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_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, pkt->ops->pf, 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         [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 ret;
  57
  58         nla = tb[NFTA_LOG_PREFIX];
  59         if (nla != NULL) {
  60                 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
  61                 if (priv->prefix == NULL)
  62                         return -ENOMEM;
  63                 nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
  64         } else {
  65                 priv->prefix = (char *)nft_log_null_prefix;
  66         }
  67
  68         li->type = NF_LOG_TYPE_LOG;
  69         if (tb[NFTA_LOG_LEVEL] != NULL &&
  70             tb[NFTA_LOG_GROUP] != NULL)
  71                 return -EINVAL;
  72         if (tb[NFTA_LOG_GROUP] != NULL)
  73                 li->type = NF_LOG_TYPE_ULOG;
  74
  75         switch (li->type) {
  76         case NF_LOG_TYPE_LOG:
  77                 if (tb[NFTA_LOG_LEVEL] != NULL) {
  78                         li->u.log.level =
  79                                 ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
  80                 } else {
  81                         li->u.log.level = 4;
  82                 }
  83                 if (tb[NFTA_LOG_FLAGS] != NULL) {
  84                         li->u.log.logflags =
  85                                 ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
  86                 }
  87                 break;
  88         case NF_LOG_TYPE_ULOG:
  89                 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
  90                 if (tb[NFTA_LOG_SNAPLEN] != NULL) {
  91                         li->u.ulog.copy_len =
  92                                 ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
  93                 }
  94                 if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
  95                         li->u.ulog.qthreshold =
  96                                 ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
  97                 }
  98                 break;
  99         }
 100
 101         if (ctx->afi->family == NFPROTO_INET) {
 102                 ret = nf_logger_find_get(NFPROTO_IPV4, li->type);
 103                 if (ret < 0)
 104                         return ret;
 105
 106                 ret = nf_logger_find_get(NFPROTO_IPV6, li->type);
 107                 if (ret < 0) {
 108                         nf_logger_put(NFPROTO_IPV4, li->type);
 109                         return ret;
 110                 }
 111                 return 0;
 112         }
 113
 114         return nf_logger_find_get(ctx->afi->family, li->type);
 115 }
 116
 117 static void nft_log_destroy(const struct nft_ctx *ctx,
 118                             const struct nft_expr *expr)
 119 {
 120         struct nft_log *priv = nft_expr_priv(expr);
 121         struct nf_loginfo *li = &priv->loginfo;
 122
 123         if (priv->prefix != nft_log_null_prefix)
 124                 kfree(priv->prefix);
 125
 126         if (ctx->afi->family == NFPROTO_INET) {
 127                 nf_logger_put(NFPROTO_IPV4, li->type);
 128                 nf_logger_put(NFPROTO_IPV6, li->type);
 129         } else {
 130                 nf_logger_put(ctx->afi->family, li->type);
 131         }
 132 }
 133
 134 static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
 135 {
 136         const struct nft_log *priv = nft_expr_priv(expr);
 137         const struct nf_loginfo *li = &priv->loginfo;
 138
 139         if (priv->prefix != nft_log_null_prefix)
 140                 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
 141                         goto nla_put_failure;
 142         switch (li->type) {
 143         case NF_LOG_TYPE_LOG:
 144                 if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
 145                         goto nla_put_failure;
 146
 147                 if (li->u.log.logflags) {
 148                         if (nla_put_be32(skb, NFTA_LOG_FLAGS,
 149                                          htonl(li->u.log.logflags)))
 150                                 goto nla_put_failure;
 151                 }
 152                 break;
 153         case NF_LOG_TYPE_ULOG:
 154                 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
 155                         goto nla_put_failure;
 156
 157                 if (li->u.ulog.copy_len) {
 158                         if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
 159                                          htonl(li->u.ulog.copy_len)))
 160                                 goto nla_put_failure;
 161                 }
 162                 if (li->u.ulog.qthreshold) {
 163                         if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
 164                                          htons(li->u.ulog.qthreshold)))
 165                                 goto nla_put_failure;
 166                 }
 167                 break;
 168         }
 169         return 0;
 170
 171 nla_put_failure:
 172         return -1;
 173 }
 174
 175 static struct nft_expr_type nft_log_type;
 176 static const struct nft_expr_ops nft_log_ops = {
 177         .type           = &nft_log_type,
 178         .size           = NFT_EXPR_SIZE(sizeof(struct nft_log)),
 179         .eval           = nft_log_eval,
 180         .init           = nft_log_init,
 181         .destroy        = nft_log_destroy,
 182         .dump           = nft_log_dump,
 183 };
 184
 185 static struct nft_expr_type nft_log_type __read_mostly = {
 186         .name           = "log",
 187         .ops            = &nft_log_ops,
 188         .policy         = nft_log_policy,
 189         .maxattr        = NFTA_LOG_MAX,
 190         .owner          = THIS_MODULE,
 191 };
 192
 193 static int __init nft_log_module_init(void)
 194 {
 195         return nft_register_expr(&nft_log_type);
 196 }
 197
 198 static void __exit nft_log_module_exit(void)
 199 {
 200         nft_unregister_expr(&nft_log_type);
 201 }
 202
 203 module_init(nft_log_module_init);
 204 module_exit(nft_log_module_exit);
 205
 206 MODULE_LICENSE("GPL");
 207 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 208 MODULE_ALIAS_NFT_EXPR("log");