internal ResolutionResult(int nestingLevel, DnsClient.Request request, DnsClient.Response response, NameServerCollection authorities)
{
this.NestingLevel = nestingLevel;
this.Request = request;
this.Response = response;
_Authorities = authorities;
}
internal ResolutionResult(int nestingLevel, DnsClient.Request request, DnsClient.Response response, NameServerCollection authorities)
{
this.NestingLevel = nestingLevel;
this.Request = request;
this.Response = response;
_Authorities = authorities;
}
public virtual void Reset()
{
CurrentResult = null;
IsCompleted = false;
_IterationCount = 0;
StoredAuthorities = null;
}
//protected virtual void OnResolutionCompleted(DnsClient.DNS.QTYPE question, DnsClient.Response response)
//{
// IEnumerable<DnsClient.DNS.RR> requested = response.AnswerRecords.OfQuestion(question);
// if (requested.Any())
// {
// // The requested record type was found.
// LogMessageCreate(Logging.LogMessageText.RESPONSE.ResolutionSucceded(Resolver.Domain, Question, requested));
// }
// else
// {
// // The requested record type was NOT found.
// if (question == DnsClient.DNS.QTYPE.ANY)
// {
// // The question is ANY, so the result is acceptable.
// LogMessageCreate(Logging.LogMessageText.RESPONSE.AnyResolutionSucceded(response.AnswerRecords));
// }
// else
// {
// // maybe CNAME
// }
// }
//}
#endregion
#region private
private Results.ResolutionResult Request(NameServerCollection authorities, out bool isCompleted)
{
// perform name server request
DnsClient.Request request;
IPAddress address = authorities.Selected.GetFirstAddress(Resolver.Options.IPVersion);
DnsClient.Response response = Resolver.LookUp(address, Question, out request);
Results.ResolutionResult result = new Results.ResolutionResult(this.NestingLevel, request, response, authorities);
// "Request took {0}ms."
LogMessageCreate(Logging.LogMessageText.RESPONSE.INFO.RequestDuration(result.Duration.TotalMilliseconds));
if (response.Header.AA)
{
// authoritative response
isCompleted = true;
}
else
{
// [RFC 1035]
// Name Error - Meaningful only for responses from an authoritative name server,
// this code signifies that the domain name referenced in the query does not exist.
// stop if the response was any other than NoError or NameError
isCompleted = !(
response.Header.RCODE == DnsClient.DNS.RCODE.NoError ||
response.Header.RCODE == DnsClient.DNS.RCODE.NameError);
}
return(result);
}
protected virtual void OnNextAuthorities(NameServer ns, NameServerCollection authorities)
{
foreach (IGrouping <int, NameServer> nsg in authorities.Groupings)
{
LogMessageCreate(Logging.LogMessageText.RESPONSE.INFO.NextAuthoritiesReceived(
ns.Name, nsg.First().Zone, authorities));
}
}
public static LogMessage ResolutionStart(DnsDomain name, NameServerCollection authorities)
{
if (authorities.ZoneName.Equals(DnsDomain.Root))
{
// "Starting resolution of '{0}' with a root name server."
return REQUEST.INFO.StartingResultion(name);
}
// "Starting resolution of '{0}' with a '{1}' authority name server."
return REQUEST.INFO.StartingResultion(name, authorities);
}
public static LogMessage ResolutionStart(DnsDomain name, NameServerCollection authorities)
{
if (authorities.ZoneName.Equals(DnsDomain.Root))
{
// "Starting resolution of '{0}' with a root name server."
return(REQUEST.INFO.StartingResultion(name));
}
// "Starting resolution of '{0}' with a '{1}' authority name server."
return(REQUEST.INFO.StartingResultion(name, authorities));
}
private Iterators.CNameIterator CreateCNameIterator(DnsDomain cname, NameServerCollection authorities)
{
// TODO
// apply authorties
Iterators.CNameIterator iterator = new CNameIterator(this, (DnsDomain)cname);
if (LogMessageCreated != null)
{
iterator.LogMessageCreated += new DnsClient.Logging.LogMessageEventHandler(OnSubIteratorLogMessage);
}
return(iterator);
}
private NameServerCollection GetResultAuthorities(Results.ResolutionResult result)
{
// get authority records from existing result
NameServerCollection authorities = NameServerCollection.Create(
result.Response.AuthorityRecords, result.Response.AdditionalRecords);
// save top level name server cache
if (!RootCacheState)
{
RootServers.Cache.Set(authorities.ZoneName, authorities);
RootCacheState = true;
}
return(authorities);
}
private NameServerCollection GetStartAuthorities()
{
NameServerCollection authorities = null;
// initial state:
// get cached top level name servers or root hints
if (Resolver.Options.UseRootCache)
{
authorities = RootServers.Cache.Get(Resolver.Domain);
}
if (authorities == null)
{
// either RootCache disabled or not found in cache
authorities = RootServers.RootHints;
RootCacheState = false;
}
return(authorities);
}
protected virtual void OnResolutionStart(NameServerCollection authorities)
{
// "Starting resolution of '{0}' with a '{1}' authority name server."
LogMessageCreate(Logging.LogMessageText.REQUEST.ResolutionStart(Resolver.Domain, authorities));
}
private Results.ResolutionResult Request(NameServerCollection authorities, out bool isCompleted)
{
// perform name server request
DnsClient.Request request;
IPAddress address = authorities.Selected.GetFirstAddress(Resolver.Options.IPVersion);
DnsClient.Response response = Resolver.LookUp(address, Question, out request);
Results.ResolutionResult result = new Results.ResolutionResult(this.NestingLevel, request, response, authorities);
// "Request took {0}ms."
LogMessageCreate(Logging.LogMessageText.RESPONSE.INFO.RequestDuration(result.Duration.TotalMilliseconds));
if (response.Header.AA)
{
// authoritative response
isCompleted = true;
}
else
{
// [RFC 1035]
// Name Error - Meaningful only for responses from an authoritative name server,
// this code signifies that the domain name referenced in the query does not exist.
// stop if the response was any other than NoError or NameError
isCompleted = !(
response.Header.RCODE == DnsClient.DNS.RCODE.NoError ||
response.Header.RCODE == DnsClient.DNS.RCODE.NameError);
}
return result;
}
private Iterators.CNameIterator CreateCNameIterator(DnsDomain cname, NameServerCollection authorities)
{
// TODO
// apply authorties
Iterators.CNameIterator iterator = new CNameIterator(this, (DnsDomain)cname);
if (LogMessageCreated != null)
{
iterator.LogMessageCreated += new DnsClient.Logging.LogMessageEventHandler(OnSubIteratorLogMessage);
}
return iterator;
}
protected virtual void OnResolutionStart(NameServerCollection authorities)
{
// "Starting resolution of '{0}' with a '{1}' authority name server."
LogMessageCreate(Logging.LogMessageText.REQUEST.ResolutionStart(Resolver.Domain, authorities));
}
protected virtual void OnResolutionContinue(NameServerCollection authorities)
{
// "Continuing resolution of '{0}' with a '{1}' authority."
LogMessageCreate(Logging.LogMessageText.REQUEST.INFO.ContinuingResultion(Resolver.Domain, authorities));
}
public static LogMessage NextAuthoritiesReceived(DnsDomain server, DnsDomain name, NameServerCollection nextAuthorities)
{
return Create(Resources.LogMessages.NextAuthoritiesReceived,
new object[] { server, name, nextAuthorities.Count });
}
protected virtual void OnAuthoritySelected(NameServerCollection authorities)
{
// "Name server '{0}' has been selected."
LogMessageCreate(Logging.LogMessageText.REQUEST.INFO.AuthoritySelected(authorities));
}
public static LogMessage AuthoritySelected(NameServerCollection authorities)
{
return(Create(Resources.LogMessages.AuthoritySelected, new object[] { authorities.Selected.Name }));
}
public static LogMessage StartingResultion(DnsDomain name, NameServerCollection authorities)
{
return Create(Resources.LogMessages.StartingResultion, new object[] { name, authorities.ZoneName });
}
public static LogMessage ContinuingResultion(DnsDomain domain, NameServerCollection authorities)
{
return Create(Resources.LogMessages.ContinuingResultion, new object[] { domain, authorities.ZoneName });
}
public static LogMessage AuthoritySelected(NameServerCollection authorities)
{
return Create(Resources.LogMessages.AuthoritySelected, new object[] { authorities.Selected.Name });
}
public QueryResult Process()
{
// [RFC 1034], 5.3.3. Algorithm
//
// 4. Analyze the response, either:
//
// a. if the response answers the question or contains a name
// error, cache the data as well as returning it back to
// the client.
//
// b. if the response contains a better delegation to other
// servers, cache the delegation information, and go to
// step 2.
//
// c. if the response shows a CNAME and that is not the
// answer itself, cache the CNAME, change the SNAME to the
// canonical name in the CNAME RR and go to step 1.
//
// d. if the response shows a servers failure or other
// bizarre contents, delete the server from the SLIST and
// go back to step 3.
//
// Step 4 involves analyzing responses. The resolver should be highly
// paranoid in its parsing of responses.
// Verify the question section matches the query.
if (Response.Questions.Count == 1)
{
DnsClient.DNS.Question q = Response.Questions.First();
if (!this.SNAME.Equals(q.QNAME) || this.STYPE != q.QTYPE)
{
throw new QueryException(QueryState.MissingQuestion);
}
}
else
{
throw new QueryException(QueryState.MissingQuestion);
}
// Check for unhandled RCODE.
if (!(Response.Header.RCODE == DnsClient.DNS.RCODE.NoError ||
Response.Header.RCODE == DnsClient.DNS.RCODE.NameError))
{
return(new QueryResult {
State = QueryState.UnexpectedRCode
});
}
// RCODE.NoError or RCODE.NameError
if (!Response.Header.AA)
{
// Non-Authoritative Answer
NameServerCollection nextAuthorities = FindAuthorities(SNAME);
if (nextAuthorities.Any())
{
// Referral response: authorities is not empty.
// Check for relevant answer RRs matching STYPE within additional RRs
IEnumerable <DnsClient.DNS.RR> additional = Response.AdditionalRecords.Where(
rr => SNAME.Equals(rr.Base.NAME)).OfQuestion(STYPE);
if (additional.Any())
{
// Found answer RRs matching the query.
return(new QueryResult
{
Answers = additional,
State = QueryState.NonAuthoritativeAnswer
});
}
return(new QueryResult
{
NextAuthorities = nextAuthorities,
State = QueryState.NextAuthorities
});
}
return(new QueryResult {
State = QueryState.MissingAuthorities
});
}
// Authoritative Answer
// Process CNAMEs unless the question is CNAME.
// Even on RCODE.NameError CNAMEs need to be applied
// (cf.: [RFC 2308], 2.1 - Name Error).
bool cnamed = false;
DnsDomain canonical = SNAME;
if (STYPE != DnsClient.DNS.QTYPE.CNAME)
{
// resolve internal CNAME chain
cnamed = FindCanonical(ref canonical);
}
if (Response.Header.RCODE == DnsClient.DNS.RCODE.NameError)
{
// RCODE.NameError
// [RFC 2308], 2.1 - Name Error
//
// Name errors (NXDOMAIN) are indicated by the presence of "Name Error"
// in the RCODE field. In this case the domain referred to by the QNAME
// does not exist. Note: the answer section may have SIG and CNAME RRs
// and the authority section may have SOA, NXT [RFC2065] and SIG RRsets.
//
// It is possible to distinguish between a referral and a NXDOMAIN
// response by the presense of NXDOMAIN in the RCODE regardless of the
// presence of NS or SOA records in the authority section.
return(new QueryResult
{
CanonicalName = cnamed ? canonical : null,
SOA = Response.AuthorityRecords.FirstOrDefault <
DnsClient.DNS.Records.SOA>(),
State = QueryState.NxDomain
});
}
// Authoritative RCODE.NoError
// Check for relevant answer RRs matching the canonical name and STYPE.
IEnumerable <DnsClient.DNS.RR> answers = Response.AnswerRecords.Where(
rr => canonical.Equals(rr.Base.NAME)).OfQuestion(STYPE);
if (answers.Any())
{
// Found answer RRs matching the query.
return(new QueryResult
{
CanonicalName = cnamed ? canonical : null,
Answers = answers,
State = QueryState.AuthoritativeAnswer
});
}
// NoData or referral CNAME response
// [RFC 2308], 2.2 - No Data
//
// It is possible to distinguish between a NODATA and a referral
// response by the presence of a SOA record in the authority section or
// the absence of NS records in the authority section.
DnsClient.DNS.Records.SOA soa = Response.AuthorityRecords.FirstOrDefault <
DnsClient.DNS.Records.SOA>();
NameServerCollection authorities = FindAuthorities(canonical);
if (!object.ReferenceEquals(null, soa) || authorities.Any())
{
// NODATA
// Do not treat as referral (cf.: [RFC 2308], 2.2 - No Data)
return(new QueryResult
{
SOA = soa,
CanonicalName = cnamed ? canonical : null,
State = QueryState.NoData
});
}
// Referral response: authorities is not empty.
if (cnamed)
{
// referral CNAME
return(new QueryResult
{
CanonicalName = canonical,
NextAuthorities = FindAuthorities(canonical),
State = QueryState.FollowCName
});
}
return(new QueryResult {
State = QueryState.EmptyResponse
});
}
protected virtual void OnResolutionContinue(NameServerCollection authorities)
{
// "Continuing resolution of '{0}' with a '{1}' authority."
LogMessageCreate(Logging.LogMessageText.REQUEST.INFO.ContinuingResultion(Resolver.Domain, authorities));
}
private NameServerCollection FindAuthorities(DnsDomain sname)
{
// NS RRs from Authority Section, resolved by Additional address RRs.
return(NameServerCollection.Find(
sname, Response.AuthorityRecords, Response.AdditionalRecords));
}
protected virtual void OnAuthoritySelected(NameServerCollection authorities)
{
// "Name server '{0}' has been selected."
LogMessageCreate(Logging.LogMessageText.REQUEST.INFO.AuthoritySelected(authorities));
}
protected virtual void OnNextAuthorities(NameServer ns, NameServerCollection authorities)
{
foreach (IGrouping<int, NameServer> nsg in authorities.Groupings)
{
LogMessageCreate(Logging.LogMessageText.RESPONSE.INFO.NextAuthoritiesReceived(
ns.Name, nsg.First().Zone, authorities));
}
}
internal AddressResolutionResult(int nestingLevel, DnsClient.Request request, DnsClient.Response response, NameServerCollection authorities)
: base(nestingLevel, request, response, authorities)
{
}
public static LogMessage StartingResultion(DnsDomain name, NameServerCollection authorities)
{
return(Create(Resources.LogMessages.StartingResultion, new object[] { name, authorities.ZoneName }));
}
public static LogMessage ContinuingResultion(DnsDomain domain, NameServerCollection authorities)
{
return(Create(Resources.LogMessages.ContinuingResultion, new object[] { domain, authorities.ZoneName }));
}
internal AddressResolutionResult(int nestingLevel, DnsClient.Request request, DnsClient.Response response, NameServerCollection authorities)
: base(nestingLevel, request, response, authorities)
{
}
public static LogMessage NextAuthoritiesReceived(DnsDomain server, DnsDomain name, NameServerCollection nextAuthorities)
{
return(Create(Resources.LogMessages.NextAuthoritiesReceived,
new object[] { server, name, nextAuthorities.Count }));
}