This allows us to prevent users from hammering the API every few seconds
to check if any of their packages were updated. Real world users check
as often as every 5 or 10 seconds.
Signed-off-by: Florian Pritz <bluew...@xinu.at>
---
Basic idea for a rate limiting solution. Currently the cleanup of old
entries is done on each api request. That may be a bit excessive, but I
didn't find a cronjob to put it and given the table is indexed, the
query is probably fast enough. At least for a PoC this should be fine.
Tell me what you think.
conf/config.proto | 4 +++
upgrading/4.7.0.txt | 11 ++++++++
web/lib/aurjson.class.php | 71 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 86 insertions(+)
create mode 100644 upgrading/4.7.0.txt
diff --git a/conf/config.proto b/conf/config.proto
index 1750929..934d369 100644
--- a/conf/config.proto
+++ b/conf/config.proto
@@ -36,6 +36,10 @@ enable-maintenance = 1
maintenance-exceptions = 127.0.0.1
render-comment-cmd = /usr/local/bin/aurweb-rendercomment
+[ratelimit]
+request_limit = 4000
+window_length = 86400
+
[notifications]
notify-cmd = /usr/local/bin/aurweb-notify
sendmail = /usr/bin/sendmail
diff --git a/upgrading/4.7.0.txt b/upgrading/4.7.0.txt
new file mode 100644
index 0000000..1b51cd2
--- /dev/null
+++ b/upgrading/4.7.0.txt
@@ -0,0 +1,11 @@
+1. Add ApiRateLimit table:
+
+---
+CREATE TABLE `ApiRateLimit` (
+ `ip` varchar(45) CHARACTER SET ascii COLLATE ascii_bin NOT NULL,
+ `requests` int(11) NOT NULL,
+ `window_start` bigint(20) NOT NULL,
+ PRIMARY KEY (`ip`),
+ KEY `window_start_idx` (`window_start`)
+) ENGINE=InnoDB;
+---
diff --git a/web/lib/aurjson.class.php b/web/lib/aurjson.class.php
index 9eeaafd..8a6dd7b 100644
--- a/web/lib/aurjson.class.php
+++ b/web/lib/aurjson.class.php
@@ -96,6 +96,11 @@ public function handle($http_data) {
$this->dbh = DB::connect();
+ if ($this->check_ratelimit($_SERVER['REMOTE_ADDR'])) {
+ header("HTTP/1.1 429 Too Many Requests");
+ return $this->json_error('Rate limit reached');
+ }
+
$type = str_replace('-', '_', $http_data['type']);
if ($type == 'info' && $this->version >= 5) {
$type = 'multiinfo';
@@ -130,6 +135,72 @@ public function handle($http_data) {
}
}
+ /*
+ * Check if an IP needs to be rate limited.
+ *
+ * @param $ip IP of the current request
+ *
+ * @return true if IP needs to be rate limited, false otherwise.
+ */
+ private function check_ratelimit($ip) {
+ $limit = config_get("ratelimit", "request_limit");
+ $window_length = config_get("ratelimit", "window_length");
+ $this->update_ratelimit($ip);
+ $stmt = $this->dbh->prepare("
+ SELECT requests,window_start FROM ApiRateLimit
+ WHERE ip = :ip");
+ $stmt->bindParam(":ip", $ip);
+ $result = $stmt->execute();
+
+ if (!$result) {
+ return false;
+ }
+
+ $row = $stmt->fetch(PDO::FETCH_ASSOC);
+
+ if ($row['window_start'] < time() - $window_length) {
+ $stmt = $this->dbh->prepare("
+ DELETE FROM ApiRateLimit
+ WHERE ip = :ip");
+ $stmt->bindParam(":ip", $ip);
+ $stmt->execute();
+ return false;
+ }
+
+ if ($row['requests'] > $limit) {
+ return true;
+ }
+ return false;
+ }
+
+ /*
+ * Update a rate limit for an IP by increasing it's requests value by
one.
+ *
+ * @param $ip IP of the current request
+ *
+ * @return void
+ */
+ private function update_ratelimit($ip) {
+ $window_length = config_get("ratelimit", "window_length");
+ $time = time();
+ $deletion_time = $time - $window_length;
+ $stmt = $this->dbh->prepare("
+ INSERT INTO ApiRateLimit
+ (ip, requests, window_start)
+ VALUES (:ip, 0, :window_start)
+ ON DUPLICATE KEY UPDATE requests=requests+1");
+ $stmt->bindParam(":ip", $ip);
+ $stmt->bindParam(":window_start", $time);
+ $stmt->execute();
+
+ // TODO: this should move into some cronjob
+ $stmt = $this->dbh->prepare("
+ DELETE FROM ApiRateLimit
+ WHERE window_start < :time");
+ $stmt->bindParam(":time", $deletion_time);
+ $stmt->execute();
+ }
+
/*
* Returns a JSON formatted error string.
*
--
2.15.1
