diff options
| -rw-r--r-- | include/linux/skbuff.h | 3 | ||||
| -rw-r--r-- | net/core/skbuff.c | 85 | ||||
| -rw-r--r-- | net/netfilter/nfnetlink_queue_core.c | 59 |
3 files changed, 92 insertions, 55 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index bec1cc7d5e3c..7c48e2d4c72b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2345,6 +2345,9 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct pipe_inode_info *pipe, unsigned int len, unsigned int flags); void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); +unsigned int skb_zerocopy_headlen(const struct sk_buff *from); +void skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, + int len, int hlen); void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len); int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen); void skb_scrub_packet(struct sk_buff *skb, bool xnet); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 2718fed53d8c..55859cb8b83d 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2122,6 +2122,91 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, } EXPORT_SYMBOL(skb_copy_and_csum_bits); + /** + * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy() + * @from: source buffer + * + * Calculates the amount of linear headroom needed in the 'to' skb passed + * into skb_zerocopy(). + */ +unsigned int +skb_zerocopy_headlen(const struct sk_buff *from) +{ + unsigned int hlen = 0; + + if (!from->head_frag || + skb_headlen(from) < L1_CACHE_BYTES || + skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) + hlen = skb_headlen(from); + + if (skb_has_frag_list(from)) + hlen = from->len; + + return hlen; +} +EXPORT_SYMBOL_GPL(skb_zerocopy_headlen); + +/** + * skb_zerocopy - Zero copy skb to skb + * @to: destination buffer + * @source: source buffer + * @len: number of bytes to copy from source buffer + * @hlen: size of linear headroom in destination buffer + * + * Copies up to `len` bytes from `from` to `to` by creating references + * to the frags in the source buffer. + * + * The `hlen` as calculated by skb_zerocopy_headlen() specifies the + * headroom in the `to` buffer. + */ +void +skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen) +{ + int i, j = 0; + int plen = 0; /* length of skb->head fragment */ + struct page *page; + unsigned int offset; + + BUG_ON(!from->head_frag && !hlen); + + /* dont bother with small payloads */ + if (len <= skb_tailroom(to)) { + skb_copy_bits(from, 0, skb_put(to, len), len); + return; + } + + if (hlen) { + skb_copy_bits(from, 0, skb_put(to, hlen), hlen); + len -= hlen; + } else { + plen = min_t(int, skb_headlen(from), len); + if (plen) { + page = virt_to_head_page(from->head); + offset = from->data - (unsigned char *)page_address(page); + __skb_fill_page_desc(to, 0, page, offset, plen); + get_page(page); + j = 1; + len -= plen; + } + } + + to->truesize += len + plen; + to->len += len + plen; + to->data_len += len + plen; + + for (i = 0; i < skb_shinfo(from)->nr_frags; i++) { + if (!len) + break; + skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i]; + skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len); + len -= skb_shinfo(to)->frags[j].size; + skb_frag_ref(to, j); + j++; + } + skb_shinfo(to)->nr_frags = j; +} +EXPORT_SYMBOL_GPL(skb_zerocopy); + void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) { __wsum csum; diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c index 21258cf70091..615ee12647ae 100644 --- a/net/netfilter/nfnetlink_queue_core.c +++ b/net/netfilter/nfnetlink_queue_core.c @@ -235,51 +235,6 @@ nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data) spin_unlock_bh(&queue->lock); } -static void -nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen) -{ - int i, j = 0; - int plen = 0; /* length of skb->head fragment */ - struct page *page; - unsigned int offset; - - /* dont bother with small payloads */ - if (len <= skb_tailroom(to)) { - skb_copy_bits(from, 0, skb_put(to, len), len); - return; - } - - if (hlen) { - skb_copy_bits(from, 0, skb_put(to, hlen), hlen); - len -= hlen; - } else { - plen = min_t(int, skb_headlen(from), len); - if (plen) { - page = virt_to_head_page(from->head); - offset = from->data - (unsigned char *)page_address(page); - __skb_fill_page_desc(to, 0, page, offset, plen); - get_page(page); - j = 1; - len -= plen; - } - } - - to->truesize += len + plen; - to->len += len + plen; - to->data_len += len + plen; - - for (i = 0; i < skb_shinfo(from)->nr_frags; i++) { - if (!len) - break; - skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i]; - skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len); - len -= skb_shinfo(to)->frags[j].size; - skb_frag_ref(to, j); - j++; - } - skb_shinfo(to)->nr_frags = j; -} - static int nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet, bool csum_verify) @@ -304,7 +259,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, { size_t size; size_t data_len = 0, cap_len = 0; - int hlen = 0; + unsigned int hlen = 0; struct sk_buff *skb; struct nlattr *nla; struct nfqnl_msg_packet_hdr *pmsg; @@ -356,14 +311,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, if (data_len > entskb->len) data_len = entskb->len; - if (!entskb->head_frag || - skb_headlen(entskb) < L1_CACHE_BYTES || - skb_shinfo(entskb)->nr_frags >= MAX_SKB_FRAGS) - hlen = skb_headlen(entskb); - - if (skb_has_frag_list(entskb)) - hlen = entskb->len; - hlen = min_t(int, data_len, hlen); + hlen = skb_zerocopy_headlen(entskb); + hlen = min_t(unsigned int, hlen, data_len); size += sizeof(struct nlattr) + hlen; cap_len = entskb->len; break; @@ -504,7 +453,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, nla->nla_type = NFQA_PAYLOAD; nla->nla_len = nla_attr_size(data_len); - nfqnl_zcopy(skb, entskb, data_len, hlen); + skb_zerocopy(skb, entskb, data_len, hlen); } nlh->nlmsg_len = skb->len; |