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/slab.h> 18#include <linux/init.h> 19#include <linux/netdevice.h> 20#include <linux/netfilter.h> 21#include <linux/spinlock.h> 22#include <net/netlink.h> 23#include <linux/netfilter_decnet.h> 24 25#include <net/sock.h> 26#include <net/flow.h> 27#include <net/dn.h> 28#include <net/dn_route.h> 29 30static struct sock *dnrmg = NULL; 31 32 33static 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 sk_buff_data_t old_tail; 38 struct nlmsghdr *nlh; 39 unsigned char *ptr; 40 struct nf_dn_rtmsg *rtm; 41 42 size = NLMSG_ALIGN(rt_skb->len) + 43 NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg)); 44 skb = nlmsg_new(size, GFP_ATOMIC); 45 if (!skb) { 46 *errp = -ENOMEM; 47 return NULL; 48 } 49 old_tail = skb->tail; 50 nlh = nlmsg_put(skb, 0, 0, 0, size, 0); 51 if (!nlh) { 52 kfree_skb(skb); 53 *errp = -ENOMEM; 54 return NULL; 55 } 56 rtm = (struct nf_dn_rtmsg *)nlmsg_data(nlh); 57 rtm->nfdn_ifindex = rt_skb->dev->ifindex; 58 ptr = NFDN_RTMSG(rtm); 59 skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len); 60 nlh->nlmsg_len = skb->tail - old_tail; 61 return skb; 62} 63 64static 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 90static unsigned int dnrmg_hook(const struct nf_hook_ops *ops, 91 struct sk_buff *skb, 92 const struct net_device *in, 93 const struct net_device *out, 94 int (*okfn)(struct sk_buff *)) 95{ 96 dnrmg_send_peer(skb); 97 return NF_ACCEPT; 98} 99 100 101#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0) 102 103static 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 (!netlink_capable(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 118static struct nf_hook_ops dnrmg_ops __read_mostly = { 119 .hook = dnrmg_hook, 120 .pf = NFPROTO_DECNET, 121 .hooknum = NF_DN_ROUTE, 122 .priority = NF_DN_PRI_DNRTMSG, 123}; 124 125static int __init dn_rtmsg_init(void) 126{ 127 int rv = 0; 128 struct netlink_kernel_cfg cfg = { 129 .groups = DNRNG_NLGRP_MAX, 130 .input = dnrmg_receive_user_skb, 131 }; 132 133 dnrmg = netlink_kernel_create(&init_net, NETLINK_DNRTMSG, &cfg); 134 if (dnrmg == NULL) { 135 printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket"); 136 return -ENOMEM; 137 } 138 139 rv = nf_register_hook(&dnrmg_ops); 140 if (rv) { 141 netlink_kernel_release(dnrmg); 142 } 143 144 return rv; 145} 146 147static void __exit dn_rtmsg_fini(void) 148{ 149 nf_unregister_hook(&dnrmg_ops); 150 netlink_kernel_release(dnrmg); 151} 152 153 154MODULE_DESCRIPTION("DECnet Routing Message Grabulator"); 155MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>"); 156MODULE_LICENSE("GPL"); 157MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG); 158 159module_init(dn_rtmsg_init); 160module_exit(dn_rtmsg_fini); 161 162