {
return nil, err
}
clientMainnet, err := ethclient.Dial(mainnetUrl)
if err != nil {
// skip mainnet balance check if it there is no available mainnet endpoint
log.Warn("dail mainnet endpoint failed", "mainnetUrl", mainnetUrl, "err", err)
}

// Allow 1 request per minute with burst of 5, and cache up to 1000 IPs
limiter, err := NewIPRateLimiter(rate.Limit(1.0), 5, 1000)
Expand All @@ -250,16 +264,17 @@ func newFaucet(genesis *core.Genesis, url string, ks *keystore.KeyStore, index [
}

return &faucet{
config: genesis.Config,
client: client,
index: index,
keystore: ks,
account: ks.Accounts()[0],
timeouts: make(map[string]time.Time),
update: make(chan struct{}, 1),
bep2eInfos: bep2eInfos,
bep2eAbi: bep2eAbi,
limiter: limiter,
config: genesis.Config,
client: client,
clientMainnet: clientMainnet,
index: index,
keystore: ks,
account: ks.Accounts()[0],
timeouts: make(map[string]time.Time),
update: make(chan struct{}, 1),
bep2eInfos: bep2eInfos,
bep2eAbi: bep2eAbi,
limiter: limiter,
}, nil
}

Expand Down Expand Up @@ -387,7 +402,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) {
// if user did not give response for too long, then the routine will be stuck.
conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
if err = conn.ReadJSON(&msg); err != nil {
log.Info("read json message failed", "err", err, "ip", ip)
log.Debug("read json message failed", "err", err, "ip", ip)
return
}
if !*noauthFlag && !strings.HasPrefix(msg.URL, "https://twitter.com/") && !strings.HasPrefix(msg.URL, "https://www.facebook.com/") {
Expand All @@ -407,7 +422,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) {
}
log.Info("Faucet funds requested", "url", msg.URL, "tier", msg.Tier, "ip", ip)

// If captcha verifications are enabled, make sure we're not dealing with a robot
// check #1: captcha verifications to exclude robot
if *captchaToken != "" {
form := url.Values{}
form.Add("secret", *captchaSecret)
Expand Down Expand Up @@ -484,88 +499,108 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) {
}
continue
}
log.Info("Faucet request valid", "url", msg.URL, "tier", msg.Tier, "user", username, "address", address, "ip", ip)

// Ensure the user didn't request funds too recently
// check #2: check IP and ID(address) to ensure the user didn't request funds too recently,
f.lock.Lock()
var (
fund bool
timeout time.Time
)

if ipTimeout := f.timeouts[ips[len(ips)-2]]; time.Now().Before(ipTimeout) {
f.lock.Unlock()
if err = sendError(wsconn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(time.Until(ipTimeout)))); err != nil { // nolint: gosimple
log.Warn("Failed to send funding error to client", "err", err)
return
}
log.Info("too frequent funding(ip)", "TimeLeft", common.PrettyDuration(time.Until(ipTimeout)), "ip", ips[len(ips)-2], "ipsStr", ipsStr)
continue
}
if idTimeout := f.timeouts[id]; time.Now().Before(idTimeout) {
f.lock.Unlock()
// Send an error if too frequent funding, otherwise a success
if err = sendError(wsconn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(time.Until(idTimeout)))); err != nil { // nolint: gosimple
log.Warn("Failed to send funding error to client", "err", err)
return
}
log.Info("too frequent funding(id)", "TimeLeft", common.PrettyDuration(time.Until(idTimeout)), "id", id)
continue
}

if timeout = f.timeouts[id]; time.Now().After(timeout) {
var tx *types.Transaction
if msg.Symbol == "BNB" {
// User wasn't funded recently, create the funding transaction
amount := new(big.Int).Div(new(big.Int).Mul(big.NewInt(int64(*payoutFlag)), ether), big.NewInt(10))
amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil))
amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil))

tx = types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil)
// check #3: minimum mainnet balance check, internal error will bypass the check to avoid blocking the faucet service
if f.clientMainnet != nil {
mainnetAddr := address
balanceMainnet, err := f.clientMainnet.BalanceAt(context.Background(), mainnetAddr, nil)
if err != nil {
log.Warn("check balance failed, call BalanceAt", "err", err)
} else if balanceMainnet == nil {
log.Warn("check balance failed, balanceMainnet is nil")
} else {
tokenInfo, ok := f.bep2eInfos[msg.Symbol]
if !ok {
if balanceMainnet.Cmp(minMainnetBalance) < 0 {
f.lock.Unlock()
log.Warn("Failed to find symbol", "symbol", msg.Symbol)
continue
}
input, err := f.bep2eAbi.Pack("transfer", address, &tokenInfo.Amount)
if err != nil {
f.lock.Unlock()
log.Warn("Failed to pack transfer transaction", "err", err)
log.Warn("insufficient BNB on BSC mainnet", "address", mainnetAddr,
"balanceMainnet", balanceMainnet, "minMainnetBalance", minMainnetBalance)
// Send an error if failed to meet the minimum balance requirement
if err = sendError(wsconn, fmt.Errorf("insufficient BNB on BSC mainnet (require >=%sBNB)",
weiToEtherStringFx(minMainnetBalance, 3))); err != nil {
log.Warn("Failed to send mainnet minimum balance error to client", "err", err)
return
}
continue
}
tx = types.NewTransaction(f.nonce+uint64(len(f.reqs)), tokenInfo.Contract, nil, 420000, f.price, input)
}
signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainID)
if err != nil {
}
log.Info("Faucet request valid", "url", msg.URL, "tier", msg.Tier, "user", username, "address", address, "ip", ip)

// now, it is ok to send tBNB or other tokens
var tx *types.Transaction
if msg.Symbol == "BNB" {
// User wasn't funded recently, create the funding transaction
amount := new(big.Int).Div(new(big.Int).Mul(big.NewInt(int64(*payoutFlag)), ether), big.NewInt(10))
amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil))
amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil))

tx = types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil)
} else {
tokenInfo, ok := f.bep2eInfos[msg.Symbol]
if !ok {
f.lock.Unlock()
if err = sendError(wsconn, err); err != nil {
log.Warn("Failed to send transaction creation error to client", "err", err)
return
}
log.Warn("Failed to find symbol", "symbol", msg.Symbol)
continue
}
// Submit the transaction and mark as funded if successful
if err := f.client.SendTransaction(context.Background(), signed); err != nil {
input, err := f.bep2eAbi.Pack("transfer", address, &tokenInfo.Amount)
if err != nil {
f.lock.Unlock()
if err = sendError(wsconn, err); err != nil {
log.Warn("Failed to send transaction transmission error to client", "err", err)
return
}
log.Warn("Failed to pack transfer transaction", "err", err)
continue
}
f.reqs = append(f.reqs, &request{
Avatar: avatar,
Account: address,
Time: time.Now(),
Tx: signed,
})
timeout := time.Duration(*minutesFlag*int(math.Pow(3, float64(msg.Tier)))) * time.Minute
grace := timeout / 288 // 24h timeout => 5m grace

f.timeouts[id] = time.Now().Add(timeout - grace)
f.timeouts[ips[len(ips)-2]] = time.Now().Add(timeout - grace)
fund = true
tx = types.NewTransaction(f.nonce+uint64(len(f.reqs)), tokenInfo.Contract, nil, 420000, f.price, input)
}
f.lock.Unlock()

// Send an error if too frequent funding, otherwise a success
if !fund {
if err = sendError(wsconn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(time.Until(timeout)))); err != nil { // nolint: gosimple
log.Warn("Failed to send funding error to client", "err", err)
signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainID)
if err != nil {
f.lock.Unlock()
if err = sendError(wsconn, err); err != nil {
log.Warn("Failed to send transaction creation error to client", "err", err)
return
}
continue
}
// Submit the transaction and mark as funded if successful
if err := f.client.SendTransaction(context.Background(), signed); err != nil {
f.lock.Unlock()
if err = sendError(wsconn, err); err != nil {
log.Warn("Failed to send transaction transmission error to client", "err", err)
return
}
continue
}
f.reqs = append(f.reqs, &request{
Avatar: avatar,
Account: address,
Time: time.Now(),
Tx: signed,
})
timeoutInt64 := time.Duration(*minutesFlag*int(math.Pow(3, float64(msg.Tier)))) * time.Minute
grace := timeoutInt64 / 288 // 24h timeout => 5m grace

f.timeouts[id] = time.Now().Add(timeoutInt64 - grace)
f.timeouts[ips[len(ips)-2]] = time.Now().Add(timeoutInt64 - grace)
f.lock.Unlock()
if err = sendSuccess(wsconn, fmt.Sprintf("Funding request accepted for %s into %s", username, address.Hex())); err != nil {
log.Warn("Failed to send funding success to client", "err", err)
return
Expand Down

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