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/*
* 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>
#include <vnet/ipsec/ipsec_io.h>
#define foreach_ah_decrypt_next \
_(DROP, "error-drop") \
_(IP4_INPUT, "ip4-input") \
_(IP6_INPUT, "ip6-input") \
_(HANDOFF, "handoff")
#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") \
_ (NO_TAIL_SPACE, "not enough buffer tail space (dropped)") \
_ (DROP_FRAGMENTS, "IP fragments drop") \
_ (REPLAY, "SA replayed packet")
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;
u32 seq_num;
} 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 seq-num %d",
format_ipsec_integ_alg, t->integ_alg, t->seq_num);
return s;
}
typedef struct
{
union
{
struct
{
u8 hop_limit;
u8 nexthdr;
u32 ip_version_traffic_class_and_flow_label;
};
struct
{
u8 ttl;
u8 tos;
};
};
u32 sa_index;
u32 seq;
u8 icv_padding_len;
u8 icv_size;
u8 ip_hdr_size;
i16 current_data;
u8 nexthdr_cached;
} ah_decrypt_packet_data_t;
static_always_inline void
ah_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node,
vnet_crypto_op_t * ops, vlib_buffer_t * b[], u16 * nexts)
{
u32 n_fail, n_ops = vec_len (ops);
vnet_crypto_op_t *op = ops;
if (n_ops == 0)
return;
n_fail = n_ops - vnet_crypto_process_ops (vm, op, n_ops);
while (n_fail)
{
ASSERT (op - ops < n_ops);
if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
{
u32 bi = op->user_data;
b[bi]->error = node->errors[AH_DECRYPT_ERROR_INTEG_ERROR];
nexts[bi] = AH_DECRYPT_NEXT_DROP;
n_fail--;
}
op++;
}
}
always_inline uword
ah_decrypt_inline (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame,
int is_ip6)
{
u32 n_left, *from;
u32 thread_index = vm->thread_index;
u16 buffer_data_size = vlib_buffer_get_default_data_size (vm);
ah_decrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
ipsec_main_t *im = &ipsec_main;
ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
from = vlib_frame_vector_args (from_frame);
n_left = from_frame->n_vectors;
ipsec_sa_t *sa0 = 0;
u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
clib_memset (pkt_data, 0, VLIB_FRAME_SIZE * sizeof (pkt_data[0]));
vlib_get_buffers (vm, from, b, n_left);
clib_memset_u16 (nexts, -1, n_left);
vec_reset_length (ptd->integ_ops);
while (n_left > 0)
{
ah_header_t *ah0;
ip4_header_t *ih4;
ip6_header_t *ih6;
if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
{
if (current_sa_index != ~0)
vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
current_sa_index,
current_sa_pkts,
current_sa_bytes);
current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
sa0 = pool_elt_at_index (im->sad, current_sa_index);
current_sa_bytes = current_sa_pkts = 0;
vlib_prefetch_combined_counter (&ipsec_sa_counters,
thread_index, current_sa_index);
}
if (PREDICT_FALSE (~0 == sa0->thread_index))
{
/* this is the first packet to use this SA, claim the SA
* for this thread. this could happen simultaneously on
* another thread */
clib_atomic_cmp_and_swap (&sa0->thread_index, ~0,
ipsec_sa_assign_thread (thread_index));
}
if (PREDICT_TRUE (thread_index != sa0->thread_index))
{
vnet_buffer (b[0])->ipsec.thread_index = sa0->thread_index;
next[0] = AH_DECRYPT_NEXT_HANDOFF;
goto next;
}
pd->sa_index = current_sa_index;
ih4 = vlib_buffer_get_current (b[0]);
ih6 = vlib_buffer_get_current (b[0]);
pd->current_data = b[0]->current_data;
if (is_ip6)
{
ip6_ext_header_t *prev = NULL;
ah0 =
ip6_ext_header_find (vm, b[0], ih6, IP_PROTOCOL_IPSEC_AH, &prev);
pd->ip_hdr_size = sizeof (ip6_header_t);
ASSERT ((u8 *) ah0 - (u8 *) ih6 == pd->ip_hdr_size);
}
else
{
if (ip4_is_fragment (ih4))
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_DROP_FRAGMENTS];
next[0] = AH_DECRYPT_NEXT_DROP;
goto next;
}
pd->ip_hdr_size = ip4_header_bytes (ih4);
ah0 = (ah_header_t *) ((u8 *) ih4 + pd->ip_hdr_size);
}
pd->seq = clib_host_to_net_u32 (ah0->seq_no);
/* anti-replay check */
if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_REPLAY];
next[0] = AH_DECRYPT_NEXT_DROP;
goto next;
}
current_sa_bytes += b[0]->current_length;
current_sa_pkts += 1;
pd->icv_size = sa0->integ_icv_size;
pd->nexthdr_cached = ah0->nexthdr;
if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
{
if (PREDICT_FALSE (ipsec_sa_is_set_USE_ESN (sa0) &&
pd->current_data + b[0]->current_length
+ sizeof (u32) > buffer_data_size))
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_NO_TAIL_SPACE];
next[0] = AH_DECRYPT_NEXT_DROP;
goto next;
}
vnet_crypto_op_t *op;
vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);
vnet_crypto_op_init (op, sa0->integ_op_id);
op->src = (u8 *) ih4;
op->len = b[0]->current_length;
op->digest = (u8 *) ih4 - pd->icv_size;
op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
op->digest_len = pd->icv_size;
op->key_index = sa0->integ_key_index;
op->user_data = b - bufs;
if (ipsec_sa_is_set_USE_ESN (sa0))
{
u32 seq_hi = clib_host_to_net_u32 (sa0->seq_hi);
op->len += sizeof (seq_hi);
clib_memcpy (op->src + b[0]->current_length, &seq_hi,
sizeof (seq_hi));
}
clib_memcpy (op->digest, ah0->auth_data, pd->icv_size);
clib_memset (ah0->auth_data, 0, pd->icv_size);
if (is_ip6)
{
pd->ip_version_traffic_class_and_flow_label =
ih6->ip_version_traffic_class_and_flow_label;
pd->hop_limit = ih6->hop_limit;
ih6->ip_version_traffic_class_and_flow_label = 0x60;
ih6->hop_limit = 0;
pd->nexthdr = ah0->nexthdr;
pd->icv_padding_len =
ah_calc_icv_padding_len (pd->icv_size, 1 /* is_ipv6 */ );
}
else
{
pd->tos = ih4->tos;
pd->ttl = ih4->ttl;
ih4->tos = 0;
ih4->ttl = 0;
ih4->checksum = 0;
pd->icv_padding_len =
ah_calc_icv_padding_len (pd->icv_size, 0 /* is_ipv6 */ );
}
}
next:
n_left -= 1;
pd += 1;
next += 1;
b += 1;
}
n_left = from_frame->n_vectors;
next = nexts;
pd = pkt_data;
b = bufs;
vlib_node_increment_counter (vm, node->node_index, AH_DECRYPT_ERROR_RX_PKTS,
n_left);
vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
current_sa_index, current_sa_pkts,
current_sa_bytes);
ah_process_ops (vm, node, ptd->integ_ops, bufs, nexts);
while (n_left > 0)
{
ip4_header_t *oh4;
ip6_header_t *oh6;
if (next[0] < AH_DECRYPT_N_NEXT)
goto trace;
sa0 = vec_elt_at_index (im->sad, pd->sa_index);
if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
{
/* redo the anit-reply check. see esp_decrypt for details */
if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_REPLAY];
next[0] = AH_DECRYPT_NEXT_DROP;
goto trace;
}
ipsec_sa_anti_replay_advance (sa0, pd->seq);
}
u16 ah_hdr_len = sizeof (ah_header_t) + pd->icv_size
+ pd->icv_padding_len;
vlib_buffer_advance (b[0], pd->ip_hdr_size + ah_hdr_len);
b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
{ /* tunnel mode */
if (PREDICT_TRUE (pd->nexthdr_cached == IP_PROTOCOL_IP_IN_IP))
next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
else if (pd->nexthdr_cached == IP_PROTOCOL_IPV6)
next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
else
{
b[0]->error = node->errors[AH_DECRYPT_ERROR_DECRYPTION_FAILED];
next[0] = AH_DECRYPT_NEXT_DROP;
goto trace;
}
}
else
{ /* transport mode */
if (is_ip6)
{
vlib_buffer_advance (b[0], -sizeof (ip6_header_t));
oh6 = vlib_buffer_get_current (b[0]);
if (ah_hdr_len >= sizeof (ip6_header_t))
clib_memcpy (oh6, b[0]->data + pd->current_data,
sizeof (ip6_header_t));
else
memmove (oh6, b[0]->data + pd->current_data,
sizeof (ip6_header_t));
next[0] = AH_DECRYPT_NEXT_IP6_INPUT;
oh6->protocol = pd->nexthdr;
oh6->hop_limit = pd->hop_limit;
oh6->ip_version_traffic_class_and_flow_label =
pd->ip_version_traffic_class_and_flow_label;
oh6->payload_length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain
(vm, b[0]) - sizeof (ip6_header_t));
}
else
{
vlib_buffer_advance (b[0], -sizeof (ip4_header_t));
oh4 = vlib_buffer_get_current (b[0]);
if (ah_hdr_len >= sizeof (ip4_header_t))
clib_memcpy (oh4, b[0]->data + pd->current_data,
sizeof (ip4_header_t));
else
memmove (oh4, b[0]->data + pd->current_data,
sizeof (ip4_header_t));
next[0] = AH_DECRYPT_NEXT_IP4_INPUT;
oh4->ip_version_and_header_length = 0x45;
oh4->fragment_id = 0;
oh4->flags_and_fragment_offset = 0;
oh4->protocol = pd->nexthdr_cached;
oh4->length =
clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b[0]));
oh4->ttl = pd->ttl;
oh4->tos = pd->tos;
oh4->checksum = ip4_header_checksum (oh4);
}
}
vnet_buffer (b[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
trace:
if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
{
sa0 = pool_elt_at_index (im->sad,
vnet_buffer (b[0])->ipsec.sad_index);
ah_decrypt_trace_t *tr =
vlib_add_trace (vm, node, b[0], sizeof (*tr));
tr->integ_alg = sa0->integ_alg;
tr->seq_num = pd->seq;
}
n_left -= 1;
pd += 1;
next += 1;
b += 1;
}
n_left = from_frame->n_vectors;
vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);
return n_left;
}
VLIB_NODE_FN (ah4_decrypt_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return ah_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ah4_decrypt_node) = {
.name = "ah4-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 = {
[AH_DECRYPT_NEXT_DROP] = "ip4-drop",
[AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[AH_DECRYPT_NEXT_HANDOFF] = "ah4-decrypt-handoff",
},
};
/* *INDENT-ON* */
VLIB_NODE_FN (ah6_decrypt_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return ah_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ah6_decrypt_node) = {
.name = "ah6-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 = {
[AH_DECRYPT_NEXT_DROP] = "ip6-drop",
[AH_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[AH_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[AH_DECRYPT_NEXT_HANDOFF] = "ah6-decrypt-handoff",
},
};
/* *INDENT-ON* */
#ifndef CLIB_MARCH_VARIANT
static clib_error_t *
ah_decrypt_init (vlib_main_t *vm)
{
ipsec_main_t *im = &ipsec_main;
im->ah4_dec_fq_index =
vlib_frame_queue_main_init (ah4_decrypt_node.index, 0);
im->ah6_dec_fq_index =
vlib_frame_queue_main_init (ah6_decrypt_node.index, 0);
return 0;
}
VLIB_INIT_FUNCTION (ah_decrypt_init);
#endif
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/