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(struct net *net, 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         /* FIXME: Disabled from containers until syslog ns is supported */
  83         if (!net_eq(net, &init_net))
  84                 return;
  85
  86         spin_lock_bh(&ebt_log_lock);
  87         printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
  88                '0' + loginfo->u.log.level, prefix,
  89                in ? in->name : "", out ? out->name : "",
  90                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
  91                ntohs(eth_hdr(skb)->h_proto));
  92
  93         if (loginfo->type == NF_LOG_TYPE_LOG)
  94                 bitmask = loginfo->u.log.logflags;
  95         else
  96                 bitmask = NF_LOG_MASK;
  97
  98         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  99            htons(ETH_P_IP)) {
 100                 const struct iphdr *ih;
 101                 struct iphdr _iph;
 102
 103                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 104                 if (ih == NULL) {
 105                         printk(" INCOMPLETE IP header");
 106                         goto out;
 107                 }
 108                 printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
 109                        &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
 110                 print_ports(skb, ih->protocol, ih->ihl*4);
 111                 goto out;
 112         }
 113
 114 #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
 115         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 116            htons(ETH_P_IPV6)) {
 117                 const struct ipv6hdr *ih;
 118                 struct ipv6hdr _iph;
 119                 uint8_t nexthdr;
 120                 __be16 frag_off;
 121                 int offset_ph;
 122
 123                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 124                 if (ih == NULL) {
 125                         printk(" INCOMPLETE IPv6 header");
 126                         goto out;
 127                 }
 128                 printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 129                        &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 130                 nexthdr = ih->nexthdr;
 131                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
 132                 if (offset_ph == -1)
 133                         goto out;
 134                 print_ports(skb, nexthdr, offset_ph);
 135                 goto out;
 136         }
 137 #endif
 138
 139         if ((bitmask & EBT_LOG_ARP) &&
 140             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 141              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 142                 const struct arphdr *ah;
 143                 struct arphdr _arph;
 144
 145                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 146                 if (ah == NULL) {
 147                         printk(" INCOMPLETE ARP header");
 148                         goto out;
 149                 }
 150                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 151                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 152                        ntohs(ah->ar_op));
 153
 154                 /* If it's for Ethernet and the lengths are OK,
 155                  * then log the ARP payload */
 156                 if (ah->ar_hrd == htons(1) &&
 157                     ah->ar_hln == ETH_ALEN &&
 158                     ah->ar_pln == sizeof(__be32)) {
 159                         const struct arppayload *ap;
 160                         struct arppayload _arpp;
 161
 162                         ap = skb_header_pointer(skb, sizeof(_arph),
 163                                                 sizeof(_arpp), &_arpp);
 164                         if (ap == NULL) {
 165                                 printk(" INCOMPLETE ARP payload");
 166                                 goto out;
 167                         }
 168                         printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
 169                                         ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
 170                 }
 171         }
 172 out:
 173         printk("\n");
 174         spin_unlock_bh(&ebt_log_lock);
 175
 176 }
 177
 178 static unsigned int
 179 ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 180 {
 181         const struct ebt_log_info *info = par->targinfo;
 182         struct nf_loginfo li;
 183         struct net *net = par->net;
 184
 185         li.type = NF_LOG_TYPE_LOG;
 186         li.u.log.level = info->loglevel;
 187         li.u.log.logflags = info->bitmask;
 188
 189         /* Remember that we have to use ebt_log_packet() not to break backward
 190          * compatibility. We cannot use the default bridge packet logger via
 191          * nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
 192          */
 193         if (info->bitmask & EBT_LOG_NFLOG)
 194                 nf_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb,
 195                               par->in, par->out, &li, "%s", info->prefix);
 196         else
 197                 ebt_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb, par->in,
 198                                par->out, &li, info->prefix);
 199         return EBT_CONTINUE;
 200 }
 201
 202 static struct xt_target ebt_log_tg_reg __read_mostly = {
 203         .name           = "log",
 204         .revision       = 0,
 205         .family         = NFPROTO_BRIDGE,
 206         .target         = ebt_log_tg,
 207         .checkentry     = ebt_log_tg_check,
 208         .targetsize     = sizeof(struct ebt_log_info),
 209         .me             = THIS_MODULE,
 210 };
 211
 212 static int __init ebt_log_init(void)
 213 {
 214         return xt_register_target(&ebt_log_tg_reg);
 215 }
 216
 217 static void __exit ebt_log_fini(void)
 218 {
 219         xt_unregister_target(&ebt_log_tg_reg);
 220 }
 221
 222 module_init(ebt_log_init);
 223 module_exit(ebt_log_fini);
 224 MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 225 MODULE_LICENSE("GPL");