static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
struct tcf_result *res)
{
bool at_ingress = skb_at_tc_ingress(skb);
struct tcf_bpf *prog = to_bpf(act);
struct bpf_prog *filter;
int action, filter_res;
tcf_lastuse_update(&prog->tcf_tm);
bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
rcu_read_lock();
filter = rcu_dereference(prog->filter);
if (at_ingress) {
__skb_push(skb, skb->mac_len);
bpf_compute_data_end(skb);
filter_res = BPF_PROG_RUN(filter, skb);
__skb_pull(skb, skb->mac_len);
} else {
bpf_compute_data_end(skb);
filter_res = BPF_PROG_RUN(filter, skb);
}
rcu_read_unlock();
/* A BPF program may overwrite the default action opcode.
* Similarly as in cls_bpf, if filter_res == -1 we use the
* default action specified from tc.
*
* In case a different well-known TC_ACT opcode has been
* returned, it will overwrite the default one.
*
* For everything else that is unkown, TC_ACT_UNSPEC is
* returned.
*/
switch (filter_res) {
case TC_ACT_PIPE:
case TC_ACT_RECLASSIFY:
case TC_ACT_OK:
case TC_ACT_REDIRECT:
action = filter_res;
break;
case TC_ACT_SHOT:
action = filter_res;
qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats));
break;
case TC_ACT_UNSPEC:
action = prog->tcf_action;
break;
default:
action = TC_ACT_UNSPEC;
break;
}
return action;
}
static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_sample *s = to_sample(a);
struct psample_group *psample_group;
int retval;
int size;
int iif;
int oif;
tcf_lastuse_update(&s->tcf_tm);
bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
retval = READ_ONCE(s->tcf_action);
rcu_read_lock();
psample_group = rcu_dereference(s->psample_group);
/* randomly sample packets according to rate */
if (psample_group && (prandom_u32() % s->rate == 0)) {
if (!skb_at_tc_ingress(skb)) {
iif = skb->skb_iif;
oif = skb->dev->ifindex;
} else {
iif = skb->dev->ifindex;
oif = 0;
}
/* on ingress, the mac header gets popped, so push it back */
if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
skb_push(skb, skb->mac_len);
size = s->truncate ? s->trunc_size : skb->len;
psample_sample_packet(psample_group, skb, size, iif, oif,
s->rate);
if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
skb_pull(skb, skb->mac_len);
}
rcu_read_unlock();
return retval;
}
