1 /* -*- linux-c -*- 2 * sysctl_net.c: sysctl interface to net subsystem. 3 * 4 * Begun April 1, 1996, Mike Shaver. 5 * Added /proc/sys/net directories for each protocol family. [MS] 6 * 7 * Revision 1.2 1996/05/08 20:24:40 shaver 8 * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and 9 * NET_IPV4_IP_FORWARD. 10 * 11 * 12 */ 13 14 #include <linux/mm.h> 15 #include <linux/export.h> 16 #include <linux/sysctl.h> 17 #include <linux/nsproxy.h> 18 19 #include <net/sock.h> 20 21 #ifdef CONFIG_INET 22 #include <net/ip.h> 23 #endif 24 25 #ifdef CONFIG_NET 26 #include <linux/if_ether.h> 27 #endif 28 29 static struct ctl_table_set * 30 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces) 31 { 32 return &namespaces->net_ns->sysctls; 33 } 34 35 static int is_seen(struct ctl_table_set *set) 36 { 37 return ¤t->nsproxy->net_ns->sysctls == set; 38 } 39 40 /* Return standard mode bits for table entry. */ 41 static int net_ctl_permissions(struct ctl_table_root *root, 42 struct nsproxy *nsproxy, 43 struct ctl_table *table) 44 { 45 /* Allow network administrator to have same access as root. */ 46 if (capable(CAP_NET_ADMIN)) { 47 int mode = (table->mode >> 6) & 7; 48 return (mode << 6) | (mode << 3) | mode; 49 } 50 return table->mode; 51 } 52 53 static struct ctl_table_root net_sysctl_root = { 54 .lookup = net_ctl_header_lookup, 55 .permissions = net_ctl_permissions, 56 }; 57 58 static int __net_init sysctl_net_init(struct net *net) 59 { 60 setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen); 61 return 0; 62 } 63 64 static void __net_exit sysctl_net_exit(struct net *net) 65 { 66 retire_sysctl_set(&net->sysctls); 67 } 68 69 static struct pernet_operations sysctl_pernet_ops = { 70 .init = sysctl_net_init, 71 .exit = sysctl_net_exit, 72 }; 73 74 static struct ctl_table_header *net_header; 75 __init int net_sysctl_init(void) 76 { 77 static struct ctl_table empty[1]; 78 int ret = -ENOMEM; 79 /* Avoid limitations in the sysctl implementation by 80 * registering "/proc/sys/net" as an empty directory not in a 81 * network namespace. 82 */ 83 net_header = register_sysctl("net", empty); 84 if (!net_header) 85 goto out; 86 ret = register_pernet_subsys(&sysctl_pernet_ops); 87 if (ret) 88 goto out; 89 register_sysctl_root(&net_sysctl_root); 90 out: 91 return ret; 92 } 93 94 struct ctl_table_header *register_net_sysctl(struct net *net, 95 const char *path, struct ctl_table *table) 96 { 97 return __register_sysctl_table(&net->sysctls, path, table); 98 } 99 EXPORT_SYMBOL_GPL(register_net_sysctl); 100 101 void unregister_net_sysctl_table(struct ctl_table_header *header) 102 { 103 unregister_sysctl_table(header); 104 } 105 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table); 106