af_xdp: change flag passed to bpf_set_link_xdp_fd

Originally XDP_FLAGS_REPLACE was passed to the function.
For kernels not defining this macro (for example 5.4) in if_link.h vpp
sets it to 0.
If kernel has this macro problem appears, replace flag requires
specifying the program to be replaced. bpf_set_link_xdp_fd wraps
around __bpf_set_link_xdp_fd_replace and passes 0 as old_fd, it leads to
an error while assessing for replacement (if 0 is passed
there is no assessing for replacement).
To address this issue no flag is passed to the function, only 0.

Type: improvement
Signed-off-by: Dastin Wilski <dastin.wilski@gmail.com>
Change-Id: I3689ce7eb8c71c699f0e589111929979c2bbe213

diff --git a/src/plugins/af_xdp/device.c b/src/plugins/af_xdp/device.c
index 87d1251..d107a39 100644 (file)
--- a/src/plugins/af_xdp/device.c
+++ b/src/plugins/af_xdp/device.c
@@ -212,10 +212,7 @@ af_xdp_load_program (af_xdp_create_if_args_t * args, af_xdp_device_t * ad)
       goto err0;
     }
 
-#ifndef XDP_FLAGS_REPLACE
-#define XDP_FLAGS_REPLACE 0
-#endif
-  if (bpf_set_link_xdp_fd (ad->linux_ifindex, fd, XDP_FLAGS_REPLACE))
+  if (bpf_set_link_xdp_fd (ad->linux_ifindex, fd, 0))
     {
       args->rv = VNET_API_ERROR_SYSCALL_ERROR_6;
       args->error =