diff options
| -rw-r--r-- | include/linux/skbuff.h | 3 | ||||
| -rw-r--r-- | net/core/datagram.c | 87 |
2 files changed, 90 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 53f4f6c93356..933cfce7fcd9 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -150,6 +150,7 @@ struct net_device; struct scatterlist; struct pipe_inode_info; +struct iov_iter; #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) struct nf_conntrack { @@ -2653,6 +2654,8 @@ int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *frm, int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset, const struct iovec *to, int to_offset, int size); +int skb_copy_datagram_iter(const struct sk_buff *from, int offset, + struct iov_iter *to, int size); void skb_free_datagram(struct sock *sk, struct sk_buff *skb); void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb); int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags); diff --git a/net/core/datagram.c b/net/core/datagram.c index fdbc9a81d4c2..84d90d087a30 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -49,6 +49,7 @@ #include <linux/spinlock.h> #include <linux/slab.h> #include <linux/pagemap.h> +#include <linux/uio.h> #include <net/protocol.h> #include <linux/skbuff.h> @@ -482,6 +483,92 @@ fault: EXPORT_SYMBOL(skb_copy_datagram_const_iovec); /** + * 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_iovec - Copy a datagram from an iovec. * @skb: buffer to copy * @offset: offset in the buffer to start copying to |