net/netfilter/nft_log.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  * Copyright (c) 2012-2014 Pablo Neira Ayuso <pablo@netfilter.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/netlink.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_tables.h>
  19 #include <net/netfilter/nf_log.h>
  20 #include <linux/netdevice.h>
  21
  22 static const char *nft_log_null_prefix = "";
  23
  24 struct nft_log {
  25         struct nf_loginfo       loginfo;
  26         char                    *prefix;
  27 };
  28
  29 static void nft_log_eval(const struct nft_expr *expr,
  30                          struct nft_regs *regs,
  31                          const struct nft_pktinfo *pkt)
  32 {
  33         const struct nft_log *priv = nft_expr_priv(expr);
  34
  35         nf_log_packet(pkt->net, pkt->pf, pkt->hook, 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         [NFTA_LOG_LEVEL]        = { .type = NLA_U32 },
  45         [NFTA_LOG_FLAGS]        = { .type = NLA_U32 },
  46 };
  47
  48 static int nft_log_init(const struct nft_ctx *ctx,
  49                         const struct nft_expr *expr,
  50                         const struct nlattr * const tb[])
  51 {
  52         struct nft_log *priv = nft_expr_priv(expr);
  53         struct nf_loginfo *li = &priv->loginfo;
  54         const struct nlattr *nla;
  55         int err;
  56
  57         li->type = NF_LOG_TYPE_LOG;
  58         if (tb[NFTA_LOG_LEVEL] != NULL &&
  59             tb[NFTA_LOG_GROUP] != NULL)
  60                 return -EINVAL;
  61         if (tb[NFTA_LOG_GROUP] != NULL)
  62                 li->type = NF_LOG_TYPE_ULOG;
  63
  64         nla = tb[NFTA_LOG_PREFIX];
  65         if (nla != NULL) {
  66                 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
  67                 if (priv->prefix == NULL)
  68                         return -ENOMEM;
  69                 nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
  70         } else {
  71                 priv->prefix = (char *)nft_log_null_prefix;
  72         }
  73
  74         switch (li->type) {
  75         case NF_LOG_TYPE_LOG:
  76                 if (tb[NFTA_LOG_LEVEL] != NULL) {
  77                         li->u.log.level =
  78                                 ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
  79                 } else {
  80                         li->u.log.level = LOGLEVEL_WARNING;
  81                 }
  82                 if (li->u.log.level > LOGLEVEL_DEBUG) {
  83                         err = -EINVAL;
  84                         goto err1;
  85                 }
  86
  87                 if (tb[NFTA_LOG_FLAGS] != NULL) {
  88                         li->u.log.logflags =
  89                                 ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
  90                 }
  91                 break;
  92         case NF_LOG_TYPE_ULOG:
  93                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
  94                 if (tb[NFTA_LOG_SNAPLEN] != NULL) {
  95                         li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
  96                         li->u.ulog.copy_len =
  97                                 ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
  98                 }
  99                 if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
 100                         li->u.ulog.qthreshold =
 101                                 ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
 102                 }
 103                 break;
 104         }
 105
 106         err = nf_logger_find_get(ctx->afi->family, li->type);
 107         if (err < 0)
 108                 goto err1;
 109
 110         return 0;
 111
 112 err1:
 113         if (priv->prefix != nft_log_null_prefix)
 114                 kfree(priv->prefix);
 115         return err;
 116 }
 117
 118 static void nft_log_destroy(const struct nft_ctx *ctx,
 119                             const struct nft_expr *expr)
 120 {
 121         struct nft_log *priv = nft_expr_priv(expr);
 122         struct nf_loginfo *li = &priv->loginfo;
 123
 124         if (priv->prefix != nft_log_null_prefix)
 125                 kfree(priv->prefix);
 126
 127         nf_logger_put(ctx->afi->family, li->type);
 128 }
 129
 130 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
 131 {
 132         const struct nft_log *priv = nft_expr_priv(expr);
 133         const struct nf_loginfo *li = &priv->loginfo;
 134
 135         if (priv->prefix != nft_log_null_prefix)
 136                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
 137                         goto nla_put_failure;
 138         switch (li->type) {
 139         case NF_LOG_TYPE_LOG:
 140                 if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
 141                         goto nla_put_failure;
 142
 143                 if (li->u.log.logflags) {
 144                         if (nla_put_be32(skb, NFTA_LOG_FLAGS,
 145                                          htonl(li->u.log.logflags)))
 146                                 goto nla_put_failure;
 147                 }
 148                 break;
 149         case NF_LOG_TYPE_ULOG:
 150                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
 151                         goto nla_put_failure;
 152
 153                 if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
 154                         if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
 155                                          htonl(li->u.ulog.copy_len)))
 156                                 goto nla_put_failure;
 157                 }
 158                 if (li->u.ulog.qthreshold) {
 159                         if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 160                                          htons(li->u.ulog.qthreshold)))
 161                                 goto nla_put_failure;
 162                 }
 163                 break;
 164         }
 165         return 0;
 166
 167 nla_put_failure:
 168         return -1;
 169 }
 170
 171 static struct nft_expr_type nft_log_type;
 172 static const struct nft_expr_ops nft_log_ops = {
 173         .type           = &nft_log_type,
 174         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 175         .eval           = nft_log_eval,
 176         .init           = nft_log_init,
 177         .destroy        = nft_log_destroy,
 178         .dump           = nft_log_dump,
 179 };
 180
 181 static struct nft_expr_type nft_log_type __read_mostly = {
 182         .name           = "log",
 183         .ops            = &nft_log_ops,
 184         .policy         = nft_log_policy,
 185         .maxattr        = NFTA_LOG_MAX,
 186         .owner          = THIS_MODULE,
 187 };
 188
 189 static int __init nft_log_module_init(void)
 190 {
 191         return nft_register_expr(&nft_log_type);
 192 }
 193
 194 static void __exit nft_log_module_exit(void)
 195 {
 196         nft_unregister_expr(&nft_log_type);
 197 }
 198
 199 module_init(nft_log_module_init);
 200 module_exit(nft_log_module_exit);
 201
 202 MODULE_LICENSE("GPL");
 203 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 204 MODULE_ALIAS_NFT_EXPR("log");