net/core/skbuff.c

101  * size, and we can differentiate heads from skb_small_head_cache
446  * skb_shared_info. @data must have been allocated from the page
624  *	@flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
634  *	Buffers may only be allocated from interrupts using a @gfp_mask of
781  *	attempt to allocate the head from a special reserved region used
1279  * Must only be called from net_ratelimit()-ed paths.
1930  *	If this function is called from an interrupt gfp_mask() must be
2029  *	If this function is called from an interrupt gfp_mask() must be
2146  *	@fclone: if true allocate the copy of the skb from the fclone
2444  *	is called from an interrupt.
2604  *	skb_pull - remove data from the start of a buffer
2608  *	This function removes data from the start of a buffer, returning
2620  *	skb_pull_data - remove data from the start of a buffer returning its
2625  *	This function removes data from the start of a buffer, returning
2644  *	skb_trim - remove end from a buffer
2648  *	Cut the length of a buffer down by removing data from the tail. If
2775  *	data from fragmented part.
2786 /* Moves tail of skb head forward, copying data from fragmented part,
2920  *	skb_copy_bits - copy bits from skb to kernel buffer
2926  *	Copy the specified number of bytes from the source skb to the
2932  *		since it is called from BPF assembly code.
3013  * Callback from splice_to_pipe(), if we need to release some pages
3116  * Map linear and fragment data from the skb to spd. It reports true if the
3168  * Map data from the skb to a pipe. Should handle both the linear part,
3332  *	skb_store_bits - store bits from kernel buffer to skb
3335  *	@from: source buffer
3338  *	Copy the specified number of bytes from the source buffer to the
3343 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
3355 		skb_copy_to_linear_data_offset(skb, offset, from, copy);
3359 		from += copy;
3381 				memcpy(vaddr + p_off, from + copied, p_len);
3388 			from += copy;
3403 					   from, copy))
3408 			from += copy;
3622  * which has been changed from the hardware checksum, for example, by
3691  *	@from: source buffer
3697 skb_zerocopy_headlen(const struct sk_buff *from)
3701 	if (!from->head_frag ||
3702 	    skb_headlen(from) < L1_CACHE_BYTES ||
3703 	    skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) {
3704 		hlen = skb_headlen(from);
3706 			hlen = from->len;
3709 	if (skb_has_frag_list(from))
3710 		hlen = from->len;
3719  *	@from: source buffer
3720  *	@len: number of bytes to copy from source buffer
3723  *	Copies up to `len` bytes from `from` to `to` by creating references
3731  *	-ENOMEM: couldn't orphan frags of @from due to lack of memory
3735 skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
3743 	BUG_ON(!from->head_frag && !hlen);
3747 		return skb_copy_bits(from, 0, skb_put(to, len), len);
3750 		ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
3755 		plen = min_t(int, skb_headlen(from), len);
3757 			page = virt_to_head_page(from->head);
3758 			offset = from->data - (unsigned char *)page_address(page);
3769 	if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
3770 		skb_tx_error(from);
3773 	skb_zerocopy_clone(to, from, GFP_ATOMIC);
3775 	for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
3780 		skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
3822  *	skb_dequeue - remove from the head of the queue
3823  *	@list: list to dequeue from
3843  *	skb_dequeue_tail - remove from the tail of the queue
3844  *	@list: list to dequeue from
3867  *	Delete all buffers on an &sk_buff list. Each buffer is removed from
3895  *	Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
3980  *	skb_unlink	-	remove a buffer from a list
3984  *	Remove a packet from a list. The list locks are taken and this
4103 /* Shifting from/to a cloned skb is a no-go.
4113  * skb_shift - Shifts paged data partially from skb to another
4115  * @skb: buffer from which the paged data comes from
4119  * the length of the skb, from skb to tgt. Returns number bytes shifted.
4132 	int from, to, merge, todo;
4143 	from = 0;
4145 	fragfrom = &skb_shinfo(skb)->frags[from];
4164 			fragfrom = &skb_shinfo(skb)->frags[from];
4174 		from++;
4179 	    (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
4185 	while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
4189 		fragfrom = &skb_shinfo(skb)->frags[from];
4195 			from++;
4226 	while (from < skb_shinfo(skb)->nr_frags)
4227 		skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
4248  * @from: lower offset of data to be read
4255 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
4258 	st->lower_offset = from;
4407  * @from: search offset
4416 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
4428 	skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
4431 	return (ret + patlen <= to - from ? ret : UINT_MAX);
4925 	 * Idea is to tranfert ownership from head_skb to last segment.
5017 	 * and should not be copied to/from user.
5102  *	skb_to_sgvec - Fill a scatter-gather list from a socket buffer
5350  * prevent the socket from being released prior to being enqueued on
5425 	/* Take a reference to prevent skb_orphan() from freeing the socket,
5520 	/* Take a reference to prevent skb_orphan() from freeing the socket,
5537  * @off: the offset from start to place the checksum.
5806  * differs from the provided skb.
5846  * differs from the provided skb.
5902  * @from: buffer to add
5906 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
5910 	int i, delta, len = from->len;
5919 	 * references if @from is cloned and !@to->pp_recycle but its
5923 	if (to->pp_recycle != from->pp_recycle)
5928 			BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
5934 	from_shinfo = skb_shinfo(from);
5937 	if (skb_zcopy(to) || skb_zcopy(from))
5940 	if (skb_headlen(from) != 0) {
5948 		if (skb_head_is_locked(from))
5951 		delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
5953 		page = virt_to_head_page(from->head);
5954 		offset = from->data - (unsigned char *)page_address(page);
5957 				   page, offset, skb_headlen(from));
5964 		delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
5974 	if (!skb_cloned(from))
5980 	if (skb_pp_frag_ref(from)) {
6001  * into/from a tunnel. Some information have to be cleared during these
6135 /* remove VLAN header from packet and update csum accordingly.
6168 /* Pop a vlan tag either from hwaccel or from payload.
6312  * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of
6543 /* carve out the first off bytes from skb when off < headlen */
6602 /* carve out the first eat bytes from skb's frag_list. May recurse into
6656 /* carve off first len bytes from skb. Split line (off) is in the
6735 /* remove len bytes from the beginning of the skb */
6746 /* Extract to_copy bytes starting at off from skb, and return this in
7079  * extracts pages from an iterator and adds them to the socket buffer if