net/netfilter/nft_log.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nf_tables.h>
  17 #include <net/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_log.h>
  19 #include <linux/netdevice.h>
  20
  21 static const char *nft_log_null_prefix = "";
  22
  23 struct nft_log {
  24         struct nf_loginfo       loginfo;
  25         char                    *prefix;
  26 };
  27
  28 static void nft_log_eval(const struct nft_expr *expr,
  29                          struct nft_data data[NFT_REG_MAX + 1],
  30                          const struct nft_pktinfo *pkt)
  31 {
  32         const struct nft_log *priv = nft_expr_priv(expr);
  33         struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
  34
  35         nf_log_packet(net, pkt->ops->pf, pkt->ops->hooknum, pkt->skb, pkt->in,
  36                       pkt->out, &priv->loginfo, "%s", priv->prefix);
  37 }
  38
  39 static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
  40         [NFTA_LOG_GROUP]        = { .type = NLA_U16 },
  41         [NFTA_LOG_PREFIX]       = { .type = NLA_STRING },
  42         [NFTA_LOG_SNAPLEN]      = { .type = NLA_U32 },
  43         [NFTA_LOG_QTHRESHOLD]   = { .type = NLA_U16 },
  44 };
  45
  46 static int nft_log_init(const struct nft_ctx *ctx,
  47                         const struct nft_expr *expr,
  48                         const struct nlattr * const tb[])
  49 {
  50         struct nft_log *priv = nft_expr_priv(expr);
  51         struct nf_loginfo *li = &priv->loginfo;
  52         const struct nlattr *nla;
  53
  54         nla = tb[NFTA_LOG_PREFIX];
  55         if (nla != NULL) {
  56                 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
  57                 if (priv->prefix == NULL)
  58                         return -ENOMEM;
  59                 nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
  60         } else
  61                 priv->prefix = (char *)nft_log_null_prefix;
  62
  63         li->type = NF_LOG_TYPE_ULOG;
  64         if (tb[NFTA_LOG_GROUP] != NULL)
  65                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
  66
  67         if (tb[NFTA_LOG_SNAPLEN] != NULL)
  68                 li->u.ulog.copy_len = ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
  69         if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
  70                 li->u.ulog.qthreshold =
  71                         ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
  72         }
  73
  74         return 0;
  75 }
  76
  77 static void nft_log_destroy(const struct nft_expr *expr)
  78 {
  79         struct nft_log *priv = nft_expr_priv(expr);
  80
  81         if (priv->prefix != nft_log_null_prefix)
  82                 kfree(priv->prefix);
  83 }
  84
  85 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
  86 {
  87         const struct nft_log *priv = nft_expr_priv(expr);
  88         const struct nf_loginfo *li = &priv->loginfo;
  89
  90         if (priv->prefix != nft_log_null_prefix)
  91                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
  92                         goto nla_put_failure;
  93         if (li->u.ulog.group)
  94                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
  95                         goto nla_put_failure;
  96         if (li->u.ulog.copy_len)
  97                 if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
  98                                  htonl(li->u.ulog.copy_len)))
  99                         goto nla_put_failure;
 100         if (li->u.ulog.qthreshold)
 101                 if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 102                                  htons(li->u.ulog.qthreshold)))
 103                         goto nla_put_failure;
 104         return 0;
 105
 106 nla_put_failure:
 107         return -1;
 108 }
 109
 110 static struct nft_expr_type nft_log_type;
 111 static const struct nft_expr_ops nft_log_ops = {
 112         .type           = &nft_log_type,
 113         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 114         .eval           = nft_log_eval,
 115         .init           = nft_log_init,
 116         .destroy        = nft_log_destroy,
 117         .dump           = nft_log_dump,
 118 };
 119
 120 static struct nft_expr_type nft_log_type __read_mostly = {
 121         .name           = "log",
 122         .ops            = &nft_log_ops,
 123         .policy         = nft_log_policy,
 124         .maxattr        = NFTA_LOG_MAX,
 125         .owner          = THIS_MODULE,
 126 };
 127
 128 static int __init nft_log_module_init(void)
 129 {
 130         return nft_register_expr(&nft_log_type);
 131 }
 132
 133 static void __exit nft_log_module_exit(void)
 134 {
 135         nft_unregister_expr(&nft_log_type);
 136 }
 137
 138 module_init(nft_log_module_init);
 139 module_exit(nft_log_module_exit);
 140
 141 MODULE_LICENSE("GPL");
 142 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 143 MODULE_ALIAS_NFT_EXPR("log");