netpoll.h

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/*
 * Common code for low-level network console, dump, and debugger code
 *
 * Derived from netconsole, kgdb-over-ethernet, and netdump patches
 */

#ifndef _LINUX_NETPOLL_H
#define _LINUX_NETPOLL_H

#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/rcupdate.h>
#include <linux/list.h>

struct netpoll {
    struct net_device *dev;
    char dev_name[IFNAMSIZ];
    const char *name;
    void (*rx_hook)(struct netpoll *, int, char *, int);

    __be32 local_ip, remote_ip;
    u16 local_port, remote_port;
    u8 remote_mac[ETH_ALEN];

    struct list_head rx; /* rx_np list element */
    struct rcu_head rcu;
};

struct netpoll_info {
    atomic_t refcnt;

    int rx_flags;
    spinlock_t rx_lock;
    struct list_head rx_np; /* netpolls that registered an rx_hook */

    struct sk_buff_head arp_tx; /* list of arp requests to reply to */
    struct sk_buff_head txq;

    struct delayed_work tx_work;

    struct netpoll *netpoll;
    struct rcu_head rcu;
};

void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
void netpoll_print_options(struct netpoll *np);
int netpoll_parse_options(struct netpoll *np, char *opt);
int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp);
int netpoll_setup(struct netpoll *np);
int netpoll_trap(void);
void netpoll_set_trap(int trap);
void __netpoll_cleanup(struct netpoll *np);
void __netpoll_free_rcu(struct netpoll *np);
void netpoll_cleanup(struct netpoll *np);
int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo);
void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
                 struct net_device *dev);
static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
    unsigned long flags;
    local_irq_save(flags);
    netpoll_send_skb_on_dev(np, skb, np->dev);
    local_irq_restore(flags);
}



#ifdef CONFIG_NETPOLL
static inline bool netpoll_rx_on(struct sk_buff *skb)
{
    struct netpoll_info *npinfo = rcu_dereference_bh(skb->dev->npinfo);

    return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
}

static inline bool netpoll_rx(struct sk_buff *skb)
{
    struct netpoll_info *npinfo;
    unsigned long flags;
    bool ret = false;

    local_irq_save(flags);

    if (!netpoll_rx_on(skb))
        goto out;

    npinfo = rcu_dereference_bh(skb->dev->npinfo);
    spin_lock(&npinfo->rx_lock);
    /* check rx_flags again with the lock held */
    if (npinfo->rx_flags && __netpoll_rx(skb, npinfo))
        ret = true;
    spin_unlock(&npinfo->rx_lock);

out:
    local_irq_restore(flags);
    return ret;
}

static inline int netpoll_receive_skb(struct sk_buff *skb)
{
    if (!list_empty(&skb->dev->napi_list))
        return netpoll_rx(skb);
    return 0;
}

static inline void *netpoll_poll_lock(struct napi_struct *napi)
{
    struct net_device *dev = napi->dev;

    if (dev && dev->npinfo) {
        spin_lock(&napi->poll_lock);
        napi->poll_owner = smp_processor_id();
        return napi;
    }
    return NULL;
}

static inline void netpoll_poll_unlock(void *have)
{
    struct napi_struct *napi = have;

    if (napi) {
        napi->poll_owner = -1;
        spin_unlock(&napi->poll_lock);
    }
}

static inline bool netpoll_tx_running(struct net_device *dev)
{
    return irqs_disabled();
}

#else
static inline bool netpoll_rx(struct sk_buff *skb)
{
    return false;
}
static inline bool netpoll_rx_on(struct sk_buff *skb)
{
    return false;
}
static inline int netpoll_receive_skb(struct sk_buff *skb)
{
    return 0;
}
static inline void *netpoll_poll_lock(struct napi_struct *napi)
{
    return NULL;
}
static inline void netpoll_poll_unlock(void *have)
{
}
static inline void netpoll_netdev_init(struct net_device *dev)
{
}
static inline bool netpoll_tx_running(struct net_device *dev)
{
    return false;
}
#endif

#endif