/* * NETLINK Kernel-user communication protocol. * * Authors: Alan Cox <alan@redhat.com> * 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/smp_lock.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/selinux.h> #include <net/sock.h> #include <net/scm.h> #include <net/netlink.h> #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) 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; spinlock_t cb_lock; void (*data_ready)(struct sock *sk, int bytes); struct module *module; }; #define NETLINK_KERNEL_SOCKET 0x1 #define NETLINK_RECV_PKTINFO 0x2 static inline struct netlink_sock *nlk_sk(struct sock *sk) { return (struct netlink_sock *)sk; } 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; unsigned long *listeners; unsigned int nl_nonroot; unsigned int groups; 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 u32 netlink_group_mask(u32 group) { return group ? 1 << (group - 1) : 0; } static 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) { skb_queue_purge(&sk->sk_receive_queue); if (!sock_flag(sk, SOCK_DEAD)) { printk("Freeing alive netlink socket %p\n", sk); return; } BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc)); BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); BUG_TRAP(!nlk_sk(sk)->cb); BUG_TRAP(!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. */ static void netlink_table_grab(void) { 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); } } static __inline__ void netlink_table_ungrab(void) { 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 __inline__ struct sock *netlink_lookup(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 (nlk_sk(sk)->pid == pid) { sock_hold(sk); goto found; } } sk = NULL; found: read_unlock(&nl_table_lock); return sk; } static inline struct hlist_head *nl_pid_hash_alloc(size_t size) { if (size <= PAGE_SIZE) return kmalloc(size, GFP_ATOMIC); else return (struct hlist_head *) __get_free_pages(GFP_ATOMIC, get_order(size)); } static inline 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_alloc(size); if (!table) return 0; memset(table, 0, size); 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 < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) { mask = 0; sk_for_each_bound(sk, node, &tbl->mc_list) mask |= nlk_sk(sk)->groups[i]; tbl->listeners[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, 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 (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 socket *sock, int protocol) { struct sock *sk; struct netlink_sock *nlk; sock->ops = &netlink_ops; sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1); if (!sk) return -ENOMEM; sock_init_data(sock, sk); nlk = nlk_sk(sk); spin_lock_init(&nlk->cb_lock); init_waitqueue_head(&nlk->wait); sk->sk_destruct = netlink_sock_destruct; sk->sk_protocol = protocol; return 0; } static int netlink_create(struct socket *sock, int protocol) { struct module *module = NULL; struct netlink_sock *nlk; unsigned int groups; 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_KMOD 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; groups = nl_table[protocol].groups; netlink_unlock_table(); if ((err = __netlink_create(sock, protocol)) < 0) goto out_module; 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); nlk = nlk_sk(sk); spin_lock(&nlk->cb_lock); if (nlk->cb) { if (nlk->cb->done) nlk->cb->done(nlk->cb); netlink_destroy_callback(nlk->cb); nlk->cb = NULL; } spin_unlock(&nlk->cb_lock); /* OK. Socket is unlinked, and, therefore, no new packets will arrive */ sock_orphan(sk); sock->sk = NULL; wake_up_interruptible_all(&nlk->wait); skb_queue_purge(&sk->sk_write_queue); if (nlk->pid && !nlk->subscriptions) { struct netlink_notify n = { .protocol = sk->sk_protocol, .pid = nlk->pid, }; atomic_notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n); } if (nlk->module) module_put(nlk->module); netlink_table_grab(); if (nlk->flags & NETLINK_KERNEL_SOCKET) { 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; sock_put(sk); return 0; } static int netlink_autobind(struct socket *sock) { struct sock *sk = sock->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 = current->tgid; 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 (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, 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(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_alloc_groups(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); unsigned int groups; int err = 0; netlink_lock_table(); groups = nl_table[sk->sk_protocol].groups; if (!nl_table[sk->sk_protocol].registered) err = -ENOENT; netlink_unlock_table(); if (err) return err; nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL); if (nlk->groups == NULL) return -ENOMEM; nlk->ngroups = groups; return 0; } static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len) { struct sock *sk = sock->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; if (nlk->groups == NULL) { err = netlink_alloc_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, 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 (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); struct sockaddr_nl *nladdr=(struct sockaddr_nl *)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) { if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { sk->sk_err = ENOBUFS; sk->sk_error_report(sk); } } static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) { int protocol = ssk->sk_protocol; struct sock *sock; struct netlink_sock *nlk; sock = netlink_lookup(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 ((nlk->pid == 0 && !nlk->data_ready) || (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_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, int nonblock, 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 || nlk_sk(ssk)->pid == 0) 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; } int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol) { int len = skb->len; skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, len); sock_put(sk); return len; } void netlink_detachskb(struct sock *sk, struct sk_buff *skb) { kfree_skb(skb); sock_put(sk); } static inline 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; } 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); } err = netlink_attachskb(sk, skb, nonblock, timeo, ssk); if (err == 1) goto retry; if (err) return err; return netlink_sendskb(sk, skb, ssk->sk_protocol); } int netlink_has_listeners(struct sock *sk, unsigned int group) { int res = 0; BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET)); if (group - 1 < nl_table[sk->sk_protocol].groups) res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners); return res; } EXPORT_SYMBOL_GPL(netlink_has_listeners); static __inline__ 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); skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, skb->len); return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf; } return -1; } struct netlink_broadcast_data { struct sock *exclude_sk; u32 pid; u32 group; int failure; int congested; int delivered; gfp_t allocation; struct sk_buff *skb, *skb2; }; static inline 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 (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; } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { netlink_overrun(sk); } else { p->congested |= val; p->delivered = 1; p->skb2 = NULL; } sock_put(sk); out: return 0; } int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, u32 group, gfp_t allocation) { struct netlink_broadcast_data info; struct hlist_node *node; struct sock *sk; skb = netlink_trim(skb, allocation); info.exclude_sk = ssk; info.pid = pid; info.group = group; info.failure = 0; info.congested = 0; info.delivered = 0; info.allocation = allocation; info.skb = skb; info.skb2 = NULL; /* 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); kfree_skb(skb); netlink_unlock_table(); if (info.skb2) kfree_skb(info.skb2); if (info.delivered) { if (info.congested && (allocation & __GFP_WAIT)) yield(); return 0; } if (info.failure) return -ENOBUFS; return -ESRCH; } struct netlink_set_err_data { struct sock *exclude_sk; u32 pid; u32 group; int code; }; static inline int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) { struct netlink_sock *nlk = nlk_sk(sk); if (sk == p->exclude_sk) goto out; if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || !test_bit(p->group - 1, nlk->groups)) goto out; sk->sk_err = p->code; sk->sk_error_report(sk); out: return 0; } void 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; info.exclude_sk = ssk; info.pid = pid; info.group = group; info.code = code; read_lock(&nl_table_lock); sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) do_one_set_err(sk, &info); read_unlock(&nl_table_lock); } static int netlink_setsockopt(struct socket *sock, int level, int optname, char __user *optval, int optlen) { struct sock *sk = sock->sk; struct netlink_sock *nlk = nlk_sk(sk); int val = 0, err; if (level != SOL_NETLINK) return -ENOPROTOOPT; if (optlen >= sizeof(int) && get_user(val, (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: { unsigned int subscriptions; int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0; if (!netlink_capable(sock, NL_NONROOT_RECV)) return -EPERM; if (nlk->groups == NULL) { err = netlink_alloc_groups(sk); if (err) return err; } if (!val || val - 1 >= nlk->ngroups) return -EINVAL; netlink_table_grab(); old = test_bit(val - 1, nlk->groups); subscriptions = nlk->subscriptions - old + new; if (new) __set_bit(val - 1, nlk->groups); else __clear_bit(val - 1, nlk->groups); netlink_update_subscriptions(sk, subscriptions); netlink_update_listeners(sk); netlink_table_ungrab(); 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; 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 inline 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_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); if (err < 0) return err; if (msg->msg_namelen) { if (addr->nl_family != AF_NETLINK) return -EINVAL; dst_pid = addr->nl_pid; dst_group = ffs(addr->nl_groups); if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND)) return -EPERM; } 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; NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context); selinux_get_task_sid(current, &(NETLINK_CB(skb).sid)); memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); /* What can I do? Netlink is asynchronous, so that we will have to save current capabilities to check them, when this message will be delivered to corresponding kernel module. --ANK (980802) */ 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: 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; int err; if (flags&MSG_OOB) return -EOPNOTSUPP; copied = 0; skb = skb_recv_datagram(sk,flags,noblock,&err); if (skb==NULL) goto out; msg->msg_namelen = 0; copied = skb->len; if (len < copied) { msg->msg_flags |= MSG_TRUNC; copied = len; } skb->h.raw = skb->data; err = skb_copy_datagram_iovec(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); skb_free_datagram(sk, skb); if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) netlink_dump(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) { struct netlink_sock *nlk = nlk_sk(sk); if (nlk->data_ready) nlk->data_ready(sk, len); netlink_rcv_wake(sk); } /* * 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(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module) { struct socket *sock; struct sock *sk; struct netlink_sock *nlk; unsigned long *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; if (__netlink_create(sock, unit) < 0) goto out_sock_release; if (groups < 32) groups = 32; listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL); if (!listeners) goto out_sock_release; sk = sock->sk; sk->sk_data_ready = netlink_data_ready; if (input) nlk_sk(sk)->data_ready = input; if (netlink_insert(sk, 0)) goto out_sock_release; nlk = nlk_sk(sk); nlk->flags |= NETLINK_KERNEL_SOCKET; netlink_table_grab(); nl_table[unit].groups = groups; nl_table[unit].listeners = listeners; nl_table[unit].module = module; nl_table[unit].registered = 1; netlink_table_ungrab(); return sk; out_sock_release: kfree(listeners); sock_release(sock); return NULL; } void netlink_set_nonroot(int protocol, unsigned int flags) { if ((unsigned int)protocol < MAX_LINKS) nl_table[protocol].nl_nonroot = flags; } static void netlink_destroy_callback(struct netlink_callback *cb) { if (cb->skb) kfree_skb(cb->skb); kfree(cb); } /* * 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; struct nlmsghdr *nlh; int len, err = -ENOBUFS; skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); if (!skb) goto errout; spin_lock(&nlk->cb_lock); cb = nlk->cb; if (cb == NULL) { err = -EINVAL; goto errout_skb; } len = cb->dump(skb, cb); if (len > 0) { spin_unlock(&nlk->cb_lock); skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, len); return 0; } nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); if (!nlh) goto errout_skb; memcpy(nlmsg_data(nlh), &len, sizeof(len)); skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, skb->len); if (cb->done) cb->done(cb); nlk->cb = NULL; spin_unlock(&nlk->cb_lock); netlink_destroy_callback(cb); return 0; errout_skb: spin_unlock(&nlk->cb_lock); kfree_skb(skb); errout: return err; } int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, struct nlmsghdr *nlh, int (*dump)(struct sk_buff *skb, struct netlink_callback*), int (*done)(struct netlink_callback*)) { struct netlink_callback *cb; struct sock *sk; struct netlink_sock *nlk; cb = kzalloc(sizeof(*cb), GFP_KERNEL); if (cb == NULL) return -ENOBUFS; cb->dump = dump; cb->done = done; cb->nlh = nlh; atomic_inc(&skb->users); cb->skb = skb; sk = netlink_lookup(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... */ spin_lock(&nlk->cb_lock); if (nlk->cb) { spin_unlock(&nlk->cb_lock); netlink_destroy_callback(cb); sock_put(sk); return -EBUSY; } nlk->cb = cb; spin_unlock(&nlk->cb_lock); netlink_dump(sk); sock_put(sk); return 0; } 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(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, sizeof(struct nlmsgerr), 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); } static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, struct nlmsghdr *, int *)) { struct nlmsghdr *nlh; int err; while (skb->len >= nlmsg_total_size(0)) { nlh = (struct nlmsghdr *) skb->data; if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) return 0; if (cb(skb, nlh, &err) < 0) { /* Not an error, but we have to interrupt processing * here. Note: that in this case we do not pull * message from skb, it will be processed later. */ if (err == 0) return -1; netlink_ack(skb, nlh, err); } else if (nlh->nlmsg_flags & NLM_F_ACK) netlink_ack(skb, nlh, 0); netlink_queue_skip(nlh, skb); } return 0; } /** * nelink_run_queue - Process netlink receive queue. * @sk: Netlink socket containing the queue * @qlen: Place to store queue length upon entry * @cb: Callback function invoked for each netlink message found * * Processes as much as there was in the queue upon entry and invokes * a callback function for each netlink message found. The callback * function may refuse a message by returning a negative error code * but setting the error pointer to 0 in which case this function * returns with a qlen != 0. * * qlen must be initialized to 0 before the initial entry, afterwards * the function may be called repeatedly until qlen reaches 0. */ void netlink_run_queue(struct sock *sk, unsigned int *qlen, int (*cb)(struct sk_buff *, struct nlmsghdr *, int *)) { struct sk_buff *skb; if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue)) *qlen = skb_queue_len(&sk->sk_receive_queue); for (; *qlen; (*qlen)--) { skb = skb_dequeue(&sk->sk_receive_queue); if (netlink_rcv_skb(skb, cb)) { if (skb->len) skb_queue_head(&sk->sk_receive_queue, skb); else { kfree_skb(skb); (*qlen)--; } break; } kfree_skb(skb); } } /** * netlink_queue_skip - Skip netlink message while processing queue. * @nlh: Netlink message to be skipped * @skb: Socket buffer containing the netlink messages. * * Pulls the given netlink message off the socket buffer so the next * call to netlink_queue_run() will not reconsider the message. */ void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb) { int msglen = NLMSG_ALIGN(nlh->nlmsg_len); if (msglen > skb->len) msglen = skb->len; skb_pull(skb, msglen); } /** * 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 */ nlmsg_multicast(sk, skb, exclude_pid, group, flags); } if (report) err = nlmsg_unicast(sk, skb, pid); return err; } #ifdef CONFIG_PROC_FS struct nl_seq_iter { 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 (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) { 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); s = sk_next(v); if (s) return s; iter = seq->private; 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]); 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) { 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\n"); else { struct sock *s = v; struct netlink_sock *nlk = nlk_sk(s); seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n", s, s->sk_protocol, nlk->pid, nlk->groups ? (u32)nlk->groups[0] : 0, atomic_read(&s->sk_rmem_alloc), atomic_read(&s->sk_wmem_alloc), nlk->cb, atomic_read(&s->sk_refcnt) ); } return 0; } static 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) { struct seq_file *seq; struct nl_seq_iter *iter; int err; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; err = seq_open(file, &netlink_seq_ops); if (err) { kfree(iter); return err; } seq = file->private_data; seq->private = iter; return 0; } static struct file_operations netlink_seq_fops = { .owner = THIS_MODULE, .open = netlink_seq_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; #endif int netlink_register_notifier(struct notifier_block *nb) { return atomic_notifier_chain_register(&netlink_chain, nb); } int netlink_unregister_notifier(struct notifier_block *nb) { return atomic_notifier_chain_unregister(&netlink_chain, nb); } 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 struct net_proto_family netlink_family_ops = { .family = PF_NETLINK, .create = netlink_create, .owner = THIS_MODULE, /* for consistency 8) */ }; static int __init netlink_proto_init(void) { struct sk_buff *dummy_skb; int i; unsigned long max; 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 (num_physpages >= (128 * 1024)) max = num_physpages >> (21 - PAGE_SHIFT); else max = num_physpages >> (23 - PAGE_SHIFT); order = get_bitmask_order(max) - 1 + PAGE_SHIFT; max = (1UL << order) / sizeof(struct hlist_head); order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1; for (i = 0; i < MAX_LINKS; i++) { struct nl_pid_hash *hash = &nl_table[i].hash; hash->table = nl_pid_hash_alloc(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; } memset(hash->table, 0, 1 * sizeof(*hash->table)); hash->max_shift = order; hash->shift = 0; hash->mask = 0; hash->rehash_time = jiffies; } sock_register(&netlink_family_ops); #ifdef CONFIG_PROC_FS proc_net_fops_create("netlink", 0, &netlink_seq_fops); #endif /* 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); EXPORT_SYMBOL(netlink_ack); EXPORT_SYMBOL(netlink_run_queue); EXPORT_SYMBOL(netlink_queue_skip); EXPORT_SYMBOL(netlink_broadcast); EXPORT_SYMBOL(netlink_dump_start); EXPORT_SYMBOL(netlink_kernel_create); EXPORT_SYMBOL(netlink_register_notifier); EXPORT_SYMBOL(netlink_set_err); EXPORT_SYMBOL(netlink_set_nonroot); EXPORT_SYMBOL(netlink_unicast); EXPORT_SYMBOL(netlink_unregister_notifier); EXPORT_SYMBOL(nlmsg_notify);