net/bridge/netfilter/ebt_log.c

   1 /*
   2  *  ebt_log
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10
  11 #include <linux/netfilter_bridge/ebtables.h>
  12 #include <linux/netfilter_bridge/ebt_log.h>
  13 #include <linux/module.h>
  14 #include <linux/ip.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/spinlock.h>
  17
  18 static spinlock_t ebt_log_lock = SPIN_LOCK_UNLOCKED;
  19
  20 static int ebt_log_check(const char *tablename, unsigned int hookmask,
  21    const struct ebt_entry *e, void *data, unsigned int datalen)
  22 {
  23         struct ebt_log_info *info = (struct ebt_log_info *)data;
  24
  25         if (datalen != EBT_ALIGN(sizeof(struct ebt_log_info)))
  26                 return -EINVAL;
  27         if (info->bitmask & ~EBT_LOG_MASK)
  28                 return -EINVAL;
  29         if (info->loglevel >= 8)
  30                 return -EINVAL;
  31         info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
  32         return 0;
  33 }
  34
  35 struct tcpudphdr
  36 {
  37         uint16_t src;
  38         uint16_t dst;
  39 };
  40
  41 struct arppayload
  42 {
  43         unsigned char mac_src[ETH_ALEN];
  44         unsigned char ip_src[4];
  45         unsigned char mac_dst[ETH_ALEN];
  46         unsigned char ip_dst[4];
  47 };
  48
  49 static void print_MAC(unsigned char *p)
  50 {
  51         int i;
  52
  53         for (i = 0; i < ETH_ALEN; i++, p++)
  54                 printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
  55 }
  56
  57 #define myNIPQUAD(a) a[0], a[1], a[2], a[3]
  58 static void ebt_log(const struct sk_buff *skb, const struct net_device *in,
  59    const struct net_device *out, const void *data, unsigned int datalen)
  60 {
  61         struct ebt_log_info *info = (struct ebt_log_info *)data;
  62         char level_string[4] = "< >";
  63         union {struct iphdr iph; struct tcpudphdr ports;
  64                struct arphdr arph; struct arppayload arpp;} u;
  65
  66         level_string[1] = '0' + info->loglevel;
  67         spin_lock_bh(&ebt_log_lock);
  68         printk(level_string);
  69         printk("%s IN=%s OUT=%s ", info->prefix, in ? in->name : "",
  70            out ? out->name : "");
  71
  72         printk("MAC source = ");
  73         print_MAC((skb->mac.ethernet)->h_source);
  74         printk("MAC dest = ");
  75         print_MAC((skb->mac.ethernet)->h_dest);
  76
  77         printk("proto = 0x%04x", ntohs(((*skb).mac.ethernet)->h_proto));
  78
  79         if ((info->bitmask & EBT_LOG_IP) && skb->mac.ethernet->h_proto ==
  80            htons(ETH_P_IP)){
  81                 if (skb_copy_bits(skb, 0, &u.iph, sizeof(u.iph))) {
  82                         printk(" INCOMPLETE IP header");
  83                         goto out;
  84                 }
  85                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u,",
  86                    NIPQUAD(u.iph.saddr), NIPQUAD(u.iph.daddr));
  87                 printk(" IP tos=0x%02X, IP proto=%d", u.iph.tos,
  88                        u.iph.protocol);
  89                 if (u.iph.protocol == IPPROTO_TCP ||
  90                     u.iph.protocol == IPPROTO_UDP) {
  91                         if (skb_copy_bits(skb, u.iph.ihl*4, &u.ports,
  92                             sizeof(u.ports))) {
  93                                 printk(" INCOMPLETE TCP/UDP header");
  94                                 goto out;
  95                         }
  96                         printk(" SPT=%u DPT=%u", ntohs(u.ports.src),
  97                            ntohs(u.ports.dst));
  98                 }
  99                 goto out;
 100         }
 101
 102         if ((info->bitmask & EBT_LOG_ARP) &&
 103             ((skb->mac.ethernet->h_proto == __constant_htons(ETH_P_ARP)) ||
 104             (skb->mac.ethernet->h_proto == __constant_htons(ETH_P_RARP)))) {
 105                 if (skb_copy_bits(skb, 0, &u.arph, sizeof(u.arph))) {
 106                         printk(" INCOMPLETE ARP header");
 107                         goto out;
 108                 }
 109                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 110                        ntohs(u.arph.ar_hrd), ntohs(u.arph.ar_pro),
 111                        ntohs(u.arph.ar_op));
 112
 113                 /* If it's for Ethernet and the lengths are OK,
 114                  * then log the ARP payload */
 115                 if (u.arph.ar_hrd == __constant_htons(1) &&
 116                     u.arph.ar_hln == ETH_ALEN &&
 117                     u.arph.ar_pln == sizeof(uint32_t)) {
 118                         if (skb_copy_bits(skb, sizeof(u.arph), &u.arpp,
 119                             sizeof(u.arpp))) {
 120                                 printk(" INCOMPLETE ARP payload");
 121                                 goto out;
 122                         }
 123                         printk(" ARP MAC SRC=");
 124                         print_MAC(u.arpp.mac_src);
 125                         printk(" ARP IP SRC=%u.%u.%u.%u",
 126                                myNIPQUAD(u.arpp.ip_src));
 127                         printk(" ARP MAC DST=");
 128                         print_MAC(u.arpp.mac_dst);
 129                         printk(" ARP IP DST=%u.%u.%u.%u",
 130                                myNIPQUAD(u.arpp.ip_dst));
 131                 }
 132         }
 133 out:
 134         printk("\n");
 135         spin_unlock_bh(&ebt_log_lock);
 136 }
 137
 138 static struct ebt_watcher log =
 139 {
 140         .name           = EBT_LOG_WATCHER,
 141         .watcher        = ebt_log,
 142         .check          = ebt_log_check,
 143         .me             = THIS_MODULE,
 144 };
 145
 146 static int __init init(void)
 147 {
 148         return ebt_register_watcher(&log);
 149 }
 150
 151 static void __exit fini(void)
 152 {
 153         ebt_unregister_watcher(&log);
 154 }
 155
 156 module_init(init);
 157 module_exit(fini);
 158 MODULE_LICENSE("GPL");