[NET]: Support multiple network namespaces with netlink
[linux-2.6.git] / net / decnet / netfilter / dn_rtmsg.c
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 Routing Message Grabulator
7  *
8  *              (C) 2000 ChyGwyn Limited  -  http://www.chygwyn.com/
9  *              This code may be copied under the GPL v.2 or at your option
10  *              any later version.
11  *
12  * Author:      Steven Whitehouse <steve@chygwyn.com>
13  *
14  */
15 #include <linux/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/init.h>
18 #include <linux/netdevice.h>
19 #include <linux/netfilter.h>
20 #include <linux/spinlock.h>
21 #include <linux/netlink.h>
22 #include <linux/netfilter_decnet.h>
23
24 #include <net/sock.h>
25 #include <net/flow.h>
26 #include <net/dn.h>
27 #include <net/dn_route.h>
28
29 static struct sock *dnrmg = NULL;
30
31
32 static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp)
33 {
34         struct sk_buff *skb = NULL;
35         size_t size;
36         sk_buff_data_t old_tail;
37         struct nlmsghdr *nlh;
38         unsigned char *ptr;
39         struct nf_dn_rtmsg *rtm;
40
41         size = NLMSG_SPACE(rt_skb->len);
42         size += NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
43         skb = alloc_skb(size, GFP_ATOMIC);
44         if (!skb)
45                 goto nlmsg_failure;
46         old_tail = skb->tail;
47         nlh = NLMSG_PUT(skb, 0, 0, 0, size - sizeof(*nlh));
48         rtm = (struct nf_dn_rtmsg *)NLMSG_DATA(nlh);
49         rtm->nfdn_ifindex = rt_skb->dev->ifindex;
50         ptr = NFDN_RTMSG(rtm);
51         skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
52         nlh->nlmsg_len = skb->tail - old_tail;
53         return skb;
54
55 nlmsg_failure:
56         if (skb)
57                 kfree_skb(skb);
58         *errp = -ENOMEM;
59         if (net_ratelimit())
60                 printk(KERN_ERR "dn_rtmsg: error creating netlink message\n");
61         return NULL;
62 }
63
64 static void dnrmg_send_peer(struct sk_buff *skb)
65 {
66         struct sk_buff *skb2;
67         int status = 0;
68         int group = 0;
69         unsigned char flags = *skb->data;
70
71         switch(flags & DN_RT_CNTL_MSK) {
72                 case DN_RT_PKT_L1RT:
73                         group = DNRNG_NLGRP_L1;
74                         break;
75                 case DN_RT_PKT_L2RT:
76                         group = DNRNG_NLGRP_L2;
77                         break;
78                 default:
79                         return;
80         }
81
82         skb2 = dnrmg_build_message(skb, &status);
83         if (skb2 == NULL)
84                 return;
85         NETLINK_CB(skb2).dst_group = group;
86         netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
87 }
88
89
90 static unsigned int dnrmg_hook(unsigned int hook,
91                         struct sk_buff **pskb,
92                         const struct net_device *in,
93                         const struct net_device *out,
94                         int (*okfn)(struct sk_buff *))
95 {
96         dnrmg_send_peer(*pskb);
97         return NF_ACCEPT;
98 }
99
100
101 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
102
103 static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
104 {
105         struct nlmsghdr *nlh = nlmsg_hdr(skb);
106
107         if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
108                 return;
109
110         if (security_netlink_recv(skb, CAP_NET_ADMIN))
111                 RCV_SKB_FAIL(-EPERM);
112
113         /* Eventually we might send routing messages too */
114
115         RCV_SKB_FAIL(-EINVAL);
116 }
117
118 static void dnrmg_receive_user_sk(struct sock *sk, int len)
119 {
120         struct sk_buff *skb;
121         unsigned int qlen = skb_queue_len(&sk->sk_receive_queue);
122
123         for (; qlen && (skb = skb_dequeue(&sk->sk_receive_queue)); qlen--) {
124                 dnrmg_receive_user_skb(skb);
125                 kfree_skb(skb);
126         }
127 }
128
129 static struct nf_hook_ops dnrmg_ops = {
130         .hook           = dnrmg_hook,
131         .pf             = PF_DECnet,
132         .hooknum        = NF_DN_ROUTE,
133         .priority       = NF_DN_PRI_DNRTMSG,
134 };
135
136 static int __init dn_rtmsg_init(void)
137 {
138         int rv = 0;
139
140         dnrmg = netlink_kernel_create(&init_net,
141                                       NETLINK_DNRTMSG, DNRNG_NLGRP_MAX,
142                                       dnrmg_receive_user_sk, NULL, THIS_MODULE);
143         if (dnrmg == NULL) {
144                 printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
145                 return -ENOMEM;
146         }
147
148         rv = nf_register_hook(&dnrmg_ops);
149         if (rv) {
150                 sock_release(dnrmg->sk_socket);
151         }
152
153         return rv;
154 }
155
156 static void __exit dn_rtmsg_fini(void)
157 {
158         nf_unregister_hook(&dnrmg_ops);
159         sock_release(dnrmg->sk_socket);
160 }
161
162
163 MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
164 MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
165 MODULE_LICENSE("GPL");
166 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
167
168 module_init(dn_rtmsg_init);
169 module_exit(dn_rtmsg_fini);
170