TCP traceroute using RST and SYN-ACK to determine destination reachability

1. A method implemented by a traceroute application implementing a modified Transmission Control Protocol (TCP) stack in a processing device, the method comprising:

sending a plurality of TCP packets via a raw socket to perform a trace to a destination;

receiving responses to the plurality of TCP packets;

inspecting responses consumed by the modified TCP stack, wherein the modified TCP stack is adapted to recognize TCP traceroute traffic;

recognizing one of a Synchronize-Acknowledgment (SYN-ACK) or a Reset (RST) from the destination in the responses based on the inspecting;

responsive to recognizing the SYN-ACK or RST in the responses, diverting the SYN-ACK or RST responses to the raw socket; and

aggregating the responses by the traceroute application to determine details of a service path from the processing device to the destination.

2. The method of claim 1 , wherein the plurality of TCP packets include TCP Synchronize (SYN) messages, and the responses include TCP SYN-Acknowledgement (ACK) or Reset (RST) messages.

3. The method of claim 2 , further comprising receiving, at the modified TCP stack in the processing device, a TCP SYN-ACK message from the destination; and

sending a TCP RST packet to the destination based on the modified TCP stack recognizing the TCP SYN-ACL message.

4. The method of claim 3 , wherein a TCP checksum, sequence, and ACK in the TCP RST packet are implemented by the traceroute application.

5. The method of claim 1 , wherein the raw socket is used in lieu of a TCP socket to determine the reachability to the destination when TCP traceroute traffic is recognized based on the scanning of the TCP stack.

6. The method of claim 1 , wherein a port for the raw socket is allocated by the TCP stack from a pool of ports based on the destination.

7. A non-transitory computer-readable medium comprising instructions that, when executed, cause one or more processors associated with a processing device that executes a traceroute application implementing a modified Transmission Control Protocol (TCP) stack to perform steps of:

sending a plurality of TCP packets via a raw socket to perform a trace to a destination;

receiving responses to the plurality of TCP packets;

inspecting responses consumed by the modified TCP stack, wherein the modified TCP stack is adapted to recognize TCP traceroute traffic;

recognizing one of a Synchronize-Acknowledgment (SYN-ACK) or a Reset (RST) from the destination in the responses based on the inspecting;

responsive to recognizing the SYN-ACK or RST in the responses, diverting the SYN-ACK or RST responses to the raw socket; and

aggregating the responses by the traceroute application to determine details of a service path from the processing device to the destination.

8. The non-transitory computer-readable medium of claim 7 , wherein the plurality of TCP packets include TCP Synchronize (SYN) messages, and the responses include TCP SYN-Acknowledgement (ACK) or Reset (RST) messages.

9. The non-transitory computer-readable medium of claim 8 , wherein the steps further include

receiving, at the modified TCP stack in the processing device, a TCP SYN-ACK message from the destination; and

sending a TCP RST packet to the destination based on the modified TCP stack recognizing the TCP SYN-ACK message.

10. The non-transitory computer-readable medium of claim 9 , wherein a TCP checksum, sequence, and ACK in the TCP RST packet are implemented by the traceroute application.

11. The non-transitory computer-readable medium of claim 7 , wherein the raw socket is used in lieu of a TCP socket to determine the reachability to the destination when TCP traceroute traffic is recognized based on the scanning of the TCP stack.

12. The non-transitory computer-readable medium of claim 7 , wherein a port for the raw socket is allocated by the TCP stack from a pool of ports based on the destination.

13. A processing device with a traceroute application that implements a modified Transmission Control Protocol (TCP) stack, the processing device comprising:

one or more processors and memory comprising instructions that, when executed, cause the one or more processors to

send a plurality of TCP packets via a raw socket to perform a trace to a destination;

receive responses to the plurality of TCP packets;

inspect responses consumed by the modified TCP stack, wherein the modified TCP stack is adapted to recognize TCP traceroute traffic;

recognize one of a Synchronize-Acknowledgment (SYN-ACK) or a Reset (RST) from the destination in the responses based on the inspecting;

responsive to recognizing the SYN-ACK or RST in the responses, divert the SYN-ACK or RST responses to the raw socket; and

aggregate the responses by the traceroute application to determine details of a service path from the processing device to the destination.

14. The processing device of claim 13 , wherein the plurality of TCP packets include TCP Synchronize (SYN) messages, and the responses include TCP SYN-Acknowledgement (ACK) or Reset (RST) messages.

15. The processing device of claim 14 , wherein the instructions that, when executed, cause the one or more processors to

receive, at the modified TCP stack in the processing device, a TCP SYN-ACK message from the destination; and

send a TCP RST packet to the destination based on the modified TCP stack recognizing the TCP SYN-ACK message.

16. The processing device of claim 15 , wherein a TCP checksum, sequence, and ACK in the TCP RST packet are implemented by the traceroute application.

17. The processing device of claim 13 , wherein the raw socket is used in lieu of a TCP socket to determine the reachability to the destination when TCP traceroute traffic is recognized based on the scanning of the TCP stack.

18. The processing device of claim 13 , wherein a port for the raw socket is allocated by the TCP stack from a pool of ports based on the destination.