diff options
| -rw-r--r-- | include/uapi/linux/netlink.h | 32 | ||||
| -rw-r--r-- | net/Kconfig | 9 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 268 | ||||
| -rw-r--r-- | net/netlink/af_netlink.h | 20 |
4 files changed, 327 insertions, 2 deletions
diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 32a354f67ba..1a85940f8ab 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -1,6 +1,7 @@ #ifndef _UAPI__LINUX_NETLINK_H #define _UAPI__LINUX_NETLINK_H +#include <linux/kernel.h> #include <linux/socket.h> /* for __kernel_sa_family_t */ #include <linux/types.h> @@ -105,11 +106,42 @@ struct nlmsgerr { #define NETLINK_PKTINFO 3 #define NETLINK_BROADCAST_ERROR 4 #define NETLINK_NO_ENOBUFS 5 +#define NETLINK_RX_RING 6 +#define NETLINK_TX_RING 7 struct nl_pktinfo { __u32 group; }; +struct nl_mmap_req { + unsigned int nm_block_size; + unsigned int nm_block_nr; + unsigned int nm_frame_size; + unsigned int nm_frame_nr; +}; + +struct nl_mmap_hdr { + unsigned int nm_status; + unsigned int nm_len; + __u32 nm_group; + /* credentials */ + __u32 nm_pid; + __u32 nm_uid; + __u32 nm_gid; +}; + +enum nl_mmap_status { + NL_MMAP_STATUS_UNUSED, + NL_MMAP_STATUS_RESERVED, + NL_MMAP_STATUS_VALID, + NL_MMAP_STATUS_COPY, + NL_MMAP_STATUS_SKIP, +}; + +#define NL_MMAP_MSG_ALIGNMENT NLMSG_ALIGNTO +#define NL_MMAP_MSG_ALIGN(sz) __ALIGN_KERNEL(sz, NL_MMAP_MSG_ALIGNMENT) +#define NL_MMAP_HDRLEN NL_MMAP_MSG_ALIGN(sizeof(struct nl_mmap_hdr)) + #define NET_MAJOR 36 /* Major 36 is reserved for networking */ enum { diff --git a/net/Kconfig b/net/Kconfig index 2ddc9046868..1a2221630e6 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -23,6 +23,15 @@ menuconfig NET if NET +config NETLINK_MMAP + bool "Netlink: mmaped IO" + help + This option enables support for memory mapped netlink IO. This + reduces overhead by avoiding copying data between kernel- and + userspace. + + If unsure, say N. + config WANT_COMPAT_NETLINK_MESSAGES bool help diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 58b9025978f..1d3c7128e90 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -55,6 +55,7 @@ #include <linux/types.h> #include <linux/audit.h> #include <linux/mutex.h> +#include <linux/vmalloc.h> #include <net/net_namespace.h> #include <net/sock.h> @@ -107,6 +108,234 @@ static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask]; } +#ifdef CONFIG_NETLINK_MMAP +static __pure struct page *pgvec_to_page(const void *addr) +{ + if (is_vmalloc_addr(addr)) + return vmalloc_to_page(addr); + else + return virt_to_page(addr); +} + +static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len) +{ + unsigned int i; + + for (i = 0; i < len; i++) { + if (pg_vec[i] != NULL) { + if (is_vmalloc_addr(pg_vec[i])) + vfree(pg_vec[i]); + else + free_pages((unsigned long)pg_vec[i], order); + } + } + kfree(pg_vec); +} + +static void *alloc_one_pg_vec_page(unsigned long order) +{ + void *buffer; + gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO | + __GFP_NOWARN | __GFP_NORETRY; + + buffer = (void *)__get_free_pages(gfp_flags, order); + if (buffer != NULL) + return buffer; + + buffer = vzalloc((1 << order) * PAGE_SIZE); + if (buffer != NULL) + return buffer; + + gfp_flags &= ~__GFP_NORETRY; + return (void *)__get_free_pages(gfp_flags, order); +} + +static void **alloc_pg_vec(struct netlink_sock *nlk, + struct nl_mmap_req *req, unsigned int order) +{ + unsigned int block_nr = req->nm_block_nr; + unsigned int i; + void **pg_vec, *ptr; + + pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL); + if (pg_vec == NULL) + return NULL; + + for (i = 0; i < block_nr; i++) { + pg_vec[i] = ptr = alloc_one_pg_vec_page(order); + if (pg_vec[i] == NULL) + goto err1; + } + + return pg_vec; +err1: + free_pg_vec(pg_vec, order, block_nr); + return NULL; +} + +static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req, + bool closing, bool tx_ring) +{ + struct netlink_sock *nlk = nlk_sk(sk); + struct netlink_ring *ring; + struct sk_buff_head *queue; + void **pg_vec = NULL; + unsigned int order = 0; + int err; + + ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring; + queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue; + + if (!closing) { + if (atomic_read(&nlk->mapped)) + return -EBUSY; + if (atomic_read(&ring->pending)) + return -EBUSY; + } + + if (req->nm_block_nr) { + if (ring->pg_vec != NULL) + return -EBUSY; + + if ((int)req->nm_block_size <= 0) + return -EINVAL; + if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE)) + return -EINVAL; + if (req->nm_frame_size < NL_MMAP_HDRLEN) + return -EINVAL; + if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT)) + return -EINVAL; + + ring->frames_per_block = req->nm_block_size / + req->nm_frame_size; + if (ring->frames_per_block == 0) + return -EINVAL; + if (ring->frames_per_block * req->nm_block_nr != + req->nm_frame_nr) + return -EINVAL; + + order = get_order(req->nm_block_size); + pg_vec = alloc_pg_vec(nlk, req, order); + if (pg_vec == NULL) + return -ENOMEM; + } else { + if (req->nm_frame_nr) + return -EINVAL; + } + + err = -EBUSY; + mutex_lock(&nlk->pg_vec_lock); + if (closing || atomic_read(&nlk->mapped) == 0) { + err = 0; + spin_lock_bh(&queue->lock); + + ring->frame_max = req->nm_frame_nr - 1; + ring->head = 0; + ring->frame_size = req->nm_frame_size; + ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE; + + swap(ring->pg_vec_len, req->nm_block_nr); + swap(ring->pg_vec_order, order); + swap(ring->pg_vec, pg_vec); + + __skb_queue_purge(queue); + spin_unlock_bh(&queue->lock); + + WARN_ON(atomic_read(&nlk->mapped)); + } + mutex_unlock(&nlk->pg_vec_lock); + + if (pg_vec) + free_pg_vec(pg_vec, order, req->nm_block_nr); + return err; +} + +static void netlink_mm_open(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct socket *sock = file->private_data; + struct sock *sk = sock->sk; + + if (sk) + atomic_inc(&nlk_sk(sk)->mapped); +} + +static void netlink_mm_close(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct socket *sock = file->private_data; + struct sock *sk = sock->sk; + + if (sk) + atomic_dec(&nlk_sk(sk)->mapped); +} + +static const struct vm_operations_struct netlink_mmap_ops = { + .open = netlink_mm_open, + .close = netlink_mm_close, +}; + +static int netlink_mmap(struct file *file, struct socket *sock, + struct vm_area_struct *vma) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + struct netlink_ring *ring; + unsigned long start, size, expected; + unsigned int i; + int err = -EINVAL; + + if (vma->vm_pgoff) + return -EINVAL; + + mutex_lock(&nlk->pg_vec_lock); + + expected = 0; + for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) { + if (ring->pg_vec == NULL) + continue; + expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE; + } + + if (expected == 0) + goto out; + + size = vma->vm_end - vma->vm_start; + if (size != expected) + goto out; + + start = vma->vm_start; + for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) { + if (ring->pg_vec == NULL) + continue; + + for (i = 0; i < ring->pg_vec_len; i++) { + struct page *page; + void *kaddr = ring->pg_vec[i]; + unsigned int pg_num; + + for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) { + page = pgvec_to_page(kaddr); + err = vm_insert_page(vma, start, page); + if (err < 0) + goto out; + start += PAGE_SIZE; + kaddr += PAGE_SIZE; + } + } + } + + atomic_inc(&nlk->mapped); + vma->vm_ops = &netlink_mmap_ops; + err = 0; +out: + mutex_unlock(&nlk->pg_vec_lock); + return 0; +} +#else /* CONFIG_NETLINK_MMAP */ +#define netlink_mmap sock_no_mmap +#endif /* CONFIG_NETLINK_MMAP */ + static void netlink_destroy_callback(struct netlink_callback *cb) { kfree_skb(cb->skb); @@ -146,6 +375,18 @@ static void netlink_sock_destruct(struct sock *sk) } skb_queue_purge(&sk->sk_receive_queue); +#ifdef CONFIG_NETLINK_MMAP + if (1) { + struct nl_mmap_req req; + + memset(&req, 0, sizeof(req)); + if (nlk->rx_ring.pg_vec) + netlink_set_ring(sk, &req, true, false); + memset(&req, 0, sizeof(req)); + if (nlk->tx_ring.pg_vec) + netlink_set_ring(sk, &req, true, true); + } +#endif /* CONFIG_NETLINK_MMAP */ if (!sock_flag(sk, SOCK_DEAD)) { printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); @@ -409,6 +650,9 @@ static int __netlink_create(struct net *net, struct socket *sock, mutex_init(nlk->cb_mutex); } init_waitqueue_head(&nlk->wait); +#ifdef CONFIG_NETLINK_MMAP + mutex_init(&nlk->pg_vec_lock); +#endif sk->sk_destruct = netlink_sock_destruct; sk->sk_protocol = protocol; @@ -1211,7 +1455,8 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, if (level != SOL_NETLINK) return -ENOPROTOOPT; - if (optlen >= sizeof(int) && + if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING && + optlen >= sizeof(int) && get_user(val, (unsigned int __user *)optval)) return -EFAULT; @@ -1260,6 +1505,25 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, } err = 0; break; +#ifdef CONFIG_NETLINK_MMAP + case NETLINK_RX_RING: + case NETLINK_TX_RING: { + struct nl_mmap_req req; + + /* Rings might consume more memory than queue limits, require + * CAP_NET_ADMIN. + */ + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (optlen < sizeof(req)) + return -EINVAL; + if (copy_from_user(&req, optval, sizeof(req))) + return -EFAULT; + err = netlink_set_ring(sk, &req, false, + optname == NETLINK_TX_RING); + break; + } +#endif /* CONFIG_NETLINK_MMAP */ default: err = -ENOPROTOOPT; } @@ -2093,7 +2357,7 @@ static const struct proto_ops netlink_ops = { .getsockopt = netlink_getsockopt, .sendmsg = netlink_sendmsg, .recvmsg = netlink_recvmsg, - .mmap = sock_no_mmap, + .mmap = netlink_mmap, .sendpage = sock_no_sendpage, }; diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index d9acb2a1d85..ed8522265f4 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -6,6 +6,20 @@ #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long)) +struct netlink_ring { + void **pg_vec; + unsigned int head; + unsigned int frames_per_block; + unsigned int frame_size; + unsigned int frame_max; + + unsigned int pg_vec_order; + unsigned int pg_vec_pages; + unsigned int pg_vec_len; + + atomic_t pending; +}; + struct netlink_sock { /* struct sock has to be the first member of netlink_sock */ struct sock sk; @@ -24,6 +38,12 @@ struct netlink_sock { void (*netlink_rcv)(struct sk_buff *skb); void (*netlink_bind)(int group); struct module *module; +#ifdef CONFIG_NETLINK_MMAP + struct mutex pg_vec_lock; + struct netlink_ring rx_ring; + struct netlink_ring tx_ring; + atomic_t mapped; +#endif /* CONFIG_NETLINK_MMAP */ }; static inline struct netlink_sock *nlk_sk(struct sock *sk) |