[NET]: Move generic skbuff stuff from XFRM code to generic code
Move generic skbuff stuff from XFRM code to generic code so that AF_RXRPC can use it too. The kdoc comments I've attached to the functions needs to be checked by whoever wrote them as I had to make some guesses about the workings of these functions. Signed-off-By: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Howells
David S. Miller
Родитель
926554c4b7
Коммит
716ea3a7aa
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@ -86,6 +86,7 @@
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*/
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struct net_device;
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struct scatterlist;
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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struct nf_conntrack {
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@ -347,6 +348,11 @@ extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
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extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
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int newheadroom, int newtailroom,
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gfp_t priority);
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extern int skb_to_sgvec(struct sk_buff *skb,
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struct scatterlist *sg, int offset,
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int len);
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extern int skb_cow_data(struct sk_buff *skb, int tailbits,
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struct sk_buff **trailer);
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extern int skb_pad(struct sk_buff *skb, int pad);
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#define dev_kfree_skb(a) kfree_skb(a)
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extern void skb_over_panic(struct sk_buff *skb, int len,
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@ -40,8 +40,6 @@ struct esp_data
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} auth;
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};
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extern int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len);
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extern int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
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extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
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static inline int esp_mac_digest(struct esp_data *esp, struct sk_buff *skb,
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@ -55,6 +55,7 @@
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#include <linux/cache.h>
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#include <linux/rtnetlink.h>
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#include <linux/init.h>
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#include <linux/scatterlist.h>
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#include <net/protocol.h>
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#include <net/dst.h>
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@ -2002,6 +2003,190 @@ void __init skb_init(void)
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NULL, NULL);
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}
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/**
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* skb_to_sgvec - Fill a scatter-gather list from a socket buffer
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* @skb: Socket buffer containing the buffers to be mapped
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* @sg: The scatter-gather list to map into
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* @offset: The offset into the buffer's contents to start mapping
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* @len: Length of buffer space to be mapped
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*
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* Fill the specified scatter-gather list with mappings/pointers into a
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* region of the buffer space attached to a socket buffer.
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*/
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int
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skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
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{
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int start = skb_headlen(skb);
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int i, copy = start - offset;
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int elt = 0;
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if (copy > 0) {
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if (copy > len)
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copy = len;
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sg[elt].page = virt_to_page(skb->data + offset);
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sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
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sg[elt].length = copy;
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elt++;
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if ((len -= copy) == 0)
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return elt;
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offset += copy;
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}
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for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + skb_shinfo(skb)->frags[i].size;
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if ((copy = end - offset) > 0) {
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skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
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if (copy > len)
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copy = len;
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sg[elt].page = frag->page;
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sg[elt].offset = frag->page_offset+offset-start;
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sg[elt].length = copy;
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elt++;
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if (!(len -= copy))
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return elt;
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offset += copy;
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}
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start = end;
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}
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if (skb_shinfo(skb)->frag_list) {
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struct sk_buff *list = skb_shinfo(skb)->frag_list;
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for (; list; list = list->next) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + list->len;
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if ((copy = end - offset) > 0) {
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if (copy > len)
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copy = len;
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elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
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if ((len -= copy) == 0)
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return elt;
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offset += copy;
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}
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start = end;
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}
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}
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BUG_ON(len);
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return elt;
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}
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/**
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* skb_cow_data - Check that a socket buffer's data buffers are writable
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* @skb: The socket buffer to check.
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* @tailbits: Amount of trailing space to be added
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* @trailer: Returned pointer to the skb where the @tailbits space begins
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*
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* Make sure that the data buffers attached to a socket buffer are
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* writable. If they are not, private copies are made of the data buffers
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* and the socket buffer is set to use these instead.
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*
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* If @tailbits is given, make sure that there is space to write @tailbits
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* bytes of data beyond current end of socket buffer. @trailer will be
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* set to point to the skb in which this space begins.
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*
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* The number of scatterlist elements required to completely map the
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* COW'd and extended socket buffer will be returned.
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*/
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int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
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{
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int copyflag;
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int elt;
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struct sk_buff *skb1, **skb_p;
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/* If skb is cloned or its head is paged, reallocate
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* head pulling out all the pages (pages are considered not writable
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* at the moment even if they are anonymous).
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*/
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if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
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__pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
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return -ENOMEM;
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/* Easy case. Most of packets will go this way. */
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if (!skb_shinfo(skb)->frag_list) {
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/* A little of trouble, not enough of space for trailer.
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* This should not happen, when stack is tuned to generate
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* good frames. OK, on miss we reallocate and reserve even more
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* space, 128 bytes is fair. */
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if (skb_tailroom(skb) < tailbits &&
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pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
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return -ENOMEM;
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/* Voila! */
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*trailer = skb;
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return 1;
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}
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/* Misery. We are in troubles, going to mincer fragments... */
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elt = 1;
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skb_p = &skb_shinfo(skb)->frag_list;
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copyflag = 0;
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while ((skb1 = *skb_p) != NULL) {
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int ntail = 0;
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/* The fragment is partially pulled by someone,
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* this can happen on input. Copy it and everything
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* after it. */
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if (skb_shared(skb1))
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copyflag = 1;
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/* If the skb is the last, worry about trailer. */
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if (skb1->next == NULL && tailbits) {
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if (skb_shinfo(skb1)->nr_frags ||
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skb_shinfo(skb1)->frag_list ||
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skb_tailroom(skb1) < tailbits)
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ntail = tailbits + 128;
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}
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if (copyflag ||
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skb_cloned(skb1) ||
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ntail ||
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skb_shinfo(skb1)->nr_frags ||
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skb_shinfo(skb1)->frag_list) {
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struct sk_buff *skb2;
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/* Fuck, we are miserable poor guys... */
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if (ntail == 0)
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skb2 = skb_copy(skb1, GFP_ATOMIC);
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else
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skb2 = skb_copy_expand(skb1,
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skb_headroom(skb1),
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ntail,
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GFP_ATOMIC);
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if (unlikely(skb2 == NULL))
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return -ENOMEM;
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if (skb1->sk)
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skb_set_owner_w(skb2, skb1->sk);
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/* Looking around. Are we still alive?
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* OK, link new skb, drop old one */
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skb2->next = skb1->next;
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*skb_p = skb2;
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kfree_skb(skb1);
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skb1 = skb2;
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}
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elt++;
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*trailer = skb1;
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skb_p = &skb1->next;
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}
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return elt;
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}
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EXPORT_SYMBOL(___pskb_trim);
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EXPORT_SYMBOL(__kfree_skb);
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EXPORT_SYMBOL(kfree_skb);
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@ -2036,3 +2221,6 @@ EXPORT_SYMBOL(skb_seq_read);
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EXPORT_SYMBOL(skb_abort_seq_read);
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EXPORT_SYMBOL(skb_find_text);
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EXPORT_SYMBOL(skb_append_datato_frags);
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EXPORT_SYMBOL_GPL(skb_to_sgvec);
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EXPORT_SYMBOL_GPL(skb_cow_data);
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@ -612,175 +612,6 @@ EXPORT_SYMBOL_GPL(skb_icv_walk);
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#if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)
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/* Looking generic it is not used in another places. */
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int
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skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
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{
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int start = skb_headlen(skb);
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int i, copy = start - offset;
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int elt = 0;
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if (copy > 0) {
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if (copy > len)
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copy = len;
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sg[elt].page = virt_to_page(skb->data + offset);
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sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
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sg[elt].length = copy;
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elt++;
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if ((len -= copy) == 0)
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return elt;
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offset += copy;
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}
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for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + skb_shinfo(skb)->frags[i].size;
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if ((copy = end - offset) > 0) {
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skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
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if (copy > len)
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copy = len;
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sg[elt].page = frag->page;
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sg[elt].offset = frag->page_offset+offset-start;
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sg[elt].length = copy;
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elt++;
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if (!(len -= copy))
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return elt;
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offset += copy;
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}
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start = end;
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}
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if (skb_shinfo(skb)->frag_list) {
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struct sk_buff *list = skb_shinfo(skb)->frag_list;
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for (; list; list = list->next) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + list->len;
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if ((copy = end - offset) > 0) {
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if (copy > len)
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copy = len;
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elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
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if ((len -= copy) == 0)
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return elt;
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offset += copy;
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}
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start = end;
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}
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}
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BUG_ON(len);
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return elt;
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}
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EXPORT_SYMBOL_GPL(skb_to_sgvec);
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/* Check that skb data bits are writable. If they are not, copy data
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* to newly created private area. If "tailbits" is given, make sure that
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* tailbits bytes beyond current end of skb are writable.
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*
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* Returns amount of elements of scatterlist to load for subsequent
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* transformations and pointer to writable trailer skb.
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*/
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int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
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{
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int copyflag;
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int elt;
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struct sk_buff *skb1, **skb_p;
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/* If skb is cloned or its head is paged, reallocate
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* head pulling out all the pages (pages are considered not writable
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* at the moment even if they are anonymous).
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*/
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if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
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__pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
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return -ENOMEM;
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/* Easy case. Most of packets will go this way. */
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if (!skb_shinfo(skb)->frag_list) {
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/* A little of trouble, not enough of space for trailer.
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* This should not happen, when stack is tuned to generate
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* good frames. OK, on miss we reallocate and reserve even more
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* space, 128 bytes is fair. */
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if (skb_tailroom(skb) < tailbits &&
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pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
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return -ENOMEM;
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/* Voila! */
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*trailer = skb;
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return 1;
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}
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/* Misery. We are in troubles, going to mincer fragments... */
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elt = 1;
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skb_p = &skb_shinfo(skb)->frag_list;
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copyflag = 0;
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while ((skb1 = *skb_p) != NULL) {
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int ntail = 0;
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/* The fragment is partially pulled by someone,
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* this can happen on input. Copy it and everything
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* after it. */
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if (skb_shared(skb1))
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copyflag = 1;
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/* If the skb is the last, worry about trailer. */
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if (skb1->next == NULL && tailbits) {
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if (skb_shinfo(skb1)->nr_frags ||
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skb_shinfo(skb1)->frag_list ||
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skb_tailroom(skb1) < tailbits)
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ntail = tailbits + 128;
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}
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if (copyflag ||
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skb_cloned(skb1) ||
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ntail ||
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skb_shinfo(skb1)->nr_frags ||
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skb_shinfo(skb1)->frag_list) {
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struct sk_buff *skb2;
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/* Fuck, we are miserable poor guys... */
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if (ntail == 0)
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skb2 = skb_copy(skb1, GFP_ATOMIC);
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else
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skb2 = skb_copy_expand(skb1,
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skb_headroom(skb1),
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ntail,
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GFP_ATOMIC);
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if (unlikely(skb2 == NULL))
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return -ENOMEM;
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if (skb1->sk)
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skb_set_owner_w(skb2, skb1->sk);
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/* Looking around. Are we still alive?
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* OK, link new skb, drop old one */
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skb2->next = skb1->next;
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*skb_p = skb2;
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kfree_skb(skb1);
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skb1 = skb2;
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}
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elt++;
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*trailer = skb1;
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skb_p = &skb1->next;
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}
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return elt;
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}
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EXPORT_SYMBOL_GPL(skb_cow_data);
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void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
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{
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if (tail != skb) {
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