Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 1 | /* Netfilter messages via netlink socket. Allows for user space |
| 2 | * protocol helpers and general trouble making from userspace. |
| 3 | * |
| 4 | * (C) 2001 by Jay Schulist <jschlst@samba.org>, |
| 5 | * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org> |
Pablo Neira Ayuso | 67ca396 | 2007-03-14 16:40:38 -0700 | [diff] [blame] | 6 | * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org> |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 7 | * |
| 8 | * Initial netfilter messages via netlink development funded and |
| 9 | * generally made possible by Network Robots, Inc. (www.networkrobots.com) |
| 10 | * |
| 11 | * Further development of this code funded by Astaro AG (http://www.astaro.com) |
| 12 | * |
| 13 | * This software may be used and distributed according to the terms |
| 14 | * of the GNU General Public License, incorporated herein by reference. |
| 15 | */ |
| 16 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 17 | #include <linux/module.h> |
| 18 | #include <linux/types.h> |
| 19 | #include <linux/socket.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/major.h> |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 22 | #include <linux/timer.h> |
| 23 | #include <linux/string.h> |
| 24 | #include <linux/sockios.h> |
| 25 | #include <linux/net.h> |
| 26 | #include <linux/fcntl.h> |
| 27 | #include <linux/skbuff.h> |
| 28 | #include <asm/uaccess.h> |
| 29 | #include <asm/system.h> |
| 30 | #include <net/sock.h> |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 31 | #include <net/netlink.h> |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 32 | #include <linux/init.h> |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 33 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 34 | #include <linux/netlink.h> |
| 35 | #include <linux/netfilter/nfnetlink.h> |
| 36 | |
| 37 | MODULE_LICENSE("GPL"); |
Harald Welte | 4fdb3bb | 2005-08-09 19:40:55 -0700 | [diff] [blame] | 38 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| 39 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 40 | |
| 41 | static char __initdata nfversion[] = "0.30"; |
| 42 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 43 | static struct sock *nfnl = NULL; |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 44 | static const struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT]; |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 45 | static DEFINE_MUTEX(nfnl_mutex); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 46 | |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 47 | static void nfnl_lock(void) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 48 | { |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 49 | mutex_lock(&nfnl_mutex); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 50 | } |
| 51 | |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 52 | static int nfnl_trylock(void) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 53 | { |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 54 | return !mutex_trylock(&nfnl_mutex); |
| 55 | } |
| 56 | |
| 57 | static void __nfnl_unlock(void) |
| 58 | { |
| 59 | mutex_unlock(&nfnl_mutex); |
| 60 | } |
| 61 | |
| 62 | static void nfnl_unlock(void) |
| 63 | { |
| 64 | mutex_unlock(&nfnl_mutex); |
| 65 | if (nfnl->sk_receive_queue.qlen) |
| 66 | nfnl->sk_data_ready(nfnl, 0); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 67 | } |
| 68 | |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 69 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 70 | { |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 71 | nfnl_lock(); |
Harald Welte | 0ab43f8 | 2005-08-09 19:43:44 -0700 | [diff] [blame] | 72 | if (subsys_table[n->subsys_id]) { |
| 73 | nfnl_unlock(); |
| 74 | return -EBUSY; |
| 75 | } |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 76 | subsys_table[n->subsys_id] = n; |
| 77 | nfnl_unlock(); |
| 78 | |
| 79 | return 0; |
| 80 | } |
Pablo Neira Ayuso | f4bc177 | 2007-03-14 16:42:11 -0700 | [diff] [blame] | 81 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 82 | |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 83 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 84 | { |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 85 | nfnl_lock(); |
| 86 | subsys_table[n->subsys_id] = NULL; |
| 87 | nfnl_unlock(); |
| 88 | |
| 89 | return 0; |
| 90 | } |
Pablo Neira Ayuso | f4bc177 | 2007-03-14 16:42:11 -0700 | [diff] [blame] | 91 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 92 | |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 93 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 94 | { |
| 95 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); |
| 96 | |
Pablo Neira Ayuso | ac0f1d9 | 2007-03-14 16:41:28 -0700 | [diff] [blame] | 97 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 98 | return NULL; |
| 99 | |
| 100 | return subsys_table[subsys_id]; |
| 101 | } |
| 102 | |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 103 | static inline const struct nfnl_callback * |
| 104 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 105 | { |
| 106 | u_int8_t cb_id = NFNL_MSG_TYPE(type); |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 107 | |
Pablo Neira Ayuso | 67ca396 | 2007-03-14 16:40:38 -0700 | [diff] [blame] | 108 | if (cb_id >= ss->cb_count) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 109 | return NULL; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 110 | |
| 111 | return &ss->cb[cb_id]; |
| 112 | } |
| 113 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 114 | /** |
| 115 | * nfnetlink_check_attributes - check and parse nfnetlink attributes |
| 116 | * |
| 117 | * subsys: nfnl subsystem for which this message is to be parsed |
| 118 | * nlmsghdr: netlink message to be checked/parsed |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 119 | * cda: array of pointers, needs to be at least subsys->attr_count+1 big |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 120 | * |
| 121 | */ |
| 122 | static int |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 123 | nfnetlink_check_attributes(const struct nfnetlink_subsystem *subsys, |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 124 | struct nlmsghdr *nlh, struct nlattr *cda[]) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 125 | { |
Pablo Neira Ayuso | d9e6d02 | 2007-03-14 16:41:03 -0700 | [diff] [blame] | 126 | int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg)); |
Harald Welte | 927ccbc | 2005-08-09 20:03:40 -0700 | [diff] [blame] | 127 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
Pablo Neira Ayuso | ac6d141 | 2007-03-14 16:45:39 -0700 | [diff] [blame] | 128 | u_int16_t attr_count = subsys->cb[cb_id].attr_count; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 129 | |
| 130 | /* check attribute lengths. */ |
Harald Welte | a42827b | 2005-08-09 20:03:54 -0700 | [diff] [blame] | 131 | if (likely(nlh->nlmsg_len > min_len)) { |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 132 | struct nlattr *attr = (void *)nlh + NLMSG_ALIGN(min_len); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 133 | int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len); |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 134 | nla_parse(cda, attr_count, attr, attrlen, NULL); |
Harald Welte | a42827b | 2005-08-09 20:03:54 -0700 | [diff] [blame] | 135 | } |
| 136 | |
| 137 | /* implicit: if nlmsg_len == min_len, we return 0, and an empty |
| 138 | * (zeroed) cda[] array. The message is valid, but empty. */ |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 139 | |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 140 | return 0; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 141 | } |
| 142 | |
Patrick McHardy | a242769 | 2006-03-20 18:03:59 -0800 | [diff] [blame] | 143 | int nfnetlink_has_listeners(unsigned int group) |
| 144 | { |
| 145 | return netlink_has_listeners(nfnl, group); |
| 146 | } |
| 147 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); |
| 148 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 149 | int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo) |
| 150 | { |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 151 | int err = 0; |
| 152 | |
Patrick McHardy | ac6d439 | 2005-08-14 19:29:52 -0700 | [diff] [blame] | 153 | NETLINK_CB(skb).dst_group = group; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 154 | if (echo) |
| 155 | atomic_inc(&skb->users); |
Patrick McHardy | 4498121 | 2007-02-27 09:56:42 -0800 | [diff] [blame] | 156 | netlink_broadcast(nfnl, skb, pid, group, gfp_any()); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 157 | if (echo) |
| 158 | err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT); |
| 159 | |
| 160 | return err; |
| 161 | } |
Pablo Neira Ayuso | f4bc177 | 2007-03-14 16:42:11 -0700 | [diff] [blame] | 162 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 163 | |
| 164 | int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags) |
| 165 | { |
| 166 | return netlink_unicast(nfnl, skb, pid, flags); |
| 167 | } |
Pablo Neira Ayuso | f4bc177 | 2007-03-14 16:42:11 -0700 | [diff] [blame] | 168 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 169 | |
| 170 | /* Process one complete nfnetlink message. */ |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 171 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 172 | { |
Patrick McHardy | 7c8d4cb | 2007-09-28 14:15:45 -0700 | [diff] [blame] | 173 | const struct nfnl_callback *nc; |
| 174 | const struct nfnetlink_subsystem *ss; |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 175 | int type, err; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 176 | |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 177 | if (security_netlink_recv(skb, CAP_NET_ADMIN)) |
| 178 | return -EPERM; |
Harald Welte | 37d2e7a | 2005-11-14 15:24:59 -0800 | [diff] [blame] | 179 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 180 | /* All the messages must at least contain nfgenmsg */ |
Pablo Neira Ayuso | 67ca396 | 2007-03-14 16:40:38 -0700 | [diff] [blame] | 181 | if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg))) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 182 | return 0; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 183 | |
| 184 | type = nlh->nlmsg_type; |
| 185 | ss = nfnetlink_get_subsys(type); |
Harald Welte | 0ab43f8 | 2005-08-09 19:43:44 -0700 | [diff] [blame] | 186 | if (!ss) { |
| 187 | #ifdef CONFIG_KMOD |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 188 | /* don't call nfnl_unlock, since it would reenter |
Harald Welte | 37d2e7a | 2005-11-14 15:24:59 -0800 | [diff] [blame] | 189 | * with further packet processing */ |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 190 | __nfnl_unlock(); |
Harald Welte | 37d2e7a | 2005-11-14 15:24:59 -0800 | [diff] [blame] | 191 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 192 | nfnl_lock(); |
Harald Welte | 37d2e7a | 2005-11-14 15:24:59 -0800 | [diff] [blame] | 193 | ss = nfnetlink_get_subsys(type); |
Harald Welte | 0ab43f8 | 2005-08-09 19:43:44 -0700 | [diff] [blame] | 194 | if (!ss) |
| 195 | #endif |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 196 | return -EINVAL; |
Harald Welte | 0ab43f8 | 2005-08-09 19:43:44 -0700 | [diff] [blame] | 197 | } |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 198 | |
| 199 | nc = nfnetlink_find_client(type, ss); |
Pablo Neira Ayuso | 67ca396 | 2007-03-14 16:40:38 -0700 | [diff] [blame] | 200 | if (!nc) |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 201 | return -EINVAL; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 202 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 203 | { |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 204 | u_int16_t attr_count = |
Harald Welte | 927ccbc | 2005-08-09 20:03:40 -0700 | [diff] [blame] | 205 | ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count; |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 206 | struct nlattr *cda[attr_count+1]; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 207 | |
Patrick McHardy | df6fb86 | 2007-09-28 14:37:03 -0700 | [diff] [blame^] | 208 | memset(cda, 0, sizeof(struct nlattr *) * attr_count); |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 209 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 210 | err = nfnetlink_check_attributes(ss, nlh, cda); |
| 211 | if (err < 0) |
Thomas Graf | 1d00a4e | 2007-03-22 23:30:12 -0700 | [diff] [blame] | 212 | return err; |
| 213 | return nc->call(nfnl, skb, nlh, cda); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 214 | } |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 215 | } |
| 216 | |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 217 | static void nfnetlink_rcv(struct sock *sk, int len) |
| 218 | { |
Patrick McHardy | 73c3618 | 2007-03-14 16:39:45 -0700 | [diff] [blame] | 219 | unsigned int qlen = 0; |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 220 | |
Patrick McHardy | 73c3618 | 2007-03-14 16:39:45 -0700 | [diff] [blame] | 221 | do { |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 222 | if (nfnl_trylock()) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 223 | return; |
Herbert Xu | 0cfad07 | 2007-09-16 16:24:44 -0700 | [diff] [blame] | 224 | qlen = netlink_run_queue(sk, qlen, nfnetlink_rcv_msg); |
Patrick McHardy | a3c5029 | 2007-03-14 16:39:25 -0700 | [diff] [blame] | 225 | __nfnl_unlock(); |
Patrick McHardy | 73c3618 | 2007-03-14 16:39:45 -0700 | [diff] [blame] | 226 | } while (qlen); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 227 | } |
| 228 | |
Adrian Bunk | 395dde2 | 2005-09-05 18:06:45 -0700 | [diff] [blame] | 229 | static void __exit nfnetlink_exit(void) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 230 | { |
| 231 | printk("Removing netfilter NETLINK layer.\n"); |
| 232 | sock_release(nfnl->sk_socket); |
| 233 | return; |
| 234 | } |
| 235 | |
Adrian Bunk | 395dde2 | 2005-09-05 18:06:45 -0700 | [diff] [blame] | 236 | static int __init nfnetlink_init(void) |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 237 | { |
| 238 | printk("Netfilter messages via NETLINK v%s.\n", nfversion); |
| 239 | |
Eric W. Biederman | b4b5102 | 2007-09-12 13:05:38 +0200 | [diff] [blame] | 240 | nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX, |
Patrick McHardy | af65bdf | 2007-04-20 14:14:21 -0700 | [diff] [blame] | 241 | nfnetlink_rcv, NULL, THIS_MODULE); |
Harald Welte | f9e815b | 2005-08-09 19:30:24 -0700 | [diff] [blame] | 242 | if (!nfnl) { |
| 243 | printk(KERN_ERR "cannot initialize nfnetlink!\n"); |
| 244 | return -1; |
| 245 | } |
| 246 | |
| 247 | return 0; |
| 248 | } |
| 249 | |
| 250 | module_init(nfnetlink_init); |
| 251 | module_exit(nfnetlink_exit); |