Initial commit

1 files changed, 99 insertions, 0 deletions

diff --git a/pkg/config/service.go b/pkg/config/service.go
new file mode 100644
index 0000000..3c9a27e
--- /dev/null
+++ b/pkg/config/service.go
@@ -0,0 +1,99 @@
+package config
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"regexp"
+
+	validate "github.com/go-playground/validator/v10"
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Hostname string `yaml:"host" validate:"required"`
+	TLS      struct {
+		Enabled bool   `yaml:"enabled"`
+		Cert    string `yaml:"cert"`
+		Key     string `yaml:"key"`
+	} `yaml:"tls"`
+	WireGuard struct {
+		Network       string `yaml:"network" validate:"cidr,required"`
+		Port          string `yaml:"port" validate:"required"`
+		InterfaceName string `yaml:"interfaceName" validate:"required"`
+	} `yaml:"wireGuard"`
+	ExpireAfter int `yaml:"expireAfter"`
+}
+
+type Service interface {
+	InitialiseConfig(paths ...string) error
+	Config() *Config
+}
+
+type service struct {
+	config    *Config
+	validator *validate.Validate
+}
+
+const InterfaceRegex = "^[a-zA-Z0-9_=+.-]{1,15}$"
+
+func NewService() Service {
+	return &service{
+		validator: validate.New(validate.WithRequiredStructEnabled()),
+	}
+}
+
+func (s *service) InitialiseConfig(paths ...string) error {
+	for _, p := range paths {
+		if _, err := os.Stat(p); err != nil {
+			continue
+		}
+		c := &Config{}
+		err := readConfig(p, c)
+		if err != nil {
+			return err
+		}
+		s.config = c
+		break
+	}
+	return nil
+}
+
+func (s *service) Config() *Config {
+	return s.config
+}
+
+func readConfig(configPath string, dst *Config) error {
+	config, err := os.ReadFile(configPath)
+	if err != nil {
+		return err
+	}
+
+	if err := yaml.Unmarshal(config, dst); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *service) validateConfig(c *Config) error {
+	if err := s.validator.Struct(c); err != nil {
+		return err
+	}
+
+	match, _ := regexp.MatchString(InterfaceRegex, c.WireGuard.InterfaceName)
+	if !match {
+		return fmt.Errorf("invalid interface name: %s", c.WireGuard.InterfaceName)
+	}
+
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return fmt.Errorf("could not list network interfaces: %w", err)
+	}
+	for _, i := range ifaces {
+		if i.Name == c.WireGuard.InterfaceName {
+			return fmt.Errorf("an interface already exists with the name '%s'", i.Name)
+		}
+	}
+
+	return nil
+}