interfaces-plugin: implement IPv6 address prefix-length change callback

src/interfaces/src/plugin/api/interfaces/interface/ipv6/address/change.c

@@ -19,23 +19,113 @@ int interfaces_interface_ipv6_address_change_prefix_length_init(void* priv)
 int interfaces_interface_ipv6_address_change_prefix_length(void* priv, sr_session_ctx_t* session, const srpc_change_ctx_t* change_ctx)
 {
     int error = 0;
+    void* error_ptr = NULL;
+
+    // strings and buffers
     const char* node_name = LYD_NAME(change_ctx->node);
     const char* node_value = lyd_get_value(change_ctx->node);
+    char path_buffer[PATH_MAX] = { 0 };
+    char interface_name_buffer[100] = { 0 };
+    char ip_buffer[100] = { 0 };
+    char address_buffer[100] = { 0 };
+    char old_address_buffer[100] = { 0 };
+
+    // app context
+    interfaces_ctx_t* ctx = priv;
+
+    // mod changes context
+    interfaces_mod_changes_ctx_t* mod_ctx = &ctx->mod_ctx;
+
+    // libnl
+    struct rtnl_addr* request_addr = NULL;
+    struct rtnl_addr* delete_addr = NULL;
+    struct rtnl_link* current_link = NULL;
+    struct nl_addr* local_addr = NULL;
+    struct nl_addr* old_local_addr = NULL;
 
     SRPLG_LOG_INF(PLUGIN_NAME, "Node Name: %s; Previous Value: %s, Value: %s; Operation: %d", node_name, change_ctx->previous_value, node_value, change_ctx->operation);
 
+    // get node path
+    SRPC_SAFE_CALL_PTR(error_ptr, lyd_path(change_ctx->node, LYD_PATH_STD, path_buffer, sizeof(path_buffer)), error_out);
+
+    // get interface name
+    SRPC_SAFE_CALL_ERR(error, srpc_extract_xpath_key_value(path_buffer, "interface", "name", interface_name_buffer, sizeof(interface_name_buffer)), error_out);
+
+    // get IP
+    SRPC_SAFE_CALL_ERR(error, srpc_extract_xpath_key_value(path_buffer, "address", "ip", ip_buffer, sizeof(ip_buffer)), error_out);
+
+    SRPLG_LOG_INF(PLUGIN_NAME, "Node Path: %s; Interface Name: %s; Address IP: %s", path_buffer, interface_name_buffer, ip_buffer);
+
+    // get link
+    SRPC_SAFE_CALL_PTR(current_link, rtnl_link_get_by_name(mod_ctx->nl_ctx.link_cache, interface_name_buffer), error_out);
+
     switch (change_ctx->operation) {
     case SR_OP_CREATED:
+        // this change case should be handled only when creating the whole address in the IP callback
+        // no need to process created change
         break;
     case SR_OP_MODIFIED:
+        // change prefix length
+        request_addr = rtnl_addr_alloc();
+        delete_addr = rtnl_addr_alloc();
+
+        // get full address
+        SRPC_SAFE_CALL_ERR_COND(error, error < 0, snprintf(address_buffer, sizeof(address_buffer), "%s/%s", ip_buffer, node_value), error_out);
+        SRPC_SAFE_CALL_ERR_COND(error, error < 0, snprintf(old_address_buffer, sizeof(old_address_buffer), "%s/%s", ip_buffer, change_ctx->previous_value), error_out);
+
+        // parse local address
+        SRPC_SAFE_CALL_ERR(error, nl_addr_parse(address_buffer, AF_INET6, &local_addr), error_out);
+        SRPC_SAFE_CALL_ERR(error, nl_addr_parse(old_address_buffer, AF_INET6, &old_local_addr), error_out);
+
+        // set to route address
+        SRPC_SAFE_CALL_ERR(error, rtnl_addr_set_local(request_addr, local_addr), error_out);
+        SRPC_SAFE_CALL_ERR(error, rtnl_addr_set_local(delete_addr, old_local_addr), error_out);
+
+        // set interface
+        rtnl_addr_set_ifindex(request_addr, rtnl_link_get_ifindex(current_link));
+        rtnl_addr_set_ifindex(delete_addr, rtnl_link_get_ifindex(current_link));
+
+        // delete old address
+        SRPC_SAFE_CALL_ERR(error, rtnl_addr_delete(mod_ctx->nl_ctx.socket, delete_addr, 0), error_out);
+
+        // add new address
+        SRPC_SAFE_CALL_ERR(error, rtnl_addr_add(mod_ctx->nl_ctx.socket, request_addr, 0), error_out);
+
         break;
     case SR_OP_DELETED:
+        // prefix is needed to find the appropriate address
+        // should be processed when IP deleted
         break;
     case SR_OP_MOVED:
         break;
     }
 
-    return -1;
+    goto out;
+
+error_out:
+    if (error < 0) {
+        SRPLG_LOG_INF(PLUGIN_NAME, "nl_geterror(): %s", nl_geterror(error));
+    }
+    error = -1;
+
+out:
+    if (request_addr) {
+        rtnl_addr_put(request_addr);
+    }
+
+    if (delete_addr) {
+        rtnl_addr_put(delete_addr);
+    }
+
+    if (old_local_addr) {
+        nl_addr_put(old_local_addr);
+    }
+
+    if (local_addr) {
+        nl_addr_put(local_addr);
+    }
+
+    return error;
 }
 
 void interfaces_interface_ipv6_address_change_prefix_length_free(void* priv)