Merge pull request #13 from pperiyasamy/ovs_mcp

Add MCP Tools for OVS layer

Author: tssurya

cmd/ovnk-mcp-server/main.go

@@ -12,6 +12,7 @@ import (
 
 	mcp "github.com/modelcontextprotocol/go-sdk/mcp"
 	kubernetesmcp "github.com/ovn-kubernetes/ovn-kubernetes-mcp/pkg/kubernetes/mcp"
+	ovsmcp "github.com/ovn-kubernetes/ovn-kubernetes-mcp/pkg/ovs/mcp"
 	sosreportmcp "github.com/ovn-kubernetes/ovn-kubernetes-mcp/pkg/sosreport/mcp"
 )
 
@@ -37,6 +38,9 @@ func main() {
 		}
 		log.Println("Adding Kubernetes tools to OVN-K MCP server")
 		k8sMcpServer.AddTools(ovnkMcpServer)
+		ovsServer := ovsmcp.NewMCPServer(k8sMcpServer)
+		log.Println("Adding OVS tools to OVN-K MCP server")
+		ovsServer.AddTools(ovnkMcpServer)
 	}
 	if serverCfg.Mode == "offline" {
 		sosreportServer := sosreportmcp.NewMCPServer()

pkg/ovs/mcp/commands.go

@@ -0,0 +1,126 @@
+package mcp
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	k8stypes "github.com/ovn-kubernetes/ovn-kubernetes-mcp/pkg/kubernetes/types"
+)
+
+const defaultMaxLines = 100
+
+func (s *MCPServer) runCommand(ctx context.Context, req *mcp.CallToolRequest, namespacedName k8stypes.NamespacedNameParams,
+	commands []string) ([]string, error) {
+	_, result, err := s.k8sMcpServer.ExecPod(ctx, req, k8stypes.ExecPodParams{NamespacedNameParams: namespacedName, Command: commands})
+	if err != nil {
+		return nil, err
+	}
+	if result.Stderr != "" {
+		return nil, fmt.Errorf("error occurred while running command %v on pod %s/%s: %s", commands, namespacedName.Namespace,
+			namespacedName.Name, result.Stderr)
+	}
+	output := []string{} // Initialize with empty slice to ensure valid JSON when there's no output
+	for _, line := range strings.Split(result.Stdout, "\n") {
+		line = strings.TrimSpace(line)
+		if line != "" {
+			output = append(output, line)
+		}
+	}
+	return output, nil
+}
+
+// filterLines filters lines using a regex pattern.
+func filterLines(lines []string, pattern string) ([]string, error) {
+	if pattern == "" {
+		return lines, nil
+	}
+
+	filterPattern, err := regexp.Compile(pattern)
+	if err != nil {
+		return nil, fmt.Errorf("invalid filter pattern %s: %w", pattern, err)
+	}
+
+	filtered := []string{} // Initialize with empty slice to ensure valid JSON when there's no output
+	for _, line := range lines {
+		if filterPattern.MatchString(line) {
+			filtered = append(filtered, line)
+		}
+	}
+	return filtered, nil
+}
+
+// limitLines limits the number of lines returned.
+func limitLines(lines []string, maxLines int) []string {
+	if maxLines <= 0 {
+		maxLines = defaultMaxLines
+	}
+	if len(lines) > maxLines {
+		return lines[:maxLines]
+	}
+	return lines
+}
+
+// validateBridgeName validates that a bridge name is safe and non-empty.
+// Bridge names should only contain alphanumeric characters, hyphens, and underscores.
+func validateBridgeName(bridge string) error {
+	if bridge == "" {
+		return fmt.Errorf("bridge name cannot be empty")
+	}
+
+	// OVS bridge names typically follow naming conventions: alphanumeric, hyphens, underscores
+	validBridgeName := regexp.MustCompile(`^[a-zA-Z0-9_-]+$`)
+	if !validBridgeName.MatchString(bridge) {
+		return fmt.Errorf("invalid bridge name %q: must contain only alphanumeric characters, hyphens, and underscores", bridge)
+	}
+
+	return nil
+}
+
+// validateFlowSpec validates that a flow specification is safe and non-empty.
+func validateFlowSpec(flow string) error {
+	if flow == "" {
+		return fmt.Errorf("flow specification cannot be empty")
+	}
+
+	// Check for potentially dangerous characters that shouldn't appear in flow specs
+	// Flow specs should contain: alphanumeric, commas, equals, colons, periods, slashes, parentheses, brackets
+	// We explicitly block: semicolons, pipes, backticks, dollar signs, and other shell metacharacters
+	dangerousChars := regexp.MustCompile(`[;&|$` + "`" + `<>\\]`)
+	if dangerousChars.MatchString(flow) {
+		return fmt.Errorf("invalid flow specification: contains potentially dangerous characters")
+	}
+
+	return nil
+}
+
+// validateConntrackParams validates that conntrack additional parameters are safe.
+// Valid parameters for dpctl/dump-conntrack include: zone=N, mark=0xN, labels=0xN, -m, -s, etc.
+func validateConntrackParams(params []string) error {
+	for _, param := range params {
+		if param == "" {
+			return fmt.Errorf("conntrack parameter cannot be empty")
+		}
+
+		// Check for potentially dangerous characters
+		// Valid conntrack params should contain: alphanumeric, equals, hyphens, underscores, periods, colons, commas, forward slashes
+		// We explicitly block: semicolons, pipes, backticks, dollar signs, ampersands, and other shell metacharacters
+		dangerousChars := regexp.MustCompile(`[;&|$` + "`" + `<>\\()]`)
+		if dangerousChars.MatchString(param) {
+			return fmt.Errorf("invalid conntrack parameter %q: contains potentially dangerous characters", param)
+		}
+
+		// Additional validation for common parameter patterns
+		// Valid patterns include:
+		// - Single-char flags: -m, -s (single hyphen followed by single letter)
+		// - Key=value pairs: zone=5, mark=0x1, src=10.0.0.1 (key must contain only alphanumeric, underscore, hyphen)
+		validParam := regexp.MustCompile(`^(-[a-zA-Z]|[a-zA-Z0-9_-]+=[a-zA-Z0-9x.:,/_-]+)$`)
+		if !validParam.MatchString(param) {
+			return fmt.Errorf("invalid conntrack parameter format %q: must be a flag (e.g., '-m') or key=value pair (e.g., 'zone=5')", param)
+		}
+	}
+
+	return nil
+}