From: Ansis Atteka
Currently ovs-vswitchd process can communicate with an OpenFlow
controller only through tcp, unix and ssl sockets.
This patch would allow ovs-vswitchd process to communicate
with an OpenFlow controller by directly calling into its
code that provides interface similar to a socket (ie
implements read() and write() functions).
There are few benefits of using shared library as OpenFlow
controller:
1. Better performance by
a) avoiding copying OpenFlow messages to socket buffers; AND
b) reducing context switches.
The preliminary tests that I did improved performance by ~30% for
an OpenFlow controller that handles PACKET_INs and resubmits packets
with PACKET_OUTs.
2. Better parallelization in future by distributing the load
over ovs-vswitchd handler threads (currently only one thread calls into
the shared library code).
3. Eliminate undeterministic thread blocking that may be caused when
socket buffers are full.
4. In some cases better security (e.g. by allowing to confine ovs-vswitchd
process to a stricter Access Control policy). Although, In some cases
security may get worse (e.g. because controller would run in the same
virtual memory space as ovs-vswitchd process).
While the code is enough to demonstrate PoC, I have left some TODOs.
Because of that I am sending this code as RFC to hear more feedback
from community on subjects as
1. what should be the API that shared libraries should export.
2. if I am possibly missing something critical that makes this approach
not feasible (e.g. race conditions, something that ovs does behind
scenes (like vlog module initialization for plugin) and would require
overhaul in other components, impossible to integrate code with event
loop, inpractical cleanups that would make it impossible
to unload plugins)
In this patch I am proposing an API that requires library to export
socket functions that mimic socket read() and write() functions. In some
cases this allows to easy retrofit existing OpenFlow controllers as
shared library plugins. To test out one can set test controller with
ovs-vsctl add-br brX
ovs-vsctl set-controller brX dl:/ovs/tests/.libs/libtest-dl.so
sudo ovs-ofctl add-flow brX "actions=controller"
And observe that packet-ins get to OpenFlow controller plugin:
2019-03-25T04:10:35.615Z|01230|libtestdl|INFO|received 255 byte message from
Open vSwitch
2019-03-25T04:10:35.615Z|01231|libtestdl|INFO|Received OFPTYPE_PACKET_IN
2019-03-25T04:10:36.616Z|01232|libtestdl|INFO|received 255 byte message from
Open vSwitch
2019-03-25T04:10:36.616Z|01233|libtestdl|INFO|Received OFPTYPE_PACKET_IN
2019-03-25T04:10:38.143Z|01234|libtestdl|INFO|received 8 byte message from Open
vSwitch
Another approach would be for shared libraries to export init() and
finit() functions that would self register and self-unregisters certain class
implementations.
Signed-off-by: Ansis Atteka
---
Makefile.am | 2 +-
lib/automake.mk | 3 +
lib/stream-dl.c | 161 +++
lib/stream-dl.h | 28 +
lib/stream-dlopen.c | 79 +++
lib/stream-provider.h | 3 +
lib/stream.c | 1 +
lib/vconn-provider.h | 1 +
lib/vconn-stream.c| 2 +
lib/vconn.c | 1 +
tests/automake.mk | 6 ++
tests/test-dl.c | 169 ++
12 files changed, 455 insertions(+), 1 deletion(-)
create mode 100644 lib/stream-dl.c
create mode 100644 lib/stream-dl.h
create mode 100644 lib/stream-dlopen.c
create mode 100644 tests/test-dl.c
diff --git a/Makefile.am b/Makefile.am
index ff1f94b48..7cb0a6b55 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -338,7 +338,7 @@ thread-safety-check:
if test -e .git && (git --version) >/dev/null 2>&1 && \
grep -n -f build-aux/thread-safety-blacklist \
`git ls-files | grep '\.[ch]$$' \
- | $(EGREP) -v '^datapath|^lib/sflow|^third-party'` /dev/null \
+ | $(EGREP) -v '^datapath|^lib/sflow|^lib/stream-dl|^third-party'`
/dev/null \
| $(EGREP) -v ':[ ]*/?\*'; \
then \
echo "See above for list of calls to functions that are"; \
diff --git a/lib/automake.mk b/lib/automake.mk
index cc5dccf39..1e9a6eefa 100644
--- a/lib/automake.mk
+++ b/lib/automake.mk
@@ -269,6 +269,8 @@ lib_libopenvswitch_la_SOURCES = \
lib/sset.h \
lib/stp.c \
lib/stp.h \
+lib/stream-dl.c \
+lib/stream-dl.h \
lib/stream-fd.c \
lib/stream-fd.h \
lib/stream-provider.h \
@@ -346,6 +348,7 @@ lib_libopenvswitch_la_SOURCES += \
lib/signals.c \
lib/signals.h \
lib/socket-util-unix.c \
+lib/stream-dlopen.c \
lib/stream-unix.c
endif
diff --git a/lib/stream-dl.c b/lib/stream-dl.c
new file mode 100644
index 0..1ff7dfd8e
--- /dev/null
+++ b/lib/stream-dl.c
@@ -0,0 +1,161 @@
+/*
+ * Copyr
