zebra: Allow *BSD to specify a receive buffer size

End operator is reporting that they are receiving buffer overruns
when attempting to read from the kernel receive socket.  It is
possible to adjust this size to more modern levels especially
for when the system is under load.  Modify the code base
so that *BSD operators can use the zebra `-s XXX` option
to specify a read buffer.

Additionally setup the default receive buffer size on *BSD
to be 128k instead of the 8k so that FRR does not run into
this issue again.

Fixes: #10666
Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/zebra/main.c b/zebra/main.c
index 9deafb532e..7ef30d1d49 100644
--- a/zebra/main.c
+++ b/zebra/main.c
@@ -78,10 +78,12 @@ int graceful_restart;
 
 bool v6_rr_semantics = false;
 
+/* Receive buffer size for kernel control sockets */
 #ifdef HAVE_NETLINK
-/* Receive buffer size for netlink socket */
-uint32_t nl_rcvbufsize = 4194304;
-#endif /* HAVE_NETLINK */
+uint32_t rcvbufsize = 4194304;
+#else
+uint32_t rcvbufsize = 128 * 1024;
+#endif
 
 #define OPTION_V6_RR_SEMANTICS 2000
 #define OPTION_ASIC_OFFLOAD    2001
@@ -294,9 +296,9 @@ int main(int argc, char **argv)
 	frr_preinit(&zebra_di, argc, argv);
 
 	frr_opt_add(
-		"baz:e:rK:"
+		"baz:e:rK:s:"
 #ifdef HAVE_NETLINK
-		"s:n"
+		"n"
 #endif
 		,
 		longopts,
@@ -308,9 +310,11 @@ int main(int argc, char **argv)
 		"  -K, --graceful_restart   Graceful restart at the kernel level, timer in seconds for expiration\n"
 		"  -A, --asic-offload       FRR is interacting with an asic underneath the linux kernel\n"
 #ifdef HAVE_NETLINK
-		"  -n, --vrfwnetns          Use NetNS as VRF backend\n"
 		"  -s, --nl-bufsize         Set netlink receive buffer size\n"
+		"  -n, --vrfwnetns          Use NetNS as VRF backend\n"
 		"      --v6-rr-semantics    Use v6 RR semantics\n"
+#else
+		"  -s,                      Set kernel socket receive buffer size\n"
 #endif /* HAVE_NETLINK */
 	);
 
@@ -359,10 +363,10 @@ int main(int argc, char **argv)
 		case 'K':
 			graceful_restart = atoi(optarg);
 			break;
-#ifdef HAVE_NETLINK
 		case 's':
-			nl_rcvbufsize = atoi(optarg);
+			rcvbufsize = atoi(optarg);
 			break;
+#ifdef HAVE_NETLINK
 		case 'n':
 			vrf_configure_backend(VRF_BACKEND_NETNS);
 			break;