1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.http.conn.routing;
29
30 import org.apache.http.annotation.Immutable;
31 import org.apache.http.util.Args;
32
33 /**
34 * Basic implementation of an {@link HttpRouteDirector HttpRouteDirector}.
35 * This implementation is stateless and therefore thread-safe.
36 *
37 * @since 4.0
38 */
39 @Immutable
40 public class BasicRouteDirector implements HttpRouteDirector {
41
42 /**
43 * Provides the next step.
44 *
45 * @param plan the planned route
46 * @param fact the currently established route, or
47 * <code>null</code> if nothing is established
48 *
49 * @return one of the constants defined in this class, indicating
50 * either the next step to perform, or success, or failure.
51 * 0 is for success, a negative value for failure.
52 */
53 public int nextStep(final RouteInfo plan, final RouteInfo fact) {
54 Args.notNull(plan, "Planned route");
55
56 int step = UNREACHABLE;
57
58 if ((fact == null) || (fact.getHopCount() < 1)) {
59 step = firstStep(plan);
60 } else if (plan.getHopCount() > 1) {
61 step = proxiedStep(plan, fact);
62 } else {
63 step = directStep(plan, fact);
64 }
65
66 return step;
67
68 } // nextStep
69
70
71 /**
72 * Determines the first step to establish a route.
73 *
74 * @param plan the planned route
75 *
76 * @return the first step
77 */
78 protected int firstStep(final RouteInfo plan) {
79
80 return (plan.getHopCount() > 1) ?
81 CONNECT_PROXY : CONNECT_TARGET;
82 }
83
84
85 /**
86 * Determines the next step to establish a direct connection.
87 *
88 * @param plan the planned route
89 * @param fact the currently established route
90 *
91 * @return one of the constants defined in this class, indicating
92 * either the next step to perform, or success, or failure
93 */
94 protected int directStep(final RouteInfo plan, final RouteInfo fact) {
95
96 if (fact.getHopCount() > 1) {
97 return UNREACHABLE;
98 }
99 if (!plan.getTargetHost().equals(fact.getTargetHost()))
100 {
101 return UNREACHABLE;
102 // If the security is too low, we could now suggest to layer
103 // a secure protocol on the direct connection. Layering on direct
104 // connections has not been supported in HttpClient 3.x, we don't
105 // consider it here until there is a real-life use case for it.
106 }
107
108 // Should we tolerate if security is better than planned?
109 // (plan.isSecure() && !fact.isSecure())
110 if (plan.isSecure() != fact.isSecure()) {
111 return UNREACHABLE;
112 }
113
114 // Local address has to match only if the plan specifies one.
115 if ((plan.getLocalAddress() != null) &&
116 !plan.getLocalAddress().equals(fact.getLocalAddress())
117 ) {
118 return UNREACHABLE;
119 }
120
121 return COMPLETE;
122 }
123
124
125 /**
126 * Determines the next step to establish a connection via proxy.
127 *
128 * @param plan the planned route
129 * @param fact the currently established route
130 *
131 * @return one of the constants defined in this class, indicating
132 * either the next step to perform, or success, or failure
133 */
134 protected int proxiedStep(final RouteInfo plan, final RouteInfo fact) {
135
136 if (fact.getHopCount() <= 1) {
137 return UNREACHABLE;
138 }
139 if (!plan.getTargetHost().equals(fact.getTargetHost())) {
140 return UNREACHABLE;
141 }
142 final int phc = plan.getHopCount();
143 final int fhc = fact.getHopCount();
144 if (phc < fhc) {
145 return UNREACHABLE;
146 }
147
148 for (int i=0; i<fhc-1; i++) {
149 if (!plan.getHopTarget(i).equals(fact.getHopTarget(i))) {
150 return UNREACHABLE;
151 }
152 }
153 // now we know that the target matches and proxies so far are the same
154 if (phc > fhc)
155 {
156 return TUNNEL_PROXY; // need to extend the proxy chain
157 }
158
159 // proxy chain and target are the same, check tunnelling and layering
160 if ((fact.isTunnelled() && !plan.isTunnelled()) ||
161 (fact.isLayered() && !plan.isLayered())) {
162 return UNREACHABLE;
163 }
164
165 if (plan.isTunnelled() && !fact.isTunnelled()) {
166 return TUNNEL_TARGET;
167 }
168 if (plan.isLayered() && !fact.isLayered()) {
169 return LAYER_PROTOCOL;
170 }
171
172 // tunnel and layering are the same, remains to check the security
173 // Should we tolerate if security is better than planned?
174 // (plan.isSecure() && !fact.isSecure())
175 if (plan.isSecure() != fact.isSecure()) {
176 return UNREACHABLE;
177 }
178
179 return COMPLETE;
180 }
181
182 }