[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 <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 90 insertions, 64 deletions

diff --git a/net/ipv4/netfilter/ip_conntrack_proto_icmp.c b/net/ipv4/netfilter/ip_conntrack_proto_icmp.c
index 3f90cb9979ac..838d1d69b36e 100644
--- a/net/ipv4/netfilter/ip_conntrack_proto_icmp.c
+++ b/net/ipv4/netfilter/ip_conntrack_proto_icmp.c
@@ -217,7 +217,7 @@ icmp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 	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;
 	}
@@ -231,13 +231,13 @@ icmp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 		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;
 		}
@@ -254,7 +254,7 @@ checksum_skipped:
 	 */
 	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;
 	}
diff --git a/net/ipv4/netfilter/ip_conntrack_proto_tcp.c b/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
index c2bce22d4031..f23ef1f88c46 100644
--- a/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
+++ b/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
@@ -716,7 +716,7 @@ static int tcp_in_window(struct ip_ct_tcp *state,
 		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) ?
@@ -815,7 +815,7 @@ static int tcp_error(struct sk_buff *skb,
 				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;
   	}
@@ -823,7 +823,7 @@ static int tcp_error(struct sk_buff *skb,
 	/* 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;
 	}
@@ -840,7 +840,7 @@ static int tcp_error(struct sk_buff *skb,
 			         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;
 	}
@@ -849,7 +849,7 @@ static int tcp_error(struct sk_buff *skb,
 	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;
 	}
@@ -897,8 +897,9 @@ static int tcp_packet(struct ip_conntrack *conntrack,
 			 */
 		    	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);
@@ -912,7 +913,7 @@ static int tcp_packet(struct ip_conntrack *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:
@@ -922,7 +923,7 @@ static int tcp_packet(struct ip_conntrack *conntrack,
 		       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:
@@ -943,7 +944,7 @@ static int tcp_packet(struct ip_conntrack *conntrack,
 			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:
diff --git a/net/ipv4/netfilter/ip_conntrack_proto_udp.c b/net/ipv4/netfilter/ip_conntrack_proto_udp.c
index 14130169cbfd..f2dcac7c7660 100644
--- a/net/ipv4/netfilter/ip_conntrack_proto_udp.c
+++ b/net/ipv4/netfilter/ip_conntrack_proto_udp.c
@@ -98,7 +98,7 @@ static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 	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;
 	}
@@ -106,7 +106,7 @@ static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 	/* 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;
 	}
@@ -126,7 +126,7 @@ static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 			         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;
 	}
diff --git a/net/ipv4/netfilter/ipt_LOG.c b/net/ipv4/netfilter/ipt_LOG.c
index ef08733d26da..92ed050fac69 100644
--- a/net/ipv4/netfilter/ipt_LOG.c
+++ b/net/ipv4/netfilter/ipt_LOG.c
@@ -27,10 +27,6 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 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
@@ -41,11 +37,17 @@ MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
 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) {
@@ -76,7 +78,7 @@ static void dump_packet(const struct ipt_log_info *info,
 	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;
@@ -119,7 +121,7 @@ static void dump_packet(const struct ipt_log_info *info,
 		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 " */
@@ -146,7 +148,7 @@ static void dump_packet(const struct ipt_log_info *info,
 		/* 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;
@@ -328,7 +330,7 @@ static void dump_packet(const struct ipt_log_info *info,
 	}
 
 	/* 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);
@@ -349,19 +351,31 @@ static void dump_packet(const struct ipt_log_info *info,
 	/* 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
@@ -405,28 +419,15 @@ ipt_log_target(struct sk_buff **pskb,
 	       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;
 
-	return IPT_CONTINUE;
-}
+	nf_log_packet(PF_INET, hooknum, *pskb, in, out, &li, loginfo->prefix);
 
-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);
+	return IPT_CONTINUE;
 }
 
 static int ipt_log_checkentry(const char *tablename,
@@ -464,20 +465,29 @@ static struct ipt_target ipt_log_reg = {
 	.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);
 }
 
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index 4ea8371ab270..b86f06ec9762 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -304,18 +304,27 @@ static unsigned int ipt_ulog_target(struct sk_buff **pskb,
  	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);
 }
@@ -355,6 +364,12 @@ static struct ipt_target ipt_ulog_reg = {
 	.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;
@@ -382,7 +397,7 @@ static int __init init(void)
 		return -EINVAL;
 	}
 	if (nflog)
-		nf_log_register(PF_INET, &ipt_logfn);
+		nf_log_register(PF_INET, &ipt_ulog_logger);
 	
 	return 0;
 }
@@ -395,7 +410,7 @@ static void __exit fini(void)
 	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);