feat: prepare group argument handling

src/igmpgen.c

@@ -21,14 +21,13 @@ struct igmp_extra {
     { 2, "query",  0x11, 1, "224.0.0.1", 0 },
     { 2, "report", 0x16, 1, "224.0.0.2", 1 },
     { 2, "leave",  0x17, 1, "224.0.0.2", 0 },
-
     /* Note: end of list (please keep) */
     { 0, 0, 0, 0 },
 };
 
 void usage(char *name)
 {
-    fprintf(stderr, "usage: %s -i ethdevice -t packet.version\n", name);
+    fprintf(stderr, "usage: %s -i ethdevice -g group -t packet.version\n", name);
 }
 
 int main(int argc, char **argv)
@@ -52,7 +51,7 @@ int main(int argc, char **argv)
     printf("IGMP packet generator\n\n");
 
     printf("Parsing command line...\n");
-    while((c = getopt(argc, argv, "i:t:")) != EOF)
+    while((c = getopt(argc, argv, "i:t:g:")) != EOF)
     {
         switch (c)
         {
@@ -82,6 +81,13 @@ int main(int argc, char **argv)
                     usage(argv[0]);
                     exit(1);
                 }
+                break;
+            case 'g':
+                // Group argument handling logic
+                printf("  Group = [%s]\n", optarg);
+            	igmp_group_str = optarg;
+                break;
+
                 break;
             default:
                 usage(argv[0]);