diff --git a/stubs/psutil/psutil/_pssunos.pyi b/stubs/psutil/psutil/_pssunos.pyi
index 3080720cca60..2676147f64bb 100644
--- a/stubs/psutil/psutil/_pssunos.pyi
+++ b/stubs/psutil/psutil/_pssunos.pyi
@@ -1,129 +1,151 @@
-from _typeshed import Incomplete
-from typing import NamedTuple
-
-from psutil._common import (
-    AF_INET6 as AF_INET6,
-    AccessDenied as AccessDenied,
-    NoSuchProcess as NoSuchProcess,
-    ZombieProcess as ZombieProcess,
-    debug as debug,
-    get_procfs_path as get_procfs_path,
-    isfile_strict as isfile_strict,
-    memoize_when_activated as memoize_when_activated,
-    sockfam_to_enum as sockfam_to_enum,
-    socktype_to_enum as socktype_to_enum,
-    usage_percent as usage_percent,
-)
-
-__extra__all__: Incomplete
-PAGE_SIZE: Incomplete
-AF_LINK: Incomplete
-IS_64_BIT: Incomplete
-CONN_IDLE: str
-CONN_BOUND: str
-PROC_STATUSES: Incomplete
-TCP_STATUSES: Incomplete
-proc_info_map: Incomplete
-
-class scputimes(NamedTuple):
-    user: Incomplete
-    system: Incomplete
-    idle: Incomplete
-    iowait: Incomplete
-
-class pcputimes(NamedTuple):
-    user: Incomplete
-    system: Incomplete
-    children_user: Incomplete
-    children_system: Incomplete
-
-class svmem(NamedTuple):
-    total: Incomplete
-    available: Incomplete
-    percent: Incomplete
-    used: Incomplete
-    free: Incomplete
-
-class pmem(NamedTuple):
-    rss: Incomplete
-    vms: Incomplete
-
-pfullmem = pmem
-
-class pmmap_grouped(NamedTuple):
-    path: Incomplete
-    rss: Incomplete
-    anonymous: Incomplete
-    locked: Incomplete
-
-pmmap_ext: Incomplete
-
-def virtual_memory(): ...
-def swap_memory(): ...
-def cpu_times(): ...
-def per_cpu_times(): ...
-def cpu_count_logical(): ...
-def cpu_count_cores(): ...
-def cpu_stats(): ...
-
-disk_io_counters: Incomplete
-disk_usage: Incomplete
-
-def disk_partitions(all: bool = ...): ...
-
-net_io_counters: Incomplete
-net_if_addrs: Incomplete
-
-def net_connections(kind, _pid: int = ...): ...
-def net_if_stats(): ...
-def boot_time(): ...
-def users(): ...
-def pids(): ...
-def pid_exists(pid): ...
-def wrap_exceptions(fun): ...
-
-class Process:
-    pid: Incomplete
-    def __init__(self, pid) -> None: ...
-    def oneshot_enter(self) -> None: ...
-    def oneshot_exit(self) -> None: ...
-    def name(self): ...
-    def exe(self): ...
-    def cmdline(self): ...
-    def environ(self): ...
-    def create_time(self): ...
-    def num_threads(self): ...
-    def nice_get(self): ...
-    def nice_set(self, value): ...
-    def ppid(self): ...
-    def uids(self): ...
-    def gids(self): ...
-    def cpu_times(self): ...
-    def cpu_num(self): ...
-    def terminal(self): ...
-    def cwd(self): ...
-    def memory_info(self): ...
-    memory_full_info: Incomplete
-    def status(self): ...
-    def threads(self): ...
-    def open_files(self): ...
-    def net_connections(self, kind: str = ...): ...
-
-    class nt_mmap_grouped(NamedTuple):
+import sys
+
+# sys.platform.startswith(("sunos", "solaris")):
+if sys.platform != "linux" and sys.platform != "win32" and sys.platform != "darwin":
+    from _typeshed import Incomplete
+    from collections.abc import Callable
+    from typing import Final, Literal, NamedTuple, TypeVar, overload
+    from typing_extensions import ParamSpec
+
+    from psutil._common import (
+        AF_INET6 as AF_INET6,
+        ENCODING as ENCODING,
+        AccessDenied as AccessDenied,
+        NoSuchProcess as NoSuchProcess,
+        ZombieProcess as ZombieProcess,
+        debug as debug,
+        get_procfs_path as get_procfs_path,
+        isfile_strict as isfile_strict,
+        memoize_when_activated as memoize_when_activated,
+        sockfam_to_enum as sockfam_to_enum,
+        socktype_to_enum as socktype_to_enum,
+        usage_percent as usage_percent,
+    )
+
+    from . import _common, _psposix, _psutil_sunos
+
+    _P = ParamSpec("_P")
+    _R = TypeVar("_R")
+
+    __extra__all__: Final[list[str]]
+    PAGE_SIZE: Final[int]
+    AF_LINK: Final[int]
+    IS_64_BIT: Final[bool]
+    CONN_IDLE: Final = "IDLE"
+    CONN_BOUND: Final = "BOUND"
+    PROC_STATUSES: Final[dict[int, str]]
+    TCP_STATUSES: Final[dict[int, str]]
+    proc_info_map: Final[dict[str, int]]
+
+    class scputimes(NamedTuple):
+        user: float
+        system: float
+        idle: float
+        iowait: float
+
+    class pcputimes(NamedTuple):
+        user: float
+        system: float
+        children_user: float
+        children_system: float
+
+    class svmem(NamedTuple):
+        total: int
+        available: int
+        percent: float
+        used: int
+        free: int
+
+    class pmem(NamedTuple):
+        rss: int
+        vms: int
+
+    pfullmem = pmem
+
+    class pmmap_grouped(NamedTuple):
         path: Incomplete
         rss: Incomplete
-        anon: Incomplete
+        anonymous: Incomplete
         locked: Incomplete
 
-    class nt_mmap_ext(NamedTuple):
+    class pmmap_ext(NamedTuple):
         addr: Incomplete
         perms: Incomplete
         path: Incomplete
         rss: Incomplete
-        anon: Incomplete
+        anonymous: Incomplete
         locked: Incomplete
 
-    def memory_maps(self): ...
-    def num_fds(self): ...
-    def num_ctx_switches(self): ...
-    def wait(self, timeout: Incomplete | None = ...): ...
+    def virtual_memory() -> svmem: ...
+    def swap_memory() -> _common.sswap: ...
+    def cpu_times() -> scputimes: ...
+    def per_cpu_times() -> list[scputimes]: ...
+    def cpu_count_logical() -> int | None: ...
+    def cpu_count_cores() -> int | None: ...
+    def cpu_stats() -> _common.scpustats: ...
+
+    disk_io_counters = _psutil_sunos.disk_io_counters
+    disk_usage = _psposix.disk_usage
+
+    def disk_partitions(all: bool = False) -> list[_common.sdiskpart]: ...
+
+    net_io_counters = _psutil_sunos.net_io_counters
+    net_if_addrs = _psutil_sunos.net_if_addrs
+
+    @overload
+    def net_connections(kind: str, _pid: Literal[-1] = -1) -> list[_common.sconn]: ...
+    @overload
+    def net_connections(kind: str, _pid: int = -1) -> list[_common.pconn]: ...
+    def net_if_stats() -> dict[str, _common.snicstats]: ...
+    def boot_time() -> float: ...
+    def users() -> list[_common.suser]: ...
+    def pids() -> list[int]: ...
+    def pid_exists(pid: int) -> bool: ...
+    def wrap_exceptions(fun: Callable[_P, _R]) -> Callable[_P, _R]: ...
+
+    class Process:
+        __slots__ = ["_cache", "_name", "_ppid", "_procfs_path", "pid"]
+        pid: int
+        def __init__(self, pid: int) -> None: ...
+        def oneshot_enter(self) -> None: ...
+        def oneshot_exit(self) -> None: ...
+        def name(self) -> str: ...
+        def exe(self) -> str: ...
+        def cmdline(self) -> list[str] | None: ...
+        def environ(self) -> dict[str, str]: ...
+        def create_time(self) -> float: ...
+        def num_threads(self) -> int: ...
+        def nice_get(self) -> int: ...
+        def nice_set(self, value: int) -> None: ...
+        def ppid(self) -> int: ...
+        def uids(self) -> _common.puids: ...
+        def gids(self) -> _common.puids: ...
+        def cpu_times(self) -> _common.pcputimes: ...
+        def cpu_num(self) -> int: ...
+        def terminal(self) -> str | None: ...
+        def cwd(self) -> str: ...
+        def memory_info(self) -> pmem: ...
+        memory_full_info = memory_info
+        def status(self) -> str: ...
+        def threads(self) -> list[_common.pthread]: ...
+        def open_files(self) -> list[_common.popenfile]: ...
+        def net_connections(self, kind: str = "inet") -> list[_common.pconn]: ...
+
+        class nt_mmap_grouped(NamedTuple):
+            path: Incomplete
+            rss: Incomplete
+            anon: Incomplete
+            locked: Incomplete
+
+        class nt_mmap_ext(NamedTuple):
+            addr: Incomplete
+            perms: Incomplete
+            path: Incomplete
+            rss: Incomplete
+            anon: Incomplete
+            locked: Incomplete
+
+        def memory_maps(self) -> list[tuple[str, str, str, int, int, int]]: ...
+        def num_fds(self) -> int: ...
+        def num_ctx_switches(self) -> _common.pctxsw: ...
+        def wait(self, timeout: float | None = None): ...
diff --git a/stubs/psutil/psutil/_psutil_osx.pyi b/stubs/psutil/psutil/_psutil_osx.pyi
index 712d0fa93401..e6bef26354da 100644
--- a/stubs/psutil/psutil/_psutil_osx.pyi
+++ b/stubs/psutil/psutil/_psutil_osx.pyi
@@ -8,8 +8,7 @@ if sys.platform == "darwin":
 
     _T = TypeVar("_T")
 
-    # TODO: Add POSIX constants and check their aviability (see psutil_posix_add_constants)
-    AF_LINK: Incomplete
+    AF_LINK: Final = 18
 
     def getpagesize() -> int: ...
     def net_if_addrs(): ...
diff --git a/stubs/psutil/psutil/_psutil_sunos.pyi b/stubs/psutil/psutil/_psutil_sunos.pyi
index 9539ebed9f37..b98853632d27 100644
--- a/stubs/psutil/psutil/_psutil_sunos.pyi
+++ b/stubs/psutil/psutil/_psutil_sunos.pyi
@@ -1,59 +1,64 @@
-from _typeshed import Incomplete
+import sys
 
-# TODO: Add POSIX constants and check their aviability (see psutil_posix_add_constants)
-AF_LINK: Incomplete
+# sys.platform.startswith(("sunos", "solaris")):
+if sys.platform != "linux" and sys.platform != "win32" and sys.platform != "darwin":
+    from _typeshed import Incomplete
+    from typing import Final
 
-def getpagesize() -> int: ...
-def net_if_addrs(): ...
-def net_if_flags(nic_name: str, /) -> list[str]: ...
-def net_if_is_running(nic_name: str, /) -> bool: ...
-def net_if_mtu(nic_name: str, /) -> int: ...
-def proc_priority_get(pid: int, /) -> int: ...
-def proc_priority_set(pid: int, priority: int, /) -> None: ...
-def users() -> list[tuple[Incomplete, ...]]: ...
+    AF_LINK: Final[int]
 
-version: Incomplete
-SSLEEP: Incomplete
-SRUN: Incomplete
-SZOMB: Incomplete
-SSTOP: Incomplete
-SIDL: Incomplete
-SONPROC: Incomplete
-SWAIT: Incomplete
-PRNODEV: Incomplete
-TCPS_CLOSED: Incomplete
-TCPS_CLOSING: Incomplete
-TCPS_CLOSE_WAIT: Incomplete
-TCPS_LISTEN: Incomplete
-TCPS_ESTABLISHED: Incomplete
-TCPS_SYN_SENT: Incomplete
-TCPS_SYN_RCVD: Incomplete
-TCPS_FIN_WAIT_1: Incomplete
-TCPS_FIN_WAIT_2: Incomplete
-TCPS_LAST_ACK: Incomplete
-TCPS_TIME_WAIT: Incomplete
-TCPS_IDLE: Incomplete
-TCPS_BOUND: Incomplete
-PSUTIL_CONN_NONE: Incomplete
+    def getpagesize() -> int: ...
+    def net_if_addrs(): ...
+    def net_if_flags(nic_name: str, /) -> list[str]: ...
+    def net_if_is_running(nic_name: str, /) -> bool: ...
+    def net_if_mtu(nic_name: str, /) -> int: ...
+    def proc_priority_get(pid: int, /) -> int: ...
+    def proc_priority_set(pid: int, priority: int, /) -> None: ...
+    def users() -> list[tuple[Incomplete, ...]]: ...
 
-def proc_basic_info(pid: int, procfs_path: str, /) -> tuple[Incomplete, ...]: ...
-def proc_cpu_num(pid: int, procfs_path: str, /): ...
-def proc_cpu_times(pid: int, procfs_path: str, /): ...
-def proc_cred(pid: int, procfs_path: str, /): ...
-def proc_environ(pid: int, procfs_path: str, /): ...
-def proc_memory_maps(pid: int, procfs_path: str, /): ...
-def proc_name_and_args(pid: int, procfs_path: str, /): ...
-def proc_num_ctx_switches(pid: int, procfs_path: str, /): ...
-def query_process_thread(pid: int, tid: int, procfs_path: str, /): ...
-def boot_time(): ...
-def cpu_count_cores(): ...
-def cpu_stats(): ...
-def disk_io_counters(): ...
-def disk_partitions(): ...
-def net_connections(pid: int, /): ...
-def net_if_stats(): ...
-def net_io_counters(): ...
-def per_cpu_times(): ...
-def swap_mem(): ...
-def check_pid_range(pid: int, /): ...
-def set_debug(value: bool, /) -> None: ...
+    version: Final[int]
+    # They could be different between different versions of SunOS/Solaris:
+    SSLEEP: Final[int]
+    SRUN: Final[int]
+    SZOMB: Final[int]
+    SSTOP: Final[int]
+    SIDL: Final[int]
+    SONPROC: Final[int]
+    SWAIT: Final[int]
+    PRNODEV: Final[int]
+    TCPS_CLOSED: Final[int]
+    TCPS_CLOSING: Final[int]
+    TCPS_CLOSE_WAIT: Final[int]
+    TCPS_LISTEN: Final[int]
+    TCPS_ESTABLISHED: Final[int]
+    TCPS_SYN_SENT: Final[int]
+    TCPS_SYN_RCVD: Final[int]
+    TCPS_FIN_WAIT_1: Final[int]
+    TCPS_FIN_WAIT_2: Final[int]
+    TCPS_LAST_ACK: Final[int]
+    TCPS_TIME_WAIT: Final[int]
+    TCPS_IDLE: Final[int]
+    TCPS_BOUND: Final[int]
+    PSUTIL_CONN_NONE: Final = 128
+
+    def proc_basic_info(pid: int, procfs_path: str, /) -> tuple[int, int, int, float, int, int, int, int, int, int, int, int]: ...
+    def proc_cpu_num(pid: int, procfs_path: str, /) -> int: ...
+    def proc_cpu_times(pid: int, procfs_path: str, /) -> tuple[float, float, float, float]: ...
+    def proc_cred(pid: int, procfs_path: str, /) -> tuple[int, int, int, int, int, int]: ...
+    def proc_environ(pid: int, procfs_path: str, /) -> dict[str, str]: ...
+    def proc_memory_maps(pid: int, procfs_path: str, /) -> list[tuple[int, int, str, str, int, int, int]]: ...
+    def proc_name_and_args(pid: int, procfs_path: str, /) -> tuple[str, list[str] | None]: ...
+    def proc_num_ctx_switches(pid: int, procfs_path: str, /) -> tuple[int, int]: ...
+    def query_process_thread(pid: int, tid: int, procfs_path: str, /) -> tuple[float, float]: ...
+    def boot_time() -> float: ...
+    def cpu_count_cores() -> int | None: ...
+    def cpu_stats() -> tuple[int, int, int, int]: ...
+    def disk_io_counters() -> dict[str, tuple[int, int, int, int, int, int]]: ...
+    def disk_partitions() -> list[tuple[str, str, str, str]]: ...
+    def net_connections(pid: int, /) -> list[tuple[int, int, int, tuple[str, int], tuple[str, int] | tuple[()], int, int]]: ...
+    def net_if_stats() -> dict[str, tuple[bool, int, int, int]]: ...
+    def net_io_counters() -> dict[str, tuple[int, int, int, int, int, int, int, int]]: ...
+    def per_cpu_times() -> list[tuple[float, float, float, float]]: ...
+    def swap_mem() -> tuple[int, int]: ...
+    def check_pid_range(pid: int, /) -> None: ...
+    def set_debug(value: bool, /) -> None: ...