filter

Documentation

Overview

Package filter contains the filter interface and its implementations along with types that combine them based on the settings in profile and filtering group.

Index

• Constants
• type DefaultStorage
  • func NewDefaultStorage(c *DefaultStorageConfig) (s *DefaultStorage, err error)
  • func (s *DefaultStorage) FilterFromContext(ctx context.Context, ri *agd.RequestInfo) (f Interface)
  • func (s *DefaultStorage) HasListID(id agd.FilterListID) (ok bool)
  • func (s *DefaultStorage) Refresh(ctx context.Context) (err error)
• type DefaultStorageConfig
• type HashMatcher
• type Interface
• type Result
• type ResultAllowed
• type ResultBlocked
• type ResultModified
• type Storage

Constants

const (
	GeneralTXTSuffix       = ".sb.dns.adguard.com"
	AdultBlockingTXTSuffix = ".pc.dns.adguard.com"
)

Default safe-browsing host suffixes.

Types

type DefaultStorage

type DefaultStorage struct {
	// contains filtered or unexported fields
}

DefaultStorage is the default storage for filters, including the filters based on rule lists, custom filters of profiles, safe browsing, and safe search ones.

func NewDefaultStorage

func NewDefaultStorage(c *DefaultStorageConfig) (s *DefaultStorage, err error)

NewDefaultStorage returns a new filter storage. c must not be nil.

func (*DefaultStorage) FilterFromContext

func (s *DefaultStorage) FilterFromContext(ctx context.Context, ri *agd.RequestInfo) (f Interface)

FilterFromContext implements the Storage interface for *DefaultStorage.

func (*DefaultStorage) HasListID

func (s *DefaultStorage) HasListID(id agd.FilterListID) (ok bool)

HasListID implements the Storage interface for *DefaultStorage.

func (*DefaultStorage) Refresh

func (s *DefaultStorage) Refresh(ctx context.Context) (err error)

Refresh implements the agdservice.Refresher interface for *DefaultStorage.

type DefaultStorageConfig

type DefaultStorageConfig struct {
	// FilterIndexURL is the URL of the filtering rule index document.
	FilterIndexURL *url.URL

	// BlockedServiceIndexURL is the URL of the blocked service index document.
	BlockedServiceIndexURL *url.URL

	// GeneralSafeSearchRulesURL is the URL to refresh general safe search rules
	// list.
	GeneralSafeSearchRulesURL *url.URL

	// YoutubeSafeSearchRulesURL is the URL to refresh YouTube safe search rules
	// list.
	YoutubeSafeSearchRulesURL *url.URL

	// SafeBrowsing is the configuration for the default safe browsing filter.
	// It must not be nil.
	SafeBrowsing *hashprefix.Filter

	// AdultBlocking is the configuration for the adult content blocking safe
	// browsing filter.  It must not be nil.
	AdultBlocking *hashprefix.Filter

	// NewRegDomains is the configuration for the newly registered domains safe
	// browsing filter.  It must not be nil.
	NewRegDomains *hashprefix.Filter

	// Now is a function that returns current time.
	Now func() (now time.Time)

	// ErrColl is used to collect non-critical and rare errors.
	ErrColl errcoll.Interface

	// Resolver is used to resolve hosts in safe search.
	Resolver agdnet.Resolver

	// Cloner is used to clone messages taken from filtering-result caches.
	Cloner *dnsmsg.Cloner

	// CacheDir is the path to the directory where the cached filter files are
	// put.  The directory must exist.
	CacheDir string

	// CustomFilterCacheSize is the number of cached custom filters for
	// profiles.
	CustomFilterCacheSize int

	// SafeSearchCacheSize is the size of the LRU cache of results of the safe
	// search filters: the general one and the YouTube one.
	SafeSearchCacheSize int

	// SafeSearchCacheTTL is the time-to-live value used for the cache of
	// results of the safe search filters: the general one and the YouTube one.
	SafeSearchCacheTTL time.Duration

	// RuleListCacheSize defines the size of the LRU cache of rule-list
	// filtering results.
	RuleListCacheSize int

	// RefreshIvl is the refresh interval for this storage.  It defines how
	// often the filter rule lists are updated from the index.
	//
	// TODO(a.garipov): This value is used both for refreshes and for filter
	// staleness, which can cause issues.  Consider splitting the two.
	RefreshIvl time.Duration

	// UseRuleListCache, if true, enables rule list cache.
	UseRuleListCache bool

	// MaxRuleListSize is the maximum size in bytes of the downloadable
	// rule-list content.
	MaxRuleListSize uint64
}

DefaultStorageConfig contains configuration for a filter storage based on rule lists.

type HashMatcher

type HashMatcher interface {
	MatchByPrefix(ctx context.Context, host string) (hashes []string, matched bool, err error)
}

HashMatcher is the interface for a safe-browsing and adult-blocking hash matcher, which is used to respond to a TXT query based on the domain name.

type Interface

type Interface = internal.Interface

Interface is the DNS request and response filter interface.

type Result

type Result = internal.Result

Result is a sum type of all possible filtering actions. See the following types as implementations:

• *ResultAllowed
• *ResultBlocked
• *ResultModified

type ResultAllowed

type ResultAllowed = internal.ResultAllowed

ResultAllowed means that this request or response was allowed by an allowlist rule within the given filter list.

type ResultBlocked

type ResultBlocked = internal.ResultBlocked

ResultBlocked means that this request or response was blocked by a blocklist rule within the given filter list.

type ResultModified

type ResultModified = internal.ResultModified

ResultModified means that this request or response was rewritten or modified by a rewrite rule within the given filter list.

type Storage

type Storage interface {
	// FilterFromContext returns a filter combining rules and types of filtering
	// for all entities from the context.  ri must not be nil.
	FilterFromContext(ctx context.Context, ri *agd.RequestInfo) (f Interface)

	// HasListID returns true if id is within the rule lists that are currently
	// in the storage.
	HasListID(id agd.FilterListID) (ok bool)
}

Storage is a storage for filters.