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