[Question] Confirm whether the handshake has been re-handshake when establishing a connection with sess_resume?

[nmgwddj]

I have currently deployed more than 2 servers to receive QUIC connections. When using lsquic, the sess_resume information of the previous connection establishment will be saved, and this information will be carried when establishing the next connection. Carrying sess_resume on the same server indeed works well. Through the on_hsk_done callback, it can be judged that the enumeration value is LSQ_HSK_RESUMED_OK. However, when I use the sess_resume saved after connecting to server A to connect to server B, the on_hsk_done callback still gives me LSQ_HSK_RESUMED_OK, but actually, by packet capturing, it can be seen that the process of re-handshake has been gone through.

I would like to know if there are any other ways besides on_hsk_done to confirm whether the handshake process has been re-performed when establishing a connection with sess_resume carried? The following is the brief information of the captured data packets.

First connection to server A:

1034	11:03:57.100687	10.242.18.254	1.95.20.108	QUIC	1242	Initial, DCID=caa9e1466294f783e1c909, SCID=4430921bc928488f, PKN: 0, CRYPTO, PADDING
1035	11:03:57.133592	1.95.20.108	10.242.18.254	QUIC	113	Retry, DCID=4430921bc928488f, SCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586
1036	11:03:57.134651	10.242.18.254	1.95.20.108	QUIC	1242	Initial, DCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586, SCID=4430921bc928488f, PKN: 1, CRYPTO, PADDING
1039	11:03:57.168744	1.95.20.108	10.242.18.254	QUIC	1242	Handshake, DCID=4430921bc928488f, SCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586
1040	11:03:57.168746	1.95.20.108	10.242.18.254	QUIC	238	Handshake, DCID=4430921bc928488f, SCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586
1041	11:03:57.174671	10.242.18.254	1.95.20.108	QUIC	1242	Handshake, DCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586, SCID=4430921bc928488f
1042	11:03:57.178261	10.242.18.254	1.95.20.108	QUIC	207	Protected Payload (KP0), DCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586
1043	11:03:57.179203	10.242.18.254	1.95.20.108	QUIC	519	Protected Payload (KP0), DCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586
1045	11:03:57.206319	1.95.20.108	10.242.18.254	QUIC	101	Handshake, DCID=4430921bc928488f, SCID=b994d7d18d0a6b4fba92fe43196285ed15bf4586

Second connection to server A with sess_resume carried:

101	11:04:36.755887	10.242.18.254	1.95.20.108	QUIC	1242	Initial, DCID=c45941e6d4a85e3234226aeee4, SCID=25c6808842591c87, PKN: 0, CRYPTO, PADDING
102	11:04:36.757273	10.242.18.254	1.95.20.108	QUIC	528	0-RTT, DCID=c45941e6d4a85e3234226aeee4, SCID=25c6808842591c87
103	11:04:36.786931	1.95.20.108	10.242.18.254	QUIC	115	Retry, DCID=25c6808842591c87, SCID=6ee32a87aa2da771859d49f83708b0bbcdadd46a
104	11:04:36.787493	1.95.20.108	10.242.18.254	QUIC	115	Retry, DCID=25c6808842591c87, SCID=6ee32a87aa2da771859d49f83708b0bbcdadd46a
105	11:04:36.787816	10.242.18.254	1.95.20.108	QUIC	1242	Initial, DCID=6ee32a87aa2da771859d49f83708b0bbcdadd46a, SCID=25c6808842591c87, PKN: 2, CRYPTO, PADDING
106	11:04:36.819401	1.95.20.108	10.242.18.254	QUIC	1242	Protected Payload (KP0), DCID=25c6808842591c87

Third connection to server B using the sess_resume returned by server A:

2860	11:06:56.573823	10.242.18.254	1.95.20.100	QUIC	1242	Initial, DCID=0b551c8a07b1ede303f4bb, SCID=22b6dec45a520b7e, PKN: 0, CRYPTO, PADDING
2861	11:06:56.574948	10.242.18.254	1.95.20.100	QUIC	526	0-RTT, DCID=0b551c8a07b1ede303f4bb, SCID=22b6dec45a520b7e
2864	11:06:56.606431	1.95.20.100	10.242.18.254	QUIC	113	Retry, DCID=22b6dec45a520b7e, SCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2865	11:06:56.606433	1.95.20.100	10.242.18.254	QUIC	113	Retry, DCID=22b6dec45a520b7e, SCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2866	11:06:56.607361	10.242.18.254	1.95.20.100	QUIC	1242	Initial, DCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af, SCID=22b6dec45a520b7e, PKN: 2, CRYPTO, PADDING
2877	11:06:56.641322	1.95.20.100	10.242.18.254	QUIC	1242	Handshake, DCID=22b6dec45a520b7e, SCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2878	11:06:56.641325	1.95.20.100	10.242.18.254	QUIC	238	Handshake, DCID=22b6dec45a520b7e, SCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2879	11:06:56.647084	10.242.18.254	1.95.20.100	QUIC	1242	Handshake, DCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af, SCID=22b6dec45a520b7e
2880	11:06:56.650220	10.242.18.254	1.95.20.100	QUIC	207	Protected Payload (KP0), DCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2881	11:06:56.650225	10.242.18.254	1.95.20.100	QUIC	519	Protected Payload (KP0), DCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af
2894	11:06:56.678164	1.95.20.100	10.242.18.254	QUIC	101	Handshake, DCID=22b6dec45a520b7e, SCID=c5bb1ff61eecc733bad2cf3786cfacb21eb090af