Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * netfilter module for userspace bridged Ethernet frames logging daemons |
| 3 | * |
| 4 | * Authors: |
| 5 | * Bart De Schuymer <bdschuym@pandora.be> |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 6 | * Harald Welte <laforge@netfilter.org> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * |
| 8 | * November, 2004 |
| 9 | * |
| 10 | * Based on ipt_ULOG.c, which is |
| 11 | * (C) 2000-2002 by Harald Welte <laforge@netfilter.org> |
| 12 | * |
| 13 | * This module accepts two parameters: |
| 14 | * |
| 15 | * nlbufsiz: |
| 16 | * The parameter specifies how big the buffer for each netlink multicast |
| 17 | * group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will |
| 18 | * get accumulated in the kernel until they are sent to userspace. It is |
| 19 | * NOT possible to allocate more than 128kB, and it is strongly discouraged, |
| 20 | * because atomically allocating 128kB inside the network rx softirq is not |
| 21 | * reliable. Please also keep in mind that this buffer size is allocated for |
| 22 | * each nlgroup you are using, so the total kernel memory usage increases |
| 23 | * by that factor. |
| 24 | * |
| 25 | * flushtimeout: |
| 26 | * Specify, after how many hundredths of a second the queue should be |
| 27 | * flushed even if it is not full yet. |
| 28 | * |
| 29 | */ |
| 30 | |
| 31 | #include <linux/module.h> |
| 32 | #include <linux/config.h> |
| 33 | #include <linux/spinlock.h> |
| 34 | #include <linux/socket.h> |
| 35 | #include <linux/skbuff.h> |
| 36 | #include <linux/kernel.h> |
| 37 | #include <linux/timer.h> |
| 38 | #include <linux/netlink.h> |
| 39 | #include <linux/netdevice.h> |
| 40 | #include <linux/module.h> |
| 41 | #include <linux/netfilter_bridge/ebtables.h> |
| 42 | #include <linux/netfilter_bridge/ebt_ulog.h> |
| 43 | #include <net/sock.h> |
| 44 | #include "../br_private.h" |
| 45 | |
| 46 | #define PRINTR(format, args...) do { if (net_ratelimit()) \ |
| 47 | printk(format , ## args); } while (0) |
| 48 | |
| 49 | static unsigned int nlbufsiz = 4096; |
| 50 | module_param(nlbufsiz, uint, 0600); |
| 51 | MODULE_PARM_DESC(nlbufsiz, "netlink buffer size (number of bytes) " |
| 52 | "(defaults to 4096)"); |
| 53 | |
| 54 | static unsigned int flushtimeout = 10; |
| 55 | module_param(flushtimeout, uint, 0600); |
| 56 | MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths ofa second) " |
| 57 | "(defaults to 10)"); |
| 58 | |
| 59 | typedef struct { |
| 60 | unsigned int qlen; /* number of nlmsgs' in the skb */ |
| 61 | struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ |
| 62 | struct sk_buff *skb; /* the pre-allocated skb */ |
| 63 | struct timer_list timer; /* the timer function */ |
| 64 | spinlock_t lock; /* the per-queue lock */ |
| 65 | } ebt_ulog_buff_t; |
| 66 | |
| 67 | static ebt_ulog_buff_t ulog_buffers[EBT_ULOG_MAXNLGROUPS]; |
| 68 | static struct sock *ebtulognl; |
| 69 | |
| 70 | /* send one ulog_buff_t to userspace */ |
| 71 | static void ulog_send(unsigned int nlgroup) |
| 72 | { |
| 73 | ebt_ulog_buff_t *ub = &ulog_buffers[nlgroup]; |
| 74 | |
| 75 | if (timer_pending(&ub->timer)) |
| 76 | del_timer(&ub->timer); |
| 77 | |
| 78 | /* last nlmsg needs NLMSG_DONE */ |
| 79 | if (ub->qlen > 1) |
| 80 | ub->lastnlh->nlmsg_type = NLMSG_DONE; |
| 81 | |
Patrick McHardy | ac6d439 | 2005-08-14 19:29:52 -0700 | [diff] [blame] | 82 | NETLINK_CB(ub->skb).dst_group = nlgroup + 1; |
| 83 | netlink_broadcast(ebtulognl, ub->skb, 0, nlgroup + 1, GFP_ATOMIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
| 85 | ub->qlen = 0; |
| 86 | ub->skb = NULL; |
| 87 | } |
| 88 | |
| 89 | /* timer function to flush queue in flushtimeout time */ |
| 90 | static void ulog_timer(unsigned long data) |
| 91 | { |
| 92 | spin_lock_bh(&ulog_buffers[data].lock); |
| 93 | if (ulog_buffers[data].skb) |
| 94 | ulog_send(data); |
| 95 | spin_unlock_bh(&ulog_buffers[data].lock); |
| 96 | } |
| 97 | |
| 98 | static struct sk_buff *ulog_alloc_skb(unsigned int size) |
| 99 | { |
| 100 | struct sk_buff *skb; |
| 101 | |
| 102 | skb = alloc_skb(nlbufsiz, GFP_ATOMIC); |
| 103 | if (!skb) { |
| 104 | PRINTR(KERN_ERR "ebt_ulog: can't alloc whole buffer " |
| 105 | "of size %ub!\n", nlbufsiz); |
| 106 | if (size < nlbufsiz) { |
| 107 | /* try to allocate only as much as we need for |
| 108 | * current packet */ |
| 109 | skb = alloc_skb(size, GFP_ATOMIC); |
| 110 | if (!skb) |
| 111 | PRINTR(KERN_ERR "ebt_ulog: can't even allocate " |
| 112 | "buffer of size %ub\n", size); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | return skb; |
| 117 | } |
| 118 | |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 119 | static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | const struct net_device *in, const struct net_device *out, |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 121 | const struct ebt_ulog_info *uloginfo, const char *prefix) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | { |
| 123 | ebt_ulog_packet_msg_t *pm; |
| 124 | size_t size, copy_len; |
| 125 | struct nlmsghdr *nlh; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | unsigned int group = uloginfo->nlgroup; |
| 127 | ebt_ulog_buff_t *ub = &ulog_buffers[group]; |
| 128 | spinlock_t *lock = &ub->lock; |
| 129 | |
| 130 | if ((uloginfo->cprange == 0) || |
| 131 | (uloginfo->cprange > skb->len + ETH_HLEN)) |
| 132 | copy_len = skb->len + ETH_HLEN; |
| 133 | else |
| 134 | copy_len = uloginfo->cprange; |
| 135 | |
| 136 | size = NLMSG_SPACE(sizeof(*pm) + copy_len); |
| 137 | if (size > nlbufsiz) { |
| 138 | PRINTR("ebt_ulog: Size %Zd needed, but nlbufsiz=%d\n", |
| 139 | size, nlbufsiz); |
| 140 | return; |
| 141 | } |
| 142 | |
| 143 | spin_lock_bh(lock); |
| 144 | |
| 145 | if (!ub->skb) { |
| 146 | if (!(ub->skb = ulog_alloc_skb(size))) |
| 147 | goto alloc_failure; |
| 148 | } else if (size > skb_tailroom(ub->skb)) { |
| 149 | ulog_send(group); |
| 150 | |
| 151 | if (!(ub->skb = ulog_alloc_skb(size))) |
| 152 | goto alloc_failure; |
| 153 | } |
| 154 | |
| 155 | nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, 0, |
| 156 | size - NLMSG_ALIGN(sizeof(*nlh))); |
| 157 | ub->qlen++; |
| 158 | |
| 159 | pm = NLMSG_DATA(nlh); |
| 160 | |
| 161 | /* Fill in the ulog data */ |
| 162 | pm->version = EBT_ULOG_VERSION; |
| 163 | do_gettimeofday(&pm->stamp); |
| 164 | if (ub->qlen == 1) |
Patrick McHardy | a61bbcf | 2005-08-14 17:24:31 -0700 | [diff] [blame] | 165 | skb_set_timestamp(ub->skb, &pm->stamp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | pm->data_len = copy_len; |
| 167 | pm->mark = skb->nfmark; |
| 168 | pm->hook = hooknr; |
| 169 | if (uloginfo->prefix != NULL) |
| 170 | strcpy(pm->prefix, uloginfo->prefix); |
| 171 | else |
| 172 | *(pm->prefix) = '\0'; |
| 173 | |
| 174 | if (in) { |
| 175 | strcpy(pm->physindev, in->name); |
| 176 | /* If in isn't a bridge, then physindev==indev */ |
| 177 | if (in->br_port) |
| 178 | strcpy(pm->indev, in->br_port->br->dev->name); |
| 179 | else |
| 180 | strcpy(pm->indev, in->name); |
| 181 | } else |
| 182 | pm->indev[0] = pm->physindev[0] = '\0'; |
| 183 | |
| 184 | if (out) { |
| 185 | /* If out exists, then out is a bridge port */ |
| 186 | strcpy(pm->physoutdev, out->name); |
| 187 | strcpy(pm->outdev, out->br_port->br->dev->name); |
| 188 | } else |
| 189 | pm->outdev[0] = pm->physoutdev[0] = '\0'; |
| 190 | |
| 191 | if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0) |
| 192 | BUG(); |
| 193 | |
| 194 | if (ub->qlen > 1) |
| 195 | ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; |
| 196 | |
| 197 | ub->lastnlh = nlh; |
| 198 | |
| 199 | if (ub->qlen >= uloginfo->qthreshold) |
| 200 | ulog_send(group); |
| 201 | else if (!timer_pending(&ub->timer)) { |
| 202 | ub->timer.expires = jiffies + flushtimeout * HZ / 100; |
| 203 | add_timer(&ub->timer); |
| 204 | } |
| 205 | |
| 206 | unlock: |
| 207 | spin_unlock_bh(lock); |
| 208 | |
| 209 | return; |
| 210 | |
| 211 | nlmsg_failure: |
| 212 | printk(KERN_CRIT "ebt_ulog: error during NLMSG_PUT. This should " |
| 213 | "not happen, please report to author.\n"); |
| 214 | goto unlock; |
| 215 | alloc_failure: |
| 216 | goto unlock; |
| 217 | } |
| 218 | |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 219 | /* this function is registered with the netfilter core */ |
| 220 | static void ebt_log_packet(unsigned int pf, unsigned int hooknum, |
| 221 | const struct sk_buff *skb, const struct net_device *in, |
| 222 | const struct net_device *out, const struct nf_loginfo *li, |
| 223 | const char *prefix) |
| 224 | { |
| 225 | struct ebt_ulog_info loginfo; |
| 226 | |
| 227 | if (!li || li->type != NF_LOG_TYPE_ULOG) { |
| 228 | loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP; |
| 229 | loginfo.cprange = 0; |
| 230 | loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD; |
| 231 | loginfo.prefix[0] = '\0'; |
| 232 | } else { |
| 233 | loginfo.nlgroup = li->u.ulog.group; |
| 234 | loginfo.cprange = li->u.ulog.copy_len; |
| 235 | loginfo.qthreshold = li->u.ulog.qthreshold; |
| 236 | strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); |
| 237 | } |
| 238 | |
| 239 | ebt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); |
| 240 | } |
| 241 | |
| 242 | static void ebt_ulog(const struct sk_buff *skb, unsigned int hooknr, |
| 243 | const struct net_device *in, const struct net_device *out, |
| 244 | const void *data, unsigned int datalen) |
| 245 | { |
| 246 | struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data; |
| 247 | |
| 248 | ebt_ulog_packet(hooknr, skb, in, out, uloginfo, NULL); |
| 249 | } |
| 250 | |
| 251 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | static int ebt_ulog_check(const char *tablename, unsigned int hookmask, |
| 253 | const struct ebt_entry *e, void *data, unsigned int datalen) |
| 254 | { |
| 255 | struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data; |
| 256 | |
| 257 | if (datalen != EBT_ALIGN(sizeof(struct ebt_ulog_info)) || |
| 258 | uloginfo->nlgroup > 31) |
| 259 | return -EINVAL; |
| 260 | |
| 261 | uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0'; |
| 262 | |
| 263 | if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN) |
| 264 | uloginfo->qthreshold = EBT_ULOG_MAX_QLEN; |
| 265 | |
| 266 | return 0; |
| 267 | } |
| 268 | |
| 269 | static struct ebt_watcher ulog = { |
| 270 | .name = EBT_ULOG_WATCHER, |
| 271 | .watcher = ebt_ulog, |
| 272 | .check = ebt_ulog_check, |
| 273 | .me = THIS_MODULE, |
| 274 | }; |
| 275 | |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 276 | static struct nf_logger ebt_ulog_logger = { |
| 277 | .name = EBT_ULOG_WATCHER, |
| 278 | .logfn = &ebt_log_packet, |
| 279 | .me = THIS_MODULE, |
| 280 | }; |
| 281 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | static int __init init(void) |
| 283 | { |
| 284 | int i, ret = 0; |
| 285 | |
| 286 | if (nlbufsiz >= 128*1024) { |
| 287 | printk(KERN_NOTICE "ebt_ulog: Netlink buffer has to be <= 128kB," |
| 288 | " please try a smaller nlbufsiz parameter.\n"); |
| 289 | return -EINVAL; |
| 290 | } |
| 291 | |
| 292 | /* initialize ulog_buffers */ |
| 293 | for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) { |
| 294 | init_timer(&ulog_buffers[i].timer); |
| 295 | ulog_buffers[i].timer.function = ulog_timer; |
| 296 | ulog_buffers[i].timer.data = i; |
| 297 | spin_lock_init(&ulog_buffers[i].lock); |
| 298 | } |
| 299 | |
Patrick McHardy | 0662860 | 2005-08-15 12:33:26 -0700 | [diff] [blame] | 300 | ebtulognl = netlink_kernel_create(NETLINK_NFLOG, EBT_ULOG_MAXNLGROUPS, |
| 301 | NULL, THIS_MODULE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | if (!ebtulognl) |
| 303 | ret = -ENOMEM; |
| 304 | else if ((ret = ebt_register_watcher(&ulog))) |
| 305 | sock_release(ebtulognl->sk_socket); |
| 306 | |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 307 | if (nf_log_register(PF_BRIDGE, &ebt_ulog_logger) < 0) { |
| 308 | printk(KERN_WARNING "ebt_ulog: not logging via ulog " |
| 309 | "since somebody else already registered for PF_BRIDGE\n"); |
| 310 | /* we cannot make module load fail here, since otherwise |
| 311 | * ebtables userspace would abort */ |
| 312 | } |
| 313 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | return ret; |
| 315 | } |
| 316 | |
| 317 | static void __exit fini(void) |
| 318 | { |
| 319 | ebt_ulog_buff_t *ub; |
| 320 | int i; |
| 321 | |
Bart De Schuymer | d5228a4 | 2005-12-13 23:14:08 -0800 | [diff] [blame^] | 322 | nf_log_unregister_logger(&ebt_ulog_logger); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | ebt_unregister_watcher(&ulog); |
| 324 | for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) { |
| 325 | ub = &ulog_buffers[i]; |
| 326 | if (timer_pending(&ub->timer)) |
| 327 | del_timer(&ub->timer); |
| 328 | spin_lock_bh(&ub->lock); |
| 329 | if (ub->skb) { |
| 330 | kfree_skb(ub->skb); |
| 331 | ub->skb = NULL; |
| 332 | } |
| 333 | spin_unlock_bh(&ub->lock); |
| 334 | } |
| 335 | sock_release(ebtulognl->sk_socket); |
| 336 | } |
| 337 | |
| 338 | module_init(init); |
| 339 | module_exit(fini); |
| 340 | MODULE_LICENSE("GPL"); |
| 341 | MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>"); |
| 342 | MODULE_DESCRIPTION("ebtables userspace logging module for bridged Ethernet" |
| 343 | " frames"); |