GRE tunneling with reduced packet encryption at intermediate routers using loose source routing

1. A method, comprising:

receiving, by a network node, a packet that includes an outer header,

wherein a source address of the outer header identifies a tunnel endpoint associated with a transmitting network node, and a destination address of the outer header identifies a tunnel endpoint associated with the network node,

wherein a loose source routing (LSR) field of the outer header identifies a recipient address;

updating, by the network node, the outer header of the packet to obtain an updated packet with an updated outer header,

wherein the source address of the updated outer header is updated to the tunnel endpoint associated with the network node, and the destination address of the updated outer header is updated to a tunnel endpoint associated with a receiving network node; and

routing, by the network node, the updated packet according to the updated outer header.

2. The method of claim 1 , further comprising:

determining a next hop network node for the packet to reach a recipient address by referencing a routing table of an intermediate network node based on the recipient address identified by an option field of the outer header; and

wherein updating the outer header of the packet comprises:

updating the outer header of the packet based on determining the next hop network node.

3. The method of claim 1 , wherein the packet includes an an inner header that is an IP address.

4. The method of claim 1 , wherein the packet includes an inner header that is encapsulated by a Generic Routing Encapsulation (GRE) header and the GRE header is encapsulated by an Encapsulating Security Payload (ESP) header that provides encryption.

5. The method of claim 1 , wherein receiving the packet comprises:

receiving the packet from the transmitting network node,

the transmitting network node having encapsulated the packet according to a Generating Routing Encapsulation (GRE) tunneling protocol based on determining that a destination for the packet was reachable via a GRE tunnel.

6. The method of claim 1 , wherein the packet is encrypted, and

wherein the method further comprises:

decrypting the packet to identify a recipient address.

7. A network node, comprising:

one or more memories; and

one or more processors, communicatively coupled to the one or more memories, to:

receive a packet that includes an outer header,

wherein a source address of the outer header identifies a tunnel endpoint associated with a transmitting network node, and a destination address of the outer header identifies a tunnel endpoint associated with the network node, and

wherein a loose source routing (LSR) field of the outer header identifies a recipient address;

update the outer header of the packet to obtain an updated packet with an updated outer header,

wherein the source address of the updated outer header is updated to the tunnel endpoint associated with the network node, and the destination address of the updated outer header is updated to a tunnel endpoint associated with a receiving network node; and

route the updated packet according to the updated outer header.

8. The network node of claim 7 , wherein the one or more processors are further to:

determine a next hop network node for the packet to reach a recipient address by referencing a routing table of an intermediate network node based on the recipient address identified by an option field of the outer header; and

wherein the one or more processors, when updating the outer header of the packet, are to:

update the outer header of the packet based on determining the next hop network node.

9. The network node of claim 7 , wherein the network node, the transmitting network node, and the receiving network node are associated with a virtual private network (VPN).

10. The network node of claim 7 , wherein the outer header is an IP address.

11. The network node of claim 7 , wherein the one or more processors, when receiving the packet, are to:

receive the packet from the transmitting network node,

the transmitting network node having encapsulated the packet according to a Generating Routing Encapsulation (GRE) tunneling protocol based on determining that a destination for the packet was reachable via a GRE tunnel.

12. The network node of claim 7 , wherein the packet is encrypted, and

wherein the one or more processors are further to:

decrypt the packet to identify a recipient address.

13. A non-transitory computer-readable medium storing instructions, the instructions comprising:

one or more instructions that, when executed by one or more processors, cause the one or more processors to:

receive a packet that includes an outer header,

wherein a source address of the outer header identifies a tunnel endpoint associated with a transmitting network node, and a destination address of the outer header identifies a tunnel endpoint associated with the network node, and

wherein a loose source routing (LSR) field of the outer header identifies a recipient address;

update the outer header of the packet to obtain an updated packet with an updated outer header,

wherein the source address of the updated outer header is updated to the tunnel endpoint associated with the network node, and the destination address of the updated outer header is updated to a tunnel endpoint associated with a receiving network node; and

route the updated packet according to the updated outer header.

14. The non-transitory computer-readable medium of claim 13 , wherein the one or more instructions, that further cause the one or more processors to:

determine a next hop network node for the packet to reach a recipient address by referencing a routing table of an intermediate network node based on the recipient address identified by an option field of the outer header; and

wherein the one or more instructions, that cause the one or more processors to update the outer header of the packet are to:

update the outer header of the packet based on determining the next hop network node.

15. The non-transitory computer-readable medium of claim 13 , wherein the network node, the transmitting network node, and the receiving network node are associated with a virtual private network.

16. The non-transitory computer-readable medium of claim 13 , wherein the packet includes an inner header that is encapsulated by a Generic Routing Encapsulation (GRE) header and the GRE header is encapsulated by an Encapsulating Security Payload (ESP) header that provides encryption.

17. The non-transitory computer-readable medium of claim 13 , wherein the one or more instructions, that further cause the one or more processors to:

receive the packet from the transmitting network node,

the transmitting network node having encapsulated the packet according to a Generating Routing Encapsulation (GRE) tunneling protocol based on determining that a destination for the packet was reachable via a GRE tunnel.

18. The method of claim 1 , wherein the packet includes an inner header and the outer header,

wherein a source address of the inner header identifies a sender address, and a destination address of the inner header identifies a recipient address.

19. The network node of claim 7 , wherein the packet includes an inner header and the outer header,

wherein a source address of the inner header identifies a sender address, and a destination address of the inner header identifies a recipient address.

20. The non-transitory computer-readable medium of claim 13 , wherein the packet that includes an inner header and the outer header,

wherein a source address of the inner header identifies a sender address, and a destination address of the inner header identifies a recipient address.