Changes ipOps.get_ips_from_range() behavior to return true first IP address

from a supplied range, not simply copying over the address used to specify
the range. Specifically in case of CIDR notation, the supplied address may
be any address in the range, such as "192.168.1.10/24". Closes #1285

nselib/ipOps.lua

@@ -445,37 +445,78 @@ get_ips_from_range = function( range )
     return nil, nil, "Error in ipOps.get_ips_from_range: Expected a range as a string."
   end
 
-  local first, last, prefix
-  if range:match( "/" ) then
-    first, prefix = range:match( "([%x%d:%.]+)/(%d+)" )
-  elseif range:match( "-" ) then
-    first, last = range:match( "([%x%d:%.]+)%s*%-%s*([%x%d:%.]+)" )
+  local ip, prefix = range:match("^%s*([%x:.]+)/(%d+)%s*$")
+  if ip then
+    return get_first_last_ip(ip, prefix)
   end
-
-  local err = {}
-  if first and ( last or prefix ) then
-    first, err[#err+1] = expand_ip( first )
-  else
+  local first, last = range:match("^%s*([%x:.]+)%s*%-%s*([%x:.]+)%s*$")
+  if not first then
     return nil, nil, "Error in ipOps.get_ips_from_range: The range supplied could not be interpreted."
   end
-  if last then
-    last, err[#err+1] = expand_ip( last )
-  elseif first and prefix then
-    last, err[#err+1] = get_last_ip( first, prefix )
-  end
 
-  if first and last then
-    if ( first:match( ":" ) and not last:match( ":" ) ) or ( not first:match( ":" ) and last:match( ":" ) ) then
-      return nil, nil, "Error in ipOps.get_ips_from_range: First IP address is of a different address family to last IP address."
+  local err
+  first, err = expand_ip(first)
+  if not err then
+    last, err = expand_ip(last)
+  end
+  if not err then
+    local af = function (ip) return ip:find(":") and 6 or 4 end
+    if af(first) ~= af(last) then
+      err = "Error in ipOps.get_ips_from_range: First IP address is of a different address family to last IP address."
     end
-    return first, last
-  else
-    return nil, nil, table.concat( err, " " )
   end
-
+  if err then
+      return nil, nil, err
+  end
+  return first, last
 end
 
+---
+-- Calculates the first and last IP addresses of a range of addresses,
+-- given an IP address in the range and a prefix length for that range
+-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
+--           is permitted.
+-- @param prefix Number or a string representing a decimal number corresponding
+--               to a prefix length.
+-- @usage
+-- first, last = ipOps.get_first_last_ip( "192.0.0.0", 26)
+-- @return String representing the first IP address of the range denoted by
+--         the supplied parameters (or <code>nil</code> in case of an error).
+-- @return String representing the last IP address of the range denoted by
+--         the supplied parameters (or <code>nil</code> in case of an error).
+-- @return String error message in case of an error.
+get_first_last_ip = function(ip, prefix)
+  local err
+  ip, err = ip_to_bin(ip)
+  if err then return nil, nil, err end
 
+  prefix = tonumber(prefix)
+  if not prefix or prefix ~= math.floor(prefix) or prefix < 0 or prefix > #ip then
+    return nil, nil, "Error in ipOps.get_first_last_ip: Invalid prefix."
+  end
+
+  local net = ip:sub(1, prefix)
+  local first = bin_to_ip(net .. ("0"):rep(#ip - prefix))
+  local last  = bin_to_ip(net .. ("1"):rep(#ip - prefix))
+  return first, last
+end
+
+---
+-- Calculates the first IP address of a range of addresses given an IP address in
+-- the range and prefix length for that range.
+-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
+--           is permitted.
+-- @param prefix Number or a string representing a decimal number corresponding
+--               to a prefix length.
+-- @usage
+-- first = ipOps.get_first_ip( "192.0.0.0", 26 )
+-- @return String representing the first IP address of the range denoted by the
+--         supplied parameters (or <code>nil</code> in case of an error).
+-- @return String error message in case of an error.
+get_first_ip = function(ip, prefix)
+  local first, last, err = get_first_last_ip(ip, prefix)
+  return first, err
+end
 
 ---
 -- Calculates the last IP address of a range of addresses given an IP address in
@@ -489,23 +530,9 @@ end
 -- @return String representing the last IP address of the range denoted by the
 --         supplied parameters (or <code>nil</code> in case of an error).
 -- @return String error message in case of an error.
-get_last_ip = function( ip, prefix )
-
-  local first, err = ip_to_bin( ip )
-  if err then return nil, err end
-
-  prefix = tonumber( prefix )
-  if not prefix or ( prefix < 0 ) or ( prefix > # first  ) then
-    return nil, "Error in ipOps.get_last_ip: Invalid prefix length."
-  end
-
-  local hostbits = string.sub( first, prefix + 1 )
-  hostbits = string.gsub( hostbits, "0", "1" )
-  local last = string.sub( first, 1, prefix ) .. hostbits
-  last, err = bin_to_ip( last )
-  if err then return nil, err end
-  return last
-
+get_last_ip = function(ip, prefix)
+  local first, last, err = get_first_last_ip(ip, prefix)
+  return last, err
 end
 
 ---
@@ -807,8 +834,12 @@ do
   for _, op in ipairs({
     {"192.168.13.1", "192/8", unittest.is_true, "IPv4 CIDR"},
     {"193.168.13.1", "192/8", unittest.is_false, "IPv4 CIDR"},
+    {"192.168.13.0", "192.168.13.128/24", unittest.is_true, "IPv4 CIDR"},
+    {"193.168.13.0", "192.168.13.128/24", unittest.is_false, "IPv4 CIDR"},
     {"2001:db8::9", "2001:db8/32", unittest.is_true, "IPv6 CIDR"},
     {"2001:db7::9", "2001:db8/32", unittest.is_false, "IPv6 CIDR"},
+    {"2001:db8::9", "2001:db8::1:0/32", unittest.is_true, "IPv6 CIDR"},
+    {"2001:db7::9", "2001:db8::1:0/32", unittest.is_false, "IPv6 CIDR"},
     {"192.168.13.1", "192.168.10.33-192.168.80.80", unittest.is_true, "IPv4 range"},
     {"193.168.13.1", "192.168.1.1 - 192.168.5.0", unittest.is_false, "IPv4 range"},
     {"2001:db8::9", "2001:db8::1-2001:db8:1::1", unittest.is_true, "IPv6 range"},