lkml.org 
[lkml]   [2007]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/5] AF_RXRPC: Move generic skbuff stuff from XFRM code to generic code [try #3]
Date
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>
---
include/linux/skbuff.h | 6 ++
include/net/esp.h | 2 -
net/core/skbuff.c | 188 ++++++++++++++++++++++++++++++++++++++++++++++++
net/xfrm/xfrm_algo.c | 169 -------------------------------------------
4 files changed, 194 insertions(+), 171 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4ff3940..9e70270 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -83,6 +83,7 @@
*/

struct net_device;
+struct scatterlist;

#ifdef CONFIG_NETFILTER
struct nf_conntrack {
@@ -363,6 +364,11 @@ extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
int newheadroom, int newtailroom,
gfp_t priority);
+extern int skb_to_sgvec(struct sk_buff *skb,
+ struct scatterlist *sg, int offset,
+ int len);
+extern int skb_cow_data(struct sk_buff *skb, int tailbits,
+ struct sk_buff **trailer);
extern int skb_pad(struct sk_buff *skb, int pad);
#define dev_kfree_skb(a) kfree_skb(a)
extern void skb_over_panic(struct sk_buff *skb, int len,
diff --git a/include/net/esp.h b/include/net/esp.h
index 713d039..d05d8d2 100644
--- a/include/net/esp.h
+++ b/include/net/esp.h
@@ -40,8 +40,6 @@ struct esp_data
} auth;
};

-extern int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len);
-extern int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);

static inline int esp_mac_digest(struct esp_data *esp, struct sk_buff *skb,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 702fa8f..f3ed31b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -55,6 +55,7 @@
#include <linux/cache.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
+#include <linux/scatterlist.h>

#include <net/protocol.h>
#include <net/dst.h>
@@ -2060,6 +2061,190 @@ void __init skb_init(void)
NULL, NULL);
}

+/**
+ * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
+ * @skb: Socket buffer containing the buffers to be mapped
+ * @sg: The scatter-gather list to map into
+ * @offset: The offset into the buffer's contents to start mapping
+ * @len: Length of buffer space to be mapped
+ *
+ * Fill the specified scatter-gather list with mappings/pointers into a
+ * region of the buffer space attached to a socket buffer.
+ */
+int
+skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ int elt = 0;
+
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ sg[elt].page = virt_to_page(skb->data + offset);
+ sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
+ sg[elt].length = copy;
+ elt++;
+ if ((len -= copy) == 0)
+ return elt;
+ offset += copy;
+ }
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ if ((copy = end - offset) > 0) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (copy > len)
+ copy = len;
+ sg[elt].page = frag->page;
+ sg[elt].offset = frag->page_offset+offset-start;
+ sg[elt].length = copy;
+ elt++;
+ if (!(len -= copy))
+ return elt;
+ offset += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ for (; list; list = list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + list->len;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
+ if ((len -= copy) == 0)
+ return elt;
+ offset += copy;
+ }
+ start = end;
+ }
+ }
+ BUG_ON(len);
+ return elt;
+}
+
+/**
+ * skb_cow_data - Check that a socket buffer's data buffers are writable
+ * @skb: The socket buffer to check.
+ * @tailbits: Amount of trailing space to be added
+ * @trailer: Returned pointer to the skb where the @tailbits space begins
+ *
+ * Make sure that the data buffers attached to a socket buffer are
+ * writable. If they are not, private copies are made of the data buffers
+ * and the socket buffer is set to use these instead.
+ *
+ * If @tailbits is given, make sure that there is space to write @tailbits
+ * bytes of data beyond current end of socket buffer. @trailer will be
+ * set to point to the skb in which this space begins.
+ *
+ * The number of scatterlist elements required to completely map the
+ * COW'd and extended socket buffer will be returned.
+ */
+int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
+{
+ int copyflag;
+ int elt;
+ struct sk_buff *skb1, **skb_p;
+
+ /* If skb is cloned or its head is paged, reallocate
+ * head pulling out all the pages (pages are considered not writable
+ * at the moment even if they are anonymous).
+ */
+ if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
+ __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
+ return -ENOMEM;
+
+ /* Easy case. Most of packets will go this way. */
+ if (!skb_shinfo(skb)->frag_list) {
+ /* A little of trouble, not enough of space for trailer.
+ * This should not happen, when stack is tuned to generate
+ * good frames. OK, on miss we reallocate and reserve even more
+ * space, 128 bytes is fair. */
+
+ if (skb_tailroom(skb) < tailbits &&
+ pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
+ return -ENOMEM;
+
+ /* Voila! */
+ *trailer = skb;
+ return 1;
+ }
+
+ /* Misery. We are in troubles, going to mincer fragments... */
+
+ elt = 1;
+ skb_p = &skb_shinfo(skb)->frag_list;
+ copyflag = 0;
+
+ while ((skb1 = *skb_p) != NULL) {
+ int ntail = 0;
+
+ /* The fragment is partially pulled by someone,
+ * this can happen on input. Copy it and everything
+ * after it. */
+
+ if (skb_shared(skb1))
+ copyflag = 1;
+
+ /* If the skb is the last, worry about trailer. */
+
+ if (skb1->next == NULL && tailbits) {
+ if (skb_shinfo(skb1)->nr_frags ||
+ skb_shinfo(skb1)->frag_list ||
+ skb_tailroom(skb1) < tailbits)
+ ntail = tailbits + 128;
+ }
+
+ if (copyflag ||
+ skb_cloned(skb1) ||
+ ntail ||
+ skb_shinfo(skb1)->nr_frags ||
+ skb_shinfo(skb1)->frag_list) {
+ struct sk_buff *skb2;
+
+ /* Fuck, we are miserable poor guys... */
+ if (ntail == 0)
+ skb2 = skb_copy(skb1, GFP_ATOMIC);
+ else
+ skb2 = skb_copy_expand(skb1,
+ skb_headroom(skb1),
+ ntail,
+ GFP_ATOMIC);
+ if (unlikely(skb2 == NULL))
+ return -ENOMEM;
+
+ if (skb1->sk)
+ skb_set_owner_w(skb2, skb1->sk);
+
+ /* Looking around. Are we still alive?
+ * OK, link new skb, drop old one */
+
+ skb2->next = skb1->next;
+ *skb_p = skb2;
+ kfree_skb(skb1);
+ skb1 = skb2;
+ }
+ elt++;
+ *trailer = skb1;
+ skb_p = &skb1->next;
+ }
+
+ return elt;
+}
+
EXPORT_SYMBOL(___pskb_trim);
EXPORT_SYMBOL(__kfree_skb);
EXPORT_SYMBOL(kfree_skb);
@@ -2094,3 +2279,6 @@ EXPORT_SYMBOL(skb_seq_read);
EXPORT_SYMBOL(skb_abort_seq_read);
EXPORT_SYMBOL(skb_find_text);
EXPORT_SYMBOL(skb_append_datato_frags);
+
+EXPORT_SYMBOL_GPL(skb_to_sgvec);
+EXPORT_SYMBOL_GPL(skb_cow_data);
diff --git a/net/xfrm/xfrm_algo.c b/net/xfrm/xfrm_algo.c
index f373a8a..6249a94 100644
--- a/net/xfrm/xfrm_algo.c
+++ b/net/xfrm/xfrm_algo.c
@@ -612,175 +612,6 @@ EXPORT_SYMBOL_GPL(skb_icv_walk);

#if defined(CONFIG_INET_ESP) || defined(CONFIG_INET_ESP_MODULE) || defined(CONFIG_INET6_ESP) || defined(CONFIG_INET6_ESP_MODULE)

-/* Looking generic it is not used in another places. */
-
-int
-skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
-{
- int start = skb_headlen(skb);
- int i, copy = start - offset;
- int elt = 0;
-
- if (copy > 0) {
- if (copy > len)
- copy = len;
- sg[elt].page = virt_to_page(skb->data + offset);
- sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE;
- sg[elt].length = copy;
- elt++;
- if ((len -= copy) == 0)
- return elt;
- offset += copy;
- }
-
- for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- int end;
-
- BUG_TRAP(start <= offset + len);
-
- end = start + skb_shinfo(skb)->frags[i].size;
- if ((copy = end - offset) > 0) {
- skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-
- if (copy > len)
- copy = len;
- sg[elt].page = frag->page;
- sg[elt].offset = frag->page_offset+offset-start;
- sg[elt].length = copy;
- elt++;
- if (!(len -= copy))
- return elt;
- offset += copy;
- }
- start = end;
- }
-
- if (skb_shinfo(skb)->frag_list) {
- struct sk_buff *list = skb_shinfo(skb)->frag_list;
-
- for (; list; list = list->next) {
- int end;
-
- BUG_TRAP(start <= offset + len);
-
- end = start + list->len;
- if ((copy = end - offset) > 0) {
- if (copy > len)
- copy = len;
- elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
- if ((len -= copy) == 0)
- return elt;
- offset += copy;
- }
- start = end;
- }
- }
- BUG_ON(len);
- return elt;
-}
-EXPORT_SYMBOL_GPL(skb_to_sgvec);
-
-/* Check that skb data bits are writable. If they are not, copy data
- * to newly created private area. If "tailbits" is given, make sure that
- * tailbits bytes beyond current end of skb are writable.
- *
- * Returns amount of elements of scatterlist to load for subsequent
- * transformations and pointer to writable trailer skb.
- */
-
-int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
-{
- int copyflag;
- int elt;
- struct sk_buff *skb1, **skb_p;
-
- /* If skb is cloned or its head is paged, reallocate
- * head pulling out all the pages (pages are considered not writable
- * at the moment even if they are anonymous).
- */
- if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
- __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
- return -ENOMEM;
-
- /* Easy case. Most of packets will go this way. */
- if (!skb_shinfo(skb)->frag_list) {
- /* A little of trouble, not enough of space for trailer.
- * This should not happen, when stack is tuned to generate
- * good frames. OK, on miss we reallocate and reserve even more
- * space, 128 bytes is fair. */
-
- if (skb_tailroom(skb) < tailbits &&
- pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
- return -ENOMEM;
-
- /* Voila! */
- *trailer = skb;
- return 1;
- }
-
- /* Misery. We are in troubles, going to mincer fragments... */
-
- elt = 1;
- skb_p = &skb_shinfo(skb)->frag_list;
- copyflag = 0;
-
- while ((skb1 = *skb_p) != NULL) {
- int ntail = 0;
-
- /* The fragment is partially pulled by someone,
- * this can happen on input. Copy it and everything
- * after it. */
-
- if (skb_shared(skb1))
- copyflag = 1;
-
- /* If the skb is the last, worry about trailer. */
-
- if (skb1->next == NULL && tailbits) {
- if (skb_shinfo(skb1)->nr_frags ||
- skb_shinfo(skb1)->frag_list ||
- skb_tailroom(skb1) < tailbits)
- ntail = tailbits + 128;
- }
-
- if (copyflag ||
- skb_cloned(skb1) ||
- ntail ||
- skb_shinfo(skb1)->nr_frags ||
- skb_shinfo(skb1)->frag_list) {
- struct sk_buff *skb2;
-
- /* Fuck, we are miserable poor guys... */
- if (ntail == 0)
- skb2 = skb_copy(skb1, GFP_ATOMIC);
- else
- skb2 = skb_copy_expand(skb1,
- skb_headroom(skb1),
- ntail,
- GFP_ATOMIC);
- if (unlikely(skb2 == NULL))
- return -ENOMEM;
-
- if (skb1->sk)
- skb_set_owner_w(skb2, skb1->sk);
-
- /* Looking around. Are we still alive?
- * OK, link new skb, drop old one */
-
- skb2->next = skb1->next;
- *skb_p = skb2;
- kfree_skb(skb1);
- skb1 = skb2;
- }
- elt++;
- *trailer = skb1;
- skb_p = &skb1->next;
- }
-
- return elt;
-}
-EXPORT_SYMBOL_GPL(skb_cow_data);
-
void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
{
if (tail != skb) {
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-20 21:27    [W:0.065 / U:0.424 seconds]
©2003-2014 Jasper Spaans. Advertise on this site