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authorJohn Lo <loj@cisco.com>2019-04-01 11:30:07 -0400
committerJohn Lo <loj@cisco.com>2019-04-01 11:30:07 -0400
commitf545caada9fe764e296a4ff59bf3d333ce3cb08a (patch)
treec473dfc33b064082e9d90cccffd4cc5bd47094d3 /src/vlib
parentac3b1139578b544cae3884548f455a1e7b4910f4 (diff)
Enhance vlib_buffer_clone to change headroom space for packet
Add function vlib_buffer_clone_at_offset() so that the cloned packets' 1st buffer will have the original packet header copied at the specified offset (instead of current_data). This can be used to increase headroom in the cloned packet to allow large header encaps in case the stdandard 128B predata is not enough. The original vlib_buffer_clone() still works the same as before. Change-Id: I3b50c8ad7e3952568bc141710567c99a3dacddce Signed-off-by: John Lo <loj@cisco.com>
Diffstat (limited to 'src/vlib')
-rw-r--r--src/vlib/buffer_funcs.h73
1 files changed, 66 insertions, 7 deletions
diff --git a/src/vlib/buffer_funcs.h b/src/vlib/buffer_funcs.h
index e7fd6126d47..e9d0704c837 100644
--- a/src/vlib/buffer_funcs.h
+++ b/src/vlib/buffer_funcs.h
@@ -1033,6 +1033,31 @@ vlib_buffer_copy_no_chain (vlib_main_t * vm, vlib_buffer_t * b, u32 * di)
return d;
}
+/* \brief Move packet from current position to offset position in buffer.
+ Only work for small packet using one buffer with room to fit the move
+ @param vm - (vlib_main_t *) vlib main data structure pointer
+ @param b - (vlib_buffer_t *) pointer to buffer
+ @param offset - (i16) position to move the packet in buffer
+ */
+always_inline void
+vlib_buffer_move (vlib_main_t * vm, vlib_buffer_t * b, i16 offset)
+{
+ ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
+ ASSERT (offset + VLIB_BUFFER_PRE_DATA_SIZE >= 0);
+ ASSERT (offset + b->current_length <
+ vlib_buffer_get_default_data_size (vm));
+
+ u8 *source = vlib_buffer_get_current (b);
+ b->current_data = offset;
+ u8 *destination = vlib_buffer_get_current (b);
+ u16 length = b->current_length;
+
+ if (source + length <= destination) /* no overlap */
+ clib_memcpy_fast (destination, source, length);
+ else
+ memmove (destination, source, length);
+}
+
/** \brief Create a maximum of 256 clones of buffer and store them
in the supplied array
@@ -1042,12 +1067,14 @@ vlib_buffer_copy_no_chain (vlib_main_t * vm, vlib_buffer_t * b, u32 * di)
@param n_buffers - (u16) number of buffer clones requested (<=256)
@param head_end_offset - (u16) offset relative to current position
where packet head ends
+ @param offset - (i16) copy packet head at current position if 0,
+ else at offset position to change headroom space as specified
@return - (u16) number of buffers actually cloned, may be
less than the number requested or zero
*/
always_inline u16
vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
- u16 n_buffers, u16 head_end_offset)
+ u16 n_buffers, u16 head_end_offset, i16 offset)
{
u16 i;
vlib_buffer_t *s = vlib_get_buffer (vm, src_buffer);
@@ -1055,10 +1082,16 @@ vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
ASSERT (s->ref_count == 1);
ASSERT (n_buffers);
ASSERT (n_buffers <= 256);
+ ASSERT (offset + VLIB_BUFFER_PRE_DATA_SIZE >= 0);
+ ASSERT ((offset + head_end_offset) <
+ vlib_buffer_get_default_data_size (vm));
if (s->current_length <= head_end_offset + CLIB_CACHE_LINE_BYTES * 2)
{
buffers[0] = src_buffer;
+ if (offset)
+ vlib_buffer_move (vm, s, offset);
+
for (i = 1; i < n_buffers; i++)
{
vlib_buffer_t *d;
@@ -1071,7 +1104,7 @@ vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
return n_buffers;
}
- if (PREDICT_FALSE (n_buffers == 1))
+ if (PREDICT_FALSE ((n_buffers == 1) && (offset == 0)))
{
buffers[0] = src_buffer;
return 1;
@@ -1083,7 +1116,11 @@ vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
for (i = 0; i < n_buffers; i++)
{
vlib_buffer_t *d = vlib_get_buffer (vm, buffers[i]);
- d->current_data = s->current_data;
+ if (offset)
+ d->current_data = offset;
+ else
+ d->current_data = s->current_data;
+
d->current_length = head_end_offset;
ASSERT (d->buffer_pool_index == s->buffer_pool_index);
@@ -1122,12 +1159,14 @@ vlib_buffer_clone_256 (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
@param n_buffers - (u16) number of buffer clones requested (<=256)
@param head_end_offset - (u16) offset relative to current position
where packet head ends
+ @param offset - (i16) copy packet head at current position if 0,
+ else at offset position to change headroom space as specified
@return - (u16) number of buffers actually cloned, may be
less than the number requested or zero
*/
always_inline u16
-vlib_buffer_clone (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
- u16 n_buffers, u16 head_end_offset)
+vlib_buffer_clone_at_offset (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
+ u16 n_buffers, u16 head_end_offset, i16 offset)
{
vlib_buffer_t *s = vlib_get_buffer (vm, src_buffer);
u16 n_cloned = 0;
@@ -1139,16 +1178,36 @@ vlib_buffer_clone (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
n_cloned += vlib_buffer_clone_256 (vm,
vlib_get_buffer_index (vm, copy),
(buffers + n_cloned),
- 256, head_end_offset);
+ 256, head_end_offset, offset);
n_buffers -= 256;
}
n_cloned += vlib_buffer_clone_256 (vm, src_buffer,
buffers + n_cloned,
- n_buffers, head_end_offset);
+ n_buffers, head_end_offset, offset);
return n_cloned;
}
+/** \brief Create multiple clones of buffer and store them
+ in the supplied array
+
+ @param vm - (vlib_main_t *) vlib main data structure pointer
+ @param src_buffer - (u32) source buffer index
+ @param buffers - (u32 * ) buffer index array
+ @param n_buffers - (u16) number of buffer clones requested (<=256)
+ @param head_end_offset - (u16) offset relative to current position
+ where packet head ends
+ @return - (u16) number of buffers actually cloned, may be
+ less than the number requested or zero
+*/
+always_inline u16
+vlib_buffer_clone (vlib_main_t * vm, u32 src_buffer, u32 * buffers,
+ u16 n_buffers, u16 head_end_offset)
+{
+ return vlib_buffer_clone_at_offset (vm, src_buffer, buffers, n_buffers,
+ head_end_offset, 0);
+}
+
/** \brief Attach cloned tail to the buffer
@param vm - (vlib_main_t *) vlib main data structure pointer