ncd: modules: add arithmetic

blog_channels.txt

@@ -113,3 +113,4 @@ ncd_request 4
 ncd_sys_request_client 4
 ncd_exit 4
 ncd_getargs 4
+ncd_arithmetic 4

generated/blog_channel_ncd_arithmetic.h

@@ -0,0 +1,4 @@
+#ifdef BLOG_CURRENT_CHANNEL
+#undef BLOG_CURRENT_CHANNEL
+#endif
+#define BLOG_CURRENT_CHANNEL BLOG_CHANNEL_ncd_arithmetic

generated/blog_channels_defines.h

@@ -113,4 +113,5 @@
 #define BLOG_CHANNEL_ncd_sys_request_client 112
 #define BLOG_CHANNEL_ncd_exit 113
 #define BLOG_CHANNEL_ncd_getargs 114
-#define BLOG_NUM_CHANNELS 115
+#define BLOG_CHANNEL_ncd_arithmetic 115
+#define BLOG_NUM_CHANNELS 116

generated/blog_channels_list.h

@@ -113,3 +113,4 @@
 {.name = "ncd_sys_request_client", .loglevel = 4},
 {.name = "ncd_exit", .loglevel = 4},
 {.name = "ncd_getargs", .loglevel = 4},
+{.name = "ncd_arithmetic", .loglevel = 4},

ncd/CMakeLists.txt

@@ -105,6 +105,7 @@ add_executable(badvpn-ncd
     modules/sys_request_client.c
     modules/exit.c
     modules/getargs.c
+    modules/arithmetic.c
     ${NCD_ADDITIONAL_SOURCES}
 )
 target_link_libraries(badvpn-ncd system flow flowextra dhcpclient arpprobe ncdconfig ncdvalue udevmonitor ncdinterfacemonitor ncdrequest)

ncd/modules/arithmetic.c

@@ -0,0 +1,346 @@
+/**
+ * @file arithmetic.c
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the
+ *    names of its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * @section DESCRIPTION
+ * 
+ * Arithmetic functions for unsigned integers.
+ * 
+ * Synopsis:
+ *   num_lesser(string n1, string n2)
+ *   num_greater(string n1, string n2)
+ *   num_lesser_equal(string n1, string n2)
+ *   num_greater_equal(string n1, string n2)
+ *   num_equal(string n1, string n2)
+ * 
+ * Variables:
+ *   (empty) - "true" or "false", reflecting the value of the relation in question
+ * 
+ * Description:
+ *   These statements perform arithmetic comparisons. The operands passed must be
+ *   non-negative decimal integers representable in a uintmax_t. Otherwise, an error
+ *   is triggered.
+ * 
+ * Synopsis:
+ *   num_add(string n1, string n2)
+ *   num_subtract(string n1, string n2)
+ *   num_multiply(string n1, string n2)
+ *   num_divide(string n1, string n2)
+ *   num_modulo(string n1, string n2)
+ * 
+ * Description:
+ *   These statements perform arithmetic operations. The operands passed must be
+ *   non-negative decimal integers representable in a uintmax_t, and the result must
+ *   also be representable and non-negative. For divide and modulo, n2 must be non-zero.
+ *   If any of these restrictions is violated, an error is triggered.
+ * 
+ * Variables:
+ *   (empty) - the result of the operation as a string representing a decimal number
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+#include <limits.h>
+
+#include <misc/parse_number.h>
+#include <ncd/NCDModule.h>
+
+#include <generated/blog_channel_ncd_arithmetic.h>
+
+#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)
+
+struct instance {
+    NCDModuleInst *i;
+    char value[25];
+};
+
+typedef int (*compute_func) (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str);
+
+static int compute_lesser (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    strcpy(out_str, (n1 < n2) ? "true" : "false");
+    return 1;
+}
+
+static int compute_greater (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    strcpy(out_str, (n1 > n2) ? "true" : "false");
+    return 1;
+}
+
+static int compute_lesser_equal (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    strcpy(out_str, (n1 <= n2) ? "true" : "false");
+    return 1;
+}
+
+static int compute_greater_equal (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    strcpy(out_str, (n1 >= n2) ? "true" : "false");
+    return 1;
+}
+
+static int compute_equal (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    strcpy(out_str, (n1 == n2) ? "true" : "false");
+    return 1;
+}
+
+static int compute_add (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    if (n1 > UINTMAX_MAX - n2) {
+        ModuleLog(i, BLOG_ERROR, "addition overflow");
+        return 0;
+    }
+    uintmax_t r = n1 + n2;
+    sprintf(out_str, "%"PRIuMAX, r);
+    return 1;
+}
+
+static int compute_subtract (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    if (n1 < n2) {
+        ModuleLog(i, BLOG_ERROR, "subtraction underflow");
+        return 0;
+    }
+    uintmax_t r = n1 - n2;
+    sprintf(out_str, "%"PRIuMAX, r);
+    return 1;
+}
+
+static int compute_multiply (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    if (n1 > UINTMAX_MAX / n2) {
+        ModuleLog(i, BLOG_ERROR, "multiplication overflow");
+        return 0;
+    }
+    uintmax_t r = n1 * n2;
+    sprintf(out_str, "%"PRIuMAX, r);
+    return 1;
+}
+
+static int compute_divide (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    if (n2 == 0) {
+        ModuleLog(i, BLOG_ERROR, "division quotient is zero");
+        return 0;
+    }
+    uintmax_t r = n1 / n2;
+    sprintf(out_str, "%"PRIuMAX, r);
+    return 1;
+}
+
+static int compute_modulo (NCDModuleInst *i, uintmax_t n1, uintmax_t n2, char *out_str)
+{
+    if (n2 == 0) {
+        ModuleLog(i, BLOG_ERROR, "modulo modulus is zero");
+        return 0;
+    }
+    uintmax_t r = n1 % n2;
+    sprintf(out_str, "%"PRIuMAX, r);
+    return 1;
+}
+
+static void new_templ (NCDModuleInst *i, compute_func cfunc)
+{
+    struct instance *o = malloc(sizeof(*o));
+    if (!o) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong type");
+        goto fail0;
+    }
+    o->i = i;
+    NCDModuleInst_Backend_SetUser(i, o);
+    
+    NCDValue *n1_arg;
+    NCDValue *n2_arg;
+    if (!NCDValue_ListRead(i->args, 2, &n1_arg, &n2_arg)) {
+        ModuleLog(i, BLOG_ERROR, "wrong arity");
+        goto fail1;
+    }
+    if (NCDValue_Type(n1_arg) != NCDVALUE_STRING || NCDValue_Type(n2_arg) != NCDVALUE_STRING) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong type");
+        goto fail1;
+    }
+    
+    uintmax_t n1;
+    uintmax_t n2;
+    if (!parse_unsigned_integer(NCDValue_StringValue(n1_arg), &n1) || !parse_unsigned_integer(NCDValue_StringValue(n2_arg), &n2)) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong value");
+        goto fail1;
+    }
+    
+    if (!cfunc(i, n1, n2, o->value)) {
+        goto fail1;
+    }
+    
+    NCDModuleInst_Backend_Up(i);
+    return;
+    
+fail1:
+    free(o);
+fail0:
+    NCDModuleInst_Backend_SetError(i);
+    NCDModuleInst_Backend_Dead(i);
+}
+
+static void func_die (void *vo)
+{
+    struct instance *o = vo;
+    NCDModuleInst *i = o->i;
+    
+    // free instance
+    free(o);
+    
+    NCDModuleInst_Backend_Dead(i);
+}
+
+static int func_getvar (void *vo, const char *name, NCDValue *out_value)
+{
+    struct instance *o = vo;
+    
+    if (!strcmp(name, "")) {
+        if (!NCDValue_InitString(out_value, o->value)) {
+            ModuleLog(o->i, BLOG_ERROR, "NCDValue_InitString failed");
+            return 0;
+        }
+        return 1;
+    }
+    
+    return 0;
+}
+
+static void func_new_lesser (NCDModuleInst *i)
+{
+    new_templ(i, compute_lesser);
+}
+
+static void func_new_greater (NCDModuleInst *i)
+{
+    new_templ(i, compute_greater);
+}
+
+static void func_new_lesser_equal (NCDModuleInst *i)
+{
+    new_templ(i, compute_lesser_equal);
+}
+
+static void func_new_greater_equal (NCDModuleInst *i)
+{
+    new_templ(i, compute_greater_equal);
+}
+
+static void func_new_equal (NCDModuleInst *i)
+{
+    new_templ(i, compute_equal);
+}
+
+static void func_new_add (NCDModuleInst *i)
+{
+    new_templ(i, compute_add);
+}
+
+static void func_new_subtract (NCDModuleInst *i)
+{
+    new_templ(i, compute_subtract);
+}
+
+static void func_new_multiply (NCDModuleInst *i)
+{
+    new_templ(i, compute_multiply);
+}
+
+static void func_new_divide (NCDModuleInst *i)
+{
+    new_templ(i, compute_divide);
+}
+
+static void func_new_modulo (NCDModuleInst *i)
+{
+    new_templ(i, compute_modulo);
+}
+
+static const struct NCDModule modules[] = {
+    {
+        .type = "num_lesser",
+        .func_new = func_new_lesser,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_greater",
+        .func_new = func_new_greater,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_lesser_equal",
+        .func_new = func_new_lesser_equal,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_greater_equal",
+        .func_new = func_new_greater_equal,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_equal",
+        .func_new = func_new_equal,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_add",
+        .func_new = func_new_add,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_subtract",
+        .func_new = func_new_subtract,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_multiply",
+        .func_new = func_new_multiply,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_divide",
+        .func_new = func_new_divide,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "num_modulo",
+        .func_new = func_new_modulo,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = NULL
+    }
+};
+
+const struct NCDModuleGroup ncdmodule_arithmetic = {
+    .modules = modules
+};

ncd/modules/modules.h

@@ -94,6 +94,7 @@ extern const struct NCDModuleGroup ncdmodule_net_ipv6_wait_dynamic_addr;
 extern const struct NCDModuleGroup ncdmodule_sys_request_client;
 extern const struct NCDModuleGroup ncdmodule_exit;
 extern const struct NCDModuleGroup ncdmodule_getargs;
+extern const struct NCDModuleGroup ncdmodule_arithmetic;
 
 static const struct NCDModuleGroup *ncd_modules[] = {
     &ncdmodule_var,
@@ -156,6 +157,7 @@ static const struct NCDModuleGroup *ncd_modules[] = {
     &ncdmodule_sys_request_client,
     &ncdmodule_exit,
     &ncdmodule_getargs,
+    &ncdmodule_arithmetic,
     NULL
 };