Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * DECnet An implementation of the DECnet protocol suite for the LINUX | |
3 | * operating system. DECnet is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * DECnet Socket Timer Functions | |
7 | * | |
8 | * Author: Steve Whitehouse <SteveW@ACM.org> | |
9 | * | |
10 | * | |
11 | * Changes: | |
12 | * Steve Whitehouse : Made keepalive timer part of the same | |
13 | * timer idea. | |
14 | * Steve Whitehouse : Added checks for sk->sock_readers | |
15 | * David S. Miller : New socket locking | |
16 | * Steve Whitehouse : Timer grabs socket ref. | |
17 | */ | |
18 | #include <linux/net.h> | |
19 | #include <linux/socket.h> | |
20 | #include <linux/skbuff.h> | |
21 | #include <linux/netdevice.h> | |
22 | #include <linux/timer.h> | |
23 | #include <linux/spinlock.h> | |
24 | #include <net/sock.h> | |
25 | #include <asm/atomic.h> | |
26 | #include <net/flow.h> | |
27 | #include <net/dn.h> | |
28 | ||
29 | /* | |
30 | * Slow timer is for everything else (n * 500mS) | |
31 | */ | |
32 | ||
33 | #define SLOW_INTERVAL (HZ/2) | |
34 | ||
35 | static void dn_slow_timer(unsigned long arg); | |
36 | ||
37 | void dn_start_slow_timer(struct sock *sk) | |
38 | { | |
39 | sk->sk_timer.expires = jiffies + SLOW_INTERVAL; | |
40 | sk->sk_timer.function = dn_slow_timer; | |
41 | sk->sk_timer.data = (unsigned long)sk; | |
42 | ||
43 | add_timer(&sk->sk_timer); | |
44 | } | |
45 | ||
46 | void dn_stop_slow_timer(struct sock *sk) | |
47 | { | |
48 | del_timer(&sk->sk_timer); | |
49 | } | |
50 | ||
51 | static void dn_slow_timer(unsigned long arg) | |
52 | { | |
53 | struct sock *sk = (struct sock *)arg; | |
54 | struct dn_scp *scp = DN_SK(sk); | |
55 | ||
56 | sock_hold(sk); | |
57 | bh_lock_sock(sk); | |
58 | ||
59 | if (sock_owned_by_user(sk)) { | |
60 | sk->sk_timer.expires = jiffies + HZ / 10; | |
61 | add_timer(&sk->sk_timer); | |
62 | goto out; | |
63 | } | |
64 | ||
65 | /* | |
66 | * The persist timer is the standard slow timer used for retransmits | |
67 | * in both connection establishment and disconnection as well as | |
68 | * in the RUN state. The different states are catered for by changing | |
69 | * the function pointer in the socket. Setting the timer to a value | |
70 | * of zero turns it off. We allow the persist_fxn to turn the | |
71 | * timer off in a permant way by returning non-zero, so that | |
72 | * timer based routines may remove sockets. This is why we have a | |
73 | * sock_hold()/sock_put() around the timer to prevent the socket | |
74 | * going away in the middle. | |
75 | */ | |
76 | if (scp->persist && scp->persist_fxn) { | |
77 | if (scp->persist <= SLOW_INTERVAL) { | |
78 | scp->persist = 0; | |
79 | ||
80 | if (scp->persist_fxn(sk)) | |
81 | goto out; | |
82 | } else { | |
83 | scp->persist -= SLOW_INTERVAL; | |
84 | } | |
85 | } | |
86 | ||
87 | /* | |
88 | * Check for keepalive timeout. After the other timer 'cos if | |
89 | * the previous timer caused a retransmit, we don't need to | |
90 | * do this. scp->stamp is the last time that we sent a packet. | |
91 | * The keepalive function sends a link service packet to the | |
92 | * other end. If it remains unacknowledged, the standard | |
93 | * socket timers will eventually shut the socket down. Each | |
94 | * time we do this, scp->stamp will be updated, thus | |
95 | * we won't try and send another until scp->keepalive has passed | |
96 | * since the last successful transmission. | |
97 | */ | |
98 | if (scp->keepalive && scp->keepalive_fxn && (scp->state == DN_RUN)) { | |
99 | if ((jiffies - scp->stamp) >= scp->keepalive) | |
100 | scp->keepalive_fxn(sk); | |
101 | } | |
102 | ||
103 | sk->sk_timer.expires = jiffies + SLOW_INTERVAL; | |
104 | ||
105 | add_timer(&sk->sk_timer); | |
106 | out: | |
107 | bh_unlock_sock(sk); | |
108 | sock_put(sk); | |
109 | } |