Class PacketBuilder

Namespace: VpnHood.Net.Packets

Assembly: VpnHood.Net.Packets.dll

Provides methods that parse IP packets and build new ones: UDP, TCP, ICMP and the replies a router or a host sends.

public static class PacketBuilder

Inheritance: object

PacketBuilder

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Examples

using var ipPacket = PacketBuilder.BuildUdp(
    new IPEndPoint(IPAddress.Parse("10.0.0.2"), 5353),
    new IPEndPoint(IPAddress.Parse("10.0.0.1"), 53),
    "hello"u8);

ipPacket.UpdateAllChecksums(); // BuildUdp computes no checksum itself
var bytes = ipPacket.Buffer; // the packet's own bytes, ready for a TUN device

Remarks

A built packet owns the memory it is built in: an array rented from Shared, or memory from the MemoryPool<T> given. Dispose it to return the memory. Its time to live is 64. A method with an updateChecksum parameter computes the checksums when it is true; the others compute none, so call UpdateAllChecksums(IpPacket) before sending.

Methods

Attach(PacketMemory)

Parses the IP packet at the start of some memory, without copying it: the packet reads and writes the memory.

public static IpPacket Attach(PacketMemory memory)

Parameters

memory PacketMemory: The memory, which holds the packet from its first byte and may be longer: a Memory<T> or an array the caller keeps, or memory given to the packet (see PacketMemory), which stays the caller's when parsing fails.

Returns

IpPacket: An IpV4Packet or IpV6Packet; dispose it to return the memory it was given.

Exceptions

NotSupportedException: The version is neither 4 nor 6.
ArgumentException: The bytes are no valid IP packet.
IndexOutOfRangeException: The memory is empty.

BuildDns(IPAddress, IPAddress, int, int, string, ushort?)

Builds an IP packet that carries a DNS query for a name's IPv4 addresses (type A, class IN, recursion desired) over UDP.

public static IpPacket BuildDns(IPAddress sourceAddress, IPAddress destinationAddress, int sourcePort, int destinationPort, string host, ushort? queryId = null)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The DNS server's address, of the same IP version.
sourcePort int: The source port.
destinationPort int: The DNS server's port, usually 53.
host string: The name to look up.
queryId ushort?: The query's ID, or null for a random one.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildDns(IPEndPoint, IPEndPoint, string, ushort?)

Builds an IP packet that carries a DNS query for a name's IPv4 addresses (type A, class IN, recursion desired) over UDP.

public static IpPacket BuildDns(IPEndPoint sourceEndPoint, IPEndPoint destinationEndPoint, string host, ushort? queryId = null)

Parameters

sourceEndPoint IPEndPoint: The source address and port.
destinationEndPoint IPEndPoint: The DNS server's address and port, of the same IP version.
host string: The name to look up.
queryId ushort?: The query's ID, or null for a random one.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildIcmpEchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv4 or ICMPv6 echo reply, the answer to a ping, by the addresses' IP version.

public static IpPacket BuildIcmpEchoReply(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The destination address, of the same IP version.
payload ReadOnlySpan<byte>: The echo's data, which is copied in: the request's data, for a reply to it.
identifier ushort: The echo's identifier: the request's, for a reply to it.
sequenceNumber ushort: The echo's sequence number: the request's, for a reply to it.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: The addresses are of different IP versions.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildIcmpEchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv4 or ICMPv6 echo request, a ping, by the addresses' IP version.

public static IpPacket BuildIcmpEchoRequest(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The destination address, of the same IP version.
payload ReadOnlySpan<byte>: The echo's data, which is copied in.
identifier ushort: The echo's identifier.
sequenceNumber ushort: The echo's sequence number.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: The addresses are of different IP versions.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildIcmpPacketTooBigReply(IpPacket, int, bool)

Builds the ICMP error that tells a packet's sender it is too big for the next link: ICMPv6 "packet too big", or ICMPv4 "fragmentation needed".

public static IpPacket BuildIcmpPacketTooBigReply(IpPacket ipPacket, int mtu, bool updateChecksum = true)

Parameters

ipPacket IpPacket: The packet that is too big. The error goes from its destination to its source and carries its start.
mtu int: The next link's MTU in bytes, which the error carries; ICMPv4 carries its low 16 bits.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The error packet; dispose it to return its memory.

Exceptions

ObjectDisposedException: ipPacket is disposed.

BuildIcmpUnreachablePortReply(IpPacket, bool)

Builds the ICMP error that tells a packet's sender its destination port is unreachable.

public static IpPacket BuildIcmpUnreachablePortReply(IpPacket ipPacket, bool updateChecksum = true)

Parameters

ipPacket IpPacket: The packet that cannot be delivered. The error goes from its destination to its source and carries its start.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The error packet; dispose it to return its memory.

Exceptions

ObjectDisposedException: ipPacket is disposed.

BuildIcmpUnreachableReply(IpPacket, bool)

Builds the ICMP error that tells a packet's sender its destination is unreachable: ICMPv4 "host unreachable", or ICMPv6 "address unreachable".

public static IpPacket BuildIcmpUnreachableReply(IpPacket ipPacket, bool updateChecksum = true)

Parameters

ipPacket IpPacket: The packet that cannot be delivered. The error goes from its destination to its source and carries its start.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The error packet; dispose it to return its memory.

Exceptions

ObjectDisposedException: ipPacket is disposed.

BuildIcmpV4(IPAddress, IPAddress, ReadOnlySpan<byte>)

Builds an IPv4 packet that carries an ICMPv4 message, with its type, code and message-specific field zero.

public static IpPacket BuildIcmpV4(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload)

Parameters

sourceAddress IPAddress: The source address, IPv4.
destinationAddress IPAddress: The destination address, IPv4.
payload ReadOnlySpan<byte>: The message's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

Type zero is an echo reply: set Type through ExtractIcmpV4(IpPacket). No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.

BuildIcmpV4EchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv4 echo reply, the answer to a ping.

public static IpPacket BuildIcmpV4EchoReply(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address, IPv4.
destinationAddress IPAddress: The destination address, IPv4.
payload ReadOnlySpan<byte>: The echo's data, which is copied in: the request's data, for a reply to it.
identifier ushort: The echo's identifier: the request's, for a reply to it.
sequenceNumber ushort: The echo's sequence number: the request's, for a reply to it.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: An address is not IPv4.

BuildIcmpV4EchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv4 echo request, a ping.

public static IpPacket BuildIcmpV4EchoRequest(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address, IPv4.
destinationAddress IPAddress: The destination address, IPv4.
payload ReadOnlySpan<byte>: The echo's data, which is copied in.
identifier ushort: The echo's identifier.
sequenceNumber ushort: The echo's sequence number.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: An address is not IPv4.

BuildIcmpV4Error(IpPacket, IcmpV4Type, IcmpV4Code, uint, bool)

Builds an ICMPv4 error about a packet, from its destination back to its source.

public static IpPacket BuildIcmpV4Error(IpPacket ipPacket, IcmpV4Type icmpV4Type, IcmpV4Code code, uint messageSpecific, bool updateChecksum)

Parameters

ipPacket IpPacket: The IPv4 packet the error is about.
icmpV4Type IcmpV4Type: The error's type.
code IcmpV4Code: The error's code.
messageSpecific uint: The 4 bytes after the checksum, such as the next-hop MTU in the low 16 bits.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The error packet; dispose it to return its memory.

Remarks

The error carries the packet's IP header and up to the first 8 bytes of its payload, as RFC 792 asks.

Exceptions

ArgumentNullException: ipPacket is null.
ObjectDisposedException: ipPacket is disposed.

BuildIcmpV6(IPAddress, IPAddress, ReadOnlySpan<byte>)

Builds an IPv6 packet that carries an ICMPv6 message, with its type, code and message-specific field zero.

public static IpPacket BuildIcmpV6(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload)

Parameters

sourceAddress IPAddress: The source address, IPv6.
destinationAddress IPAddress: The destination address, IPv6.
payload ReadOnlySpan<byte>: The message's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

Set Type through ExtractIcmpV6(IpPacket). No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions.

BuildIcmpV6EchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv6 echo reply, the answer to a ping.

public static IpPacket BuildIcmpV6EchoReply(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address, IPv6.
destinationAddress IPAddress: The destination address, IPv6.
payload ReadOnlySpan<byte>: The echo's data, which is copied in: the request's data, for a reply to it.
identifier ushort: The echo's identifier: the request's, for a reply to it.
sequenceNumber ushort: The echo's sequence number: the request's, for a reply to it.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: An address is not IPv6.

BuildIcmpV6EchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Builds an ICMPv6 echo request, a ping.

public static IpPacket BuildIcmpV6EchoRequest(IPAddress sourceAddress, IPAddress destinationAddress, ReadOnlySpan<byte> payload, ushort identifier = 0, ushort sequenceNumber = 0, bool updateChecksum = true)

Parameters

sourceAddress IPAddress: The source address, IPv6.
destinationAddress IPAddress: The destination address, IPv6.
payload ReadOnlySpan<byte>: The echo's data, which is copied in.
identifier ushort: The echo's identifier.
sequenceNumber ushort: The echo's sequence number.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The packet; dispose it to return its memory.

Exceptions

ArgumentException: An address is not IPv6.

BuildIcmpV6Error(IpPacket, IcmpV6Type, IcmpV6Code, uint, bool)

Builds an ICMPv6 error about a packet, from its destination back to its source.

public static IpPacket BuildIcmpV6Error(IpPacket ipPacket, IcmpV6Type icmpV6Type, IcmpV6Code code, uint messageSpecific, bool updateChecksum = true)

Parameters

ipPacket IpPacket: The IPv6 packet the error is about.
icmpV6Type IcmpV6Type: The error's type.
code IcmpV6Code: The error's code.
messageSpecific uint: The 4 bytes after the checksum, such as the MTU of a "packet too big" error.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The error packet; dispose it to return its memory.

Remarks

The error carries the packet's first 1232 bytes, or the whole packet when it is shorter, so that the error is no longer than 1280 bytes, IPv6's minimum MTU, as RFC 4443 asks.

Exceptions

ArgumentNullException: ipPacket is null.
ObjectDisposedException: ipPacket is disposed.

BuildIp(IPAddress, IPAddress, IpProtocol, int, MemoryPool<byte>?)

Builds an IP packet with an empty payload of a given length, for the caller to fill.

public static IpPacket BuildIp(IPAddress sourceAddress, IPAddress destinationAddress, IpProtocol protocol, int payloadLength, MemoryPool<byte>? memoryPool = null)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The destination address, of the same IP version.
protocol IpProtocol: The protocol of the payload.
payloadLength int: The payload's length in bytes; at most 65515 for IPv4 and 65535 for IPv6.
memoryPool MemoryPool<byte>: The pool to rent the packet's memory from, or null for an array of Shared.

Returns

IpPacket: The packet, with its payload zero; dispose it to return its memory.

Exceptions

ArgumentException: The addresses are of different IP versions, or the payload is longer than their IP version allows.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildIp(ReadOnlySpan<byte>, ReadOnlySpan<byte>, IpProtocol, int, MemoryPool<byte>?)

Builds an IP packet with an empty payload of a given length, for the caller to fill, from raw address bytes.

public static IpPacket BuildIp(ReadOnlySpan<byte> sourceAddress, ReadOnlySpan<byte> destinationAddress, IpProtocol protocol, int payloadLength, MemoryPool<byte>? memoryPool = null)

Parameters

sourceAddress ReadOnlySpan<byte>: The source address: 4 bytes for IPv4, 16 for IPv6.
destinationAddress ReadOnlySpan<byte>: The destination address, of the same length.
protocol IpProtocol: The protocol of the payload.
payloadLength int: The payload's length in bytes; at most 65515 for IPv4 and 65535 for IPv6.
memoryPool MemoryPool<byte>: The pool to rent the packet's memory from, or null for an array of Shared.

Returns

IpPacket: The packet, with its payload zero; dispose it to return its memory.

Exceptions

ArgumentException: The addresses differ in length, or the payload is longer than their IP version allows.
NotSupportedException: The addresses are neither 4 nor 16 bytes long.

BuildIp(IpAddressValue, IpAddressValue, IpProtocol, int, MemoryPool<byte>?)

Builds an IP packet with an empty payload of a given length, for the caller to fill, from address values.

public static IpPacket BuildIp(IpAddressValue sourceAddress, IpAddressValue destinationAddress, IpProtocol protocol, int payloadLength, MemoryPool<byte>? memoryPool = null)

Parameters

sourceAddress IpAddressValue: The source address.
destinationAddress IpAddressValue: The destination address, of the same IP version.
protocol IpProtocol: The protocol of the payload.
payloadLength int: The payload's length in bytes; at most 65515 for IPv4 and 65535 for IPv6.
memoryPool MemoryPool<byte>: The pool to rent the packet's memory from, or null for an array of Shared.

Returns

IpPacket: The packet, with its payload zero; dispose it to return its memory.

Exceptions

ArgumentException: The addresses are of different IP versions, or the payload is longer than their IP version allows.
NotSupportedException: The addresses hold no address.

BuildTcp(IPAddress, IPAddress, int, int, ReadOnlySpan<byte>, ReadOnlySpan<byte>)

Builds an IP packet that carries a TCP segment, with its flags, numbers and window zero.

public static IpPacket BuildTcp(IPAddress sourceAddress, IPAddress destinationAddress, int sourcePort, int destinationPort, ReadOnlySpan<byte> options, ReadOnlySpan<byte> payload)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The destination address, of the same IP version.
sourcePort int: The source port, from 0 to 65535.
destinationPort int: The destination port, from 0 to 65535.
options ReadOnlySpan<byte>: The TCP options, a multiple of 4 bytes up to 40, which are copied in.
payload ReadOnlySpan<byte>: The segment's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.
ArgumentOutOfRangeException: options is longer than 40 bytes or not a multiple of 4.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildTcp(IPEndPoint, IPEndPoint, ReadOnlySpan<byte>, ReadOnlySpan<byte>)

Builds an IP packet that carries a TCP segment, with its flags, numbers and window zero.

public static IpPacket BuildTcp(IPEndPoint sourceEndPoint, IPEndPoint destinationEndPoint, ReadOnlySpan<byte> options, ReadOnlySpan<byte> payload)

Parameters

sourceEndPoint IPEndPoint: The source address and port.
destinationEndPoint IPEndPoint: The destination address and port, of the same IP version.
options ReadOnlySpan<byte>: The TCP options, a multiple of 4 bytes up to 40, which are copied in.
payload ReadOnlySpan<byte>: The segment's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.
ArgumentOutOfRangeException: options is longer than 40 bytes or not a multiple of 4.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildTcp(IpEndPointValue, IpEndPointValue, ReadOnlySpan<byte>, ReadOnlySpan<byte>)

Builds an IP packet that carries a TCP segment, with its flags, numbers and window zero.

public static IpPacket BuildTcp(IpEndPointValue sourceEndPoint, IpEndPointValue destinationEndPoint, ReadOnlySpan<byte> options, ReadOnlySpan<byte> payload)

Parameters

sourceEndPoint IpEndPointValue: The source address and port.
destinationEndPoint IpEndPointValue: The destination address and port, of the same IP version.
options ReadOnlySpan<byte>: The TCP options, a multiple of 4 bytes up to 40, which are copied in.
payload ReadOnlySpan<byte>: The segment's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.
ArgumentOutOfRangeException: options is longer than 40 bytes or not a multiple of 4.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildTcpResetReply(IpPacket, bool)

Builds the TCP reset (RST) that refuses a TCP packet, from its destination back to its source.

public static IpPacket BuildTcpResetReply(IpPacket ipPacket, bool updateChecksum = true)

Parameters

ipPacket IpPacket: The TCP packet to refuse.
updateChecksum bool: true to compute the checksums; false to leave them zero.

Returns

IpPacket: The reset packet; dispose it to return its memory.

Remarks

A reset for a SYN without ACK acknowledges it: sequence number 0, acknowledgment number the SYN's sequence number plus 1. For any other packet, the reset's sequence number is the packet's acknowledgment number, with no ACK.

Exceptions

ArgumentNullException: ipPacket is null.
ArgumentException: ipPacket does not carry TCP, or its TCP segment is invalid.
InvalidDataException: ipPacket is a fragment.

BuildUdp(IPAddress, IPAddress, int, int, ReadOnlySpan<byte>)

Builds an IP packet that carries a UDP datagram.

public static IpPacket BuildUdp(IPAddress sourceAddress, IPAddress destinationAddress, int sourcePort, int destinationPort, ReadOnlySpan<byte> payload)

Parameters

sourceAddress IPAddress: The source address.
destinationAddress IPAddress: The destination address, of the same IP version.
sourcePort int: The source port, from 0 to 65535.
destinationPort int: The destination port, from 0 to 65535.
payload ReadOnlySpan<byte>: The datagram's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

BuildUdp(IPEndPoint, IPEndPoint, ReadOnlySpan<byte>)

Builds an IP packet that carries a UDP datagram.

public static IpPacket BuildUdp(IPEndPoint sourceEndPoint, IPEndPoint destinationEndPoint, ReadOnlySpan<byte> payload)

Parameters

sourceEndPoint IPEndPoint: The source address and port.
destinationEndPoint IPEndPoint: The destination address and port, of the same IP version.
payload ReadOnlySpan<byte>: The datagram's payload, which is copied in.

Returns

IpPacket: The packet; dispose it to return its memory.

Remarks

No checksum is computed: call UpdateAllChecksums(IpPacket) before sending.

Exceptions

ArgumentException: The addresses are of different IP versions, or the packet would be too large.
NotSupportedException: The addresses are neither IPv4 nor IPv6.

Parse(ReadOnlySpan<byte>, MemoryPool<byte>?)

Parses the IP packet at the start of some bytes into a copy that the returned packet owns.

public static IpPacket Parse(ReadOnlySpan<byte> buffer, MemoryPool<byte>? memoryPool = null)

Parameters

buffer ReadOnlySpan<byte>: The bytes, which hold the packet from the first byte and may be longer.
memoryPool MemoryPool<byte>: The pool to rent the copy's memory from, or null for an array of Shared.

Returns

IpPacket: An IpV4Packet or IpV6Packet; dispose it to return its memory.

Examples

// Parse copies the received bytes into pooled memory; PacketBuilder.Attach would read them in place
using var ipPacket = PacketBuilder.Parse(received);
Console.WriteLine($"{ipPacket.SourceAddress} -> {ipPacket.DestinationAddress}, {ipPacket.Protocol}");

if (ipPacket.Protocol == IpProtocol.Udp && !ipPacket.IsFragment) {
    var udp = ipPacket.ExtractUdp(); // a view over the packet's bytes, not a copy
    Console.WriteLine($"UDP {udp.SourcePort} -> {udp.DestinationPort}, {udp.Payload.Length} bytes, " +
                      $"checksum valid: {udp.IsChecksumValid(ipPacket)}");
}

Exceptions

ArgumentException: The bytes are no valid IP packet.
ArgumentOutOfRangeException: buffer is shorter than the packet's length field says.
NotSupportedException: The version is neither 4 nor 6.
IndexOutOfRangeException: buffer is empty.

Table of Contents

Class PacketBuilder

Examples

Remarks

Methods

Attach(PacketMemory)

Parameters

Returns

Exceptions

BuildDns(IPAddress, IPAddress, int, int, string, ushort?)

Parameters

Returns

Remarks

Exceptions

BuildDns(IPEndPoint, IPEndPoint, string, ushort?)

Parameters

Returns

Remarks

Exceptions

BuildIcmpEchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpEchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpPacketTooBigReply(IpPacket, int, bool)

Parameters

Returns

Exceptions

BuildIcmpUnreachablePortReply(IpPacket, bool)

Parameters

Returns

Exceptions

BuildIcmpUnreachableReply(IpPacket, bool)

Parameters

Returns

Exceptions

BuildIcmpV4(IPAddress, IPAddress, ReadOnlySpan<byte>)

Parameters

Returns

Remarks

Exceptions

BuildIcmpV4EchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpV4EchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpV4Error(IpPacket, IcmpV4Type, IcmpV4Code, uint, bool)

Parameters

Returns

Remarks

Exceptions

BuildIcmpV6(IPAddress, IPAddress, ReadOnlySpan<byte>)

Parameters

Returns

Remarks

Exceptions

BuildIcmpV6EchoReply(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpV6EchoRequest(IPAddress, IPAddress, ReadOnlySpan<byte>, ushort, ushort, bool)

Parameters

Returns

Exceptions

BuildIcmpV6Error(IpPacket, IcmpV6Type, IcmpV6Code, uint, bool)

Parameters

Returns

Remarks

Exceptions

BuildIp(IPAddress, IPAddress, IpProtocol, int, MemoryPool<byte>?)

Parameters

Returns

Exceptions

BuildIp(ReadOnlySpan<byte>, ReadOnlySpan<byte>, IpProtocol, int, MemoryPool<byte>?)