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         __be16 src;
  41         __be16 dst;
  42 };
  43
  44 struct arppayload {
  45         unsigned char mac_src[ETH_ALEN];
  46         unsigned char ip_src[4];
  47         unsigned char mac_dst[ETH_ALEN];
  48         unsigned char ip_dst[4];
  49 };
  50
  51 static void
  52 print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
  53 {
  54         if (protocol == IPPROTO_TCP ||
  55             protocol == IPPROTO_UDP ||
  56             protocol == IPPROTO_UDPLITE ||
  57             protocol == IPPROTO_SCTP ||
  58             protocol == IPPROTO_DCCP) {
  59                 const struct tcpudphdr *pptr;
  60                 struct tcpudphdr _ports;
  61
  62                 pptr = skb_header_pointer(skb, offset,
  63                                           sizeof(_ports), &_ports);
  64                 if (pptr == NULL) {
  65                         pr_cont(" INCOMPLETE TCP/UDP header");
  66                         return;
  67                 }
  68                 pr_cont(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
  69         }
  70 }
  71
  72 static void
  73 ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum,
  74                const struct sk_buff *skb, const struct net_device *in,
  75                const struct net_device *out, const struct nf_loginfo *loginfo,
  76                const char *prefix)
  77 {
  78         unsigned int bitmask;
  79
  80         /* FIXME: Disabled from containers until syslog ns is supported */
  81         if (!net_eq(net, &init_net) && !sysctl_nf_log_all_netns)
  82                 return;
  83
  84         spin_lock_bh(&ebt_log_lock);
  85         printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
  86                '0' + loginfo->u.log.level, prefix,
  87                in ? in->name : "", out ? out->name : "",
  88                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
  89                ntohs(eth_hdr(skb)->h_proto));
  90
  91         if (loginfo->type == NF_LOG_TYPE_LOG)
  92                 bitmask = loginfo->u.log.logflags;
  93         else
  94                 bitmask = NF_LOG_DEFAULT_MASK;
  95
  96         if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  97            htons(ETH_P_IP)) {
  98                 const struct iphdr *ih;
  99                 struct iphdr _iph;
 100
 101                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 102                 if (ih == NULL) {
 103                         pr_cont(" INCOMPLETE IP header");
 104                         goto out;
 105                 }
 106                 pr_cont(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
 107                         &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
 108                 print_ports(skb, ih->protocol, ih->ihl*4);
 109                 goto out;
 110         }
 111
 112 #if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
 113         if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
 114            htons(ETH_P_IPV6)) {
 115                 const struct ipv6hdr *ih;
 116                 struct ipv6hdr _iph;
 117                 uint8_t nexthdr;
 118                 __be16 frag_off;
 119                 int offset_ph;
 120
 121                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
 122                 if (ih == NULL) {
 123                         pr_cont(" INCOMPLETE IPv6 header");
 124                         goto out;
 125                 }
 126                 pr_cont(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
 127                         &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
 128                 nexthdr = ih->nexthdr;
 129                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
 130                 if (offset_ph == -1)
 131                         goto out;
 132                 print_ports(skb, nexthdr, offset_ph);
 133                 goto out;
 134         }
 135 #endif
 136
 137         if ((bitmask & EBT_LOG_ARP) &&
 138             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 139              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 140                 const struct arphdr *ah;
 141                 struct arphdr _arph;
 142
 143                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 144                 if (ah == NULL) {
 145                         pr_cont(" INCOMPLETE ARP header");
 146                         goto out;
 147                 }
 148                 pr_cont(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 149                         ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 150                         ntohs(ah->ar_op));
 151
 152                 /* If it's for Ethernet and the lengths are OK,
 153                  * then log the ARP payload
 154                  */
 155                 if (ah->ar_hrd == htons(1) &&
 156                     ah->ar_hln == ETH_ALEN &&
 157                     ah->ar_pln == sizeof(__be32)) {
 158                         const struct arppayload *ap;
 159                         struct arppayload _arpp;
 160
 161                         ap = skb_header_pointer(skb, sizeof(_arph),
 162                                                 sizeof(_arpp), &_arpp);
 163                         if (ap == NULL) {
 164                                 pr_cont(" INCOMPLETE ARP payload");
 165                                 goto out;
 166                         }
 167                         pr_cont(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
 168                                 ap->mac_src, ap->ip_src,
 169                                 ap->mac_dst, ap->ip_dst);
 170                 }
 171         }
 172 out:
 173         pr_cont("\n");
 174         spin_unlock_bh(&ebt_log_lock);
 175 }
 176
 177 static unsigned int
 178 ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 179 {
 180         const struct ebt_log_info *info = par->targinfo;
 181         struct nf_loginfo li;
 182         struct net *net = xt_net(par);
 183
 184         li.type = NF_LOG_TYPE_LOG;
 185         li.u.log.level = info->loglevel;
 186         li.u.log.logflags = info->bitmask;
 187
 188         /* Remember that we have to use ebt_log_packet() not to break backward
 189          * compatibility. We cannot use the default bridge packet logger via
 190          * nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
 191          */
 192         if (info->bitmask & EBT_LOG_NFLOG)
 193                 nf_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
 194                               xt_in(par), xt_out(par), &li, "%s",
 195                               info->prefix);
 196         else
 197                 ebt_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
 198                                xt_in(par), xt_out(par), &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");