[dpdk-dev] [RFC] app/testpmd: add generic swap forwarding engine

[Xiaoyu Min <jackmin@mellanox.com>]

This RFC propose a generic `swap` forwarding engine, which could be seen
as an extension of existing `macswap` but provide more flexibility.

With this generic `swap` forwarding engine, we can `swap` the source and
destination of L2/L3 address as well as the source and destination port
of L4 according to the user inputs.

This will be very helpful for developer/tester in some test scenarios.
For example, connection tracking functinality in OVS, which needs to
swap UDP ports in addition to L2/L3 addresses in order to complete one
connection.

Signed-off-by: Xiaoyu Min <jackmin@mellanox.com>
---
 app/test-pmd/parameters.c                   |  2 ++
 doc/guides/testpmd_app_ug/testpmd_funcs.rst | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
index 404dba2b20..5c9aecd6cb 100644
--- a/app/test-pmd/parameters.c
+++ b/app/test-pmd/parameters.c
@@ -147,6 +147,8 @@ usage(char* progname)
 	       "is default).\n");
 	printf("  --forward-mode=N: set forwarding mode (N: %s).\n",
 	       list_pkt_forwarding_modes());
+	printf("  --forward-mode=swap[:TYPE[,TYPE]]: set forwarding mode to swap "
+	       "(TYPE: auto (default) or mac or ip or tp).\n");
 	printf("  --rss-ip: set RSS functions to IPv4/IPv6 only .\n");
 	printf("  --rss-udp: set RSS functions to IPv4/IPv6 + UDP.\n");
 	printf("  --rxq=N: set the number of RX queues per port to N.\n");
diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
index dcee5de455..27f0600493 100644
--- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
+++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
@@ -298,7 +298,7 @@ set fwd
 Set the packet forwarding mode::
 
    testpmd> set fwd (io|mac|macswap|flowgen| \
-                     rxonly|txonly|csum|icmpecho|noisy) (""|retry)
+                     rxonly|txonly|csum|icmpecho|noisy|swap) (""|retry)
 
 ``retry`` can be specified for forwarding engines except ``rx_only``.
 
@@ -336,6 +336,19 @@ The available information categories are:
   Simulate more realistic behavior of a guest machine engaged in receiving
   and sending packets performing Virtual Network Function (VNF).
 
+* ``swap[:TYPE[,TYPE]*]``: Generic swap forwarding mode.
+ 
+  Swap the source and destination address or/and source and destination port of packet according to ``TYPE`` before forwarding them.
+  ``TYPE`` could be:
+
+  - ``auto``: swaps all supported fields (L2 to L4) if available, default.
+ 
+  - ``mac``: swaps the source address and destination address of Ethernet, as same as ``macswap``.
+ 
+  - ``ip``: swaps the source address and destination address of IP (v4 and v6).
+ 
+  - ``tp``: swaps the source port and destination port of transport layer (TCP and UDP).
+
 Example::
 
    testpmd> set fwd rxonly
-- 
2.26.0