internal

Documentation

Overview

Package internal contains common constants, types, and utilities shared by other subpackages of package filter/.

Index

• Constants
• type Interface
• type Refreshable
  • func NewRefreshable(c *RefreshableConfig) (f *Refreshable)
  • func (f *Refreshable) Refresh(ctx context.Context, acceptStale bool) (text string, err error)
• type RefreshableConfig
• type RequestFilter
• type Result
• type ResultAllowed
  • func (a *ResultAllowed) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)
• type ResultBlocked
  • func (b *ResultBlocked) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)
• type ResultModified
  • func (m *ResultModified) Clone(c *dnsmsg.Cloner) (clone *ResultModified)
  • func (m *ResultModified) CloneForReq(c *dnsmsg.Cloner, req *dns.Msg) (clone *ResultModified)
  • func (m *ResultModified) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)

Constants

const DefaultFilterRefreshTimeout = 3 * time.Minute

DefaultFilterRefreshTimeout is the default timeout to use when fetching filter lists data.

const DefaultResolveTimeout = 1 * time.Second

DefaultResolveTimeout is the default timeout for resolving hosts for safe-search and safe-browsing filters.

TODO(ameshkov): Consider making configurable.

Types

type Interface

type Interface interface {
	// FilterRequest filters the DNS request for the provided client.  All
	// parameters must be non-nil.  req must have exactly one question.  If a is
	// nil, the request doesn't match any of the rules.
	FilterRequest(ctx context.Context, req *dns.Msg, ri *agd.RequestInfo) (r Result, err error)

	// FilterResponse filters the DNS response for the provided client.  All
	// parameters must be non-nil.  If a is nil, the response doesn't match any
	// of the rules.
	FilterResponse(ctx context.Context, resp *dns.Msg, ri *agd.RequestInfo) (r Result, err error)
}

Interface is the DNS request and response filter interface.

type Refreshable

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

Refreshable contains entities common to filters that can refresh themselves from a file and a URL.

func NewRefreshable

func NewRefreshable(c *RefreshableConfig) (f *Refreshable)

NewRefreshable returns a new refreshable filter. c must not be nil.

func (*Refreshable) Refresh

func (f *Refreshable) Refresh(
	ctx context.Context,
	acceptStale bool,
) (text string, err error)

Refresh reloads the filter data. If acceptStale is true, refresh doesn't try to load the filter data from its URL when there is already a file in the cache directory, regardless of its staleness.

TODO(a.garipov): Consider making refresh return a reader instead of a string.

type RefreshableConfig

type RefreshableConfig struct {
	// URL is the URL used to refresh the filter.
	URL *url.URL

	// ID is the filter list ID for this filter.
	ID agd.FilterListID

	// CachePath is the path to the file containing the cached filter rules.
	CachePath string

	// Staleness is the time after which a file is considered stale.
	Staleness time.Duration

	// Timeout is the timeout for the HTTP client used by this refreshable
	// filter.
	Timeout time.Duration

	// MaxSize is the maximum size in bytes of the downloadable filter content.
	MaxSize uint64
}

RefreshableConfig is the configuration structure for a refreshable filter.

type RequestFilter

type RequestFilter interface {
	FilterRequest(ctx context.Context, req *dns.Msg, ri *agd.RequestInfo) (r Result, err error)
	ID() (id agd.FilterListID)
}

RequestFilter can filter a request based on the request info.

type Result

type Result interface {
	// MatchedRule returns data about the matched rule and its rule list.
	MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)
	// contains filtered or unexported methods
}

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

• *ResultAllowed
• *ResultBlocked
• *ResultModified

type ResultAllowed

type ResultAllowed struct {
	List agd.FilterListID
	Rule agd.FilterRuleText
}

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

func (*ResultAllowed) MatchedRule

func (a *ResultAllowed) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)

MatchedRule implements the Result interface for *ResultAllowed.

type ResultBlocked

type ResultBlocked struct {
	List agd.FilterListID
	Rule agd.FilterRuleText
}

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

func (*ResultBlocked) MatchedRule

func (b *ResultBlocked) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)

MatchedRule implements the Result interface for *ResultBlocked.

type ResultModified

type ResultModified struct {
	// Msg is the new, rewritten or modified request or response.
	Msg *dns.Msg

	// List is the ID of the filter list.
	List agd.FilterListID

	// Rule is the filtering rule that triggered the rewrite.
	Rule agd.FilterRuleText
}

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

func (*ResultModified) Clone

func (m *ResultModified) Clone(c *dnsmsg.Cloner) (clone *ResultModified)

Clone returns a deep clone of m.

func (*ResultModified) CloneForReq

func (m *ResultModified) CloneForReq(c *dnsmsg.Cloner, req *dns.Msg) (clone *ResultModified)

CloneForReq returns a deep clone of m with Msg set as a reply to req, if any.

func (*ResultModified) MatchedRule

func (m *ResultModified) MatchedRule() (id agd.FilterListID, text agd.FilterRuleText)

MatchedRule implements the Result interface for *ResultModified.