net/mptcp/ctrl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Multipath TCP
   3  *
   4  * Copyright (c) 2019, Tessares SA.
   5  */
   6
   7 #include <linux/sysctl.h>
   8
   9 #include <net/net_namespace.h>
  10 #include <net/netns/generic.h>
  11
  12 #include "protocol.h"
  13
  14 #define MPTCP_SYSCTL_PATH "net/mptcp"
  15
  16 static int mptcp_pernet_id;
  17 struct mptcp_pernet {
  18         struct ctl_table_header *ctl_table_hdr;
  19
  20         int mptcp_enabled;
  21 };
  22
  23 static struct mptcp_pernet *mptcp_get_pernet(struct net *net)
  24 {
  25         return net_generic(net, mptcp_pernet_id);
  26 }
  27
  28 int mptcp_is_enabled(struct net *net)
  29 {
  30         return mptcp_get_pernet(net)->mptcp_enabled;
  31 }
  32
  33 static struct ctl_table mptcp_sysctl_table[] = {
  34         {
  35                 .procname = "enabled",
  36                 .maxlen = sizeof(int),
  37                 .mode = 0644,
  38                 /* users with CAP_NET_ADMIN or root (not and) can change this
  39                  * value, same as other sysctl or the 'net' tree.
  40                  */
  41                 .proc_handler = proc_dointvec,
  42         },
  43         {}
  44 };
  45
  46 static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
  47 {
  48         pernet->mptcp_enabled = 1;
  49 }
  50
  51 static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
  52 {
  53         struct ctl_table_header *hdr;
  54         struct ctl_table *table;
  55
  56         table = mptcp_sysctl_table;
  57         if (!net_eq(net, &init_net)) {
  58                 table = kmemdup(table, sizeof(mptcp_sysctl_table), GFP_KERNEL);
  59                 if (!table)
  60                         goto err_alloc;
  61         }
  62
  63         table[0].data = &pernet->mptcp_enabled;
  64
  65         hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table);
  66         if (!hdr)
  67                 goto err_reg;
  68
  69         pernet->ctl_table_hdr = hdr;
  70
  71         return 0;
  72
  73 err_reg:
  74         if (!net_eq(net, &init_net))
  75                 kfree(table);
  76 err_alloc:
  77         return -ENOMEM;
  78 }
  79
  80 static void mptcp_pernet_del_table(struct mptcp_pernet *pernet)
  81 {
  82         struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg;
  83
  84         unregister_net_sysctl_table(pernet->ctl_table_hdr);
  85
  86         kfree(table);
  87 }
  88
  89 static int __net_init mptcp_net_init(struct net *net)
  90 {
  91         struct mptcp_pernet *pernet = mptcp_get_pernet(net);
  92
  93         mptcp_pernet_set_defaults(pernet);
  94
  95         return mptcp_pernet_new_table(net, pernet);
  96 }
  97
  98 /* Note: the callback will only be called per extra netns */
  99 static void __net_exit mptcp_net_exit(struct net *net)
 100 {
 101         struct mptcp_pernet *pernet = mptcp_get_pernet(net);
 102
 103         mptcp_pernet_del_table(pernet);
 104 }
 105
 106 static struct pernet_operations mptcp_pernet_ops = {
 107         .init = mptcp_net_init,
 108         .exit = mptcp_net_exit,
 109         .id = &mptcp_pernet_id,
 110         .size = sizeof(struct mptcp_pernet),
 111 };
 112
 113 void __init mptcp_init(void)
 114 {
 115         mptcp_proto_init();
 116
 117         if (register_pernet_subsys(&mptcp_pernet_ops) < 0)
 118                 panic("Failed to register MPTCP pernet subsystem.\n");
 119 }
 120
 121 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 122 int __init mptcpv6_init(void)
 123 {
 124         int err;
 125
 126         err = mptcp_proto_v6_init();
 127
 128         return err;
 129 }
 130 #endif