text: /*
   *  ebt_log
   *
   *	Authors:
   *	Bart De Schuymer <bdschuym@pandora.be>
   *	Harald Welte <laforge@netfilter.org>
   *
   *  April, 2002
   *
   */
  #include <linux/module.h>
  #include <linux/ip.h>
  #include <linux/in.h>
  #include <linux/if_arp.h>
  #include <linux/spinlock.h>
  #include <net/netfilter/nf_log.h>
  #include <linux/ipv6.h>
  #include <net/ipv6.h>
  #include <linux/in6.h>
  #include <linux/netfilter/x_tables.h>
  #include <linux/netfilter_bridge/ebtables.h>
  #include <linux/netfilter_bridge/ebt_log.h>
  #include <linux/netfilter.h>
  
  static DEFINE_SPINLOCK(ebt_log_lock);
  
  static int ebt_log_tg_check(const struct xt_tgchk_param *par)
  {
  	struct ebt_log_info *info = par->targinfo;
  
  	if (info->bitmask & ~EBT_LOG_MASK)
  		return -EINVAL;
  	if (info->loglevel >= 8)
  		return -EINVAL;
  	info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
  	return 0;
  }
  
  struct tcpudphdr
  {
  	__be16 src;
  	__be16 dst;
  };
  
  struct arppayload
  {
  	unsigned char mac_src[ETH_ALEN];
  	unsigned char ip_src[4];
  	unsigned char mac_dst[ETH_ALEN];
  	unsigned char ip_dst[4];
  };
  
  static void
  print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
  {
  	if (protocol == IPPROTO_TCP ||
  	    protocol == IPPROTO_UDP ||
  	    protocol == IPPROTO_UDPLITE ||
  	    protocol == IPPROTO_SCTP ||
  	    protocol == IPPROTO_DCCP) {
  		const struct tcpudphdr *pptr;
  		struct tcpudphdr _ports;
  
  		pptr = skb_header_pointer(skb, offset,
  					  sizeof(_ports), &_ports);
  		if (pptr == NULL) {
  			printk(" INCOMPLETE TCP/UDP header");
  			return;
  		}
  		printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
  	}
  }
  
  static void
  ebt_log_packet(struct net *net, 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 *loginfo,
  	       const char *prefix)
  {
  	unsigned int bitmask;
  
  	/* FIXME: Disabled from containers until syslog ns is supported */
  	if (!net_eq(net, &init_net))
  		return;
  
  	spin_lock_bh(&ebt_log_lock);
  	printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
  	       '0' + loginfo->u.log.level, prefix,
  	       in ? in->name : "", out ? out->name : "",
  	       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
  	       ntohs(eth_hdr(skb)->h_proto));
  
  	if (loginfo->type == NF_LOG_TYPE_LOG)
  		bitmask = loginfo->u.log.logflags;
  	else
  		bitmask = NF_LOG_MASK;
  
  	if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  	   htons(ETH_P_IP)){
  		const struct iphdr *ih;
  		struct iphdr _iph;
  
  		ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
  		if (ih == NULL) {
  			printk(" INCOMPLETE IP header");
  			goto out;
  		}
  		printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
  		       &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
  		print_ports(skb, ih->protocol, ih->ihl*4);
  		goto out;
  	}
  
  #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
  	if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
  	   htons(ETH_P_IPV6)) {
  		const struct ipv6hdr *ih;
  		struct ipv6hdr _iph;
  		uint8_t nexthdr;
  		__be16 frag_off;
  		int offset_ph;
  
  		ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
  		if (ih == NULL) {
  			printk(" INCOMPLETE IPv6 header");
  			goto out;
  		}
  		printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
  		       &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
  		nexthdr = ih->nexthdr;
  		offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
  		if (offset_ph == -1)
  			goto out;
  		print_ports(skb, nexthdr, offset_ph);
  		goto out;
  	}
  #endif
  
  	if ((bitmask & EBT_LOG_ARP) &&
  	    ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
  	     (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
  		const struct arphdr *ah;
  		struct arphdr _arph;
  
  		ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
  		if (ah == NULL) {
  			printk(" INCOMPLETE ARP header");
  			goto out;
  		}
  		printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
  		       ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
  		       ntohs(ah->ar_op));
  
  		/* If it's for Ethernet and the lengths are OK,
  		 * then log the ARP payload */
  		if (ah->ar_hrd == htons(1) &&
  		    ah->ar_hln == ETH_ALEN &&
  		    ah->ar_pln == sizeof(__be32)) {
  			const struct arppayload *ap;
  			struct arppayload _arpp;
  
  			ap = skb_header_pointer(skb, sizeof(_arph),
  						sizeof(_arpp), &_arpp);
  			if (ap == NULL) {
  				printk(" INCOMPLETE ARP payload");
  				goto out;
  			}
  			printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
  					ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
  		}
  	}
  out:
  	printk("\n");
  	spin_unlock_bh(&ebt_log_lock);
  
  }
  
  static unsigned int
  ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
  {
  	const struct ebt_log_info *info = par->targinfo;
  	struct nf_loginfo li;
  	struct net *net = dev_net(par->in ? par->in : par->out);
  
  	li.type = NF_LOG_TYPE_LOG;
  	li.u.log.level = info->loglevel;
  	li.u.log.logflags = info->bitmask;
  
  	if (info->bitmask & EBT_LOG_NFLOG)
  		nf_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb,
  			      par->in, par->out, &li, "%s", info->prefix);
  	else
  		ebt_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb, par->in,
  			       par->out, &li, info->prefix);
  	return EBT_CONTINUE;
  }
  
  static struct xt_target ebt_log_tg_reg __read_mostly = {
  	.name		= "log",
  	.revision	= 0,
  	.family		= NFPROTO_BRIDGE,
  	.target		= ebt_log_tg,
  	.checkentry	= ebt_log_tg_check,
  	.targetsize	= sizeof(struct ebt_log_info),
  	.me		= THIS_MODULE,
  };
  
  static struct nf_logger ebt_log_logger __read_mostly = {
  	.name 		= "ebt_log",
  	.logfn		= &ebt_log_packet,
  	.me		= THIS_MODULE,
  };
  
  static int __net_init ebt_log_net_init(struct net *net)
  {
  	nf_log_set(net, NFPROTO_BRIDGE, &ebt_log_logger);
  	return 0;
  }
  
  static void __net_exit ebt_log_net_fini(struct net *net)
  {
  	nf_log_unset(net, &ebt_log_logger);
  }
  
  static struct pernet_operations ebt_log_net_ops = {
  	.init = ebt_log_net_init,
  	.exit = ebt_log_net_fini,
  };
  
  static int __init ebt_log_init(void)
  {
  	int ret;
  
  	ret = register_pernet_subsys(&ebt_log_net_ops);
  	if (ret < 0)
  		goto err_pernet;
  
  	ret = xt_register_target(&ebt_log_tg_reg);
  	if (ret < 0)
  		goto err_target;
  
  	nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
  
  	return ret;
  
  err_target:
  	unregister_pernet_subsys(&ebt_log_net_ops);
  err_pernet:
  	return ret;
  }
  
  static void __exit ebt_log_fini(void)
  {
  	unregister_pernet_subsys(&ebt_log_net_ops);
  	nf_log_unregister(&ebt_log_logger);
  	xt_unregister_target(&ebt_log_tg_reg);
  }
  
  module_init(ebt_log_init);
  module_exit(ebt_log_fini);
  MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
  MODULE_LICENSE("GPL");
  