| /* |
| * netfilter module for userspace packet logging daemons |
| * |
| * (C) 2000-2004 by Harald Welte <laforge@netfilter.org> |
| * |
| * 2000/09/22 ulog-cprange feature added |
| * 2001/01/04 in-kernel queue as proposed by Sebastian Zander |
| * <zander@fokus.gmd.de> |
| * 2001/01/30 per-rule nlgroup conflicts with global queue. |
| * nlgroup now global (sysctl) |
| * 2001/04/19 ulog-queue reworked, now fixed buffer size specified at |
| * module loadtime -HW |
| * 2002/07/07 remove broken nflog_rcv() function -HW |
| * 2002/08/29 fix shifted/unshifted nlgroup bug -HW |
| * 2002/10/30 fix uninitialized mac_len field - <Anders K. Pedersen> |
| * 2004/10/25 fix erroneous calculation of 'len' parameter to NLMSG_PUT |
| * resulting in bogus 'error during NLMSG_PUT' messages. |
| * |
| * (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * 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. |
| * |
| * Actually you should use nlbufsiz a bit smaller than PAGE_SIZE, since |
| * nlbufsiz is used with alloc_skb, which adds another |
| * sizeof(struct skb_shared_info). Use NLMSG_GOODSIZE instead. |
| * |
| * flushtimeout: |
| * Specify, after how many hundredths of a second the queue should be |
| * flushed even if it is not full yet. |
| * |
| * ipt_ULOG.c,v 1.22 2002/10/30 09:07:31 laforge Exp |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/config.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/mm.h> |
| #include <linux/moduleparam.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv4/ipt_ULOG.h> |
| #include <net/sock.h> |
| #include <linux/bitops.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); |
| MODULE_DESCRIPTION("iptables userspace logging module"); |
| MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); |
| |
| #define ULOG_NL_EVENT 111 /* Harald's favorite number */ |
| #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ |
| |
| #if 0 |
| #define DEBUGP(format, args...) printk("%s:%s:" format, \ |
| __FILE__, __FUNCTION__ , ## args) |
| #else |
| #define DEBUGP(format, args...) |
| #endif |
| |
| #define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0) |
| |
| static unsigned int nlbufsiz = NLMSG_GOODSIZE; |
| module_param(nlbufsiz, uint, 0400); |
| MODULE_PARM_DESC(nlbufsiz, "netlink buffer size"); |
| |
| static unsigned int flushtimeout = 10; |
| module_param(flushtimeout, uint, 0600); |
| MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)"); |
| |
| static int nflog = 1; |
| module_param(nflog, bool, 0400); |
| MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); |
| |
| /* global data structures */ |
| |
| 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 */ |
| } ulog_buff_t; |
| |
| static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS]; /* array of buffers */ |
| |
| static struct sock *nflognl; /* our socket */ |
| static DEFINE_SPINLOCK(ulog_lock); /* spinlock */ |
| |
| /* send one ulog_buff_t to userspace */ |
| static void ulog_send(unsigned int nlgroupnum) |
| { |
| ulog_buff_t *ub = &ulog_buffers[nlgroupnum]; |
| |
| if (timer_pending(&ub->timer)) { |
| DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n"); |
| del_timer(&ub->timer); |
| } |
| |
| /* last nlmsg needs NLMSG_DONE */ |
| if (ub->qlen > 1) |
| ub->lastnlh->nlmsg_type = NLMSG_DONE; |
| |
| NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1; |
| DEBUGP("ipt_ULOG: throwing %d packets to netlink group %u\n", |
| ub->qlen, nlgroupnum + 1); |
| netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC); |
| |
| ub->qlen = 0; |
| ub->skb = NULL; |
| ub->lastnlh = NULL; |
| |
| } |
| |
| |
| /* timer function to flush queue in flushtimeout time */ |
| static void ulog_timer(unsigned long data) |
| { |
| DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n"); |
| |
| /* lock to protect against somebody modifying our structure |
| * from ipt_ulog_target at the same time */ |
| spin_lock_bh(&ulog_lock); |
| ulog_send(data); |
| spin_unlock_bh(&ulog_lock); |
| } |
| |
| static struct sk_buff *ulog_alloc_skb(unsigned int size) |
| { |
| struct sk_buff *skb; |
| unsigned int n; |
| |
| /* alloc skb which should be big enough for a whole |
| * multipart message. WARNING: has to be <= 131000 |
| * due to slab allocator restrictions */ |
| |
| n = max(size, nlbufsiz); |
| skb = alloc_skb(n, GFP_ATOMIC); |
| if (!skb) { |
| PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n", n); |
| |
| if (n > size) { |
| /* try to allocate only as much as we need for |
| * current packet */ |
| |
| skb = alloc_skb(size, GFP_ATOMIC); |
| if (!skb) |
| PRINTR("ipt_ULOG: can't even allocate %ub\n", |
| size); |
| } |
| } |
| |
| return skb; |
| } |
| |
| static void ipt_ulog_packet(unsigned int hooknum, |
| const struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| const struct ipt_ulog_info *loginfo, |
| const char *prefix) |
| { |
| ulog_buff_t *ub; |
| ulog_packet_msg_t *pm; |
| size_t size, copy_len; |
| struct nlmsghdr *nlh; |
| |
| /* ffs == find first bit set, necessary because userspace |
| * is already shifting groupnumber, but we need unshifted. |
| * ffs() returns [1..32], we need [0..31] */ |
| unsigned int groupnum = ffs(loginfo->nl_group) - 1; |
| |
| /* calculate the size of the skb needed */ |
| if ((loginfo->copy_range == 0) || |
| (loginfo->copy_range > skb->len)) { |
| copy_len = skb->len; |
| } else { |
| copy_len = loginfo->copy_range; |
| } |
| |
| size = NLMSG_SPACE(sizeof(*pm) + copy_len); |
| |
| ub = &ulog_buffers[groupnum]; |
| |
| spin_lock_bh(&ulog_lock); |
| |
| if (!ub->skb) { |
| if (!(ub->skb = ulog_alloc_skb(size))) |
| goto alloc_failure; |
| } else if (ub->qlen >= loginfo->qthreshold || |
| size > skb_tailroom(ub->skb)) { |
| /* either the queue len is too high or we don't have |
| * enough room in nlskb left. send it to userspace. */ |
| |
| ulog_send(groupnum); |
| |
| if (!(ub->skb = ulog_alloc_skb(size))) |
| goto alloc_failure; |
| } |
| |
| DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub->qlen, |
| loginfo->qthreshold); |
| |
| /* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */ |
| nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, |
| sizeof(*pm)+copy_len); |
| ub->qlen++; |
| |
| pm = NLMSG_DATA(nlh); |
| |
| /* We might not have a timestamp, get one */ |
| if (skb->tstamp.off_sec == 0) |
| __net_timestamp((struct sk_buff *)skb); |
| |
| /* copy hook, prefix, timestamp, payload, etc. */ |
| pm->data_len = copy_len; |
| pm->timestamp_sec = skb->tstamp.off_sec; |
| pm->timestamp_usec = skb->tstamp.off_usec; |
| pm->mark = skb->nfmark; |
| pm->hook = hooknum; |
| if (prefix != NULL) |
| strncpy(pm->prefix, prefix, sizeof(pm->prefix)); |
| else if (loginfo->prefix[0] != '\0') |
| strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); |
| else |
| *(pm->prefix) = '\0'; |
| |
| if (in && in->hard_header_len > 0 |
| && skb->mac.raw != (void *) skb->nh.iph |
| && in->hard_header_len <= ULOG_MAC_LEN) { |
| memcpy(pm->mac, skb->mac.raw, in->hard_header_len); |
| pm->mac_len = in->hard_header_len; |
| } else |
| pm->mac_len = 0; |
| |
| if (in) |
| strncpy(pm->indev_name, in->name, sizeof(pm->indev_name)); |
| else |
| pm->indev_name[0] = '\0'; |
| |
| if (out) |
| strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name)); |
| else |
| pm->outdev_name[0] = '\0'; |
| |
| /* copy_len <= skb->len, so can't fail. */ |
| if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0) |
| BUG(); |
| |
| /* check if we are building multi-part messages */ |
| if (ub->qlen > 1) { |
| ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; |
| } |
| |
| ub->lastnlh = nlh; |
| |
| /* if timer isn't already running, start it */ |
| if (!timer_pending(&ub->timer)) { |
| ub->timer.expires = jiffies + flushtimeout * HZ / 100; |
| add_timer(&ub->timer); |
| } |
| |
| /* if threshold is reached, send message to userspace */ |
| if (ub->qlen >= loginfo->qthreshold) { |
| if (loginfo->qthreshold > 1) |
| nlh->nlmsg_type = NLMSG_DONE; |
| ulog_send(groupnum); |
| } |
| |
| spin_unlock_bh(&ulog_lock); |
| |
| return; |
| |
| nlmsg_failure: |
| PRINTR("ipt_ULOG: error during NLMSG_PUT\n"); |
| |
| alloc_failure: |
| PRINTR("ipt_ULOG: Error building netlink message\n"); |
| |
| spin_unlock_bh(&ulog_lock); |
| } |
| |
| static unsigned int ipt_ulog_target(struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| unsigned int hooknum, |
| const void *targinfo, void *userinfo) |
| { |
| struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; |
| |
| ipt_ulog_packet(hooknum, *pskb, in, out, loginfo, NULL); |
| |
| return IPT_CONTINUE; |
| } |
| |
| static void ipt_logfn(unsigned int 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 ipt_ulog_info loginfo; |
| |
| if (!li || li->type != NF_LOG_TYPE_ULOG) { |
| loginfo.nl_group = ULOG_DEFAULT_NLGROUP; |
| loginfo.copy_range = 0; |
| loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD; |
| loginfo.prefix[0] = '\0'; |
| } else { |
| loginfo.nl_group = li->u.ulog.group; |
| loginfo.copy_range = li->u.ulog.copy_len; |
| loginfo.qthreshold = li->u.ulog.qthreshold; |
| strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); |
| } |
| |
| ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); |
| } |
| |
| static int ipt_ulog_checkentry(const char *tablename, |
| const void *e, |
| void *targinfo, |
| unsigned int targinfosize, |
| unsigned int hookmask) |
| { |
| struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; |
| |
| if (targinfosize != IPT_ALIGN(sizeof(struct ipt_ulog_info))) { |
| DEBUGP("ipt_ULOG: targinfosize %u != 0\n", targinfosize); |
| return 0; |
| } |
| |
| if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') { |
| DEBUGP("ipt_ULOG: prefix term %i\n", |
| loginfo->prefix[sizeof(loginfo->prefix) - 1]); |
| return 0; |
| } |
| |
| if (loginfo->qthreshold > ULOG_MAX_QLEN) { |
| DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n", |
| loginfo->qthreshold); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static struct ipt_target ipt_ulog_reg = { |
| .name = "ULOG", |
| .target = ipt_ulog_target, |
| .checkentry = ipt_ulog_checkentry, |
| .me = THIS_MODULE, |
| }; |
| |
| static struct nf_logger ipt_ulog_logger = { |
| .name = "ipt_ULOG", |
| .logfn = &ipt_logfn, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init init(void) |
| { |
| int i; |
| |
| DEBUGP("ipt_ULOG: init module\n"); |
| |
| if (nlbufsiz > 128*1024) { |
| printk("Netlink buffer has to be <= 128kB\n"); |
| return -EINVAL; |
| } |
| |
| /* initialize ulog_buffers */ |
| for (i = 0; i < ULOG_MAXNLGROUPS; i++) { |
| init_timer(&ulog_buffers[i].timer); |
| ulog_buffers[i].timer.function = ulog_timer; |
| ulog_buffers[i].timer.data = i; |
| } |
| |
| nflognl = netlink_kernel_create(NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL, |
| THIS_MODULE); |
| if (!nflognl) |
| return -ENOMEM; |
| |
| if (ipt_register_target(&ipt_ulog_reg) != 0) { |
| sock_release(nflognl->sk_socket); |
| return -EINVAL; |
| } |
| if (nflog) |
| nf_log_register(PF_INET, &ipt_ulog_logger); |
| |
| return 0; |
| } |
| |
| static void __exit fini(void) |
| { |
| ulog_buff_t *ub; |
| int i; |
| |
| DEBUGP("ipt_ULOG: cleanup_module\n"); |
| |
| if (nflog) |
| nf_log_unregister_logger(&ipt_ulog_logger); |
| ipt_unregister_target(&ipt_ulog_reg); |
| sock_release(nflognl->sk_socket); |
| |
| /* remove pending timers and free allocated skb's */ |
| for (i = 0; i < ULOG_MAXNLGROUPS; i++) { |
| ub = &ulog_buffers[i]; |
| if (timer_pending(&ub->timer)) { |
| DEBUGP("timer was pending, deleting\n"); |
| del_timer(&ub->timer); |
| } |
| |
| if (ub->skb) { |
| kfree_skb(ub->skb); |
| ub->skb = NULL; |
| } |
| } |
| |
| } |
| |
| module_init(init); |
| module_exit(fini); |