1 files changed, 122 insertions, 0 deletions
diff --git a/lib/policy/policy.go b/lib/policy/policy.go
new file mode 100644
index 0000000..51b23ff
--- /dev/null
+++ b/lib/policy/policy.go
@@ -0,0 +1,122 @@
+package policy
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"regexp"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/yl2chen/cidranger"
+
+	"github.com/TecharoHQ/anubis/lib/policy/config"
+)
+
+var (
+	PolicyApplications = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "anubis_policy_results",
+		Help: "The results of each policy rule",
+	}, []string{"rule", "action"})
+)
+
+type ParsedConfig struct {
+	orig config.Config
+
+	Bots              []Bot
+	DNSBL             bool
+	DefaultDifficulty int
+}
+
+func NewParsedConfig(orig config.Config) *ParsedConfig {
+	return &ParsedConfig{
+		orig: orig,
+	}
+}
+
+func ParseConfig(fin io.Reader, fname string, defaultDifficulty int) (*ParsedConfig, error) {
+	var c config.Config
+	if err := json.NewDecoder(fin).Decode(&c); err != nil {
+		return nil, fmt.Errorf("can't parse policy config JSON %s: %w", fname, err)
+	}
+
+	if err := c.Valid(); err != nil {
+		return nil, err
+	}
+
+	var err error
+
+	result := NewParsedConfig(c)
+	result.DefaultDifficulty = defaultDifficulty
+
+	for _, b := range c.Bots {
+		if berr := b.Valid(); berr != nil {
+			err = errors.Join(err, berr)
+			continue
+		}
+
+		var botParseErr error
+		parsedBot := Bot{
+			Name:   b.Name,
+			Action: b.Action,
+		}
+
+		if b.RemoteAddr != nil && len(b.RemoteAddr) > 0 {
+			parsedBot.Ranger = cidranger.NewPCTrieRanger()
+
+			for _, cidr := range b.RemoteAddr {
+				_, rng, err := net.ParseCIDR(cidr)
+				if err != nil {
+					return nil, fmt.Errorf("[unexpected] range %s not parsing: %w", cidr, err)
+				}
+
+				parsedBot.Ranger.Insert(cidranger.NewBasicRangerEntry(*rng))
+			}
+		}
+
+		if b.UserAgentRegex != nil {
+			userAgent, err := regexp.Compile(*b.UserAgentRegex)
+			if err != nil {
+				botParseErr = errors.Join(botParseErr, fmt.Errorf("while compiling user agent regexp: %w", err))
+				continue
+			} else {
+				parsedBot.UserAgent = userAgent
+			}
+		}
+
+		if b.PathRegex != nil {
+			path, err := regexp.Compile(*b.PathRegex)
+			if err != nil {
+				botParseErr = errors.Join(botParseErr, fmt.Errorf("while compiling path regexp: %w", err))
+				continue
+			} else {
+				parsedBot.Path = path
+			}
+		}
+
+		if b.Challenge == nil {
+			parsedBot.Challenge = &config.ChallengeRules{
+				Difficulty: defaultDifficulty,
+				ReportAs:   defaultDifficulty,
+				Algorithm:  config.AlgorithmFast,
+			}
+		} else {
+			parsedBot.Challenge = b.Challenge
+			if parsedBot.Challenge.Algorithm == config.AlgorithmUnknown {
+				parsedBot.Challenge.Algorithm = config.AlgorithmFast
+			}
+		}
+
+		result.Bots = append(result.Bots, parsedBot)
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("errors validating policy config JSON %s: %w", fname, err)
+	}
+
+	result.DNSBL = c.DNSBL
+
+	return result, nil
+}