Merge pull request #10447 from mheon/rootlesscni_default

Add the option of Rootless CNI networking by default

2 files changed, 223 insertions, 0 deletions

diff --git a/vendor/github.com/containers/common/pkg/defaultnet/default_network.go b/vendor/github.com/containers/common/pkg/defaultnet/default_network.go
new file mode 100644
index 000000000..9b32241d6
--- /dev/null
+++ b/vendor/github.com/containers/common/pkg/defaultnet/default_network.go
@@ -0,0 +1,222 @@
+package defaultnet
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"path/filepath"
+	"regexp"
+	"text/template"
+
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// TODO: A smarter implementation would make sure cni-podman0 was unused before
+// making the default, and adjust if necessary
+const networkTemplate = `{
+  "cniVersion": "0.4.0",
+  "name": "{{{{.Name}}}}",
+  "plugins": [
+    {
+      "type": "bridge",
+      "bridge": "cni-podman0",
+      "isGateway": true,
+      "ipMasq": true,
+      "hairpinMode": true,
+      "ipam": {
+        "type": "host-local",
+        "routes": [{ "dst": "0.0.0.0/0" }],
+        "ranges": [
+          [
+            {
+              "subnet": "{{{{.Subnet}}}}",
+              "gateway": "{{{{.Gateway}}}}"
+            }
+          ]
+        ]
+      }
+    },
+{{{{- if (eq .Machine true) }}}}
+    {
+      "type": "podman-machine",
+      "capabilities": {
+        "portMappings": true
+      }
+    },
+{{{{- end}}}}
+    {
+      "type": "portmap",
+      "capabilities": {
+        "portMappings": true
+      }
+    },
+    {
+      "type": "firewall"
+    },
+    {
+      "type": "tuning"
+    }
+  ]
+}
+`
+
+var (
+	// Borrowed from Podman, modified to remove dashes and periods.
+	nameRegex = regexp.MustCompile("^[a-zA-Z0-9][a-zA-Z0-9_]*$")
+)
+
+// Used to pass info into the template engine
+type networkInfo struct {
+	Name    string
+	Subnet  string
+	Gateway string
+	Machine bool
+}
+
+// The most trivial definition of a CNI network possible for our use here.
+// We need the name, and nothing else.
+type network struct {
+	Name string `json:"name"`
+}
+
+// Create makes the CNI default network, if necessary.
+// Accepts the name and subnet of the network to create (a standard template
+// will be used, with these values plugged in), the configuration directory
+// where CNI configs are stored (to verify if a named configuration already
+// exists), an exists directory (where a sentinel file will be stored, to ensure
+// the network is only made once), and an isMachine bool (to determine whether
+// the machine block will be added to the config).
+// Create first checks if a default network has already been created via the
+// presence of a sentinel file. If it does exist, it returns immediately without
+// error.
+// It next checks if a CNI network with the given name already exists. In that
+// case, it creates the sentinel file and returns without error.
+// If neither of these are true, the default network is created.
+func Create(name, subnet, configDir, existsDir string, isMachine bool) error {
+	// TODO: Should probably regex name to make sure it's valid.
+	if name == "" || subnet == "" || configDir == "" || existsDir == "" {
+		return errors.Errorf("must provide values for all arguments to MakeDefaultNetwork")
+	}
+	if !nameRegex.MatchString(name) {
+		return errors.Errorf("invalid default network name %s - letters, numbers, and underscores only", name)
+	}
+
+	sentinelFile := filepath.Join(existsDir, "defaultCNINetExists")
+
+	// Check if sentinel file exists, return immediately if it does.
+	if _, err := os.Stat(sentinelFile); err == nil {
+		return nil
+	}
+
+	// Create the sentinel file if it doesn't exist, so subsequent checks
+	// don't need to go further.
+	file, err := os.Create(sentinelFile)
+	if err != nil {
+		return err
+	}
+	file.Close()
+
+	// We may need to make the config dir.
+	if err := os.MkdirAll(configDir, 0755); err != nil && !os.IsExist(err) {
+		return errors.Wrapf(err, "error creating CNI configuration directory")
+	}
+
+	// Check all networks in the CNI conflist.
+	files, err := ioutil.ReadDir(configDir)
+	if err != nil {
+		return errors.Wrapf(err, "error reading CNI configuration directory")
+	}
+	if len(files) > 0 {
+		configPaths := make([]string, 0, len(files))
+		for _, path := range files {
+			if !path.IsDir() && filepath.Ext(path.Name()) == ".conflist" {
+				configPaths = append(configPaths, filepath.Join(configDir, path.Name()))
+			}
+		}
+		for _, config := range configPaths {
+			configName, err := getConfigName(config)
+			if err != nil {
+				logrus.Errorf("Error reading CNI configuration file: %v", err)
+				continue
+			}
+			if configName == name {
+				return nil
+			}
+		}
+	}
+
+	// We need to make the config.
+	// Get subnet and gateway.
+	_, ipNet, err := net.ParseCIDR(subnet)
+	if err != nil {
+		return errors.Wrapf(err, "default network subnet %s is invalid", subnet)
+	}
+
+	ones, bits := ipNet.Mask.Size()
+	if ones == bits {
+		return errors.Wrapf(err, "default network subnet %s is to small", subnet)
+	}
+	gateway := make(net.IP, len(ipNet.IP))
+	// copy the subnet ip to the gateway so we can modify it
+	copy(gateway, ipNet.IP)
+	// the default gateway should be the first ip in the subnet
+	gateway[len(gateway)-1]++
+
+	netInfo := new(networkInfo)
+	netInfo.Name = name
+	netInfo.Gateway = gateway.String()
+	netInfo.Subnet = ipNet.String()
+	netInfo.Machine = isMachine
+
+	templ, err := template.New("network_template").Delims("{{{{", "}}}}").Parse(networkTemplate)
+	if err != nil {
+		return errors.Wrapf(err, "error compiling template for default network")
+	}
+	var output bytes.Buffer
+	if err := templ.Execute(&output, netInfo); err != nil {
+		return errors.Wrapf(err, "error executing template for default network")
+	}
+
+	// Next, we need to place the config on disk.
+	// Loop through possible indexes, with a limit of 100 attempts.
+	created := false
+	for i := 87; i < 187; i++ {
+		configFile, err := os.OpenFile(filepath.Join(configDir, fmt.Sprintf("%d-%s.conflist", i, name)), os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0644)
+		if err != nil {
+			logrus.Infof("Attempt to create default CNI network config file failed: %v", err)
+			continue
+		}
+		defer configFile.Close()
+
+		created = true
+
+		// Success - file is open. Write our buffer to it.
+		if _, err := configFile.Write(output.Bytes()); err != nil {
+			return errors.Wrapf(err, "error writing default CNI config to file")
+		}
+		break
+	}
+	if !created {
+		return errors.Errorf("no available default network configuration file was found")
+	}
+
+	return nil
+}
+
+// Get the name of the configuration contained in a given conflist file. Accepts
+// the full path of a .conflist CNI configuration.
+func getConfigName(file string) (string, error) {
+	contents, err := ioutil.ReadFile(file)
+	if err != nil {
+		return "", err
+	}
+	config := new(network)
+	if err := json.Unmarshal(contents, config); err != nil {
+		return "", errors.Wrapf(err, "error decoding CNI configuration %s", filepath.Base(file))
+	}
+	return config.Name, nil
+}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index b4c2c6330..50f8e7338 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -102,6 +102,7 @@ github.com/containers/common/pkg/cgroupv2
 github.com/containers/common/pkg/chown
 github.com/containers/common/pkg/completion
 github.com/containers/common/pkg/config
+github.com/containers/common/pkg/defaultnet
 github.com/containers/common/pkg/filters
 github.com/containers/common/pkg/manifests
 github.com/containers/common/pkg/parse