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1 // Copyright 2012 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef NET_BASE_LOAD_TIMING_INFO_H_
6 #define NET_BASE_LOAD_TIMING_INFO_H_
7 
8 #include <stdint.h>
9 
10 #include "base/time/time.h"
11 #include "net/base/net_export.h"
12 
13 namespace net {
14 
15 // Structure containing timing information for a request.
16 // It addresses the needs of
17 // http://groups.google.com/group/http-archive-specification/web/har-1-1-spec,
18 // http://dev.w3.org/2006/webapi/WebTiming/, and
19 // http://www.w3.org/TR/resource-timing/.
20 //
21 // All events that do not apply to a request have null times.  For non-HTTP
22 // requests, all times other than the request_start times are null.
23 //
24 // Requests with connection errors generally only have request start times as
25 // well, since they never received an established socket.
26 //
27 // The general order for events is:
28 // request_start
29 // service_worker_router_evaluation_start
30 // service_worker_cache_lookup_start
31 // service_worker_start_time
32 // proxy_start
33 // proxy_end
34 // domain_lookup_start
35 // domain_lookup_end
36 // connect_start
37 // ssl_start
38 // ssl_end
39 // connect_end
40 // send_start
41 // send_end
42 // service_worker_ready_time
43 // service_worker_fetch_start
44 // service_worker_respond_with_settled
45 // first_early_hints_time
46 // receive_headers_start
47 // receive_non_informational_headers_start
48 // receive_headers_end
49 //
50 // Times represent when a request starts/stops blocking on an event(*), not the
51 // time the events actually occurred. In particular, in the case of preconnects
52 // and socket reuse, no time may be spent blocking on establishing a connection.
53 // In the case of SPDY, PAC scripts are only run once for each shared session,
54 // so no time may be spent blocking on them.
55 //
56 // (*) Note 1: push_start and push_end are the exception to this, as they
57 // represent the operation which is asynchronous to normal request flow and
58 // hence are provided as absolute values and not converted to "blocking" time.
59 //
60 // (*) Note 2: Internally to the network stack, times are those of actual event
61 // occurrence. URLRequest converts them to time which the network stack was
62 // blocked on each state, as per resource timing specs.
63 //
64 // DNS and SSL times are both times for the host, not the proxy, so DNS times
65 // when using proxies are null, and only requests to HTTPS hosts (Not proxies)
66 // have SSL times.
67 struct NET_EXPORT LoadTimingInfo {
68   // Contains the LoadTimingInfo events related to establishing a connection.
69   // These are all set by ConnectJobs.
70   struct NET_EXPORT_PRIVATE ConnectTiming {
71     ConnectTiming();
72     ~ConnectTiming();
73 
74     // The time spent looking up the host's DNS address.  Null for requests that
75     // used proxies to look up the DNS address.  Also null for SOCKS4 proxies,
76     // since the DNS address is only looked up after the connection is
77     // established, which results in unexpected event ordering.
78     // TODO(mmenke):  The SOCKS4 event ordering could be refactored to allow
79     //                these times to be non-null.
80     // Corresponds to |domainLookupStart| and |domainLookupEnd| in
81     // ResourceTiming (http://www.w3.org/TR/resource-timing/) for Web-surfacing
82     // requests.
83     base::TimeTicks domain_lookup_start;
84     base::TimeTicks domain_lookup_end;
85 
86     // The time spent establishing the connection. Connect time includes proxy
87     // connect times (though not proxy_resolve or DNS lookup times), time spent
88     // waiting in certain queues, TCP, and SSL time.
89     // TODO(mmenke):  For proxies, this includes time spent blocking on higher
90     //                level socket pools.  Fix this.
91     // TODO(mmenke):  Retried connections to the same server should apparently
92     //                be included in this time.  Consider supporting that.
93     //                Since the network stack has multiple notions of a "retry",
94     //                handled at different levels, this may not be worth
95     //                worrying about - backup jobs, reused socket failure,
96     //                multiple round authentication.
97     // Corresponds to |connectStart| and |connectEnd| in ResourceTiming
98     // (http://www.w3.org/TR/resource-timing/) for Web-surfacing requests.
99     base::TimeTicks connect_start;
100     base::TimeTicks connect_end;
101 
102     // The time when the SSL handshake started / completed. For non-HTTPS
103     // requests these are null.  These times are only for the SSL connection to
104     // the final destination server, not an SSL/SPDY proxy.
105     // |ssl_start| corresponds to |secureConnectionStart| in ResourceTiming
106     // (http://www.w3.org/TR/resource-timing/) for Web-surfacing requests.
107     base::TimeTicks ssl_start;
108     base::TimeTicks ssl_end;
109   };
110 
111   LoadTimingInfo();
112   LoadTimingInfo(const LoadTimingInfo& other);
113   ~LoadTimingInfo();
114 
115   // True if the socket was reused.  When true, DNS, connect, and SSL times
116   // will all be null.  When false, those times may be null, too, for non-HTTP
117   // requests, or when they don't apply to a request.
118   //
119   // For requests that are sent again after an AUTH challenge, this will be true
120   // if the original socket is reused, and false if a new socket is used.
121   // Responding to a proxy AUTH challenge is never considered to be reusing a
122   // socket, since a connection to the host wasn't established when the
123   // challenge was received.
124   bool socket_reused = false;
125 
126   // Unique socket ID, can be used to identify requests served by the same
127   // socket.  For connections tunnelled over SPDY proxies, this is the ID of
128   // the virtual connection (The SpdyProxyClientSocket), not the ID of the
129   // actual socket.  HTTP requests handled by the SPDY proxy itself all use the
130   // actual socket's ID.
131   //
132   // 0 when there is no socket associated with the request, or it's not an HTTP
133   // request.
134   uint32_t socket_log_id;
135 
136   // Start time as a base::Time, so times can be coverted into actual times.
137   // Other times are recorded as TimeTicks so they are not affected by clock
138   // changes.
139   base::Time request_start_time;
140 
141   // Corresponds to |fetchStart| in ResourceTiming
142   // (http://www.w3.org/TR/resource-timing/) for Web-surfacing requests.
143   // Note that this field is not used in ResourceTiming as |requestStart|, which
144   // has the same name but exposes a different field.
145   base::TimeTicks request_start;
146 
147   // The time immediately before ServiceWorker static routing API starts
148   // matching a request with the registered router rules.
149   base::TimeTicks service_worker_router_evaluation_start;
150 
151   // The time immediately before ServiceWorker static routing API starts
152   // looking up the cache storage when "cache" is specified as its source.
153   base::TimeTicks service_worker_cache_lookup_start;
154 
155   // The time immediately before starting ServiceWorker. If the response is not
156   // provided by the ServiceWorker, kept empty.
157   // Corresponds to |workerStart| in
158   // ResourceTiming (http://www.w3.org/TR/resource-timing/) for Web-surfacing
159   base::TimeTicks service_worker_start_time;
160 
161   // The time immediately before dispatching fetch event in ServiceWorker.
162   // If the response is not provided by the ServiceWorker, kept empty.
163   // This value will be used for |fetchStart| (or |redirectStart|) in
164   // ResourceTiming (http://www.w3.org/TR/resource-timing/) for Web-surfacing
165   // if this is greater than |request_start|.
166   base::TimeTicks service_worker_ready_time;
167 
168   // The time when serviceworker fetch event was popped off the event queue
169   // and fetch event handler started running.
170   // If the response is not provided by the ServiceWorker, kept empty.
171   base::TimeTicks service_worker_fetch_start;
172 
173   // The time when serviceworker's fetch event's respondWith promise was
174   // settled. If the response is not provided by the ServiceWorker, kept empty.
175   base::TimeTicks service_worker_respond_with_settled;
176 
177   // The time spent determining which proxy to use.  Null when there is no PAC.
178   base::TimeTicks proxy_resolve_start;
179   base::TimeTicks proxy_resolve_end;
180 
181   ConnectTiming connect_timing;
182 
183   // The time that sending HTTP request started / ended.
184   // |send_start| corresponds to |requestStart| in ResourceTiming
185   // (http://www.w3.org/TR/resource-timing/) for Web-surfacing requests.
186   base::TimeTicks send_start;
187   base::TimeTicks send_end;
188 
189   // The time at which the first / last byte of the HTTP headers were received.
190   //
191   // |receive_headers_start| corresponds to |responseStart| in ResourceTiming
192   // (http://www.w3.org/TR/resource-timing/) for Web-surfacing requests. This
193   // can be the time at which the first byte of the HTTP headers for
194   // informational responses (1xx) as per the ResourceTiming spec (see note at
195   // https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-responsestart).
196   base::TimeTicks receive_headers_start;
197   base::TimeTicks receive_headers_end;
198 
199   // The time at which the first byte of the HTTP headers for the
200   // non-informational response (non-1xx). See also comments on
201   // |receive_headers_start|.
202   base::TimeTicks receive_non_informational_headers_start;
203 
204   // The time that the first 103 Early Hints response is received.
205   base::TimeTicks first_early_hints_time;
206 
207   // In case the resource was proactively pushed by the server, these are
208   // the times that push started and ended. Note that push_end will be null
209   // if the request is still being transmitted, i.e. the underlying h2 stream
210   // is not closed by the server.
211   base::TimeTicks push_start;
212   base::TimeTicks push_end;
213 };
214 
215 }  // namespace net
216 
217 #endif  // NET_BASE_LOAD_TIMING_INFO_H_
218