/* * 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(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; spin_lock_bh(&ebt_log_lock); printk("<%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; 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(NFPROTO_BRIDGE, par->hooknum, skb, par->in, par->out, &li, "%s", info->prefix); else ebt_log_packet(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 __init ebt_log_init(void) { int ret; ret = xt_register_target(&ebt_log_tg_reg); if (ret < 0) return ret; nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger); return 0; } static void __exit ebt_log_fini(void) { 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");