net/bridge/netfilter/ebt_log.c

   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/in.h>
  13 #include <linux/netfilter_bridge/ebtables.h>
  14 #include <linux/netfilter_bridge/ebt_log.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/module.h>
  17 #include <linux/ip.h>
  18 #include <linux/in.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/spinlock.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 = (struct ebt_log_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(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                 struct iphdr _iph, *ih;
  88
  89                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
  90                 if (ih == NULL) {
  91                         printk(" INCOMPLETE IP header");
  92                         goto out;
  93                 }
  94                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
  95                        "tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
  96                        NIPQUAD(ih->daddr), ih->tos, ih->protocol);
  97                 if (ih->protocol == IPPROTO_TCP ||
  98                     ih->protocol == IPPROTO_UDP ||
  99                     ih->protocol == IPPROTO_UDPLITE ||
 100                     ih->protocol == IPPROTO_SCTP ||
 101                     ih->protocol == IPPROTO_DCCP) {
 102                         struct tcpudphdr _ports, *pptr;
 103
 104                         pptr = skb_header_pointer(skb, ih->ihl*4,
 105                                                   sizeof(_ports), &_ports);
 106                         if (pptr == NULL) {
 107                                 printk(" INCOMPLETE TCP/UDP header");
 108                                 goto out;
 109                         }
 110                         printk(" SPT=%u DPT=%u", ntohs(pptr->src),
 111                            ntohs(pptr->dst));
 112                 }
 113                 goto out;
 114         }
 115
 116         if ((bitmask & EBT_LOG_ARP) &&
 117             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 118              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 119                 struct arphdr _arph, *ah;
 120
 121                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 122                 if (ah == NULL) {
 123                         printk(" INCOMPLETE ARP header");
 124                         goto out;
 125                 }
 126                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 127                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 128                        ntohs(ah->ar_op));
 129
 130                 /* If it's for Ethernet and the lengths are OK,
 131                  * then log the ARP payload */
 132                 if (ah->ar_hrd == htons(1) &&
 133                     ah->ar_hln == ETH_ALEN &&
 134                     ah->ar_pln == sizeof(__be32)) {
 135                         struct arppayload _arpp, *ap;
 136
 137                         ap = skb_header_pointer(skb, sizeof(_arph),
 138                                                 sizeof(_arpp), &_arpp);
 139                         if (ap == NULL) {
 140                                 printk(" INCOMPLETE ARP payload");
 141                                 goto out;
 142                         }
 143                         printk(" ARP MAC SRC=");
 144                         print_MAC(ap->mac_src);
 145                         printk(" ARP IP SRC=%u.%u.%u.%u",
 146                                myNIPQUAD(ap->ip_src));
 147                         printk(" ARP MAC DST=");
 148                         print_MAC(ap->mac_dst);
 149                         printk(" ARP IP DST=%u.%u.%u.%u",
 150                                myNIPQUAD(ap->ip_dst));
 151                 }
 152         }
 153 out:
 154         printk("\n");
 155         spin_unlock_bh(&ebt_log_lock);
 156
 157 }
 158
 159 static void ebt_log(const struct sk_buff *skb, unsigned int hooknr,
 160    const struct net_device *in, const struct net_device *out,
 161    const void *data, unsigned int datalen)
 162 {
 163         struct ebt_log_info *info = (struct ebt_log_info *)data;
 164         struct nf_loginfo li;
 165
 166         li.type = NF_LOG_TYPE_LOG;
 167         li.u.log.level = info->loglevel;
 168         li.u.log.logflags = info->bitmask;
 169
 170         if (info->bitmask & EBT_LOG_NFLOG)
 171                 nf_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
 172                               "%s", info->prefix);
 173         else
 174                 ebt_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
 175                                info->prefix);
 176 }
 177
 178 static struct ebt_watcher log =
 179 {
 180         .name           = EBT_LOG_WATCHER,
 181         .watcher        = ebt_log,
 182         .check          = ebt_log_check,
 183         .me             = THIS_MODULE,
 184 };
 185
 186 static struct nf_logger ebt_log_logger = {
 187         .name           = "ebt_log",
 188         .logfn          = &ebt_log_packet,
 189         .me             = THIS_MODULE,
 190 };
 191
 192 static int __init ebt_log_init(void)
 193 {
 194         int ret;
 195
 196         ret = ebt_register_watcher(&log);
 197         if (ret < 0)
 198                 return ret;
 199         if (nf_log_register(PF_BRIDGE, &ebt_log_logger) < 0) {
 200                 printk(KERN_WARNING "ebt_log: not logging via system console "
 201                        "since somebody else already registered for PF_INET\n");
 202                 /* we cannot make module load fail here, since otherwise
 203                  * ebtables userspace would abort */
 204         }
 205
 206         return 0;
 207 }
 208
 209 static void __exit ebt_log_fini(void)
 210 {
 211         nf_log_unregister(&ebt_log_logger);
 212         ebt_unregister_watcher(&log);
 213 }
 214
 215 module_init(ebt_log_init);
 216 module_exit(ebt_log_fini);
 217 MODULE_LICENSE("GPL");