rootless: use RootlessKit port forwarder

RootlessKit port forwarder has a lot of advantages over the slirp4netns port forwarder:

* Very high throughput.
  Benchmark result on Travis: socat: 5.2 Gbps, slirp4netns: 8.3 Gbps, RootlessKit: 27.3 Gbps
  (https://travis-ci.org/rootless-containers/rootlesskit/builds/597056377)

* Connections from the host are treated as 127.0.0.1 rather than 10.0.2.2 in the namespace.
  No UDP issue (#4586)

* No tcp_rmem issue (#4537)

* Probably works with IPv6. Even if not, it is trivial to support IPv6.  (#4311)

* Easily extensible for future support of SCTP

* Easily extensible for future support of `lxc-user-nic` SUID network

RootlessKit port forwarder has been already adopted as the default port forwarder by Rootless Docker/Moby,
and no issue has been reported AFAIK.

As the port forwarder is imported as a Go package, no `rootlesskit` binary is required for Podman.

Fix #4586
May-fix #4559
Fix #4537
May-fix #4311

See https://github.com/rootless-containers/rootlesskit/blob/v0.7.0/pkg/port/builtin/builtin.go

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

1 files changed, 3 insertions, 0 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 2693190b5..edf72f4ee 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -135,6 +135,9 @@ type Container struct {
 	rootlessSlirpSyncR *os.File
 	rootlessSlirpSyncW *os.File
 
+	rootlessPortSyncR *os.File
+	rootlessPortSyncW *os.File
+
 	// A restored container should have the same IP address as before
 	// being checkpointed. If requestedIP is set it will be used instead
 	// of config.StaticIP.