[NETFILTER]: Extend netfilter logging API

This patch is in preparation to nfnetlink_log:
- loggers now have to register struct nf_logger instead of nf_logfn
- nf_log_unregister() replaced by nf_log_unregister_pf() and
nf_log_unregister_logger()
- add comment to ip[6]t_LOG.h to assure nobody redefines flags
- add /proc/net/netfilter/nf_log to tell user which logger is currently
registered for which address family
- if user has configured logging, but no logging backend (logger) is
available, always spit a message to syslog, not just the first time.
- split ip[6]t_LOG.c into two parts:
Backend: Always try to register as logger for the respective address family
Frontend: Always log via nf_log_packet() API
- modify all users of nf_log_packet() to accomodate additional argument

Signed-off-by: Harald Welte <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/netfilter.h

···
 
 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
 
-typedef void nf_logfn(unsigned int hooknum,
+/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
+ * disappear once iptables is replaced with pkttables.  Please DO NOT use them
+ * for any new code! */
+#define NF_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
+#define NF_LOG_TCPOPT		0x02	/* Log TCP options */
+#define NF_LOG_IPOPT		0x04	/* Log IP options */
+#define NF_LOG_UID		0x08	/* Log UID owning local socket */
+#define NF_LOG_MASK		0x0f
+
+#define NF_LOG_TYPE_LOG		0x01
+#define NF_LOG_TYPE_ULOG	0x02
+
+struct nf_loginfo {
+	u_int8_t type;
+	union {
+		struct {
+			u_int32_t copy_len;
+			u_int16_t group;
+			u_int16_t qthreshold;
+		} ulog;
+		struct {
+			u_int8_t level;
+			u_int8_t logflags;
+		} log;
+	} u;
+};
+
+typedef void nf_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 nf_logger {
+	struct module	*me;
+	nf_logfn 	*logfn;
+	char		*name;
+};
+
 /* Function to register/unregister log function. */
-int nf_log_register(int pf, nf_logfn *logfn);
-void nf_log_unregister(int pf, nf_logfn *logfn);
+int nf_log_register(int pf, struct nf_logger *logger);
+void nf_log_unregister_pf(int pf);
+void nf_log_unregister_logger(struct nf_logger *logger);
 
 /* Calls the registered backend logging function */
 void nf_log_packet(int pf,
···
 		   const struct sk_buff *skb,
 		   const struct net_device *in,
 		   const struct net_device *out,
+		   struct nf_loginfo *li,
 		   const char *fmt, ...);
                    
 /* Activate hook; either okfn or kfree_skb called, unless a hook
···
 
 extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
 extern int nf_unregister_queue_rerouter(int pf);
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+extern struct proc_dir_entry *proc_net_netfilter;
+#endif
 
 #else /* !CONFIG_NETFILTER */
 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)

include/linux/netfilter_ipv4/ipt_LOG.h

···
 #ifndef _IPT_LOG_H
 #define _IPT_LOG_H
 
+/* make sure not to change this without changing netfilter.h:NF_LOG_* (!) */
 #define IPT_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
 #define IPT_LOG_TCPOPT		0x02	/* Log TCP options */
 #define IPT_LOG_IPOPT		0x04	/* Log IP options */

include/linux/netfilter_ipv6/ip6t_LOG.h

···
 #ifndef _IP6T_LOG_H
 #define _IP6T_LOG_H
 
+/* make sure not to change this without changing netfilter.h:NF_LOG_* (!) */
 #define IP6T_LOG_TCPSEQ		0x01	/* Log TCP sequence numbers */
 #define IP6T_LOG_TCPOPT		0x02	/* Log TCP options */
 #define IP6T_LOG_IPOPT		0x04	/* Log IP options */

net/core/netfilter.c

···
 #include <linux/if.h>
 #include <linux/netdevice.h>
 #include <linux/inetdevice.h>
+#include <linux/proc_fs.h>
 #include <net/sock.h>
 
 /* In this code, we can be waiting indefinitely for userspace to
···
 
 #define NF_LOG_PREFIXLEN		128
 
-static nf_logfn *nf_logging[NPROTO]; /* = NULL */
-static int reported = 0;
+static struct nf_logger *nf_logging[NPROTO]; /* = NULL */
 static DEFINE_SPINLOCK(nf_log_lock);
 
-int nf_log_register(int pf, nf_logfn *logfn)
+int nf_log_register(int pf, struct nf_logger *logger)
 {
 	int ret = -EBUSY;
 
···
 	 * substituting pointer. */
 	spin_lock(&nf_log_lock);
 	if (!nf_logging[pf]) {
-		rcu_assign_pointer(nf_logging[pf], logfn);
+		rcu_assign_pointer(nf_logging[pf], logger);
 		ret = 0;
 	}
 	spin_unlock(&nf_log_lock);
 	return ret;
 }		
 
-void nf_log_unregister(int pf, nf_logfn *logfn)
+void nf_log_unregister_pf(int pf)
 {
 	spin_lock(&nf_log_lock);
-	if (nf_logging[pf] == logfn)
-		nf_logging[pf] = NULL;
+	nf_logging[pf] = NULL;
 	spin_unlock(&nf_log_lock);
 
 	/* Give time to concurrent readers. */
 	synchronize_net();
-}		
+}
+
+void nf_log_unregister_logger(struct nf_logger *logger)
+{
+	int i;
+
+	spin_lock(&nf_log_lock);
+	for (i = 0; i < NPROTO; i++) {
+		if (nf_logging[i] == logger)
+			nf_logging[i] = NULL;
+	}
+	spin_unlock(&nf_log_lock);
+
+	synchronize_net();
+}
 
 void nf_log_packet(int pf,
 		   unsigned int hooknum,
 		   const struct sk_buff *skb,
 		   const struct net_device *in,
 		   const struct net_device *out,
+		   struct nf_loginfo *loginfo,
 		   const char *fmt, ...)
 {
 	va_list args;
 	char prefix[NF_LOG_PREFIXLEN];
-	nf_logfn *logfn;
+	struct nf_logger *logger;
 	
 	rcu_read_lock();
-	logfn = rcu_dereference(nf_logging[pf]);
-	if (logfn) {
+	logger = rcu_dereference(nf_logging[pf]);
+	if (logger) {
 		va_start(args, fmt);
 		vsnprintf(prefix, sizeof(prefix), fmt, args);
 		va_end(args);
 		/* We must read logging before nf_logfn[pf] */
-		logfn(hooknum, skb, in, out, prefix);
-	} else if (!reported) {
-		printk(KERN_WARNING "nf_log_packet: can\'t log yet, "
-		       "no backend logging module loaded in!\n");
-		reported++;
+		logger->logfn(pf, hooknum, skb, in, out, loginfo, prefix);
+	} else if (net_ratelimit()) {
+		printk(KERN_WARNING "nf_log_packet: can\'t log since "
+		       "no backend logging module loaded in! Please either "
+		       "load one, or disable logging explicitly\n");
 	}
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL(nf_log_register);
-EXPORT_SYMBOL(nf_log_unregister);
+EXPORT_SYMBOL(nf_log_unregister_pf);
+EXPORT_SYMBOL(nf_log_unregister_logger);
 EXPORT_SYMBOL(nf_log_packet);
+
+#ifdef CONFIG_PROC_FS
+struct proc_dir_entry *proc_net_netfilter;
+EXPORT_SYMBOL(proc_net_netfilter);
+
+static void *seq_start(struct seq_file *seq, loff_t *pos)
+{
+	rcu_read_lock();
+
+	if (*pos >= NPROTO)
+		return NULL;
+
+	return pos;
+}
+
+static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	(*pos)++;
+
+	if (*pos >= NPROTO)
+		return NULL;
+
+	return pos;
+}
+
+static void seq_stop(struct seq_file *s, void *v)
+{
+	rcu_read_unlock();
+}
+
+static int seq_show(struct seq_file *s, void *v)
+{
+	loff_t *pos = v;
+	const struct nf_logger *logger;
+
+	logger = rcu_dereference(nf_logging[*pos]);
+
+	if (!logger)
+		return seq_printf(s, "%2lld NONE\n", *pos);
+	
+	return seq_printf(s, "%2lld %s\n", *pos, logger->name);
+}
+
+static struct seq_operations nflog_seq_ops = {
+	.start	= seq_start,
+	.next	= seq_next,
+	.stop	= seq_stop,
+	.show	= seq_show,
+};
+
+static int nflog_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &nflog_seq_ops);
+}
+
+static struct file_operations nflog_file_ops = {
+	.owner	 = THIS_MODULE,
+	.open	 = nflog_open,
+	.read	 = seq_read,
+	.llseek	 = seq_lseek,
+	.release = seq_release,
+};
+
+#endif /* PROC_FS */
+
 
 /* This does not belong here, but locally generated errors need it if connection
    tracking in use: without this, connection may not be in hash table, and hence
···
 void __init netfilter_init(void)
 {
 	int i, h;
+#ifdef CONFIG_PROC_FS
+	struct proc_dir_entry *pde;
+#endif
 
 	queue_rerouter = kmalloc(NPROTO * sizeof(struct nf_queue_rerouter),
 				 GFP_KERNEL);
···
 		for (h = 0; h < NF_MAX_HOOKS; h++)
 			INIT_LIST_HEAD(&nf_hooks[i][h]);
 	}
+
+#ifdef CONFIG_PROC_FS
+	proc_net_netfilter = proc_mkdir("netfilter", proc_net);
+	if (!proc_net_netfilter)
+		panic("cannot create netfilter proc entry");
+	pde = create_proc_entry("nf_log", S_IRUGO, proc_net_netfilter);
+	if (!pde)
+		panic("cannot create /proc/net/netfilter/nf_log");
+	pde->proc_fops = &nflog_file_ops;
+#endif
 }
 
 EXPORT_SYMBOL(ip_ct_attach);

net/ipv4/netfilter/ip_conntrack_proto_icmp.c

···
 	icmph = skb_header_pointer(skb, skb->nh.iph->ihl*4, sizeof(_ih), &_ih);
 	if (icmph == NULL) {
 		if (LOG_INVALID(IPPROTO_ICMP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL,
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				      "ip_ct_icmp: short packet ");
 		return -NF_ACCEPT;
 	}
···
 		if (!(u16)csum_fold(skb->csum)) 
 			break;
 		if (LOG_INVALID(IPPROTO_ICMP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				      "ip_ct_icmp: bad HW ICMP checksum ");
 		return -NF_ACCEPT;
 	case CHECKSUM_NONE:
 		if ((u16)csum_fold(skb_checksum(skb, 0, skb->len, 0))) {
 			if (LOG_INVALID(IPPROTO_ICMP))
-				nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+				nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 					      "ip_ct_icmp: bad ICMP checksum ");
 			return -NF_ACCEPT;
 		}
···
 	 */
 	if (icmph->type > NR_ICMP_TYPES) {
 		if (LOG_INVALID(IPPROTO_ICMP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL,
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				      "ip_ct_icmp: invalid ICMP type ");
 		return -NF_ACCEPT;
 	}

net/ipv4/netfilter/ip_conntrack_proto_tcp.c

···
 		res = 1;
 	} else {
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL,
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 			"ip_ct_tcp: %s ",
 			before(seq, sender->td_maxend + 1) ?
 			after(end, sender->td_end - receiver->td_maxwin - 1) ?
···
 				sizeof(_tcph), &_tcph);
 	if (th == NULL) {
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				"ip_ct_tcp: short packet ");
 		return -NF_ACCEPT;
   	}
···
 	/* Not whole TCP header or malformed packet */
 	if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				"ip_ct_tcp: truncated/malformed packet ");
 		return -NF_ACCEPT;
 	}
···
 			         skb->ip_summed == CHECKSUM_HW ? skb->csum
 			      	 : skb_checksum(skb, iph->ihl*4, tcplen, 0))) {
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_tcp: bad TCP checksum ");
 		return -NF_ACCEPT;
 	}
···
 	tcpflags = (((u_int8_t *)th)[13] & ~(TH_ECE|TH_CWR));
 	if (!tcp_valid_flags[tcpflags]) {
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_tcp: invalid TCP flag combination ");
 		return -NF_ACCEPT;
 	}
···
 			 */
 		    	write_unlock_bh(&tcp_lock);
 			if (LOG_INVALID(IPPROTO_TCP))
-				nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
-					  "ip_ct_tcp: killing out of sync session ");
+				nf_log_packet(PF_INET, 0, skb, NULL, NULL,
+					      NULL, "ip_ct_tcp: "
+					      "killing out of sync session ");
 		    	if (del_timer(&conntrack->timeout))
 		    		conntrack->timeout.function((unsigned long)
 		    					    conntrack);
···
 		
 		write_unlock_bh(&tcp_lock);
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_tcp: invalid packet ignored ");
 		return NF_ACCEPT;
 	case TCP_CONNTRACK_MAX:
···
 		       old_state);
 		write_unlock_bh(&tcp_lock);
 		if (LOG_INVALID(IPPROTO_TCP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_tcp: invalid state ");
 		return -NF_ACCEPT;
 	case TCP_CONNTRACK_SYN_SENT:
···
 			write_unlock_bh(&tcp_lock);
 			if (LOG_INVALID(IPPROTO_TCP))
 				nf_log_packet(PF_INET, 0, skb, NULL, NULL,
-				              "ip_ct_tcp: invalid SYN");
+					      NULL, "ip_ct_tcp: invalid SYN");
 			return -NF_ACCEPT;
 		}
 	case TCP_CONNTRACK_CLOSE:

net/ipv4/netfilter/ip_conntrack_proto_udp.c

···
 	hdr = skb_header_pointer(skb, iph->ihl*4, sizeof(_hdr), &_hdr);
 	if (hdr == NULL) {
 		if (LOG_INVALID(IPPROTO_UDP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_udp: short packet ");
 		return -NF_ACCEPT;
 	}
···
 	/* Truncated/malformed packets */
 	if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
 		if (LOG_INVALID(IPPROTO_UDP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_udp: truncated/malformed packet ");
 		return -NF_ACCEPT;
 	}
···
 			         skb->ip_summed == CHECKSUM_HW ? skb->csum
 			      	 : skb_checksum(skb, iph->ihl*4, udplen, 0))) {
 		if (LOG_INVALID(IPPROTO_UDP))
-			nf_log_packet(PF_INET, 0, skb, NULL, NULL, 
+			nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
 				  "ip_ct_udp: bad UDP checksum ");
 		return -NF_ACCEPT;
 	}

net/ipv4/netfilter/ipt_LOG.c

···
 MODULE_AUTHOR("Netfilter Core Team <[e-mail]>");
 MODULE_DESCRIPTION("iptables syslog logging module");
 
-static unsigned int nflog = 1;
-module_param(nflog, int, 0400);
-MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
- 
 #if 0
 #define DEBUGP printk
 #else
···
 static DEFINE_SPINLOCK(log_lock);
 
 /* One level of recursion won't kill us */
-static void dump_packet(const struct ipt_log_info *info,
+static void dump_packet(const struct nf_loginfo *info,
 			const struct sk_buff *skb,
 			unsigned int iphoff)
 {
 	struct iphdr _iph, *ih;
+	unsigned int logflags;
+
+	if (info->type == NF_LOG_TYPE_LOG)
+		logflags = info->u.log.logflags;
+	else
+		logflags = NF_LOG_MASK;
 
 	ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
 	if (ih == NULL) {
···
 	if (ntohs(ih->frag_off) & IP_OFFSET)
 		printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
 
-	if ((info->logflags & IPT_LOG_IPOPT)
+	if ((logflags & IPT_LOG_IPOPT)
 	    && ih->ihl * 4 > sizeof(struct iphdr)) {
 		unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
 		unsigned int i, optsize;
···
 		printk("SPT=%u DPT=%u ",
 		       ntohs(th->source), ntohs(th->dest));
 		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
-		if (info->logflags & IPT_LOG_TCPSEQ)
+		if (logflags & IPT_LOG_TCPSEQ)
 			printk("SEQ=%u ACK=%u ",
 			       ntohl(th->seq), ntohl(th->ack_seq));
 		/* Max length: 13 "WINDOW=65535 " */
···
 		/* Max length: 11 "URGP=65535 " */
 		printk("URGP=%u ", ntohs(th->urg_ptr));
 
-		if ((info->logflags & IPT_LOG_TCPOPT)
+		if ((logflags & IPT_LOG_TCPOPT)
 		    && th->doff * 4 > sizeof(struct tcphdr)) {
 			unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
 			unsigned char *op;
···
 	}
 
 	/* Max length: 15 "UID=4294967295 " */
- 	if ((info->logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
+ 	if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
 		read_lock_bh(&skb->sk->sk_callback_lock);
 		if (skb->sk->sk_socket && skb->sk->sk_socket->file)
  			printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
···
 	/* maxlen = 230+   91  + 230 + 252 = 803 */
 }
 
+struct nf_loginfo default_loginfo = {
+	.type	= NF_LOG_TYPE_LOG,
+	.u = {
+		.log = {
+			.level    = 0,
+			.logflags = NF_LOG_MASK,
+		},
+	},
+};
+
 static void
-ipt_log_packet(unsigned int hooknum,
+ipt_log_packet(unsigned int pf,
+	       unsigned int hooknum,
 	       const struct sk_buff *skb,
 	       const struct net_device *in,
 	       const struct net_device *out,
-	       const struct ipt_log_info *loginfo,
-	       const char *level_string,
+	       const struct nf_loginfo *loginfo,
 	       const char *prefix)
 {
+	if (!loginfo)
+		loginfo = &default_loginfo;
+
 	spin_lock_bh(&log_lock);
-	printk(level_string);
-	printk("%sIN=%s OUT=%s ",
-	       prefix == NULL ? loginfo->prefix : prefix,
+	printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
+	       prefix,
 	       in ? in->name : "",
 	       out ? out->name : "");
 #ifdef CONFIG_BRIDGE_NETFILTER
···
 	       void *userinfo)
 {
 	const struct ipt_log_info *loginfo = targinfo;
-	char level_string[4] = "< >";
+	struct nf_loginfo li;
 
-	level_string[1] = '0' + (loginfo->level % 8);
-	ipt_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL);
+	li.type = NF_LOG_TYPE_LOG;
+	li.u.log.level = loginfo->level;
+	li.u.log.logflags = loginfo->logflags;
+
+	nf_log_packet(PF_INET, hooknum, *pskb, in, out, &li, loginfo->prefix);
 
 	return IPT_CONTINUE;
-}
-
-static void
-ipt_logfn(unsigned int hooknum,
-	  const struct sk_buff *skb,
-	  const struct net_device *in,
-	  const struct net_device *out,
-	  const char *prefix)
-{
-	struct ipt_log_info loginfo = { 
-		.level = 0, 
-		.logflags = IPT_LOG_MASK, 
-		.prefix = "" 
-	};
-
-	ipt_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix);
 }
 
 static int ipt_log_checkentry(const char *tablename,
···
 	.me		= THIS_MODULE,
 };
 
+static struct nf_logger ipt_log_logger ={
+	.name		= "ipt_LOG",
+	.logfn		= &ipt_log_packet,
+	.me		= THIS_MODULE,
+};
+
 static int __init init(void)
 {
 	if (ipt_register_target(&ipt_log_reg))
 		return -EINVAL;
-	if (nflog)
-		nf_log_register(PF_INET, &ipt_logfn);
+	if (nf_log_register(PF_INET, &ipt_log_logger) < 0) {
+		printk(KERN_WARNING "ipt_LOG: not logging via system console "
+		       "since somebody else already registered for PF_INET\n");
+		/* we cannot make module load fail here, since otherwise
+		 * iptables userspace would abort */
+	}
 	
 	return 0;
 }
 
 static void __exit fini(void)
 {
-	if (nflog)
-		nf_log_unregister(PF_INET, &ipt_logfn);
+	nf_log_unregister_logger(&ipt_log_logger);
 	ipt_unregister_target(&ipt_log_reg);
 }
 

net/ipv4/netfilter/ipt_ULOG.c

···
  	return IPT_CONTINUE;
 }
  
-static void ipt_logfn(unsigned int hooknum,
+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 = { 
-		.nl_group = ULOG_DEFAULT_NLGROUP,
-		.copy_range = 0,
-		.qthreshold = ULOG_DEFAULT_QTHRESHOLD,
-		.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);
 }
···
 	.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;
···
 		return -EINVAL;
 	}
 	if (nflog)
-		nf_log_register(PF_INET, &ipt_logfn);
+		nf_log_register(PF_INET, &ipt_ulog_logger);
 	
 	return 0;
 }
···
 	DEBUGP("ipt_ULOG: cleanup_module\n");
 
 	if (nflog)
-		nf_log_unregister(PF_INET, &ipt_logfn);
+		nf_log_unregister_logger(&ipt_ulog_logger);
 	ipt_unregister_target(&ipt_ulog_reg);
 	sock_release(nflognl->sk_socket);
 

net/ipv6/netfilter/ip6t_LOG.c

···
 MODULE_DESCRIPTION("IP6 tables LOG target module");
 MODULE_LICENSE("GPL");
 
-static unsigned int nflog = 1;
-module_param(nflog, int, 0400);
-MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
- 
 struct in_device;
 #include <net/route.h>
 #include <linux/netfilter_ipv6/ip6t_LOG.h>
···
 static DEFINE_SPINLOCK(log_lock);
 
 /* One level of recursion won't kill us */
-static void dump_packet(const struct ip6t_log_info *info,
+static void dump_packet(const struct nf_loginfo *info,
 			const struct sk_buff *skb, unsigned int ip6hoff,
 			int recurse)
 {
···
 	struct ipv6hdr _ip6h, *ih;
 	unsigned int ptr;
 	unsigned int hdrlen = 0;
+	unsigned int logflags;
+
+	if (info->type == NF_LOG_TYPE_LOG)
+		logflags = info->u.log.logflags;
+	else
+		logflags = NF_LOG_MASK;
 
 	ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
 	if (ih == NULL) {
···
 		}
 
 		/* Max length: 48 "OPT (...) " */
-		if (info->logflags & IP6T_LOG_IPOPT)
+		if (logflags & IP6T_LOG_IPOPT)
 			printk("OPT ( ");
 
 		switch (currenthdr) {
···
 		case IPPROTO_ROUTING:
 		case IPPROTO_HOPOPTS:
 			if (fragment) {
-				if (info->logflags & IP6T_LOG_IPOPT)
+				if (logflags & IP6T_LOG_IPOPT)
 					printk(")");
 				return;
 			}
···
 			break;
 		/* Max Length */
 		case IPPROTO_AH:
-			if (info->logflags & IP6T_LOG_IPOPT) {
+			if (logflags & IP6T_LOG_IPOPT) {
 				struct ip_auth_hdr _ahdr, *ah;
 
 				/* Max length: 3 "AH " */
···
 			hdrlen = (hp->hdrlen+2)<<2;
 			break;
 		case IPPROTO_ESP:
-			if (info->logflags & IP6T_LOG_IPOPT) {
+			if (logflags & IP6T_LOG_IPOPT) {
 				struct ip_esp_hdr _esph, *eh;
 
 				/* Max length: 4 "ESP " */
···
 			printk("Unknown Ext Hdr %u", currenthdr);
 			return;
 		}
-		if (info->logflags & IP6T_LOG_IPOPT)
+		if (logflags & IP6T_LOG_IPOPT)
 			printk(") ");
 
 		currenthdr = hp->nexthdr;
···
 		printk("SPT=%u DPT=%u ",
 		       ntohs(th->source), ntohs(th->dest));
 		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
-		if (info->logflags & IP6T_LOG_TCPSEQ)
+		if (logflags & IP6T_LOG_TCPSEQ)
 			printk("SEQ=%u ACK=%u ",
 			       ntohl(th->seq), ntohl(th->ack_seq));
 		/* Max length: 13 "WINDOW=65535 " */
···
 		/* Max length: 11 "URGP=65535 " */
 		printk("URGP=%u ", ntohs(th->urg_ptr));
 
-		if ((info->logflags & IP6T_LOG_TCPOPT)
+		if ((logflags & IP6T_LOG_TCPOPT)
 		    && th->doff * 4 > sizeof(struct tcphdr)) {
 			u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
 			unsigned int i;
···
 	}
 
 	/* Max length: 15 "UID=4294967295 " */
-	if ((info->logflags & IP6T_LOG_UID) && recurse && skb->sk) {
+	if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
 		read_lock_bh(&skb->sk->sk_callback_lock);
 		if (skb->sk->sk_socket && skb->sk->sk_socket->file)
 			printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
···
 	}
 }
 
+static struct nf_loginfo default_loginfo = {
+	.type	= NF_LOG_TYPE_LOG,
+	.u = {
+		.log = {
+			.level	  = 0,
+			.logflags = NF_LOG_MASK,
+		},
+	},
+};
+
 static void
-ip6t_log_packet(unsigned int hooknum,
+ip6t_log_packet(unsigned int pf,
+		unsigned int hooknum,
 		const struct sk_buff *skb,
 		const struct net_device *in,
 		const struct net_device *out,
-		const struct ip6t_log_info *loginfo,
-		const char *level_string,
+		const struct nf_loginfo *loginfo,
 		const char *prefix)
 {
+	if (!loginfo)
+		loginfo = &default_loginfo;
+
 	spin_lock_bh(&log_lock);
-	printk(level_string);
-	printk("%sIN=%s OUT=%s ",
-		prefix == NULL ? loginfo->prefix : prefix,
+	printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level, 
+		prefix,
 		in ? in->name : "",
 		out ? out->name : "");
 	if (in && !out) {
···
 		void *userinfo)
 {
 	const struct ip6t_log_info *loginfo = targinfo;
-	char level_string[4] = "< >";
+	struct nf_loginfo li;
 
-	level_string[1] = '0' + (loginfo->level % 8);
-	ip6t_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL);
+	li.type = NF_LOG_TYPE_LOG;
+	li.u.log.level = loginfo->level;
+	li.u.log.logflags = loginfo->logflags;
+
+	nf_log_packet(PF_INET6, hooknum, *pskb, in, out, &li, loginfo->prefix);
 
 	return IP6T_CONTINUE;
 }
 
-static void
-ip6t_logfn(unsigned int hooknum,
-	   const struct sk_buff *skb,
-	   const struct net_device *in,
-	   const struct net_device *out,
-	   const char *prefix)
-{
-	struct ip6t_log_info loginfo = {
-		.level = 0,
-		.logflags = IP6T_LOG_MASK,
-		.prefix = ""
-	};
-
-	ip6t_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix);
-}
 
 static int ip6t_log_checkentry(const char *tablename,
 			       const struct ip6t_entry *e,
···
 	.me 		= THIS_MODULE,
 };
 
+static struct nf_logger ip6t_logger = {
+	.name		= "ip6t_LOG",
+	.logfn		= &ip6t_log_packet,
+	.me		= THIS_MODULE,
+};
+
 static int __init init(void)
 {
 	if (ip6t_register_target(&ip6t_log_reg))
 		return -EINVAL;
-	if (nflog)
-		nf_log_register(PF_INET6, &ip6t_logfn);
+	if (nf_log_register(PF_INET6, &ip6t_logger) < 0) {
+		printk(KERN_WARNING "ip6t_LOG: not logging via system console "
+		       "since somebody else already registered for PF_INET6\n");
+		/* we cannot make module load fail here, since otherwise
+		 * ip6tables userspace would abort */
+	}
 
 	return 0;
 }
 
 static void __exit fini(void)
 {
-	if (nflog)
-		nf_log_unregister(PF_INET6, &ip6t_logfn);
+	nf_log_unregister_logger(&ip6t_logger);
 	ip6t_unregister_target(&ip6t_log_reg);
 }