[NET]: Move generic skbuff stuff from XFRM code to generic code
David Howells [Tue, 3 Apr 2007 03:19:53 +0000 (20:19 -0700)]
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>

include/linux/skbuff.h
include/net/esp.h
net/core/skbuff.c
net/xfrm/xfrm_algo.c

index 92969f6..9b2957d 100644 (file)
@@ -86,6 +86,7 @@
  */
 
 struct net_device;
+struct scatterlist;
 
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 struct nf_conntrack {
@@ -347,6 +348,11 @@ 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,
index 713d039..d05d8d2 100644 (file)
@@ -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,
index 331d3ef..f927b6e 100644 (file)
@@ -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>
@@ -2002,6 +2003,190 @@ 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);
@@ -2036,3 +2221,6 @@ 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);
index f373a8a..6249a94 100644 (file)
@@ -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) {