feat(hash): add support hmac

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

CMakeLists.txt

@@ -192,6 +192,11 @@ install(
     DESTINATION ${LUA_INSTALL_PREFIX}/eco/hash
 )
 
+install(
+    FILES hmac.lua
+    DESTINATION ${LUA_INSTALL_PREFIX}/eco/hash
+)
+
 install(
     FILES time.lua sys.lua file.lua dns.lua socket.lua packet.lua mqtt.lua
         websocket.lua sync.lua channel.lua nl.lua genl.lua ip.lua nl80211.lua

examples/hash/hmac.lua

@@ -0,0 +1,17 @@
+#!/usr/bin/env eco
+
+local sha256 = require 'eco.hash.sha256'
+local hmac = require 'eco.hash.hmac'
+local hex = require 'eco.encoding.hex'
+
+-- also, you can use other hash modules, such as sha1, md5.
+local ctx = hmac.new(sha256, 'key')
+
+ctx:update('12')
+ctx:update('34')
+
+local hash = ctx:final()
+print(hex.encode(hash))
+
+hash = hmac.sum(sha256, 'key', '1234')
+print(hex.encode(hash))

hmac.lua

@@ -0,0 +1,65 @@
+-- SPDX-License-Identifier: MIT
+-- Author: Jianhui Zhao <zhaojh329@gmail.com>
+
+local M = {}
+
+local blocksize = 64
+
+local methods = {}
+
+function methods:update(data)
+    assert(type(data) == 'string', 'expecting data to be a string')
+
+    self.ctx:update(data)
+end
+
+function methods:final()
+    return self.hash.sum(self.key .. self.ctx:final())
+end
+
+local metatable = {
+    __index = methods
+}
+
+function M.new(hash, key)
+    local mtname = hash and hash.mtname
+
+    assert(mtname == 'eco{md5}'
+        or mtname == 'eco{sha1}'
+        or mtname == 'eco{sha256}',
+        'expecting hash to be a hash module')
+
+    assert(type(key) == 'string', 'expecting key to be a string')
+
+    if #key > blocksize then
+        key = hash.sum(key)
+    end
+
+    local key_xord_with_0x36 = key:gsub('.', function(c)
+        return string.char(c:byte() ~ 0x36)
+    end) .. string.rep(string.char(0x36), blocksize - #key)
+
+    local key_xord_with_0x5c = key:gsub('.', function(c)
+        return string.char(c:byte() ~ 0x5c)
+    end) .. string.rep(string.char(0x5c), blocksize - #key)
+
+    local ctx = hash.new()
+
+    ctx:update(key_xord_with_0x36)
+
+    return setmetatable({
+        ctx = ctx,
+        hash = hash,
+        key = key_xord_with_0x5c
+    }, metatable)
+end
+
+function M.sum(hash, key, data)
+    local ctx = M.new(hash, key)
+
+    ctx:update(data)
+
+    return ctx:final()
+end
+
+return M

md5.c

@@ -330,6 +330,9 @@ int luaopen_eco_hash_md5(lua_State *L)
 {
     lua_newtable(L);
 
+    lua_pushstring(L, ECO_MD5_MT);
+    lua_setfield(L, -2, "mtname");
+
     lua_pushcfunction(L, lua_md5_sum);
     lua_setfield(L, -2, "sum");
 

sha1.c

@@ -272,6 +272,9 @@ int luaopen_eco_hash_sha1(lua_State *L)
 {
     lua_newtable(L);
 
+    lua_pushstring(L, ECO_SHA1_MT);
+    lua_setfield(L, -2, "mtname");
+
     lua_pushcfunction(L, lua_sha1_sum);
     lua_setfield(L, -2, "sum");
 

sha256.c

@@ -220,6 +220,9 @@ int luaopen_eco_hash_sha256(lua_State *L)
 {
     lua_newtable(L);
 
+    lua_pushstring(L, ECO_SHA256_MT);
+    lua_setfield(L, -2, "mtname");
+
     lua_pushcfunction(L, lua_sha256_sum);
     lua_setfield(L, -2, "sum");