From 24b170aac55d16cb3ff934d2f3d7983dc11cbe12 Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Tue, 15 Aug 2017 05:33:11 -0700 Subject: Support proxy ARP on mirrored TAP interfaces When VPP has an interface whose address is also applied to a TAP interface on the host, then VPP's TAP interface will be unnumbered to the 'real' interface and do proxy ARP from the host. the curious aspect of this setup is that ARP requests from the host will come from the VPP's own address. Change-Id: Ia238790e1034ba3cd3facdab29387b65a31525f2 Signed-off-by: Neale Ranns --- src/vnet/ethernet/arp.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'src/vnet/ethernet') diff --git a/src/vnet/ethernet/arp.c b/src/vnet/ethernet/arp.c index c22be3fc809..c84ff47bc00 100644 --- a/src/vnet/ethernet/arp.c +++ b/src/vnet/ethernet/arp.c @@ -1004,7 +1004,17 @@ arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) if (FIB_ENTRY_FLAG_LOCAL & src_flags) { error0 = ETHERNET_ARP_ERROR_l3_src_address_is_local; - goto drop2; + /* + * When VPP has an interface whose address is also + * applied to a TAP interface on the host, then VPP's + * TAP interface will be unnumbered to the 'real' + * interface and do proxy ARP from the host. + * The curious aspect of this setup is that ARP requests + * from the host will come from the VPP's own address. + * So don't drop immediately here, instead go see if this + * is a proxy ARP case. + */ + goto drop1; } /* A Source must also be local to subnet of matching * interface address. */ @@ -1151,9 +1161,11 @@ arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) } } - /* We are going to reply to this request, so learn the sender */ - error0 = arp_learn (vnm, am, sw_if_index0, - &arp0->ip4_over_ethernet[1]); + /* We are going to reply to this request, so, in the absence of + errors, learn the sender */ + if (!error0) + error0 = arp_learn (vnm, am, sw_if_index0, + &arp0->ip4_over_ethernet[1]); vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, pi0, next0); -- cgit 1.2.3-korg