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net/flow_dissector: move bpf case into __skb_flow_bpf_dissect 

This way, we can reuse it for flow dissector in BPF_PROG_TEST_RUN.

No functional changes.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Stanislav Fomichev 2019-01-28 08:53:53 -08:00 committed by Daniel Borkmann
parent d76198b0bc
commit c8aa703822
2 changed files with 59 additions and 38 deletions
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5
include/linux/skbuff.h
View File

@ -1221,6 +1221,11 @@ static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
} }
#endif #endif
struct bpf_flow_keys;
bool __skb_flow_bpf_dissect(struct bpf_prog *prog,
const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
struct bpf_flow_keys *flow_keys);
bool __skb_flow_dissect(const struct sk_buff *skb, bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector, struct flow_dissector *flow_dissector,
void *target_container, void *target_container,

92
net/core/flow_dissector.c
View File

@ -683,6 +683,46 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
} }
} }
bool __skb_flow_bpf_dissect(struct bpf_prog *prog,
const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
struct bpf_flow_keys *flow_keys)
{
struct bpf_skb_data_end cb_saved;
struct bpf_skb_data_end *cb;
u32 result;
/* Note that even though the const qualifier is discarded
* throughout the execution of the BPF program, all changes(the
* control block) are reverted after the BPF program returns.
* Therefore, __skb_flow_dissect does not alter the skb.
*/
cb = (struct bpf_skb_data_end *)skb->cb;
/* Save Control Block */
memcpy(&cb_saved, cb, sizeof(cb_saved));
memset(cb, 0, sizeof(*cb));
/* Pass parameters to the BPF program */
memset(flow_keys, 0, sizeof(*flow_keys));
cb->qdisc_cb.flow_keys = flow_keys;
flow_keys->nhoff = skb_network_offset(skb);
flow_keys->thoff = flow_keys->nhoff;
bpf_compute_data_pointers((struct sk_buff *)skb);
result = BPF_PROG_RUN(prog, skb);
/* Restore state */
memcpy(cb, &cb_saved, sizeof(cb_saved));
flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, 0, skb->len);
flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
flow_keys->nhoff, skb->len);
return result == BPF_OK;
}
/** /**
* __skb_flow_dissect - extract the flow_keys struct and return it * __skb_flow_dissect - extract the flow_keys struct and return it
* @skb: sk_buff to extract the flow from, can be NULL if the rest are specified * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
@ -714,7 +754,6 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector_key_vlan *key_vlan; struct flow_dissector_key_vlan *key_vlan;
enum flow_dissect_ret fdret; enum flow_dissect_ret fdret;
enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
struct bpf_prog *attached = NULL;
int num_hdrs = 0; int num_hdrs = 0;
u8 ip_proto = 0; u8 ip_proto = 0;
bool ret; bool ret;
@ -754,53 +793,30 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
FLOW_DISSECTOR_KEY_BASIC, FLOW_DISSECTOR_KEY_BASIC,
target_container); target_container);
rcu_read_lock();
if (skb) { if (skb) {
struct bpf_flow_keys flow_keys;
struct bpf_prog *attached = NULL;
rcu_read_lock();
if (skb->dev) if (skb->dev)
attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog);
else if (skb->sk) else if (skb->sk)
attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog);
else else
WARN_ON_ONCE(1); WARN_ON_ONCE(1);
}
if (attached) {
/* Note that even though the const qualifier is discarded
* throughout the execution of the BPF program, all changes(the
* control block) are reverted after the BPF program returns.
* Therefore, __skb_flow_dissect does not alter the skb.
*/
struct bpf_flow_keys flow_keys = {};
struct bpf_skb_data_end cb_saved;
struct bpf_skb_data_end *cb;
u32 result;
cb = (struct bpf_skb_data_end *)skb->cb; if (attached) {
ret = __skb_flow_bpf_dissect(attached, skb,
/* Save Control Block */ flow_dissector,
memcpy(&cb_saved, cb, sizeof(cb_saved)); &flow_keys);
memset(cb, 0, sizeof(cb_saved)); __skb_flow_bpf_to_target(&flow_keys, flow_dissector,
target_container);
/* Pass parameters to the BPF program */ rcu_read_unlock();
cb->qdisc_cb.flow_keys = &flow_keys; return ret;
flow_keys.nhoff = nhoff; }
flow_keys.thoff = nhoff;
bpf_compute_data_pointers((struct sk_buff *)skb);
result = BPF_PROG_RUN(attached, skb);
/* Restore state */
memcpy(cb, &cb_saved, sizeof(cb_saved));
flow_keys.nhoff = clamp_t(u16, flow_keys.nhoff, 0, skb->len);
flow_keys.thoff = clamp_t(u16, flow_keys.thoff,
flow_keys.nhoff, skb->len);
__skb_flow_bpf_to_target(&flow_keys, flow_dissector,
target_container);
rcu_read_unlock(); rcu_read_unlock();
return result == BPF_OK;
} }
rcu_read_unlock();
if (dissector_uses_key(flow_dissector, if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS)) { FLOW_DISSECTOR_KEY_ETH_ADDRS)) {