/**
* mul_route_select_single_and_purge_list -
* @route_list : A route list
* @rt_select_hint : The route number to select
*
* Grabs a route from route list as denoted by rt_select_hint and return to caller
* If rt_select_hint > number of routes in route list it will return NULL
*/
static GSList *
mul_route_select_single_and_purge_list(rt_list_t *route_list, size_t rt_select_hint)
{
GSList *route = NULL;
rt_list_t *tmp;
size_t rt_count = 0;
if (!route_list) {
return route;
}
while (route_list) {
tmp = route_list;
route_list = route_list->next;
if (rt_count++ == rt_select_hint) {
route = tmp->route;
} else {
mul_destroy_route(tmp->route);
}
free(tmp);
}
return route;
}
/**
* mul_route_list_free -
*
* Free a route list
*/
static void
mul_route_list_free(rt_list_t *path_head, bool free_route)
{
rt_list_t *cur_path = path_head, *prev_path = NULL;
while (cur_path) {
prev_path = cur_path;
cur_path = cur_path->next;
if (free_route) {
mul_destroy_route(prev_path->route);
}
free(prev_path);
}
}
/**
* @name fab_route_get
*
* @brief Get a fabric route
*/
GSList *
fab_route_get(void *rt_service, int src_sw, int dst_sw,
fab_route_t *froute)
{
GSList *route = NULL;
if (!fab_ctx->use_ecmp || !froute) {
if (!(route = mul_route_get(rt_service, src_sw, dst_sw))) {
return NULL;
}
} else {
if (!(route = mul_route_get_mp(rt_service, src_sw, dst_sw,
froute, fab_mp_select))) {
return NULL;
}
}
if (!g_slist_find_custom(route, froute, (GCompareFunc)fab_route_elem_valid)) {
mul_destroy_route(route);
return NULL;
}
return route;
}
/**
* mul_route_apsp_get_mp_sp -
*
* Get shortest path between src_sw and dest_sw. If multiple paths exists
* it will select a path based of user provided mp_select function or the
* first avaialbe route if mp_select is not provided
*/
static GSList *
mul_route_apsp_get_mp_sp(void *rt_service, int src_sw, int dest_sw, void *u_arg,
size_t (*mp_select)(void *u_arg, size_t max_routes))
{
unsigned int lock, max_retries = 0;
rt_apsp_t *rt_apsp_info = rt_service;
GSList *route = NULL;
rt_list_t *route_list = NULL;
size_t mp_rt_hint = 0, num_mp_routes = 0;
lweight_pair_t last_hop = { NEIGH_NO_LINK, NEIGH_NO_LINK,
NEIGH_NO_PATH, false };
if (src_sw == dest_sw) {
goto route_same_node;
}
retry:
if (max_retries++ >= RT_MAX_GET_RETRIES) {
c_log_err("Too much writer contention or service died");
return NULL;
}
lock = c_seq_rd_lock(&rt_apsp_info->state_info->lock);
if (!rt_apsp_converged(rt_apsp_info)) {
if (c_seq_rd_unlock(&rt_apsp_info->state_info->lock,
lock)) {
goto retry;
}
c_log_err("%s: Routes not yet converged", FN);
return NULL;
}
if (rt_apsp_get_weight(rt_apsp_info, src_sw, dest_sw) == NEIGH_NO_PATH) {
if (c_seq_rd_unlock(&rt_apsp_info->state_info->lock,
lock)) {
goto retry;
}
c_log_err("%s: Not a neigbour (%d:%d) %d", FN, src_sw, dest_sw,
rt_apsp_get_weight(rt_apsp_info, src_sw, dest_sw));
return NULL;
}
route_list = mul_route_apsp_get_subp(rt_apsp_info, src_sw, dest_sw);
if (mp_select) {
num_mp_routes = mul_route_list_size(route_list);
mp_rt_hint = mp_select(u_arg, num_mp_routes);
if (mp_rt_hint >= num_mp_routes) {
/* Silently ignore any user advice on multi-path selection */
mp_rt_hint = 0;
}
}
route = mul_route_select_single_and_purge_list(route_list, mp_rt_hint);
if (c_seq_rd_unlock(&rt_apsp_info->state_info->lock, lock)) {
mul_destroy_route(route);
goto retry;
}
route_same_node:
add_route_path_elem(&route, dest_sw, &last_hop, true);
mul_route_prep_out(route);
return route;
}
/**
* tr_destroy_route -
*
* Destroy route. Utility wrapper over mul_destroy_route()
*/
void
tr_destroy_route(GSList *route)
{
return mul_destroy_route(route);
}
