adb: use TCP keepalive.
Currently adb only realizes a TCP transport has gone away when it tries
to send a packet, which caused problems in particular for `adb reboot`
since no packets are sent, leading to the client hanging until Ctrl+C.
This CL turns on TCP keepalive packets to send 1 packet every second,
allowing up to 10 failures before disconnecting. Using built-in TCP
functionality turns out to be much cleaner in this case than trying to
implement our own keepalive packets at the application layer, and
should be more lightweight since it's all done in the TCP stack.
Bug: http://b/23093474
Change-Id: Ifb41cbb85b9752a9f394e1eed3c6ac4da47a4e4d
diff --git a/services.cpp b/services.cpp
index 2eef1c2..d5e963b 100644
--- a/services.cpp
+++ b/services.cpp
@@ -421,6 +421,11 @@
close_on_exec(fd);
disable_tcp_nagle(fd);
+ // Send a TCP keepalive ping to the device every second so we can detect disconnects.
+ if (!set_tcp_keepalive(fd, 1)) {
+ D("warning: failed to configure TCP keepalives (%s)", strerror(errno));
+ }
+
int ret = register_socket_transport(fd, serial.c_str(), port, 0);
if (ret < 0) {
adb_close(fd);