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-rw-r--r--lib/pure/nativesockets.nim903
1 files changed, 609 insertions, 294 deletions
diff --git a/lib/pure/nativesockets.nim b/lib/pure/nativesockets.nim
index 8a7780570..656c98a20 100644
--- a/lib/pure/nativesockets.nim
+++ b/lib/pure/nativesockets.nim
@@ -8,51 +8,66 @@
 #
 
 ## This module implements a low-level cross-platform sockets interface. Look
-## at the ``net`` module for the higher-level version.
+## at the `net` module for the higher-level version.
 
 # TODO: Clean up the exports a bit and everything else in general.
 
-import unsigned, os
+import std/[os, options]
+import std/private/since
+import std/strbasics
+
+when defined(nimPreviewSlimSystem):
+  import std/[assertions, syncio]
 
 when hostOS == "solaris":
   {.passl: "-lsocket -lnsl".}
 
-const useWinVersion = defined(Windows) or defined(nimdoc)
+const useWinVersion = defined(windows) or defined(nimdoc)
+const useNimNetLite = defined(nimNetLite) or defined(freertos) or defined(zephyr) or
+    defined(nuttx)
 
 when useWinVersion:
-  import winlean
+  import std/winlean
   export WSAEWOULDBLOCK, WSAECONNRESET, WSAECONNABORTED, WSAENETRESET,
+         WSANOTINITIALISED, WSAENOTSOCK, WSAEINPROGRESS, WSAEINTR,
          WSAEDISCON, ERROR_NETNAME_DELETED
 else:
-  import posix
+  import std/posix
   export fcntl, F_GETFL, O_NONBLOCK, F_SETFL, EAGAIN, EWOULDBLOCK, MSG_NOSIGNAL,
-    EINTR, EINPROGRESS, ECONNRESET, EPIPE, ENETRESET
-  export Sockaddr_storage
+    EINTR, EINPROGRESS, ECONNRESET, EPIPE, ENETRESET, EBADF
+  export Sockaddr_storage, Sockaddr_un, Sockaddr_un_path_length
 
 export SocketHandle, Sockaddr_in, Addrinfo, INADDR_ANY, SockAddr, SockLen,
-  Sockaddr_in6,
-  inet_ntoa, recv, `==`, connect, send, accept, recvfrom, sendto
+  Sockaddr_in6, Sockaddr_storage,
+  recv, `==`, connect, send, accept, recvfrom, sendto,
+  freeAddrInfo
+
+when not useNimNetLite:
+  export inet_ntoa
 
 export
   SO_ERROR,
   SOL_SOCKET,
   SOMAXCONN,
   SO_ACCEPTCONN, SO_BROADCAST, SO_DEBUG, SO_DONTROUTE,
-  SO_KEEPALIVE, SO_OOBINLINE, SO_REUSEADDR,
+  SO_KEEPALIVE, SO_OOBINLINE, SO_REUSEADDR, SO_REUSEPORT,
   MSG_PEEK
 
 when defined(macosx) and not defined(nimdoc):
-    export SO_NOSIGPIPE
+  export SO_NOSIGPIPE
 
 type
-  Port* = distinct uint16  ## port type
-
-  Domain* = enum    ## domain, which specifies the protocol family of the
-                    ## created socket. Other domains than those that are listed
-                    ## here are unsupported.
-    AF_UNIX,        ## for local socket (using a file). Unsupported on Windows.
-    AF_INET = 2,    ## for network protocol IPv4 or
-    AF_INET6 = 23   ## for network protocol IPv6.
+  Port* = distinct uint16 ## port type
+
+  Domain* = enum ## \
+    ## domain, which specifies the protocol family of the
+    ## created socket. Other domains than those that are listed
+    ## here are unsupported.
+    AF_UNSPEC = 0, ## unspecified domain (can be detected automatically by
+                   ## some procedures, such as getaddrinfo)
+    AF_UNIX = 1,   ## for local socket (using a file). Unsupported on Windows.
+    AF_INET = 2,   ## for network protocol IPv4 or
+    AF_INET6 = when defined(macosx): 30 elif defined(windows): 23 else: 10 ## for network protocol IPv6.
 
   SockType* = enum     ## second argument to `socket` proc
     SOCK_STREAM = 1,   ## reliable stream-oriented service or Stream Sockets
@@ -60,13 +75,14 @@ type
     SOCK_RAW = 3,      ## raw protocols atop the network layer.
     SOCK_SEQPACKET = 5 ## reliable sequenced packet service
 
-  Protocol* = enum      ## third argument to `socket` proc
-    IPPROTO_TCP = 6,    ## Transmission control protocol.
-    IPPROTO_UDP = 17,   ## User datagram protocol.
-    IPPROTO_IP,         ## Internet protocol. Unsupported on Windows.
-    IPPROTO_IPV6,       ## Internet Protocol Version 6. Unsupported on Windows.
-    IPPROTO_RAW,        ## Raw IP Packets Protocol. Unsupported on Windows.
-    IPPROTO_ICMP        ## Control message protocol. Unsupported on Windows.
+  Protocol* = enum    ## third argument to `socket` proc
+    IPPROTO_TCP = 6,  ## Transmission control protocol.
+    IPPROTO_UDP = 17, ## User datagram protocol.
+    IPPROTO_IP,       ## Internet protocol.
+    IPPROTO_IPV6,     ## Internet Protocol Version 6.
+    IPPROTO_RAW,      ## Raw IP Packets Protocol. Unsupported on Windows.
+    IPPROTO_ICMP      ## Internet Control message protocol.
+    IPPROTO_ICMPV6    ## Internet Control message protocol for IPv6.
 
   Servent* = object ## information about a service
     name*: string
@@ -81,8 +97,7 @@ type
     length*: int
     addrList*: seq[string]
 
-{.deprecated: [TPort: Port, TDomain: Domain, TType: SockType,
-    TProtocol: Protocol, TServent: Servent, THostent: Hostent].}
+const IPPROTO_NONE* = IPPROTO_IP ## Use this if your socket type requires a protocol value of zero (e.g. Unix sockets).
 
 when useWinVersion:
   let
@@ -92,7 +107,7 @@ when useWinVersion:
     IOCPARM_MASK* = 127
     IOC_IN* = int(-2147483648)
     FIONBIO* = IOC_IN.int32 or ((sizeof(int32) and IOCPARM_MASK) shl 16) or
-                             (102 shl 8) or 126
+               (102 shl 8) or 126
     nativeAfInet = winlean.AF_INET
     nativeAfInet6 = winlean.AF_INET6
 
@@ -104,88 +119,166 @@ else:
     osInvalidSocket* = posix.INVALID_SOCKET
     nativeAfInet = posix.AF_INET
     nativeAfInet6 = posix.AF_INET6
+    nativeAfUnix = posix.AF_UNIX
 
 proc `==`*(a, b: Port): bool {.borrow.}
-  ## ``==`` for ports.
+  ## `==` for ports.
 
 proc `$`*(p: Port): string {.borrow.}
-  ## returns the port number as a string
+  ## Returns the port number as a string
 
 proc toInt*(domain: Domain): cint
-  ## Converts the Domain enum to a platform-dependent ``cint``.
+  ## Converts the Domain enum to a platform-dependent `cint`.
 
 proc toInt*(typ: SockType): cint
-  ## Converts the SockType enum to a platform-dependent ``cint``.
+  ## Converts the SockType enum to a platform-dependent `cint`.
 
 proc toInt*(p: Protocol): cint
-  ## Converts the Protocol enum to a platform-dependent ``cint``.
+  ## Converts the Protocol enum to a platform-dependent `cint`.
 
 when not useWinVersion:
   proc toInt(domain: Domain): cint =
     case domain
-    of AF_UNIX:        result = posix.AF_UNIX
-    of AF_INET:        result = posix.AF_INET
-    of AF_INET6:       result = posix.AF_INET6
-    else: discard
+    of AF_UNSPEC: result = posix.AF_UNSPEC.cint
+    of AF_UNIX: result = posix.AF_UNIX.cint
+    of AF_INET: result = posix.AF_INET.cint
+    of AF_INET6: result = posix.AF_INET6.cint
+
+  proc toKnownDomain*(family: cint): Option[Domain] =
+    ## Converts the platform-dependent `cint` to the Domain or none(),
+    ## if the `cint` is not known.
+    result = if family == posix.AF_UNSPEC: some(Domain.AF_UNSPEC)
+             elif family == posix.AF_UNIX: some(Domain.AF_UNIX)
+             elif family == posix.AF_INET: some(Domain.AF_INET)
+             elif family == posix.AF_INET6: some(Domain.AF_INET6)
+             else: none(Domain)
 
   proc toInt(typ: SockType): cint =
     case typ
-    of SOCK_STREAM:    result = posix.SOCK_STREAM
-    of SOCK_DGRAM:     result = posix.SOCK_DGRAM
+    of SOCK_STREAM: result = posix.SOCK_STREAM
+    of SOCK_DGRAM: result = posix.SOCK_DGRAM
     of SOCK_SEQPACKET: result = posix.SOCK_SEQPACKET
-    of SOCK_RAW:       result = posix.SOCK_RAW
-    else: discard
+    of SOCK_RAW: result = posix.SOCK_RAW
 
   proc toInt(p: Protocol): cint =
     case p
-    of IPPROTO_TCP:    result = posix.IPPROTO_TCP
-    of IPPROTO_UDP:    result = posix.IPPROTO_UDP
-    of IPPROTO_IP:     result = posix.IPPROTO_IP
-    of IPPROTO_IPV6:   result = posix.IPPROTO_IPV6
-    of IPPROTO_RAW:    result = posix.IPPROTO_RAW
-    of IPPROTO_ICMP:   result = posix.IPPROTO_ICMP
-    else: discard
+    of IPPROTO_TCP: result = posix.IPPROTO_TCP
+    of IPPROTO_UDP: result = posix.IPPROTO_UDP
+    of IPPROTO_IP: result = posix.IPPROTO_IP
+    of IPPROTO_IPV6: result = posix.IPPROTO_IPV6
+    of IPPROTO_RAW: result = posix.IPPROTO_RAW
+    of IPPROTO_ICMP: result = posix.IPPROTO_ICMP
+    of IPPROTO_ICMPV6: result = posix.IPPROTO_ICMPV6
 
 else:
   proc toInt(domain: Domain): cint =
-    result = toU16(ord(domain))
+    result = cast[cint](uint32(ord(domain)))
+
+  proc toKnownDomain*(family: cint): Option[Domain] =
+    ## Converts the platform-dependent `cint` to the Domain or none(),
+    ## if the `cint` is not known.
+    result = if family == winlean.AF_UNSPEC: some(Domain.AF_UNSPEC)
+             elif family == winlean.AF_INET: some(Domain.AF_INET)
+             elif family == winlean.AF_INET6: some(Domain.AF_INET6)
+             else: none(Domain)
 
   proc toInt(typ: SockType): cint =
     result = cint(ord(typ))
 
   proc toInt(p: Protocol): cint =
-    result = cint(ord(p))
-
+    case p
+    of IPPROTO_IP:
+      result = 0.cint
+    of IPPROTO_ICMP:
+      result = 1.cint
+    of IPPROTO_TCP:
+      result = 6.cint
+    of IPPROTO_UDP:
+      result = 17.cint
+    of IPPROTO_IPV6:
+      result = 41.cint
+    of IPPROTO_ICMPV6:
+      result = 58.cint
+    else:
+      result = cint(ord(p))
+
+proc toSockType*(protocol: Protocol): SockType =
+  result = case protocol
+  of IPPROTO_TCP:
+    SOCK_STREAM
+  of IPPROTO_UDP:
+    SOCK_DGRAM
+  of IPPROTO_IP, IPPROTO_IPV6, IPPROTO_RAW, IPPROTO_ICMP, IPPROTO_ICMPV6:
+    SOCK_RAW
+
+proc getProtoByName*(name: string): int {.since: (1, 3, 5).} =
+  ## Returns a protocol code from the database that matches the protocol `name`.
+  when useWinVersion:
+    let protoent = winlean.getprotobyname(name.cstring)
+  else:
+    let protoent = posix.getprotobyname(name.cstring)
 
-proc newNativeSocket*(domain: Domain = AF_INET,
-                      sockType: SockType = SOCK_STREAM,
-                      protocol: Protocol = IPPROTO_TCP): SocketHandle =
-  ## Creates a new socket; returns `InvalidSocket` if an error occurs.
-  socket(toInt(domain), toInt(sockType), toInt(protocol))
+  if protoent == nil:
+    raise newException(OSError, "protocol not found: " & name)
 
-proc newNativeSocket*(domain: cint, sockType: cint,
-                      protocol: cint): SocketHandle =
-  ## Creates a new socket; returns `InvalidSocket` if an error occurs.
-  ##
-  ## Use this overload if one of the enums specified above does
-  ## not contain what you need.
-  socket(domain, sockType, protocol)
+  result = protoent.p_proto.int
 
 proc close*(socket: SocketHandle) =
-  ## closes a socket.
+  ## Closes a socket.
   when useWinVersion:
     discard winlean.closesocket(socket)
   else:
     discard posix.close(socket)
-  # TODO: These values should not be discarded. An EOS should be raised.
+  # TODO: These values should not be discarded. An OSError should be raised.
   # http://stackoverflow.com/questions/12463473/what-happens-if-you-call-close-on-a-bsd-socket-multiple-times
 
-proc bindAddr*(socket: SocketHandle, name: ptr SockAddr, namelen: SockLen): cint =
+when declared(setInheritable) or defined(nimdoc):
+  proc setInheritable*(s: SocketHandle, inheritable: bool): bool {.inline.} =
+    ## Set whether a socket is inheritable by child processes. Returns `true`
+    ## on success.
+    ##
+    ## This function is not implemented on all platform, test for availability
+    ## with `declared() <system.html#declared,untyped>`.
+    setInheritable(FileHandle s, inheritable)
+
+proc createNativeSocket*(domain: cint, sockType: cint, protocol: cint,
+                         inheritable: bool = defined(nimInheritHandles)): SocketHandle =
+  ## Creates a new socket; returns `osInvalidSocket` if an error occurs.
+  ##
+  ## `inheritable` decides if the resulting SocketHandle can be inherited
+  ## by child processes.
+  ##
+  ## Use this overload if one of the enums specified above does
+  ## not contain what you need.
+  let sockType =
+    when (defined(linux) or defined(bsd)) and not defined(nimdoc):
+      if inheritable: sockType and not SOCK_CLOEXEC else: sockType or SOCK_CLOEXEC
+    else:
+      sockType
+  result = socket(domain, sockType, protocol)
+  when declared(setInheritable) and not (defined(linux) or defined(bsd)):
+    if not setInheritable(result, inheritable):
+      close result
+      return osInvalidSocket
+
+proc createNativeSocket*(domain: Domain = AF_INET,
+                         sockType: SockType = SOCK_STREAM,
+                         protocol: Protocol = IPPROTO_TCP,
+                         inheritable: bool = defined(nimInheritHandles)): SocketHandle =
+  ## Creates a new socket; returns `osInvalidSocket` if an error occurs.
+  ##
+  ## `inheritable` decides if the resulting SocketHandle can be inherited
+  ## by child processes.
+  createNativeSocket(toInt(domain), toInt(sockType), toInt(protocol), inheritable)
+
+proc bindAddr*(socket: SocketHandle, name: ptr SockAddr,
+    namelen: SockLen): cint =
   result = bindSocket(socket, name, namelen)
 
-proc listen*(socket: SocketHandle, backlog = SOMAXCONN): cint {.tags: [ReadIOEffect].} =
-  ## Marks ``socket`` as accepting connections.
-  ## ``Backlog`` specifies the maximum length of the
+proc listen*(socket: SocketHandle, backlog = SOMAXCONN): cint {.tags: [
+    ReadIOEffect].} =
+  ## Marks `socket` as accepting connections.
+  ## `Backlog` specifies the maximum length of the
   ## queue of pending connections.
   when useWinVersion:
     result = winlean.listen(socket, cint(backlog))
@@ -197,257 +290,447 @@ proc getAddrInfo*(address: string, port: Port, domain: Domain = AF_INET,
                   protocol: Protocol = IPPROTO_TCP): ptr AddrInfo =
   ##
   ##
-  ## **Warning**: The resulting ``ptr TAddrInfo`` must be freed using ``dealloc``!
+  ## .. warning:: The resulting `ptr AddrInfo` must be freed using `freeAddrInfo`!
   var hints: AddrInfo
   result = nil
   hints.ai_family = toInt(domain)
   hints.ai_socktype = toInt(sockType)
   hints.ai_protocol = toInt(protocol)
   # OpenBSD doesn't support AI_V4MAPPED and doesn't define the macro AI_V4MAPPED.
-  # FreeBSD doesn't support AI_V4MAPPED but defines the macro.
+  # FreeBSD, Haiku don't support AI_V4MAPPED but defines the macro.
   # https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198092
-  when not defined(freebsd) or defined(openbsd):
+  # https://dev.haiku-os.org/ticket/14323
+  when not defined(freebsd) and not defined(openbsd) and not defined(netbsd) and
+      not defined(android) and not defined(haiku):
     if domain == AF_INET6:
       hints.ai_flags = AI_V4MAPPED
-  var gaiResult = getaddrinfo(address, $port, addr(hints), result)
+  let socketPort = if sockType == SOCK_RAW: "" else: $port
+  var gaiResult = getaddrinfo(address, socketPort.cstring, addr(hints), result)
   if gaiResult != 0'i32:
-    when useWinVersion:
+    when useWinVersion or defined(freertos) or defined(nuttx):
       raiseOSError(osLastError())
     else:
       raiseOSError(osLastError(), $gai_strerror(gaiResult))
 
-proc dealloc*(ai: ptr AddrInfo) =
-  freeaddrinfo(ai)
-
-proc ntohl*(x: int32): int32 =
-  ## Converts 32-bit integers from network to host byte order.
+proc ntohl*(x: uint32): uint32 =
+  ## Converts 32-bit unsigned integers from network to host byte order.
   ## On machines where the host byte order is the same as network byte order,
   ## this is a no-op; otherwise, it performs a 4-byte swap operation.
   when cpuEndian == bigEndian: result = x
-  else: result = (x shr 24'i32) or
-                 (x shr 8'i32 and 0xff00'i32) or
-                 (x shl 8'i32 and 0xff0000'i32) or
-                 (x shl 24'i32)
-
-proc ntohs*(x: int16): int16 =
-  ## Converts 16-bit integers from network to host byte order. On machines
-  ## where the host byte order is the same as network byte order, this is
-  ## a no-op; otherwise, it performs a 2-byte swap operation.
+  else: result = (x shr 24'u32) or
+                  (x shr 8'u32 and 0xff00'u32) or
+                  (x shl 8'u32 and 0xff0000'u32) or
+                  (x shl 24'u32)
+
+proc ntohs*(x: uint16): uint16 =
+  ## Converts 16-bit unsigned integers from network to host byte order. On
+  ## machines where the host byte order is the same as network byte order,
+  ## this is a no-op; otherwise, it performs a 2-byte swap operation.
   when cpuEndian == bigEndian: result = x
-  else: result = (x shr 8'i16) or (x shl 8'i16)
+  else: result = (x shr 8'u16) or (x shl 8'u16)
 
-template htonl*(x: int32): expr =
-  ## Converts 32-bit integers from host to network byte order. On machines
-  ## where the host byte order is the same as network byte order, this is
-  ## a no-op; otherwise, it performs a 4-byte swap operation.
+template htonl*(x: uint32): untyped =
+  ## Converts 32-bit unsigned integers from host to network byte order. On
+  ## machines where the host byte order is the same as network byte order,
+  ## this is a no-op; otherwise, it performs a 4-byte swap operation.
   nativesockets.ntohl(x)
 
-template htons*(x: int16): expr =
-  ## Converts 16-bit positive integers from host to network byte order.
+template htons*(x: uint16): untyped =
+  ## Converts 16-bit unsigned integers from host to network byte order.
   ## On machines where the host byte order is the same as network byte
   ## order, this is a no-op; otherwise, it performs a 2-byte swap operation.
   nativesockets.ntohs(x)
 
-proc getServByName*(name, proto: string): Servent {.tags: [ReadIOEffect].} =
-  ## Searches the database from the beginning and finds the first entry for
-  ## which the service name specified by ``name`` matches the s_name member
-  ## and the protocol name specified by ``proto`` matches the s_proto member.
-  ##
-  ## On posix this will search through the ``/etc/services`` file.
-  when useWinVersion:
-    var s = winlean.getservbyname(name, proto)
-  else:
-    var s = posix.getservbyname(name, proto)
-  if s == nil: raiseOSError(osLastError(), "Service not found.")
-  result.name = $s.s_name
-  result.aliases = cstringArrayToSeq(s.s_aliases)
-  result.port = Port(s.s_port)
-  result.proto = $s.s_proto
-
-proc getServByPort*(port: Port, proto: string): Servent {.tags: [ReadIOEffect].} =
-  ## Searches the database from the beginning and finds the first entry for
-  ## which the port specified by ``port`` matches the s_port member and the
-  ## protocol name specified by ``proto`` matches the s_proto member.
-  ##
-  ## On posix this will search through the ``/etc/services`` file.
-  when useWinVersion:
-    var s = winlean.getservbyport(ze(int16(port)).cint, proto)
-  else:
-    var s = posix.getservbyport(ze(int16(port)).cint, proto)
-  if s == nil: raiseOSError(osLastError(), "Service not found.")
-  result.name = $s.s_name
-  result.aliases = cstringArrayToSeq(s.s_aliases)
-  result.port = Port(s.s_port)
-  result.proto = $s.s_proto
-
-proc getHostByAddr*(ip: string): Hostent {.tags: [ReadIOEffect].} =
-  ## This function will lookup the hostname of an IP Address.
-  var myaddr: InAddr
-  myaddr.s_addr = inet_addr(ip)
-
-  when useWinVersion:
-    var s = winlean.gethostbyaddr(addr(myaddr), sizeof(myaddr).cuint,
-                                  cint(AF_INET))
-    if s == nil: raiseOSError(osLastError())
-  else:
-    var s = posix.gethostbyaddr(addr(myaddr), sizeof(myaddr).Socklen,
-                                cint(posix.AF_INET))
-    if s == nil:
-      raiseOSError(osLastError(), $hstrerror(h_errno))
-
-  result.name = $s.h_name
-  result.aliases = cstringArrayToSeq(s.h_aliases)
-  when useWinVersion:
-    result.addrtype = Domain(s.h_addrtype)
-  else:
-    if s.h_addrtype == posix.AF_INET:
-      result.addrtype = AF_INET
-    elif s.h_addrtype == posix.AF_INET6:
-      result.addrtype = AF_INET6
-    else:
-      raiseOSError(osLastError(), "unknown h_addrtype")
-  result.addrList = cstringArrayToSeq(s.h_addr_list)
-  result.length = int(s.h_length)
-
-proc getHostByName*(name: string): Hostent {.tags: [ReadIOEffect].} =
-  ## This function will lookup the IP address of a hostname.
-  when useWinVersion:
-    var s = winlean.gethostbyname(name)
-  else:
-    var s = posix.gethostbyname(name)
-  if s == nil: raiseOSError(osLastError())
-  result.name = $s.h_name
-  result.aliases = cstringArrayToSeq(s.h_aliases)
-  when useWinVersion:
-    result.addrtype = Domain(s.h_addrtype)
-  else:
-    if s.h_addrtype == posix.AF_INET:
-      result.addrtype = AF_INET
-    elif s.h_addrtype == posix.AF_INET6:
-      result.addrtype = AF_INET6
-    else:
-      raiseOSError(osLastError(), "unknown h_addrtype")
-  result.addrList = cstringArrayToSeq(s.h_addr_list)
-  result.length = int(s.h_length)
-
 proc getSockDomain*(socket: SocketHandle): Domain =
-  ## returns the socket's domain (AF_INET or AF_INET6).
-  var name: SockAddr
+  ## Returns the socket's domain (AF_INET or AF_INET6).
+  var name: Sockaddr_in6
   var namelen = sizeof(name).SockLen
   if getsockname(socket, cast[ptr SockAddr](addr(name)),
                  addr(namelen)) == -1'i32:
     raiseOSError(osLastError())
-  if name.sa_family == nativeAfInet:
-    result = AF_INET
-  elif name.sa_family == nativeAfInet6:
-    result = AF_INET6
-  else:
-    raiseOSError(osLastError(), "unknown socket family in getSockFamily")
-
-
-proc getAddrString*(sockAddr: ptr SockAddr): string =
-  ## return the string representation of address within sockAddr
-  if sockAddr.sa_family == nativeAfInet:
-    result = $inet_ntoa(cast[ptr Sockaddr_in](sockAddr).sin_addr)
-  elif sockAddr.sa_family == nativeAfInet6:
-    when not useWinVersion:
-      # TODO: Windows
-      result = newString(posix.INET6_ADDRSTRLEN)
-      let addr6 = addr cast[ptr Sockaddr_in6](sockAddr).sin6_addr
-      discard posix.inet_ntop(posix.AF_INET6, addr6, result.cstring,
-          result.len.int32)
-      if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
-        result = result.substr("::ffff:".len)
+  let knownDomain = toKnownDomain(name.sin6_family.cint)
+  if knownDomain.isSome:
+    result = knownDomain.get()
   else:
-    raiseOSError(osLastError(), "unknown socket family in getAddrString")
-
-
-proc getSockName*(socket: SocketHandle): Port =
-  ## returns the socket's associated port number.
-  var name: Sockaddr_in
-  when useWinVersion:
-    name.sin_family = int16(ord(AF_INET))
-  else:
-    name.sin_family = posix.AF_INET
-  #name.sin_port = htons(cint16(port))
-  #name.sin_addr.s_addr = htonl(INADDR_ANY)
-  var namelen = sizeof(name).SockLen
-  if getsockname(socket, cast[ptr SockAddr](addr(name)),
-                 addr(namelen)) == -1'i32:
-    raiseOSError(osLastError())
-  result = Port(nativesockets.ntohs(name.sin_port))
-
-proc getLocalAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
-  ## returns the socket's local address and port number.
-  ##
-  ## Similar to POSIX's `getsockname`:idx:.
-  case domain
-  of AF_INET:
-    var name: Sockaddr_in
+    raise newException(IOError, "Unknown socket family in getSockDomain")
+
+when not useNimNetLite:
+  proc getServByName*(name, proto: string): Servent {.tags: [ReadIOEffect].} =
+    ## Searches the database from the beginning and finds the first entry for
+    ## which the service name specified by `name` matches the s_name member
+    ## and the protocol name specified by `proto` matches the s_proto member.
+    ##
+    ## On posix this will search through the `/etc/services` file.
     when useWinVersion:
-      name.sin_family = int16(ord(AF_INET))
+      var s = winlean.getservbyname(name, proto)
     else:
-      name.sin_family = posix.AF_INET
-    var namelen = sizeof(name).SockLen
-    if getsockname(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
-      raiseOSError(osLastError())
-    result = ($inet_ntoa(name.sin_addr),
-              Port(nativesockets.ntohs(name.sin_port)))
-  of AF_INET6:
-    var name: Sockaddr_in6
+      var s = posix.getservbyname(name, proto)
+    if s == nil: raiseOSError(osLastError(), "Service not found.")
+    result.name = $s.s_name
+    result.aliases = cstringArrayToSeq(s.s_aliases)
+    result.port = Port(s.s_port)
+    result.proto = $s.s_proto
+
+  proc getServByPort*(port: Port, proto: string): Servent {.tags: [ReadIOEffect].} =
+    ## Searches the database from the beginning and finds the first entry for
+    ## which the port specified by `port` matches the s_port member and the
+    ## protocol name specified by `proto` matches the s_proto member.
+    ##
+    ## On posix this will search through the `/etc/services` file.
     when useWinVersion:
-      name.sin6_family = int16(ord(AF_INET6))
+      var s = winlean.getservbyport(uint16(port).cint, proto)
     else:
-      name.sin6_family = posix.AF_INET6
-    var namelen = sizeof(name).SockLen
-    if getsockname(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
-      raiseOSError(osLastError())
-    # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
-    var buf: array[64, char]
-    if inet_ntop(name.sin6_family.cint,
-                 addr name, buf.cstring, sizeof(buf).int32).isNil:
-      raiseOSError(osLastError())
-    result = ($buf, Port(nativesockets.ntohs(name.sin6_port)))
-  else:
-    raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+      var s = posix.getservbyport(uint16(port).cint, proto)
+    if s == nil: raiseOSError(osLastError(), "Service not found.")
+    result.name = $s.s_name
+    result.aliases = cstringArrayToSeq(s.s_aliases)
+    result.port = Port(s.s_port)
+    result.proto = $s.s_proto
+
+  proc getHostByAddr*(ip: string): Hostent {.tags: [ReadIOEffect].} =
+    ## This function will lookup the hostname of an IP Address.
+    var
+      addrInfo = getAddrInfo(ip, Port(0), AF_UNSPEC)
+      myAddr: pointer
+      addrLen = 0
+      family = 0
+    
+    defer: freeAddrInfo(addrInfo)
+
+    if addrInfo.ai_addr.sa_family.cint == nativeAfInet:
+      family = nativeAfInet
+      myAddr = addr cast[ptr Sockaddr_in](addrInfo.ai_addr).sin_addr
+      addrLen = 4
+    elif addrInfo.ai_addr.sa_family.cint == nativeAfInet6:
+      family = nativeAfInet6
+      myAddr = addr cast[ptr Sockaddr_in6](addrInfo.ai_addr).sin6_addr
+      addrLen = 16
+    else:
+      raise newException(IOError, "Unknown socket family in `getHostByAddr()`")
 
-proc getPeerAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
-  ## returns the socket's peer address and port number.
-  ##
-  ## Similar to POSIX's `getpeername`:idx:
-  case domain
-  of AF_INET:
-    var name: Sockaddr_in
     when useWinVersion:
-      name.sin_family = int16(ord(AF_INET))
+      var s = winlean.gethostbyaddr(cast[ptr InAddr](myAddr), addrLen.cuint,
+                                    cint(family))
+      if s == nil: raiseOSError(osLastError())
     else:
-      name.sin_family = posix.AF_INET
-    var namelen = sizeof(name).SockLen
-    if getpeername(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
+      var s =
+        when defined(android4):
+          posix.gethostbyaddr(cast[cstring](myAddr), addrLen.cint,
+                              cint(family))
+        else:
+          posix.gethostbyaddr(myAddr, addrLen.SockLen,
+                              cint(family))
+      if s == nil:
+        raiseOSError(osLastError(), $hstrerror(h_errno))
+
+    result.name = $s.h_name
+    result.aliases = cstringArrayToSeq(s.h_aliases)
+    when useWinVersion:
+      result.addrtype = Domain(s.h_addrtype)
+    else:
+      if s.h_addrtype == posix.AF_INET:
+        result.addrtype = AF_INET
+      elif s.h_addrtype == posix.AF_INET6:
+        result.addrtype = AF_INET6
+      else:
+        raiseOSError(osLastError(), "unknown h_addrtype")
+    if result.addrtype == AF_INET:
+      result.addrList = @[]
+      var i = 0
+      while not isNil(s.h_addr_list[i]):
+        var inaddrPtr = cast[ptr InAddr](s.h_addr_list[i])
+        result.addrList.add($inet_ntoa(inaddrPtr[]))
+        inc(i)
+    else:
+      let strAddrLen = when not useWinVersion: posix.INET6_ADDRSTRLEN.int
+                       else: 46
+      var i = 0
+      while not isNil(s.h_addr_list[i]):
+        var ipStr = newString(strAddrLen)
+        if inet_ntop(nativeAfInet6, cast[pointer](s.h_addr_list[i]),
+                     cstring(ipStr), len(ipStr).int32) == nil:
+          raiseOSError(osLastError())
+        when not useWinVersion:
+          if posix.IN6_IS_ADDR_V4MAPPED(cast[ptr In6Addr](s.h_addr_list[i])) != 0:
+            ipStr.setSlice("::ffff:".len..<strAddrLen)
+        setLen(ipStr, len(cstring(ipStr)))
+        result.addrList.add(ipStr)
+        inc(i)
+    result.length = int(s.h_length)
+
+  proc getHostByName*(name: string): Hostent {.tags: [ReadIOEffect].} =
+    ## This function will lookup the IP address of a hostname.
+    when useWinVersion:
+      var s = winlean.gethostbyname(name)
+    else:
+      var s = posix.gethostbyname(name)
+    if s == nil: raiseOSError(osLastError())
+    result.name = $s.h_name
+    result.aliases = cstringArrayToSeq(s.h_aliases)
+    when useWinVersion:
+      result.addrtype = Domain(s.h_addrtype)
+    else:
+      if s.h_addrtype == posix.AF_INET:
+        result.addrtype = AF_INET
+      elif s.h_addrtype == posix.AF_INET6:
+        result.addrtype = AF_INET6
+      else:
+        raiseOSError(osLastError(), "unknown h_addrtype")
+    if result.addrtype == AF_INET:
+      result.addrList = @[]
+      var i = 0
+      while not isNil(s.h_addr_list[i]):
+        var inaddrPtr = cast[ptr InAddr](s.h_addr_list[i])
+        result.addrList.add($inet_ntoa(inaddrPtr[]))
+        inc(i)
+    else:
+      result.addrList = cstringArrayToSeq(s.h_addr_list)
+    result.length = int(s.h_length)
+
+  proc getHostname*(): string {.tags: [ReadIOEffect].} =
+    ## Returns the local hostname (not the FQDN)
+    # https://tools.ietf.org/html/rfc1035#section-2.3.1
+    # https://tools.ietf.org/html/rfc2181#section-11
+    const size = 256
+    result = newString(size)
+    when useWinVersion:
+      let success = winlean.gethostname(result.cstring, size)
+    else:
+      # Posix
+      let success = posix.gethostname(result.cstring, size)
+    if success != 0.cint:
       raiseOSError(osLastError())
-    result = ($inet_ntoa(name.sin_addr),
-              Port(nativesockets.ntohs(name.sin_port)))
-  of AF_INET6:
-    var name: Sockaddr_in6
+    let x = len(cstring(result))
+    result.setLen(x)
+
+  proc getAddrString*(sockAddr: ptr SockAddr): string =
+    ## Returns the string representation of address within sockAddr
+    if sockAddr.sa_family.cint == nativeAfInet:
+      result = $inet_ntoa(cast[ptr Sockaddr_in](sockAddr).sin_addr)
+    elif sockAddr.sa_family.cint == nativeAfInet6:
+      let addrLen = when not useWinVersion: posix.INET6_ADDRSTRLEN.int
+                    else: 46 # it's actually 46 in both cases
+      result = newString(addrLen)
+      let addr6 = addr cast[ptr Sockaddr_in6](sockAddr).sin6_addr
+      when not useWinVersion:
+        if posix.inet_ntop(posix.AF_INET6, addr6, cast[cstring](addr result[0]),
+                          result.len.int32) == nil:
+          raiseOSError(osLastError())
+        if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
+          result.setSlice("::ffff:".len..<addrLen)
+      else:
+        if winlean.inet_ntop(winlean.AF_INET6, addr6, cast[cstring](addr result[0]),
+                            result.len.int32) == nil:
+          raiseOSError(osLastError())
+      setLen(result, len(cstring(result)))
+    else:
+      when defined(posix) and not defined(nimdoc):
+        if sockAddr.sa_family.cint == nativeAfUnix:
+          return "unix"
+      raise newException(IOError, "Unknown socket family in getAddrString")
+
+  proc getAddrString*(sockAddr: ptr SockAddr, strAddress: var string) =
+    ## Stores in `strAddress` the string representation of the address inside
+    ## `sockAddr`
+    ##
+    ## **Note**
+    ## * `strAddress` must be initialized to 46 in length.
+    const length = 46
+    assert(length == len(strAddress),
+          "`strAddress` was not initialized correctly. 46 != `len(strAddress)`")
+    if sockAddr.sa_family.cint == nativeAfInet:
+      let addr4 = addr cast[ptr Sockaddr_in](sockAddr).sin_addr
+      when not useWinVersion:
+        if posix.inet_ntop(posix.AF_INET, addr4, cast[cstring](addr strAddress[0]),
+                          strAddress.len.int32) == nil:
+          raiseOSError(osLastError())
+      else:
+        if winlean.inet_ntop(winlean.AF_INET, addr4, cast[cstring](addr strAddress[0]),
+                            strAddress.len.int32) == nil:
+          raiseOSError(osLastError())
+    elif sockAddr.sa_family.cint == nativeAfInet6:
+      let addr6 = addr cast[ptr Sockaddr_in6](sockAddr).sin6_addr
+      when not useWinVersion:
+        if posix.inet_ntop(posix.AF_INET6, addr6, cast[cstring](addr strAddress[0]),
+                          strAddress.len.int32) == nil:
+          raiseOSError(osLastError())
+        if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
+          strAddress.setSlice("::ffff:".len..<length)
+      else:
+        if winlean.inet_ntop(winlean.AF_INET6, addr6, cast[cstring](addr strAddress[0]),
+                            strAddress.len.int32) == nil:
+          raiseOSError(osLastError())
+    else:
+      raise newException(IOError, "Unknown socket family in getAddrString")
+    setLen(strAddress, len(cstring(strAddress)))
+
+  when defined(posix) and not defined(nimdoc):
+    proc makeUnixAddr*(path: string): Sockaddr_un =
+      result.sun_family = AF_UNIX.TSa_Family
+      if path.len >= Sockaddr_un_path_length:
+        raise newException(ValueError, "socket path too long")
+      copyMem(addr result.sun_path, path.cstring, path.len + 1)
+
+  proc getSockName*(socket: SocketHandle): Port =
+    ## Returns the socket's associated port number.
+    var name: Sockaddr_in
     when useWinVersion:
-      name.sin6_family = int16(ord(AF_INET6))
+      name.sin_family = uint16(ord(AF_INET))
     else:
-      name.sin6_family = posix.AF_INET6
+      name.sin_family = TSa_Family(posix.AF_INET)
+    #name.sin_port = htons(cint16(port))
+    #name.sin_addr.s_addr = htonl(INADDR_ANY)
     var namelen = sizeof(name).SockLen
-    if getpeername(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
+    if getsockname(socket, cast[ptr SockAddr](addr(name)),
+                  addr(namelen)) == -1'i32:
       raiseOSError(osLastError())
-    # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
-    var buf: array[64, char]
-    if inet_ntop(name.sin6_family.cint,
-                 addr name, buf.cstring, sizeof(buf).int32).isNil:
+    result = Port(nativesockets.ntohs(name.sin_port))
+
+  proc getLocalAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
+    ## Returns the socket's local address and port number.
+    ##
+    ## Similar to POSIX's `getsockname`:idx:.
+    case domain
+    of AF_INET:
+      var name: Sockaddr_in
+      when useWinVersion:
+        name.sin_family = uint16(ord(AF_INET))
+      else:
+        name.sin_family = TSa_Family(posix.AF_INET)
+      var namelen = sizeof(name).SockLen
+      if getsockname(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      result = ($inet_ntoa(name.sin_addr),
+                Port(nativesockets.ntohs(name.sin_port)))
+    of AF_INET6:
+      var name: Sockaddr_in6
+      when useWinVersion:
+        name.sin6_family = uint16(ord(AF_INET6))
+      else:
+        name.sin6_family = TSa_Family(posix.AF_INET6)
+      var namelen = sizeof(name).SockLen
+      if getsockname(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
+      result[0] = newString(64)
+      if inet_ntop(name.sin6_family.cint,
+          addr name.sin6_addr, cast[cstring](addr result[0][0]), (result[0].len+1).int32).isNil:
+        raiseOSError(osLastError())
+      setLen(result[0], result[0].cstring.len)
+      result[1] = Port(nativesockets.ntohs(name.sin6_port))
+    else:
+      raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+
+  proc getPeerAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
+    ## Returns the socket's peer address and port number.
+    ##
+    ## Similar to POSIX's `getpeername`:idx:
+    case domain
+    of AF_INET:
+      var name: Sockaddr_in
+      when useWinVersion:
+        name.sin_family = uint16(ord(AF_INET))
+      else:
+        name.sin_family = TSa_Family(posix.AF_INET)
+      var namelen = sizeof(name).SockLen
+      if getpeername(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      result = ($inet_ntoa(name.sin_addr),
+                Port(nativesockets.ntohs(name.sin_port)))
+    of AF_INET6:
+      var name: Sockaddr_in6
+      when useWinVersion:
+        name.sin6_family = uint16(ord(AF_INET6))
+      else:
+        name.sin6_family = TSa_Family(posix.AF_INET6)
+      var namelen = sizeof(name).SockLen
+      if getpeername(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
+      result[0] = newString(64)
+      if inet_ntop(name.sin6_family.cint,
+          addr name.sin6_addr, cast[cstring](addr result[0][0]), (result[0].len+1).int32).isNil:
+        raiseOSError(osLastError())
+      setLen(result[0], result[0].cstring.len)
+      result[1] = Port(nativesockets.ntohs(name.sin6_port))
+    else:
+      raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+
+when useNimNetLite: 
+
+  when useWinVersion:
+    const
+      INET_ADDRSTRLEN = 16
+      INET6_ADDRSTRLEN = 46 # it's actually 46 in both cases
+
+  proc sockAddrToStr(sa: ptr SockAddr): string {.noinit.} =
+    let af_family = sa.sa_family
+    var nl, v4Slice: cint
+    var si_addr: ptr InAddr
+
+    if af_family == AF_INET.TSa_Family:
+      nl = INET_ADDRSTRLEN
+      si_addr = cast[ptr Sockaddr_in](sa).sin_addr.addr()
+    elif af_family == AF_INET6.TSa_Family:
+      nl = INET6_ADDRSTRLEN
+      let si6_addr = cast[ptr Sockaddr_in6](sa).sin6_addr.addr()
+      si_addr = cast[ptr InAddr](si6_addr) # let's us reuse logic below 
+      when defined(posix) and not defined(nimdoc) and not defined(zephyr):
+        if posix.IN6_IS_ADDR_V4MAPPED(si6_addr) != 0:
+          v4Slice = "::ffff:".len()
+    else:
+      when defined(posix) and not defined(nimdoc):
+        if af_family.cint == nativeAfUnix:
+          return "unix"
+      return ""
+
+    result = newString(nl)
+    let namePtr = result.cstring()
+    if namePtr == inet_ntop(af_family.cint, si_addr, namePtr, nl):
+      result.setLen(len(namePtr))
+      if v4Slice > 0: result.setSlice(v4Slice.int ..< nl.int)
+    else:
+      return ""
+
+  proc sockAddrToStr(sa: var Sockaddr_in | var Sockaddr_in6): string =
+    result = sockAddrToStr(cast[ptr SockAddr](unsafeAddr(sa)))
+
+  proc getAddrString*(sockAddr: ptr SockAddr): string =
+    result = sockAddrToStr(sockAddr)
+    if result.len() == 0:
       raiseOSError(osLastError())
-    result = ($buf, Port(nativesockets.ntohs(name.sin6_port)))
-  else:
-    raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+
+  proc getAddrString*(sockAddr: ptr SockAddr, strAddress: var string) {.noinit.} =
+    strAddress = getAddrString(sockAddr)
+
+  proc getLocalAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
+    ## Returns the socket's local address and port number.
+    ##
+    ## Similar to POSIX's `getsockname`:idx:.
+    template sockGetNameOrRaiseError(socket: untyped, name: untyped) =
+      var namelen = sizeof(socket).SockLen
+      if getsockname(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+
+    case domain
+    of AF_INET:
+      var name = Sockaddr_in(sin_family: TSa_Family(posix.AF_INET))
+      sockGetNameOrRaiseError(socket, name)
+      result = (sockAddrToStr(name),
+                Port(nativesockets.ntohs(name.sin_port)))
+    of AF_INET6:
+      var name = Sockaddr_in6(sin6_family: TSa_Family(posix.AF_INET6))
+      sockGetNameOrRaiseError(socket, name)
+      result = (sockAddrToStr(name),
+                Port(nativesockets.ntohs(name.sin6_port)))
+    else:
+      raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+
 
 proc getSockOptInt*(socket: SocketHandle, level, optname: int): int {.
   tags: [ReadIOEffect].} =
@@ -470,7 +753,7 @@ proc setSockOptInt*(socket: SocketHandle, level, optname, optval: int) {.
 proc setBlocking*(s: SocketHandle, blocking: bool) =
   ## Sets blocking mode on socket.
   ##
-  ## Raises EOS on error.
+  ## Raises OSError on error.
   when useWinVersion:
     var mode = clong(ord(not blocking)) # 1 for non-blocking, 0 for blocking
     if ioctlsocket(s, FIONBIO, addr(mode)) == -1:
@@ -487,8 +770,12 @@ proc setBlocking*(s: SocketHandle, blocking: bool) =
 proc timeValFromMilliseconds(timeout = 500): Timeval =
   if timeout != -1:
     var seconds = timeout div 1000
-    result.tv_sec = seconds.int32
-    result.tv_usec = ((timeout - seconds * 1000) * 1000).int32
+    when useWinVersion:
+      result.tv_sec = seconds.int32
+      result.tv_usec = ((timeout - seconds * 1000) * 1000).int32
+    else:
+      result.tv_sec = seconds.Time
+      result.tv_usec = ((timeout - seconds * 1000) * 1000).Suseconds
 
 proc createFdSet(fd: var TFdSet, s: seq[SocketHandle], m: var int) =
   FD_ZERO(fd)
@@ -507,15 +794,15 @@ proc pruneSocketSet(s: var seq[SocketHandle], fd: var TFdSet) =
       inc(i)
   setLen(s, L)
 
-proc select*(readfds: var seq[SocketHandle], timeout = 500): int =
-  ## Traditional select function. This function will return the number of
-  ## sockets that are ready to be read from, written to, or which have errors.
-  ## If there are none; 0 is returned.
-  ## ``Timeout`` is in milliseconds and -1 can be specified for no timeout.
+proc selectRead*(readfds: var seq[SocketHandle], timeout = 500): int =
+  ## When a socket in `readfds` is ready to be read from then a non-zero
+  ## value will be returned specifying the count of the sockets which can be
+  ## read from. The sockets which cannot be read from will also be removed
+  ## from `readfds`.
   ##
-  ## A socket is removed from the specific ``seq`` when it has data waiting to
-  ## be read/written to or has errors (``exceptfds``).
-  var tv {.noInit.}: Timeval = timeValFromMilliseconds(timeout)
+  ## `timeout` is specified in milliseconds and `-1` can be specified for
+  ## an unlimited time.
+  var tv {.noinit.}: Timeval = timeValFromMilliseconds(timeout)
 
   var rd: TFdSet
   var m = 0
@@ -530,14 +817,14 @@ proc select*(readfds: var seq[SocketHandle], timeout = 500): int =
 
 proc selectWrite*(writefds: var seq[SocketHandle],
                   timeout = 500): int {.tags: [ReadIOEffect].} =
-  ## When a socket in ``writefds`` is ready to be written to then a non-zero
+  ## When a socket in `writefds` is ready to be written to then a non-zero
   ## value will be returned specifying the count of the sockets which can be
-  ## written to. The sockets which can be written to will also be removed
-  ## from ``writefds``.
+  ## written to. The sockets which cannot be written to will also be removed
+  ## from `writefds`.
   ##
-  ## ``timeout`` is specified in milliseconds and ``-1`` can be specified for
+  ## `timeout` is specified in milliseconds and `-1` can be specified for
   ## an unlimited time.
-  var tv {.noInit.}: Timeval = timeValFromMilliseconds(timeout)
+  var tv {.noinit.}: Timeval = timeValFromMilliseconds(timeout)
 
   var wr: TFdSet
   var m = 0
@@ -550,6 +837,34 @@ proc selectWrite*(writefds: var seq[SocketHandle],
 
   pruneSocketSet(writefds, (wr))
 
-when defined(Windows):
+proc accept*(fd: SocketHandle, inheritable = defined(nimInheritHandles)): (SocketHandle, string) =
+  ## Accepts a new client connection.
+  ##
+  ## `inheritable` decides if the resulting SocketHandle can be inherited by
+  ## child processes.
+  ##
+  ## Returns (osInvalidSocket, "") if an error occurred.
+  var sockAddress: SockAddr
+  var addrLen = sizeof(sockAddress).SockLen
+  var sock =
+    when (defined(linux) or defined(bsd)) and not defined(nimdoc):
+      accept4(fd, addr(sockAddress), addr(addrLen),
+              if inheritable: 0 else: SOCK_CLOEXEC)
+    else:
+      accept(fd, addr(sockAddress), addr(addrLen))
+  when declared(setInheritable) and not (defined(linux) or defined(bsd)):
+    if not setInheritable(sock, inheritable):
+      close sock
+      sock = osInvalidSocket
+  if sock == osInvalidSocket:
+    return (osInvalidSocket, "")
+  else:
+    when useNimNetLite:
+      var name = sockAddrToStr(addr sockAddress)
+      return (sock, name)
+    else:
+      return (sock, $inet_ntoa(cast[Sockaddr_in](sockAddress).sin_addr))
+
+when defined(windows):
   var wsa: WSAData
   if wsaStartup(0x0101'i16, addr wsa) != 0: raiseOSError(osLastError())