globus_net_manager_tutorial(3) | globus_net_manager | globus_net_manager_tutorial(3) |
globus_net_manager_tutorial - Net Manager Implementation Tutorial
This example uses functionality from globus_common and globus_net_manager modules, so the headers for those must be included:
#include "globus_common.h" #include "globus_net_manager.h"
To implement a network manager, define a struct globus_net_manager_s
containing pointers to the functions in your code that you want invoked
during network events, and pass that to
globus_net_manager_register(). Applications which use the
Context functions or the Globus XIO Net Manager Driver will
invoke your functions as network operations occur. For this example (and I
would imagine most real implementations), the globus_net_manager_t is
statically initialized, like this:
static globus_net_manager_t globus_l_net_manager_logging = {
"logging",
globus_l_net_manager_logging_pre_listen,
globus_l_net_manager_logging_post_listen,
globus_l_net_manager_logging_end_listen,
globus_l_net_manager_logging_pre_accept,
globus_l_net_manager_logging_post_accept,
globus_l_net_manager_logging_pre_connect,
globus_l_net_manager_logging_post_connect,
globus_l_net_manager_logging_pre_close,
globus_l_net_manager_logging_post_close };
For the examples provided in this library, the globus_net_manager_s is
registered during module activation in a globus_extension module. This
method makes it easy to use network managers in a shared library
environment. This is also a good place to initialize any state that you need
to retain between calls to the network manager.
To implement this, do the following:
static int globus_l_net_manager_logging_activate(void) {
globus_hashtable_init(
&globus_l_nm_logging_logfiles,
7,
globus_hashtable_string_hash,
globus_hashtable_string_keyeq);
int rc = globus_module_activate(GLOBUS_NET_MANAGER_MODULE);
if (rc == 0)
{
rc = globus_net_manager_register(
&globus_l_net_manager_logging,
GlobusExtensionMyModule(globus_net_manager_logging));
}
return rc; } static void globus_l_logging_logfiles_destroy(void *datum) {
globus_l_nm_logging_logref_t *logref = datum;
if (logref)
{
free(logref->key);
fclose(logref->handle);
free(logref);
} } static int globus_l_net_manager_logging_deactivate(void) {
globus_hashtable_destroy_all(
&globus_l_nm_logging_logfiles,
globus_l_logging_logfiles_destroy);
int rc = globus_net_manager_unregister(&globus_l_net_manager_logging);
if (rc == 0)
{
rc = globus_module_deactivate(GLOBUS_NET_MANAGER_MODULE);
}
return rc; }
Finally, the real work of the manager is done in the functions registered in the globus_net_manager_s. For brevity, I'll just include the pre_listen function in this tutorial. This function is passed the task-id associated with the operation, the transport ('tcp', 'udp', 'udt', etc) used by the network, and whatever attributes are associated with the operation. If we wanted to modify things before they were processed by the network, we could create a modified copy of the attributes in the pre_listen function and return them via the attr_array_out parameter. In this case, we simply print out the information we've received from the network stack.
static globus_result_t globus_l_net_manager_logging_pre_listen(
struct globus_net_manager_s *manager,
const globus_net_manager_attr_t *manager_attr_array,
const char *task_id,
const char *transport,
const globus_net_manager_attr_t *attr_array,
globus_net_manager_attr_t **attr_array_out) {
FILE * logfile;
logfile = globus_l_net_manager_logging_get_logfile(manager_attr_array);
globus_l_net_manager_logging_log_header(logfile, manager, task_id, transport, "pre_listen");
globus_l_net_manager_logging_log_attrs(logfile, attr_array);
globus_l_net_manager_logging_log_footer(logfile);
return GLOBUS_SUCCESS; } /* globus_l_net_manager_logging_pre_listen() */
Tue Dec 15 2020 | Version 1.5 |