/
error.go
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/
error.go
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// Copyright 2015 The Mellium Contributors.
// Use of this source code is governed by the BSD 2-clause
// license that can be found in the LICENSE file.
package stream
import (
"encoding/xml"
"io"
"net"
"mellium.im/xmlstream"
"mellium.im/xmpp/internal/ns"
)
// A list of stream errors defined in RFC 6120 §4.9.3
var (
// BadFormat is used when the entity has sent XML that cannot be processed.
// This error can be used instead of the more specific XML-related errors,
// such as <bad-namespace-prefix/>, <invalid-xml/>, <not-well-formed/>,
// <restricted-xml/>, and <unsupported-encoding/>. However, the more specific
// errors are RECOMMENDED.
BadFormat = Error{Err: "bad-format"}
// BadNamespacePrefix is sent when an entity has sent a namespace prefix that
// is unsupported, or has sent no namespace prefix, on an element that needs
// such a prefix.
BadNamespacePrefix = Error{Err: "bad-namespace-prefix"}
// Conflict is sent when the server either (1) is closing the existing stream
// for this entity because a new stream has been initiated that conflicts with
// the existing stream, or (2) is refusing a new stream for this entity
// because allowing the new stream would conflict with an existing stream
// (e.g., because the server allows only a certain number of connections from
// the same IP address or allows only one server-to-server stream for a given
// domain pair as a way of helping to ensure in-order processing.
Conflict = Error{Err: "conflict"}
// ConnectionTimeout results when one party is closing the stream because it
// has reason to believe that the other party has permanently lost the ability
// to communicate over the stream.
ConnectionTimeout = Error{Err: "connection-timeout"}
// HostGone is sent when the value of the 'to' attribute provided in the
// initial stream header corresponds to an FQDN that is no longer serviced by
// the receiving entity.
HostGone = Error{Err: "host-gone"}
// HostUnknown is sent when the value of the 'to' attribute provided in the
// initial stream header does not correspond to an FQDN that is serviced by
// the receiving entity.
HostUnknown = Error{Err: "host-unknown"}
// ImproperAddressing is used when a stanza sent between two servers lacks a
// 'to' or 'from' attribute, the 'from' or 'to' attribute has no value, or the
// value violates the rules for XMPP addresses.
ImproperAddressing = Error{Err: "improper-addressing"}
// InternalServerError is sent when the server has experienced a
// misconfiguration or other internal error that prevents it from servicing
// the stream.
InternalServerError = Error{Err: "internal-server-error"}
// InvalidFrom is sent when data provided in a 'from' attribute does not match
// an authorized JID or validated domain as negotiated (1) between two servers
// using SASL or Server Dialback, or (2) between a client and a server via
// SASL authentication and resource binding.
InvalidFrom = Error{Err: "invalid-from"}
// InvalidNamespace may be sent when the stream namespace name is something
// other than "http://etherx.jabber.org/streams" or the content namespace
// declared as the default namespace is not supported (e.g., something other
// than "jabber:client" or "jabber:server").
InvalidNamespace = Error{Err: "invalid-namespace"}
// InvalidXML may be sent when the entity has sent invalid XML over the stream
// to a server that performs validation.
InvalidXML = Error{Err: "invalid-xml"}
// NotAuthorized may be sent when the entity has attempted to send XML stanzas
// or other outbound data before the stream has been authenticated, or
// otherwise is not authorized to perform an action related to stream
// negotiation; the receiving entity MUST NOT process the offending data
// before sending the stream error.
NotAuthorized = Error{Err: "not-authorized"}
// NotWellFormed may be sent when the initiating entity has sent XML that
// violates the well-formedness rules of XML or XML namespaces.
NotWellFormed = Error{Err: "not-well-formed"}
// PolicyViolation may be sent when an entity has violated some local service
// policy (e.g., a stanza exceeds a configured size limit).
PolicyViolation = Error{Err: "policy-violation"}
// RemoteConnectionFailed may be sent when the server is unable to properly
// connect to a remote entity that is needed for authentication or
// authorization
RemoteConnectionFailed = Error{Err: "remote-connection-failed"}
// server is closing the stream because it has new (typically
// security-critical) features to offer, because the keys or certificates used
// to establish a secure context for the stream have expired or have been
// revoked during the life of the stream, because the TLS sequence number has
// wrapped, etc. Encryption and authentication need to be negotiated again for
// the new stream (e.g., TLS session resumption cannot be used).
Reset = Error{Err: "reset"}
// ResourceConstraing may be sent when the server lacks the system resources
// necessary to service the stream.
ResourceConstraint = Error{Err: "resource-constraint"}
// RestrictedXML may be sent when the entity has attempted to send restricted
// XML features such as a comment, processing instruction, DTD subset, or XML
// entity reference.
RestrictedXML = Error{Err: "restricted-xml"}
// SystemShutdown may be sent when server is being shut down and all active
// streams are being closed.
SystemShutdown = Error{Err: "system-shutdown"}
// UndefinedCondition may be sent when the error condition is not one of those
// defined by the other conditions in this list; this error condition should
// be used in conjunction with an application-specific condition.
UndefinedCondition = Error{Err: "undefined-condition"}
// UnsupportedEncoding may be sent when initiating entity has encoded the
// stream in an encoding that is not UTF-8.
UnsupportedEncoding = Error{Err: "unsupported-encoding"}
// UnsupportedFeature may be sent when receiving entity has advertised a
// mandatory-to-negotiate stream feature that the initiating entity does not
// support.
UnsupportedFeature = Error{Err: "unsupported-feature"}
// UnsupportedStanzaType may be sent when the initiating entity has sent a
// first-level child of the stream that is not supported by the server, either
// because the receiving entity does not understand the namespace or because
// the receiving entity does not understand the element name for the
// applicable namespace (which might be the content namespace declared as the
// default namespace).
UnsupportedStanzaType = Error{Err: "unsupported-stanza-type"}
// UnsupportedVersion may be sent when the 'version' attribute provided by the
// initiating entity in the stream header specifies a version of XMPP that is
// not supported by the server.
UnsupportedVersion = Error{Err: "unsupported-version"}
)
// SeeOtherHostError returns a new see-other-host error with the given network
// address as the host.
func SeeOtherHostError(addr net.Addr) Error {
cdata := addr.String()
// If the address looks like a raw IPv6 literal, wrap it in []
if ip := net.ParseIP(cdata); ip != nil && ip.To4() == nil && ip.To16() != nil {
cdata = "[" + cdata + "]"
}
return Error{
Err: "see-other-host",
// This needs to return the CharData every time in case we use this error
// multiple times, so use a custom ReaderFunc and not the stateful
// xmlstream.Token.
innerXML: xmlstream.ReaderFunc(func() (xml.Token, error) {
return xml.CharData(cdata), io.EOF
}),
}
}
// Error represents an unrecoverable stream-level error that may include
// character data or arbitrary inner XML.
type Error struct {
Err string
Text []struct {
Lang string
Value string
}
innerXML xml.TokenReader
payload xml.TokenReader
}
// Is will be used by errors.Is when comparing errors.
// For more information see the errors package.
func (s Error) Is(err error) bool {
se, ok := err.(Error)
if !ok {
return false
}
if se.Err == "" {
return true
}
return se.Err == s.Err
}
// Error satisfies the builtin error interface and returns the name of the
// StreamError. For instance, given the error:
//
// <stream:error>
// <restricted-xml xmlns="urn:ietf:params:xml:ns:xmpp-streams"/>
// </stream:error>
//
// Error() would return "restricted-xml".
func (s Error) Error() string {
return s.Err
}
// UnmarshalXML satisfies the xml package's Unmarshaler interface and allows
// StreamError's to be correctly unmarshaled from XML.
func (s *Error) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
for {
tok, err := d.Token()
if err == io.EOF {
err = nil
if tok == nil {
return nil
}
}
if err != nil {
return err
}
var start xml.StartElement
switch tt := tok.(type) {
case xml.StartElement:
start = tt
case xml.EndElement:
// This is the end element, everything else has been unmarshaled or skipped.
return nil
default:
continue
}
switch {
case start.Name.Local == "text" && start.Name.Space == NSError:
var lang string
for _, attr := range start.Attr {
if attr.Name.Local == "lang" && attr.Name.Space == ns.XML {
lang = attr.Value
break
}
}
t := struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-streams text"`
Text string `xml:",chardata"`
}{}
err = d.DecodeElement(&t, &start)
if err != nil {
return err
}
s.Text = append(s.Text, struct {
Lang string
Value string
}{
Lang: lang,
Value: t.Text,
})
case start.Name.Space == NSError:
s.Err = start.Name.Local
}
if err = d.Skip(); err != nil {
return err
}
}
}
// MarshalXML satisfies the xml package's Marshaler interface and allows
// StreamError's to be correctly marshaled back into XML.
func (s Error) MarshalXML(e *xml.Encoder, _ xml.StartElement) error {
_, err := s.WriteXML(e)
return err
}
// WriteXML satisfies the xmlstream.WriterTo interface.
// It is like MarshalXML except it writes tokens to w.
func (s Error) WriteXML(w xmlstream.TokenWriter) (n int, err error) {
return xmlstream.Copy(w, s.TokenReader())
}
// TokenReader returns a new xml.TokenReader that returns an encoding of
// the error.
func (s Error) TokenReader() xml.TokenReader {
inner := xmlstream.Wrap(s.innerXML, xml.StartElement{Name: xml.Name{Local: s.Err, Space: NSError}})
if s.payload != nil {
inner = xmlstream.MultiReader(
inner,
s.payload,
)
}
for _, txt := range s.Text {
start := xml.StartElement{Name: xml.Name{Space: NSError, Local: "text"}}
if txt.Lang != "" {
start.Attr = append(start.Attr, xml.Attr{
Name: xml.Name{Space: ns.XML, Local: "lang"},
Value: txt.Lang,
})
}
inner = xmlstream.MultiReader(
inner,
xmlstream.Wrap(
xmlstream.Token(xml.CharData(txt.Value)),
start,
),
)
}
return xmlstream.Wrap(
inner,
xml.StartElement{
Name: xml.Name{Local: "error", Space: NS},
},
)
}
// ApplicationError returns a copy of the Error with the provided application
// level error included alongside the error condition.
// Multiple, chained, calls to ApplicationError will replace the payload each
// time and only the final call will have any effect.
//
// Because the TokenReader will be consumed during marshalling errors created
// with this method may only be marshaled once.
func (s Error) ApplicationError(r xml.TokenReader) Error {
s.payload = r
return s
}
// InnerXML returns a copy of the Error that marshals the provided reader after
// the error condition start token.
// Multiple, chained, calls to InnerXML will replace the inner XML each time
// and only the final call will have any effect.
//
// Because the TokenReader will be consumed during marshalling errors created
// with this method may only be marshaled once.
func (s Error) InnerXML(r xml.TokenReader) Error {
s.innerXML = r
return s
}