1 /*
2  * Common code for low-level network console, dump, and debugger code
3  *
4  * Derived from netconsole, kgdb-over-ethernet, and netdump patches
5  */
6 
7 #ifndef _LINUX_NETPOLL_H
8 #define _LINUX_NETPOLL_H
9 
10 #include <linux/netdevice.h>
11 #include <linux/interrupt.h>
12 #include <linux/rcupdate.h>
13 #include <linux/list.h>
14 
15 struct netpoll {
16 	struct net_device *dev;
17 	char dev_name[IFNAMSIZ];
18 	const char *name;
19 	void (*rx_hook)(struct netpoll *, int, char *, int);
20 
21 	__be32 local_ip, remote_ip;
22 	u16 local_port, remote_port;
23 	u8 remote_mac[ETH_ALEN];
24 
25 	struct list_head rx; /* rx_np list element */
26 };
27 
28 struct netpoll_info {
29 	atomic_t refcnt;
30 
31 	int rx_flags;
32 	spinlock_t rx_lock;
33 	struct list_head rx_np; /* netpolls that registered an rx_hook */
34 
35 	struct sk_buff_head arp_tx; /* list of arp requests to reply to */
36 	struct sk_buff_head txq;
37 
38 	struct delayed_work tx_work;
39 
40 	struct netpoll *netpoll;
41 };
42 
43 void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
44 void netpoll_print_options(struct netpoll *np);
45 int netpoll_parse_options(struct netpoll *np, char *opt);
46 int __netpoll_setup(struct netpoll *np);
47 int netpoll_setup(struct netpoll *np);
48 int netpoll_trap(void);
49 void netpoll_set_trap(int trap);
50 void __netpoll_cleanup(struct netpoll *np);
51 void netpoll_cleanup(struct netpoll *np);
52 int __netpoll_rx(struct sk_buff *skb);
53 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
54 			     struct net_device *dev);
netpoll_send_skb(struct netpoll * np,struct sk_buff * skb)55 static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
56 {
57 	netpoll_send_skb_on_dev(np, skb, np->dev);
58 }
59 
60 
61 
62 #ifdef CONFIG_NETPOLL
netpoll_rx(struct sk_buff * skb)63 static inline bool netpoll_rx(struct sk_buff *skb)
64 {
65 	struct netpoll_info *npinfo;
66 	unsigned long flags;
67 	bool ret = false;
68 
69 	local_irq_save(flags);
70 	npinfo = rcu_dereference_bh(skb->dev->npinfo);
71 
72 	if (!npinfo || (list_empty(&npinfo->rx_np) && !npinfo->rx_flags))
73 		goto out;
74 
75 	spin_lock(&npinfo->rx_lock);
76 	/* check rx_flags again with the lock held */
77 	if (npinfo->rx_flags && __netpoll_rx(skb))
78 		ret = true;
79 	spin_unlock(&npinfo->rx_lock);
80 
81 out:
82 	local_irq_restore(flags);
83 	return ret;
84 }
85 
netpoll_rx_on(struct sk_buff * skb)86 static inline int netpoll_rx_on(struct sk_buff *skb)
87 {
88 	struct netpoll_info *npinfo = rcu_dereference_bh(skb->dev->npinfo);
89 
90 	return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
91 }
92 
netpoll_receive_skb(struct sk_buff * skb)93 static inline int netpoll_receive_skb(struct sk_buff *skb)
94 {
95 	if (!list_empty(&skb->dev->napi_list))
96 		return netpoll_rx(skb);
97 	return 0;
98 }
99 
netpoll_poll_lock(struct napi_struct * napi)100 static inline void *netpoll_poll_lock(struct napi_struct *napi)
101 {
102 	struct net_device *dev = napi->dev;
103 
104 	if (dev && dev->npinfo) {
105 		spin_lock(&napi->poll_lock);
106 		napi->poll_owner = smp_processor_id();
107 		return napi;
108 	}
109 	return NULL;
110 }
111 
netpoll_poll_unlock(void * have)112 static inline void netpoll_poll_unlock(void *have)
113 {
114 	struct napi_struct *napi = have;
115 
116 	if (napi) {
117 		napi->poll_owner = -1;
118 		spin_unlock(&napi->poll_lock);
119 	}
120 }
121 
netpoll_tx_running(struct net_device * dev)122 static inline int netpoll_tx_running(struct net_device *dev)
123 {
124 	return irqs_disabled();
125 }
126 
127 #else
netpoll_rx(struct sk_buff * skb)128 static inline bool netpoll_rx(struct sk_buff *skb)
129 {
130 	return 0;
131 }
netpoll_rx_on(struct sk_buff * skb)132 static inline int netpoll_rx_on(struct sk_buff *skb)
133 {
134 	return 0;
135 }
netpoll_receive_skb(struct sk_buff * skb)136 static inline int netpoll_receive_skb(struct sk_buff *skb)
137 {
138 	return 0;
139 }
netpoll_poll_lock(struct napi_struct * napi)140 static inline void *netpoll_poll_lock(struct napi_struct *napi)
141 {
142 	return NULL;
143 }
netpoll_poll_unlock(void * have)144 static inline void netpoll_poll_unlock(void *have)
145 {
146 }
netpoll_netdev_init(struct net_device * dev)147 static inline void netpoll_netdev_init(struct net_device *dev)
148 {
149 }
netpoll_tx_running(struct net_device * dev)150 static inline int netpoll_tx_running(struct net_device *dev)
151 {
152 	return 0;
153 }
154 #endif
155 
156 #endif
157