commit 4bc539a: [Project] Add preliminary version of maps expressions

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2019-05-17 18:34:14 +0100
URL: https://github.com/rspamd/rspamd/commit/4bc539a69fb8f5a44786c8f480fa2c12ebdbdb65 (HEAD -> master)

[Project] Add preliminary version of maps expressions

---
 lualib/lua_maps_expressions.lua | 161 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)

diff --git a/lualib/lua_maps_expressions.lua b/lualib/lua_maps_expressions.lua
new file mode 100644
index 000000000..495820703
--- /dev/null
+++ b/lualib/lua_maps_expressions.lua
@@ -0,0 +1,161 @@
+--[[[
+-- @module lua_maps_expressions
+-- This module contains routines to combine maps, selectors and expressions
+-- in a generic framework
+ at example
+whitelist_ip_from = {
+  rules {
+    ip {
+      selector = "ip";
+      map = "/path/to/whitelist_ip.map";
+    }
+    from {
+      selector = "from(smtp)";
+      map = "/path/to/whitelist_from.map";
+    }
+  }
+  expression = "ip & from";
+}
+--]]
+
+--[[
+Copyright (c) 2019, Vsevolod Stakhov <vsevolod at highsecure.ru>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+]]--
+
+local lua_selectors = require "lua_selectors"
+local lua_maps = require "lua_maps"
+local rspamd_expression = require "rspamd_expression"
+local rspamd_logger = require "rspamd_logger"
+local fun = require "fun"
+
+local exports = {}
+
+local function process_func(elt, task)
+  local matched = {}
+  local function process_atom(atom)
+    local rule = elt.rules[atom]
+    local res = 0
+
+    local function match_rule(val)
+      local map_match = rule.map:get_key(val)
+      if map_match then
+        res = 1.0
+        matched[rule.name] = {
+          matched = val,
+          value = map_match
+        }
+      end
+    end
+
+    local values = rule.selector(task)
+
+    if values then
+      if type(values) == 'table' then
+        for _,val in ipairs(values) do
+          if res == 0 then
+            match_rule(val)
+          end
+        end
+      else
+        match_rule(values)
+      end
+    end
+
+    return res
+  end
+
+  local res = elt.expr:process(process_atom)
+
+  if res then
+    return res,matched
+  end
+
+  return nil
+end
+
+local function create(cfg, obj, module_name)
+  if not module_name then module_name = 'lua_maps_expressions' end
+
+  if not obj or not obj.rules or not obj.expression then
+    rspamd_logger.errx(cfg, 'cannot add maps combination for module %s: required elements are missing',
+        module_name)
+    return nil
+  end
+
+  local ret = {
+    process = process_func,
+    rules = {},
+    module_name = module_name
+  }
+
+  for name,rule in pairs(obj.rules) do
+    local sel = lua_selectors.parse_selector(cfg, rule.selector)
+
+    if not sel then
+      rspamd_logger.errx(cfg, 'cannot add selector for element %s in module %s',
+          name, module_name)
+    end
+
+    local map = lua_maps.map_add_from_ucl(rule.map, rule.type or 'set',
+        obj.description or module_name)
+    if not map then
+      rspamd_logger.errx(cfg, 'cannot add map for element %s in module %s',
+          name, module_name)
+    end
+
+    if sel and map then
+      ret.rules[name] = {
+        selector = sel,
+        map = map,
+      }
+    else
+      return nil
+    end
+  end
+
+  -- Now process and parse expression
+  local function parse_atom(str)
+    local atom = table.concat(fun.totable(fun.take_while(function(c)
+      if string.find(', \t()><+!|&\n', c) then
+        return false
+      end
+      return true
+    end, fun.iter(str))), '')
+
+    if ret.rules[atom] then
+      return atom
+    end
+
+    rspamd_logger.errx(cfg, 'use of undefined element "%s" when parsing maps expression for %s',
+        atom, module_name)
+
+    return nil
+  end
+  local expr = rspamd_expression.create(obj.expression, parse_atom, rspamd_config:get_mempool())
+
+  if not expr then
+    rspamd_logger.errx(cfg, 'cannot add map expression for module %s',
+        module_name)
+    return nil
+  end
+
+  ret.expr = expr
+
+  return ret
+end
+
+exports.create = create
+
+return exports
\ No newline at end of file