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* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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#include "dynamic-string.h"
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#include "netdev-dpdk.h"
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#include "dp-packet.h"
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dp_packet_init__(struct dp_packet *b, size_t allocated, enum dp_packet_source source)
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dp_packet_set_allocated(b, allocated);
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b->l2_5_ofs = b->l3_ofs = b->l4_ofs = UINT16_MAX;
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b->md = PKT_METADATA_INITIALIZER(0);
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dp_packet_use__(struct dp_packet *b, void *base, size_t allocated,
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enum dp_packet_source source)
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dp_packet_set_base(b, base);
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dp_packet_set_data(b, base);
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dp_packet_set_size(b, 0);
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dp_packet_init__(b, allocated, source);
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/* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
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* memory starting at 'base'. 'base' should be the first byte of a region
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* obtained from malloc(). It will be freed (with free()) if 'b' is resized or
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dp_packet_use(struct dp_packet *b, void *base, size_t allocated)
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dp_packet_use__(b, base, allocated, DPBUF_MALLOC);
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/* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
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* memory starting at 'base'. 'base' should point to a buffer on the stack.
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* (Nothing actually relies on 'base' being allocated on the stack. It could
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* be static or malloc()'d memory. But stack space is the most common use
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* 'base' should be appropriately aligned. Using an array of uint32_t or
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* uint64_t for the buffer is a reasonable way to ensure appropriate alignment
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* for 32- or 64-bit data.
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* An dp_packet operation that requires reallocating data will copy the provided
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* buffer into a malloc()'d buffer. Thus, it is wise to call dp_packet_uninit()
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* on an dp_packet initialized by this function, so that if it expanded into the
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* heap, that memory is freed. */
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dp_packet_use_stub(struct dp_packet *b, void *base, size_t allocated)
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dp_packet_use__(b, base, allocated, DPBUF_STUB);
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/* Initializes 'b' as an dp_packet whose data starts at 'data' and continues for
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* 'size' bytes. This is appropriate for an dp_packet that will be used to
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* inspect existing data, without moving it around or reallocating it, and
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* generally without modifying it at all.
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* An dp_packet operation that requires reallocating data will assert-fail if this
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* function was used to initialize it. */
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dp_packet_use_const(struct dp_packet *b, const void *data, size_t size)
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dp_packet_use__(b, CONST_CAST(void *, data), size, DPBUF_STACK);
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dp_packet_set_size(b, size);
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/* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
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* memory starting at 'base'. DPDK allocated dp_packet and *data is allocated
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* from one continous memory region, so in memory data start right after
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* dp_packet. Therefore there is special method to free this type of
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* buffer. dp_packet base, data and size are initialized by dpdk rcv() so no
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* need to initialize those fields. */
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dp_packet_init_dpdk(struct dp_packet *b, size_t allocated)
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dp_packet_init__(b, allocated, DPBUF_DPDK);
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/* Initializes 'b' as an empty dp_packet with an initial capacity of 'size'
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dp_packet_init(struct dp_packet *b, size_t size)
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dp_packet_use(b, size ? xmalloc(size) : NULL, size);
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/* Frees memory that 'b' points to. */
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dp_packet_uninit(struct dp_packet *b)
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if (b->source == DPBUF_MALLOC) {
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free(dp_packet_base(b));
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} else if (b->source == DPBUF_DPDK) {
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/* If this dp_packet was allocated by DPDK it must have been
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* created as a dp_packet */
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free_dpdk_buf((struct dp_packet*) b);
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/* Creates and returns a new dp_packet with an initial capacity of 'size'
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dp_packet_new(size_t size)
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struct dp_packet *b = xmalloc(sizeof *b);
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dp_packet_init(b, size);
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/* Creates and returns a new dp_packet with an initial capacity of 'size +
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* headroom' bytes, reserving the first 'headroom' bytes as headroom. */
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dp_packet_new_with_headroom(size_t size, size_t headroom)
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struct dp_packet *b = dp_packet_new(size + headroom);
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dp_packet_reserve(b, headroom);
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/* Creates and returns a new dp_packet that initially contains a copy of the
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* 'dp_packet_size(buffer)' bytes of data starting at 'buffer->data' with no headroom or
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dp_packet_clone(const struct dp_packet *buffer)
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return dp_packet_clone_with_headroom(buffer, 0);
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/* Creates and returns a new dp_packet whose data are copied from 'buffer'. The
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* returned dp_packet will additionally have 'headroom' bytes of headroom. */
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dp_packet_clone_with_headroom(const struct dp_packet *buffer, size_t headroom)
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struct dp_packet *new_buffer;
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new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(buffer),
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dp_packet_size(buffer),
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new_buffer->l2_pad_size = buffer->l2_pad_size;
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new_buffer->l2_5_ofs = buffer->l2_5_ofs;
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new_buffer->l3_ofs = buffer->l3_ofs;
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new_buffer->l4_ofs = buffer->l4_ofs;
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new_buffer->md = buffer->md;
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/* Creates and returns a new dp_packet that initially contains a copy of the
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* 'size' bytes of data starting at 'data' with no headroom or tailroom. */
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dp_packet_clone_data(const void *data, size_t size)
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return dp_packet_clone_data_with_headroom(data, size, 0);
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/* Creates and returns a new dp_packet that initially contains 'headroom' bytes of
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* headroom followed by a copy of the 'size' bytes of data starting at
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dp_packet_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
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struct dp_packet *b = dp_packet_new_with_headroom(size, headroom);
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dp_packet_put(b, data, size);
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dp_packet_copy__(struct dp_packet *b, uint8_t *new_base,
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size_t new_headroom, size_t new_tailroom)
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const uint8_t *old_base = dp_packet_base(b);
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size_t old_headroom = dp_packet_headroom(b);
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size_t old_tailroom = dp_packet_tailroom(b);
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size_t copy_headroom = MIN(old_headroom, new_headroom);
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size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
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memcpy(&new_base[new_headroom - copy_headroom],
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&old_base[old_headroom - copy_headroom],
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copy_headroom + dp_packet_size(b) + copy_tailroom);
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/* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
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* bytes of headroom and tailroom, respectively. */
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dp_packet_resize__(struct dp_packet *b, size_t new_headroom, size_t new_tailroom)
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void *new_base, *new_data;
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size_t new_allocated;
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new_allocated = new_headroom + dp_packet_size(b) + new_tailroom;
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if (new_headroom == dp_packet_headroom(b)) {
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new_base = xrealloc(dp_packet_base(b), new_allocated);
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new_base = xmalloc(new_allocated);
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dp_packet_copy__(b, new_base, new_headroom, new_tailroom);
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free(dp_packet_base(b));
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b->source = DPBUF_MALLOC;
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new_base = xmalloc(new_allocated);
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dp_packet_copy__(b, new_base, new_headroom, new_tailroom);
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dp_packet_set_allocated(b, new_allocated);
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dp_packet_set_base(b, new_base);
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new_data = (char *) new_base + new_headroom;
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if (dp_packet_data(b) != new_data) {
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dp_packet_set_data(b, new_data);
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/* Ensures that 'b' has room for at least 'size' bytes at its tail end,
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* reallocating and copying its data if necessary. Its headroom, if any, is
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dp_packet_prealloc_tailroom(struct dp_packet *b, size_t size)
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if (size > dp_packet_tailroom(b)) {
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dp_packet_resize__(b, dp_packet_headroom(b), MAX(size, 64));
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/* Ensures that 'b' has room for at least 'size' bytes at its head,
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* reallocating and copying its data if necessary. Its tailroom, if any, is
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dp_packet_prealloc_headroom(struct dp_packet *b, size_t size)
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if (size > dp_packet_headroom(b)) {
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dp_packet_resize__(b, MAX(size, 64), dp_packet_tailroom(b));
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/* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
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* For example, a 'delta' of 1 would cause each byte of data to move one byte
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* forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
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* byte to move one byte backward (from 'p' to 'p-1'). */
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dp_packet_shift(struct dp_packet *b, int delta)
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ovs_assert(delta > 0 ? delta <= dp_packet_tailroom(b)
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: delta < 0 ? -delta <= dp_packet_headroom(b)
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char *dst = (char *) dp_packet_data(b) + delta;
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memmove(dst, dp_packet_data(b), dp_packet_size(b));
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dp_packet_set_data(b, dst);
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/* Appends 'size' bytes of data to the tail end of 'b', reallocating and
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* copying its data if necessary. Returns a pointer to the first byte of the
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* new data, which is left uninitialized. */
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dp_packet_put_uninit(struct dp_packet *b, size_t size)
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dp_packet_prealloc_tailroom(b, size);
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p = dp_packet_tail(b);
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dp_packet_set_size(b, dp_packet_size(b) + size);
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/* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
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* reallocated and copied if necessary. Returns a pointer to the first byte of
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* the data's location in the dp_packet. */
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dp_packet_put_zeros(struct dp_packet *b, size_t size)
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void *dst = dp_packet_put_uninit(b, size);
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memset(dst, 0, size);
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/* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
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* is reallocated and copied if necessary. Returns a pointer to the first
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* byte of the data's location in the dp_packet. */
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dp_packet_put(struct dp_packet *b, const void *p, size_t size)
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void *dst = dp_packet_put_uninit(b, size);
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memcpy(dst, p, size);
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/* Parses as many pairs of hex digits as possible (possibly separated by
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* spaces) from the beginning of 's', appending bytes for their values to 'b'.
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* Returns the first character of 's' that is not the first of a pair of hex
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* digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
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dp_packet_put_hex(struct dp_packet *b, const char *s, size_t *n)
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size_t initial_size = dp_packet_size(b);
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s += strspn(s, " \t\r\n");
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byte = hexits_value(s, 2, &ok);
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*n = dp_packet_size(b) - initial_size;
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return CONST_CAST(char *, s);
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dp_packet_put(b, &byte, 1);
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/* Reserves 'size' bytes of headroom so that they can be later allocated with
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* dp_packet_push_uninit() without reallocating the dp_packet. */
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dp_packet_reserve(struct dp_packet *b, size_t size)
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ovs_assert(!dp_packet_size(b));
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dp_packet_prealloc_tailroom(b, size);
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dp_packet_set_data(b, (char*)dp_packet_data(b) + size);
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/* Reserves 'headroom' bytes at the head and 'tailroom' at the end so that
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* they can be later allocated with dp_packet_push_uninit() or
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* dp_packet_put_uninit() without reallocating the dp_packet. */
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dp_packet_reserve_with_tailroom(struct dp_packet *b, size_t headroom,
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ovs_assert(!dp_packet_size(b));
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dp_packet_prealloc_tailroom(b, headroom + tailroom);
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dp_packet_set_data(b, (char*)dp_packet_data(b) + headroom);
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/* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
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* data if necessary. Returns a pointer to the first byte of the data's
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* location in the dp_packet. The new data is left uninitialized. */
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dp_packet_push_uninit(struct dp_packet *b, size_t size)
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dp_packet_prealloc_headroom(b, size);
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dp_packet_set_data(b, (char*)dp_packet_data(b) - size);
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dp_packet_set_size(b, dp_packet_size(b) + size);
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return dp_packet_data(b);
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/* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
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* copying its data if necessary. Returns a pointer to the first byte of the
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* data's location in the dp_packet. */
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dp_packet_push_zeros(struct dp_packet *b, size_t size)
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void *dst = dp_packet_push_uninit(b, size);
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memset(dst, 0, size);
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/* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
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* and copying its data if necessary. Returns a pointer to the first byte of
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* the data's location in the dp_packet. */
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dp_packet_push(struct dp_packet *b, const void *p, size_t size)
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void *dst = dp_packet_push_uninit(b, size);
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memcpy(dst, p, size);
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/* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
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* within 'b'. (If 'b' itself was dynamically allocated, e.g. with
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* dp_packet_new(), then it should still be freed with, e.g., dp_packet_delete().) */
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dp_packet_steal_data(struct dp_packet *b)
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ovs_assert(b->source != DPBUF_DPDK);
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if (b->source == DPBUF_MALLOC && dp_packet_data(b) == dp_packet_base(b)) {
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p = dp_packet_data(b);
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p = xmemdup(dp_packet_data(b), dp_packet_size(b));
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if (b->source == DPBUF_MALLOC) {
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free(dp_packet_base(b));
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dp_packet_set_base(b, NULL);
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dp_packet_set_data(b, NULL);
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/* Returns a string that describes some of 'b''s metadata plus a hex dump of up
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* to 'maxbytes' from the start of the buffer. */
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dp_packet_to_string(const struct dp_packet *b, size_t maxbytes)
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ds_put_format(&s, "size=%"PRIu32", allocated=%"PRIu32", head=%"PRIuSIZE", tail=%"PRIuSIZE"\n",
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dp_packet_size(b), dp_packet_get_allocated(b),
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dp_packet_headroom(b), dp_packet_tailroom(b));
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ds_put_hex_dump(&s, dp_packet_data(b), MIN(dp_packet_size(b), maxbytes), 0, false);
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dp_packet_adjust_layer_offset(uint16_t *offset, int increment)
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if (*offset != UINT16_MAX) {
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*offset += increment;
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/* Adjust the size of the l2_5 portion of the dp_packet, updating the l2
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* pointer and the layer offsets. The caller is responsible for
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* modifying the contents. */
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dp_packet_resize_l2_5(struct dp_packet *b, int increment)
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if (increment >= 0) {
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dp_packet_push_uninit(b, increment);
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dp_packet_pull(b, -increment);
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/* Adjust layer offsets after l2_5. */
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dp_packet_adjust_layer_offset(&b->l3_ofs, increment);
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dp_packet_adjust_layer_offset(&b->l4_ofs, increment);
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return dp_packet_data(b);
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/* Adjust the size of the l2 portion of the dp_packet, updating the l2
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* pointer and the layer offsets. The caller is responsible for
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* modifying the contents. */
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dp_packet_resize_l2(struct dp_packet *b, int increment)
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dp_packet_resize_l2_5(b, increment);
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dp_packet_adjust_layer_offset(&b->l2_5_ofs, increment);
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return dp_packet_data(b);
added
removed
lib/dp-packet.c
