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
  82         spin_lock_bh(&ebt_log_lock);
  83         printk("<%c>%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
  84                '0' + loginfo->u.log.level, prefix,
  85                in ? in->name : "", out ? out->name : "",
  86                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
  87                ntohs(eth_hdr(skb)->h_proto));
  88
  89         if (loginfo->type == NF_LOG_TYPE_LOG)
  90                 bitmask = loginfo->u.log.logflags;
  91         else
  92                 bitmask = NF_LOG_MASK;
  93
  94         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  95            htons(ETH_P_IP)){
  96                 const struct iphdr *ih;
  97                 struct iphdr _iph;
  98
  99                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 100                 if (ih == NULL) {
 101                         printk(" INCOMPLETE IP header");
 102                         goto out;
 103                 }
 104                 printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
 105                        &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
 106                 print_ports(skb, ih->protocol, ih->ihl*4);
 107                 goto out;
 108         }
 109
 110 #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
 111         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 112            htons(ETH_P_IPV6)) {
 113                 const struct ipv6hdr *ih;
 114                 struct ipv6hdr _iph;
 115                 uint8_t nexthdr;
 116                 __be16 frag_off;
 117                 int offset_ph;
 118
 119                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 120                 if (ih == NULL) {
 121                         printk(" INCOMPLETE IPv6 header");
 122                         goto out;
 123                 }
 124                 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 125                        &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 126                 nexthdr = ih->nexthdr;
 127                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
 128                 if (offset_ph == -1)
 129                         goto out;
 130                 print_ports(skb, nexthdr, offset_ph);
 131                 goto out;
 132         }
 133 #endif
 134
 135         if ((bitmask & EBT_LOG_ARP) &&
 136             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 137              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 138                 const struct arphdr *ah;
 139                 struct arphdr _arph;
 140
 141                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 142                 if (ah == NULL) {
 143                         printk(" INCOMPLETE ARP header");
 144                         goto out;
 145                 }
 146                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 147                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 148                        ntohs(ah->ar_op));
 149
 150                 /* If it's for Ethernet and the lengths are OK,
 151                  * then log the ARP payload */
 152                 if (ah->ar_hrd == htons(1) &&
 153                     ah->ar_hln == ETH_ALEN &&
 154                     ah->ar_pln == sizeof(__be32)) {
 155                         const struct arppayload *ap;
 156                         struct arppayload _arpp;
 157
 158                         ap = skb_header_pointer(skb, sizeof(_arph),
 159                                                 sizeof(_arpp), &_arpp);
 160                         if (ap == NULL) {
 161                                 printk(" INCOMPLETE ARP payload");
 162                                 goto out;
 163                         }
 164                         printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
 165                                         ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
 166                 }
 167         }
 168 out:
 169         printk("\n");
 170         spin_unlock_bh(&ebt_log_lock);
 171
 172 }
 173
 174 static unsigned int
 175 ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 176 {
 177         const struct ebt_log_info *info = par->targinfo;
 178         struct nf_loginfo li;
 179
 180         li.type = NF_LOG_TYPE_LOG;
 181         li.u.log.level = info->loglevel;
 182         li.u.log.logflags = info->bitmask;
 183
 184         if (info->bitmask & EBT_LOG_NFLOG)
 185                 nf_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 186                               par->out, &li, "%s", info->prefix);
 187         else
 188                 ebt_log_packet(NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 189                                par->out, &li, info->prefix);
 190         return EBT_CONTINUE;
 191 }
 192
 193 static struct xt_target ebt_log_tg_reg __read_mostly = {
 194         .name           = "log",
 195         .revision       = 0,
 196         .family         = NFPROTO_BRIDGE,
 197         .target         = ebt_log_tg,
 198         .checkentry     = ebt_log_tg_check,
 199         .targetsize     = sizeof(struct ebt_log_info),
 200         .me             = THIS_MODULE,
 201 };
 202
 203 static struct nf_logger ebt_log_logger __read_mostly = {
 204         .name           = "ebt_log",
 205         .logfn          = &ebt_log_packet,
 206         .me             = THIS_MODULE,
 207 };
 208
 209 static int __init ebt_log_init(void)
 210 {
 211         int ret;
 212
 213         ret = xt_register_target(&ebt_log_tg_reg);
 214         if (ret < 0)
 215                 return ret;
 216         nf_log_register(NFPROTO_BRIDGE, &ebt_log_logger);
 217         return 0;
 218 }
 219
 220 static void __exit ebt_log_fini(void)
 221 {
 222         nf_log_unregister(&ebt_log_logger);
 223         xt_unregister_target(&ebt_log_tg_reg);
 224 }
 225
 226 module_init(ebt_log_init);
 227 module_exit(ebt_log_fini);
 228 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 229 MODULE_LICENSE("GPL");