Differences

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--- cli_entry [2009/06/13 19:50] – andrei
+++ cli_entry [2009/06/13 20:31] (current) – andrei
@@ Line 5: / Line 5: @@
 == Step 1 : setting up protocol information ==
-Most protocols have a small number of configurable parameters that influence the protocol's behaviour. Naturally, we'll want to store these parameters' values somewhere. LiSA stores all such information in a shared memory structure that is protected from concurrent accesses. So the first step is to define our own structure that contains protocol-specific data. Since all we want to do is enable the protocol, our structure will only have a field called enabled. We'll create a header file called **rstp_client.h** in the **userspace/include/** folder where we'll keep CLI-interaction related information. We have to include this header in **include/shared.h** so our structure will be recognized. In this header file we add the following:
+Most protocols have a small number of configurable parameters that influence the protocol's behaviour. Naturally, we'll want to store these parameters' values somewhere. LiSA stores all such information in a shared memory structure that is protected from concurrent accesses. So the first step is to define our own structure that contains protocol-specific data. Since all we want to do is enable the protocol, our structure will only have a field called enabled. We'll create a header file called **rstp_client.h** in the **include/** folder where we'll keep CLI-interaction related information. We have to include this header in **include/shared.h** so our structure will be recognized. In this header file we add the following:
 <code c>
 struct rstp_configuration {
@@ Line 122: / Line 122: @@
 The position of the entry in the code reflects its position in the actual menu. That is, if the first entry in the subtree of config_main is the struct menu_node rstp then it will also be the first entry in the CLI menu. Notice than when one of the entries is selected then the cmd_rstp_run routine is called.
-== Step 3 : adding menu entries for enabling RSTP on a specific interface ==
+== Step 3: implementing the global RSTP enable routine ==
+The //run// field from struct menu_node represents a pointer to a function having the following signature : int (struct cli_context *, int, char **, struct menu_node **). For a detailed description see the struct menu_node definition in **cli/cli.h**. So, first thing to do is define a routine called cmp_rstp_run having this signature in the **cli/command/config_if.h** header.
+The routine's implementation will reside in **cli/command/config_if.c**. It gets the rstp_configuration data we previously defined and sets/resets the enabled field according to the given option. It then writes the configuration back in the shared mem.
+<code c>
+int cmd_rstp_run(struct cli_context *ctx, int argc, char **argv, struct menu_node **nodev)
+{
+    struct rstp_configuration rstp;
+    int enabled = 1;
+    if (!strcmp(nodev[0]->name, "no"))
+            enabled = 0;
+    shared_get_rstp(&rstp);
+    rstp.enabled = enabled;
+    shared_set_rstp(&rstp);
+    return CLI_EX_OK;
+}
+</code>
+== Step 4 : adding menu entries for enabling RSTP on a specific interface ==
 Now that we have the protocol infrastructure in place, we can add menu entries for enabling RSTP on a certain interface. We want the menu entry to be available only for the selected interface. Only after we've given the commands //conf t// and //int EthX// should the entry become available. So we have to edit the **cli/menu/config_if.c** file, because that's where interface-related commands are. To add the enable option to the menu, we add this to the mentioned file:
@@ Line 194: / Line 215: @@
 Notice that the routine called when the entries are selected is cmd_rstp_if_set. So...
-== Step 4 : implementing called routine ==
+== Step 5 : implementing the interface enable/disable routine ==
-The //run// field from struct menu_node represents a pointer to a function having the following signature : int (struct cli_context *, int, char **, struct menu_node **). For a detailed description see the struct menu_node definition in **cli/cli.h**. So, first thing to do is define a routine called cmp_rstp_if_set having this signature in the **cli/command/config_if.h** header.
+The cmd_rstp_if_set routine's job is to send a message to the daemon implementing the protocol that it wants a specific interface to be enabled/disabled. This requires an interprocess communication mechanism between the daemon and the CLI process. It involves the daemon creating a thread specifically for this task. The details are not related to the menu entries so they won't be described here.
-The routine's implementation will reside in **cli/command/config_if.c**:
-<code c>
-int cmd_rstp_if_set(struct cli_context *ctx, int argc, char **argv, struct menu_node **nodev)
-{
-    struct rstp_session *rstp;
-    struct rstp_configuration cfg;
-    struct swcli_context *uc = SWCLI_CTX(ctx);
-    int enable = 1;
-    int err;
-    shared_get_rstp(&cfg);
-    if (!cfg.enabled)
-            return 0;
-    if (!strcmp(nodev[0]->name, "no"))
-            enable = 0;
-    if (!RSTP_SESSION_OPEN(ctx, rstp)) {
-            EX_STATUS_REASON(ctx, "%s", strerror(errno));
-            return CLI_EX_REJECTED;
-    }
-    err = rstp_set_interface(rstp, uc->ifindex, enable);
-    RSTP_SESSION_CLOSE(ctx, rstp);
-    return err;
-}
-</code>