From: Jeff Shaw <jeffrey.b.shaw@intel.com>
Date: Thu, 17 Apr 2025 22:02:20 +0000 (-0700)
Subject: memif: fix fib lookup in dma datapath
X-Git-Tag: v25.10-rc0~76
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=e22e6cbbb29d3ecb618b495a6fdeedbadfa0e81d;p=vpp.git

memif: fix fib lookup in dma datapath

Packets received using the DMA datapath use the buffer template copied
from the dma_info per-thread data. The sw_if_index[VLIB_TX] was not set
in the vlib buffer template, so subsequent FIB lookups were done using
table 0. This is incorrect if the interface is assigned to a different
table.

Fix the behavior by setting the sw_if_index[VLIB_TX] to ~0, so the FIB
knows to use the table to which the interface is assigned, which is the
same behavior as the non-DMA memif datapath.

Type: fix

Change-Id: I17bf9d21ef8a82c56ef839fbf2b611a633db7255
Signed-off-by: Jeff Shaw <jeffrey.b.shaw@intel.com>
---

diff --git a/src/plugins/memif/memif.c b/src/plugins/memif/memif.c
index c28c52f13ff..ad8512ac81e 100644
--- a/src/plugins/memif/memif.c
+++ b/src/plugins/memif/memif.c
@@ -379,6 +379,12 @@ memif_connect (memif_if_t * mif)
 				CLIB_CACHE_LINE_BYTES);
 	  vec_foreach (dma_info, mq->dma_info)
 	    {
+	      vlib_buffer_t *bt = &dma_info->data.buffer_template;
+
+	      clib_memset (bt, 0, sizeof (*bt));
+	      bt->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
+	      bt->total_length_not_including_first_buffer = 0;
+	      vnet_buffer (bt)->sw_if_index[VLIB_TX] = (u32) ~0;
 	      vec_validate_aligned (dma_info->data.desc_data,
 				    pow2_mask (max_log2_ring_sz),
 				    CLIB_CACHE_LINE_BYTES);