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   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 bool
  28 ebt_log_tg_check(const char *table, const void *entry,
  29                  const struct xt_target *target, void *data,
  30                  unsigned int hook_mask)
  31 {
  32         struct ebt_log_info *info = data;
  33
  34         if (info->bitmask & ~EBT_LOG_MASK)
  35                 return false;
  36         if (info->loglevel >= 8)
  37                 return false;
  38         info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
  39         return true;
  40 }
  41
  42 struct tcpudphdr
  43 {
  44         __be16 src;
  45         __be16 dst;
  46 };
  47
  48 struct arppayload
  49 {
  50         unsigned char mac_src[ETH_ALEN];
  51         unsigned char ip_src[4];
  52         unsigned char mac_dst[ETH_ALEN];
  53         unsigned char ip_dst[4];
  54 };
  55
  56 static void print_MAC(const unsigned char *p)
  57 {
  58         int i;
  59
  60         for (i = 0; i < ETH_ALEN; i++, p++)
  61                 printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
  62 }
  63
  64 static void
  65 print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
  66 {
  67         if (protocol == IPPROTO_TCP ||
  68             protocol == IPPROTO_UDP ||
  69             protocol == IPPROTO_UDPLITE ||
  70             protocol == IPPROTO_SCTP ||
  71             protocol == IPPROTO_DCCP) {
  72                 const struct tcpudphdr *pptr;
  73                 struct tcpudphdr _ports;
  74
  75                 pptr = skb_header_pointer(skb, offset,
  76                                           sizeof(_ports), &_ports);
  77                 if (pptr == NULL) {
  78                         printk(" INCOMPLETE TCP/UDP header");
  79                         return;
  80                 }
  81                 printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
  82         }
  83 }
  84
  85 #define myNIPQUAD(a) a[0], a[1], a[2], a[3]
  86 static void
  87 ebt_log_packet(u_int8_t pf, unsigned int hooknum,
  88    const struct sk_buff *skb, const struct net_device *in,
  89    const struct net_device *out, const struct nf_loginfo *loginfo,
  90    const char *prefix)
  91 {
  92         unsigned int bitmask;
  93
  94         spin_lock_bh(&ebt_log_lock);
  95         printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
  96                prefix, in ? in->name : "", out ? out->name : "");
  97
  98         print_MAC(eth_hdr(skb)->h_source);
  99         printk("MAC dest = ");
 100         print_MAC(eth_hdr(skb)->h_dest);
 101
 102         printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
 103
 104         if (loginfo->type == NF_LOG_TYPE_LOG)
 105                 bitmask = loginfo->u.log.logflags;
 106         else
 107                 bitmask = NF_LOG_MASK;
 108
 109         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
 110            htons(ETH_P_IP)){
 111                 const struct iphdr *ih;
 112                 struct iphdr _iph;
 113
 114                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 115                 if (ih == NULL) {
 116                         printk(" INCOMPLETE IP header");
 117                         goto out;
 118                 }
 119                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
 120                        "tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
 121                        NIPQUAD(ih->daddr), ih->tos, ih->protocol);
 122                 print_ports(skb, ih->protocol, ih->ihl*4);
 123                 goto out;
 124         }
 125
 126 #if defined(CONFIG_BRIDGE_EBT_IP6) || defined(CONFIG_BRIDGE_EBT_IP6_MODULE)
 127         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 128            htons(ETH_P_IPV6)) {
 129                 const struct ipv6hdr *ih;
 130                 struct ipv6hdr _iph;
 131                 uint8_t nexthdr;
 132                 int offset_ph;
 133
 134                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 135                 if (ih == NULL) {
 136                         printk(" INCOMPLETE IPv6 header");
 137                         goto out;
 138                 }
 139                 printk(" IPv6 SRC=%x:%x:%x:%x:%x:%x:%x:%x "
 140                        "IPv6 DST=%x:%x:%x:%x:%x:%x:%x:%x, IPv6 "
 141                        "priority=0x%01X, Next Header=%d", NIP6(ih->saddr),
 142                        NIP6(ih->daddr), ih->priority, ih->nexthdr);
 143                 nexthdr = ih->nexthdr;
 144                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr);
 145                 if (offset_ph == -1)
 146                         goto out;
 147                 print_ports(skb, nexthdr, offset_ph);
 148                 goto out;
 149         }
 150 #endif
 151
 152         if ((bitmask & EBT_LOG_ARP) &&
 153             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 154              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 155                 const struct arphdr *ah;
 156                 struct arphdr _arph;
 157
 158                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 159                 if (ah == NULL) {
 160                         printk(" INCOMPLETE ARP header");
 161                         goto out;
 162                 }
 163                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 164                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 165                        ntohs(ah->ar_op));
 166
 167                 /* If it's for Ethernet and the lengths are OK,
 168                  * then log the ARP payload */
 169                 if (ah->ar_hrd == htons(1) &&
 170                     ah->ar_hln == ETH_ALEN &&
 171                     ah->ar_pln == sizeof(__be32)) {
 172                         const struct arppayload *ap;
 173                         struct arppayload _arpp;
 174
 175                         ap = skb_header_pointer(skb, sizeof(_arph),
 176                                                 sizeof(_arpp), &_arpp);
 177                         if (ap == NULL) {
 178                                 printk(" INCOMPLETE ARP payload");
 179                                 goto out;
 180                         }
 181                         printk(" ARP MAC SRC=");
 182                         print_MAC(ap->mac_src);
 183                         printk(" ARP IP SRC=%u.%u.%u.%u",
 184                                myNIPQUAD(ap->ip_src));
 185                         printk(" ARP MAC DST=");
 186                         print_MAC(ap->mac_dst);
 187                         printk(" ARP IP DST=%u.%u.%u.%u",
 188                                myNIPQUAD(ap->ip_dst));
 189                 }
 190         }
 191 out:
 192         printk("\n");
 193         spin_unlock_bh(&ebt_log_lock);
 194
 195 }
 196
 197 static unsigned int
 198 ebt_log_tg(struct sk_buff *skb, const struct net_device *in,
 199            const struct net_device *out, unsigned int hooknr,
 200            const struct xt_target *target, const void *data)
 201 {
 202         const struct ebt_log_info *info = data;
 203         struct nf_loginfo li;
 204
 205         li.type = NF_LOG_TYPE_LOG;
 206         li.u.log.level = info->loglevel;
 207         li.u.log.logflags = info->bitmask;
 208
 209         if (info->bitmask & EBT_LOG_NFLOG)
 210                 nf_log_packet(NFPROTO_BRIDGE, hooknr, skb, in, out, &li,
 211                               "%s", info->prefix);
 212         else
 213                 ebt_log_packet(NFPROTO_BRIDGE, hooknr, skb, in, out, &li,
 214                                info->prefix);
 215         return EBT_CONTINUE;
 216 }
 217
 218 static struct xt_target ebt_log_tg_reg __read_mostly = {
 219         .name           = "log",
 220         .revision       = 0,
 221         .family         = NFPROTO_BRIDGE,
 222         .target         = ebt_log_tg,
 223         .checkentry     = ebt_log_tg_check,
 224         .targetsize     = XT_ALIGN(sizeof(struct ebt_log_info)),
 225         .me             = THIS_MODULE,
 226 };
 227
 228 static const struct nf_logger ebt_log_logger = {
 229         .name           = "ebt_log",
 230         .logfn          = &ebt_log_packet,
 231         .me             = THIS_MODULE,
 232 };
 233
 234 static int __init ebt_log_init(void)
 235 {
 236         int ret;
 237
 238         ret = xt_register_target(&ebt_log_tg_reg);
 239         if (ret < 0)
 240                 return ret;
 241         nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
 242         return 0;
 243 }
 244
 245 static void __exit ebt_log_fini(void)
 246 {
 247         nf_log_unregister(&ebt_log_logger);
 248         xt_unregister_target(&ebt_log_tg_reg);
 249 }
 250
 251 module_init(ebt_log_init);
 252 module_exit(ebt_log_fini);
 253 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 254 MODULE_LICENSE("GPL");