void flow_table_rem(flow_table_t *ft, struct flow_keys match) {
int index = 0;
unsigned long flags = 0;
match_stk_t *curr = NULL;
match_stk_t *last = NULL;
index = flow_keys_hash(match) % ft->size;
curr = rcu_dereference_bh(ft->table[index]);
pr_debug("FT: removing bucket entry at %d\n", index);
while(curr != NULL && !flow_key_equal(match, curr->match)) {
last = curr;
curr = rcu_dereference_bh(curr->next);
}
if(curr != NULL && flow_key_equal(match, curr->match)) {
// entry exists
ft_lock(flags);
if(curr == ft->table[index]){
// if at the beginning of bucket
rcu_assign_pointer(ft->table[index], curr->next);
} else {
// otherwise
rcu_assign_pointer(last->next, curr->next);
}
ft_unlock(flags);
// free both stk and entry
free_match_stk_entry(curr);
atomic_dec(&ft->num_flows);
}
// else entry doesn't exist
}
void ft_play(int x[2], int team, char *map, int sem_id)
{
while (1)
{
ft_lock(sem_id);
ft_putmap(map);
if (ft_alone(map, team, x, sem_id))
break ;
ft_death(map, x, sem_id, team);
ft_move(map, x, team);
ft_putmap(map);
ft_unlock(sem_id);
sleep(1);
}
}
struct stack flow_table_get( flow_table_t *ft, struct flow_keys match, routing_table_t* routing_table, u32 dst_ip) {
struct stack no_stack;
struct stack new_stk;
struct stack old_stk;
unsigned long flags = 0;
match_stk_t *curr = NULL;
match_stk_t *prev = NULL;
int index = 0;
no_stack.num_tags = -1;
index = flow_keys_hash(match) % ft->size;
curr = rcu_dereference_bh(ft->table[index]);
while(curr != NULL && !flow_key_equal(match, curr->match)) {
pr_debug("FT: active non-matching flow\n");
prev = curr;
curr = rcu_dereference_bh(curr->next);
}
// flow_table returns "no_stack" on miss
if(curr == NULL || !flow_key_equal(match, curr->match)) {
pr_debug("FT: no matching flow\n");
return no_stack;
}
// found a matching stack - check idle timeout before returning
if(flow_idle_time(curr->last_used) > IDLE_TIMEOUT){
pr_debug("FT: matched flow - timeout.. num_flows %d -> %d\n",
atomic_read(&ft->num_flows), atomic_read(&ft->num_flows) - 1);
// if idle timed-out, remove flow entry and return no_stack
new_stk = stack_dup(get_random_stack_for_dst(dst_ip, routing_table));
old_stk = curr->stk;
ft_lock(flags);
curr->stk = new_stk;
ft_unlock(flags);
stack_free(old_stk);
}
pr_debug("FT: matched flow - updating last_used\n");
// update the last_used value for successful match
curr->last_used = jiffies;
return curr->stk;
}
void flow_table_set( flow_table_t *ft, struct flow_keys match,
struct stack orig_stk ) {
unsigned long flags = 0;
int index = 0;
match_stk_t *new_match_stk = NULL;
match_stk_t *curr = NULL;
match_stk_t *prev = NULL;
match_stk_t *tmp = NULL;
match_stk_t *to_free = NULL;
// keep separate copies of stack in routing and flow tables
struct stack stk = stack_dup(orig_stk);
new_match_stk = flow_table_new_match_stk(match, stk);
if(new_match_stk == NULL){
stack_free(stk);
return;
}
index = flow_keys_hash(match) % ft->size;
pr_debug("FT: setting flow entry %d ... num_flows: %d -> %d\n", index,
atomic_read(&ft->num_flows), atomic_read(&ft->num_flows)+1);
ft_lock(flags);
curr = rcu_dereference_bh(ft->table[index]);
while(curr != NULL && !flow_key_equal(match, curr->match)) {
// ---
if(flow_idle_time(curr->last_used) > IDLE_TIMEOUT && 0){
// if idle timed-out, remove flow entry
pr_debug("FT: non-matching flow timeout remove it %d -> %d flows\n",
atomic_read(&ft->num_flows),
atomic_read(&ft->num_flows)-1);
if(prev == NULL) {
// at the beginning of bucket
tmp = curr->next;
rcu_assign_pointer(ft->table[index], tmp);
curr->next = to_free;
to_free = curr;
curr = rcu_dereference_bh(ft->table[index]);
}
else {
// otherwise
prev->next = curr->next;
curr->next = to_free;
to_free = curr;
curr = rcu_dereference_bh(prev->next);
}
atomic_dec(&ft->num_flows);
}
else {
// Else advance to next entry in bucket
pr_debug("FT: active non-matching flow\n");
prev = curr;
curr = rcu_dereference_bh(curr->next);
}
}
if(curr != NULL && flow_key_equal(match, curr->match)) {
curr->stk = stk;
free_match_stk_entry(new_match_stk);
}
else {
tmp = rcu_dereference_bh(ft->table[index]);
if(curr == tmp) {
pr_debug("FT: creating new bucket entry at %d\n", index);
new_match_stk->next = curr;
rcu_assign_pointer(ft->table[index], new_match_stk);
}
else if (curr == NULL) {
pr_debug("FT: appending bucket entry at %d\n", index);
rcu_assign_pointer(prev->next, new_match_stk);
}
else {
pr_debug("FT: inserting bucket entry at %d\n", index);
new_match_stk->next = curr;
rcu_assign_pointer(prev->next, new_match_stk);
}
atomic_inc(&ft->num_flows);
}
ft_unlock(flags);
}