uml: SMP locking commentary
[linux-2.6] / arch / um / drivers / slirp_kern.c
1 /*
2  * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL.
4  */
5
6 #include <linux/if_arp.h>
7 #include "linux/init.h"
8 #include <linux/netdevice.h>
9 #include <linux/string.h>
10 #include "net_kern.h"
11 #include "net_user.h"
12 #include "slirp.h"
13
14 struct slirp_init {
15         struct arg_list_dummy_wrapper argw;  /* XXX should be simpler... */
16 };
17
18 void slirp_init(struct net_device *dev, void *data)
19 {
20         struct uml_net_private *private;
21         struct slirp_data *spri;
22         struct slirp_init *init = data;
23         int i;
24
25         private = dev->priv;
26         spri = (struct slirp_data *) private->user;
27
28         spri->argw = init->argw;
29         spri->pid = -1;
30         spri->slave = -1;
31         spri->dev = dev;
32
33         slip_proto_init(&spri->slip);
34
35         dev->init = NULL;
36         dev->hard_header_len = 0;
37         dev->header_ops = NULL;
38         dev->addr_len = 0;
39         dev->type = ARPHRD_SLIP;
40         dev->tx_queue_len = 256;
41         dev->flags = IFF_NOARP;
42         printk("SLIRP backend - command line:");
43         for (i = 0; spri->argw.argv[i] != NULL; i++)
44                 printk(" '%s'",spri->argw.argv[i]);
45         printk("\n");
46 }
47
48 static unsigned short slirp_protocol(struct sk_buff *skbuff)
49 {
50         return htons(ETH_P_IP);
51 }
52
53 static int slirp_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
54 {
55         return slirp_user_read(fd, skb_mac_header(skb), skb->dev->mtu,
56                                (struct slirp_data *) &lp->user);
57 }
58
59 static int slirp_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
60 {
61         return slirp_user_write(fd, skb->data, skb->len,
62                                 (struct slirp_data *) &lp->user);
63 }
64
65 const struct net_kern_info slirp_kern_info = {
66         .init                   = slirp_init,
67         .protocol               = slirp_protocol,
68         .read                   = slirp_read,
69         .write                  = slirp_write,
70 };
71
72 static int slirp_setup(char *str, char **mac_out, void *data)
73 {
74         struct slirp_init *init = data;
75         int i=0;
76
77         *init = ((struct slirp_init) { .argw = { { "slirp", NULL  } } });
78
79         str = split_if_spec(str, mac_out, NULL);
80
81         if (str == NULL) /* no command line given after MAC addr */
82                 return 1;
83
84         do {
85                 if (i >= SLIRP_MAX_ARGS - 1) {
86                         printk(KERN_WARNING "slirp_setup: truncating slirp "
87                                "arguments\n");
88                         break;
89                 }
90                 init->argw.argv[i++] = str;
91                 while(*str && *str!=',') {
92                         if (*str == '_')
93                                 *str=' ';
94                         str++;
95                 }
96                 if (*str != ',')
97                         break;
98                 *str++ = '\0';
99         } while (1);
100
101         init->argw.argv[i] = NULL;
102         return 1;
103 }
104
105 static struct transport slirp_transport = {
106         .list           = LIST_HEAD_INIT(slirp_transport.list),
107         .name           = "slirp",
108         .setup          = slirp_setup,
109         .user           = &slirp_user_info,
110         .kern           = &slirp_kern_info,
111         .private_size   = sizeof(struct slirp_data),
112         .setup_size     = sizeof(struct slirp_init),
113 };
114
115 static int register_slirp(void)
116 {
117         register_transport(&slirp_transport);
118         return 0;
119 }
120
121 late_initcall(register_slirp);