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 static void
  83 ebt_log_packet(u_int8_t pf, unsigned int hooknum,
  84    const struct sk_buff *skb, const struct net_device *in,
  85    const struct net_device *out, const struct nf_loginfo *loginfo,
  86    const char *prefix)
  87 {
  88         unsigned int bitmask;
  89
  90         spin_lock_bh(&ebt_log_lock);
  91         printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
  92                prefix, in ? in->name : "", out ? out->name : "");
  93
  94         print_MAC(eth_hdr(skb)->h_source);
  95         printk("MAC dest = ");
  96         print_MAC(eth_hdr(skb)->h_dest);
  97
  98         printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
  99
 100         if (loginfo->type == NF_LOG_TYPE_LOG)
 101                 bitmask = loginfo->u.log.logflags;
 102         else
 103                 bitmask = NF_LOG_MASK;
 104
 105         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
 106            htons(ETH_P_IP)){
 107                 const struct iphdr *ih;
 108                 struct iphdr _iph;
 109
 110                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 111                 if (ih == NULL) {
 112                         printk(" INCOMPLETE IP header");
 113                         goto out;
 114                 }
 115                 printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
 116                        &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
 117                 print_ports(skb, ih->protocol, ih->ihl*4);
 118                 goto out;
 119         }
 120
 121 #if defined(CONFIG_BRIDGE_EBT_IP6) || defined(CONFIG_BRIDGE_EBT_IP6_MODULE)
 122         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 123            htons(ETH_P_IPV6)) {
 124                 const struct ipv6hdr *ih;
 125                 struct ipv6hdr _iph;
 126                 uint8_t nexthdr;
 127                 int offset_ph;
 128
 129                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 130                 if (ih == NULL) {
 131                         printk(" INCOMPLETE IPv6 header");
 132                         goto out;
 133                 }
 134                 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 135                        &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 136                 nexthdr = ih->nexthdr;
 137                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr);
 138                 if (offset_ph == -1)
 139                         goto out;
 140                 print_ports(skb, nexthdr, offset_ph);
 141                 goto out;
 142         }
 143 #endif
 144
 145         if ((bitmask & EBT_LOG_ARP) &&
 146             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 147              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 148                 const struct arphdr *ah;
 149                 struct arphdr _arph;
 150
 151                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 152                 if (ah == NULL) {
 153                         printk(" INCOMPLETE ARP header");
 154                         goto out;
 155                 }
 156                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 157                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 158                        ntohs(ah->ar_op));
 159
 160                 /* If it's for Ethernet and the lengths are OK,
 161                  * then log the ARP payload */
 162                 if (ah->ar_hrd == htons(1) &&
 163                     ah->ar_hln == ETH_ALEN &&
 164                     ah->ar_pln == sizeof(__be32)) {
 165                         const struct arppayload *ap;
 166                         struct arppayload _arpp;
 167
 168                         ap = skb_header_pointer(skb, sizeof(_arph),
 169                                                 sizeof(_arpp), &_arpp);
 170                         if (ap == NULL) {
 171                                 printk(" INCOMPLETE ARP payload");
 172                                 goto out;
 173                         }
 174                         printk(" ARP MAC SRC=");
 175                         print_MAC(ap->mac_src);
 176                         printk(" ARP IP SRC=%pI4", ap->ip_src);
 177                         printk(" ARP MAC DST=");
 178                         print_MAC(ap->mac_dst);
 179                         printk(" ARP IP DST=%pI4", ap->ip_dst);
 180                 }
 181         }
 182 out:
 183         printk("\n");
 184         spin_unlock_bh(&ebt_log_lock);
 185
 186 }
 187
 188 static unsigned int
 189 ebt_log_tg(struct sk_buff *skb, const struct xt_target_param *par)
 190 {
 191         const struct ebt_log_info *info = par->targinfo;
 192         struct nf_loginfo li;
 193
 194         li.type = NF_LOG_TYPE_LOG;
 195         li.u.log.level = info->loglevel;
 196         li.u.log.logflags = info->bitmask;
 197
 198         if (info->bitmask & EBT_LOG_NFLOG)
 199                 nf_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 200                               par->out, &li, "%s", info->prefix);
 201         else
 202                 ebt_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 203                                par->out, &li, info->prefix);
 204         return EBT_CONTINUE;
 205 }
 206
 207 static struct xt_target ebt_log_tg_reg __read_mostly = {
 208         .name           = "log",
 209         .revision       = 0,
 210         .family         = NFPROTO_BRIDGE,
 211         .target         = ebt_log_tg,
 212         .checkentry     = ebt_log_tg_check,
 213         .targetsize     = XT_ALIGN(sizeof(struct ebt_log_info)),
 214         .me             = THIS_MODULE,
 215 };
 216
 217 static const struct nf_logger ebt_log_logger = {
 218         .name           = "ebt_log",
 219         .logfn          = &ebt_log_packet,
 220         .me             = THIS_MODULE,
 221 };
 222
 223 static int __init ebt_log_init(void)
 224 {
 225         int ret;
 226
 227         ret = xt_register_target(&ebt_log_tg_reg);
 228         if (ret < 0)
 229                 return ret;
 230         nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
 231         return 0;
 232 }
 233
 234 static void __exit ebt_log_fini(void)
 235 {
 236         nf_log_unregister(&ebt_log_logger);
 237         xt_unregister_target(&ebt_log_tg_reg);
 238 }
 239
 240 module_init(ebt_log_init);
 241 module_exit(ebt_log_fini);
 242 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 243 MODULE_LICENSE("GPL");