There is an option for recording RSS hash with packets in the
pcapng standard. This implements this for all received packets.
There is a corner case that can not be addressed with current
DPDK API's. If using rte_flow() and some hardware it is possible
to write a flow rule that uses another hash function like XOR.
But there is no API that records this, or provides the algorithm
info on a per-packet basis.
The current version of wireshark does not display the recorded
hash option. But if we build it they will come.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
lib/pcapng/rte_pcapng.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/lib/pcapng/rte_pcapng.c b/lib/pcapng/rte_pcapng.c
index 06ad712bd1eb..f7df3ddd64e8 100644
--- a/lib/pcapng/rte_pcapng.c
+++ b/lib/pcapng/rte_pcapng.c
@@ -4,6 +4,7 @@
#include <errno.h>
#include <net/if.h>
+#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -453,9 +454,10 @@ rte_pcapng_copy(uint16_t port_id, uint32_t queue,
struct pcapng_enhance_packet_block *epb;
uint32_t orig_len, data_len, padding, flags;
struct pcapng_option *opt;
- const uint16_t optlen = pcapng_optlen(sizeof(flags)) +
pcapng_optlen(sizeof(queue));
+ uint16_t optlen;
struct rte_mbuf *mc;
uint64_t ns;
+ bool rss_hash;
#ifdef RTE_LIBRTE_ETHDEV_DEBUG
RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, NULL);
@@ -488,6 +490,10 @@ rte_pcapng_copy(uint16_t port_id, uint32_t queue,
goto fail;
}
+ /* record HASH on incoming packets */
+ rss_hash = (direction == RTE_PCAPNG_DIRECTION_IN &&
+ (md->ol_flags & RTE_MBUF_F_RX_RSS_HASH));
+
/* pad the packet to 32 bit boundary */
data_len = rte_pktmbuf_data_len(mc);
padding = RTE_ALIGN(data_len, sizeof(uint32_t)) - data_len;
@@ -499,6 +505,11 @@ rte_pcapng_copy(uint16_t port_id, uint32_t queue,
memset(tail, 0, padding);
}
+ optlen = pcapng_optlen(sizeof(flags));
+ optlen += pcapng_optlen(sizeof(queue));
+ if (rss_hash)
+ optlen += pcapng_optlen(sizeof(uint8_t) + sizeof(uint32_t));
+
/* reserve trailing options and block length */
opt = (struct pcapng_option *)
rte_pktmbuf_append(mc, optlen + sizeof(uint32_t));
@@ -522,6 +533,20 @@ rte_pcapng_copy(uint16_t port_id, uint32_t queue,
opt = pcapng_add_option(opt, PCAPNG_EPB_QUEUE,
&queue, sizeof(queue));
+ if (rss_hash) {
+ uint8_t hash_opt[5];
+
+ /* The algorithm could be something else if
+ * using rte_flow_action_rss; but the current API does not
+ * have a way for ethdev to report this on a per-packet basis.
+ */
+ hash_opt[0] = PCAPNG_HASH_TOEPLITZ;
+
+ memcpy(&hash_opt[1], &md->hash.rss, sizeof(uint32_t));
+ opt = pcapng_add_option(opt, PCAPNG_EPB_HASH,
+ &hash_opt, sizeof(hash_opt));
+ }
+
/* Note: END_OPT necessary here. Wireshark doesn't do it. */
/* Add PCAPNG packet header */
--
2.35.1
