diff options
author | 2015-08-04 12:17:53 -0700 | |
---|---|---|
committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/net/core/datagram.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/net/core/datagram.c')
-rw-r--r-- | kernel/net/core/datagram.c | 753 |
1 files changed, 753 insertions, 0 deletions
diff --git a/kernel/net/core/datagram.c b/kernel/net/core/datagram.c new file mode 100644 index 000000000..b80fb91bb --- /dev/null +++ b/kernel/net/core/datagram.c @@ -0,0 +1,753 @@ +/* + * SUCS NET3: + * + * Generic datagram handling routines. These are generic for all + * protocols. Possibly a generic IP version on top of these would + * make sense. Not tonight however 8-). + * This is used because UDP, RAW, PACKET, DDP, IPX, AX.25 and + * NetROM layer all have identical poll code and mostly + * identical recvmsg() code. So we share it here. The poll was + * shared before but buried in udp.c so I moved it. + * + * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>. (datagram_poll() from old + * udp.c code) + * + * Fixes: + * Alan Cox : NULL return from skb_peek_copy() + * understood + * Alan Cox : Rewrote skb_read_datagram to avoid the + * skb_peek_copy stuff. + * Alan Cox : Added support for SOCK_SEQPACKET. + * IPX can no longer use the SO_TYPE hack + * but AX.25 now works right, and SPX is + * feasible. + * Alan Cox : Fixed write poll of non IP protocol + * crash. + * Florian La Roche: Changed for my new skbuff handling. + * Darryl Miles : Fixed non-blocking SOCK_SEQPACKET. + * Linus Torvalds : BSD semantic fixes. + * Alan Cox : Datagram iovec handling + * Darryl Miles : Fixed non-blocking SOCK_STREAM. + * Alan Cox : POSIXisms + * Pete Wyckoff : Unconnected accept() fix. + * + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <asm/uaccess.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/rtnetlink.h> +#include <linux/poll.h> +#include <linux/highmem.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/pagemap.h> +#include <linux/uio.h> + +#include <net/protocol.h> +#include <linux/skbuff.h> + +#include <net/checksum.h> +#include <net/sock.h> +#include <net/tcp_states.h> +#include <trace/events/skb.h> +#include <net/busy_poll.h> + +/* + * Is a socket 'connection oriented' ? + */ +static inline int connection_based(struct sock *sk) +{ + return sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM; +} + +static int receiver_wake_function(wait_queue_t *wait, unsigned int mode, int sync, + void *key) +{ + unsigned long bits = (unsigned long)key; + + /* + * Avoid a wakeup if event not interesting for us + */ + if (bits && !(bits & (POLLIN | POLLERR))) + return 0; + return autoremove_wake_function(wait, mode, sync, key); +} +/* + * Wait for the last received packet to be different from skb + */ +static int wait_for_more_packets(struct sock *sk, int *err, long *timeo_p, + const struct sk_buff *skb) +{ + int error; + DEFINE_WAIT_FUNC(wait, receiver_wake_function); + + prepare_to_wait_exclusive(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + + /* Socket errors? */ + error = sock_error(sk); + if (error) + goto out_err; + + if (sk->sk_receive_queue.prev != skb) + goto out; + + /* Socket shut down? */ + if (sk->sk_shutdown & RCV_SHUTDOWN) + goto out_noerr; + + /* Sequenced packets can come disconnected. + * If so we report the problem + */ + error = -ENOTCONN; + if (connection_based(sk) && + !(sk->sk_state == TCP_ESTABLISHED || sk->sk_state == TCP_LISTEN)) + goto out_err; + + /* handle signals */ + if (signal_pending(current)) + goto interrupted; + + error = 0; + *timeo_p = schedule_timeout(*timeo_p); +out: + finish_wait(sk_sleep(sk), &wait); + return error; +interrupted: + error = sock_intr_errno(*timeo_p); +out_err: + *err = error; + goto out; +out_noerr: + *err = 0; + error = 1; + goto out; +} + +/** + * __skb_recv_datagram - Receive a datagram skbuff + * @sk: socket + * @flags: MSG_ flags + * @peeked: returns non-zero if this packet has been seen before + * @off: an offset in bytes to peek skb from. Returns an offset + * within an skb where data actually starts + * @err: error code returned + * + * Get a datagram skbuff, understands the peeking, nonblocking wakeups + * and possible races. This replaces identical code in packet, raw and + * udp, as well as the IPX AX.25 and Appletalk. It also finally fixes + * the long standing peek and read race for datagram sockets. If you + * alter this routine remember it must be re-entrant. + * + * This function will lock the socket if a skb is returned, so the caller + * needs to unlock the socket in that case (usually by calling + * skb_free_datagram) + * + * * It does not lock socket since today. This function is + * * free of race conditions. This measure should/can improve + * * significantly datagram socket latencies at high loads, + * * when data copying to user space takes lots of time. + * * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet + * * 8) Great win.) + * * --ANK (980729) + * + * The order of the tests when we find no data waiting are specified + * quite explicitly by POSIX 1003.1g, don't change them without having + * the standard around please. + */ +struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, + int *peeked, int *off, int *err) +{ + struct sk_buff *skb, *last; + long timeo; + /* + * Caller is allowed not to check sk->sk_err before skb_recv_datagram() + */ + int error = sock_error(sk); + + if (error) + goto no_packet; + + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + + do { + /* Again only user level code calls this function, so nothing + * interrupt level will suddenly eat the receive_queue. + * + * Look at current nfs client by the way... + * However, this function was correct in any case. 8) + */ + unsigned long cpu_flags; + struct sk_buff_head *queue = &sk->sk_receive_queue; + int _off = *off; + + last = (struct sk_buff *)queue; + spin_lock_irqsave(&queue->lock, cpu_flags); + skb_queue_walk(queue, skb) { + last = skb; + *peeked = skb->peeked; + if (flags & MSG_PEEK) { + if (_off >= skb->len && (skb->len || _off || + skb->peeked)) { + _off -= skb->len; + continue; + } + skb->peeked = 1; + atomic_inc(&skb->users); + } else + __skb_unlink(skb, queue); + + spin_unlock_irqrestore(&queue->lock, cpu_flags); + *off = _off; + return skb; + } + spin_unlock_irqrestore(&queue->lock, cpu_flags); + + if (sk_can_busy_loop(sk) && + sk_busy_loop(sk, flags & MSG_DONTWAIT)) + continue; + + /* User doesn't want to wait */ + error = -EAGAIN; + if (!timeo) + goto no_packet; + + } while (!wait_for_more_packets(sk, err, &timeo, last)); + + return NULL; + +no_packet: + *err = error; + return NULL; +} +EXPORT_SYMBOL(__skb_recv_datagram); + +struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags, + int noblock, int *err) +{ + int peeked, off = 0; + + return __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0), + &peeked, &off, err); +} +EXPORT_SYMBOL(skb_recv_datagram); + +void skb_free_datagram(struct sock *sk, struct sk_buff *skb) +{ + consume_skb(skb); + sk_mem_reclaim_partial(sk); +} +EXPORT_SYMBOL(skb_free_datagram); + +void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) +{ + bool slow; + + if (likely(atomic_read(&skb->users) == 1)) + smp_rmb(); + else if (likely(!atomic_dec_and_test(&skb->users))) + return; + + slow = lock_sock_fast(sk); + skb_orphan(skb); + sk_mem_reclaim_partial(sk); + unlock_sock_fast(sk, slow); + + /* skb is now orphaned, can be freed outside of locked section */ + __kfree_skb(skb); +} +EXPORT_SYMBOL(skb_free_datagram_locked); + +/** + * skb_kill_datagram - Free a datagram skbuff forcibly + * @sk: socket + * @skb: datagram skbuff + * @flags: MSG_ flags + * + * This function frees a datagram skbuff that was received by + * skb_recv_datagram. The flags argument must match the one + * used for skb_recv_datagram. + * + * If the MSG_PEEK flag is set, and the packet is still on the + * receive queue of the socket, it will be taken off the queue + * before it is freed. + * + * This function currently only disables BH when acquiring the + * sk_receive_queue lock. Therefore it must not be used in a + * context where that lock is acquired in an IRQ context. + * + * It returns 0 if the packet was removed by us. + */ + +int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags) +{ + int err = 0; + + if (flags & MSG_PEEK) { + err = -ENOENT; + spin_lock_bh(&sk->sk_receive_queue.lock); + if (skb == skb_peek(&sk->sk_receive_queue)) { + __skb_unlink(skb, &sk->sk_receive_queue); + atomic_dec(&skb->users); + err = 0; + } + spin_unlock_bh(&sk->sk_receive_queue.lock); + } + + kfree_skb(skb); + atomic_inc(&sk->sk_drops); + sk_mem_reclaim_partial(sk); + + return err; +} +EXPORT_SYMBOL(skb_kill_datagram); + +/** + * skb_copy_datagram_iter - Copy a datagram to an iovec iterator. + * @skb: buffer to copy + * @offset: offset in the buffer to start copying from + * @to: iovec iterator to copy to + * @len: amount of data to copy from buffer to iovec + */ +int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, + struct iov_iter *to, int len) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + + trace_skb_copy_datagram_iovec(skb, len); + + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + if (copy_to_iter(skb->data + offset, copy, to) != copy) + goto short_copy; + if ((len -= copy) == 0) + return 0; + offset += copy; + } + + /* Copy paged appendix. Hmm... why does this look so complicated? */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + WARN_ON(start > offset + len); + + end = start + skb_frag_size(frag); + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (copy_page_to_iter(skb_frag_page(frag), + frag->page_offset + offset - + start, copy, to) != copy) + goto short_copy; + if (!(len -= copy)) + return 0; + offset += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (skb_copy_datagram_iter(frag_iter, offset - start, + to, copy)) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + } + start = end; + } + if (!len) + return 0; + + /* This is not really a user copy fault, but rather someone + * gave us a bogus length on the skb. We should probably + * print a warning here as it may indicate a kernel bug. + */ + +fault: + return -EFAULT; + +short_copy: + if (iov_iter_count(to)) + goto fault; + + return 0; +} +EXPORT_SYMBOL(skb_copy_datagram_iter); + +/** + * skb_copy_datagram_from_iter - Copy a datagram from an iov_iter. + * @skb: buffer to copy + * @offset: offset in the buffer to start copying to + * @from: the copy source + * @len: amount of data to copy to buffer from iovec + * + * Returns 0 or -EFAULT. + */ +int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset, + struct iov_iter *from, + int len) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + if (copy_from_iter(skb->data + offset, copy, from) != copy) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + } + + /* Copy paged appendix. Hmm... why does this look so complicated? */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + WARN_ON(start > offset + len); + + end = start + skb_frag_size(frag); + if ((copy = end - offset) > 0) { + size_t copied; + + if (copy > len) + copy = len; + copied = copy_page_from_iter(skb_frag_page(frag), + frag->page_offset + offset - start, + copy, from); + if (copied != copy) + goto fault; + + if (!(len -= copy)) + return 0; + offset += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (skb_copy_datagram_from_iter(frag_iter, + offset - start, + from, copy)) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + } + start = end; + } + if (!len) + return 0; + +fault: + return -EFAULT; +} +EXPORT_SYMBOL(skb_copy_datagram_from_iter); + +/** + * zerocopy_sg_from_iter - Build a zerocopy datagram from an iov_iter + * @skb: buffer to copy + * @from: the source to copy from + * + * The function will first copy up to headlen, and then pin the userspace + * pages and build frags through them. + * + * Returns 0, -EFAULT or -EMSGSIZE. + */ +int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from) +{ + int len = iov_iter_count(from); + int copy = min_t(int, skb_headlen(skb), len); + int frag = 0; + + /* copy up to skb headlen */ + if (skb_copy_datagram_from_iter(skb, 0, from, copy)) + return -EFAULT; + + while (iov_iter_count(from)) { + struct page *pages[MAX_SKB_FRAGS]; + size_t start; + ssize_t copied; + unsigned long truesize; + int n = 0; + + if (frag == MAX_SKB_FRAGS) + return -EMSGSIZE; + + copied = iov_iter_get_pages(from, pages, ~0U, + MAX_SKB_FRAGS - frag, &start); + if (copied < 0) + return -EFAULT; + + iov_iter_advance(from, copied); + + truesize = PAGE_ALIGN(copied + start); + skb->data_len += copied; + skb->len += copied; + skb->truesize += truesize; + atomic_add(truesize, &skb->sk->sk_wmem_alloc); + while (copied) { + int size = min_t(int, copied, PAGE_SIZE - start); + skb_fill_page_desc(skb, frag++, pages[n], start, size); + start = 0; + copied -= size; + n++; + } + } + return 0; +} +EXPORT_SYMBOL(zerocopy_sg_from_iter); + +static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, + struct iov_iter *to, int len, + __wsum *csump) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + struct sk_buff *frag_iter; + int pos = 0; + int n; + + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + n = csum_and_copy_to_iter(skb->data + offset, copy, csump, to); + if (n != copy) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + pos = copy; + } + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + WARN_ON(start > offset + len); + + end = start + skb_frag_size(frag); + if ((copy = end - offset) > 0) { + __wsum csum2 = 0; + struct page *page = skb_frag_page(frag); + u8 *vaddr = kmap(page); + + if (copy > len) + copy = len; + n = csum_and_copy_to_iter(vaddr + frag->page_offset + + offset - start, copy, + &csum2, to); + kunmap(page); + if (n != copy) + goto fault; + *csump = csum_block_add(*csump, csum2, pos); + if (!(len -= copy)) + return 0; + offset += copy; + pos += copy; + } + start = end; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + if ((copy = end - offset) > 0) { + __wsum csum2 = 0; + if (copy > len) + copy = len; + if (skb_copy_and_csum_datagram(frag_iter, + offset - start, + to, copy, + &csum2)) + goto fault; + *csump = csum_block_add(*csump, csum2, pos); + if ((len -= copy) == 0) + return 0; + offset += copy; + pos += copy; + } + start = end; + } + if (!len) + return 0; + +fault: + return -EFAULT; +} + +__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len) +{ + __sum16 sum; + + sum = csum_fold(skb_checksum(skb, 0, len, skb->csum)); + if (likely(!sum)) { + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && + !skb->csum_complete_sw) + netdev_rx_csum_fault(skb->dev); + } + skb->csum_valid = !sum; + return sum; +} +EXPORT_SYMBOL(__skb_checksum_complete_head); + +__sum16 __skb_checksum_complete(struct sk_buff *skb) +{ + __wsum csum; + __sum16 sum; + + csum = skb_checksum(skb, 0, skb->len, 0); + + /* skb->csum holds pseudo checksum */ + sum = csum_fold(csum_add(skb->csum, csum)); + if (likely(!sum)) { + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && + !skb->csum_complete_sw) + netdev_rx_csum_fault(skb->dev); + } + + /* Save full packet checksum */ + skb->csum = csum; + skb->ip_summed = CHECKSUM_COMPLETE; + skb->csum_complete_sw = 1; + skb->csum_valid = !sum; + + return sum; +} +EXPORT_SYMBOL(__skb_checksum_complete); + +/** + * skb_copy_and_csum_datagram_msg - Copy and checksum skb to user iovec. + * @skb: skbuff + * @hlen: hardware length + * @msg: destination + * + * Caller _must_ check that skb will fit to this iovec. + * + * Returns: 0 - success. + * -EINVAL - checksum failure. + * -EFAULT - fault during copy. + */ +int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, + int hlen, struct msghdr *msg) +{ + __wsum csum; + int chunk = skb->len - hlen; + + if (!chunk) + return 0; + + if (msg_data_left(msg) < chunk) { + if (__skb_checksum_complete(skb)) + goto csum_error; + if (skb_copy_datagram_msg(skb, hlen, msg, chunk)) + goto fault; + } else { + csum = csum_partial(skb->data, hlen, skb->csum); + if (skb_copy_and_csum_datagram(skb, hlen, &msg->msg_iter, + chunk, &csum)) + goto fault; + if (csum_fold(csum)) + goto csum_error; + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) + netdev_rx_csum_fault(skb->dev); + } + return 0; +csum_error: + return -EINVAL; +fault: + return -EFAULT; +} +EXPORT_SYMBOL(skb_copy_and_csum_datagram_msg); + +/** + * datagram_poll - generic datagram poll + * @file: file struct + * @sock: socket + * @wait: poll table + * + * Datagram poll: Again totally generic. This also handles + * sequenced packet sockets providing the socket receive queue + * is only ever holding data ready to receive. + * + * Note: when you _don't_ use this routine for this protocol, + * and you use a different write policy from sock_writeable() + * then please supply your own write_space callback. + */ +unsigned int datagram_poll(struct file *file, struct socket *sock, + poll_table *wait) +{ + struct sock *sk = sock->sk; + unsigned int mask; + + sock_poll_wait(file, sk_sleep(sk), wait); + mask = 0; + + /* exceptional events? */ + if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) + mask |= POLLERR | + (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0); + + if (sk->sk_shutdown & RCV_SHUTDOWN) + mask |= POLLRDHUP | POLLIN | POLLRDNORM; + if (sk->sk_shutdown == SHUTDOWN_MASK) + mask |= POLLHUP; + + /* readable? */ + if (!skb_queue_empty(&sk->sk_receive_queue)) + mask |= POLLIN | POLLRDNORM; + + /* Connection-based need to check for termination and startup */ + if (connection_based(sk)) { + if (sk->sk_state == TCP_CLOSE) + mask |= POLLHUP; + /* connection hasn't started yet? */ + if (sk->sk_state == TCP_SYN_SENT) + return mask; + } + + /* writable? */ + if (sock_writeable(sk)) + mask |= POLLOUT | POLLWRNORM | POLLWRBAND; + else + set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); + + return mask; +} +EXPORT_SYMBOL(datagram_poll); |