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- // Copyright 2017 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef NET_SOCKET_SOCKET_OPTIONS_H_
- #define NET_SOCKET_SOCKET_OPTIONS_H_
- #include <stdint.h>
- #include "net/base/net_export.h"
- #include "net/socket/socket_descriptor.h"
- namespace net {
- // This function enables/disables buffering in the kernel. By default, on Linux,
- // TCP sockets will wait up to 200ms for more data to complete a packet before
- // transmitting. After calling this function, the kernel will not wait. See
- // TCP_NODELAY in `man 7 tcp`.
- //
- // For Windows:
- //
- // The Nagle implementation on Windows is governed by RFC 896. The idea
- // behind Nagle is to reduce small packets on the network. When Nagle is
- // enabled, if a partial packet has been sent, the TCP stack will disallow
- // further *partial* packets until an ACK has been received from the other
- // side. Good applications should always strive to send as much data as
- // possible and avoid partial-packet sends. However, in most real world
- // applications, there are edge cases where this does not happen, and two
- // partial packets may be sent back to back. For a browser, it is NEVER
- // a benefit to delay for an RTT before the second packet is sent.
- //
- // As a practical example in Chromium today, consider the case of a small
- // POST. I have verified this:
- // Client writes 649 bytes of header (partial packet #1)
- // Client writes 50 bytes of POST data (partial packet #2)
- // In the above example, with Nagle, a RTT delay is inserted between these
- // two sends due to nagle. RTTs can easily be 100ms or more. The best
- // fix is to make sure that for POSTing data, we write as much data as
- // possible and minimize partial packets. We will fix that. But disabling
- // Nagle also ensure we don't run into this delay in other edge cases.
- // See also:
- // http://technet.microsoft.com/en-us/library/bb726981.aspx
- //
- // SetTCPNoDelay() sets the TCP_NODELAY option. Use |no_delay| to enable or
- // disable it. On error returns a net error code, on success returns OK.
- int SetTCPNoDelay(SocketDescriptor fd, bool no_delay);
- // SetReuseAddr() sets the SO_REUSEADDR socket option. Use |reuse| to enable or
- // disable it. On error returns a net error code, on success returns OK.
- int SetReuseAddr(SocketDescriptor fd, bool reuse);
- // SetSocketReceiveBufferSize() sets the SO_RCVBUF socket option. On error
- // returns a net error code, on success returns OK.
- int SetSocketReceiveBufferSize(SocketDescriptor fd, int32_t size);
- // SetSocketSendBufferSize() sets the SO_SNDBUF socket option. On error
- // returns a net error code, on success returns OK.
- int SetSocketSendBufferSize(SocketDescriptor fd, int32_t size);
- } // namespace net
- #endif // NET_SOCKET_SOCKET_OPTIONS_H_
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