blob: c487d82e34a3ff2c3adfae489e4ebb568667a565 [file] [log] [blame]
/*
* ah_decrypt.c : IPSec AH 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>
#include <vnet/ipsec/ah.h>
#define foreach_ah_decrypt_next \
_(DROP, "error-drop") \
_(IP4_INPUT, "ip4-input") \
_(IP6_INPUT, "ip6-input") \
_(IPSEC_GRE_INPUT, "ipsec-gre-input")
#define _(v, s) AH_DECRYPT_NEXT_##v,
typedef enum
{
foreach_ah_decrypt_next
#undef _
AH_DECRYPT_N_NEXT,
} ah_decrypt_next_t;
#define foreach_ah_decrypt_error \
_(RX_PKTS, "AH pkts received") \
_(DECRYPTION_FAILED, "AH decryption failed") \
_(INTEG_ERROR, "Integrity check failed") \
_(REPLAY, "SA replayed packet") \
_(NOT_IP, "Not IP packet (dropped)")
typedef enum
{
#define _(sym,str) AH_DECRYPT_ERROR_##sym,
foreach_ah_decrypt_error
#undef _
AH_DECRYPT_N_ERROR,
} ah_decrypt_error_t;
static char *ah_decrypt_error_strings[] = {
#define _(sym,string) string,
foreach_ah_decrypt_error
#undef _
};
typedef struct
{
ipsec_integ_alg_t integ_alg;
} ah_decrypt_trace_t;
/* packet trace format function */
static u8 *
format_ah_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 *);
ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *);
s = format (s, "ah: integrity %U", format_ipsec_integ_alg, t->integ_alg);
return s;
}
static uword
ah_decrypt_node_fn (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame)
{
u32 n_left_from, *from, next_index, *to_next;
ipsec_main_t *im = &ipsec_main;
ipsec_proto_main_t *em = &ipsec_proto_main;
from = vlib_frame_vector_args (from_frame);
n_left_from = from_frame->n_vectors;
int icv_size = 0;
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;
u32 next0;
vlib_buffer_t *i_b0;
ah_header_t *ah0;
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;
u8 transport_ip6 = 0;
u8 ip_hdr_size = 0;
u8 tos = 0;
u8 ttl = 0;
i_bi0 = from[0];
from += 1;
n_left_from -= 1;
n_left_to_next -= 1;
next0 = AH_DECRYPT_NEXT_DROP;
i_b0 = vlib_get_buffer (vm, i_bi0);
to_next[0] = i_bi0;
to_next += 1;
ih4 = vlib_buffer_get_current (i_b0);
ip_hdr_size = ip4_header_bytes (ih4);
ah0 = (ah_header_t *) ((u8 *) ih4 + ip_hdr_size);
sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
sa0 = pool_elt_at_index (im->sad, sa_index0);
seq = clib_host_to_net_u32 (ah0->seq_no);
/* anti-replay check */
//TODO UT remaining
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);
vlib_node_increment_counter (vm, ah_decrypt_node.index,
AH_DECRYPT_ERROR_REPLAY, 1);
to_next[0] = i_bi0;
to_next += 1;
goto trace;
}
}
sa0->total_data_size += i_b0->current_length;
icv_size =
em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
{
u8 sig[64];
u8 digest[64];
memset (sig, 0, sizeof (sig));
memset (digest, 0, sizeof (digest));
u8 *icv =
vlib_buffer_get_current (i_b0) + ip_hdr_size +
sizeof (ah_header_t);
memcpy (digest, icv, icv_size);
memset (icv, 0, icv_size);
if ((ih4->ip_version_and_header_length & 0xF0) == 0x40)
{
tos = ih4->tos;
ttl = ih4->ttl;
ih4->tos = 0;
ih4->ttl = 0;
ih4->checksum = 0;
ih4->flags_and_fragment_offset = 0;
} //TODO else part for IPv6
hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
(u8 *) ih4, i_b0->current_length, sig, sa0->use_esn,
sa0->seq_hi);
if (PREDICT_FALSE (memcmp (digest, sig, icv_size)))
{
vlib_node_increment_counter (vm, ah_decrypt_node.index,
AH_DECRYPT_ERROR_INTEG_ERROR,
1);
to_next[0] = i_bi0;
to_next += 1;
goto trace;
}
//TODO UT remaining
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);
}
}
vlib_buffer_advance (i_b0,
ip_hdr_size + sizeof (ah_header_t) + icv_size);
i_b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
/* transport mode */
if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
{
tunnel_mode = 0;
if (PREDICT_TRUE
((ih4->ip_version_and_header_length & 0xF0) != 0x40))
{
if (PREDICT_TRUE
((ih4->ip_version_and_header_length & 0xF0) == 0x60))
transport_ip6 = 1;
else
{
clib_warning ("next header: 0x%x", ah0->nexthdr);
vlib_node_increment_counter (vm, ah_decrypt_node.index,
AH_DECRYPT_ERROR_NOT_IP,
1);
goto trace;
}
}
}
if (PREDICT_TRUE (tunnel_mode))
{
if (PREDICT_TRUE (ah0->nexthdr == IP_PROTOCOL_IP_IN_IP))
next0 = AH_DECRYPT_NEXT_IP4_INPUT;
else if (ah0->nexthdr == IP_PROTOCOL_IPV6)
next0 = AH_DECRYPT_NEXT_IP6_INPUT;
else
{
clib_warning ("next header: 0x%x", ah0->nexthdr);
vlib_node_increment_counter (vm, ah_decrypt_node.index,
AH_DECRYPT_ERROR_DECRYPTION_FAILED,
1);
goto trace;
}
}
/* transport mode */
else
{
if (PREDICT_FALSE (transport_ip6))
{
ih6 =
(ip6_header_t *) (i_b0->data +
sizeof (ethernet_header_t));
vlib_buffer_advance (i_b0, -sizeof (ip6_header_t));
oh6 = vlib_buffer_get_current (i_b0);
memmove (oh6, ih6, sizeof (ip6_header_t));
next0 = AH_DECRYPT_NEXT_IP6_INPUT;
oh6->protocol = ah0->nexthdr;
oh6->payload_length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain
(vm, i_b0) - sizeof (ip6_header_t));
}
else
{
vlib_buffer_advance (i_b0, -sizeof (ip4_header_t));
oh4 = vlib_buffer_get_current (i_b0);
memmove (oh4, ih4, sizeof (ip4_header_t));
next0 = AH_DECRYPT_NEXT_IP4_INPUT;
oh4->ip_version_and_header_length = 0x45;
oh4->fragment_id = 0;
oh4->flags_and_fragment_offset = 0;
oh4->protocol = ah0->nexthdr;
oh4->length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain
(vm, i_b0));
oh4->ttl = ttl;
oh4->tos = tos;
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 = AH_DECRYPT_NEXT_IPSEC_GRE_INPUT;
vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
trace:
if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
{
i_b0->flags |= VLIB_BUFFER_IS_TRACED;
ah_decrypt_trace_t *tr =
vlib_add_trace (vm, node, i_b0, sizeof (*tr));
tr->integ_alg = sa0->integ_alg;
}
vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
n_left_to_next, i_bi0, next0);
}
vlib_put_next_frame (vm, node, next_index, n_left_to_next);
}
vlib_node_increment_counter (vm, ah_decrypt_node.index,
AH_DECRYPT_ERROR_RX_PKTS,
from_frame->n_vectors);
return from_frame->n_vectors;
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ah_decrypt_node) = {
.function = ah_decrypt_node_fn,
.name = "ah-decrypt",
.vector_size = sizeof (u32),
.format_trace = format_ah_decrypt_trace,
.type = VLIB_NODE_TYPE_INTERNAL,
.n_errors = ARRAY_LEN(ah_decrypt_error_strings),
.error_strings = ah_decrypt_error_strings,
.n_next_nodes = AH_DECRYPT_N_NEXT,
.next_nodes = {
#define _(s,n) [AH_DECRYPT_NEXT_##s] = n,
foreach_ah_decrypt_next
#undef _
},
};
/* *INDENT-ON* */
VLIB_NODE_FUNCTION_MULTIARCH (ah_decrypt_node, ah_decrypt_node_fn)
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/