netavark network interface

Implement a new network interface for netavark.
For now only bridge networking is supported.
The interface can create/list/inspect/remove networks. For setup and
teardown netavark will be invoked.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

1 files changed, 116 insertions, 0 deletions

diff --git a/libpod/network/netavark/exec.go b/libpod/network/netavark/exec.go
new file mode 100644
index 000000000..700df9a69
--- /dev/null
+++ b/libpod/network/netavark/exec.go
@@ -0,0 +1,116 @@
+package netavark
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"os/exec"
+	"strconv"
+
+	"github.com/sirupsen/logrus"
+)
+
+type netavarkError struct {
+	exitCode int
+	// Set the json key to "error" so we can directly unmarshal into this struct
+	Msg string `json:"error"`
+	err error
+}
+
+func (e *netavarkError) Error() string {
+	ec := ""
+	// only add the exit code the the error message if we have at least info log level
+	// the normal user does not need to care about the number
+	if e.exitCode > 0 && logrus.IsLevelEnabled(logrus.InfoLevel) {
+		ec = " (exit code " + strconv.Itoa(e.exitCode) + ")"
+	}
+	msg := "netavark" + ec
+	if len(msg) > 0 {
+		msg += ": " + e.Msg
+	}
+	if e.err != nil {
+		msg += ": " + e.err.Error()
+	}
+	return msg
+}
+
+func (e *netavarkError) Unwrap() error {
+	return e.err
+}
+
+func newNetavarkError(msg string, err error) error {
+	return &netavarkError{
+		Msg: msg,
+		err: err,
+	}
+}
+
+// execNetavark will execute netavark with the following arguments
+// It takes the path to the binary, the list of args and an interface which is
+// marshaled to json and send via stdin to netavark. The result interface is
+// used to marshal the netavark output into it. This can be nil.
+// All errors return by this function should be of the type netavarkError
+// to provide a helpful error message.
+func execNetavark(binary string, args []string, stdin, result interface{}) error {
+	stdinR, stdinW, err := os.Pipe()
+	if err != nil {
+		return newNetavarkError("failed to create stdin pipe", err)
+	}
+	defer stdinR.Close()
+
+	stdoutR, stdoutW, err := os.Pipe()
+	if err != nil {
+		return newNetavarkError("failed to create stdout pipe", err)
+	}
+	defer stdoutR.Close()
+	defer stdoutW.Close()
+
+	cmd := exec.Command(binary, args...)
+	// connect the pipes to stdin and stdout
+	cmd.Stdin = stdinR
+	cmd.Stdout = stdoutW
+	// connect stderr to the podman stderr for logging
+	cmd.Stderr = os.Stderr
+	// set the netavark log level to the same as the podman
+	cmd.Env = append(os.Environ(), "RUST_LOG="+logrus.GetLevel().String())
+	// if we run with debug log level lets also set RUST_BACKTRACE=1 so we can get the full stack trace in case of panics
+	if logrus.IsLevelEnabled(logrus.DebugLevel) {
+		cmd.Env = append(cmd.Env, "RUST_BACKTRACE=1")
+	}
+
+	err = cmd.Start()
+	if err != nil {
+		return newNetavarkError("failed to start process", err)
+	}
+	err = json.NewEncoder(stdinW).Encode(stdin)
+	stdinW.Close()
+	if err != nil {
+		return newNetavarkError("failed to encode stdin data", err)
+	}
+
+	dec := json.NewDecoder(stdoutR)
+
+	err = cmd.Wait()
+	stdoutW.Close()
+	if err != nil {
+		exitError := &exec.ExitError{}
+		if errors.As(err, &exitError) {
+			ne := &netavarkError{}
+			// lets disallow unknown fields to make sure we do not get some unexpected stuff
+			dec.DisallowUnknownFields()
+			// this will unmarshal the error message into the error struct
+			ne.err = dec.Decode(ne)
+			ne.exitCode = exitError.ExitCode()
+			return ne
+		}
+		return newNetavarkError("unexpected failure during execution", err)
+	}
+
+	if result != nil {
+		err = dec.Decode(result)
+		if err != nil {
+			return newNetavarkError("failed to decode result", err)
+		}
+	}
+	return nil
+}