diff options
| -rw-r--r-- | include/linux/skbuff.h | 5 | ||||
| -rw-r--r-- | net/core/flow_dissector.c | 92 |
2 files changed, 59 insertions, 38 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 93f56fddd92a..be762fc34ff3 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1221,6 +1221,11 @@ static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) } #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, struct flow_dissector *flow_dissector, void *target_container, diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 9f2840510e63..bb1a54747d64 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -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: 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; enum flow_dissect_ret fdret; enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; - struct bpf_prog *attached = NULL; int num_hdrs = 0; u8 ip_proto = 0; bool ret; @@ -754,53 +793,30 @@ bool __skb_flow_dissect(const struct sk_buff *skb, FLOW_DISSECTOR_KEY_BASIC, target_container); - rcu_read_lock(); if (skb) { + struct bpf_flow_keys flow_keys; + struct bpf_prog *attached = NULL; + + rcu_read_lock(); + if (skb->dev) attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); else if (skb->sk) attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); else 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; - - /* Save Control Block */ - memcpy(&cb_saved, cb, sizeof(cb_saved)); - memset(cb, 0, sizeof(cb_saved)); - /* Pass parameters to the BPF program */ - cb->qdisc_cb.flow_keys = &flow_keys; - 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); + if (attached) { + ret = __skb_flow_bpf_dissect(attached, skb, + flow_dissector, + &flow_keys); + __skb_flow_bpf_to_target(&flow_keys, flow_dissector, + target_container); + rcu_read_unlock(); + return ret; + } rcu_read_unlock(); - return result == BPF_OK; } - rcu_read_unlock(); if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ETH_ADDRS)) { |