linux/net/bridge/netfilter/ebt_log.c
<<
>>
Prefs
   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        __be16 src;
  41        __be16 dst;
  42};
  43
  44struct 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
  51static void
  52print_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
  72static void
  73ebt_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        }
 172out:
 173        pr_cont("\n");
 174        spin_unlock_bh(&ebt_log_lock);
 175}
 176
 177static unsigned int
 178ebt_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
 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