feat(src): add support for OpenBSD

- add OpenBSD-specifics to route socket handler
- add rc.d daemon file
- update README

Tested on riscv64 with OpenBSD 7.4

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+- Support for OpenBSD (tested on riscv64 with OpenBSD 7.4)
 - Configuration files for firewalld (#186). Thanks to Ondrej Holy.
 - Show device type and allow filtering in API's `list` command (#189). Thanks to Ondrej Holy.
 - Add option `--metadata-timeout` to set the timeout for the HTTP-based metadata exchange (closes #83)

README.md

@@ -37,8 +37,8 @@ Samba at some time in the future.
 
 # Requirements
 
-wsdd requires Python 3.7 and later only. It runs on Linux, FreeBSD and MacOS. Other Unixes, such
-as OpenBSD or NetBSD, might work as well but were not tested.
+wsdd requires Python 3.7 and later only. It runs on Linux, FreeBSD, OpenBSD and MacOS. 
+Other Unixes, such as NetBSD, might work as well but were not tested.
 
 Although Samba is not strictly required by wsdd itself, it makes sense to run
 wsdd only on hosts with a running Samba daemon. Note that the OpenRC/Gentoo

etc/rc.d/wsdd.openbsd

@@ -0,0 +1,25 @@
+#!/bin/ksh
+
+workgroup=$(/usr/local/bin/testparm -s --parameter-name workgroup 2>/dev/null)
+samba_config_file="/etc/samba/smb.conf"
+
+if [ -z ${workgroup} ] && [ -r "${samba_config_file}" ]; then
+	workgroup=$(grep -i -E '^[[:space:]]*workgroup' "${samba_config_file}" | cut -f2 -d= | tr -d '[:blank:]')
+fi
+
+if [ -n "$workgroup" ]; then
+	daemon_flags="-w ${workgroup}"
+fi
+
+daemon="python3 /usr/local/bin/wsdd"
+
+# create user with
+# doas useradd -g =uid -c "WSD Daemon" -L daemon -s /sbin/nologin -d /var/empty -r 100..999 _wsdd
+daemon_user="_wsdd"
+
+. /etc/rc.d/rc.subr
+
+rc_bg="YES"
+rc_reload="NO"
+
+rc_cmd $1

src/wsdd.py

@@ -287,8 +287,10 @@ def init_v4(self) -> None:
         self.uc_send_socket.bind((self.address.address_str, WSD_UDP_PORT))
 
         self.mc_send_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, mreq)
-        self.mc_send_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 0)
-        self.mc_send_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, args.hoplimit)
+        # OpenBSD requires the optlen to be sizeof(char) for LOOP and TTL options
+        # (see also https://github.com/python/cpython/issues/67316)
+        self.mc_send_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, struct.pack('B', 0))
+        self.mc_send_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, struct.pack('B', args.hoplimit))
 
         self.listen_address = (self.address.address_str, WSD_HTTP_PORT)
 
@@ -1580,7 +1582,7 @@ def cleanup(self) -> None:
 
 # from sys/net/if.h
 IFF_LOOPBACK: int = 0x8
-IFF_MULTICAST: int = 0x800
+IFF_MULTICAST: int = 0x800 if platform.system() != 'OpenBSD' else 0x8000
 
 # sys/netinet6/in6_var.h
 IN6_IFF_TENTATIVE: int = 0x02
@@ -1595,29 +1597,39 @@ class RouteSocketAddressMonitor(NetworkAddressMonitor):
     Implementation of the AddressMonitor for FreeBSD and Darwin using route sockets
     """
 
-    # Common definition for beginning part of if(m?a)?_msghdr structs (see net/if.h).
-    IF_COMMON_HDR_DEF: str = '@HBBii'
+    # Common definition for beginning part of if(m?a)?_msghdr structs (see net/if.h/man 4 route).
+    IF_COMMON_HDR_DEF = '@HBBii' if platform.system() != 'OpenBSD' else'@HBBHHHBBiii'
+
+    # from net/if.h
     RTM_NEWADDR: int = 0xC
     RTM_DELADDR: int = 0xD
+    # not tested for OpenBSD
     RTM_IFINFO: int = 0xE
 
+    # from route.h (value equals for FreeBSD, Darwin and OpenBSD)
+    RTM_VERSION: int = 0x5
+
     # from net/if.h (struct ifa_msghdr)
-    IFA_MSGHDR_DEF: str = IF_COMMON_HDR_DEF + 'hi'
+    IFA_MSGHDR_DEF: str = IF_COMMON_HDR_DEF + ('hi' if platform.system() != 'OpenBSD' else '')
     IFA_MSGHDR_SIZE: int = struct.calcsize(IFA_MSGHDR_DEF)
 
-    IF_MSGHDR_DEF_BASE: str = IF_COMMON_HDR_DEF + 'h'
     # The struct package does not allow to specify those, thus we hard code them as chars (x4).
-    IF_DATA_DEFS: Dict[str, str] = {
+    IF_MSG_DEFS: Dict[str, str] = {
         # if_data in if_msghdr is prepended with an u_short _ifm_spare1, thus the 'H' a the beginning)
-        'FreeBSD': 'H6c2c8c8c104c8c16c',
+        'FreeBSD': 'hH6c2c8c8c104c8c16c',
         # There are 8 bytes and 22 uint32_t in the if_data struct (22 x 4 Bytes + 8 = 96 Bytes)
         # It is also aligned on 4-byte boundary necessitating 2 bytes padding inside if_msghdr
-        'Darwin': '2c8c22I'
+        'Darwin': 'h2c8c22I',
+        # struct if_data from /src/sys/net/if.h for if_msghdr
+        #  (includes struct timeval which is a int64 + long
+        'OpenBSD': '4c3I13Q1Iql'
     }
 
     socket: socket.socket
     intf_blacklist: List[str]
 
+    is_openbsd: bool = False
+
     def __init__(self, aio_loop: asyncio.AbstractEventLoop) -> None:
         super().__init__(aio_loop)
         self.intf_blacklist = []
@@ -1627,7 +1639,8 @@ def __init__(self, aio_loop: asyncio.AbstractEventLoop) -> None:
         self.socket = socket.socket(socket.AF_ROUTE, socket.SOCK_RAW, socket.AF_UNSPEC)
         self.aio_loop.add_reader(self.socket.fileno(), self.handle_change)
 
-        self.IF_MSGHDR_SIZE = struct.calcsize(self.IF_MSGHDR_DEF_BASE + self.IF_DATA_DEFS[platform.system()])
+        self.IF_MSGHDR_SIZE = struct.calcsize(self.IF_COMMON_HDR_DEF + self.IF_MSG_DEFS[platform.system()])
+        self.is_openbsd = platform.system() == 'OpenBSD'
 
     def do_enumerate(self) -> None:
         super().do_enumerate()
@@ -1661,9 +1674,20 @@ def parse_route_socket_response(self, buf: bytes, keep_intf: bool) -> None:
         intf_flags = 0
         while offset < len(buf):
             # unpack route message response
-            rtm_len, _, rtm_type, addr_mask, flags = struct.unpack_from(self.IF_COMMON_HDR_DEF, buf, offset)
+            if not self.is_openbsd:
+                rtm_len, rtm_version, rtm_type, addr_mask, flags = struct.unpack_from(
+                        self.IF_COMMON_HDR_DEF, buf, offset)
+            else:
+                rtm_len, rtm_version, rtm_type, ifa_hdr_len, _, _, _, _, addr_mask, flags, _ = struct.unpack_from(
+                        self.IF_COMMON_HDR_DEF, buf, offset)
+
+            # exit condition for OpenBSD where always the complete buffer (ie 4096 bytes) is returned
+            if rtm_len == 0:
+                break;
 
-            if rtm_type not in [self.RTM_NEWADDR, self.RTM_DELADDR, self.RTM_IFINFO]:
+            # skip over non-understood packets and versions
+            if (rtm_type not in [self.RTM_NEWADDR, self.RTM_DELADDR, self.RTM_IFINFO]) or (
+                    rtm_version != self.RTM_VERSION):
                 offset += rtm_len
                 continue
 
@@ -1946,7 +1970,7 @@ def drop_privileges(uid: int, gid: int) -> bool:
 def create_address_monitor(system: str, aio_loop: asyncio.AbstractEventLoop) -> NetworkAddressMonitor:
     if system == 'Linux':
         return NetlinkAddressMonitor(aio_loop)
-    elif system in ['FreeBSD', 'Darwin']:
+    elif system in ['FreeBSD', 'Darwin', 'OpenBSD']:
         return RouteSocketAddressMonitor(aio_loop)
     else:
         raise NotImplementedError('unsupported OS: ' + system)

test/routesocket_monitor.py

@@ -6,6 +6,7 @@
 import socket
 import struct
 import ctypes.util
+import platform
 
 # from sys/net/route.h
 RTM_NEWADDR = 0xC
@@ -20,7 +21,7 @@
 
 # from sys/net/if.h
 IFF_LOOPBACK = 0x8
-IFF_MULTICAST = 0x800
+IFF_MULTICAST = 0x800 if platform.system() != 'OpenBSD' else 0x8000
 
 SA_ALIGNTO = ctypes.sizeof(ctypes.c_long)
 
@@ -34,18 +35,26 @@ def parse_route_socket_response(buf, keep_link):
     link = None
     print(len(buf))
     while offset < len(buf):
-        # mask(addrs) has same offset in if_msghdr and ifs_msghdr
-        rtm_len, _, rtm_type, addr_mask, flags = struct.unpack_from(
-            '@HBBii', buf, offset)
+        if platform.system() != 'OpenBSD':
+            # mask(addrs) has same offset in if_msghdr and ifs_msghdr
+            rtm_len, _, rtm_type, addr_mask, flags = struct.unpack_from(
+                '@HBBii', buf, offset)
+        else:
+            rtm_len, _, rtm_type, hdr_len, if_idx, ignore_table, ignore_prio, ignore_mlps, addr_mask, flags, change_mask = struct.unpack_from(
+                '@HBBHHHBBiii', buf, offset)
 
         msg_type = ''
         if rtm_type not in [RTM_NEWADDR, RTM_DELADDR, RTM_IFINFO]:
             offset += rtm_len
             continue
 
         # those offset may unfortunately be architecture dependent
-        # (152 is FreeBSD-specific)
-        sa_offset = offset + ((16 + 152) if rtm_type == RTM_IFINFO else 20)
+        if platform.system() != 'OpenBSD':
+            # (152 is FreeBSD-specific)
+            sa_offset = offset + ((16 + 152) if rtm_type == RTM_IFINFO else 20)
+        else:
+            # RTM_IFINFO not tested, offset might be wrong
+            sa_offset = offset + ((16 + 152) if rtm_type == RTM_IFINFO else 24)
 
         if rtm_type in [RTM_NEWADDR, RTM_IFINFO]:
             msg_type = 'NEW'