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Fix potential L2 forwarding crash with stale L2FIB entry (VPP-516)

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On moving interface between L2 and L3 forwarding modes, adjust the
l2-output node next index for the sw_if_index of the interface so
packet output via stale MAC entries in L2 FIB will be dropped.

Change-Id: I25afd7a617edb4ae35ce296bac33e62683edad9a
Signed-off-by: John Lo <loj@cisco.com>
This commit is contained in:
John Lo
2016-10-27 11:17:02 -04:00
committed by Dave Barach
parent 218170be70
commit 0fc9bc1206
4 changed files with 44 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
vnet/vnet/l2/l2_input.c
View File

@ -606,22 +606,29 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main, u32 mode, u32 sw_if_
l2_if_adjust--;
}
/*
* Directs the l2 output path to work out the interface
* output next-arc itself. Needed when recycling a sw_if_index.
*/
vec_validate_init_empty (l2om->next_nodes.output_node_index_vec,
sw_if_index, ~0);
l2om->next_nodes.output_node_index_vec[sw_if_index] = ~0;
/* Initialize the l2-input configuration for the interface */
if (mode == MODE_L3)
{
/* Set L2 config to BD index 0 so that if any packet accidentally
* came in on L2 path, it will be dropped in BD 0 */
config->xconnect = 0;
config->bridge = 0;
config->shg = 0;
config->bd_index = 0;
config->feature_bitmap = L2INPUT_FEAT_DROP;
/*
* Directs the l2 output path to work out the interface
* output next-arc itself. Needed when recycling a sw_if_index.
*/
vec_validate_init_empty (l2om->next_nodes.output_node_index_vec,
sw_if_index, ~0);
l2om->next_nodes.output_node_index_vec[sw_if_index] = ~0;
/* Make sure any L2-output packet to this interface now in L3 mode is
* dropped. This may happen if L2 FIB MAC entry is stale */
l2om->next_nodes.output_node_index_vec[sw_if_index] =
L2OUTPUT_NEXT_BAD_INTF;
}
else if (mode == MODE_L2_CLASSIFY)
{

58
vnet/vnet/l2/l2_output.c
View File

@ -469,46 +469,46 @@ VLIB_REGISTER_NODE (l2output_node,static) = {
/* edit / add dispositions here */
.next_nodes = {
[L2OUTPUT_NEXT_DROP] = "error-drop",
[L2OUTPUT_NEXT_DEL_TUNNEL] = "l2-output-del-tunnel",
[L2OUTPUT_NEXT_BAD_INTF] = "l2-output-bad-intf",
},
};
/* *INDENT-ON* */
#define foreach_l2output_del_tunnel_error \
_(DROP, "L2 output to deleted tunnel")
#define foreach_l2output_bad_intf_error \
_(DROP, "L2 output to interface not in L2 mode or deleted")
static char *l2output_del_tunnel_error_strings[] = {
static char *l2output_bad_intf_error_strings[] = {
#define _(sym,string) string,
foreach_l2output_del_tunnel_error
foreach_l2output_bad_intf_error
#undef _
};
typedef enum
{
#define _(sym,str) L2OUTPUT_DEL_TUNNEL_ERROR_##sym,
foreach_l2output_del_tunnel_error
#define _(sym,str) L2OUTPUT_BAD_INTF_ERROR_##sym,
foreach_l2output_bad_intf_error
#undef _
L2OUTPUT_DEL_TUNNEL_N_ERROR,
} l2output_del_tunnel_error_t;
L2OUTPUT_BAD_INTF_N_ERROR,
} l2output_bad_intf_error_t;
/**
* Output node for tunnels which was in L2 BD's but were deleted.
* On deletion of any tunnel which was on a L2 BD, its entry in
* l2_output_main table next_nodes.output_node_index_vec[sw_if_index]
* MUST be set to the value of L2OUTPUT_NEXT_DEL_TUNNEL. Thus, if there
* are stale entries in the L2FIB for this tunnel sw_if_index, l2-output
* will send packets for this sw_if_index to the l2-output-tunnel-del
* node which just setup the proper drop reason before sending packets
* to the error-drop node to drop the packet. Then, stale L2FIB entries
* for delted tunnels won't cause possible packet or memory corrpution.
* Output node for interfaces/tunnels which was in L2 mode but were changed
* to L3 mode or possibly deleted thereafter. On changing forwarding mode
* of any tunnel/interface from L2 to L3, its entry in l2_output_main table
* next_nodes.output_node_index_vec[sw_if_index] MUST be set to the value of
* L2OUTPUT_NEXT_BAD_INTF. Thus, if there are stale entries in the L2FIB for
* this sw_if_index, l2-output will send packets for this sw_if_index to the
* l2-output-bad-intf node which just setup the proper drop reason before
* sending packets to the error-drop node to drop the packet. Then, stale L2FIB
* entries for delted tunnels won't cause possible packet or memory corrpution.
*/
static vlib_node_registration_t l2output_del_tunnel_node;
static vlib_node_registration_t l2output_bad_intf_node;
static uword
l2output_del_tunnel_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * frame)
l2output_bad_intf_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * frame)
{
u32 n_left_from, *from, *to_next;
l2output_next_t next_index = 0;
@ -536,8 +536,8 @@ l2output_del_tunnel_node_fn (vlib_main_t * vm,
n_left_to_next -= 2;
b0 = vlib_get_buffer (vm, bi0);
b1 = vlib_get_buffer (vm, bi1);
b0->error = node->errors[L2OUTPUT_DEL_TUNNEL_ERROR_DROP];
b1->error = node->errors[L2OUTPUT_DEL_TUNNEL_ERROR_DROP];
b0->error = node->errors[L2OUTPUT_BAD_INTF_ERROR_DROP];
b1->error = node->errors[L2OUTPUT_BAD_INTF_ERROR_DROP];
}
while (n_left_from > 0 && n_left_to_next > 0)
@ -552,7 +552,7 @@ l2output_del_tunnel_node_fn (vlib_main_t * vm,
n_left_from -= 1;
n_left_to_next -= 1;
b0 = vlib_get_buffer (vm, bi0);
b0->error = node->errors[L2OUTPUT_DEL_TUNNEL_ERROR_DROP];
b0->error = node->errors[L2OUTPUT_BAD_INTF_ERROR_DROP];
}
vlib_put_next_frame (vm, node, next_index, n_left_to_next);
@ -562,14 +562,14 @@ l2output_del_tunnel_node_fn (vlib_main_t * vm,
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (l2output_del_tunnel_node,static) = {
.function = l2output_del_tunnel_node_fn,
.name = "l2-output-del-tunnel",
VLIB_REGISTER_NODE (l2output_bad_intf_node,static) = {
.function = l2output_bad_intf_node_fn,
.name = "l2-output-bad-intf",
.vector_size = sizeof (u32),
.type = VLIB_NODE_TYPE_INTERNAL,
.n_errors = ARRAY_LEN(l2output_del_tunnel_error_strings),
.error_strings = l2output_del_tunnel_error_strings,
.n_errors = ARRAY_LEN(l2output_bad_intf_error_strings),
.error_strings = l2output_bad_intf_error_strings,
.n_next_nodes = 1,

2
vnet/vnet/l2/l2_output.h
View File

@ -134,7 +134,7 @@ _(MAPPING_DROP, "L2 Output interface mapping in progress")
typedef enum
{
L2OUTPUT_NEXT_DROP,
L2OUTPUT_NEXT_DEL_TUNNEL,
L2OUTPUT_NEXT_BAD_INTF,
L2OUTPUT_N_NEXT,
} l2output_next_t;

13
vnet/vnet/vxlan/vxlan.c
View File

@ -214,7 +214,6 @@ int vnet_vxlan_add_del_tunnel
int rv;
vxlan4_tunnel_key_t key4;
vxlan6_tunnel_key_t key6;
l2output_main_t * l2om = &l2output_main;
if (!a->is_ip6) {
key4.src = a->dst.ip4.as_u32; /* decap src in key is encap dst in config */
@ -327,14 +326,6 @@ int vnet_vxlan_add_del_tunnel
l2im->configs[sw_if_index].bd_index = 0;
}
/*
* Directs the l2 output path to work out the interface
* output next-arc itself. Needed when recycling a tunnel.
*/
vec_validate_init_empty(l2om->next_nodes.output_node_index_vec,
sw_if_index, ~0);
l2om->next_nodes.output_node_index_vec[t->sw_if_index]
= ~0;
vnet_sw_interface_set_flags (vnm, sw_if_index,
VNET_SW_INTERFACE_FLAG_ADMIN_UP);
if (!a->is_ip6) {
@ -362,10 +353,6 @@ int vnet_vxlan_add_del_tunnel
vxm->tunnel_index_by_sw_if_index[t->sw_if_index] = ~0;
/* Directs the l2 path to turf packets sent to this sw_if_index */
l2om->next_nodes.output_node_index_vec[t->sw_if_index]
= L2OUTPUT_NEXT_DEL_TUNNEL;
if (!a->is_ip6)
{
hash_unset (vxm->vxlan4_tunnel_by_key, key4.as_u64);