Add new TCP-BPF callback that is called on listen(2) right after socket transition to TCP_LISTEN state. It fills the gap for listening sockets in TCP-BPF. For example BPF program can set BPF_SOCK_OPS_STATE_CB_FLAG when socket becomes listening and track later transition from TCP_LISTEN to TCP_CLOSE with BPF_SOCK_OPS_STATE_CB callback. Before there was no way to do it with TCP-BPF and other options were much harder to work with. E.g. socket state tracking can be done with tracepoints (either raw or regular) but they can't be attached to cgroup and their lifetime has to be managed separately.
Showing the changes to include/uapi/linux (1 of 2 files). Show all
Unified · Split
| @@ -2555,6 +2555,9 @@ enum { · 2554 unmodified lines | |||
| 2555 | * Arg1: old_state | 2555 | * Arg1: old_state |
| 2556 | * Arg2: new_state | 2556 | * Arg2: new_state |
| 2557 | */ | 2557 | */ |
| 2558 | BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after | ||
| 2559 | * socket transition to LISTEN state. | ||
| 2560 | */ | ||
| 2558 | }; | 2561 | }; |
| 2559 | 2562 | ||
| 2560 | /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect | 2563 | /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect |