ip: check all fib src for a connected dst entry
When looking for a connected fib entry matching the ARP destination,
there can be other DPO interposed prior to the connected one.
Type: fix
Change-Id: I9b4ab387fb08acf9879d5fda3791e6572a099492
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vnet/ethernet/arp.c b/src/vnet/ethernet/arp.c
index 201bec4..b62dc4e 100644
--- a/src/vnet/ethernet/arp.c
+++ b/src/vnet/ethernet/arp.c
@@ -1143,6 +1143,38 @@
return (next0);
}
+enum arp_dst_fib_type
+{
+ ARP_DST_FIB_NONE,
+ ARP_DST_FIB_ADJ,
+ ARP_DST_FIB_CONN
+};
+
+/*
+ * we're looking for FIB sources that indicate the destination
+ * is attached. There may be interposed DPO prior to the one
+ * we are looking for
+ */
+static enum arp_dst_fib_type
+arp_dst_fib_check (const fib_node_index_t fei, fib_entry_flag_t * flags)
+{
+ const fib_entry_t *entry = fib_entry_get (fei);
+ const fib_entry_src_t *entry_src;
+ fib_source_t src;
+ /* *INDENT-OFF* */
+ FOR_EACH_SRC_ADDED(entry, entry_src, src,
+ ({
+ *flags = fib_entry_get_flags_for_source (fei, src);
+ if (fib_entry_is_sourced (fei, FIB_SOURCE_ADJ))
+ return ARP_DST_FIB_ADJ;
+ else if (FIB_ENTRY_FLAG_CONNECTED & *flags)
+ return ARP_DST_FIB_CONN;
+ }))
+ /* *INDENT-ON* */
+
+ return ARP_DST_FIB_NONE;
+}
+
static uword
arp_reply (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
{
@@ -1173,7 +1205,7 @@
ethernet_header_t *eth_rx;
const ip4_address_t *if_addr0;
u32 pi0, error0, next0, sw_if_index0, conn_sw_if_index0, fib_index0;
- u8 dst_is_local0, is_unnum0, is_vrrp_reply0;
+ u8 dst_is_local0, is_vrrp_reply0;
fib_node_index_t dst_fei, src_fei;
const fib_prefix_t *pfx0;
fib_entry_flag_t src_flags, dst_flags;
@@ -1202,15 +1234,6 @@
goto drop;
}
- dst_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
- &arp0->ip4_over_ethernet[1].ip4,
- 32);
- dst_flags = fib_entry_get_flags (dst_fei);
-
- conn_sw_if_index0 = fib_entry_get_resolving_interface (dst_fei);
-
- /* Honor unnumbered interface, if any */
- is_unnum0 = sw_if_index0 != conn_sw_if_index0;
{
/*
@@ -1313,8 +1336,12 @@
}
}
- if (fib_entry_is_sourced (dst_fei, FIB_SOURCE_ADJ))
+ dst_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
+ &arp0->ip4_over_ethernet[1].ip4,
+ 32);
+ switch (arp_dst_fib_check (dst_fei, &dst_flags))
{
+ case ARP_DST_FIB_ADJ:
/*
* We matched an adj-fib on ths source subnet (a /32 previously
* added as a result of ARP). If this request is a gratuitous
@@ -1328,23 +1355,15 @@
error0 = arp_learn (vnm, am, sw_if_index0,
&arp0->ip4_over_ethernet[0]);
goto drop;
- }
- else if (!(FIB_ENTRY_FLAG_CONNECTED & dst_flags))
- {
+ case ARP_DST_FIB_CONN:
+ /* destination is connected, continue to process */
+ break;
+ case ARP_DST_FIB_NONE:
+ /* destination is not connected, stop here */
error0 = ETHERNET_ARP_ERROR_l3_dst_address_not_local;
goto next_feature;
}
- if (sw_if_index0 != fib_entry_get_resolving_interface (src_fei))
- {
- /*
- * The interface the ARP was received on is not the interface
- * on which the covering prefix is configured. Maybe this is a
- * case for unnumbered.
- */
- is_unnum0 = 1;
- }
-
dst_is_local0 = (FIB_ENTRY_FLAG_LOCAL & dst_flags);
pfx0 = fib_entry_get_prefix (dst_fei);
if_addr0 = &pfx0->fp_addr.ip4;
@@ -1390,8 +1409,17 @@
{
goto next_feature;
}
- if (is_unnum0)
+
+ /* Honor unnumbered interface, if any */
+ conn_sw_if_index0 = fib_entry_get_resolving_interface (dst_fei);
+ if (sw_if_index0 != conn_sw_if_index0 ||
+ sw_if_index0 != fib_entry_get_resolving_interface (src_fei))
{
+ /*
+ * The interface the ARP is sent to or was received on is not the
+ * interface on which the covering prefix is configured.
+ * Maybe this is a case for unnumbered.
+ */
if (!arp_unnumbered (p0, sw_if_index0, conn_sw_if_index0))
{
error0 = ETHERNET_ARP_ERROR_unnumbered_mismatch;