Add Zephyr Support (#19003)

* Porting Nim to run on Zephyr.

Includes changes to `std/net`.

Squashed commit of the following:
    tweaking more memory / malloc things
    revert back bitmasks
    tweaking nim to use kernel heap as C malloc doesn't work
    fixing socket polling on zephyr
    cleanup getting maximum sockets for process or for rtos'es
    reorganizing and fixing net for async / system
    merge netlite changes back into nativesockets
    merge netlite changes back into nativesockets
    reverting native sockets back
    tweaking nim / zephyr network
    adding option to run 'net-lite' from linux
    bridging zephyr's max connections
    fixing net errors
    fixing compilation with getAddrString
    fixing compilation with getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ...
    add note regarding incorrect FreeRTOS Sockadd_in fields
    changing to NIM_STATIC_ASSERT
    cleaning up the static_assert error messages
    cleaning up the static_assert error messages
    setting up static assert ftw!
    testing compile time asserts
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    finding missing items (issue  #18684)
    fixup posix constants (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)

* fixing constant capitalizations

* remove extra debug prints and fix TSa_Family/cint issue

* remove extra debug prints and fix TSa_Family/cint issue

* Porting Nim to run on Zephyr.

Includes changes to `std/net`.

Squashed commit of the following:
    tweaking more memory / malloc things
    revert back bitmasks
    tweaking nim to use kernel heap as C malloc doesn't work
    fixing socket polling on zephyr
    cleanup getting maximum sockets for process or for rtos'es
    reorganizing and fixing net for async / system
    merge netlite changes back into nativesockets
    merge netlite changes back into nativesockets
    reverting native sockets back
    tweaking nim / zephyr network
    adding option to run 'net-lite' from linux
    bridging zephyr's max connections
    fixing net errors
    fixing compilation with getAddrString
    fixing compilation with getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ...
    add note regarding incorrect FreeRTOS Sockadd_in fields
    changing to NIM_STATIC_ASSERT
    cleaning up the static_assert error messages
    cleaning up the static_assert error messages
    setting up static assert ftw!
    testing compile time asserts
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    finding missing items (issue  #18684)
    fixup posix constants (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)

* fixing constant capitalizations

* remove extra debug prints and fix TSa_Family/cint issue

* remove extra debug prints and fix TSa_Family/cint issue

* fixing PR issues

* Porting Nim to run on Zephyr.

Includes changes to `std/net`.

Squashed commit of the following:
    tweaking more memory / malloc things
    revert back bitmasks
    tweaking nim to use kernel heap as C malloc doesn't work
    fixing socket polling on zephyr
    cleanup getting maximum sockets for process or for rtos'es
    reorganizing and fixing net for async / system
    merge netlite changes back into nativesockets
    merge netlite changes back into nativesockets
    reverting native sockets back
    tweaking nim / zephyr network
    adding option to run 'net-lite' from linux
    bridging zephyr's max connections
    fixing net errors
    fixing compilation with getAddrString
    fixing compilation with getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getAddrString
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ... getLocalAddr
    experimenting with a nativesockets_lite ...
    add note regarding incorrect FreeRTOS Sockadd_in fields
    changing to NIM_STATIC_ASSERT
    cleaning up the static_assert error messages
    cleaning up the static_assert error messages
    setting up static assert ftw!
    testing compile time asserts
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    reworking Sockaddr objects to more closely match various platforms
    finding missing items (issue  #18684)
    fixup posix constants (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)
    adding plumbing for zephyr os (issue  #18684)

* fixing constant capitalizations

* remove extra debug prints and fix TSa_Family/cint issue

* remove extra debug prints and fix TSa_Family/cint issue

* Remerge

* fixing constant capitalizations

* remove extra debug prints and fix TSa_Family/cint issue

* remove extra debug prints and fix TSa_Family/cint issue

* fixing PR issues

* fix maxDescriptors on zephyr/freertos

* move maxDescriptors to selector.nim -- fixes compile issue

* change realloc impl on zephyr to match ansi c behavior

* change realloc impl on zephyr to match ansi c behavior

* force compileOnly mode for tlwip

Co-authored-by: Jaremy J. Creechley <jaremy.creechley@wavebaselabs.com>
Co-authored-by: Jaremy Creechley <jaremy.creechley@panthalassa.com>

8 files changed, 388 insertions, 286 deletions

diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index d87e2360f..e15fb0851 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -1973,15 +1973,18 @@ proc activeDescriptors*(): int {.inline.} =
 when defined(posix):
   import posix
 
-when defined(linux) or defined(windows) or defined(macosx) or defined(bsd):
+when defined(linux) or defined(windows) or defined(macosx) or defined(bsd) or
+       defined(zephyr) or defined(freertos):
   proc maxDescriptors*(): int {.raises: OSError.} =
     ## Returns the maximum number of active file descriptors for the current
     ## process. This involves a system call. For now `maxDescriptors` is
     ## supported on the following OSes: Windows, Linux, OSX, BSD.
     when defined(windows):
       result = 16_700_000
+    elif defined(zephyr) or defined(freertos):
+      result = FD_MAX
     else:
       var fdLim: RLimit
       if getrlimit(RLIMIT_NOFILE, fdLim) < 0:
         raiseOSError(osLastError())
-      result = int(fdLim.rlim_cur) - 1
+      result = int(fdLim.rlim_cur) - 1
\ No newline at end of file
diff --git a/lib/pure/asyncnet.nim b/lib/pure/asyncnet.nim
index 5523fa10e..abb4dd075 100644
--- a/lib/pure/asyncnet.nim
+++ b/lib/pure/asyncnet.nim
@@ -103,6 +103,7 @@ export SOBool
 # TODO: Remove duplication introduced by PR #4683.
 
 const defineSsl = defined(ssl) or defined(nimdoc)
+const useNimNetLite = defined(nimNetLite) or defined(freertos) or defined(zephyr)
 
 when defineSsl:
   import openssl
@@ -178,11 +179,12 @@ proc getLocalAddr*(socket: AsyncSocket): (string, Port) =
   ## This is high-level interface for `getsockname`:idx:.
   getLocalAddr(socket.fd, socket.domain)
 
-proc getPeerAddr*(socket: AsyncSocket): (string, Port) =
-  ## Get the socket's peer address and port number.
-  ##
-  ## This is high-level interface for `getpeername`:idx:.
-  getPeerAddr(socket.fd, socket.domain)
+when not useNimNetLite:
+  proc getPeerAddr*(socket: AsyncSocket): (string, Port) =
+    ## Get the socket's peer address and port number.
+    ##
+    ## This is high-level interface for `getpeername`:idx:.
+    getPeerAddr(socket.fd, socket.domain)
 
 proc newAsyncSocket*(domain, sockType, protocol: cint,
                      buffered = true,
@@ -655,7 +657,7 @@ proc hasDataBuffered*(s: AsyncSocket): bool {.since: (1, 5).} =
   # xxx dedup with std/net
   s.isBuffered and s.bufLen > 0 and s.currPos != s.bufLen
 
-when defined(posix):
+when defined(posix) and not useNimNetLite:
 
   proc connectUnix*(socket: AsyncSocket, path: string): owned(Future[void]) =
     ## Binds Unix socket to `path`.
diff --git a/lib/pure/ioselects/ioselectors_epoll.nim b/lib/pure/ioselects/ioselectors_epoll.nim
index b62b4c2db..05d9d19a8 100644
--- a/lib/pure/ioselects/ioselectors_epoll.nim
+++ b/lib/pure/ioselects/ioselectors_epoll.nim
@@ -73,10 +73,7 @@ type
 
 proc newSelector*[T](): Selector[T] =
   # Retrieve the maximum fd count (for current OS) via getrlimit()
-  var a = RLimit()
-  if getrlimit(posix.RLIMIT_NOFILE, a) != 0:
-    raiseOSError(osLastError())
-  var maxFD = int(a.rlim_max)
+  var maxFD = maxDescriptors()
   doAssert(maxFD > 0)
   # Start with a reasonable size, checkFd() will grow this on demand
   const numFD = 1024
diff --git a/lib/pure/ioselects/ioselectors_poll.nim b/lib/pure/ioselects/ioselectors_poll.nim
index 6b10e19ae..0d8fef78a 100644
--- a/lib/pure/ioselects/ioselectors_poll.nim
+++ b/lib/pure/ioselects/ioselectors_poll.nim
@@ -53,10 +53,7 @@ else:
     body
 
 proc newSelector*[T](): Selector[T] =
-  var a = RLimit()
-  if getrlimit(posix.RLIMIT_NOFILE, a) != 0:
-    raiseIOSelectorsError(osLastError())
-  var maxFD = int(a.rlim_max)
+  var maxFD = maxDescriptors()
 
   when hasThreadSupport:
     result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
diff --git a/lib/pure/ioselects/ioselectors_select.nim b/lib/pure/ioselects/ioselectors_select.nim
index 6f216ac85..88cbaf28c 100644
--- a/lib/pure/ioselects/ioselectors_select.nim
+++ b/lib/pure/ioselects/ioselectors_select.nim
@@ -313,7 +313,7 @@ proc selectInto*[T](s: Selector[T], timeout: int,
   verifySelectParams(timeout)
 
   if timeout != -1:
-    when defined(genode) or defined(freertos):
+    when defined(genode) or defined(freertos) or defined(zephyr):
       tv.tv_sec = Time(timeout div 1_000)
     else:
       tv.tv_sec = timeout.int32 div 1_000
diff --git a/lib/pure/nativesockets.nim b/lib/pure/nativesockets.nim
index 13c08dd92..4037d7181 100644
--- a/lib/pure/nativesockets.nim
+++ b/lib/pure/nativesockets.nim
@@ -21,6 +21,7 @@ when hostOS == "solaris":
   {.passl: "-lsocket -lnsl".}
 
 const useWinVersion = defined(windows) or defined(nimdoc)
+const useNimNetLite = defined(nimNetLite) or defined(freertos) or defined(zephyr)
 
 when useWinVersion:
   import winlean
@@ -35,9 +36,12 @@ else:
 
 export SocketHandle, Sockaddr_in, Addrinfo, INADDR_ANY, SockAddr, SockLen,
   Sockaddr_in6, Sockaddr_storage,
-  inet_ntoa, recv, `==`, connect, send, accept, recvfrom, sendto,
+  recv, `==`, connect, send, accept, recvfrom, sendto,
   freeAddrInfo
 
+when not useNimNetLite:
+  export inet_ntoa
+
 export
   SO_ERROR,
   SOL_SOCKET,
@@ -332,125 +336,6 @@ template htons*(x: uint16): untyped =
   ## 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 =
-      when defined(android4):
-        posix.gethostbyaddr(cast[cstring](addr(myaddr)), sizeof(myaddr).cint,
-                            cint(posix.AF_INET))
-      else:
-        posix.gethostbyaddr(addr(myaddr), sizeof(myaddr).SockLen,
-                            cint(posix.AF_INET))
-    if s == nil:
-      raiseOSError(osLastError(), $hstrerror(h_errno))
-
-  result.name = $s.h_name
-  result.aliases = cstringArrayToSeq(s.h_aliases)
-  when useWinVersion:
-    result.addrtype = Domain(s.h_addrtype)
-  else:
-    if s.h_addrtype == posix.AF_INET:
-      result.addrtype = AF_INET
-    elif s.h_addrtype == posix.AF_INET6:
-      result.addrtype = AF_INET6
-    else:
-      raiseOSError(osLastError(), "unknown h_addrtype")
-  if result.addrtype == AF_INET:
-    result.addrList = @[]
-    var i = 0
-    while not isNil(s.h_addr_list[i]):
-      var inaddrPtr = cast[ptr InAddr](s.h_addr_list[i])
-      result.addrList.add($inet_ntoa(inaddrPtr[]))
-      inc(i)
-  else:
-    result.addrList = cstringArrayToSeq(s.h_addr_list)
-  result.length = int(s.h_length)
-
-proc 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, size)
-  else:
-    # Posix
-    let success = posix.gethostname(result, size)
-  if success != 0.cint:
-    raiseOSError(osLastError())
-  let x = len(cstring(result))
-  result.setLen(x)
-
 proc getSockDomain*(socket: SocketHandle): Domain =
   ## Returns the socket's domain (AF_INET or AF_INET6).
   var name: Sockaddr_in6
@@ -464,162 +349,354 @@ proc getSockDomain*(socket: SocketHandle): Domain =
   else:
     raise newException(IOError, "Unknown socket family in getSockDomain")
 
-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, addr result[0],
-                         result.len.int32) == nil:
-        raiseOSError(osLastError())
-      if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
-        result.setSlice("::ffff:".len..<addrLen)
+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:
+      var s = winlean.getservbyname(name, proto)
     else:
-      if winlean.inet_ntop(winlean.AF_INET6, addr6, 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, addr strAddress[0],
-                         strAddress.len.int32) == nil:
-        raiseOSError(osLastError())
+      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:
-      if winlean.inet_ntop(winlean.AF_INET, addr4, 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, addr strAddress[0],
-                         strAddress.len.int32) == nil:
-        raiseOSError(osLastError())
-      if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
-        strAddress.setSlice("::ffff:".len..<length)
+      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:
-      if winlean.inet_ntop(winlean.AF_INET6, addr6, 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.sin_family = uint16(ord(AF_INET))
-  else:
-    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 getsockname(socket, cast[ptr SockAddr](addr(name)),
-                 addr(namelen)) == -1'i32:
-    raiseOSError(osLastError())
-  result = Port(nativesockets.ntohs(name.sin_port))
+      var s =
+        when defined(android4):
+          posix.gethostbyaddr(cast[cstring](addr(myaddr)), sizeof(myaddr).cint,
+                              cint(posix.AF_INET))
+        else:
+          posix.gethostbyaddr(addr(myaddr), sizeof(myaddr).SockLen,
+                              cint(posix.AF_INET))
+      if s == nil:
+        raiseOSError(osLastError(), $hstrerror(h_errno))
+
+    result.name = $s.h_name
+    result.aliases = cstringArrayToSeq(s.h_aliases)
+    when useWinVersion:
+      result.addrtype = Domain(s.h_addrtype)
+    else:
+      if s.h_addrtype == posix.AF_INET:
+        result.addrtype = AF_INET
+      elif s.h_addrtype == posix.AF_INET6:
+        result.addrtype = AF_INET6
+      else:
+        raiseOSError(osLastError(), "unknown h_addrtype")
+    if result.addrtype == AF_INET:
+      result.addrList = @[]
+      var i = 0
+      while not isNil(s.h_addr_list[i]):
+        var inaddrPtr = cast[ptr InAddr](s.h_addr_list[i])
+        result.addrList.add($inet_ntoa(inaddrPtr[]))
+        inc(i)
+    else:
+      result.addrList = cstringArrayToSeq(s.h_addr_list)
+    result.length = int(s.h_length)
 
-proc 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
+  proc getHostByName*(name: string): Hostent {.tags: [ReadIOEffect].} =
+    ## This function will lookup the IP address of a hostname.
     when useWinVersion:
-      name.sin_family = uint16(ord(AF_INET))
+      var s = winlean.gethostbyname(name)
     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
+      var s = posix.gethostbyname(name)
+    if s == nil: raiseOSError(osLastError())
+    result.name = $s.h_name
+    result.aliases = cstringArrayToSeq(s.h_aliases)
     when useWinVersion:
-      name.sin6_family = uint16(ord(AF_INET6))
+      result.addrtype = Domain(s.h_addrtype)
     else:
-      name.sin6_family = TSa_Family(posix.AF_INET6)
-    var namelen = sizeof(name).SockLen
-    if getsockname(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
-      raiseOSError(osLastError())
-    # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
-    result[0] = newString(64)
-    if inet_ntop(name.sin6_family.cint,
-        addr name.sin6_addr, addr result[0][0], (result[0].len+1).int32).isNil:
+      if s.h_addrtype == posix.AF_INET:
+        result.addrtype = AF_INET
+      elif s.h_addrtype == posix.AF_INET6:
+        result.addrtype = AF_INET6
+      else:
+        raiseOSError(osLastError(), "unknown h_addrtype")
+    if result.addrtype == AF_INET:
+      result.addrList = @[]
+      var i = 0
+      while not isNil(s.h_addr_list[i]):
+        var inaddrPtr = cast[ptr InAddr](s.h_addr_list[i])
+        result.addrList.add($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, size)
+    else:
+      # Posix
+      let success = posix.gethostname(result, size)
+    if success != 0.cint:
       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:
+    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, 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, 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, addr strAddress[0],
+                          strAddress.len.int32) == nil:
+          raiseOSError(osLastError())
+      else:
+        if winlean.inet_ntop(winlean.AF_INET, addr4, 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, 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, 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.sin_family = uint16(ord(AF_INET))
     else:
       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())
-    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))
+    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 = ($inet_ntoa(name.sin_addr),
+                Port(nativesockets.ntohs(name.sin_port)))
+    of AF_INET6:
+      var name: Sockaddr_in6
+      when useWinVersion:
+        name.sin6_family = uint16(ord(AF_INET6))
+      else:
+        name.sin6_family = TSa_Family(posix.AF_INET6)
+      var namelen = sizeof(name).SockLen
+      if getsockname(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
+      result[0] = newString(64)
+      if inet_ntop(name.sin6_family.cint,
+          addr name.sin6_addr, addr result[0][0], (result[0].len+1).int32).isNil:
+        raiseOSError(osLastError())
+      setLen(result[0], result[0].cstring.len)
+      result[1] = Port(nativesockets.ntohs(name.sin6_port))
     else:
-      name.sin6_family = TSa_Family(posix.AF_INET6)
-    var namelen = sizeof(name).SockLen
-    if getpeername(socket, cast[ptr SockAddr](addr(name)),
-                   addr(namelen)) == -1'i32:
-      raiseOSError(osLastError())
-    # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
-    result[0] = newString(64)
-    if inet_ntop(name.sin6_family.cint,
-        addr name.sin6_addr, addr result[0][0], (result[0].len+1).int32).isNil:
+      raiseOSError(OSErrorCode(-1), "invalid socket family in getLocalAddr")
+
+  proc getPeerAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
+    ## Returns the socket's peer address and port number.
+    ##
+    ## Similar to POSIX's `getpeername`:idx:
+    case domain
+    of AF_INET:
+      var name: Sockaddr_in
+      when useWinVersion:
+        name.sin_family = uint16(ord(AF_INET))
+      else:
+        name.sin_family = TSa_Family(posix.AF_INET)
+      var namelen = sizeof(name).SockLen
+      if getpeername(socket, cast[ptr SockAddr](addr(name)),
+                    addr(namelen)) == -1'i32:
+        raiseOSError(osLastError())
+      result = ($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, 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())
-    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 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].} =
@@ -733,14 +810,14 @@ proc accept*(fd: SocketHandle, inheritable = defined(nimInheritHandles)): (Socke
   ## child processes.
   ##
   ## Returns (osInvalidSocket, "") if an error occurred.
-  var sockAddress: Sockaddr_in
+  var sockAddress: Sockaddr
   var addrLen = sizeof(sockAddress).SockLen
   var sock =
     when (defined(linux) or defined(bsd)) and not defined(nimdoc):
-      accept4(fd, cast[ptr SockAddr](addr(sockAddress)), addr(addrLen),
+      accept4(fd, addr(sockAddress), addr(addrLen),
               if inheritable: 0 else: SOCK_CLOEXEC)
     else:
-      accept(fd, cast[ptr SockAddr](addr(sockAddress)), addr(addrLen))
+      accept(fd, addr(sockAddress), addr(addrLen))
   when declared(setInheritable) and not (defined(linux) or defined(bsd)):
     if not setInheritable(sock, inheritable):
       close sock
@@ -748,7 +825,11 @@ proc accept*(fd: SocketHandle, inheritable = defined(nimInheritHandles)): (Socke
   if sock == osInvalidSocket:
     return (osInvalidSocket, "")
   else:
-    return (sock, $inet_ntoa(sockAddress.sin_addr))
+    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
diff --git a/lib/pure/net.nim b/lib/pure/net.nim
index 09cdc8afb..7b0ff78e7 100644
--- a/lib/pure/net.nim
+++ b/lib/pure/net.nim
@@ -85,12 +85,14 @@ runnableExamples("-r:off"):
 
 import std/private/since
 
-import nativesockets, os, strutils, times, sets, options, std/monotimes
+import nativesockets
+import os, strutils, times, sets, options, std/monotimes
 import ssl_config
 export nativesockets.Port, nativesockets.`$`, nativesockets.`==`
 export Domain, SockType, Protocol
 
 const useWinVersion = defined(windows) or defined(nimdoc)
+const useNimNetLite = defined(nimNetLite) or defined(freertos) or defined(zephyr)
 const defineSsl = defined(ssl) or defined(nimdoc)
 
 when useWinVersion:
@@ -1243,11 +1245,12 @@ proc getLocalAddr*(socket: Socket): (string, Port) =
   ## This is high-level interface for `getsockname`:idx:.
   getLocalAddr(socket.fd, socket.domain)
 
-proc getPeerAddr*(socket: Socket): (string, Port) =
-  ## Get the socket's peer address and port number.
-  ##
-  ## This is high-level interface for `getpeername`:idx:.
-  getPeerAddr(socket.fd, socket.domain)
+when not useNimNetLite:
+  proc getPeerAddr*(socket: Socket): (string, Port) =
+    ## Get the socket's peer address and port number.
+    ##
+    ## This is high-level interface for `getpeername`:idx:.
+    getPeerAddr(socket.fd, socket.domain)
 
 proc setSockOpt*(socket: Socket, opt: SOBool, value: bool,
     level = SOL_SOCKET) {.tags: [WriteIOEffect].} =
@@ -1259,7 +1262,7 @@ proc setSockOpt*(socket: Socket, opt: SOBool, value: bool,
   var valuei = cint(if value: 1 else: 0)
   setSockOptInt(socket.fd, cint(level), toCInt(opt), valuei)
 
-when defined(posix) or defined(nimdoc):
+when defined(nimdoc) or (defined(posix) and not useNimNetLite):
   proc connectUnix*(socket: Socket, path: string) =
     ## Connects to Unix socket on `path`.
     ## This only works on Unix-style systems: Mac OS X, BSD and Linux
diff --git a/lib/pure/selectors.nim b/lib/pure/selectors.nim
index 82550e09b..ec441f6da 100644
--- a/lib/pure/selectors.nim
+++ b/lib/pure/selectors.nim
@@ -323,6 +323,23 @@ else:
     # Anything higher is the time to wait in milliseconds.
     doAssert(timeout >= -1, "Cannot select with a negative value, got: " & $timeout)
 
+  when defined(linux) or defined(windows) or defined(macosx) or defined(bsd) or
+       defined(zephyr) or defined(freertos):
+    template maxDescriptors*(): int =
+      ## Returns the maximum number of active file descriptors for the current
+      ## process. This involves a system call. For now `maxDescriptors` is
+      ## supported on the following OSes: Windows, Linux, OSX, BSD.
+      when defined(windows):
+        16_700_000
+      elif defined(zephyr) or defined(freertos):
+        FD_MAX
+      else:
+        var fdLim: RLimit
+        var res = int(getrlimit(RLIMIT_NOFILE, fdLim))
+        if res >= 0:
+          res = int(fdLim.rlim_cur) - 1
+        res
+
   when defined(linux) and not defined(emscripten):
     include ioselects/ioselectors_epoll
   elif bsdPlatform:
@@ -337,5 +354,7 @@ else:
     include ioselects/ioselectors_select
   elif defined(freertos) or defined(lwip):
     include ioselects/ioselectors_select
+  elif defined(zephyr):
+    include ioselects/ioselectors_poll
   else:
     include ioselects/ioselectors_poll