// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ebt_log
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*
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* Authors:
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* Bart De Schuymer <bdschuym@pandora.be>
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* Harald Welte <laforge@netfilter.org>
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*
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* April, 2002
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*
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*/
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#include <linux/module.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/if_arp.h>
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#include <linux/spinlock.h>
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#include <net/netfilter/nf_log.h>
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#include <linux/in6.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_bridge/ebt_log.h>
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#include <linux/netfilter.h>
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static DEFINE_SPINLOCK(ebt_log_lock);
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static int ebt_log_tg_check(const struct xt_tgchk_param *par)
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{
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struct ebt_log_info *info = par->targinfo;
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if (info->bitmask & ~EBT_LOG_MASK)
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return -EINVAL;
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if (info->loglevel >= 8)
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return -EINVAL;
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info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
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return 0;
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}
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struct tcpudphdr {
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__be16 src;
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__be16 dst;
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};
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struct arppayload {
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unsigned char mac_src[ETH_ALEN];
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unsigned char ip_src[4];
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unsigned char mac_dst[ETH_ALEN];
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unsigned char ip_dst[4];
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};
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static void
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print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
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{
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if (protocol == IPPROTO_TCP ||
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protocol == IPPROTO_UDP ||
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protocol == IPPROTO_UDPLITE ||
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protocol == IPPROTO_SCTP ||
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protocol == IPPROTO_DCCP) {
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const struct tcpudphdr *pptr;
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struct tcpudphdr _ports;
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pptr = skb_header_pointer(skb, offset,
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sizeof(_ports), &_ports);
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if (pptr == NULL) {
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pr_cont(" INCOMPLETE TCP/UDP header");
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return;
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}
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pr_cont(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
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}
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}
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static void
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ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum,
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const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const struct nf_loginfo *loginfo,
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const char *prefix)
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{
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unsigned int bitmask;
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/* FIXME: Disabled from containers until syslog ns is supported */
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if (!net_eq(net, &init_net) && !sysctl_nf_log_all_netns)
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return;
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spin_lock_bh(&ebt_log_lock);
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printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
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'0' + loginfo->u.log.level, prefix,
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in ? in->name : "", out ? out->name : "",
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eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
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ntohs(eth_hdr(skb)->h_proto));
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if (loginfo->type == NF_LOG_TYPE_LOG)
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bitmask = loginfo->u.log.logflags;
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else
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bitmask = NF_LOG_DEFAULT_MASK;
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if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
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htons(ETH_P_IP)) {
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const struct iphdr *ih;
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struct iphdr _iph;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (ih == NULL) {
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pr_cont(" INCOMPLETE IP header");
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goto out;
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}
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pr_cont(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
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&ih->saddr, &ih->daddr, ih->tos, ih->protocol);
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print_ports(skb, ih->protocol, ih->ihl*4);
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goto out;
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}
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#if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
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if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
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htons(ETH_P_IPV6)) {
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const struct ipv6hdr *ih;
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struct ipv6hdr _iph;
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uint8_t nexthdr;
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__be16 frag_off;
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int offset_ph;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (ih == NULL) {
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pr_cont(" INCOMPLETE IPv6 header");
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goto out;
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}
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pr_cont(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
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&ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
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nexthdr = ih->nexthdr;
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offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
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if (offset_ph == -1)
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goto out;
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print_ports(skb, nexthdr, offset_ph);
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goto out;
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}
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#endif
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if ((bitmask & EBT_LOG_ARP) &&
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((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
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(eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
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const struct arphdr *ah;
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struct arphdr _arph;
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ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
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if (ah == NULL) {
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pr_cont(" INCOMPLETE ARP header");
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goto out;
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}
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pr_cont(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
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ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
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ntohs(ah->ar_op));
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/* If it's for Ethernet and the lengths are OK,
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* then log the ARP payload
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*/
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if (ah->ar_hrd == htons(1) &&
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ah->ar_hln == ETH_ALEN &&
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ah->ar_pln == sizeof(__be32)) {
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const struct arppayload *ap;
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struct arppayload _arpp;
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ap = skb_header_pointer(skb, sizeof(_arph),
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sizeof(_arpp), &_arpp);
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if (ap == NULL) {
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pr_cont(" INCOMPLETE ARP payload");
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goto out;
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}
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pr_cont(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
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ap->mac_src, ap->ip_src,
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ap->mac_dst, ap->ip_dst);
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}
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}
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out:
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pr_cont("\n");
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spin_unlock_bh(&ebt_log_lock);
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}
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static unsigned int
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ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct ebt_log_info *info = par->targinfo;
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struct nf_loginfo li;
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struct net *net = xt_net(par);
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li.type = NF_LOG_TYPE_LOG;
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li.u.log.level = info->loglevel;
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li.u.log.logflags = info->bitmask;
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/* Remember that we have to use ebt_log_packet() not to break backward
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* compatibility. We cannot use the default bridge packet logger via
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* nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
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*/
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if (info->bitmask & EBT_LOG_NFLOG)
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nf_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
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xt_in(par), xt_out(par), &li, "%s",
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info->prefix);
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else
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ebt_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
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xt_in(par), xt_out(par), &li, info->prefix);
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return EBT_CONTINUE;
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}
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static struct xt_target ebt_log_tg_reg __read_mostly = {
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.name = "log",
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.revision = 0,
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.family = NFPROTO_BRIDGE,
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.target = ebt_log_tg,
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.checkentry = ebt_log_tg_check,
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.targetsize = sizeof(struct ebt_log_info),
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.me = THIS_MODULE,
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};
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static int __init ebt_log_init(void)
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{
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return xt_register_target(&ebt_log_tg_reg);
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}
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static void __exit ebt_log_fini(void)
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{
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xt_unregister_target(&ebt_log_tg_reg);
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}
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module_init(ebt_log_init);
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module_exit(ebt_log_fini);
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MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
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MODULE_LICENSE("GPL");
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