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package main
import (
"context"
"crypto/sha256"
"errors"
"fmt"
"github.com/flier/gohs/hyperscan"
log "github.com/sirupsen/logrus"
"sync"
"time"
)
type RegexFlags struct {
Caseless bool `json:"caseless"` // Set case-insensitive matching.
DotAll bool `json:"dot_all"` // Matching a `.` will not exclude newlines.
MultiLine bool `json:"multi_line"` // Set multi-line anchoring.
SingleMatch bool `json:"single_match"` // Set single-match only mode.
Utf8Mode bool `json:"utf_8_mode"` // Enable UTF-8 mode for this expression.
UnicodeProperty bool `json:"unicode_property"` // Enable Unicode property support for this expression
}
type Pattern struct {
Regex string `json:"regex"`
Flags RegexFlags `json:"flags"`
MinOccurrences int `json:"min_occurrences"`
MaxOccurrences int `json:"max_occurrences"`
internalID int
compiledPattern *hyperscan.Pattern
}
type Filter struct {
ServicePort int
ClientAddress string
ClientPort int
MinDuration int
MaxDuration int
MinPackets int
MaxPackets int
MinSize int
MaxSize int
}
type Rule struct {
ID RowID `json:"-" bson:"_id,omitempty"`
Name string `json:"name" binding:"required,min=3" bson:"name"`
Color string `json:"color" binding:"required,hexcolor" bson:"color"`
Notes string `json:"notes" bson:"notes,omitempty"`
Enabled bool `json:"enabled" bson:"enabled"`
Patterns []Pattern `json:"patterns" binding:"required,min=1" bson:"patterns"`
Filter Filter `json:"filter" bson:"filter,omitempty"`
Version int64 `json:"version" bson:"version"`
}
type RulesDatabase struct {
database hyperscan.StreamDatabase
databaseSize int
version RowID
}
type RulesManager interface {
LoadRules() error
AddRule(context context.Context, rule Rule) (string, error)
FillWithMatchedRules(connection *Connection, clientMatches map[uint][]PatternSlice, serverMatches map[uint][]PatternSlice)
DatabaseUpdateChannel() chan RulesDatabase
}
type rulesManagerImpl struct {
storage Storage
rules map[string]Rule
rulesByName map[string]Rule
ruleIndex int
patterns map[string]Pattern
mPatterns sync.Mutex
databaseUpdated chan RulesDatabase
}
func NewRulesManager(storage Storage) RulesManager {
return &rulesManagerImpl{
storage: storage,
rules: make(map[string]Rule),
patterns: make(map[string]Pattern),
mPatterns: sync.Mutex{},
}
}
func (rm rulesManagerImpl) LoadRules() error {
var rules []Rule
if err := rm.storage.Find(Rules).Sort("_id", true).All(&rules); err != nil {
return err
}
for _, rule := range rules {
if err := rm.validateAndAddRuleLocal(&rule); err != nil {
log.WithError(err).WithField("rule", rule).Warn("failed to import rule")
}
}
rm.ruleIndex = len(rules)
return rm.generateDatabase(rules[len(rules)-1].ID)
}
func (rm rulesManagerImpl) AddRule(context context.Context, rule Rule) (string, error) {
rm.mPatterns.Lock()
rule.ID = rm.storage.NewCustomRowID(uint64(rm.ruleIndex), time.Now())
rule.Enabled = true
if err := rm.validateAndAddRuleLocal(&rule); err != nil {
rm.mPatterns.Unlock()
return "", err
}
if err := rm.generateDatabase(rule.ID); err != nil {
rm.mPatterns.Unlock()
log.WithError(err).WithField("rule", rule).Panic("failed to generate database")
}
rm.mPatterns.Unlock()
if _, err := rm.storage.Insert(Rules).Context(context).One(rule); err != nil {
log.WithError(err).WithField("rule", rule).Panic("failed to insert rule on database")
}
return rule.ID.Hex(), nil
}
func (rm rulesManagerImpl) validateAndAddRuleLocal(rule *Rule) error {
if _, alreadyPresent := rm.rulesByName[rule.Name]; alreadyPresent {
return errors.New("rule name must be unique")
}
newPatterns := make(map[string]Pattern)
for i, pattern := range rule.Patterns {
hash := pattern.Hash()
if existingPattern, isPresent := rm.patterns[hash]; isPresent {
rule.Patterns[i] = existingPattern
continue
}
err := pattern.BuildPattern()
if err != nil {
return err
}
pattern.internalID = len(rm.patterns) + len(newPatterns)
newPatterns[hash] = pattern
}
for key, value := range newPatterns {
rm.patterns[key] = value
}
rm.rules[rule.ID.Hex()] = *rule
rm.rulesByName[rule.Name] = *rule
return nil
}
func (rm rulesManagerImpl) generateDatabase(version RowID) error {
patterns := make([]*hyperscan.Pattern, len(rm.patterns))
var i int
for _, pattern := range rm.patterns {
patterns[i] = pattern.compiledPattern
i++
}
database, err := hyperscan.NewStreamDatabase(patterns...)
if err != nil {
return err
}
rm.databaseUpdated <- RulesDatabase{
database: database,
databaseSize: len(patterns),
version: version,
}
return nil
}
func (rm rulesManagerImpl) FillWithMatchedRules(connection *Connection, clientMatches map[uint][]PatternSlice,
serverMatches map[uint][]PatternSlice) {
}
func (rm rulesManagerImpl) DatabaseUpdateChannel() chan RulesDatabase {
return rm.databaseUpdated
}
func (p Pattern) BuildPattern() error {
if p.compiledPattern != nil {
return nil
}
if p.MinOccurrences <= 0 {
return errors.New("min_occurrences can't be lower than zero")
}
if p.MaxOccurrences != -1 && p.MinOccurrences < p.MinOccurrences {
return errors.New("max_occurrences can't be lower than min_occurrences")
}
hp, err := hyperscan.ParsePattern(fmt.Sprintf("/%s/", p.Regex))
if err != nil {
return err
}
if p.Flags.Caseless {
hp.Flags |= hyperscan.Caseless
}
if p.Flags.DotAll {
hp.Flags |= hyperscan.DotAll
}
if p.Flags.MultiLine {
hp.Flags |= hyperscan.MultiLine
}
if p.Flags.SingleMatch {
hp.Flags |= hyperscan.SingleMatch
}
if p.Flags.Utf8Mode {
hp.Flags |= hyperscan.Utf8Mode
}
if p.Flags.UnicodeProperty {
hp.Flags |= hyperscan.UnicodeProperty
}
if !hp.IsValid() {
return errors.New("can't validate the pattern")
}
return nil
}
func (p Pattern) Hash() string {
hash := sha256.New()
hash.Write([]byte(fmt.Sprintf("%s|%v|%v|%v", p.Regex, p.Flags, p.MinOccurrences, p.MaxOccurrences)))
return fmt.Sprintf("%x", hash.Sum(nil))
}
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