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/*
* ebt_log
*
* Authors:
* Bart De Schuymer <bdschuym@pandora.be>
* Harald Welte <laforge@netfilter.org>
*
* April, 2002
*
*/
#include <linux/in.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_log.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/ip.h>
#include <linux/if_arp.h>
#include <linux/spinlock.h>
static DEFINE_SPINLOCK(ebt_log_lock);
static int ebt_log_check(const char *tablename, unsigned int hookmask,
const struct ebt_entry *e, void *data, unsigned int datalen)
{
struct ebt_log_info *info = (struct ebt_log_info *)data;
if (datalen != EBT_ALIGN(sizeof(struct ebt_log_info)))
return -EINVAL;
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
{
uint16_t src;
uint16_t 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_MAC(unsigned char *p)
{
int i;
for (i = 0; i < ETH_ALEN; i++, p++)
printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
}
#define myNIPQUAD(a) a[0], a[1], a[2], a[3]
static void
ebt_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 nf_loginfo *loginfo,
const char *prefix)
{
unsigned int bitmask;
spin_lock_bh(&ebt_log_lock);
printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
prefix, in ? in->name : "", out ? out->name : "");
print_MAC(eth_hdr(skb)->h_source);
printk("MAC dest = ");
print_MAC(eth_hdr(skb)->h_dest);
printk("proto = 0x%04x", 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)){
struct iphdr _iph, *ih;
ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
if (ih == NULL) {
printk(" INCOMPLETE IP header");
goto out;
}
printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
"tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
NIPQUAD(ih->daddr), ih->tos, ih->protocol);
if (ih->protocol == IPPROTO_TCP ||
ih->protocol == IPPROTO_UDP) {
struct tcpudphdr _ports, *pptr;
pptr = skb_header_pointer(skb, ih->ihl*4,
sizeof(_ports), &_ports);
if (pptr == NULL) {
printk(" INCOMPLETE TCP/UDP header");
goto out;
}
printk(" SPT=%u DPT=%u", ntohs(pptr->src),
ntohs(pptr->dst));
}
goto out;
}
if ((bitmask & EBT_LOG_ARP) &&
((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
(eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
struct arphdr _arph, *ah;
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(uint32_t)) {
struct arppayload _arpp, *ap;
ap = skb_header_pointer(skb, sizeof(_arph),
sizeof(_arpp), &_arpp);
if (ap == NULL) {
printk(" INCOMPLETE ARP payload");
goto out;
}
printk(" ARP MAC SRC=");
print_MAC(ap->mac_src);
printk(" ARP IP SRC=%u.%u.%u.%u",
myNIPQUAD(ap->ip_src));
printk(" ARP MAC DST=");
print_MAC(ap->mac_dst);
printk(" ARP IP DST=%u.%u.%u.%u",
myNIPQUAD(ap->ip_dst));
}
}
out:
printk("\n");
spin_unlock_bh(&ebt_log_lock);
}
static void ebt_log(const struct sk_buff *skb, unsigned int hooknr,
const struct net_device *in, const struct net_device *out,
const void *data, unsigned int datalen)
{
struct ebt_log_info *info = (struct ebt_log_info *)data;
struct nf_loginfo li;
li.type = NF_LOG_TYPE_LOG;
li.u.log.level = info->loglevel;
li.u.log.logflags = info->bitmask;
nf_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li, info->prefix);
}
static struct ebt_watcher log =
{
.name = EBT_LOG_WATCHER,
.watcher = ebt_log,
.check = ebt_log_check,
.me = THIS_MODULE,
};
static struct nf_logger ebt_log_logger = {
.name = "ebt_log",
.logfn = &ebt_log_packet,
.me = THIS_MODULE,
};
static int __init init(void)
{
int ret;
ret = ebt_register_watcher(&log);
if (ret < 0)
return ret;
if (nf_log_register(PF_BRIDGE, &ebt_log_logger) < 0) {
printk(KERN_WARNING "ebt_log: not logging via system console "
"since somebody else already registered for PF_INET\n");
/* we cannot make module load fail here, since otherwise
* ebtables userspace would abort */
}
return 0;
}
static void __exit fini(void)
{
nf_log_unregister_logger(&ebt_log_logger);
ebt_unregister_watcher(&log);
}
module_init(init);
module_exit(fini);
MODULE_LICENSE("GPL");
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