From f545caada9fe764e296a4ff59bf3d333ce3cb08a Mon Sep 17 00:00:00 2001 From: John Lo Date: Mon, 1 Apr 2019 11:30:07 -0400 Subject: 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 --- src/vlib/buffer_funcs.h | 73 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file 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 -- cgit 1.2.3-korg