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 #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 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 false;
  33         if (info->loglevel >= 8)
  34                 return false;
  35         info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
  36         return true;
  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 static void
  62 print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
  63 {
  64         if (protocol == IPPROTO_TCP ||
  65             protocol == IPPROTO_UDP ||
  66             protocol == IPPROTO_UDPLITE ||
  67             protocol == IPPROTO_SCTP ||
  68             protocol == IPPROTO_DCCP) {
  69                 const struct tcpudphdr *pptr;
  70                 struct tcpudphdr _ports;
  71
  72                 pptr = skb_header_pointer(skb, offset,
  73                                           sizeof(_ports), &_ports);
  74                 if (pptr == NULL) {
  75                         printk(" INCOMPLETE TCP/UDP header");
  76                         return;
  77                 }
  78                 printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
  79         }
  80 }
  81
  82 #define myNIPQUAD(a) a[0], a[1], a[2], a[3]
  83 static void
  84 ebt_log_packet(u_int8_t pf, unsigned int hooknum,
  85    const struct sk_buff *skb, const struct net_device *in,
  86    const struct net_device *out, const struct nf_loginfo *loginfo,
  87    const char *prefix)
  88 {
  89         unsigned int bitmask;
  90
  91         spin_lock_bh(&ebt_log_lock);
  92         printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
  93                prefix, in ? in->name : "", out ? out->name : "");
  94
  95         print_MAC(eth_hdr(skb)->h_source);
  96         printk("MAC dest = ");
  97         print_MAC(eth_hdr(skb)->h_dest);
  98
  99         printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
 100
 101         if (loginfo->type == NF_LOG_TYPE_LOG)
 102                 bitmask = loginfo->u.log.logflags;
 103         else
 104                 bitmask = NF_LOG_MASK;
 105
 106         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
 107            htons(ETH_P_IP)){
 108                 const struct iphdr *ih;
 109                 struct iphdr _iph;
 110
 111                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 112                 if (ih == NULL) {
 113                         printk(" INCOMPLETE IP header");
 114                         goto out;
 115                 }
 116                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
 117                        "tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
 118                        NIPQUAD(ih->daddr), ih->tos, ih->protocol);
 119                 print_ports(skb, ih->protocol, ih->ihl*4);
 120                 goto out;
 121         }
 122
 123 #if defined(CONFIG_BRIDGE_EBT_IP6) || defined(CONFIG_BRIDGE_EBT_IP6_MODULE)
 124         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 125            htons(ETH_P_IPV6)) {
 126                 const struct ipv6hdr *ih;
 127                 struct ipv6hdr _iph;
 128                 uint8_t nexthdr;
 129                 int offset_ph;
 130
 131                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 132                 if (ih == NULL) {
 133                         printk(" INCOMPLETE IPv6 header");
 134                         goto out;
 135                 }
 136                 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 137                        &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 138                 nexthdr = ih->nexthdr;
 139                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr);
 140                 if (offset_ph == -1)
 141                         goto out;
 142                 print_ports(skb, nexthdr, offset_ph);
 143                 goto out;
 144         }
 145 #endif
 146
 147         if ((bitmask & EBT_LOG_ARP) &&
 148             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 149              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 150                 const struct arphdr *ah;
 151                 struct arphdr _arph;
 152
 153                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 154                 if (ah == NULL) {
 155                         printk(" INCOMPLETE ARP header");
 156                         goto out;
 157                 }
 158                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 159                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 160                        ntohs(ah->ar_op));
 161
 162                 /* If it's for Ethernet and the lengths are OK,
 163                  * then log the ARP payload */
 164                 if (ah->ar_hrd == htons(1) &&
 165                     ah->ar_hln == ETH_ALEN &&
 166                     ah->ar_pln == sizeof(__be32)) {
 167                         const struct arppayload *ap;
 168                         struct arppayload _arpp;
 169
 170                         ap = skb_header_pointer(skb, sizeof(_arph),
 171                                                 sizeof(_arpp), &_arpp);
 172                         if (ap == NULL) {
 173                                 printk(" INCOMPLETE ARP payload");
 174                                 goto out;
 175                         }
 176                         printk(" ARP MAC SRC=");
 177                         print_MAC(ap->mac_src);
 178                         printk(" ARP IP SRC=%u.%u.%u.%u",
 179                                myNIPQUAD(ap->ip_src));
 180                         printk(" ARP MAC DST=");
 181                         print_MAC(ap->mac_dst);
 182                         printk(" ARP IP DST=%u.%u.%u.%u",
 183                                myNIPQUAD(ap->ip_dst));
 184                 }
 185         }
 186 out:
 187         printk("\n");
 188         spin_unlock_bh(&ebt_log_lock);
 189
 190 }
 191
 192 static unsigned int
 193 ebt_log_tg(struct sk_buff *skb, const struct xt_target_param *par)
 194 {
 195         const struct ebt_log_info *info = par->targinfo;
 196         struct nf_loginfo li;
 197
 198         li.type = NF_LOG_TYPE_LOG;
 199         li.u.log.level = info->loglevel;
 200         li.u.log.logflags = info->bitmask;
 201
 202         if (info->bitmask & EBT_LOG_NFLOG)
 203                 nf_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 204                               par->out, &li, "%s", info->prefix);
 205         else
 206                 ebt_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 207                                par->out, &li, info->prefix);
 208         return EBT_CONTINUE;
 209 }
 210
 211 static struct xt_target ebt_log_tg_reg __read_mostly = {
 212         .name           = "log",
 213         .revision       = 0,
 214         .family         = NFPROTO_BRIDGE,
 215         .target         = ebt_log_tg,
 216         .checkentry     = ebt_log_tg_check,
 217         .targetsize     = XT_ALIGN(sizeof(struct ebt_log_info)),
 218         .me             = THIS_MODULE,
 219 };
 220
 221 static const struct nf_logger ebt_log_logger = {
 222         .name           = "ebt_log",
 223         .logfn          = &ebt_log_packet,
 224         .me             = THIS_MODULE,
 225 };
 226
 227 static int __init ebt_log_init(void)
 228 {
 229         int ret;
 230
 231         ret = xt_register_target(&ebt_log_tg_reg);
 232         if (ret < 0)
 233                 return ret;
 234         nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
 235         return 0;
 236 }
 237
 238 static void __exit ebt_log_fini(void)
 239 {
 240         nf_log_unregister(&ebt_log_logger);
 241         xt_unregister_target(&ebt_log_tg_reg);
 242 }
 243
 244 module_init(ebt_log_init);
 245 module_exit(ebt_log_fini);
 246 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 247 MODULE_LICENSE("GPL");