nat: update ip4-udp src port for checksum == 0 pkts
Otherwise, the out2in path will discard return-path traffic with
probability 1.0.
Type: fix
Fixes: gerrit 23963 /
@@ -1118,10 +1118,11 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
{
if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
{
+ udp0->src_port = s0->out2in.port;
if (PREDICT_FALSE (udp0->checksum))
{
old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
- new_port0 = udp0->src_port = s0->out2in.port;
+ new_port0 = udp0->src_port;
sum0 = udp0->checksum;
sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address /* changed member */
);
@@ -1325,10 +1326,11 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
{
if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
{
+ udp1->src_port = s1->out2in.port;
if (PREDICT_FALSE (udp1->checksum))
{
old_port1 = vnet_buffer (b1)->ip.reass.l4_src_port;
- new_port1 = udp1->src_port = s1->out2in.port;
+ new_port1 = udp1->src_port;
sum1 = udp1->checksum;
sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t, dst_address /* changed member */
);
@@ -1567,10 +1569,11 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
{
if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
{
+ udp0->src_port = s0->out2in.port;
if (PREDICT_FALSE (udp0->checksum))
{
old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
- new_port0 = udp0->src_port = s0->out2in.port;
+ new_port0 = udp0->src_port;
sum0 = udp0->checksum;
sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address /* changed member */
);
