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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
  12 #include <linux/netfilter_bridge/ebtables.h>
  13 #include <linux/netfilter_bridge/ebt_log.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/module.h>
  16 #include <linux/ip.h>
  17 #include <linux/in.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/spinlock.h>
  20 #include <net/netfilter/nf_log.h>
  21
  22 static DEFINE_SPINLOCK(ebt_log_lock);
  23
  24 static int ebt_log_check(const char *tablename, unsigned int hookmask,
  25    const struct ebt_entry *e, void *data, unsigned int datalen)
  26 {
  27         struct ebt_log_info *info = data;
  28
  29         if (datalen != EBT_ALIGN(sizeof(struct ebt_log_info)))
  30                 return -EINVAL;
  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 print_MAC(const unsigned char *p)
  54 {
  55         int i;
  56
  57         for (i = 0; i < ETH_ALEN; i++, p++)
  58                 printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
  59 }
  60
  61 #define myNIPQUAD(a) a[0], a[1], a[2], a[3]
  62 static void
  63 ebt_log_packet(unsigned int pf, unsigned int hooknum,
  64    const struct sk_buff *skb, const struct net_device *in,
  65    const struct net_device *out, const struct nf_loginfo *loginfo,
  66    const char *prefix)
  67 {
  68         unsigned int bitmask;
  69
  70         spin_lock_bh(&ebt_log_lock);
  71         printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
  72                prefix, in ? in->name : "", out ? out->name : "");
  73
  74         print_MAC(eth_hdr(skb)->h_source);
  75         printk("MAC dest = ");
  76         print_MAC(eth_hdr(skb)->h_dest);
  77
  78         printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
  79
  80         if (loginfo->type == NF_LOG_TYPE_LOG)
  81                 bitmask = loginfo->u.log.logflags;
  82         else
  83                 bitmask = NF_LOG_MASK;
  84
  85         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  86            htons(ETH_P_IP)){
  87                 const struct iphdr *ih;
  88                 struct iphdr _iph;
  89
  90                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
  91                 if (ih == NULL) {
  92                         printk(" INCOMPLETE IP header");
  93                         goto out;
  94                 }
  95                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
  96                        "tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
  97                        NIPQUAD(ih->daddr), ih->tos, ih->protocol);
  98                 if (ih->protocol == IPPROTO_TCP ||
  99                     ih->protocol == IPPROTO_UDP ||
 100                     ih->protocol == IPPROTO_UDPLITE ||
 101                     ih->protocol == IPPROTO_SCTP ||
 102                     ih->protocol == IPPROTO_DCCP) {
 103                         const struct tcpudphdr *pptr;
 104                         struct tcpudphdr _ports;
 105
 106                         pptr = skb_header_pointer(skb, ih->ihl*4,
 107                                                   sizeof(_ports), &_ports);
 108                         if (pptr == NULL) {
 109                                 printk(" INCOMPLETE TCP/UDP header");
 110                                 goto out;
 111                         }
 112                         printk(" SPT=%u DPT=%u", ntohs(pptr->src),
 113                            ntohs(pptr->dst));
 114                 }
 115                 goto out;
 116         }
 117
 118         if ((bitmask & EBT_LOG_ARP) &&
 119             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 120              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 121                 const struct arphdr *ah;
 122                 struct arphdr _arph;
 123
 124                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 125                 if (ah == NULL) {
 126                         printk(" INCOMPLETE ARP header");
 127                         goto out;
 128                 }
 129                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 130                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 131                        ntohs(ah->ar_op));
 132
 133                 /* If it's for Ethernet and the lengths are OK,
 134                  * then log the ARP payload */
 135                 if (ah->ar_hrd == htons(1) &&
 136                     ah->ar_hln == ETH_ALEN &&
 137                     ah->ar_pln == sizeof(__be32)) {
 138                         const struct arppayload *ap;
 139                         struct arppayload _arpp;
 140
 141                         ap = skb_header_pointer(skb, sizeof(_arph),
 142                                                 sizeof(_arpp), &_arpp);
 143                         if (ap == NULL) {
 144                                 printk(" INCOMPLETE ARP payload");
 145                                 goto out;
 146                         }
 147                         printk(" ARP MAC SRC=");
 148                         print_MAC(ap->mac_src);
 149                         printk(" ARP IP SRC=%u.%u.%u.%u",
 150                                myNIPQUAD(ap->ip_src));
 151                         printk(" ARP MAC DST=");
 152                         print_MAC(ap->mac_dst);
 153                         printk(" ARP IP DST=%u.%u.%u.%u",
 154                                myNIPQUAD(ap->ip_dst));
 155                 }
 156         }
 157 out:
 158         printk("\n");
 159         spin_unlock_bh(&ebt_log_lock);
 160
 161 }
 162
 163 static void ebt_log(const struct sk_buff *skb, unsigned int hooknr,
 164    const struct net_device *in, const struct net_device *out,
 165    const void *data, unsigned int datalen)
 166 {
 167         const struct ebt_log_info *info = data;
 168         struct nf_loginfo li;
 169
 170         li.type = NF_LOG_TYPE_LOG;
 171         li.u.log.level = info->loglevel;
 172         li.u.log.logflags = info->bitmask;
 173
 174         if (info->bitmask & EBT_LOG_NFLOG)
 175                 nf_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
 176                               "%s", info->prefix);
 177         else
 178                 ebt_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
 179                                info->prefix);
 180 }
 181
 182 static struct ebt_watcher log =
 183 {
 184         .name           = EBT_LOG_WATCHER,
 185         .watcher        = ebt_log,
 186         .check          = ebt_log_check,
 187         .me             = THIS_MODULE,
 188 };
 189
 190 static const struct nf_logger ebt_log_logger = {
 191         .name           = "ebt_log",
 192         .logfn          = &ebt_log_packet,
 193         .me             = THIS_MODULE,
 194 };
 195
 196 static int __init ebt_log_init(void)
 197 {
 198         int ret;
 199
 200         ret = ebt_register_watcher(&log);
 201         if (ret < 0)
 202                 return ret;
 203         nf_log_register(PF_BRIDGE, &ebt_log_logger);
 204         return 0;
 205 }
 206
 207 static void __exit ebt_log_fini(void)
 208 {
 209         nf_log_unregister(&ebt_log_logger);
 210         ebt_unregister_watcher(&log);
 211 }
 212
 213 module_init(ebt_log_init);
 214 module_exit(ebt_log_fini);
 215 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 216 MODULE_LICENSE("GPL");