1 files changed, 86 insertions, 0 deletions
diff --git a/pkg/tcpip/stack/icmp_rate_limit.go b/pkg/tcpip/stack/icmp_rate_limit.go
new file mode 100644
index 000000000..f8156be47
--- /dev/null
+++ b/pkg/tcpip/stack/icmp_rate_limit.go
@@ -0,0 +1,86 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stack
+
+import (
+	"sync"
+
+	"golang.org/x/time/rate"
+)
+
+const (
+	// icmpLimit is the default maximum number of ICMP messages permitted by this
+	// rate limiter.
+	icmpLimit = 1000
+
+	// icmpBurst is the default number of ICMP messages that can be sent in a single
+	// burst.
+	icmpBurst = 50
+)
+
+// ICMPRateLimiter is a global rate limiter that controls the generation of
+// ICMP messages generated by the stack.
+type ICMPRateLimiter struct {
+	mu sync.RWMutex
+	l  *rate.Limiter
+}
+
+// NewICMPRateLimiter returns a global rate limiter for controlling the rate
+// at which ICMP messages are generated by the stack.
+func NewICMPRateLimiter() *ICMPRateLimiter {
+	return &ICMPRateLimiter{l: rate.NewLimiter(icmpLimit, icmpBurst)}
+}
+
+// Allow returns true if we are allowed to send at least 1 message at the
+// moment.
+func (i *ICMPRateLimiter) Allow() bool {
+	i.mu.RLock()
+	allow := i.l.Allow()
+	i.mu.RUnlock()
+	return allow
+}
+
+// Limit returns the maximum number of ICMP messages that can be sent in one
+// second.
+func (i *ICMPRateLimiter) Limit() rate.Limit {
+	i.mu.RLock()
+	defer i.mu.RUnlock()
+	return i.l.Limit()
+}
+
+// SetLimit sets the maximum number of ICMP messages that can be sent in one
+// second.
+func (i *ICMPRateLimiter) SetLimit(newLimit rate.Limit) {
+	i.mu.RLock()
+	defer i.mu.RUnlock()
+	i.l.SetLimit(newLimit)
+}
+
+// Burst returns how many ICMP messages can be sent at any single instant.
+func (i *ICMPRateLimiter) Burst() int {
+	i.mu.RLock()
+	defer i.mu.RUnlock()
+	return i.l.Burst()
+}
+
+// SetBurst sets the maximum number of ICMP messages allowed at any single
+// instant.
+//
+// NOTE: Changing Burst causes the underlying rate limiter to be recreated.
+func (i *ICMPRateLimiter) SetBurst(burst int) {
+	i.mu.Lock()
+	i.l = rate.NewLimiter(i.l.Limit(), burst)
+	i.mu.Unlock()
+}