Define keepalive protocol

The keepalive program has two procedures: PING, and PONG.
Both are used only in asynchronous messages and the sender doesn't wait
for any reply. However, the party which receives PING messages is
supposed to react by sending PONG message the other party, but no
explicit binding between PING and PONG messages is made. For backward
compatibility neither server nor client are allowed to send keepalive
messages before checking that remote party supports them.

.gitignore

@@ -65,6 +65,7 @@
 /src/locking/qemu-sanlock.conf
 /src/remote/*_client_bodies.h
 /src/remote/*_protocol.[ch]
+/src/rpc/virkeepaliveprotocol.[ch]
 /src/rpc/virnetprotocol.[ch]
 /src/util/virkeymaps.h
 /tests/*.log

src/Makefile.am

@@ -285,7 +285,8 @@ PDWTAGS = \
 PROTOCOL_STRUCTS = \
 	$(srcdir)/remote_protocol-structs \
 	$(srcdir)/qemu_protocol-structs \
-	$(srcdir)/virnetprotocol-structs
+	$(srcdir)/virnetprotocol-structs \
+	$(srcdir)/virkeepaliveprotocol-structs
 if WITH_REMOTE
 # The .o file that pdwtags parses is created as a side effect of running
 # libtool; but from make's perspective we depend on the .lo file.
@@ -293,6 +294,7 @@ $(srcdir)/%_protocol-structs: libvirt_driver_remote_la-%_protocol.lo
 	$(PDWTAGS)
 $(srcdir)/virnetprotocol-structs: libvirt_net_rpc_la-virnetprotocol.lo
 	$(PDWTAGS)
+$(srcdir)/virkeepaliveprotocol-structs: libvirt_net_rpc_la-virkeepaliveprotocol.lo
 else !WITH_REMOTE
 # These generated files must live in git, because they cannot be re-generated
 # when configured --without-remote.
@@ -1287,7 +1289,10 @@ probes.h: probes.d
 probes.o: probes.d
 	$(AM_V_GEN)$(DTRACE) -o $@ -G -s $<
 
-RPC_PROBE_FILES = $(srcdir)/rpc/virnetprotocol.x $(srcdir)/remote/remote_protocol.x $(srcdir)/remote/qemu_protocol.x
+RPC_PROBE_FILES = $(srcdir)/rpc/virnetprotocol.x \
+		  $(srcdir)/rpc/virkeepaliveprotocol.x \
+		  $(srcdir)/remote/remote_protocol.x \
+		  $(srcdir)/remote/qemu_protocol.x
 
 libvirt_functions.stp: $(RPC_PROBE_FILES) $(srcdir)/rpc/gensystemtap.pl
 	$(AM_V_GEN)perl -w $(srcdir)/rpc/gensystemtap.pl $(RPC_PROBE_FILES) > $@
@@ -1366,11 +1371,14 @@ EXTRA_DIST += \
 	rpc/gendispatch.pl \
 	rpc/genprotocol.pl \
 	rpc/gensystemtap.pl \
-	rpc/virnetprotocol.x
+	rpc/virnetprotocol.x \
+	rpc/virkeepaliveprotocol.x
 
 VIR_NET_RPC_GENERATED = \
 	$(srcdir)/rpc/virnetprotocol.h \
-	$(srcdir)/rpc/virnetprotocol.c
+	$(srcdir)/rpc/virnetprotocol.c \
+	$(srcdir)/rpc/virkeepaliveprotocol.h \
+	$(srcdir)/rpc/virkeepaliveprotocol.c
 
 BUILT_SOURCES += $(VIR_NET_RPC_GENERATED)
 
@@ -1378,7 +1386,8 @@ libvirt_net_rpc_la_SOURCES = \
 	rpc/virnetmessage.h rpc/virnetmessage.c \
 	rpc/virnetprotocol.h rpc/virnetprotocol.c \
 	rpc/virnetsocket.h rpc/virnetsocket.c \
-	rpc/virnettlscontext.h rpc/virnettlscontext.c
+	rpc/virnettlscontext.h rpc/virnettlscontext.c \
+	rpc/virkeepaliveprotocol.h rpc/virkeepaliveprotocol.c
 if HAVE_SASL
 libvirt_net_rpc_la_SOURCES += \
 	rpc/virnetsaslcontext.h rpc/virnetsaslcontext.c

src/rpc/virkeepaliveprotocol.x

+const KEEPALIVE_PROGRAM = 0x6b656570;
+const KEEPALIVE_PROTOCOL_VERSION = 1;
+
+enum keepalive_procedure {
+    KEEPALIVE_PROC_PING = 1,
+    KEEPALIVE_PROC_PONG = 2
+};