internal SpfQualifier CheckHost(SpfCheckHostParameter parameters)
{
if (String.IsNullOrEmpty(parameters.Sender))
{
return(SpfQualifier.PermError);
}
if (!parameters.Sender.Contains('@'))
{
parameters.Sender = "postmaster@" + parameters.Sender;
}
if (parameters.LoopCount > 15)
{
return(SpfQualifier.PermError);
}
if ((Terms == null) || (Terms.Count == 0))
{
return(SpfQualifier.Neutral);
}
foreach (SpfTerm term in Terms)
{
SpfQualifier qualifier = term.CheckHost(parameters);
if (qualifier != SpfQualifier.None)
{
return(qualifier);
}
}
return(SpfQualifier.Neutral);
}
public SpfCheckHostParameter(string newDomain, SpfCheckHostParameter oldParameters)
{
LoopCount = oldParameters.LoopCount + 1;
ClientAddress = oldParameters.ClientAddress;
ClientName = oldParameters.ClientName;
HeloName = oldParameters.HeloName;
CurrentDomain = newDomain;
Sender = oldParameters.Sender;
}
public SpfCheckHostParameter(string newDomain, SpfCheckHostParameter oldParameters)
{
LoopCount = oldParameters.LoopCount + 1;
ClientAddress = oldParameters.ClientAddress;
ClientName = oldParameters.ClientName;
HeloName = oldParameters.HeloName;
CurrentDomain = newDomain;
Sender = oldParameters.Sender;
}
internal static SpfQualifier CheckHost(string spfDomain, SpfCheckHostParameter parameters)
{
#region First try "real" spf records
List <SpfRecord> spfRecords = GetValidSpfRecords(spfDomain, RecordType.Spf);
if (spfRecords == null)
{
return(SpfQualifier.TempError);
}
else if (spfRecords.Count > 1)
{
return(SpfQualifier.PermError);
}
else if (spfRecords.Count == 1)
{
return(spfRecords[0].CheckHost(parameters));
}
#endregion
#region Then fallback to TXT records
spfRecords = GetValidSpfRecords(spfDomain, RecordType.Txt);
if (spfRecords == null)
{
return(SpfQualifier.TempError);
}
else if (spfRecords.Count > 1)
{
return(SpfQualifier.PermError);
}
else if (spfRecords.Count == 1)
{
return(spfRecords[0].CheckHost(parameters));
}
else
{
return(SpfQualifier.None);
}
#endregion
}
internal static SpfQualifier CheckHost(string spfDomain, SpfCheckHostParameter parameters)
{
#region First try "real" spf records
List<SpfRecord> spfRecords = GetValidSpfRecords(spfDomain, RecordType.Spf);
if (spfRecords == null)
{
return SpfQualifier.TempError;
}
else if (spfRecords.Count > 1)
{
return SpfQualifier.PermError;
}
else if (spfRecords.Count == 1)
{
return spfRecords[0].CheckHost(parameters);
}
#endregion
#region Then fallback to TXT records
spfRecords = GetValidSpfRecords(spfDomain, RecordType.Txt);
if (spfRecords == null)
{
return SpfQualifier.TempError;
}
else if (spfRecords.Count > 1)
{
return SpfQualifier.PermError;
}
else if (spfRecords.Count == 1)
{
return spfRecords[0].CheckHost(parameters);
}
else
{
return SpfQualifier.None;
}
#endregion
}
internal SpfQualifier CheckHost(SpfCheckHostParameter parameters)
{
if (String.IsNullOrEmpty(parameters.Sender))
return SpfQualifier.PermError;
if (!parameters.Sender.Contains('@'))
parameters.Sender = "postmaster@" + parameters.Sender;
if (parameters.LoopCount > 15)
return SpfQualifier.PermError;
if ((Terms == null) || (Terms.Count == 0))
return SpfQualifier.Neutral;
foreach (SpfTerm term in Terms)
{
SpfQualifier qualifier = term.CheckHost(parameters);
if (qualifier != SpfQualifier.None)
return qualifier;
}
return SpfQualifier.Neutral;
}
private static string ExpandMacro(Match pattern, SpfCheckHostParameter parameters)
{
switch (pattern.Value)
{
case "%%":
return("%");
case "%_":
return("_");
case "%-":
return("-");
default:
string letter;
switch (pattern.Groups["letter"].Value)
{
case "s":
letter = parameters.Sender;
break;
case "l":
// no boundary check needed, sender is validated on start of CheckHost
letter = parameters.Sender.Split('@')[0];
break;
case "o":
// no boundary check needed, sender is validated on start of CheckHost
letter = parameters.Sender.Split('@')[1];
break;
case "d":
letter = parameters.CurrentDomain;
break;
case "i":
letter = String.Join(".", parameters.ClientAddress.GetAddressBytes().Select(b => b.ToString()).ToArray());
break;
case "p":
letter = parameters.ClientName;
break;
case "v":
letter = (parameters.ClientAddress.AddressFamily == AddressFamily.InterNetworkV6) ? "ip6" : "in-addr";
break;
case "h":
letter = parameters.HeloName;
break;
case "c":
letter = parameters.ClientAddress.ToString();
break;
case "r":
letter = System.Net.Dns.GetHostName();
break;
case "t":
letter = ((int)(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc) - DateTime.Now).TotalSeconds).ToString();
break;
default:
return(null);
}
// only letter
if (pattern.Value.Length == 4)
{
return(letter);
}
char[] delimiters = pattern.Groups["delimiter"].Value.ToCharArray();
if (delimiters.Length == 0)
{
delimiters = new char[] { '.' }
}
;
string[] parts = letter.Split(delimiters);
if (pattern.Groups["reverse"].Value == "r")
{
parts = parts.Reverse().ToArray();
}
int count = Int32.MaxValue;
if (!String.IsNullOrEmpty(pattern.Groups["count"].Value))
{
count = Int32.Parse(pattern.Groups["count"].Value);
}
if (count < 1)
{
return(null);
}
count = Math.Min(count, parts.Length);
return(String.Join(".", parts, (parts.Length - count), count));
}
}
private static string ExpandDomain(string pattern, SpfCheckHostParameter parameters)
{
Regex regex = new Regex(@"(%%|%_|%-|%\{(?<letter>[slodiphcrtv])(?<count>\d*)(?<reverse>r?)(?<delimiter>[\.\-+,/=]*)})", RegexOptions.Compiled);
return(regex.Replace(pattern, match => ExpandMacro(match, parameters)));
}
internal SpfQualifier CheckHost(SpfCheckHostParameter parameters)
{
DnsMessage dnsMessage;
SpfMechanism spfMechanism = this as SpfMechanism;
if (spfMechanism != null)
{
switch (spfMechanism.Type)
{
case SpfMechanismType.All:
return(spfMechanism.Qualifier);
case SpfMechanismType.A:
bool?isAMatch = IsIpMatch(String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain, parameters.ClientAddress, spfMechanism.Prefix, spfMechanism.Prefix6);
if (!isAMatch.HasValue)
{
return(SpfQualifier.TempError);
}
if (isAMatch.Value)
{
return(spfMechanism.Qualifier);
}
break;
case SpfMechanismType.Mx:
dnsMessage = DnsClient.Default.Resolve(ExpandDomain(String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain, parameters), RecordType.Mx);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
return(SpfQualifier.TempError);
}
int mxCheckedCount = 0;
foreach (DnsRecordBase dnsRecord in dnsMessage.AnswerRecords)
{
MxRecord mxRecord = dnsRecord as MxRecord;
if (mxRecord != null)
{
if (++mxCheckedCount == 10)
{
break;
}
bool?isMxMatch = IsIpMatch(mxRecord.ExchangeDomainName, parameters.ClientAddress, spfMechanism.Prefix, spfMechanism.Prefix6);
if (!isMxMatch.HasValue)
{
return(SpfQualifier.TempError);
}
if (isMxMatch.Value)
{
return(spfMechanism.Qualifier);
}
}
}
break;
case SpfMechanismType.Ip4:
case SpfMechanismType.Ip6:
IPAddress compareAddress;
if (IPAddress.TryParse(spfMechanism.Domain, out compareAddress))
{
if (spfMechanism.Prefix.HasValue)
{
if (parameters.ClientAddress.GetNetworkAddress(spfMechanism.Prefix.Value).Equals(compareAddress.GetNetworkAddress(spfMechanism.Prefix.Value)))
{
return(spfMechanism.Qualifier);
}
}
else if (parameters.ClientAddress.Equals(compareAddress))
{
return(spfMechanism.Qualifier);
}
}
else
{
return(SpfQualifier.PermError);
}
break;
case SpfMechanismType.Ptr:
dnsMessage = DnsClient.Default.Resolve(parameters.ClientAddress.GetReverseLookupAddress(), RecordType.Ptr);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
return(SpfQualifier.TempError);
}
string ptrCompareName = String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain;
int ptrCheckedCount = 0;
if ((from ptrRecord in dnsMessage.AnswerRecords.OfType <PtrRecord>().TakeWhile(ptrRecord => ++ ptrCheckedCount != 10)
let isPtrMatch = IsIpMatch(ptrRecord.PointerDomainName, parameters.ClientAddress, 0, 0)
where isPtrMatch.HasValue && isPtrMatch.Value
select ptrRecord).Any(ptrRecord => ptrRecord.PointerDomainName.Equals(ptrCompareName, StringComparison.InvariantCultureIgnoreCase) || (ptrRecord.PointerDomainName.EndsWith("." + ptrCompareName, StringComparison.InvariantCultureIgnoreCase))))
{
return(spfMechanism.Qualifier);
}
break;
case SpfMechanismType.Exist:
if (String.IsNullOrEmpty(spfMechanism.Domain))
{
return(SpfQualifier.PermError);
}
dnsMessage = DnsClient.Default.Resolve(ExpandDomain(spfMechanism.Domain, parameters), RecordType.A);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
return(SpfQualifier.TempError);
}
if (dnsMessage.AnswerRecords.Count(record => (record.RecordType == RecordType.A)) > 0)
{
return(spfMechanism.Qualifier);
}
break;
case SpfMechanismType.Include:
if (String.IsNullOrEmpty(spfMechanism.Domain))
{
return(SpfQualifier.PermError);
}
string includeDomain = ExpandDomain(spfMechanism.Domain, parameters);
switch (SpfRecord.CheckHost(includeDomain, new SpfCheckHostParameter(includeDomain, parameters)))
{
case SpfQualifier.Pass:
return(spfMechanism.Qualifier);
case SpfQualifier.Fail:
case SpfQualifier.SoftFail:
case SpfQualifier.Neutral:
return(SpfQualifier.None);
case SpfQualifier.TempError:
return(SpfQualifier.TempError);
case SpfQualifier.PermError:
case SpfQualifier.None:
return(SpfQualifier.PermError);
}
break;
default:
return(SpfQualifier.PermError);
}
}
SpfModifier spfModifier = this as SpfModifier;
if (spfModifier != null)
{
switch (spfModifier.Type)
{
case SpfModifierType.Redirect:
if (String.IsNullOrEmpty(spfModifier.Domain))
{
return(SpfQualifier.PermError);
}
string redirectDomain = ExpandDomain(spfModifier.Domain, parameters);
return(SpfRecord.CheckHost(redirectDomain, new SpfCheckHostParameter(redirectDomain, parameters)));
case SpfModifierType.Exp:
break;
default:
return(SpfQualifier.PermError);
}
}
return(SpfQualifier.None);
}
private static string ExpandMacro(Match pattern, SpfCheckHostParameter parameters)
{
switch (pattern.Value)
{
case "%%":
return "%";
case "%_":
return "_";
case "%-":
return "-";
default:
string letter;
switch (pattern.Groups["letter"].Value)
{
case "s":
letter = parameters.Sender;
break;
case "l":
// no boundary check needed, sender is validated on start of CheckHost
letter = parameters.Sender.Split('@')[0];
break;
case "o":
// no boundary check needed, sender is validated on start of CheckHost
letter = parameters.Sender.Split('@')[1];
break;
case "d":
letter = parameters.CurrentDomain;
break;
case "i":
letter = String.Join(".", parameters.ClientAddress.GetAddressBytes().Select(b => b.ToString()).ToArray());
break;
case "p":
letter = parameters.ClientName;
break;
case "v":
letter = (parameters.ClientAddress.AddressFamily == AddressFamily.InterNetworkV6) ? "ip6" : "in-addr";
break;
case "h":
letter = parameters.HeloName;
break;
case "c":
letter = parameters.ClientAddress.ToString();
break;
case "r":
letter = System.Net.Dns.GetHostName();
break;
case "t":
letter = ((int) (new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc) - DateTime.Now).TotalSeconds).ToString();
break;
default:
return null;
}
// only letter
if (pattern.Value.Length == 4)
return letter;
char[] delimiters = pattern.Groups["delimiter"].Value.ToCharArray();
if (delimiters.Length == 0)
delimiters = new char[] { '.' };
string[] parts = letter.Split(delimiters);
if (pattern.Groups["reverse"].Value == "r")
parts = parts.Reverse().ToArray();
int count = Int32.MaxValue;
if (!String.IsNullOrEmpty(pattern.Groups["count"].Value))
{
count = Int32.Parse(pattern.Groups["count"].Value);
}
if (count < 1)
return null;
count = Math.Min(count, parts.Length);
return String.Join(".", parts, (parts.Length - count), count);
}
}
private static string ExpandDomain(string pattern, SpfCheckHostParameter parameters)
{
Regex regex = new Regex(@"(%%|%_|%-|%\{(?<letter>[slodiphcrtv])(?<count>\d*)(?<reverse>r?)(?<delimiter>[\.\-+,/=]*)})", RegexOptions.Compiled);
return regex.Replace(pattern, match => ExpandMacro(match, parameters));
}
internal SpfQualifier CheckHost(SpfCheckHostParameter parameters)
{
DnsMessage dnsMessage;
SpfMechanism spfMechanism = this as SpfMechanism;
if (spfMechanism != null)
{
switch (spfMechanism.Type)
{
case SpfMechanismType.All:
return spfMechanism.Qualifier;
case SpfMechanismType.A:
bool? isAMatch = IsIpMatch(String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain, parameters.ClientAddress, spfMechanism.Prefix, spfMechanism.Prefix6);
if (!isAMatch.HasValue)
return SpfQualifier.TempError;
if (isAMatch.Value)
{
return spfMechanism.Qualifier;
}
break;
case SpfMechanismType.Mx:
dnsMessage = DnsClient.Default.Resolve(ExpandDomain(String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain, parameters), RecordType.Mx);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
return SpfQualifier.TempError;
int mxCheckedCount = 0;
foreach (DnsRecordBase dnsRecord in dnsMessage.AnswerRecords)
{
MxRecord mxRecord = dnsRecord as MxRecord;
if (mxRecord != null)
{
if (++mxCheckedCount == 10)
break;
bool? isMxMatch = IsIpMatch(mxRecord.ExchangeDomainName, parameters.ClientAddress, spfMechanism.Prefix, spfMechanism.Prefix6);
if (!isMxMatch.HasValue)
return SpfQualifier.TempError;
if (isMxMatch.Value)
{
return spfMechanism.Qualifier;
}
}
}
break;
case SpfMechanismType.Ip4:
case SpfMechanismType.Ip6:
IPAddress compareAddress;
if (IPAddress.TryParse(spfMechanism.Domain, out compareAddress))
{
if (spfMechanism.Prefix.HasValue)
{
if (parameters.ClientAddress.GetNetworkAddress(spfMechanism.Prefix.Value).Equals(compareAddress.GetNetworkAddress(spfMechanism.Prefix.Value)))
{
return spfMechanism.Qualifier;
}
}
else if (parameters.ClientAddress.Equals(compareAddress))
{
return spfMechanism.Qualifier;
}
}
else
{
return SpfQualifier.PermError;
}
break;
case SpfMechanismType.Ptr:
dnsMessage = DnsClient.Default.Resolve(parameters.ClientAddress.GetReverseLookupAddress(), RecordType.Ptr);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
return SpfQualifier.TempError;
string ptrCompareName = String.IsNullOrEmpty(spfMechanism.Domain) ? parameters.CurrentDomain : spfMechanism.Domain;
int ptrCheckedCount = 0;
if ((from ptrRecord in dnsMessage.AnswerRecords.OfType<PtrRecord>().TakeWhile(ptrRecord => ++ptrCheckedCount != 10)
let isPtrMatch = IsIpMatch(ptrRecord.PointerDomainName, parameters.ClientAddress, 0, 0)
where isPtrMatch.HasValue && isPtrMatch.Value
select ptrRecord).Any(ptrRecord => ptrRecord.PointerDomainName.Equals(ptrCompareName, StringComparison.InvariantCultureIgnoreCase) || (ptrRecord.PointerDomainName.EndsWith("." + ptrCompareName, StringComparison.InvariantCultureIgnoreCase))))
{
return spfMechanism.Qualifier;
}
break;
case SpfMechanismType.Exist:
if (String.IsNullOrEmpty(spfMechanism.Domain))
return SpfQualifier.PermError;
dnsMessage = DnsClient.Default.Resolve(ExpandDomain(spfMechanism.Domain, parameters), RecordType.A);
if ((dnsMessage == null) || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
return SpfQualifier.TempError;
if (dnsMessage.AnswerRecords.Count(record => (record.RecordType == RecordType.A)) > 0)
{
return spfMechanism.Qualifier;
}
break;
case SpfMechanismType.Include:
if (String.IsNullOrEmpty(spfMechanism.Domain))
return SpfQualifier.PermError;
string includeDomain = ExpandDomain(spfMechanism.Domain, parameters);
switch (SpfRecord.CheckHost(includeDomain, new SpfCheckHostParameter(includeDomain, parameters)))
{
case SpfQualifier.Pass:
return spfMechanism.Qualifier;
case SpfQualifier.Fail:
case SpfQualifier.SoftFail:
case SpfQualifier.Neutral:
return SpfQualifier.None;
case SpfQualifier.TempError:
return SpfQualifier.TempError;
case SpfQualifier.PermError:
case SpfQualifier.None:
return SpfQualifier.PermError;
}
break;
default:
return SpfQualifier.PermError;
}
}
SpfModifier spfModifier = this as SpfModifier;
if (spfModifier != null)
{
switch (spfModifier.Type)
{
case SpfModifierType.Redirect:
if (String.IsNullOrEmpty(spfModifier.Domain))
return SpfQualifier.PermError;
string redirectDomain = ExpandDomain(spfModifier.Domain, parameters);
return SpfRecord.CheckHost(redirectDomain, new SpfCheckHostParameter(redirectDomain, parameters));
case SpfModifierType.Exp:
break;
default:
return SpfQualifier.PermError;
}
}
return SpfQualifier.None;
}
