| /* |
| * netfilter module for userspace bridged Ethernet frames logging daemons |
| * |
| * Authors: |
| * Bart De Schuymer <bdschuym@pandora.be> |
| * Harald Welte <laforge@netfilter.org> |
| * |
| * November, 2004 |
| * |
| * Based on ipt_ULOG.c, which is |
| * (C) 2000-2002 by Harald Welte <laforge@netfilter.org> |
| * |
| * This module accepts two parameters: |
| * |
| * nlbufsiz: |
| * The parameter specifies how big the buffer for each netlink multicast |
| * group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will |
| * get accumulated in the kernel until they are sent to userspace. It is |
| * NOT possible to allocate more than 128kB, and it is strongly discouraged, |
| * because atomically allocating 128kB inside the network rx softirq is not |
| * reliable. Please also keep in mind that this buffer size is allocated for |
| * each nlgroup you are using, so the total kernel memory usage increases |
| * by that factor. |
| * |
| * flushtimeout: |
| * Specify, after how many hundredths of a second the queue should be |
| * flushed even if it is not full yet. |
| * |
| */ |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/socket.h> |
| #include <linux/skbuff.h> |
| #include <linux/kernel.h> |
| #include <linux/timer.h> |
| #include <linux/netlink.h> |
| #include <linux/netdevice.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_bridge/ebtables.h> |
| #include <linux/netfilter_bridge/ebt_ulog.h> |
| #include <net/netfilter/nf_log.h> |
| #include <net/sock.h> |
| #include "../br_private.h" |
| |
| static unsigned int nlbufsiz = NLMSG_GOODSIZE; |
| module_param(nlbufsiz, uint, 0600); |
| MODULE_PARM_DESC(nlbufsiz, "netlink buffer size (number of bytes) " |
| "(defaults to 4096)"); |
| |
| static unsigned int flushtimeout = 10; |
| module_param(flushtimeout, uint, 0600); |
| MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths ofa second) " |
| "(defaults to 10)"); |
| |
| typedef struct { |
| unsigned int qlen; /* number of nlmsgs' in the skb */ |
| struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ |
| struct sk_buff *skb; /* the pre-allocated skb */ |
| struct timer_list timer; /* the timer function */ |
| spinlock_t lock; /* the per-queue lock */ |
| } ebt_ulog_buff_t; |
| |
| static ebt_ulog_buff_t ulog_buffers[EBT_ULOG_MAXNLGROUPS]; |
| static struct sock *ebtulognl; |
| |
| /* send one ulog_buff_t to userspace */ |
| static void ulog_send(unsigned int nlgroup) |
| { |
| ebt_ulog_buff_t *ub = &ulog_buffers[nlgroup]; |
| |
| if (timer_pending(&ub->timer)) |
| del_timer(&ub->timer); |
| |
| if (!ub->skb) |
| return; |
| |
| /* last nlmsg needs NLMSG_DONE */ |
| if (ub->qlen > 1) |
| ub->lastnlh->nlmsg_type = NLMSG_DONE; |
| |
| NETLINK_CB(ub->skb).dst_group = nlgroup + 1; |
| netlink_broadcast(ebtulognl, ub->skb, 0, nlgroup + 1, GFP_ATOMIC); |
| |
| ub->qlen = 0; |
| ub->skb = NULL; |
| } |
| |
| /* timer function to flush queue in flushtimeout time */ |
| static void ulog_timer(unsigned long data) |
| { |
| spin_lock_bh(&ulog_buffers[data].lock); |
| if (ulog_buffers[data].skb) |
| ulog_send(data); |
| spin_unlock_bh(&ulog_buffers[data].lock); |
| } |
| |
| static struct sk_buff *ulog_alloc_skb(unsigned int size) |
| { |
| struct sk_buff *skb; |
| unsigned int n; |
| |
| n = max(size, nlbufsiz); |
| skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN); |
| if (!skb) { |
| if (n > size) { |
| /* try to allocate only as much as we need for |
| * current packet */ |
| skb = alloc_skb(size, GFP_ATOMIC); |
| if (!skb) |
| pr_debug("cannot even allocate buffer of size %ub\n", |
| size); |
| } |
| } |
| |
| return skb; |
| } |
| |
| static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb, |
| const struct net_device *in, const struct net_device *out, |
| const struct ebt_ulog_info *uloginfo, const char *prefix) |
| { |
| ebt_ulog_packet_msg_t *pm; |
| size_t size, copy_len; |
| struct nlmsghdr *nlh; |
| unsigned int group = uloginfo->nlgroup; |
| ebt_ulog_buff_t *ub = &ulog_buffers[group]; |
| spinlock_t *lock = &ub->lock; |
| ktime_t kt; |
| |
| if ((uloginfo->cprange == 0) || |
| (uloginfo->cprange > skb->len + ETH_HLEN)) |
| copy_len = skb->len + ETH_HLEN; |
| else |
| copy_len = uloginfo->cprange; |
| |
| size = NLMSG_SPACE(sizeof(*pm) + copy_len); |
| if (size > nlbufsiz) { |
| pr_debug("Size %Zd needed, but nlbufsiz=%d\n", size, nlbufsiz); |
| return; |
| } |
| |
| spin_lock_bh(lock); |
| |
| if (!ub->skb) { |
| if (!(ub->skb = ulog_alloc_skb(size))) |
| goto alloc_failure; |
| } else if (size > skb_tailroom(ub->skb)) { |
| ulog_send(group); |
| |
| if (!(ub->skb = ulog_alloc_skb(size))) |
| goto alloc_failure; |
| } |
| |
| nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, 0, |
| size - NLMSG_ALIGN(sizeof(*nlh))); |
| ub->qlen++; |
| |
| pm = NLMSG_DATA(nlh); |
| |
| /* Fill in the ulog data */ |
| pm->version = EBT_ULOG_VERSION; |
| kt = ktime_get_real(); |
| pm->stamp = ktime_to_timeval(kt); |
| if (ub->qlen == 1) |
| ub->skb->tstamp = kt; |
| pm->data_len = copy_len; |
| pm->mark = skb->mark; |
| pm->hook = hooknr; |
| if (uloginfo->prefix != NULL) |
| strcpy(pm->prefix, uloginfo->prefix); |
| else |
| *(pm->prefix) = '\0'; |
| |
| if (in) { |
| strcpy(pm->physindev, in->name); |
| /* If in isn't a bridge, then physindev==indev */ |
| if (br_port_exists(in)) |
| /* rcu_read_lock()ed by nf_hook_slow */ |
| strcpy(pm->indev, br_port_get_rcu(in)->br->dev->name); |
| else |
| strcpy(pm->indev, in->name); |
| } else |
| pm->indev[0] = pm->physindev[0] = '\0'; |
| |
| if (out) { |
| /* If out exists, then out is a bridge port */ |
| strcpy(pm->physoutdev, out->name); |
| /* rcu_read_lock()ed by nf_hook_slow */ |
| strcpy(pm->outdev, br_port_get_rcu(out)->br->dev->name); |
| } else |
| pm->outdev[0] = pm->physoutdev[0] = '\0'; |
| |
| if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0) |
| BUG(); |
| |
| if (ub->qlen > 1) |
| ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; |
| |
| ub->lastnlh = nlh; |
| |
| if (ub->qlen >= uloginfo->qthreshold) |
| ulog_send(group); |
| else if (!timer_pending(&ub->timer)) { |
| ub->timer.expires = jiffies + flushtimeout * HZ / 100; |
| add_timer(&ub->timer); |
| } |
| |
| unlock: |
| spin_unlock_bh(lock); |
| |
| return; |
| |
| nlmsg_failure: |
| pr_debug("error during NLMSG_PUT. This should " |
| "not happen, please report to author.\n"); |
| alloc_failure: |
| goto unlock; |
| } |
| |
| /* this function is registered with the netfilter core */ |
| static void ebt_log_packet(u_int8_t pf, unsigned int hooknum, |
| const struct sk_buff *skb, const struct net_device *in, |
| const struct net_device *out, const struct nf_loginfo *li, |
| const char *prefix) |
| { |
| struct ebt_ulog_info loginfo; |
| |
| if (!li || li->type != NF_LOG_TYPE_ULOG) { |
| loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP; |
| loginfo.cprange = 0; |
| loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD; |
| loginfo.prefix[0] = '\0'; |
| } else { |
| loginfo.nlgroup = li->u.ulog.group; |
| loginfo.cprange = li->u.ulog.copy_len; |
| loginfo.qthreshold = li->u.ulog.qthreshold; |
| strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); |
| } |
| |
| ebt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); |
| } |
| |
| static unsigned int |
| ebt_ulog_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| { |
| ebt_ulog_packet(par->hooknum, skb, par->in, par->out, |
| par->targinfo, NULL); |
| return EBT_CONTINUE; |
| } |
| |
| static int ebt_ulog_tg_check(const struct xt_tgchk_param *par) |
| { |
| struct ebt_ulog_info *uloginfo = par->targinfo; |
| |
| if (uloginfo->nlgroup > 31) |
| return -EINVAL; |
| |
| uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0'; |
| |
| if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN) |
| uloginfo->qthreshold = EBT_ULOG_MAX_QLEN; |
| |
| return 0; |
| } |
| |
| static struct xt_target ebt_ulog_tg_reg __read_mostly = { |
| .name = "ulog", |
| .revision = 0, |
| .family = NFPROTO_BRIDGE, |
| .target = ebt_ulog_tg, |
| .checkentry = ebt_ulog_tg_check, |
| .targetsize = sizeof(struct ebt_ulog_info), |
| .me = THIS_MODULE, |
| }; |
| |
| static struct nf_logger ebt_ulog_logger __read_mostly = { |
| .name = "ebt_ulog", |
| .logfn = &ebt_log_packet, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init ebt_ulog_init(void) |
| { |
| int ret; |
| int i; |
| |
| if (nlbufsiz >= 128*1024) { |
| pr_warning("Netlink buffer has to be <= 128kB," |
| " please try a smaller nlbufsiz parameter.\n"); |
| return -EINVAL; |
| } |
| |
| /* initialize ulog_buffers */ |
| for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) { |
| setup_timer(&ulog_buffers[i].timer, ulog_timer, i); |
| spin_lock_init(&ulog_buffers[i].lock); |
| } |
| |
| ebtulognl = netlink_kernel_create(&init_net, NETLINK_NFLOG, |
| EBT_ULOG_MAXNLGROUPS, NULL, NULL, |
| THIS_MODULE); |
| if (!ebtulognl) |
| ret = -ENOMEM; |
| else if ((ret = xt_register_target(&ebt_ulog_tg_reg)) != 0) |
| netlink_kernel_release(ebtulognl); |
| |
| if (ret == 0) |
| nf_log_register(NFPROTO_BRIDGE, &ebt_ulog_logger); |
| |
| return ret; |
| } |
| |
| static void __exit ebt_ulog_fini(void) |
| { |
| ebt_ulog_buff_t *ub; |
| int i; |
| |
| nf_log_unregister(&ebt_ulog_logger); |
| xt_unregister_target(&ebt_ulog_tg_reg); |
| for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) { |
| ub = &ulog_buffers[i]; |
| if (timer_pending(&ub->timer)) |
| del_timer(&ub->timer); |
| spin_lock_bh(&ub->lock); |
| if (ub->skb) { |
| kfree_skb(ub->skb); |
| ub->skb = NULL; |
| } |
| spin_unlock_bh(&ub->lock); |
| } |
| netlink_kernel_release(ebtulognl); |
| } |
| |
| module_init(ebt_ulog_init); |
| module_exit(ebt_ulog_fini); |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>"); |
| MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG"); |