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/*
* esp_decrypt.c : IPSec ESP decrypt node
*
* Copyright (c) 2015 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <vnet/vnet.h>
#include <vnet/api_errno.h>
#include <vnet/ip/ip.h>
#include <vnet/ipsec/ipsec.h>
#include <vnet/ipsec/esp.h>
#define foreach_esp_decrypt_next \
_(DROP, "error-drop") \
_(IP4_INPUT, "ip4-input") \
_(IP6_INPUT, "ip6-input") \
_(IPSEC_GRE_INPUT, "ipsec-gre-input")
#define _(v, s) ESP_DECRYPT_NEXT_##v,
typedef enum
{
foreach_esp_decrypt_next
#undef _
ESP_DECRYPT_N_NEXT,
} esp_decrypt_next_t;
#define foreach_esp_decrypt_error \
_(RX_PKTS, "ESP pkts received") \
_(NO_BUFFER, "No buffer (packed dropped)") \
_(DECRYPTION_FAILED, "ESP decryption failed") \
_(INTEG_ERROR, "Integrity check failed") \
_(REPLAY, "SA replayed packet") \
_(NOT_IP, "Not IP packet (dropped)")
typedef enum
{
#define _(sym,str) ESP_DECRYPT_ERROR_##sym,
foreach_esp_decrypt_error
#undef _
ESP_DECRYPT_N_ERROR,
} esp_decrypt_error_t;
static char *esp_decrypt_error_strings[] = {
#define _(sym,string) string,
foreach_esp_decrypt_error
#undef _
};
typedef struct
{
ipsec_crypto_alg_t crypto_alg;
ipsec_integ_alg_t integ_alg;
} esp_decrypt_trace_t;
/* packet trace format function */
static u8 *
format_esp_decrypt_trace (u8 * s, va_list * args)
{
CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
s = format (s, "esp: crypto %U integrity %U",
format_ipsec_crypto_alg, t->crypto_alg,
format_ipsec_integ_alg, t->integ_alg);
return s;
}
always_inline void
esp_decrypt_cbc (ipsec_crypto_alg_t alg,
u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
{
ipsec_proto_main_t *em = &ipsec_proto_main;
u32 thread_index = vlib_get_thread_index ();
#if OPENSSL_VERSION_NUMBER >= 0x10100000L
EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].decrypt_ctx;
#else
EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].decrypt_ctx);
#endif
const EVP_CIPHER *cipher = NULL;
int out_len;
ASSERT (alg < IPSEC_CRYPTO_N_ALG);
if (PREDICT_FALSE (em->ipsec_proto_main_crypto_algs[alg].type == 0))
return;
if (PREDICT_FALSE
(alg != em->per_thread_data[thread_index].last_decrypt_alg))
{
cipher = em->ipsec_proto_main_crypto_algs[alg].type;
em->per_thread_data[thread_index].last_decrypt_alg = alg;
}
EVP_DecryptInit_ex (ctx, cipher, NULL, key, iv);
EVP_DecryptUpdate (ctx, out, &out_len, in, in_len);
EVP_DecryptFinal_ex (ctx, out + out_len, &out_len);
}
always_inline uword
esp_decrypt_inline (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame,
int is_ip6)
{
u32 n_left_from, *from, next_index, *to_next;
ipsec_main_t *im = &ipsec_main;
ipsec_proto_main_t *em = &ipsec_proto_main;
u32 *recycle = 0;
from = vlib_frame_vector_args (from_frame);
n_left_from = from_frame->n_vectors;
u32 thread_index = vlib_get_thread_index ();
ipsec_alloc_empty_buffers (vm, im);
u32 *empty_buffers = im->empty_buffers[thread_index];
if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
{
if (is_ip6)
vlib_node_increment_counter (vm, esp6_decrypt_node.index,
ESP_DECRYPT_ERROR_NO_BUFFER,
n_left_from);
else
vlib_node_increment_counter (vm, esp4_decrypt_node.index,
ESP_DECRYPT_ERROR_NO_BUFFER,
n_left_from);
goto free_buffers_and_exit;
}
next_index = node->cached_next_index;
while (n_left_from > 0)
{
u32 n_left_to_next;
vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
while (n_left_from > 0 && n_left_to_next > 0)
{
u32 i_bi0, o_bi0 = (u32) ~ 0, next0;
vlib_buffer_t *i_b0;
vlib_buffer_t *o_b0 = 0;
esp_header_t *esp0;
ipsec_sa_t *sa0;
u32 sa_index0 = ~0;
u32 seq;
ip4_header_t *ih4 = 0, *oh4 = 0;
ip6_header_t *ih6 = 0, *oh6 = 0;
u8 tunnel_mode = 1;
i_bi0 = from[0];
from += 1;
n_left_from -= 1;
n_left_to_next -= 1;
next0 = ESP_DECRYPT_NEXT_DROP;
i_b0 = vlib_get_buffer (vm, i_bi0);
esp0 = vlib_buffer_get_current (i_b0);
sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
sa0 = pool_elt_at_index (im->sad, sa_index0);
seq = clib_host_to_net_u32 (esp0->seq);
/* anti-replay check */
if (sa0->use_anti_replay)
{
int rv = 0;
if (PREDICT_TRUE (sa0->use_esn))
rv = esp_replay_check_esn (sa0, seq);
else
rv = esp_replay_check (sa0, seq);
if (PREDICT_FALSE (rv))
{
clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
if (is_ip6)
vlib_node_increment_counter (vm,
esp6_decrypt_node.index,
ESP_DECRYPT_ERROR_REPLAY, 1);
else
vlib_node_increment_counter (vm,
esp4_decrypt_node.index,
ESP_DECRYPT_ERROR_REPLAY, 1);
o_bi0 = i_bi0;
to_next[0] = o_bi0;
to_next += 1;
goto trace;
}
}
sa0->total_data_size += i_b0->current_length;
if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
{
u8 sig[64];
int icv_size =
em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
memset (sig, 0, sizeof (sig));
u8 *icv =
vlib_buffer_get_current (i_b0) + i_b0->current_length -
icv_size;
i_b0->current_length -= icv_size;
hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
(u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
sa0->seq_hi);
if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
{
if (is_ip6)
vlib_node_increment_counter (vm,
esp6_decrypt_node.index,
ESP_DECRYPT_ERROR_INTEG_ERROR,
1);
else
vlib_node_increment_counter (vm,
esp4_decrypt_node.index,
ESP_DECRYPT_ERROR_INTEG_ERROR,
1);
o_bi0 = i_bi0;
to_next[0] = o_bi0;
to_next += 1;
goto trace;
}
}
if (PREDICT_TRUE (sa0->use_anti_replay))
{
if (PREDICT_TRUE (sa0->use_esn))
esp_replay_advance_esn (sa0, seq);
else
esp_replay_advance (sa0, seq);
}
/* grab free buffer */
uword last_empty_buffer = vec_len (empty_buffers) - 1;
o_bi0 = empty_buffers[last_empty_buffer];
to_next[0] = o_bi0;
to_next += 1;
o_b0 = vlib_get_buffer (vm, o_bi0);
vlib_prefetch_buffer_with_index (vm,
empty_buffers[last_empty_buffer -
1], STORE);
_vec_len (empty_buffers) = last_empty_buffer;
/* add old buffer to the recycle list */
vec_add1 (recycle, i_bi0);
if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
(sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
{
const int BLOCK_SIZE =
em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
const int IV_SIZE =
em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
esp_footer_t *f0;
u8 ip_hdr_size = 0;
int blocks =
(i_b0->current_length - sizeof (esp_header_t) -
IV_SIZE) / BLOCK_SIZE;
o_b0->current_data = sizeof (ethernet_header_t);
/* transport mode */
if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
{
tunnel_mode = 0;
if (is_ip6)
{
ih6 =
(ip6_header_t *) ((u8 *) esp0 -
sizeof (ip6_header_t));
ip_hdr_size = sizeof (ip6_header_t);
oh6 = vlib_buffer_get_current (o_b0);
}
else
{
ih4 =
(ip4_header_t *) ((u8 *) esp0 -
sizeof (ip4_header_t));
oh4 = vlib_buffer_get_current (o_b0);
ip_hdr_size = sizeof (ip4_header_t);
}
}
esp_decrypt_cbc (sa0->crypto_alg,
esp0->data + IV_SIZE,
(u8 *) vlib_buffer_get_current (o_b0) +
ip_hdr_size, BLOCK_SIZE * blocks,
sa0->crypto_key, esp0->data);
o_b0->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
f0 =
(esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
o_b0->current_length);
o_b0->current_length -= f0->pad_length;
/* tunnel mode */
if (PREDICT_TRUE (tunnel_mode))
{
if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
{
next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
oh4 = vlib_buffer_get_current (o_b0);
}
else if (f0->next_header == IP_PROTOCOL_IPV6)
next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
else
{
clib_warning ("next header: 0x%x", f0->next_header);
if (is_ip6)
vlib_node_increment_counter (vm,
esp6_decrypt_node.index,
ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
1);
else
vlib_node_increment_counter (vm,
esp4_decrypt_node.index,
ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
1);
o_b0 = 0;
goto trace;
}
}
/* transport mode */
else
{
if (is_ip6)
{
next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
oh6->ip_version_traffic_class_and_flow_label =
ih6->ip_version_traffic_class_and_flow_label;
oh6->protocol = f0->next_header;
oh6->hop_limit = ih6->hop_limit;
oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
oh6->payload_length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain
(vm,
o_b0) - sizeof (ip6_header_t));
}
else
{
next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
oh4->ip_version_and_header_length = 0x45;
oh4->tos = ih4->tos;
oh4->fragment_id = 0;
oh4->flags_and_fragment_offset = 0;
oh4->ttl = ih4->ttl;
oh4->protocol = f0->next_header;
oh4->src_address.as_u32 = ih4->src_address.as_u32;
oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
oh4->length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain
(vm, o_b0));
oh4->checksum = ip4_header_checksum (oh4);
}
}
/* for IPSec-GRE tunnel next node is ipsec-gre-input */
if (PREDICT_FALSE
((vnet_buffer (i_b0)->ipsec.flags) &
IPSEC_FLAG_IPSEC_GRE_TUNNEL))
next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
}
trace:
if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
{
if (o_b0)
{
o_b0->flags |= VLIB_BUFFER_IS_TRACED;
o_b0->trace_index = i_b0->trace_index;
esp_decrypt_trace_t *tr =
vlib_add_trace (vm, node, o_b0, sizeof (*tr));
tr->crypto_alg = sa0->crypto_alg;
tr->integ_alg = sa0->integ_alg;
}
}
vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
n_left_to_next, o_bi0, next0);
}
vlib_put_next_frame (vm, node, next_index, n_left_to_next);
}
if (is_ip6)
vlib_node_increment_counter (vm, esp6_decrypt_node.index,
ESP_DECRYPT_ERROR_RX_PKTS,
from_frame->n_vectors);
else
vlib_node_increment_counter (vm, esp4_decrypt_node.index,
ESP_DECRYPT_ERROR_RX_PKTS,
from_frame->n_vectors);
free_buffers_and_exit:
if (recycle)
vlib_buffer_free (vm, recycle, vec_len (recycle));
vec_free (recycle);
return from_frame->n_vectors;
}
static uword
esp4_decrypt_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (esp4_decrypt_node) = {
.function = esp4_decrypt_node_fn,
.name = "esp4-decrypt",
.vector_size = sizeof (u32),
.format_trace = format_esp_decrypt_trace,
.type = VLIB_NODE_TYPE_INTERNAL,
.n_errors = ARRAY_LEN(esp_decrypt_error_strings),
.error_strings = esp_decrypt_error_strings,
.n_next_nodes = ESP_DECRYPT_N_NEXT,
.next_nodes = {
#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
foreach_esp_decrypt_next
#undef _
},
};
/* *INDENT-ON* */
VLIB_NODE_FUNCTION_MULTIARCH (esp4_decrypt_node, esp4_decrypt_node_fn);
static uword
esp6_decrypt_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (esp6_decrypt_node) = {
.function = esp6_decrypt_node_fn,
.name = "esp6-decrypt",
.vector_size = sizeof (u32),
.format_trace = format_esp_decrypt_trace,
.type = VLIB_NODE_TYPE_INTERNAL,
.n_errors = ARRAY_LEN(esp_decrypt_error_strings),
.error_strings = esp_decrypt_error_strings,
.n_next_nodes = ESP_DECRYPT_N_NEXT,
.next_nodes = {
#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
foreach_esp_decrypt_next
#undef _
},
};
/* *INDENT-ON* */
VLIB_NODE_FUNCTION_MULTIARCH (esp6_decrypt_node, esp6_decrypt_node_fn);
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/