// SPDX-License-Identifier: GPL-2.0-only
/*
* ebt_log
*
* Authors:
* Bart De Schuymer <[email protected]>
* Harald Welte <[email protected]>
*
* 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) {
pr_cont(" INCOMPLETE TCP/UDP header");
return;
}
pr_cont(" 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) && !sysctl_nf_log_all_netns)
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_DEFAULT_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) {
pr_cont(" INCOMPLETE IP header");
goto out;
}
pr_cont(" 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) {
pr_cont(" INCOMPLETE IPv6 header");
goto out;
}
pr_cont(" 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) {
pr_cont(" INCOMPLETE ARP header");
goto out;
}
pr_cont(" 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) {
pr_cont(" INCOMPLETE ARP payload");
goto out;
}
pr_cont(" 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:
pr_cont("\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 = xt_net(par);
li.type = NF_LOG_TYPE_LOG;
li.u.log.level = info->loglevel;
li.u.log.logflags = info->bitmask;
/* Remember that we have to use ebt_log_packet() not to break backward
* compatibility. We cannot use the default bridge packet logger via
* nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
*/
if (info->bitmask & EBT_LOG_NFLOG)
nf_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
xt_in(par), xt_out(par), &li, "%s",
info->prefix);
else
ebt_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
xt_in(par), xt_out(par), &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 int __init ebt_log_init(void)
{
return xt_register_target(&ebt_log_tg_reg);
}
static void __exit ebt_log_fini(void)
{
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");
Codebase Browser
linux