linux/net/bridge/netfilter/ebt_log.c
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   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
  25static DEFINE_SPINLOCK(ebt_log_lock);
  26
  27static 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
  39struct tcpudphdr
  40{
  41        __be16 src;
  42        __be16 dst;
  43};
  44
  45struct 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
  53static void
  54print_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
  74static void
  75ebt_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        }
 172out:
 173        printk("\n");
 174        spin_unlock_bh(&ebt_log_lock);
 175
 176}
 177
 178static unsigned int
 179ebt_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
 202static 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
 212static int __init ebt_log_init(void)
 213{
 214        return xt_register_target(&ebt_log_tg_reg);
 215}
 216
 217static void __exit ebt_log_fini(void)
 218{
 219        xt_unregister_target(&ebt_log_tg_reg);
 220}
 221
 222module_init(ebt_log_init);
 223module_exit(ebt_log_fini);
 224MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
 225MODULE_LICENSE("GPL");
 226