mirror of
https://github.com/gravitational/teleport.git
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rosstimothy
3d5557d947
Introduces `limiter.Listener` to provide a consistent and reusable mechanism for limiting incoming connections per client. The new listener is used by `sshutils/server.go` instead of manually applying limits in `HandleConnection`. This is particularly important now that the Proxy SSH port multiplexes both SSH and gRPC. Each listener is now wrapped in a `limiter.Listener` that uses the same `limiter.ConnectionsListener` to ensure that the connection limits for the Proxy are enforced for all traffic on the port.
125 lines
3.0 KiB
Go
125 lines
3.0 KiB
Go
/*
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Copyright 2015 Gravitational, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package limiter
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import (
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"net/http"
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"sync"
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"github.com/gravitational/oxy/connlimit"
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"github.com/gravitational/oxy/utils"
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"github.com/gravitational/trace"
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log "github.com/sirupsen/logrus"
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)
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// ConnectionsLimiter is a network connection limiter and tracker
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type ConnectionsLimiter struct {
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*connlimit.ConnLimiter
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maxConnections int64
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sync.Mutex
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connections map[string]int64
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}
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// NewConnectionsLimiter returns new connection limiter, in case if connection
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// limits are not set, they won't be tracked
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func NewConnectionsLimiter(config Config) (*ConnectionsLimiter, error) {
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limiter := ConnectionsLimiter{
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maxConnections: config.MaxConnections,
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connections: make(map[string]int64),
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}
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ipExtractor, err := utils.NewExtractor("client.ip")
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if err != nil {
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return nil, trace.Wrap(err)
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}
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limiter.ConnLimiter, err = connlimit.New(nil, ipExtractor, config.MaxConnections)
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if err != nil {
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return nil, trace.Wrap(err)
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}
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return &limiter, nil
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}
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// WrapHandle adds connection limiter to the handle
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func (l *ConnectionsLimiter) WrapHandle(h http.Handler) {
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l.ConnLimiter.Wrap(h)
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}
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// AcquireConnection acquires connection and bumps counter
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func (l *ConnectionsLimiter) AcquireConnection(token string) error {
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if l.maxConnections == 0 {
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return nil
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}
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l.Lock()
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defer l.Unlock()
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numberOfConnections, exists := l.connections[token]
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if !exists {
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l.connections[token] = 1
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return nil
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}
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if numberOfConnections >= l.maxConnections {
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return trace.LimitExceeded("too many connections from %v: %v, max is %v", token, numberOfConnections, l.maxConnections)
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}
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l.connections[token] = numberOfConnections + 1
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return nil
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}
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// ReleaseConnection decrements the counter
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func (l *ConnectionsLimiter) ReleaseConnection(token string) {
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if l.maxConnections == 0 {
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return
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}
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l.Lock()
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defer l.Unlock()
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numberOfConnections, exists := l.connections[token]
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if !exists {
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log.Errorf("Trying to set negative number of connections")
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return
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}
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if numberOfConnections <= 1 {
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delete(l.connections, token)
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} else {
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l.connections[token] = numberOfConnections - 1
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}
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}
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// GetNumConnection returns the current number of connections for a token
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func (l *ConnectionsLimiter) GetNumConnection(token string) (int64, error) {
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if l.maxConnections == 0 {
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return 0, nil
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}
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l.Lock()
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defer l.Unlock()
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numberOfConnections, exists := l.connections[token]
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if !exists {
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return -1, trace.BadParameter("unable to get connections of a nonexistent token: %q", token)
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}
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return numberOfConnections, nil
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}
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