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 ret;
  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
  67         li->type = NF_LOG_TYPE_LOG;
  68         if (tb[NFTA_LOG_LEVEL] != NULL &&
  69             tb[NFTA_LOG_GROUP] != NULL)
  70                 return -EINVAL;
  71         if (tb[NFTA_LOG_GROUP] != NULL)
  72                 li->type = NF_LOG_TYPE_ULOG;
  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 (tb[NFTA_LOG_FLAGS] != NULL) {
  83                         li->u.log.logflags =
  84                                 ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
  85                 }
  86                 break;
  87         case NF_LOG_TYPE_ULOG:
  88                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
  89                 if (tb[NFTA_LOG_SNAPLEN] != NULL) {
  90                         li->u.ulog.copy_len =
  91                                 ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
  92                 }
  93                 if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
  94                         li->u.ulog.qthreshold =
  95                                 ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
  96                 }
  97                 break;
  98         }
  99
 100         if (ctx->afi->family == NFPROTO_INET) {
 101                 ret = nf_logger_find_get(NFPROTO_IPV4, li->type);
 102                 if (ret < 0)
 103                         return ret;
 104
 105                 ret = nf_logger_find_get(NFPROTO_IPV6, li->type);
 106                 if (ret < 0) {
 107                         nf_logger_put(NFPROTO_IPV4, li->type);
 108                         return ret;
 109                 }
 110                 return 0;
 111         }
 112
 113         return nf_logger_find_get(ctx->afi->family, li->type);
 114 }
 115
 116 static void nft_log_destroy(const struct nft_ctx *ctx,
 117                             const struct nft_expr *expr)
 118 {
 119         struct nft_log *priv = nft_expr_priv(expr);
 120         struct nf_loginfo *li = &priv->loginfo;
 121
 122         if (priv->prefix != nft_log_null_prefix)
 123                 kfree(priv->prefix);
 124
 125         if (ctx->afi->family == NFPROTO_INET) {
 126                 nf_logger_put(NFPROTO_IPV4, li->type);
 127                 nf_logger_put(NFPROTO_IPV6, li->type);
 128         } else {
 129                 nf_logger_put(ctx->afi->family, li->type);
 130         }
 131 }
 132
 133 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
 134 {
 135         const struct nft_log *priv = nft_expr_priv(expr);
 136         const struct nf_loginfo *li = &priv->loginfo;
 137
 138         if (priv->prefix != nft_log_null_prefix)
 139                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
 140                         goto nla_put_failure;
 141         switch (li->type) {
 142         case NF_LOG_TYPE_LOG:
 143                 if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
 144                         goto nla_put_failure;
 145
 146                 if (li->u.log.logflags) {
 147                         if (nla_put_be32(skb, NFTA_LOG_FLAGS,
 148                                          htonl(li->u.log.logflags)))
 149                                 goto nla_put_failure;
 150                 }
 151                 break;
 152         case NF_LOG_TYPE_ULOG:
 153                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
 154                         goto nla_put_failure;
 155
 156                 if (li->u.ulog.copy_len) {
 157                         if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
 158                                          htonl(li->u.ulog.copy_len)))
 159                                 goto nla_put_failure;
 160                 }
 161                 if (li->u.ulog.qthreshold) {
 162                         if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 163                                          htons(li->u.ulog.qthreshold)))
 164                                 goto nla_put_failure;
 165                 }
 166                 break;
 167         }
 168         return 0;
 169
 170 nla_put_failure:
 171         return -1;
 172 }
 173
 174 static struct nft_expr_type nft_log_type;
 175 static const struct nft_expr_ops nft_log_ops = {
 176         .type           = &nft_log_type,
 177         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 178         .eval           = nft_log_eval,
 179         .init           = nft_log_init,
 180         .destroy        = nft_log_destroy,
 181         .dump           = nft_log_dump,
 182 };
 183
 184 static struct nft_expr_type nft_log_type __read_mostly = {
 185         .name           = "log",
 186         .ops            = &nft_log_ops,
 187         .policy         = nft_log_policy,
 188         .maxattr        = NFTA_LOG_MAX,
 189         .owner          = THIS_MODULE,
 190 };
 191
 192 static int __init nft_log_module_init(void)
 193 {
 194         return nft_register_expr(&nft_log_type);
 195 }
 196
 197 static void __exit nft_log_module_exit(void)
 198 {
 199         nft_unregister_expr(&nft_log_type);
 200 }
 201
 202 module_init(nft_log_module_init);
 203 module_exit(nft_log_module_exit);
 204
 205 MODULE_LICENSE("GPL");
 206 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 207 MODULE_ALIAS_NFT_EXPR("log");