Cherusk Tech MeanderingsGist
Disseminating a complementary and viably a more modern alternative to the established ss utility shipped with the well-known iproute package.
How to attain ss2?
It's part of the pyroute2 package install routines, so please follow those upstream to allow me to reduce redundancy in this regard.
Example Run
ss2 is offering, amongst many output formats, machine readable dumps of the kernel socket statistics. For it's renowned merits, json was chosen as the foremost default dumping format.
Mission is to proffer to the user of it everything the kernel can actually export as context to sockets.
Currently, as it is in its infancy, so not all aspects provided by ss have been implemented yet.
# ss2 --help
usage: ss2 [-h] [-x] [-t] [-l] [-a] [-p] [-r]ss2 - socket statistics depictor meant as a complete and convenient surrogate
for iproute2/misc/ss2optional arguments:
-h, --help show this help message and exit
-x, --unix Display Unix domain sockets.
-t, --tcp Display TCP sockets.
-l, --listen Display listening sockets.
-a, --all Display all sockets.
-p, --process show socket holding context
-r, --resolve resolve host names in addition
On a recent kernel (4.17.19-200.fc28.x86_64), following schema could be expected for TCP flows:
# ss2 -t
{
"TCP": {
"flows": [
{
"src": "10.0.2.15",
"src_port": 43332,
"retrans": 0,
"dst": "172.25.136.144",
"cong_algo": "cubic",
"dst_port": 22,
"meminfo": {
"r": 0,
"t": 0,
"w": 0,
"f": 4096
},
"iface_idx": 0,
"inode": 45433,
"tcp_info": {
"delivery_rate": 5615384,
"retrans": 0,
"data_segs_in": 19,
"rto": 201.0,
"segs_in": 35,
"rtt": 0.943,
"retransmits": 0,
"bytes_received": 5349,
"last_ack_sent": 0,
"rcv_space": 29200,
"rcv_mss": 1420,
"max_pacing_rate": 18446744073709551615,
"ca_state": 0,
"min_rtt": 260,
"segs_out": 26,
"advmss": 1460,
"state": "established",
"last_ack_recv": 113749,
"snd_wscale": 0,
"pmtu": 1500,
"busy_time": 8000,
"bytes_acked": 5630,
"rcv_ssthresh": 49800,
"total_retrans": 0,
"last_data_recv": 113749,
"unacked": 0,
"fackets": 0,
"sndbuf_limited": 0,
"sacked": 0,
"reordering": 3,
"pacing_rate": 30944495,
"rttvar": 0.859,
"snd_cwnd": 10,
"last_data_sent": 113995,
"null": 0,
"rcv_wscale": 0,
"probes": 0,
"notsent_bytes": 0,
"data_segs_out": 15,
"snd_ssthresh": null,
"lost": 0,
"ato": 40.0,
"rwnd_limited": 0,
"rcv_rtt": 0.0,
"delivery_rate_app_limited": 1,
"snd_mss": 1460,
"opts": []
}
}
]
}
}