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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 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 | ||
23 | #include <net/sock.h> | |
24 | #include <net/flow.h> | |
25 | #include <net/dn.h> | |
26 | #include <net/dn_route.h> | |
27 | ||
28 | #include <linux/netfilter_decnet.h> | |
29 | ||
30 | static struct sock *dnrmg = NULL; | |
31 | ||
32 | ||
33 | static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp) | |
34 | { | |
35 | struct sk_buff *skb = NULL; | |
36 | size_t size; | |
37 | unsigned char *old_tail; | |
38 | struct nlmsghdr *nlh; | |
39 | unsigned char *ptr; | |
40 | struct nf_dn_rtmsg *rtm; | |
41 | ||
42 | size = NLMSG_SPACE(rt_skb->len); | |
43 | size += NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg)); | |
44 | skb = alloc_skb(size, GFP_ATOMIC); | |
45 | if (!skb) | |
46 | goto nlmsg_failure; | |
47 | old_tail = skb->tail; | |
48 | nlh = NLMSG_PUT(skb, 0, 0, 0, size - sizeof(*nlh)); | |
49 | rtm = (struct nf_dn_rtmsg *)NLMSG_DATA(nlh); | |
50 | rtm->nfdn_ifindex = rt_skb->dev->ifindex; | |
51 | ptr = NFDN_RTMSG(rtm); | |
52 | memcpy(ptr, rt_skb->data, rt_skb->len); | |
53 | nlh->nlmsg_len = skb->tail - old_tail; | |
54 | return skb; | |
55 | ||
56 | nlmsg_failure: | |
57 | if (skb) | |
58 | kfree_skb(skb); | |
59 | *errp = -ENOMEM; | |
60 | if (net_ratelimit()) | |
61 | printk(KERN_ERR "dn_rtmsg: error creating netlink message\n"); | |
62 | return NULL; | |
63 | } | |
64 | ||
65 | static void dnrmg_send_peer(struct sk_buff *skb) | |
66 | { | |
67 | struct sk_buff *skb2; | |
68 | int status = 0; | |
69 | int group = 0; | |
70 | unsigned char flags = *skb->data; | |
71 | ||
72 | switch(flags & DN_RT_CNTL_MSK) { | |
73 | case DN_RT_PKT_L1RT: | |
74 | group = DNRMG_L1_GROUP; | |
75 | break; | |
76 | case DN_RT_PKT_L2RT: | |
77 | group = DNRMG_L2_GROUP; | |
78 | break; | |
79 | default: | |
80 | return; | |
81 | } | |
82 | ||
83 | skb2 = dnrmg_build_message(skb, &status); | |
84 | if (skb2 == NULL) | |
85 | return; | |
86 | NETLINK_CB(skb2).dst_groups = group; | |
87 | netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC); | |
88 | } | |
89 | ||
90 | ||
91 | static unsigned int dnrmg_hook(unsigned int hook, | |
92 | struct sk_buff **pskb, | |
93 | const struct net_device *in, | |
94 | const struct net_device *out, | |
95 | int (*okfn)(struct sk_buff *)) | |
96 | { | |
97 | dnrmg_send_peer(*pskb); | |
98 | return NF_ACCEPT; | |
99 | } | |
100 | ||
101 | ||
102 | #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0) | |
103 | ||
104 | static inline void dnrmg_receive_user_skb(struct sk_buff *skb) | |
105 | { | |
106 | struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; | |
107 | ||
108 | if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) | |
109 | return; | |
110 | ||
111 | if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) | |
112 | RCV_SKB_FAIL(-EPERM); | |
113 | ||
114 | /* Eventually we might send routing messages too */ | |
115 | ||
116 | RCV_SKB_FAIL(-EINVAL); | |
117 | } | |
118 | ||
119 | static void dnrmg_receive_user_sk(struct sock *sk, int len) | |
120 | { | |
121 | struct sk_buff *skb; | |
2a0a6ebe | 122 | unsigned int qlen = skb_queue_len(&sk->sk_receive_queue); |
1da177e4 | 123 | |
09e14305 | 124 | for (; qlen && (skb = skb_dequeue(&sk->sk_receive_queue)); qlen--) { |
1da177e4 LT |
125 | dnrmg_receive_user_skb(skb); |
126 | kfree_skb(skb); | |
127 | } | |
128 | } | |
129 | ||
130 | static struct nf_hook_ops dnrmg_ops = { | |
131 | .hook = dnrmg_hook, | |
132 | .pf = PF_DECnet, | |
133 | .hooknum = NF_DN_ROUTE, | |
134 | .priority = NF_DN_PRI_DNRTMSG, | |
135 | }; | |
136 | ||
137 | static int __init init(void) | |
138 | { | |
139 | int rv = 0; | |
140 | ||
141 | dnrmg = netlink_kernel_create(NETLINK_DNRTMSG, dnrmg_receive_user_sk); | |
142 | if (dnrmg == NULL) { | |
143 | printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket"); | |
144 | return -ENOMEM; | |
145 | } | |
146 | ||
147 | rv = nf_register_hook(&dnrmg_ops); | |
148 | if (rv) { | |
149 | sock_release(dnrmg->sk_socket); | |
150 | } | |
151 | ||
152 | return rv; | |
153 | } | |
154 | ||
155 | static void __exit fini(void) | |
156 | { | |
157 | nf_unregister_hook(&dnrmg_ops); | |
158 | sock_release(dnrmg->sk_socket); | |
159 | } | |
160 | ||
161 | ||
162 | MODULE_DESCRIPTION("DECnet Routing Message Grabulator"); | |
163 | MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>"); | |
164 | MODULE_LICENSE("GPL"); | |
165 | ||
166 | module_init(init); | |
167 | module_exit(fini); | |
168 |