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