Want vsock packet dtrace probes

[papertigers]

We want the ability to trace packet flows from guest<-->host.

❯ pfexec dtrace -Zqn 'propolis*:::vsock_pkt_* {printf("%s\n\n", json(copyinstr(arg0), "ok"));}'  | jq
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 0,
  "socket_type": "Stream",
  "op": "Request",
  "flags": "",
  "buf_alloc": 262144,
  "fwd_cnt": 0
}
{
  "src_cid": 2,
  "dst_cid": 16,
  "src_port": 2222,
  "dst_port": 3308370434,
  "len": 0,
  "socket_type": "Stream",
  "op": "Response",
  "flags": "",
  "buf_alloc": 131072,
  "fwd_cnt": 0
}
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 22,
  "socket_type": "Stream",
  "op": "ReadWrite",
  "flags": "",
  "buf_alloc": 262144,
  "fwd_cnt": 0
}
{
  "src_cid": 2,
  "dst_cid": 16,
  "src_port": 2222,
  "dst_port": 3308370434,
  "len": 22,
  "socket_type": "Stream",
  "op": "ReadWrite",
  "flags": "",
  "buf_alloc": 131072,
  "fwd_cnt": 22
}
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 0,
  "socket_type": "Stream",
  "op": "CreditUpdate",
  "flags": "",
  "buf_alloc": 262144,
  "fwd_cnt": 22
}
..... snip ......
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 96,
  "socket_type": "Stream",
  "op": "ReadWrite",
  "flags": "",
  "buf_alloc": 262144,
  "fwd_cnt": 5278
}
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 0,
  "socket_type": "Stream",
  "op": "Shutdown",
  "flags": "VIRTIO_VSOCK_SHUTDOWN_F_SEND",
  "buf_alloc": 262144,
  "fwd_cnt": 5278
}
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 0,
  "socket_type": "Stream",
  "op": "Shutdown",
  "flags": "VIRTIO_VSOCK_SHUTDOWN_F_RECEIVE | VIRTIO_VSOCK_SHUTDOWN_F_SEND",
  "buf_alloc": 262144,
  "fwd_cnt": 5278
}
{
  "src_cid": 2,
  "dst_cid": 16,
  "src_port": 2222,
  "dst_port": 3308370434,
  "len": 0,
  "socket_type": "Stream",
  "op": "Reset",
  "flags": "",
  "buf_alloc": 131072,
  "fwd_cnt": 0
}
{
  "src_cid": 16,
  "dst_cid": 2,
  "src_port": 3308370434,
  "dst_port": 2222,
  "len": 0,
  "socket_type": "Stream",
  "op": "Reset",
  "flags": "",
  "buf_alloc": 262144,
  "fwd_cnt": 5278
}

[iximeow]

easy signoff :) the json stuff in dtrace is neat!