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authorJuraj Sloboda <jsloboda@cisco.com>2017-02-08 23:54:21 -0800
committerOle Trøan <otroan@employees.org>2017-02-16 10:48:53 +0000
commitb33f413af46ec8dff7f222dbd5bc3bcec1502d3d (patch)
tree6c3118bfce76a0fe65f757b32d3d1d2f4b8d5789 /src/plugins/snat/out2in.c
parent205e934ee7530dac475be14d9054183625171ccc (diff)
Add handling of ICMP error packets in SNAT (VPP-629)
Change-Id: I8d2022b7cb3ef3da736c085bccbb5b9c057a8d76 Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
Diffstat (limited to 'src/plugins/snat/out2in.c')
-rw-r--r--src/plugins/snat/out2in.c199
1 files changed, 176 insertions, 23 deletions
diff --git a/src/plugins/snat/out2in.c b/src/plugins/snat/out2in.c
index 4f3322a3231..3c1bb8852f6 100644
--- a/src/plugins/snat/out2in.c
+++ b/src/plugins/snat/out2in.c
@@ -103,6 +103,7 @@ static char * snat_out2in_error_strings[] = {
typedef enum {
SNAT_OUT2IN_NEXT_DROP,
SNAT_OUT2IN_NEXT_LOOKUP,
+ SNAT_OUT2IN_NEXT_ICMP_ERROR,
SNAT_OUT2IN_N_NEXT,
} snat_out2in_next_t;
@@ -222,6 +223,10 @@ create_session_for_static_mapping (snat_main_t *sm,
return s;
}
+typedef struct {
+ u16 src_port, dst_port;
+} tcp_udp_header_t;
+
static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
vlib_buffer_t * b0,
ip4_header_t * ip0,
@@ -230,24 +235,73 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
u32 rx_fib_index0,
vlib_node_runtime_t * node,
u32 next0, f64 now,
- u32 cpu_index)
+ u32 cpu_index,
+ snat_session_t ** p_s0)
{
snat_session_key_t key0, sm0;
- icmp_echo_header_t *echo0;
+ icmp_echo_header_t *echo0, *inner_echo0 = 0;
+ ip4_header_t *inner_ip0 = 0;
+ void *l4_header = 0;
+ icmp46_header_t *inner_icmp0;
clib_bihash_kv_8_8_t kv0, value0;
- snat_session_t * s0;
+ snat_session_t * s0 = 0;
u32 new_addr0, old_addr0;
u16 old_id0, new_id0;
ip_csum_t sum0;
+ u16 checksum0;
snat_runtime_t * rt = (snat_runtime_t *)node->runtime_data;
+ u8 is_error_message = 0;
echo0 = (icmp_echo_header_t *)(icmp0+1);
key0.addr = ip0->dst_address;
- key0.port = echo0->identifier;
- key0.protocol = SNAT_PROTOCOL_ICMP;
key0.fib_index = rx_fib_index0;
-
+
+ switch(icmp0->type)
+ {
+ case ICMP4_destination_unreachable:
+ case ICMP4_time_exceeded:
+ case ICMP4_parameter_problem:
+ case ICMP4_source_quench:
+ case ICMP4_redirect:
+ case ICMP4_alternate_host_address:
+ is_error_message = 1;
+ }
+
+ if (!is_error_message)
+ {
+ if (PREDICT_FALSE(icmp0->type != ICMP4_echo_reply))
+ {
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
+ key0.protocol = SNAT_PROTOCOL_ICMP;
+ key0.port = echo0->identifier;
+ }
+ else
+ {
+ inner_ip0 = (ip4_header_t *)(echo0+1);
+ l4_header = ip4_next_header (inner_ip0);
+ key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
+ switch (key0.protocol)
+ {
+ case SNAT_PROTOCOL_ICMP:
+ inner_icmp0 = (icmp46_header_t*)l4_header;
+ inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
+ key0.port = inner_echo0->identifier;
+ break;
+ case SNAT_PROTOCOL_UDP:
+ case SNAT_PROTOCOL_TCP:
+ key0.port = ((tcp_udp_header_t*)l4_header)->src_port;
+ break;
+ default:
+ b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
+ }
+
kv0.key = key0.as_u64;
if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
@@ -271,43 +325,108 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
}
/* Don't NAT packet aimed at the intfc address */
- if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
- rt->cached_ip4_address))
- return next0;
+ if (PREDICT_FALSE(ip0->dst_address.as_u32 == rt->cached_ip4_address))
+ goto out;
b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
- return SNAT_OUT2IN_NEXT_DROP;
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
+
+ if (is_error_message)
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
}
/* Create session initiated by host from external network */
s0 = create_session_for_static_mapping(sm, b0, sm0, key0,
node, cpu_index);
+
if (!s0)
- return SNAT_OUT2IN_NEXT_DROP;
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
}
else
s0 = pool_elt_at_index (sm->per_thread_data[cpu_index].sessions,
value0.value);
+ sum0 = ip_incremental_checksum (0, icmp0,
+ ntohs(ip0->length) - ip4_header_bytes (ip0));
+ checksum0 = ~ip_csum_fold (sum0);
+ if (checksum0 != 0 && checksum0 != 0xffff)
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
+
old_addr0 = ip0->dst_address.as_u32;
ip0->dst_address = s0->in2out.addr;
new_addr0 = ip0->dst_address.as_u32;
vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
sum0 = ip0->checksum;
- sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
- ip4_header_t,
+ sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
dst_address /* changed member */);
ip0->checksum = ip_csum_fold (sum0);
- old_id0 = echo0->identifier;
- new_id0 = s0->in2out.port;
- echo0->identifier = new_id0;
+ if (!is_error_message)
+ {
+ old_id0 = echo0->identifier;
+ new_id0 = s0->in2out.port;
+ echo0->identifier = new_id0;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+ identifier /* changed member */);
+ icmp0->checksum = ip_csum_fold (sum0);
+ }
+ else
+ {
+ if (!ip4_header_checksum_is_valid (inner_ip0))
+ {
+ next0 = SNAT_OUT2IN_NEXT_DROP;
+ goto out;
+ }
+
+ old_addr0 = inner_ip0->src_address.as_u32;
+ inner_ip0->src_address = s0->in2out.addr;
+ new_addr0 = inner_ip0->src_address.as_u32;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+ src_address /* changed member */);
+ icmp0->checksum = ip_csum_fold (sum0);
- sum0 = icmp0->checksum;
- sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
- identifier);
- icmp0->checksum = ip_csum_fold (sum0);
+ switch (key0.protocol)
+ {
+ case SNAT_PROTOCOL_ICMP:
+ old_id0 = inner_echo0->identifier;
+ new_id0 = s0->in2out.port;
+ inner_echo0->identifier = new_id0;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+ identifier);
+ icmp0->checksum = ip_csum_fold (sum0);
+ break;
+ case SNAT_PROTOCOL_UDP:
+ case SNAT_PROTOCOL_TCP:
+ old_id0 = ((tcp_udp_header_t*)l4_header)->src_port;
+ new_id0 = s0->in2out.port;
+ ((tcp_udp_header_t*)l4_header)->src_port = new_id0;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
+ src_port);
+ icmp0->checksum = ip_csum_fold (sum0);
+ break;
+ default:
+ ASSERT(0);
+ }
+ }
/* Accounting */
s0->last_heard = now;
@@ -323,6 +442,8 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
s0->per_user_index);
}
+out:
+ *p_s0 = s0;
return next0;
}
@@ -410,11 +531,21 @@ snat_out2in_node_fn (vlib_main_t * vm,
if (PREDICT_FALSE (proto0 == ~0))
goto trace0;
+ if (PREDICT_FALSE(ip0->ttl == 1))
+ {
+ vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+ icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+ ICMP4_time_exceeded_ttl_exceeded_in_transit,
+ 0);
+ next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+ goto trace0;
+ }
+
if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
{
next0 = icmp_out2in_slow_path
(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
- next0, now, cpu_index);
+ next0, now, cpu_index, &s0);
goto trace0;
}
@@ -535,11 +666,21 @@ snat_out2in_node_fn (vlib_main_t * vm,
if (PREDICT_FALSE (proto1 == ~0))
goto trace1;
+ if (PREDICT_FALSE(ip0->ttl == 1))
+ {
+ vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+ icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
+ ICMP4_time_exceeded_ttl_exceeded_in_transit,
+ 0);
+ next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+ goto trace1;
+ }
+
if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
{
next1 = icmp_out2in_slow_path
(sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
- next1, now, cpu_index);
+ next1, now, cpu_index, &s1);
goto trace1;
}
@@ -694,11 +835,21 @@ snat_out2in_node_fn (vlib_main_t * vm,
if (PREDICT_FALSE (proto0 == ~0))
goto trace00;
+ if (PREDICT_FALSE(ip0->ttl == 1))
+ {
+ vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+ icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+ ICMP4_time_exceeded_ttl_exceeded_in_transit,
+ 0);
+ next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+ goto trace00;
+ }
+
if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
{
next0 = icmp_out2in_slow_path
(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
- next0, now, cpu_index);
+ next0, now, cpu_index, &s0);
goto trace00;
}
@@ -838,6 +989,7 @@ VLIB_REGISTER_NODE (snat_out2in_node) = {
.next_nodes = {
[SNAT_OUT2IN_NEXT_DROP] = "error-drop",
[SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+ [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);
@@ -1295,6 +1447,7 @@ VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
.next_nodes = {
[SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
[SNAT_OUT2IN_NEXT_DROP] = "error-drop",
+ [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
},
};
VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_fast_node, snat_out2in_fast_node_fn);