1 /* 2 * ebt_log 3 * 4 * Authors: 5 * Bart De Schuymer <bdschuym@pandora.be> 6 * Harald Welte <laforge@netfilter.org> 7 * 8 * April, 2002 9 * 10 */ 11 #include <linux/module.h> 12 #include <linux/ip.h> 13 #include <linux/in.h> 14 #include <linux/if_arp.h> 15 #include <linux/spinlock.h> 16 #include <net/netfilter/nf_log.h> 17 #include <linux/ipv6.h> 18 #include <net/ipv6.h> 19 #include <linux/in6.h> 20 #include <linux/netfilter/x_tables.h> 21 #include <linux/netfilter_bridge/ebtables.h> 22 #include <linux/netfilter_bridge/ebt_log.h> 23 #include <linux/netfilter.h> 24 25 static DEFINE_SPINLOCK(ebt_log_lock); 26 27 static int ebt_log_tg_check(const struct xt_tgchk_param *par) 28 { 29 struct ebt_log_info *info = par->targinfo; 30 31 if (info->bitmask & ~EBT_LOG_MASK) 32 return -EINVAL; 33 if (info->loglevel >= 8) 34 return -EINVAL; 35 info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0'; 36 return 0; 37 } 38 39 struct tcpudphdr 40 { 41 __be16 src; 42 __be16 dst; 43 }; 44 45 struct arppayload 46 { 47 unsigned char mac_src[ETH_ALEN]; 48 unsigned char ip_src[4]; 49 unsigned char mac_dst[ETH_ALEN]; 50 unsigned char ip_dst[4]; 51 }; 52 53 static void 54 print_ports(const struct sk_buff *skb, uint8_t protocol, int offset) 55 { 56 if (protocol == IPPROTO_TCP || 57 protocol == IPPROTO_UDP || 58 protocol == IPPROTO_UDPLITE || 59 protocol == IPPROTO_SCTP || 60 protocol == IPPROTO_DCCP) { 61 const struct tcpudphdr *pptr; 62 struct tcpudphdr _ports; 63 64 pptr = skb_header_pointer(skb, offset, 65 sizeof(_ports), &_ports); 66 if (pptr == NULL) { 67 printk(" INCOMPLETE TCP/UDP header"); 68 return; 69 } 70 printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst)); 71 } 72 } 73 74 static void 75 ebt_log_packet(u_int8_t pf, unsigned int hooknum, 76 const struct sk_buff *skb, const struct net_device *in, 77 const struct net_device *out, const struct nf_loginfo *loginfo, 78 const char *prefix) 79 { 80 unsigned int bitmask; 81 82 spin_lock_bh(&ebt_log_lock); 83 printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x", 84 '0' + loginfo->u.log.level, prefix, 85 in ? in->name : "", out ? out->name : "", 86 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, 87 ntohs(eth_hdr(skb)->h_proto)); 88 89 if (loginfo->type == NF_LOG_TYPE_LOG) 90 bitmask = loginfo->u.log.logflags; 91 else 92 bitmask = NF_LOG_MASK; 93 94 if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto == 95 htons(ETH_P_IP)){ 96 const struct iphdr *ih; 97 struct iphdr _iph; 98 99 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); 100 if (ih == NULL) { 101 printk(" INCOMPLETE IP header"); 102 goto out; 103 } 104 printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d", 105 &ih->saddr, &ih->daddr, ih->tos, ih->protocol); 106 print_ports(skb, ih->protocol, ih->ihl*4); 107 goto out; 108 } 109 110 #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6) 111 if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto == 112 htons(ETH_P_IPV6)) { 113 const struct ipv6hdr *ih; 114 struct ipv6hdr _iph; 115 uint8_t nexthdr; 116 __be16 frag_off; 117 int offset_ph; 118 119 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); 120 if (ih == NULL) { 121 printk(" INCOMPLETE IPv6 header"); 122 goto out; 123 } 124 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d", 125 &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr); 126 nexthdr = ih->nexthdr; 127 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off); 128 if (offset_ph == -1) 129 goto out; 130 print_ports(skb, nexthdr, offset_ph); 131 goto out; 132 } 133 #endif 134 135 if ((bitmask & EBT_LOG_ARP) && 136 ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) || 137 (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) { 138 const struct arphdr *ah; 139 struct arphdr _arph; 140 141 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph); 142 if (ah == NULL) { 143 printk(" INCOMPLETE ARP header"); 144 goto out; 145 } 146 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d", 147 ntohs(ah->ar_hrd), ntohs(ah->ar_pro), 148 ntohs(ah->ar_op)); 149 150 /* If it's for Ethernet and the lengths are OK, 151 * then log the ARP payload */ 152 if (ah->ar_hrd == htons(1) && 153 ah->ar_hln == ETH_ALEN && 154 ah->ar_pln == sizeof(__be32)) { 155 const struct arppayload *ap; 156 struct arppayload _arpp; 157 158 ap = skb_header_pointer(skb, sizeof(_arph), 159 sizeof(_arpp), &_arpp); 160 if (ap == NULL) { 161 printk(" INCOMPLETE ARP payload"); 162 goto out; 163 } 164 printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4", 165 ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst); 166 } 167 } 168 out: 169 printk("\n"); 170 spin_unlock_bh(&ebt_log_lock); 171 172 } 173 174 static unsigned int 175 ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par) 176 { 177 const struct ebt_log_info *info = par->targinfo; 178 struct nf_loginfo li; 179 180 li.type = NF_LOG_TYPE_LOG; 181 li.u.log.level = info->loglevel; 182 li.u.log.logflags = info->bitmask; 183 184 if (info->bitmask & EBT_LOG_NFLOG) 185 nf_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in, 186 par->out, &li, "%s", info->prefix); 187 else 188 ebt_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in, 189 par->out, &li, info->prefix); 190 return EBT_CONTINUE; 191 } 192 193 static struct xt_target ebt_log_tg_reg __read_mostly = { 194 .name = "log", 195 .revision = 0, 196 .family = NFPROTO_BRIDGE, 197 .target = ebt_log_tg, 198 .checkentry = ebt_log_tg_check, 199 .targetsize = sizeof(struct ebt_log_info), 200 .me = THIS_MODULE, 201 }; 202 203 static struct nf_logger ebt_log_logger __read_mostly = { 204 .name = "ebt_log", 205 .logfn = &ebt_log_packet, 206 .me = THIS_MODULE, 207 }; 208 209 static int __init ebt_log_init(void) 210 { 211 int ret; 212 213 ret = xt_register_target(&ebt_log_tg_reg); 214 if (ret < 0) 215 return ret; 216 nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger); 217 return 0; 218 } 219 220 static void __exit ebt_log_fini(void) 221 { 222 nf_log_unregister(&ebt_log_logger); 223 xt_unregister_target(&ebt_log_tg_reg); 224 } 225 226 module_init(ebt_log_init); 227 module_exit(ebt_log_fini); 228 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog"); 229 MODULE_LICENSE("GPL"); 230