+#ifdef CONFIG_SYSCTL
+static int zero;
+
+static struct ctl_table ip4_frags_ctl_table[] = {
+ {
+ .ctl_name = NET_IPV4_IPFRAG_HIGH_THRESH,
+ .procname = "ipfrag_high_thresh",
+ .data = &init_net.ipv4.frags.high_thresh,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec
+ },
+ {
+ .ctl_name = NET_IPV4_IPFRAG_LOW_THRESH,
+ .procname = "ipfrag_low_thresh",
+ .data = &init_net.ipv4.frags.low_thresh,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec
+ },
+ {
+ .ctl_name = NET_IPV4_IPFRAG_TIME,
+ .procname = "ipfrag_time",
+ .data = &init_net.ipv4.frags.timeout,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_jiffies,
+ .strategy = &sysctl_jiffies
+ },
+ {
+ .ctl_name = NET_IPV4_IPFRAG_SECRET_INTERVAL,
+ .procname = "ipfrag_secret_interval",
+ .data = &ip4_frags.secret_interval,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_jiffies,
+ .strategy = &sysctl_jiffies
+ },
+ {
+ .procname = "ipfrag_max_dist",
+ .data = &sysctl_ipfrag_max_dist,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &zero
+ },
+ { }
+};
+
+static int ip4_frags_ctl_register(struct net *net)
+{
+ struct ctl_table *table;
+ struct ctl_table_header *hdr;
+
+ table = ip4_frags_ctl_table;
+ if (net != &init_net) {
+ table = kmemdup(table, sizeof(ip4_frags_ctl_table), GFP_KERNEL);
+ if (table == NULL)
+ goto err_alloc;
+
+ table[0].data = &net->ipv4.frags.high_thresh;
+ table[1].data = &net->ipv4.frags.low_thresh;
+ table[2].data = &net->ipv4.frags.timeout;
+ table[3].mode &= ~0222;
+ table[4].mode &= ~0222;
+ }
+
+ hdr = register_net_sysctl_table(net, net_ipv4_ctl_path, table);
+ if (hdr == NULL)
+ goto err_reg;
+
+ net->ipv4.frags_hdr = hdr;
+ return 0;
+
+err_reg:
+ if (net != &init_net)
+ kfree(table);
+err_alloc:
+ return -ENOMEM;
+}
+
+static void ip4_frags_ctl_unregister(struct net *net)
+{
+ struct ctl_table *table;
+
+ table = net->ipv4.frags_hdr->ctl_table_arg;
+ unregister_net_sysctl_table(net->ipv4.frags_hdr);
+ kfree(table);
+}
+#else
+static inline int ip4_frags_ctl_register(struct net *net)
+{
+ return 0;
+}
+
+static inline void ip4_frags_ctl_unregister(struct net *net)
+{
+}
+#endif
+
+static int ipv4_frags_init_net(struct net *net)
+{
+ /*
+ * Fragment cache limits. We will commit 256K at one time. Should we
+ * cross that limit we will prune down to 192K. This should cope with
+ * even the most extreme cases without allowing an attacker to
+ * measurably harm machine performance.
+ */
+ net->ipv4.frags.high_thresh = 256 * 1024;
+ net->ipv4.frags.low_thresh = 192 * 1024;
+ /*
+ * Important NOTE! Fragment queue must be destroyed before MSL expires.
+ * RFC791 is wrong proposing to prolongate timer each fragment arrival
+ * by TTL.
+ */
+ net->ipv4.frags.timeout = IP_FRAG_TIME;
+
+ inet_frags_init_net(&net->ipv4.frags);
+
+ return ip4_frags_ctl_register(net);
+}
+
+static void ipv4_frags_exit_net(struct net *net)
+{
+ ip4_frags_ctl_unregister(net);
+ inet_frags_exit_net(&net->ipv4.frags, &ip4_frags);
+}
+
+static struct pernet_operations ip4_frags_ops = {
+ .init = ipv4_frags_init_net,
+ .exit = ipv4_frags_exit_net,
+};
+