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         int                     family;
  27 };
  28
  29 static void nft_log_eval(const struct nft_expr *expr,
  30                          struct nft_data data[NFT_REG_MAX + 1],
  31                          const struct nft_pktinfo *pkt)
  32 {
  33         const struct nft_log *priv = nft_expr_priv(expr);
  34         struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
  35
  36         nf_log_packet(net, priv->family, pkt->ops->hooknum, pkt->skb, pkt->in,
  37                       pkt->out, &priv->loginfo, "%s", priv->prefix);
  38 }
  39
  40 static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
  41         [NFTA_LOG_GROUP]        = { .type = NLA_U16 },
  42         [NFTA_LOG_PREFIX]       = { .type = NLA_STRING },
  43         [NFTA_LOG_SNAPLEN]      = { .type = NLA_U32 },
  44         [NFTA_LOG_QTHRESHOLD]   = { .type = NLA_U16 },
  45 };
  46
  47 static int nft_log_init(const struct nft_ctx *ctx,
  48                         const struct nft_expr *expr,
  49                         const struct nlattr * const tb[])
  50 {
  51         struct nft_log *priv = nft_expr_priv(expr);
  52         struct nf_loginfo *li = &priv->loginfo;
  53         const struct nlattr *nla;
  54
  55         priv->family = ctx->afi->family;
  56
  57         nla = tb[NFTA_LOG_PREFIX];
  58         if (nla != NULL) {
  59                 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
  60                 if (priv->prefix == NULL)
  61                         return -ENOMEM;
  62                 nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
  63         } else
  64                 priv->prefix = (char *)nft_log_null_prefix;
  65
  66         li->type = NF_LOG_TYPE_ULOG;
  67         if (tb[NFTA_LOG_GROUP] != NULL)
  68                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
  69
  70         if (tb[NFTA_LOG_SNAPLEN] != NULL)
  71                 li->u.ulog.copy_len = ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
  72         if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
  73                 li->u.ulog.qthreshold =
  74                         ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
  75         }
  76
  77         return 0;
  78 }
  79
  80 static void nft_log_destroy(const struct nft_expr *expr)
  81 {
  82         struct nft_log *priv = nft_expr_priv(expr);
  83
  84         if (priv->prefix != nft_log_null_prefix)
  85                 kfree(priv->prefix);
  86 }
  87
  88 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
  89 {
  90         const struct nft_log *priv = nft_expr_priv(expr);
  91         const struct nf_loginfo *li = &priv->loginfo;
  92
  93         if (priv->prefix != nft_log_null_prefix)
  94                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
  95                         goto nla_put_failure;
  96         if (li->u.ulog.group)
  97                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
  98                         goto nla_put_failure;
  99         if (li->u.ulog.copy_len)
 100                 if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
 101                                  htonl(li->u.ulog.copy_len)))
 102                         goto nla_put_failure;
 103         if (li->u.ulog.qthreshold)
 104                 if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 105                                  htons(li->u.ulog.qthreshold)))
 106                         goto nla_put_failure;
 107         return 0;
 108
 109 nla_put_failure:
 110         return -1;
 111 }
 112
 113 static struct nft_expr_type nft_log_type;
 114 static const struct nft_expr_ops nft_log_ops = {
 115         .type           = &nft_log_type,
 116         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 117         .eval           = nft_log_eval,
 118         .init           = nft_log_init,
 119         .destroy        = nft_log_destroy,
 120         .dump           = nft_log_dump,
 121 };
 122
 123 static struct nft_expr_type nft_log_type __read_mostly = {
 124         .name           = "log",
 125         .ops            = &nft_log_ops,
 126         .policy         = nft_log_policy,
 127         .maxattr        = NFTA_LOG_MAX,
 128         .owner          = THIS_MODULE,
 129 };
 130
 131 static int __init nft_log_module_init(void)
 132 {
 133         return nft_register_expr(&nft_log_type);
 134 }
 135
 136 static void __exit nft_log_module_exit(void)
 137 {
 138         nft_unregister_expr(&nft_log_type);
 139 }
 140
 141 module_init(nft_log_module_init);
 142 module_exit(nft_log_module_exit);
 143
 144 MODULE_LICENSE("GPL");
 145 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 146 MODULE_ALIAS_NFT_EXPR("log");