Merge branch 'dev' into agent-master

Add ability to claim multiple tokens.

rules/falco_rules.yaml

@@ -433,7 +433,7 @@
     and shell_procs
     and proc.pname exists
     and not proc.pname in (shell_binaries, docker_binaries, k8s_binaries, lxd_binaries, aide_wrapper_binaries, nids_binaries,
-                           monitoring_binaries, gitlab_binaries, initdb, pg_ctl, awk, apache2, falco, cron, erl_child_setup)
+                           monitoring_binaries, gitlab_binaries, initdb, pg_ctl, awk, falco, cron, erl_child_setup)
     and not trusted_containers
   output: "Shell spawned in a container other than entrypoint (user=%user.name %container.info shell=%proc.name parent=%proc.pname cmdline=%proc.cmdline)"
   priority: WARNING

userspace/engine/token_bucket.cpp

@@ -31,20 +31,30 @@ token_bucket::~token_bucket()
 {
 }
 
-void token_bucket::init(uint32_t rate, uint32_t max_tokens)
+void token_bucket::init(double rate, double max_tokens, uint64_t now)
 {
 	m_rate = rate;
 	m_max_tokens = max_tokens;
 	m_tokens = max_tokens;
-	m_last_seen = sinsp_utils::get_current_time_ns();
+
+	if(now == 0)
+	{
+		now = sinsp_utils::get_current_time_ns();
+	}
+
+	m_last_seen = now;
 }
 
 bool token_bucket::claim()
 {
-	// Determine the number of tokens gained. Delta between
-	// last_seen and now, divided by the rate.
 	uint64_t now = sinsp_utils::get_current_time_ns();
-	uint64_t tokens_gained = (now - m_last_seen) / (m_rate * 1000000000);
+
+	return claim(1, now);
+}
+
+bool token_bucket::claim(double tokens, uint64_t now)
+{
+	double tokens_gained = m_rate * ((now - m_last_seen) / (1000000000.0));
 	m_last_seen = now;
 
 	m_tokens += tokens_gained;
@@ -58,14 +68,24 @@ bool token_bucket::claim()
 	}
 
 	//
-	// If tokens is < 1, can't claim.
+	// If m_tokens is < tokens, can't claim.
 	//
-	if(m_tokens < 1)
+	if(m_tokens < tokens)
 	{
 		return false;
 	}
 
-	m_tokens--;
+	m_tokens -= tokens;
 
 	return true;
 }
+
+double token_bucket::get_tokens()
+{
+	return m_tokens;
+}
+
+uint64_t token_bucket::get_last_seen()
+{
+	return m_last_seen;
+}

userspace/engine/token_bucket.h

@@ -31,30 +31,42 @@ public:
 	//
 	// Initialize the token bucket and start accumulating tokens
 	//
-	void init(uint32_t rate, uint32_t max_tokens);
+	void init(double rate, double max_tokens, uint64_t now = 0);
 
 	//
-	// Returns true if a token can be claimed. Also updates
-	// internal metrics.
+	// Try to claim tokens tokens from the token bucket, using a
+	// timestamp of now. Returns true if the tokens could be
+	// claimed. Also updates internal metrics.
 	//
+	bool claim(double tokens, uint64_t now);
+
+	// Simpler version of claim that claims a single token and
+	// uses the current time for now
 	bool claim();
+
+	// Return the current number of tokens available
+	double get_tokens();
+
+	// Return the last time someone tried to claim a token.
+	uint64_t get_last_seen();
+
 private:
 
 	//
 	// The number of tokens generated per second.
 	//
-	uint64_t m_rate;
+	double m_rate;
 
 	//
 	// The maximum number of tokens that can be banked for future
 	// claim()s.
 	//
-	uint64_t m_max_tokens;
+	double m_max_tokens;
 
 	//
 	// The current number of tokens
 	//
-	uint64_t m_tokens;
+	double m_tokens;
 
 	//
 	// The last time claim() was called (or the object was created).