diff options
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/Makefile | 5 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 2182 | ||||
| -rw-r--r-- | net/netlink/genetlink.c | 1014 |
3 files changed, 3201 insertions, 0 deletions
diff --git a/net/netlink/Makefile b/net/netlink/Makefile new file mode 100644 index 00000000..bdd6ddf4 --- /dev/null +++ b/net/netlink/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for the netlink driver. +# + +obj-y := af_netlink.o genetlink.o diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c new file mode 100644 index 00000000..59debb73 --- /dev/null +++ b/net/netlink/af_netlink.c @@ -0,0 +1,2182 @@ +/* + * NETLINK Kernel-user communication protocol. + * + * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> + * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith + * added netlink_proto_exit + * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br> + * use nlk_sk, as sk->protinfo is on a diet 8) + * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org> + * - inc module use count of module that owns + * the kernel socket in case userspace opens + * socket of same protocol + * - remove all module support, since netlink is + * mandatory if CONFIG_NET=y these days + */ + +#include <linux/module.h> + +#include <linux/capability.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/stat.h> +#include <linux/socket.h> +#include <linux/un.h> +#include <linux/fcntl.h> +#include <linux/termios.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <asm/uaccess.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/rtnetlink.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/notifier.h> +#include <linux/security.h> +#include <linux/jhash.h> +#include <linux/jiffies.h> +#include <linux/random.h> +#include <linux/bitops.h> +#include <linux/mm.h> +#include <linux/types.h> +#include <linux/audit.h> +#include <linux/mutex.h> + +#include <net/net_namespace.h> +#include <net/sock.h> +#include <net/scm.h> +#include <net/netlink.h> + +#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) +#define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long)) + +struct netlink_sock { + /* struct sock has to be the first member of netlink_sock */ + struct sock sk; + u32 pid; + u32 dst_pid; + u32 dst_group; + u32 flags; + u32 subscriptions; + u32 ngroups; + unsigned long *groups; + unsigned long state; + wait_queue_head_t wait; + struct netlink_callback *cb; + struct mutex *cb_mutex; + struct mutex cb_def_mutex; + void (*netlink_rcv)(struct sk_buff *skb); + struct module *module; +}; + +struct listeners { + struct rcu_head rcu; + unsigned long masks[0]; +}; + +#define NETLINK_KERNEL_SOCKET 0x1 +#define NETLINK_RECV_PKTINFO 0x2 +#define NETLINK_BROADCAST_SEND_ERROR 0x4 +#define NETLINK_RECV_NO_ENOBUFS 0x8 + +static inline struct netlink_sock *nlk_sk(struct sock *sk) +{ + return container_of(sk, struct netlink_sock, sk); +} + +static inline int netlink_is_kernel(struct sock *sk) +{ + return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET; +} + +struct nl_pid_hash { + struct hlist_head *table; + unsigned long rehash_time; + + unsigned int mask; + unsigned int shift; + + unsigned int entries; + unsigned int max_shift; + + u32 rnd; +}; + +struct netlink_table { + struct nl_pid_hash hash; + struct hlist_head mc_list; + struct listeners __rcu *listeners; + unsigned int nl_nonroot; + unsigned int groups; + struct mutex *cb_mutex; + struct module *module; + int registered; +}; + +static struct netlink_table *nl_table; + +static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); + +static int netlink_dump(struct sock *sk); +static void netlink_destroy_callback(struct netlink_callback *cb); + +static DEFINE_RWLOCK(nl_table_lock); +static atomic_t nl_table_users = ATOMIC_INIT(0); + +static ATOMIC_NOTIFIER_HEAD(netlink_chain); + +static inline u32 netlink_group_mask(u32 group) +{ + return group ? 1 << (group - 1) : 0; +} + +static inline struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid) +{ + return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask]; +} + +static void netlink_sock_destruct(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (nlk->cb) { + if (nlk->cb->done) + nlk->cb->done(nlk->cb); + netlink_destroy_callback(nlk->cb); + } + + skb_queue_purge(&sk->sk_receive_queue); + + if (!sock_flag(sk, SOCK_DEAD)) { + printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); + return; + } + + WARN_ON(atomic_read(&sk->sk_rmem_alloc)); + WARN_ON(atomic_read(&sk->sk_wmem_alloc)); + WARN_ON(nlk_sk(sk)->groups); +} + +/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on + * SMP. Look, when several writers sleep and reader wakes them up, all but one + * immediately hit write lock and grab all the cpus. Exclusive sleep solves + * this, _but_ remember, it adds useless work on UP machines. + */ + +void netlink_table_grab(void) + __acquires(nl_table_lock) +{ + might_sleep(); + + write_lock_irq(&nl_table_lock); + + if (atomic_read(&nl_table_users)) { + DECLARE_WAITQUEUE(wait, current); + + add_wait_queue_exclusive(&nl_table_wait, &wait); + for (;;) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (atomic_read(&nl_table_users) == 0) + break; + write_unlock_irq(&nl_table_lock); + schedule(); + write_lock_irq(&nl_table_lock); + } + + __set_current_state(TASK_RUNNING); + remove_wait_queue(&nl_table_wait, &wait); + } +} + +void netlink_table_ungrab(void) + __releases(nl_table_lock) +{ + write_unlock_irq(&nl_table_lock); + wake_up(&nl_table_wait); +} + +static inline void +netlink_lock_table(void) +{ + /* read_lock() synchronizes us to netlink_table_grab */ + + read_lock(&nl_table_lock); + atomic_inc(&nl_table_users); + read_unlock(&nl_table_lock); +} + +static inline void +netlink_unlock_table(void) +{ + if (atomic_dec_and_test(&nl_table_users)) + wake_up(&nl_table_wait); +} + +static struct sock *netlink_lookup(struct net *net, int protocol, u32 pid) +{ + struct nl_pid_hash *hash = &nl_table[protocol].hash; + struct hlist_head *head; + struct sock *sk; + struct hlist_node *node; + + read_lock(&nl_table_lock); + head = nl_pid_hashfn(hash, pid); + sk_for_each(sk, node, head) { + if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) { + sock_hold(sk); + goto found; + } + } + sk = NULL; +found: + read_unlock(&nl_table_lock); + return sk; +} + +static struct hlist_head *nl_pid_hash_zalloc(size_t size) +{ + if (size <= PAGE_SIZE) + return kzalloc(size, GFP_ATOMIC); + else + return (struct hlist_head *) + __get_free_pages(GFP_ATOMIC | __GFP_ZERO, + get_order(size)); +} + +static void nl_pid_hash_free(struct hlist_head *table, size_t size) +{ + if (size <= PAGE_SIZE) + kfree(table); + else + free_pages((unsigned long)table, get_order(size)); +} + +static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow) +{ + unsigned int omask, mask, shift; + size_t osize, size; + struct hlist_head *otable, *table; + int i; + + omask = mask = hash->mask; + osize = size = (mask + 1) * sizeof(*table); + shift = hash->shift; + + if (grow) { + if (++shift > hash->max_shift) + return 0; + mask = mask * 2 + 1; + size *= 2; + } + + table = nl_pid_hash_zalloc(size); + if (!table) + return 0; + + otable = hash->table; + hash->table = table; + hash->mask = mask; + hash->shift = shift; + get_random_bytes(&hash->rnd, sizeof(hash->rnd)); + + for (i = 0; i <= omask; i++) { + struct sock *sk; + struct hlist_node *node, *tmp; + + sk_for_each_safe(sk, node, tmp, &otable[i]) + __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid)); + } + + nl_pid_hash_free(otable, osize); + hash->rehash_time = jiffies + 10 * 60 * HZ; + return 1; +} + +static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len) +{ + int avg = hash->entries >> hash->shift; + + if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1)) + return 1; + + if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) { + nl_pid_hash_rehash(hash, 0); + return 1; + } + + return 0; +} + +static const struct proto_ops netlink_ops; + +static void +netlink_update_listeners(struct sock *sk) +{ + struct netlink_table *tbl = &nl_table[sk->sk_protocol]; + struct hlist_node *node; + unsigned long mask; + unsigned int i; + + for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { + mask = 0; + sk_for_each_bound(sk, node, &tbl->mc_list) { + if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) + mask |= nlk_sk(sk)->groups[i]; + } + tbl->listeners->masks[i] = mask; + } + /* this function is only called with the netlink table "grabbed", which + * makes sure updates are visible before bind or setsockopt return. */ +} + +static int netlink_insert(struct sock *sk, struct net *net, u32 pid) +{ + struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; + struct hlist_head *head; + int err = -EADDRINUSE; + struct sock *osk; + struct hlist_node *node; + int len; + + netlink_table_grab(); + head = nl_pid_hashfn(hash, pid); + len = 0; + sk_for_each(osk, node, head) { + if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid)) + break; + len++; + } + if (node) + goto err; + + err = -EBUSY; + if (nlk_sk(sk)->pid) + goto err; + + err = -ENOMEM; + if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX)) + goto err; + + if (len && nl_pid_hash_dilute(hash, len)) + head = nl_pid_hashfn(hash, pid); + hash->entries++; + nlk_sk(sk)->pid = pid; + sk_add_node(sk, head); + err = 0; + +err: + netlink_table_ungrab(); + return err; +} + +static void netlink_remove(struct sock *sk) +{ + netlink_table_grab(); + if (sk_del_node_init(sk)) + nl_table[sk->sk_protocol].hash.entries--; + if (nlk_sk(sk)->subscriptions) + __sk_del_bind_node(sk); + netlink_table_ungrab(); +} + +static struct proto netlink_proto = { + .name = "NETLINK", + .owner = THIS_MODULE, + .obj_size = sizeof(struct netlink_sock), +}; + +static int __netlink_create(struct net *net, struct socket *sock, + struct mutex *cb_mutex, int protocol) +{ + struct sock *sk; + struct netlink_sock *nlk; + + sock->ops = &netlink_ops; + + sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto); + if (!sk) + return -ENOMEM; + + sock_init_data(sock, sk); + + nlk = nlk_sk(sk); + if (cb_mutex) + nlk->cb_mutex = cb_mutex; + else { + nlk->cb_mutex = &nlk->cb_def_mutex; + mutex_init(nlk->cb_mutex); + } + init_waitqueue_head(&nlk->wait); + + sk->sk_destruct = netlink_sock_destruct; + sk->sk_protocol = protocol; + return 0; +} + +static int netlink_create(struct net *net, struct socket *sock, int protocol, + int kern) +{ + struct module *module = NULL; + struct mutex *cb_mutex; + struct netlink_sock *nlk; + int err = 0; + + sock->state = SS_UNCONNECTED; + + if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) + return -ESOCKTNOSUPPORT; + + if (protocol < 0 || protocol >= MAX_LINKS) + return -EPROTONOSUPPORT; + + netlink_lock_table(); +#ifdef CONFIG_MODULES + if (!nl_table[protocol].registered) { + netlink_unlock_table(); + request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); + netlink_lock_table(); + } +#endif + if (nl_table[protocol].registered && + try_module_get(nl_table[protocol].module)) + module = nl_table[protocol].module; + else + err = -EPROTONOSUPPORT; + cb_mutex = nl_table[protocol].cb_mutex; + netlink_unlock_table(); + + if (err < 0) + goto out; + + err = __netlink_create(net, sock, cb_mutex, protocol); + if (err < 0) + goto out_module; + + local_bh_disable(); + sock_prot_inuse_add(net, &netlink_proto, 1); + local_bh_enable(); + + nlk = nlk_sk(sock->sk); + nlk->module = module; +out: + return err; + +out_module: + module_put(module); + goto out; +} + +static int netlink_release(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk; + + if (!sk) + return 0; + + netlink_remove(sk); + sock_orphan(sk); + nlk = nlk_sk(sk); + + /* + * OK. Socket is unlinked, any packets that arrive now + * will be purged. + */ + + sock->sk = NULL; + wake_up_interruptible_all(&nlk->wait); + + skb_queue_purge(&sk->sk_write_queue); + + if (nlk->pid) { + struct netlink_notify n = { + .net = sock_net(sk), + .protocol = sk->sk_protocol, + .pid = nlk->pid, + }; + atomic_notifier_call_chain(&netlink_chain, + NETLINK_URELEASE, &n); + } + + module_put(nlk->module); + + netlink_table_grab(); + if (netlink_is_kernel(sk)) { + BUG_ON(nl_table[sk->sk_protocol].registered == 0); + if (--nl_table[sk->sk_protocol].registered == 0) { + kfree(nl_table[sk->sk_protocol].listeners); + nl_table[sk->sk_protocol].module = NULL; + nl_table[sk->sk_protocol].registered = 0; + } + } else if (nlk->subscriptions) + netlink_update_listeners(sk); + netlink_table_ungrab(); + + kfree(nlk->groups); + nlk->groups = NULL; + + local_bh_disable(); + sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); + local_bh_enable(); + sock_put(sk); + return 0; +} + +static int netlink_autobind(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct net *net = sock_net(sk); + struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; + struct hlist_head *head; + struct sock *osk; + struct hlist_node *node; + s32 pid = task_tgid_vnr(current); + int err; + static s32 rover = -4097; + +retry: + cond_resched(); + netlink_table_grab(); + head = nl_pid_hashfn(hash, pid); + sk_for_each(osk, node, head) { + if (!net_eq(sock_net(osk), net)) + continue; + if (nlk_sk(osk)->pid == pid) { + /* Bind collision, search negative pid values. */ + pid = rover--; + if (rover > -4097) + rover = -4097; + netlink_table_ungrab(); + goto retry; + } + } + netlink_table_ungrab(); + + err = netlink_insert(sk, net, pid); + if (err == -EADDRINUSE) + goto retry; + + /* If 2 threads race to autobind, that is fine. */ + if (err == -EBUSY) + err = 0; + + return err; +} + +static inline int netlink_capable(const struct socket *sock, unsigned int flag) +{ + return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || + capable(CAP_NET_ADMIN); +} + +static void +netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (nlk->subscriptions && !subscriptions) + __sk_del_bind_node(sk); + else if (!nlk->subscriptions && subscriptions) + sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); + nlk->subscriptions = subscriptions; +} + +static int netlink_realloc_groups(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + unsigned int groups; + unsigned long *new_groups; + int err = 0; + + netlink_table_grab(); + + groups = nl_table[sk->sk_protocol].groups; + if (!nl_table[sk->sk_protocol].registered) { + err = -ENOENT; + goto out_unlock; + } + + if (nlk->ngroups >= groups) + goto out_unlock; + + new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); + if (new_groups == NULL) { + err = -ENOMEM; + goto out_unlock; + } + memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, + NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); + + nlk->groups = new_groups; + nlk->ngroups = groups; + out_unlock: + netlink_table_ungrab(); + return err; +} + +static int netlink_bind(struct socket *sock, struct sockaddr *addr, + int addr_len) +{ + struct sock *sk = sock->sk; + struct net *net = sock_net(sk); + struct netlink_sock *nlk = nlk_sk(sk); + struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; + int err; + + if (nladdr->nl_family != AF_NETLINK) + return -EINVAL; + + /* Only superuser is allowed to listen multicasts */ + if (nladdr->nl_groups) { + if (!netlink_capable(sock, NL_NONROOT_RECV)) + return -EPERM; + err = netlink_realloc_groups(sk); + if (err) + return err; + } + + if (nlk->pid) { + if (nladdr->nl_pid != nlk->pid) + return -EINVAL; + } else { + err = nladdr->nl_pid ? + netlink_insert(sk, net, nladdr->nl_pid) : + netlink_autobind(sock); + if (err) + return err; + } + + if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) + return 0; + + netlink_table_grab(); + netlink_update_subscriptions(sk, nlk->subscriptions + + hweight32(nladdr->nl_groups) - + hweight32(nlk->groups[0])); + nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; + netlink_update_listeners(sk); + netlink_table_ungrab(); + + return 0; +} + +static int netlink_connect(struct socket *sock, struct sockaddr *addr, + int alen, int flags) +{ + int err = 0; + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; + + if (alen < sizeof(addr->sa_family)) + return -EINVAL; + + if (addr->sa_family == AF_UNSPEC) { + sk->sk_state = NETLINK_UNCONNECTED; + nlk->dst_pid = 0; + nlk->dst_group = 0; + return 0; + } + if (addr->sa_family != AF_NETLINK) + return -EINVAL; + + /* Only superuser is allowed to send multicasts */ + if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) + return -EPERM; + + if (!nlk->pid) + err = netlink_autobind(sock); + + if (err == 0) { + sk->sk_state = NETLINK_CONNECTED; + nlk->dst_pid = nladdr->nl_pid; + nlk->dst_group = ffs(nladdr->nl_groups); + } + + return err; +} + +static int netlink_getname(struct socket *sock, struct sockaddr *addr, + int *addr_len, int peer) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); + + nladdr->nl_family = AF_NETLINK; + nladdr->nl_pad = 0; + *addr_len = sizeof(*nladdr); + + if (peer) { + nladdr->nl_pid = nlk->dst_pid; + nladdr->nl_groups = netlink_group_mask(nlk->dst_group); + } else { + nladdr->nl_pid = nlk->pid; + nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; + } + return 0; +} + +static void netlink_overrun(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) { + if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { + sk->sk_err = ENOBUFS; + sk->sk_error_report(sk); + } + } + atomic_inc(&sk->sk_drops); +} + +static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) +{ + struct sock *sock; + struct netlink_sock *nlk; + + sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid); + if (!sock) + return ERR_PTR(-ECONNREFUSED); + + /* Don't bother queuing skb if kernel socket has no input function */ + nlk = nlk_sk(sock); + if (sock->sk_state == NETLINK_CONNECTED && + nlk->dst_pid != nlk_sk(ssk)->pid) { + sock_put(sock); + return ERR_PTR(-ECONNREFUSED); + } + return sock; +} + +struct sock *netlink_getsockbyfilp(struct file *filp) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + struct sock *sock; + + if (!S_ISSOCK(inode->i_mode)) + return ERR_PTR(-ENOTSOCK); + + sock = SOCKET_I(inode)->sk; + if (sock->sk_family != AF_NETLINK) + return ERR_PTR(-EINVAL); + + sock_hold(sock); + return sock; +} + +/* + * Attach a skb to a netlink socket. + * The caller must hold a reference to the destination socket. On error, the + * reference is dropped. The skb is not send to the destination, just all + * all error checks are performed and memory in the queue is reserved. + * Return values: + * < 0: error. skb freed, reference to sock dropped. + * 0: continue + * 1: repeat lookup - reference dropped while waiting for socket memory. + */ +int netlink_attachskb(struct sock *sk, struct sk_buff *skb, + long *timeo, struct sock *ssk) +{ + struct netlink_sock *nlk; + + nlk = nlk_sk(sk); + + if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || + test_bit(0, &nlk->state)) { + DECLARE_WAITQUEUE(wait, current); + if (!*timeo) { + if (!ssk || netlink_is_kernel(ssk)) + netlink_overrun(sk); + sock_put(sk); + kfree_skb(skb); + return -EAGAIN; + } + + __set_current_state(TASK_INTERRUPTIBLE); + add_wait_queue(&nlk->wait, &wait); + + if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || + test_bit(0, &nlk->state)) && + !sock_flag(sk, SOCK_DEAD)) + *timeo = schedule_timeout(*timeo); + + __set_current_state(TASK_RUNNING); + remove_wait_queue(&nlk->wait, &wait); + sock_put(sk); + + if (signal_pending(current)) { + kfree_skb(skb); + return sock_intr_errno(*timeo); + } + return 1; + } + skb_set_owner_r(skb, sk); + return 0; +} + +static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) +{ + int len = skb->len; + + skb_queue_tail(&sk->sk_receive_queue, skb); + sk->sk_data_ready(sk, len); + return len; +} + +int netlink_sendskb(struct sock *sk, struct sk_buff *skb) +{ + int len = __netlink_sendskb(sk, skb); + + sock_put(sk); + return len; +} + +void netlink_detachskb(struct sock *sk, struct sk_buff *skb) +{ + kfree_skb(skb); + sock_put(sk); +} + +static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) +{ + int delta; + + skb_orphan(skb); + + delta = skb->end - skb->tail; + if (delta * 2 < skb->truesize) + return skb; + + if (skb_shared(skb)) { + struct sk_buff *nskb = skb_clone(skb, allocation); + if (!nskb) + return skb; + kfree_skb(skb); + skb = nskb; + } + + if (!pskb_expand_head(skb, 0, -delta, allocation)) + skb->truesize -= delta; + + return skb; +} + +static void netlink_rcv_wake(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (skb_queue_empty(&sk->sk_receive_queue)) + clear_bit(0, &nlk->state); + if (!test_bit(0, &nlk->state)) + wake_up_interruptible(&nlk->wait); +} + +static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb) +{ + int ret; + struct netlink_sock *nlk = nlk_sk(sk); + + ret = -ECONNREFUSED; + if (nlk->netlink_rcv != NULL) { + ret = skb->len; + skb_set_owner_r(skb, sk); + nlk->netlink_rcv(skb); + } + kfree_skb(skb); + sock_put(sk); + return ret; +} + +int netlink_unicast(struct sock *ssk, struct sk_buff *skb, + u32 pid, int nonblock) +{ + struct sock *sk; + int err; + long timeo; + + skb = netlink_trim(skb, gfp_any()); + + timeo = sock_sndtimeo(ssk, nonblock); +retry: + sk = netlink_getsockbypid(ssk, pid); + if (IS_ERR(sk)) { + kfree_skb(skb); + return PTR_ERR(sk); + } + if (netlink_is_kernel(sk)) + return netlink_unicast_kernel(sk, skb); + + if (sk_filter(sk, skb)) { + err = skb->len; + kfree_skb(skb); + sock_put(sk); + return err; + } + + err = netlink_attachskb(sk, skb, &timeo, ssk); + if (err == 1) + goto retry; + if (err) + return err; + + return netlink_sendskb(sk, skb); +} +EXPORT_SYMBOL(netlink_unicast); + +int netlink_has_listeners(struct sock *sk, unsigned int group) +{ + int res = 0; + struct listeners *listeners; + + BUG_ON(!netlink_is_kernel(sk)); + + rcu_read_lock(); + listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); + + if (group - 1 < nl_table[sk->sk_protocol].groups) + res = test_bit(group - 1, listeners->masks); + + rcu_read_unlock(); + + return res; +} +EXPORT_SYMBOL_GPL(netlink_has_listeners); + +static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) +{ + struct netlink_sock *nlk = nlk_sk(sk); + + if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && + !test_bit(0, &nlk->state)) { + skb_set_owner_r(skb, sk); + __netlink_sendskb(sk, skb); + return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); + } + return -1; +} + +struct netlink_broadcast_data { + struct sock *exclude_sk; + struct net *net; + u32 pid; + u32 group; + int failure; + int delivery_failure; + int congested; + int delivered; + gfp_t allocation; + struct sk_buff *skb, *skb2; + int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); + void *tx_data; +}; + +static int do_one_broadcast(struct sock *sk, + struct netlink_broadcast_data *p) +{ + struct netlink_sock *nlk = nlk_sk(sk); + int val; + + if (p->exclude_sk == sk) + goto out; + + if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || + !test_bit(p->group - 1, nlk->groups)) + goto out; + + if (!net_eq(sock_net(sk), p->net)) + goto out; + + if (p->failure) { + netlink_overrun(sk); + goto out; + } + + sock_hold(sk); + if (p->skb2 == NULL) { + if (skb_shared(p->skb)) { + p->skb2 = skb_clone(p->skb, p->allocation); + } else { + p->skb2 = skb_get(p->skb); + /* + * skb ownership may have been set when + * delivered to a previous socket. + */ + skb_orphan(p->skb2); + } + } + if (p->skb2 == NULL) { + netlink_overrun(sk); + /* Clone failed. Notify ALL listeners. */ + p->failure = 1; + if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR) + p->delivery_failure = 1; + } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { + kfree_skb(p->skb2); + p->skb2 = NULL; + } else if (sk_filter(sk, p->skb2)) { + kfree_skb(p->skb2); + p->skb2 = NULL; + } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { + netlink_overrun(sk); + if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR) + p->delivery_failure = 1; + } else { + p->congested |= val; + p->delivered = 1; + p->skb2 = NULL; + } + sock_put(sk); + +out: + return 0; +} + +int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid, + u32 group, gfp_t allocation, + int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), + void *filter_data) +{ + struct net *net = sock_net(ssk); + struct netlink_broadcast_data info; + struct hlist_node *node; + struct sock *sk; + + skb = netlink_trim(skb, allocation); + + info.exclude_sk = ssk; + info.net = net; + info.pid = pid; + info.group = group; + info.failure = 0; + info.delivery_failure = 0; + info.congested = 0; + info.delivered = 0; + info.allocation = allocation; + info.skb = skb; + info.skb2 = NULL; + info.tx_filter = filter; + info.tx_data = filter_data; + + /* While we sleep in clone, do not allow to change socket list */ + + netlink_lock_table(); + + sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) + do_one_broadcast(sk, &info); + + consume_skb(skb); + + netlink_unlock_table(); + + if (info.delivery_failure) { + kfree_skb(info.skb2); + return -ENOBUFS; + } else + consume_skb(info.skb2); + + if (info.delivered) { + if (info.congested && (allocation & __GFP_WAIT)) + yield(); + return 0; + } + return -ESRCH; +} +EXPORT_SYMBOL(netlink_broadcast_filtered); + +int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, + u32 group, gfp_t allocation) +{ + return netlink_broadcast_filtered(ssk, skb, pid, group, allocation, + NULL, NULL); +} +EXPORT_SYMBOL(netlink_broadcast); + +struct netlink_set_err_data { + struct sock *exclude_sk; + u32 pid; + u32 group; + int code; +}; + +static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) +{ + struct netlink_sock *nlk = nlk_sk(sk); + int ret = 0; + + if (sk == p->exclude_sk) + goto out; + + if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) + goto out; + + if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || + !test_bit(p->group - 1, nlk->groups)) + goto out; + + if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) { + ret = 1; + goto out; + } + + sk->sk_err = p->code; + sk->sk_error_report(sk); +out: + return ret; +} + +/** + * netlink_set_err - report error to broadcast listeners + * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() + * @pid: the PID of a process that we want to skip (if any) + * @groups: the broadcast group that will notice the error + * @code: error code, must be negative (as usual in kernelspace) + * + * This function returns the number of broadcast listeners that have set the + * NETLINK_RECV_NO_ENOBUFS socket option. + */ +int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) +{ + struct netlink_set_err_data info; + struct hlist_node *node; + struct sock *sk; + int ret = 0; + + info.exclude_sk = ssk; + info.pid = pid; + info.group = group; + /* sk->sk_err wants a positive error value */ + info.code = -code; + + read_lock(&nl_table_lock); + + sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) + ret += do_one_set_err(sk, &info); + + read_unlock(&nl_table_lock); + return ret; +} +EXPORT_SYMBOL(netlink_set_err); + +/* must be called with netlink table grabbed */ +static void netlink_update_socket_mc(struct netlink_sock *nlk, + unsigned int group, + int is_new) +{ + int old, new = !!is_new, subscriptions; + + old = test_bit(group - 1, nlk->groups); + subscriptions = nlk->subscriptions - old + new; + if (new) + __set_bit(group - 1, nlk->groups); + else + __clear_bit(group - 1, nlk->groups); + netlink_update_subscriptions(&nlk->sk, subscriptions); + netlink_update_listeners(&nlk->sk); +} + +static int netlink_setsockopt(struct socket *sock, int level, int optname, + char __user *optval, unsigned int optlen) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + unsigned int val = 0; + int err; + + if (level != SOL_NETLINK) + return -ENOPROTOOPT; + + if (optlen >= sizeof(int) && + get_user(val, (unsigned int __user *)optval)) + return -EFAULT; + + switch (optname) { + case NETLINK_PKTINFO: + if (val) + nlk->flags |= NETLINK_RECV_PKTINFO; + else + nlk->flags &= ~NETLINK_RECV_PKTINFO; + err = 0; + break; + case NETLINK_ADD_MEMBERSHIP: + case NETLINK_DROP_MEMBERSHIP: { + if (!netlink_capable(sock, NL_NONROOT_RECV)) + return -EPERM; + err = netlink_realloc_groups(sk); + if (err) + return err; + if (!val || val - 1 >= nlk->ngroups) + return -EINVAL; + netlink_table_grab(); + netlink_update_socket_mc(nlk, val, + optname == NETLINK_ADD_MEMBERSHIP); + netlink_table_ungrab(); + err = 0; + break; + } + case NETLINK_BROADCAST_ERROR: + if (val) + nlk->flags |= NETLINK_BROADCAST_SEND_ERROR; + else + nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR; + err = 0; + break; + case NETLINK_NO_ENOBUFS: + if (val) { + nlk->flags |= NETLINK_RECV_NO_ENOBUFS; + clear_bit(0, &nlk->state); + wake_up_interruptible(&nlk->wait); + } else + nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS; + err = 0; + break; + default: + err = -ENOPROTOOPT; + } + return err; +} + +static int netlink_getsockopt(struct socket *sock, int level, int optname, + char __user *optval, int __user *optlen) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + int len, val, err; + + if (level != SOL_NETLINK) + return -ENOPROTOOPT; + + if (get_user(len, optlen)) + return -EFAULT; + if (len < 0) + return -EINVAL; + + switch (optname) { + case NETLINK_PKTINFO: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; + if (put_user(len, optlen) || + put_user(val, optval)) + return -EFAULT; + err = 0; + break; + case NETLINK_BROADCAST_ERROR: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0; + if (put_user(len, optlen) || + put_user(val, optval)) + return -EFAULT; + err = 0; + break; + case NETLINK_NO_ENOBUFS: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0; + if (put_user(len, optlen) || + put_user(val, optval)) + return -EFAULT; + err = 0; + break; + default: + err = -ENOPROTOOPT; + } + return err; +} + +static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) +{ + struct nl_pktinfo info; + + info.group = NETLINK_CB(skb).dst_group; + put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); +} + +static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, + struct msghdr *msg, size_t len) +{ + struct sock_iocb *siocb = kiocb_to_siocb(kiocb); + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + struct sockaddr_nl *addr = msg->msg_name; + u32 dst_pid; + u32 dst_group; + struct sk_buff *skb; + int err; + struct scm_cookie scm; + + if (msg->msg_flags&MSG_OOB) + return -EOPNOTSUPP; + + if (NULL == siocb->scm) + siocb->scm = &scm; + + err = scm_send(sock, msg, siocb->scm, true); + if (err < 0) + return err; + + if (msg->msg_namelen) { + err = -EINVAL; + if (addr->nl_family != AF_NETLINK) + goto out; + dst_pid = addr->nl_pid; + dst_group = ffs(addr->nl_groups); + err = -EPERM; + if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND)) + goto out; + } else { + dst_pid = nlk->dst_pid; + dst_group = nlk->dst_group; + } + + if (!nlk->pid) { + err = netlink_autobind(sock); + if (err) + goto out; + } + + err = -EMSGSIZE; + if (len > sk->sk_sndbuf - 32) + goto out; + err = -ENOBUFS; + skb = alloc_skb(len, GFP_KERNEL); + if (skb == NULL) + goto out; + + NETLINK_CB(skb).pid = nlk->pid; + NETLINK_CB(skb).dst_group = dst_group; + memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); + + err = -EFAULT; + if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { + kfree_skb(skb); + goto out; + } + + err = security_netlink_send(sk, skb); + if (err) { + kfree_skb(skb); + goto out; + } + + if (dst_group) { + atomic_inc(&skb->users); + netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); + } + err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); + +out: + scm_destroy(siocb->scm); + return err; +} + +static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, + struct msghdr *msg, size_t len, + int flags) +{ + struct sock_iocb *siocb = kiocb_to_siocb(kiocb); + struct scm_cookie scm; + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + int noblock = flags&MSG_DONTWAIT; + size_t copied; + struct sk_buff *skb, *data_skb; + int err, ret; + + if (flags&MSG_OOB) + return -EOPNOTSUPP; + + copied = 0; + + skb = skb_recv_datagram(sk, flags, noblock, &err); + if (skb == NULL) + goto out; + + data_skb = skb; + +#ifdef CONFIG_COMPAT_NETLINK_MESSAGES + if (unlikely(skb_shinfo(skb)->frag_list)) { + /* + * If this skb has a frag_list, then here that means that we + * will have to use the frag_list skb's data for compat tasks + * and the regular skb's data for normal (non-compat) tasks. + * + * If we need to send the compat skb, assign it to the + * 'data_skb' variable so that it will be used below for data + * copying. We keep 'skb' for everything else, including + * freeing both later. + */ + if (flags & MSG_CMSG_COMPAT) + data_skb = skb_shinfo(skb)->frag_list; + } +#endif + + msg->msg_namelen = 0; + + copied = data_skb->len; + if (len < copied) { + msg->msg_flags |= MSG_TRUNC; + copied = len; + } + + skb_reset_transport_header(data_skb); + err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied); + + if (msg->msg_name) { + struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name; + addr->nl_family = AF_NETLINK; + addr->nl_pad = 0; + addr->nl_pid = NETLINK_CB(skb).pid; + addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); + msg->msg_namelen = sizeof(*addr); + } + + if (nlk->flags & NETLINK_RECV_PKTINFO) + netlink_cmsg_recv_pktinfo(msg, skb); + + if (NULL == siocb->scm) { + memset(&scm, 0, sizeof(scm)); + siocb->scm = &scm; + } + siocb->scm->creds = *NETLINK_CREDS(skb); + if (flags & MSG_TRUNC) + copied = data_skb->len; + + skb_free_datagram(sk, skb); + + if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { + ret = netlink_dump(sk); + if (ret) { + sk->sk_err = ret; + sk->sk_error_report(sk); + } + } + + scm_recv(sock, msg, siocb->scm, flags); +out: + netlink_rcv_wake(sk); + return err ? : copied; +} + +static void netlink_data_ready(struct sock *sk, int len) +{ + BUG(); +} + +/* + * We export these functions to other modules. They provide a + * complete set of kernel non-blocking support for message + * queueing. + */ + +struct sock * +netlink_kernel_create(struct net *net, int unit, unsigned int groups, + void (*input)(struct sk_buff *skb), + struct mutex *cb_mutex, struct module *module) +{ + struct socket *sock; + struct sock *sk; + struct netlink_sock *nlk; + struct listeners *listeners = NULL; + + BUG_ON(!nl_table); + + if (unit < 0 || unit >= MAX_LINKS) + return NULL; + + if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) + return NULL; + + /* + * We have to just have a reference on the net from sk, but don't + * get_net it. Besides, we cannot get and then put the net here. + * So we create one inside init_net and the move it to net. + */ + + if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0) + goto out_sock_release_nosk; + + sk = sock->sk; + sk_change_net(sk, net); + + if (groups < 32) + groups = 32; + + listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); + if (!listeners) + goto out_sock_release; + + sk->sk_data_ready = netlink_data_ready; + if (input) + nlk_sk(sk)->netlink_rcv = input; + + if (netlink_insert(sk, net, 0)) + goto out_sock_release; + + nlk = nlk_sk(sk); + nlk->flags |= NETLINK_KERNEL_SOCKET; + + netlink_table_grab(); + if (!nl_table[unit].registered) { + nl_table[unit].groups = groups; + rcu_assign_pointer(nl_table[unit].listeners, listeners); + nl_table[unit].cb_mutex = cb_mutex; + nl_table[unit].module = module; + nl_table[unit].registered = 1; + } else { + kfree(listeners); + nl_table[unit].registered++; + } + netlink_table_ungrab(); + return sk; + +out_sock_release: + kfree(listeners); + netlink_kernel_release(sk); + return NULL; + +out_sock_release_nosk: + sock_release(sock); + return NULL; +} +EXPORT_SYMBOL(netlink_kernel_create); + + +void +netlink_kernel_release(struct sock *sk) +{ + sk_release_kernel(sk); +} +EXPORT_SYMBOL(netlink_kernel_release); + +int __netlink_change_ngroups(struct sock *sk, unsigned int groups) +{ + struct listeners *new, *old; + struct netlink_table *tbl = &nl_table[sk->sk_protocol]; + + if (groups < 32) + groups = 32; + + if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { + new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); + if (!new) + return -ENOMEM; + old = rcu_dereference_protected(tbl->listeners, 1); + memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); + rcu_assign_pointer(tbl->listeners, new); + + kfree_rcu(old, rcu); + } + tbl->groups = groups; + + return 0; +} + +/** + * netlink_change_ngroups - change number of multicast groups + * + * This changes the number of multicast groups that are available + * on a certain netlink family. Note that it is not possible to + * change the number of groups to below 32. Also note that it does + * not implicitly call netlink_clear_multicast_users() when the + * number of groups is reduced. + * + * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). + * @groups: The new number of groups. + */ +int netlink_change_ngroups(struct sock *sk, unsigned int groups) +{ + int err; + + netlink_table_grab(); + err = __netlink_change_ngroups(sk, groups); + netlink_table_ungrab(); + + return err; +} + +void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) +{ + struct sock *sk; + struct hlist_node *node; + struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; + + sk_for_each_bound(sk, node, &tbl->mc_list) + netlink_update_socket_mc(nlk_sk(sk), group, 0); +} + +/** + * netlink_clear_multicast_users - kick off multicast listeners + * + * This function removes all listeners from the given group. + * @ksk: The kernel netlink socket, as returned by + * netlink_kernel_create(). + * @group: The multicast group to clear. + */ +void netlink_clear_multicast_users(struct sock *ksk, unsigned int group) +{ + netlink_table_grab(); + __netlink_clear_multicast_users(ksk, group); + netlink_table_ungrab(); +} + +void netlink_set_nonroot(int protocol, unsigned int flags) +{ + if ((unsigned int)protocol < MAX_LINKS) + nl_table[protocol].nl_nonroot = flags; +} +EXPORT_SYMBOL(netlink_set_nonroot); + +static void netlink_destroy_callback(struct netlink_callback *cb) +{ + kfree_skb(cb->skb); + kfree(cb); +} + +struct nlmsghdr * +__nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags) +{ + struct nlmsghdr *nlh; + int size = NLMSG_LENGTH(len); + + nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size)); + nlh->nlmsg_type = type; + nlh->nlmsg_len = size; + nlh->nlmsg_flags = flags; + nlh->nlmsg_pid = pid; + nlh->nlmsg_seq = seq; + if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) + memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size); + return nlh; +} +EXPORT_SYMBOL(__nlmsg_put); + +/* + * It looks a bit ugly. + * It would be better to create kernel thread. + */ + +static int netlink_dump(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + struct netlink_callback *cb; + struct sk_buff *skb = NULL; + struct nlmsghdr *nlh; + int len, err = -ENOBUFS; + int alloc_size; + + mutex_lock(nlk->cb_mutex); + + cb = nlk->cb; + if (cb == NULL) { + err = -EINVAL; + goto errout_skb; + } + + alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); + + skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL); + if (!skb) + goto errout_skb; + + len = cb->dump(skb, cb); + + if (len > 0) { + mutex_unlock(nlk->cb_mutex); + + if (sk_filter(sk, skb)) + kfree_skb(skb); + else + __netlink_sendskb(sk, skb); + return 0; + } + + nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); + if (!nlh) + goto errout_skb; + + nl_dump_check_consistent(cb, nlh); + + memcpy(nlmsg_data(nlh), &len, sizeof(len)); + + if (sk_filter(sk, skb)) + kfree_skb(skb); + else + __netlink_sendskb(sk, skb); + + if (cb->done) + cb->done(cb); + nlk->cb = NULL; + mutex_unlock(nlk->cb_mutex); + + netlink_destroy_callback(cb); + return 0; + +errout_skb: + mutex_unlock(nlk->cb_mutex); + kfree_skb(skb); + return err; +} + +int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control) +{ + struct netlink_callback *cb; + struct sock *sk; + struct netlink_sock *nlk; + int ret; + + cb = kzalloc(sizeof(*cb), GFP_KERNEL); + if (cb == NULL) + return -ENOBUFS; + + cb->dump = control->dump; + cb->done = control->done; + cb->nlh = nlh; + cb->data = control->data; + cb->min_dump_alloc = control->min_dump_alloc; + atomic_inc(&skb->users); + cb->skb = skb; + + sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid); + if (sk == NULL) { + netlink_destroy_callback(cb); + return -ECONNREFUSED; + } + nlk = nlk_sk(sk); + /* A dump is in progress... */ + mutex_lock(nlk->cb_mutex); + if (nlk->cb) { + mutex_unlock(nlk->cb_mutex); + netlink_destroy_callback(cb); + sock_put(sk); + return -EBUSY; + } + nlk->cb = cb; + mutex_unlock(nlk->cb_mutex); + + ret = netlink_dump(sk); + + sock_put(sk); + + if (ret) + return ret; + + /* We successfully started a dump, by returning -EINTR we + * signal not to send ACK even if it was requested. + */ + return -EINTR; +} +EXPORT_SYMBOL(netlink_dump_start); + +void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) +{ + struct sk_buff *skb; + struct nlmsghdr *rep; + struct nlmsgerr *errmsg; + size_t payload = sizeof(*errmsg); + + /* error messages get the original request appened */ + if (err) + payload += nlmsg_len(nlh); + + skb = nlmsg_new(payload, GFP_KERNEL); + if (!skb) { + struct sock *sk; + + sk = netlink_lookup(sock_net(in_skb->sk), + in_skb->sk->sk_protocol, + NETLINK_CB(in_skb).pid); + if (sk) { + sk->sk_err = ENOBUFS; + sk->sk_error_report(sk); + sock_put(sk); + } + return; + } + + rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, + NLMSG_ERROR, payload, 0); + errmsg = nlmsg_data(rep); + errmsg->error = err; + memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh)); + netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); +} +EXPORT_SYMBOL(netlink_ack); + +int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, + struct nlmsghdr *)) +{ + struct nlmsghdr *nlh; + int err; + + while (skb->len >= nlmsg_total_size(0)) { + int msglen; + + nlh = nlmsg_hdr(skb); + err = 0; + + if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) + return 0; + + /* Only requests are handled by the kernel */ + if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) + goto ack; + + /* Skip control messages */ + if (nlh->nlmsg_type < NLMSG_MIN_TYPE) + goto ack; + + err = cb(skb, nlh); + if (err == -EINTR) + goto skip; + +ack: + if (nlh->nlmsg_flags & NLM_F_ACK || err) + netlink_ack(skb, nlh, err); + +skip: + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + skb_pull(skb, msglen); + } + + return 0; +} +EXPORT_SYMBOL(netlink_rcv_skb); + +/** + * nlmsg_notify - send a notification netlink message + * @sk: netlink socket to use + * @skb: notification message + * @pid: destination netlink pid for reports or 0 + * @group: destination multicast group or 0 + * @report: 1 to report back, 0 to disable + * @flags: allocation flags + */ +int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid, + unsigned int group, int report, gfp_t flags) +{ + int err = 0; + + if (group) { + int exclude_pid = 0; + + if (report) { + atomic_inc(&skb->users); + exclude_pid = pid; + } + + /* errors reported via destination sk->sk_err, but propagate + * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ + err = nlmsg_multicast(sk, skb, exclude_pid, group, flags); + } + + if (report) { + int err2; + + err2 = nlmsg_unicast(sk, skb, pid); + if (!err || err == -ESRCH) + err = err2; + } + + return err; +} +EXPORT_SYMBOL(nlmsg_notify); + +#ifdef CONFIG_PROC_FS +struct nl_seq_iter { + struct seq_net_private p; + int link; + int hash_idx; +}; + +static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) +{ + struct nl_seq_iter *iter = seq->private; + int i, j; + struct sock *s; + struct hlist_node *node; + loff_t off = 0; + + for (i = 0; i < MAX_LINKS; i++) { + struct nl_pid_hash *hash = &nl_table[i].hash; + + for (j = 0; j <= hash->mask; j++) { + sk_for_each(s, node, &hash->table[j]) { + if (sock_net(s) != seq_file_net(seq)) + continue; + if (off == pos) { + iter->link = i; + iter->hash_idx = j; + return s; + } + ++off; + } + } + } + return NULL; +} + +static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(nl_table_lock) +{ + read_lock(&nl_table_lock); + return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; +} + +static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct sock *s; + struct nl_seq_iter *iter; + int i, j; + + ++*pos; + + if (v == SEQ_START_TOKEN) + return netlink_seq_socket_idx(seq, 0); + + iter = seq->private; + s = v; + do { + s = sk_next(s); + } while (s && sock_net(s) != seq_file_net(seq)); + if (s) + return s; + + i = iter->link; + j = iter->hash_idx + 1; + + do { + struct nl_pid_hash *hash = &nl_table[i].hash; + + for (; j <= hash->mask; j++) { + s = sk_head(&hash->table[j]); + while (s && sock_net(s) != seq_file_net(seq)) + s = sk_next(s); + if (s) { + iter->link = i; + iter->hash_idx = j; + return s; + } + } + + j = 0; + } while (++i < MAX_LINKS); + + return NULL; +} + +static void netlink_seq_stop(struct seq_file *seq, void *v) + __releases(nl_table_lock) +{ + read_unlock(&nl_table_lock); +} + + +static int netlink_seq_show(struct seq_file *seq, void *v) +{ + if (v == SEQ_START_TOKEN) + seq_puts(seq, + "sk Eth Pid Groups " + "Rmem Wmem Dump Locks Drops Inode\n"); + else { + struct sock *s = v; + struct netlink_sock *nlk = nlk_sk(s); + + seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n", + s, + s->sk_protocol, + nlk->pid, + nlk->groups ? (u32)nlk->groups[0] : 0, + sk_rmem_alloc_get(s), + sk_wmem_alloc_get(s), + nlk->cb, + atomic_read(&s->sk_refcnt), + atomic_read(&s->sk_drops), + sock_i_ino(s) + ); + + } + return 0; +} + +static const struct seq_operations netlink_seq_ops = { + .start = netlink_seq_start, + .next = netlink_seq_next, + .stop = netlink_seq_stop, + .show = netlink_seq_show, +}; + + +static int netlink_seq_open(struct inode *inode, struct file *file) +{ + return seq_open_net(inode, file, &netlink_seq_ops, + sizeof(struct nl_seq_iter)); +} + +static const struct file_operations netlink_seq_fops = { + .owner = THIS_MODULE, + .open = netlink_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net, +}; + +#endif + +int netlink_register_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&netlink_chain, nb); +} +EXPORT_SYMBOL(netlink_register_notifier); + +int netlink_unregister_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&netlink_chain, nb); +} +EXPORT_SYMBOL(netlink_unregister_notifier); + +static const struct proto_ops netlink_ops = { + .family = PF_NETLINK, + .owner = THIS_MODULE, + .release = netlink_release, + .bind = netlink_bind, + .connect = netlink_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = netlink_getname, + .poll = datagram_poll, + .ioctl = sock_no_ioctl, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .setsockopt = netlink_setsockopt, + .getsockopt = netlink_getsockopt, + .sendmsg = netlink_sendmsg, + .recvmsg = netlink_recvmsg, + .mmap = sock_no_mmap, + .sendpage = sock_no_sendpage, +}; + +static const struct net_proto_family netlink_family_ops = { + .family = PF_NETLINK, + .create = netlink_create, + .owner = THIS_MODULE, /* for consistency 8) */ +}; + +static int __net_init netlink_net_init(struct net *net) +{ +#ifdef CONFIG_PROC_FS + if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops)) + return -ENOMEM; +#endif + return 0; +} + +static void __net_exit netlink_net_exit(struct net *net) +{ +#ifdef CONFIG_PROC_FS + proc_net_remove(net, "netlink"); +#endif +} + +static void __init netlink_add_usersock_entry(void) +{ + struct listeners *listeners; + int groups = 32; + + listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); + if (!listeners) + panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); + + netlink_table_grab(); + + nl_table[NETLINK_USERSOCK].groups = groups; + rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); + nl_table[NETLINK_USERSOCK].module = THIS_MODULE; + nl_table[NETLINK_USERSOCK].registered = 1; + + netlink_table_ungrab(); +} + +static struct pernet_operations __net_initdata netlink_net_ops = { + .init = netlink_net_init, + .exit = netlink_net_exit, +}; + +static int __init netlink_proto_init(void) +{ + struct sk_buff *dummy_skb; + int i; + unsigned long limit; + unsigned int order; + int err = proto_register(&netlink_proto, 0); + + if (err != 0) + goto out; + + BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)); + + nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); + if (!nl_table) + goto panic; + + if (totalram_pages >= (128 * 1024)) + limit = totalram_pages >> (21 - PAGE_SHIFT); + else + limit = totalram_pages >> (23 - PAGE_SHIFT); + + order = get_bitmask_order(limit) - 1 + PAGE_SHIFT; + limit = (1UL << order) / sizeof(struct hlist_head); + order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1; + + for (i = 0; i < MAX_LINKS; i++) { + struct nl_pid_hash *hash = &nl_table[i].hash; + + hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table)); + if (!hash->table) { + while (i-- > 0) + nl_pid_hash_free(nl_table[i].hash.table, + 1 * sizeof(*hash->table)); + kfree(nl_table); + goto panic; + } + hash->max_shift = order; + hash->shift = 0; + hash->mask = 0; + hash->rehash_time = jiffies; + } + + netlink_add_usersock_entry(); + + sock_register(&netlink_family_ops); + register_pernet_subsys(&netlink_net_ops); + /* The netlink device handler may be needed early. */ + rtnetlink_init(); +out: + return err; +panic: + panic("netlink_init: Cannot allocate nl_table\n"); +} + +core_initcall(netlink_proto_init); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c new file mode 100644 index 00000000..9f40441d --- /dev/null +++ b/net/netlink/genetlink.c @@ -0,0 +1,1014 @@ +/* + * NETLINK Generic Netlink Family + * + * Authors: Jamal Hadi Salim + * Thomas Graf <tgraf@suug.ch> + * Johannes Berg <johannes@sipsolutions.net> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/string.h> +#include <linux/skbuff.h> +#include <linux/mutex.h> +#include <linux/bitmap.h> +#include <net/sock.h> +#include <net/genetlink.h> + +static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ + +void genl_lock(void) +{ + mutex_lock(&genl_mutex); +} +EXPORT_SYMBOL(genl_lock); + +void genl_unlock(void) +{ + mutex_unlock(&genl_mutex); +} +EXPORT_SYMBOL(genl_unlock); + +#ifdef CONFIG_PROVE_LOCKING +int lockdep_genl_is_held(void) +{ + return lockdep_is_held(&genl_mutex); +} +EXPORT_SYMBOL(lockdep_genl_is_held); +#endif + +#define GENL_FAM_TAB_SIZE 16 +#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) + +static struct list_head family_ht[GENL_FAM_TAB_SIZE]; +/* + * Bitmap of multicast groups that are currently in use. + * + * To avoid an allocation at boot of just one unsigned long, + * declare it global instead. + * Bit 0 is marked as already used since group 0 is invalid. + */ +static unsigned long mc_group_start = 0x1; +static unsigned long *mc_groups = &mc_group_start; +static unsigned long mc_groups_longs = 1; + +static int genl_ctrl_event(int event, void *data); + +static inline unsigned int genl_family_hash(unsigned int id) +{ + return id & GENL_FAM_TAB_MASK; +} + +static inline struct list_head *genl_family_chain(unsigned int id) +{ + return &family_ht[genl_family_hash(id)]; +} + +static struct genl_family *genl_family_find_byid(unsigned int id) +{ + struct genl_family *f; + + list_for_each_entry(f, genl_family_chain(id), family_list) + if (f->id == id) + return f; + + return NULL; +} + +static struct genl_family *genl_family_find_byname(char *name) +{ + struct genl_family *f; + int i; + + for (i = 0; i < GENL_FAM_TAB_SIZE; i++) + list_for_each_entry(f, genl_family_chain(i), family_list) + if (strcmp(f->name, name) == 0) + return f; + + return NULL; +} + +static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) +{ + struct genl_ops *ops; + + list_for_each_entry(ops, &family->ops_list, ops_list) + if (ops->cmd == cmd) + return ops; + + return NULL; +} + +/* Of course we are going to have problems once we hit + * 2^16 alive types, but that can only happen by year 2K +*/ +static u16 genl_generate_id(void) +{ + static u16 id_gen_idx = GENL_MIN_ID; + int i; + + for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { + if (!genl_family_find_byid(id_gen_idx)) + return id_gen_idx; + if (++id_gen_idx > GENL_MAX_ID) + id_gen_idx = GENL_MIN_ID; + } + + return 0; +} + +static struct genl_multicast_group notify_grp; + +/** + * genl_register_mc_group - register a multicast group + * + * Registers the specified multicast group and notifies userspace + * about the new group. + * + * Returns 0 on success or a negative error code. + * + * @family: The generic netlink family the group shall be registered for. + * @grp: The group to register, must have a name. + */ +int genl_register_mc_group(struct genl_family *family, + struct genl_multicast_group *grp) +{ + int id; + unsigned long *new_groups; + int err = 0; + + BUG_ON(grp->name[0] == '\0'); + + genl_lock(); + + /* special-case our own group */ + if (grp == ¬ify_grp) + id = GENL_ID_CTRL; + else + id = find_first_zero_bit(mc_groups, + mc_groups_longs * BITS_PER_LONG); + + + if (id >= mc_groups_longs * BITS_PER_LONG) { + size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long); + + if (mc_groups == &mc_group_start) { + new_groups = kzalloc(nlen, GFP_KERNEL); + if (!new_groups) { + err = -ENOMEM; + goto out; + } + mc_groups = new_groups; + *mc_groups = mc_group_start; + } else { + new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); + if (!new_groups) { + err = -ENOMEM; + goto out; + } + mc_groups = new_groups; + mc_groups[mc_groups_longs] = 0; + } + mc_groups_longs++; + } + + if (family->netnsok) { + struct net *net; + + netlink_table_grab(); + rcu_read_lock(); + for_each_net_rcu(net) { + err = __netlink_change_ngroups(net->genl_sock, + mc_groups_longs * BITS_PER_LONG); + if (err) { + /* + * No need to roll back, can only fail if + * memory allocation fails and then the + * number of _possible_ groups has been + * increased on some sockets which is ok. + */ + rcu_read_unlock(); + netlink_table_ungrab(); + goto out; + } + } + rcu_read_unlock(); + netlink_table_ungrab(); + } else { + err = netlink_change_ngroups(init_net.genl_sock, + mc_groups_longs * BITS_PER_LONG); + if (err) + goto out; + } + + grp->id = id; + set_bit(id, mc_groups); + list_add_tail(&grp->list, &family->mcast_groups); + grp->family = family; + + genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp); + out: + genl_unlock(); + return err; +} +EXPORT_SYMBOL(genl_register_mc_group); + +static void __genl_unregister_mc_group(struct genl_family *family, + struct genl_multicast_group *grp) +{ + struct net *net; + BUG_ON(grp->family != family); + + netlink_table_grab(); + rcu_read_lock(); + for_each_net_rcu(net) + __netlink_clear_multicast_users(net->genl_sock, grp->id); + rcu_read_unlock(); + netlink_table_ungrab(); + + clear_bit(grp->id, mc_groups); + list_del(&grp->list); + genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); + grp->id = 0; + grp->family = NULL; +} + +/** + * genl_unregister_mc_group - unregister a multicast group + * + * Unregisters the specified multicast group and notifies userspace + * about it. All current listeners on the group are removed. + * + * Note: It is not necessary to unregister all multicast groups before + * unregistering the family, unregistering the family will cause + * all assigned multicast groups to be unregistered automatically. + * + * @family: Generic netlink family the group belongs to. + * @grp: The group to unregister, must have been registered successfully + * previously. + */ +void genl_unregister_mc_group(struct genl_family *family, + struct genl_multicast_group *grp) +{ + genl_lock(); + __genl_unregister_mc_group(family, grp); + genl_unlock(); +} +EXPORT_SYMBOL(genl_unregister_mc_group); + +static void genl_unregister_mc_groups(struct genl_family *family) +{ + struct genl_multicast_group *grp, *tmp; + + list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) + __genl_unregister_mc_group(family, grp); +} + +/** + * genl_register_ops - register generic netlink operations + * @family: generic netlink family + * @ops: operations to be registered + * + * Registers the specified operations and assigns them to the specified + * family. Either a doit or dumpit callback must be specified or the + * operation will fail. Only one operation structure per command + * identifier may be registered. + * + * See include/net/genetlink.h for more documenation on the operations + * structure. + * + * Returns 0 on success or a negative error code. + */ +int genl_register_ops(struct genl_family *family, struct genl_ops *ops) +{ + int err = -EINVAL; + + if (ops->dumpit == NULL && ops->doit == NULL) + goto errout; + + if (genl_get_cmd(ops->cmd, family)) { + err = -EEXIST; + goto errout; + } + + if (ops->dumpit) + ops->flags |= GENL_CMD_CAP_DUMP; + if (ops->doit) + ops->flags |= GENL_CMD_CAP_DO; + if (ops->policy) + ops->flags |= GENL_CMD_CAP_HASPOL; + + genl_lock(); + list_add_tail(&ops->ops_list, &family->ops_list); + genl_unlock(); + + genl_ctrl_event(CTRL_CMD_NEWOPS, ops); + err = 0; +errout: + return err; +} +EXPORT_SYMBOL(genl_register_ops); + +/** + * genl_unregister_ops - unregister generic netlink operations + * @family: generic netlink family + * @ops: operations to be unregistered + * + * Unregisters the specified operations and unassigns them from the + * specified family. The operation blocks until the current message + * processing has finished and doesn't start again until the + * unregister process has finished. + * + * Note: It is not necessary to unregister all operations before + * unregistering the family, unregistering the family will cause + * all assigned operations to be unregistered automatically. + * + * Returns 0 on success or a negative error code. + */ +int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) +{ + struct genl_ops *rc; + + genl_lock(); + list_for_each_entry(rc, &family->ops_list, ops_list) { + if (rc == ops) { + list_del(&ops->ops_list); + genl_unlock(); + genl_ctrl_event(CTRL_CMD_DELOPS, ops); + return 0; + } + } + genl_unlock(); + + return -ENOENT; +} +EXPORT_SYMBOL(genl_unregister_ops); + +/** + * genl_register_family - register a generic netlink family + * @family: generic netlink family + * + * Registers the specified family after validating it first. Only one + * family may be registered with the same family name or identifier. + * The family id may equal GENL_ID_GENERATE causing an unique id to + * be automatically generated and assigned. + * + * Return 0 on success or a negative error code. + */ +int genl_register_family(struct genl_family *family) +{ + int err = -EINVAL; + + if (family->id && family->id < GENL_MIN_ID) + goto errout; + + if (family->id > GENL_MAX_ID) + goto errout; + + INIT_LIST_HEAD(&family->ops_list); + INIT_LIST_HEAD(&family->mcast_groups); + + genl_lock(); + + if (genl_family_find_byname(family->name)) { + err = -EEXIST; + goto errout_locked; + } + + if (family->id == GENL_ID_GENERATE) { + u16 newid = genl_generate_id(); + + if (!newid) { + err = -ENOMEM; + goto errout_locked; + } + + family->id = newid; + } else if (genl_family_find_byid(family->id)) { + err = -EEXIST; + goto errout_locked; + } + + if (family->maxattr) { + family->attrbuf = kmalloc((family->maxattr+1) * + sizeof(struct nlattr *), GFP_KERNEL); + if (family->attrbuf == NULL) { + err = -ENOMEM; + goto errout_locked; + } + } else + family->attrbuf = NULL; + + list_add_tail(&family->family_list, genl_family_chain(family->id)); + genl_unlock(); + + genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); + + return 0; + +errout_locked: + genl_unlock(); +errout: + return err; +} +EXPORT_SYMBOL(genl_register_family); + +/** + * genl_register_family_with_ops - register a generic netlink family + * @family: generic netlink family + * @ops: operations to be registered + * @n_ops: number of elements to register + * + * Registers the specified family and operations from the specified table. + * Only one family may be registered with the same family name or identifier. + * + * The family id may equal GENL_ID_GENERATE causing an unique id to + * be automatically generated and assigned. + * + * Either a doit or dumpit callback must be specified for every registered + * operation or the function will fail. Only one operation structure per + * command identifier may be registered. + * + * See include/net/genetlink.h for more documenation on the operations + * structure. + * + * This is equivalent to calling genl_register_family() followed by + * genl_register_ops() for every operation entry in the table taking + * care to unregister the family on error path. + * + * Return 0 on success or a negative error code. + */ +int genl_register_family_with_ops(struct genl_family *family, + struct genl_ops *ops, size_t n_ops) +{ + int err, i; + + err = genl_register_family(family); + if (err) + return err; + + for (i = 0; i < n_ops; ++i, ++ops) { + err = genl_register_ops(family, ops); + if (err) + goto err_out; + } + return 0; +err_out: + genl_unregister_family(family); + return err; +} +EXPORT_SYMBOL(genl_register_family_with_ops); + +/** + * genl_unregister_family - unregister generic netlink family + * @family: generic netlink family + * + * Unregisters the specified family. + * + * Returns 0 on success or a negative error code. + */ +int genl_unregister_family(struct genl_family *family) +{ + struct genl_family *rc; + + genl_lock(); + + genl_unregister_mc_groups(family); + + list_for_each_entry(rc, genl_family_chain(family->id), family_list) { + if (family->id != rc->id || strcmp(rc->name, family->name)) + continue; + + list_del(&rc->family_list); + INIT_LIST_HEAD(&family->ops_list); + genl_unlock(); + + kfree(family->attrbuf); + genl_ctrl_event(CTRL_CMD_DELFAMILY, family); + return 0; + } + + genl_unlock(); + + return -ENOENT; +} +EXPORT_SYMBOL(genl_unregister_family); + +/** + * genlmsg_put - Add generic netlink header to netlink message + * @skb: socket buffer holding the message + * @pid: netlink pid the message is addressed to + * @seq: sequence number (usually the one of the sender) + * @family: generic netlink family + * @flags netlink message flags + * @cmd: generic netlink command + * + * Returns pointer to user specific header + */ +void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, + struct genl_family *family, int flags, u8 cmd) +{ + struct nlmsghdr *nlh; + struct genlmsghdr *hdr; + + nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN + + family->hdrsize, flags); + if (nlh == NULL) + return NULL; + + hdr = nlmsg_data(nlh); + hdr->cmd = cmd; + hdr->version = family->version; + hdr->reserved = 0; + + return (char *) hdr + GENL_HDRLEN; +} +EXPORT_SYMBOL(genlmsg_put); + +static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + struct genl_ops *ops; + struct genl_family *family; + struct net *net = sock_net(skb->sk); + struct genl_info info; + struct genlmsghdr *hdr = nlmsg_data(nlh); + int hdrlen, err; + + family = genl_family_find_byid(nlh->nlmsg_type); + if (family == NULL) + return -ENOENT; + + /* this family doesn't exist in this netns */ + if (!family->netnsok && !net_eq(net, &init_net)) + return -ENOENT; + + hdrlen = GENL_HDRLEN + family->hdrsize; + if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) + return -EINVAL; + + ops = genl_get_cmd(hdr->cmd, family); + if (ops == NULL) + return -EOPNOTSUPP; + + if ((ops->flags & GENL_ADMIN_PERM) && + !capable(CAP_NET_ADMIN)) + return -EPERM; + + if (nlh->nlmsg_flags & NLM_F_DUMP) { + if (ops->dumpit == NULL) + return -EOPNOTSUPP; + + genl_unlock(); + { + struct netlink_dump_control c = { + .dump = ops->dumpit, + .done = ops->done, + }; + err = netlink_dump_start(net->genl_sock, skb, nlh, &c); + } + genl_lock(); + return err; + } + + if (ops->doit == NULL) + return -EOPNOTSUPP; + + if (family->attrbuf) { + err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, + ops->policy); + if (err < 0) + return err; + } + + info.snd_seq = nlh->nlmsg_seq; + info.snd_pid = NETLINK_CB(skb).pid; + info.nlhdr = nlh; + info.genlhdr = nlmsg_data(nlh); + info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; + info.attrs = family->attrbuf; + genl_info_net_set(&info, net); + memset(&info.user_ptr, 0, sizeof(info.user_ptr)); + + if (family->pre_doit) { + err = family->pre_doit(ops, skb, &info); + if (err) + return err; + } + + err = ops->doit(skb, &info); + + if (family->post_doit) + family->post_doit(ops, skb, &info); + + return err; +} + +static void genl_rcv(struct sk_buff *skb) +{ + genl_lock(); + netlink_rcv_skb(skb, &genl_rcv_msg); + genl_unlock(); +} + +/************************************************************************** + * Controller + **************************************************************************/ + +static struct genl_family genl_ctrl = { + .id = GENL_ID_CTRL, + .name = "nlctrl", + .version = 0x2, + .maxattr = CTRL_ATTR_MAX, + .netnsok = true, +}; + +static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, + u32 flags, struct sk_buff *skb, u8 cmd) +{ + void *hdr; + + hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); + if (hdr == NULL) + return -1; + + NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); + NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); + NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); + NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); + NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); + + if (!list_empty(&family->ops_list)) { + struct nlattr *nla_ops; + struct genl_ops *ops; + int idx = 1; + + nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); + if (nla_ops == NULL) + goto nla_put_failure; + + list_for_each_entry(ops, &family->ops_list, ops_list) { + struct nlattr *nest; + + nest = nla_nest_start(skb, idx++); + if (nest == NULL) + goto nla_put_failure; + + NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); + NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); + + nla_nest_end(skb, nest); + } + + nla_nest_end(skb, nla_ops); + } + + if (!list_empty(&family->mcast_groups)) { + struct genl_multicast_group *grp; + struct nlattr *nla_grps; + int idx = 1; + + nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); + if (nla_grps == NULL) + goto nla_put_failure; + + list_for_each_entry(grp, &family->mcast_groups, list) { + struct nlattr *nest; + + nest = nla_nest_start(skb, idx++); + if (nest == NULL) + goto nla_put_failure; + + NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); + NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, + grp->name); + + nla_nest_end(skb, nest); + } + nla_nest_end(skb, nla_grps); + } + + return genlmsg_end(skb, hdr); + +nla_put_failure: + genlmsg_cancel(skb, hdr); + return -EMSGSIZE; +} + +static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid, + u32 seq, u32 flags, struct sk_buff *skb, + u8 cmd) +{ + void *hdr; + struct nlattr *nla_grps; + struct nlattr *nest; + + hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); + if (hdr == NULL) + return -1; + + NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name); + NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id); + + nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); + if (nla_grps == NULL) + goto nla_put_failure; + + nest = nla_nest_start(skb, 1); + if (nest == NULL) + goto nla_put_failure; + + NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); + NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, + grp->name); + + nla_nest_end(skb, nest); + nla_nest_end(skb, nla_grps); + + return genlmsg_end(skb, hdr); + +nla_put_failure: + genlmsg_cancel(skb, hdr); + return -EMSGSIZE; +} + +static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) +{ + + int i, n = 0; + struct genl_family *rt; + struct net *net = sock_net(skb->sk); + int chains_to_skip = cb->args[0]; + int fams_to_skip = cb->args[1]; + + for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { + n = 0; + list_for_each_entry(rt, genl_family_chain(i), family_list) { + if (!rt->netnsok && !net_eq(net, &init_net)) + continue; + if (++n < fams_to_skip) + continue; + if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid, + cb->nlh->nlmsg_seq, NLM_F_MULTI, + skb, CTRL_CMD_NEWFAMILY) < 0) + goto errout; + } + + fams_to_skip = 0; + } + +errout: + cb->args[0] = i; + cb->args[1] = n; + + return skb->len; +} + +static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, + u32 pid, int seq, u8 cmd) +{ + struct sk_buff *skb; + int err; + + skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb == NULL) + return ERR_PTR(-ENOBUFS); + + err = ctrl_fill_info(family, pid, seq, 0, skb, cmd); + if (err < 0) { + nlmsg_free(skb); + return ERR_PTR(err); + } + + return skb; +} + +static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, + u32 pid, int seq, u8 cmd) +{ + struct sk_buff *skb; + int err; + + skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb == NULL) + return ERR_PTR(-ENOBUFS); + + err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd); + if (err < 0) { + nlmsg_free(skb); + return ERR_PTR(err); + } + + return skb; +} + +static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { + [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, + [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, + .len = GENL_NAMSIZ - 1 }, +}; + +static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) +{ + struct sk_buff *msg; + struct genl_family *res = NULL; + int err = -EINVAL; + + if (info->attrs[CTRL_ATTR_FAMILY_ID]) { + u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); + res = genl_family_find_byid(id); + err = -ENOENT; + } + + if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { + char *name; + + name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); + res = genl_family_find_byname(name); +#ifdef CONFIG_MODULES + if (res == NULL) { + genl_unlock(); + request_module("net-pf-%d-proto-%d-type-%s", + PF_NETLINK, NETLINK_GENERIC, name); + genl_lock(); + res = genl_family_find_byname(name); + } +#endif + err = -ENOENT; + } + + if (res == NULL) + return err; + + if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { + /* family doesn't exist here */ + return -ENOENT; + } + + msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq, + CTRL_CMD_NEWFAMILY); + if (IS_ERR(msg)) + return PTR_ERR(msg); + + return genlmsg_reply(msg, info); +} + +static int genl_ctrl_event(int event, void *data) +{ + struct sk_buff *msg; + struct genl_family *family; + struct genl_multicast_group *grp; + + /* genl is still initialising */ + if (!init_net.genl_sock) + return 0; + + switch (event) { + case CTRL_CMD_NEWFAMILY: + case CTRL_CMD_DELFAMILY: + family = data; + msg = ctrl_build_family_msg(family, 0, 0, event); + break; + case CTRL_CMD_NEWMCAST_GRP: + case CTRL_CMD_DELMCAST_GRP: + grp = data; + family = grp->family; + msg = ctrl_build_mcgrp_msg(data, 0, 0, event); + break; + default: + return -EINVAL; + } + + if (IS_ERR(msg)) + return PTR_ERR(msg); + + if (!family->netnsok) { + genlmsg_multicast_netns(&init_net, msg, 0, + GENL_ID_CTRL, GFP_KERNEL); + } else { + rcu_read_lock(); + genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC); + rcu_read_unlock(); + } + + return 0; +} + +static struct genl_ops genl_ctrl_ops = { + .cmd = CTRL_CMD_GETFAMILY, + .doit = ctrl_getfamily, + .dumpit = ctrl_dumpfamily, + .policy = ctrl_policy, +}; + +static struct genl_multicast_group notify_grp = { + .name = "notify", +}; + +static int __net_init genl_pernet_init(struct net *net) +{ + /* we'll bump the group number right afterwards */ + net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0, + genl_rcv, &genl_mutex, + THIS_MODULE); + + if (!net->genl_sock && net_eq(net, &init_net)) + panic("GENL: Cannot initialize generic netlink\n"); + + if (!net->genl_sock) + return -ENOMEM; + + return 0; +} + +static void __net_exit genl_pernet_exit(struct net *net) +{ + netlink_kernel_release(net->genl_sock); + net->genl_sock = NULL; +} + +static struct pernet_operations genl_pernet_ops = { + .init = genl_pernet_init, + .exit = genl_pernet_exit, +}; + +static int __init genl_init(void) +{ + int i, err; + + for (i = 0; i < GENL_FAM_TAB_SIZE; i++) + INIT_LIST_HEAD(&family_ht[i]); + + err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1); + if (err < 0) + goto problem; + + netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); + + err = register_pernet_subsys(&genl_pernet_ops); + if (err) + goto problem; + + err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); + if (err < 0) + goto problem; + + return 0; + +problem: + panic("GENL: Cannot register controller: %d\n", err); +} + +subsys_initcall(genl_init); + +static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group, + gfp_t flags) +{ + struct sk_buff *tmp; + struct net *net, *prev = NULL; + int err; + + for_each_net_rcu(net) { + if (prev) { + tmp = skb_clone(skb, flags); + if (!tmp) { + err = -ENOMEM; + goto error; + } + err = nlmsg_multicast(prev->genl_sock, tmp, + pid, group, flags); + if (err) + goto error; + } + + prev = net; + } + + return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags); + error: + kfree_skb(skb); + return err; +} + +int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group, + gfp_t flags) +{ + return genlmsg_mcast(skb, pid, group, flags); +} +EXPORT_SYMBOL(genlmsg_multicast_allns); + +void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group, + struct nlmsghdr *nlh, gfp_t flags) +{ + struct sock *sk = net->genl_sock; + int report = 0; + + if (nlh) + report = nlmsg_report(nlh); + + nlmsg_notify(sk, skb, pid, group, report, flags); +} +EXPORT_SYMBOL(genl_notify); |