net: introduce rx_handler results and logic around that

This patch allows rx_handlers to better signalize what to do next to
it's caller. That makes skb->deliver_no_wcard no longer needed.

kernel-doc for rx_handler_result is taken from Nicolas' patch.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Reviewed-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Pirko 2011-03-12 03:14:39 +00:00 committed by David S. Miller
parent 2d7011ca79
commit 8a4eb5734e
8 changed files with 98 additions and 39 deletions

View file

@ -1480,20 +1480,23 @@ static bool bond_should_deliver_exact_match(struct sk_buff *skb,
return false;
}
static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
struct slave *slave;
struct net_device *bond_dev;
struct bonding *bond;
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
return NULL;
slave = bond_slave_get_rcu(skb->dev);
bond_dev = ACCESS_ONCE(slave->dev->master);
if (unlikely(!bond_dev))
return skb;
return RX_HANDLER_PASS;
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
return RX_HANDLER_CONSUMED;
*pskb = skb;
bond = netdev_priv(bond_dev);
@ -1501,8 +1504,7 @@ static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
slave->dev->last_rx = jiffies;
if (bond_should_deliver_exact_match(skb, slave, bond)) {
skb->deliver_no_wcard = 1;
return skb;
return RX_HANDLER_EXACT;
}
skb->dev = bond_dev;
@ -1514,12 +1516,12 @@ static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
if (unlikely(skb_cow_head(skb,
skb->data - skb_mac_header(skb)))) {
kfree_skb(skb);
return NULL;
return RX_HANDLER_CONSUMED;
}
memcpy(eth_hdr(skb)->h_dest, bond_dev->dev_addr, ETH_ALEN);
}
return skb;
return RX_HANDLER_ANOTHER;
}
/* enslave device <slave> to bond device <master> */

View file

@ -152,9 +152,10 @@ static void macvlan_broadcast(struct sk_buff *skb,
}
/* called under rcu_read_lock() from netif_receive_skb */
static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
{
struct macvlan_port *port;
struct sk_buff *skb = *pskb;
const struct ethhdr *eth = eth_hdr(skb);
const struct macvlan_dev *vlan;
const struct macvlan_dev *src;
@ -184,7 +185,7 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
*/
macvlan_broadcast(skb, port, src->dev,
MACVLAN_MODE_VEPA);
return skb;
return RX_HANDLER_PASS;
}
if (port->passthru)
@ -192,12 +193,12 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
else
vlan = macvlan_hash_lookup(port, eth->h_dest);
if (vlan == NULL)
return skb;
return RX_HANDLER_PASS;
dev = vlan->dev;
if (unlikely(!(dev->flags & IFF_UP))) {
kfree_skb(skb);
return NULL;
return RX_HANDLER_CONSUMED;
}
len = skb->len + ETH_HLEN;
skb = skb_share_check(skb, GFP_ATOMIC);
@ -211,7 +212,7 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
out:
macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, 0);
return NULL;
return RX_HANDLER_CONSUMED;
}
static int macvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)

View file

@ -390,7 +390,55 @@ enum gro_result {
};
typedef enum gro_result gro_result_t;
typedef struct sk_buff *rx_handler_func_t(struct sk_buff *skb);
/*
* enum rx_handler_result - Possible return values for rx_handlers.
* @RX_HANDLER_CONSUMED: skb was consumed by rx_handler, do not process it
* further.
* @RX_HANDLER_ANOTHER: Do another round in receive path. This is indicated in
* case skb->dev was changed by rx_handler.
* @RX_HANDLER_EXACT: Force exact delivery, no wildcard.
* @RX_HANDLER_PASS: Do nothing, passe the skb as if no rx_handler was called.
*
* rx_handlers are functions called from inside __netif_receive_skb(), to do
* special processing of the skb, prior to delivery to protocol handlers.
*
* Currently, a net_device can only have a single rx_handler registered. Trying
* to register a second rx_handler will return -EBUSY.
*
* To register a rx_handler on a net_device, use netdev_rx_handler_register().
* To unregister a rx_handler on a net_device, use
* netdev_rx_handler_unregister().
*
* Upon return, rx_handler is expected to tell __netif_receive_skb() what to
* do with the skb.
*
* If the rx_handler consumed to skb in some way, it should return
* RX_HANDLER_CONSUMED. This is appropriate when the rx_handler arranged for
* the skb to be delivered in some other ways.
*
* If the rx_handler changed skb->dev, to divert the skb to another
* net_device, it should return RX_HANDLER_ANOTHER. The rx_handler for the
* new device will be called if it exists.
*
* If the rx_handler consider the skb should be ignored, it should return
* RX_HANDLER_EXACT. The skb will only be delivered to protocol handlers that
* are registred on exact device (ptype->dev == skb->dev).
*
* If the rx_handler didn't changed skb->dev, but want the skb to be normally
* delivered, it should return RX_HANDLER_PASS.
*
* A device without a registered rx_handler will behave as if rx_handler
* returned RX_HANDLER_PASS.
*/
enum rx_handler_result {
RX_HANDLER_CONSUMED,
RX_HANDLER_ANOTHER,
RX_HANDLER_EXACT,
RX_HANDLER_PASS,
};
typedef enum rx_handler_result rx_handler_result_t;
typedef rx_handler_result_t rx_handler_func_t(struct sk_buff **pskb);
extern void __napi_schedule(struct napi_struct *n);

View file

@ -388,10 +388,7 @@ struct sk_buff {
kmemcheck_bitfield_begin(flags2);
__u16 queue_mapping:16;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
__u8 ndisc_nodetype:2,
deliver_no_wcard:1;
#else
__u8 deliver_no_wcard:1;
__u8 ndisc_nodetype:2;
#endif
__u8 ooo_okay:1;
kmemcheck_bitfield_end(flags2);

View file

@ -139,21 +139,22 @@ static inline int is_link_local(const unsigned char *dest)
* Return NULL if skb is handled
* note: already called with rcu_read_lock
*/
struct sk_buff *br_handle_frame(struct sk_buff *skb)
rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
{
struct net_bridge_port *p;
struct sk_buff *skb = *pskb;
const unsigned char *dest = eth_hdr(skb)->h_dest;
br_should_route_hook_t *rhook;
if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
return skb;
return RX_HANDLER_PASS;
if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
goto drop;
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
return NULL;
return RX_HANDLER_CONSUMED;
p = br_port_get_rcu(skb->dev);
@ -167,10 +168,12 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
goto forward;
if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
NULL, br_handle_local_finish))
return NULL; /* frame consumed by filter */
else
return skb; /* continue processing */
NULL, br_handle_local_finish)) {
return RX_HANDLER_CONSUMED; /* consumed by filter */
} else {
*pskb = skb;
return RX_HANDLER_PASS; /* continue processing */
}
}
forward:
@ -178,8 +181,10 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
case BR_STATE_FORWARDING:
rhook = rcu_dereference(br_should_route_hook);
if (rhook) {
if ((*rhook)(skb))
return skb;
if ((*rhook)(skb)) {
*pskb = skb;
return RX_HANDLER_PASS;
}
dest = eth_hdr(skb)->h_dest;
}
/* fall through */
@ -194,5 +199,5 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
drop:
kfree_skb(skb);
}
return NULL;
return RX_HANDLER_CONSUMED;
}

View file

@ -379,7 +379,7 @@ extern void br_features_recompute(struct net_bridge *br);
/* br_input.c */
extern int br_handle_frame_finish(struct sk_buff *skb);
extern struct sk_buff *br_handle_frame(struct sk_buff *skb);
extern rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
/* br_ioctl.c */
extern int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);

View file

@ -3070,6 +3070,8 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb,
* on a failure.
*
* The caller must hold the rtnl_mutex.
*
* For a general description of rx_handler, see enum rx_handler_result.
*/
int netdev_rx_handler_register(struct net_device *dev,
rx_handler_func_t *rx_handler,
@ -3129,6 +3131,7 @@ static int __netif_receive_skb(struct sk_buff *skb)
rx_handler_func_t *rx_handler;
struct net_device *orig_dev;
struct net_device *null_or_dev;
bool deliver_exact = false;
int ret = NET_RX_DROP;
__be16 type;
@ -3181,18 +3184,22 @@ static int __netif_receive_skb(struct sk_buff *skb)
rx_handler = rcu_dereference(skb->dev->rx_handler);
if (rx_handler) {
struct net_device *prev_dev;
if (pt_prev) {
ret = deliver_skb(skb, pt_prev, orig_dev);
pt_prev = NULL;
}
prev_dev = skb->dev;
skb = rx_handler(skb);
if (!skb)
switch (rx_handler(&skb)) {
case RX_HANDLER_CONSUMED:
goto out;
if (skb->dev != prev_dev)
case RX_HANDLER_ANOTHER:
goto another_round;
case RX_HANDLER_EXACT:
deliver_exact = true;
case RX_HANDLER_PASS:
break;
default:
BUG();
}
}
if (vlan_tx_tag_present(skb)) {
@ -3210,7 +3217,7 @@ static int __netif_receive_skb(struct sk_buff *skb)
vlan_on_bond_hook(skb);
/* deliver only exact match when indicated */
null_or_dev = skb->deliver_no_wcard ? skb->dev : NULL;
null_or_dev = deliver_exact ? skb->dev : NULL;
type = skb->protocol;
list_for_each_entry_rcu(ptype,

View file

@ -523,7 +523,6 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
new->ip_summed = old->ip_summed;
skb_copy_queue_mapping(new, old);
new->priority = old->priority;
new->deliver_no_wcard = old->deliver_no_wcard;
#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
new->ipvs_property = old->ipvs_property;
#endif