/* * 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->decrypt_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->decrypt_thread_index, ~0, ipsec_sa_assign_thread (thread_index)); } if (PREDICT_TRUE (thread_index != sa0->decrypt_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* */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */