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 int 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 -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
  54 print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
  55 {
  56         if (protocol == IPPROTO_TCP ||
  57             protocol == IPPROTO_UDP ||
  58             protocol == IPPROTO_UDPLITE ||
  59             protocol == IPPROTO_SCTP ||
  60             protocol == IPPROTO_DCCP) {
  61                 const struct tcpudphdr *pptr;
  62                 struct tcpudphdr _ports;
  63
  64                 pptr = skb_header_pointer(skb, offset,
  65                                           sizeof(_ports), &_ports);
  66                 if (pptr == NULL) {
  67                         printk(" INCOMPLETE TCP/UDP header");
  68                         return;
  69                 }
  70                 printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
  71         }
  72 }
  73
  74 static void
  75 ebt_log_packet(u_int8_t pf, unsigned int hooknum,
  76    const struct sk_buff *skb, const struct net_device *in,
  77    const struct net_device *out, const struct nf_loginfo *loginfo,
  78    const char *prefix)
  79 {
  80         unsigned int bitmask;
  81         struct net *net = dev_net(in ? in : out);
  82
  83         /* FIXME: Disabled from containers until syslog ns is supported */
  84         if (!net_eq(net, &init_net))
  85                 return;
  86
  87         spin_lock_bh(&ebt_log_lock);
  88         printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
  89                '0' + loginfo->u.log.level, prefix,
  90                in ? in->name : "", out ? out->name : "",
  91                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
  92                ntohs(eth_hdr(skb)->h_proto));
  93
  94         if (loginfo->type == NF_LOG_TYPE_LOG)
  95                 bitmask = loginfo->u.log.logflags;
  96         else
  97                 bitmask = NF_LOG_MASK;
  98
  99         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
 100            htons(ETH_P_IP)){
 101                 const struct iphdr *ih;
 102                 struct iphdr _iph;
 103
 104                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 105                 if (ih == NULL) {
 106                         printk(" INCOMPLETE IP header");
 107                         goto out;
 108                 }
 109                 printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
 110                        &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
 111                 print_ports(skb, ih->protocol, ih->ihl*4);
 112                 goto out;
 113         }
 114
 115 #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
 116         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 117            htons(ETH_P_IPV6)) {
 118                 const struct ipv6hdr *ih;
 119                 struct ipv6hdr _iph;
 120                 uint8_t nexthdr;
 121                 __be16 frag_off;
 122                 int offset_ph;
 123
 124                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 125                 if (ih == NULL) {
 126                         printk(" INCOMPLETE IPv6 header");
 127                         goto out;
 128                 }
 129                 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 130                        &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 131                 nexthdr = ih->nexthdr;
 132                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
 133                 if (offset_ph == -1)
 134                         goto out;
 135                 print_ports(skb, nexthdr, offset_ph);
 136                 goto out;
 137         }
 138 #endif
 139
 140         if ((bitmask & EBT_LOG_ARP) &&
 141             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 142              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 143                 const struct arphdr *ah;
 144                 struct arphdr _arph;
 145
 146                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 147                 if (ah == NULL) {
 148                         printk(" INCOMPLETE ARP header");
 149                         goto out;
 150                 }
 151                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 152                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 153                        ntohs(ah->ar_op));
 154
 155                 /* If it's for Ethernet and the lengths are OK,
 156                  * then log the ARP payload */
 157                 if (ah->ar_hrd == htons(1) &&
 158                     ah->ar_hln == ETH_ALEN &&
 159                     ah->ar_pln == sizeof(__be32)) {
 160                         const struct arppayload *ap;
 161                         struct arppayload _arpp;
 162
 163                         ap = skb_header_pointer(skb, sizeof(_arph),
 164                                                 sizeof(_arpp), &_arpp);
 165                         if (ap == NULL) {
 166                                 printk(" INCOMPLETE ARP payload");
 167                                 goto out;
 168                         }
 169                         printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
 170                                         ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
 171                 }
 172         }
 173 out:
 174         printk("\n");
 175         spin_unlock_bh(&ebt_log_lock);
 176
 177 }
 178
 179 static unsigned int
 180 ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 181 {
 182         const struct ebt_log_info *info = par->targinfo;
 183         struct nf_loginfo li;
 184         struct net *net = dev_net(par->in ? par->in : par->out);
 185
 186         li.type = NF_LOG_TYPE_LOG;
 187         li.u.log.level = info->loglevel;
 188         li.u.log.logflags = info->bitmask;
 189
 190         if (info->bitmask & EBT_LOG_NFLOG)
 191                 nf_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb,
 192                               par->in, par->out, &li, "%s", info->prefix);
 193         else
 194                 ebt_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 195                                par->out, &li, info->prefix);
 196         return EBT_CONTINUE;
 197 }
 198
 199 static struct xt_target ebt_log_tg_reg __read_mostly = {
 200         .name           = "log",
 201         .revision       = 0,
 202         .family         = NFPROTO_BRIDGE,
 203         .target         = ebt_log_tg,
 204         .checkentry     = ebt_log_tg_check,
 205         .targetsize     = sizeof(struct ebt_log_info),
 206         .me             = THIS_MODULE,
 207 };
 208
 209 static struct nf_logger ebt_log_logger __read_mostly = {
 210         .name           = "ebt_log",
 211         .logfn          = &ebt_log_packet,
 212         .me             = THIS_MODULE,
 213 };
 214
 215 static int __net_init ebt_log_net_init(struct net *net)
 216 {
 217         nf_log_set(net, NFPROTO_BRIDGE, &ebt_log_logger);
 218         return 0;
 219 }
 220
 221 static void __net_exit ebt_log_net_fini(struct net *net)
 222 {
 223         nf_log_unset(net, &ebt_log_logger);
 224 }
 225
 226 static struct pernet_operations ebt_log_net_ops = {
 227         .init = ebt_log_net_init,
 228         .exit = ebt_log_net_fini,
 229 };
 230
 231 static int __init ebt_log_init(void)
 232 {
 233         int ret;
 234
 235         ret = register_pernet_subsys(&ebt_log_net_ops);
 236         if (ret < 0)
 237                 goto err_pernet;
 238
 239         ret = xt_register_target(&ebt_log_tg_reg);
 240         if (ret < 0)
 241                 goto err_target;
 242
 243         nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
 244
 245         return ret;
 246
 247 err_target:
 248         unregister_pernet_subsys(&ebt_log_net_ops);
 249 err_pernet:
 250         return ret;
 251 }
 252
 253 static void __exit ebt_log_fini(void)
 254 {
 255         unregister_pernet_subsys(&ebt_log_net_ops);
 256         nf_log_unregister(&ebt_log_logger);
 257         xt_unregister_target(&ebt_log_tg_reg);
 258 }
 259
 260 module_init(ebt_log_init);
 261 module_exit(ebt_log_fini);
 262 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 263 MODULE_LICENSE("GPL");