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(nft_net(pkt), nft_pf(pkt), nft_hook(pkt), pkt->skb,
  36                       nft_in(pkt), nft_out(pkt), &priv->loginfo, "%s",
  37                       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                                     .len = NF_LOG_PREFIXLEN - 1 },
  44         [NFTA_LOG_SNAPLEN]      = { .type = NLA_U32 },
  45         [NFTA_LOG_QTHRESHOLD]   = { .type = NLA_U16 },
  46         [NFTA_LOG_LEVEL]        = { .type = NLA_U32 },
  47         [NFTA_LOG_FLAGS]        = { .type = NLA_U32 },
  48 };
  49
  50 static int nft_log_init(const struct nft_ctx *ctx,
  51                         const struct nft_expr *expr,
  52                         const struct nlattr * const tb[])
  53 {
  54         struct nft_log *priv = nft_expr_priv(expr);
  55         struct nf_loginfo *li = &priv->loginfo;
  56         const struct nlattr *nla;
  57         int err;
  58
  59         li->type = NF_LOG_TYPE_LOG;
  60         if (tb[NFTA_LOG_LEVEL] != NULL &&
  61             tb[NFTA_LOG_GROUP] != NULL)
  62                 return -EINVAL;
  63         if (tb[NFTA_LOG_GROUP] != NULL) {
  64                 li->type = NF_LOG_TYPE_ULOG;
  65                 if (tb[NFTA_LOG_FLAGS] != NULL)
  66                         return -EINVAL;
  67         }
  68
  69         nla = tb[NFTA_LOG_PREFIX];
  70         if (nla != NULL) {
  71                 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
  72                 if (priv->prefix == NULL)
  73                         return -ENOMEM;
  74                 nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
  75         } else {
  76                 priv->prefix = (char *)nft_log_null_prefix;
  77         }
  78
  79         switch (li->type) {
  80         case NF_LOG_TYPE_LOG:
  81                 if (tb[NFTA_LOG_LEVEL] != NULL) {
  82                         li->u.log.level =
  83                                 ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
  84                 } else {
  85                         li->u.log.level = LOGLEVEL_WARNING;
  86                 }
  87                 if (li->u.log.level > LOGLEVEL_DEBUG) {
  88                         err = -EINVAL;
  89                         goto err1;
  90                 }
  91
  92                 if (tb[NFTA_LOG_FLAGS] != NULL) {
  93                         li->u.log.logflags =
  94                                 ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
  95                         if (li->u.log.logflags & ~NF_LOG_MASK) {
  96                                 err = -EINVAL;
  97                                 goto err1;
  98                         }
  99                 }
 100                 break;
 101         case NF_LOG_TYPE_ULOG:
 102                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
 103                 if (tb[NFTA_LOG_SNAPLEN] != NULL) {
 104                         li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
 105                         li->u.ulog.copy_len =
 106                                 ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
 107                 }
 108                 if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
 109                         li->u.ulog.qthreshold =
 110                                 ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
 111                 }
 112                 break;
 113         }
 114
 115         err = nf_logger_find_get(ctx->family, li->type);
 116         if (err < 0)
 117                 goto err1;
 118
 119         return 0;
 120
 121 err1:
 122         if (priv->prefix != nft_log_null_prefix)
 123                 kfree(priv->prefix);
 124         return err;
 125 }
 126
 127 static void nft_log_destroy(const struct nft_ctx *ctx,
 128                             const struct nft_expr *expr)
 129 {
 130         struct nft_log *priv = nft_expr_priv(expr);
 131         struct nf_loginfo *li = &priv->loginfo;
 132
 133         if (priv->prefix != nft_log_null_prefix)
 134                 kfree(priv->prefix);
 135
 136         nf_logger_put(ctx->family, li->type);
 137 }
 138
 139 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
 140 {
 141         const struct nft_log *priv = nft_expr_priv(expr);
 142         const struct nf_loginfo *li = &priv->loginfo;
 143
 144         if (priv->prefix != nft_log_null_prefix)
 145                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
 146                         goto nla_put_failure;
 147         switch (li->type) {
 148         case NF_LOG_TYPE_LOG:
 149                 if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
 150                         goto nla_put_failure;
 151
 152                 if (li->u.log.logflags) {
 153                         if (nla_put_be32(skb, NFTA_LOG_FLAGS,
 154                                          htonl(li->u.log.logflags)))
 155                                 goto nla_put_failure;
 156                 }
 157                 break;
 158         case NF_LOG_TYPE_ULOG:
 159                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
 160                         goto nla_put_failure;
 161
 162                 if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
 163                         if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
 164                                          htonl(li->u.ulog.copy_len)))
 165                                 goto nla_put_failure;
 166                 }
 167                 if (li->u.ulog.qthreshold) {
 168                         if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 169                                          htons(li->u.ulog.qthreshold)))
 170                                 goto nla_put_failure;
 171                 }
 172                 break;
 173         }
 174         return 0;
 175
 176 nla_put_failure:
 177         return -1;
 178 }
 179
 180 static struct nft_expr_type nft_log_type;
 181 static const struct nft_expr_ops nft_log_ops = {
 182         .type           = &nft_log_type,
 183         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 184         .eval           = nft_log_eval,
 185         .init           = nft_log_init,
 186         .destroy        = nft_log_destroy,
 187         .dump           = nft_log_dump,
 188 };
 189
 190 static struct nft_expr_type nft_log_type __read_mostly = {
 191         .name           = "log",
 192         .ops            = &nft_log_ops,
 193         .policy         = nft_log_policy,
 194         .maxattr        = NFTA_LOG_MAX,
 195         .owner          = THIS_MODULE,
 196 };
 197
 198 static int __init nft_log_module_init(void)
 199 {
 200         return nft_register_expr(&nft_log_type);
 201 }
 202
 203 static void __exit nft_log_module_exit(void)
 204 {
 205         nft_unregister_expr(&nft_log_type);
 206 }
 207
 208 module_init(nft_log_module_init);
 209 module_exit(nft_log_module_exit);
 210
 211 MODULE_LICENSE("GPL");
 212 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 213 MODULE_ALIAS_NFT_EXPR("log");