net: mvpp2: prs: fix PPPoE with ipv6 packet parse

Current PPPoE+IPv6 entry is jumping to 'next-hdr'
field and not to 'DIP' field as done for IPv4.

Fixes: 3f51850 ("ethernet: Add new driver for Marvell Armada 375 network unit")
Reported-by: Liron Himi <lironh@marvell.com>
Signed-off-by: Stefan Chulski <stefanc@marvell.com>
Link: https://lore.kernel.org/r/1608230266-22111-1-git-send-email-stefanc@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: stefanchulski

drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c

@@ -1680,8 +1680,9 @@ static int mvpp2_prs_pppoe_init(struct mvpp2 *priv)
 	mvpp2_prs_sram_next_lu_set(&pe, MVPP2_PRS_LU_IP6);
 	mvpp2_prs_sram_ri_update(&pe, MVPP2_PRS_RI_L3_IP6,
 				 MVPP2_PRS_RI_L3_PROTO_MASK);
-	/* Skip eth_type + 4 bytes of IPv6 header */
-	mvpp2_prs_sram_shift_set(&pe, MVPP2_ETH_TYPE_LEN + 4,
+	/* Jump to DIP of IPV6 header */
+	mvpp2_prs_sram_shift_set(&pe, MVPP2_ETH_TYPE_LEN + 8 +
+				 MVPP2_MAX_L3_ADDR_SIZE,
 				 MVPP2_PRS_SRAM_OP_SEL_SHIFT_ADD);
 	/* Set L3 offset */
 	mvpp2_prs_sram_offset_set(&pe, MVPP2_PRS_SRAM_UDF_TYPE_L3,