From a55df1081762b4e40698ef7d9196551851be646a Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Wed, 6 Mar 2019 11:14:03 -0500 Subject: ipv6 connection tracking plugin A security feature: drop unsolicited global unicast traffic. Change-Id: I421da7d52e08b7acf40c62a1f6e2a6caac349e7e Signed-off-by: Dave Barach --- src/plugins/ct6/ct6_in2out.c | 362 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 src/plugins/ct6/ct6_in2out.c (limited to 'src/plugins/ct6/ct6_in2out.c') diff --git a/src/plugins/ct6/ct6_in2out.c b/src/plugins/ct6/ct6_in2out.c new file mode 100644 index 00000000000..b28d349dd29 --- /dev/null +++ b/src/plugins/ct6/ct6_in2out.c @@ -0,0 +1,362 @@ +/* + * ct6_in2out.c - ip6 connection tracker, inside-to-outside path + * + * Copyright (c) 2019 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 +#include +#include +#include +#include + +typedef struct +{ + u32 sw_if_index; + u32 next_index; + u32 session_index; +} ct6_in2out_trace_t; + +#ifndef CLIB_MARCH_VARIANT + +/* packet trace format function */ +static u8 * +format_ct6_in2out_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 *); + ct6_in2out_trace_t *t = va_arg (*args, ct6_in2out_trace_t *); + + s = format (s, "CT6_IN2OUT: sw_if_index %d, next index %d session %d\n", + t->sw_if_index, t->next_index, t->session_index); + return s; +} + +vlib_node_registration_t ct6_in2out_node; + +#endif /* CLIB_MARCH_VARIANT */ + +#define foreach_ct6_in2out_error \ +_(PROCESSED, "ct6 packets processed") \ +_(CREATED, "ct6 sessions created") \ +_(RECYCLED, "ct6 sessions recycled") + +typedef enum +{ +#define _(sym,str) CT6_IN2OUT_ERROR_##sym, + foreach_ct6_in2out_error +#undef _ + CT6_IN2OUT_N_ERROR, +} ct6_in2out_error_t; + +#ifndef CLIB_MARCH_VARIANT +static char *ct6_in2out_error_strings[] = { +#define _(sym,string) string, + foreach_ct6_in2out_error +#undef _ +}; +#endif /* CLIB_MARCH_VARIANT */ + +typedef enum +{ + CT6_IN2OUT_NEXT_DROP, + CT6_IN2OUT_N_NEXT, +} ct6_next_t; + +#ifndef CLIB_MARCH_VARIANT +ct6_session_t * +ct6_create_or_recycle_session (ct6_main_t * cmp, + clib_bihash_kv_48_8_t * kvpp, f64 now, + u32 my_thread_index, u32 * recyclep, + u32 * createp) +{ + ct6_session_t *s0; + + /* Empty arena? */ + if (PREDICT_FALSE (cmp->last_index[my_thread_index] == ~0)) + goto alloc0; + + /* Look at the least-recently-used session */ + s0 = pool_elt_at_index (cmp->sessions[my_thread_index], + cmp->last_index[my_thread_index]); + + if (s0->expires < now) + clib_warning ("session %d expired %.2f time now %.2f", + s0 - cmp->sessions[my_thread_index], s0->expires, now); + + if (pool_elts (cmp->sessions[my_thread_index]) >= + cmp->max_sessions_per_worker) + clib_warning ("recycle session %d have %d max %d", + s0 - cmp->sessions[my_thread_index], + pool_elts (cmp->sessions[my_thread_index]), + cmp->max_sessions_per_worker); + + /* Session expired, or we have as many sessions as is allowed by law? */ + if ((s0->expires < now) || (pool_elts (cmp->sessions[my_thread_index]) + >= cmp->max_sessions_per_worker)) + { + /* recycle the session */ + if (clib_bihash_add_del_48_8 (&cmp->session_hash, + (clib_bihash_kv_48_8_t *) s0, + 0 /* is_add */ ) < 0) + clib_warning ("session %d not found in hash?", + s0 - cmp->sessions[my_thread_index]); + + ct6_lru_remove (cmp, s0); + *recyclep += 1; + } + else + { + alloc0: + /* Allocate a fresh session */ + pool_get (cmp->sessions[my_thread_index], s0); + *createp += 1; + } + + /* Sesison setup */ + memset (s0, 0, sizeof (*s0)); + clib_memcpy_fast (s0, kvpp, sizeof (ct6_session_key_t)); + s0->thread_index = my_thread_index; + s0->expires = now + cmp->session_timeout_interval; + kvpp->value = s0 - cmp->sessions[my_thread_index]; + clib_bihash_add_del_48_8 (&cmp->session_hash, kvpp, 1 /* is_add */ ); + ct6_lru_add (cmp, s0, now); + return s0; +} +#endif /* CLIB_MARCH_VARIANT */ + +always_inline uword +ct6_in2out_inline (vlib_main_t * vm, + vlib_node_runtime_t * node, vlib_frame_t * frame, + int is_trace) +{ + u32 n_left_from, *from; + vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b; + u16 nexts[VLIB_FRAME_SIZE], *next; + ct6_main_t *cmp = &ct6_main; + u32 my_thread_index = vm->thread_index; + f64 now = vlib_time_now (vm); + u32 created = 0; + u32 recycled = 0; + + from = vlib_frame_vector_args (frame); + n_left_from = frame->n_vectors; + + vlib_get_buffers (vm, from, bufs, n_left_from); + b = bufs; + next = nexts; + +#if 0 + while (n_left_from >= 4) + { + /* Prefetch next iteration. */ + if (PREDICT_TRUE (n_left_from >= 8)) + { + vlib_prefetch_buffer_header (b[4], STORE); + vlib_prefetch_buffer_header (b[5], STORE); + vlib_prefetch_buffer_header (b[6], STORE); + vlib_prefetch_buffer_header (b[7], STORE); + CLIB_PREFETCH (b[4]->data, CLIB_CACHE_LINE_BYTES, STORE); + CLIB_PREFETCH (b[5]->data, CLIB_CACHE_LINE_BYTES, STORE); + CLIB_PREFETCH (b[6]->data, CLIB_CACHE_LINE_BYTES, STORE); + CLIB_PREFETCH (b[7]->data, CLIB_CACHE_LINE_BYTES, STORE); + } + + /* $$$$ process 4x pkts right here */ + next[0] = 0; + next[1] = 0; + next[2] = 0; + next[3] = 0; + + if (is_trace) + { + if (b[0]->flags & VLIB_BUFFER_IS_TRACED) + { + ct6_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t)); + t->next_index = next[0]; + t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX]; + } + if (b[1]->flags & VLIB_BUFFER_IS_TRACED) + { + ct6_trace_t *t = vlib_add_trace (vm, node, b[1], sizeof (*t)); + t->next_index = next[1]; + t->sw_if_index = vnet_buffer (b[1])->sw_if_index[VLIB_RX]; + } + if (b[2]->flags & VLIB_BUFFER_IS_TRACED) + { + ct6_trace_t *t = vlib_add_trace (vm, node, b[2], sizeof (*t)); + t->next_index = next[2]; + t->sw_if_index = vnet_buffer (b[2])->sw_if_index[VLIB_RX]; + } + if (b[3]->flags & VLIB_BUFFER_IS_TRACED) + { + ct6_trace_t *t = vlib_add_trace (vm, node, b[3], sizeof (*t)); + t->next_index = next[3]; + t->sw_if_index = vnet_buffer (b[3])->sw_if_index[VLIB_RX]; + } + } + + b += 4; + next += 4; + n_left_from -= 4; + } +#endif + + while (n_left_from > 0) + { + clib_bihash_kv_48_8_t kvp0; + ct6_session_key_t *key0; + ct6_session_t *s0; + u32 session_index0 = ~0; + u32 next0, delta0; + ethernet_header_t *e0; + + ip6_header_t *ip0; + udp_header_t *udp0; + + /* $$$ Set to 0 for pg testing */ + if (1) + { + vnet_feature_next (&next0, b[0]); + next[0] = next0; + } + else + next[0] = CT6_IN2OUT_NEXT_DROP; + + /* + * This is an output feature which runs at the last possible + * moment. Assume an ethernet header. + */ + + e0 = vlib_buffer_get_current (b[0]); + delta0 = sizeof (*e0); + delta0 += (e0->type == clib_net_to_host_u16 (ETHERNET_TYPE_VLAN)) + ? 4 : 0; + delta0 += (e0->type == clib_net_to_host_u16 (ETHERNET_TYPE_DOT1AD)) + ? 8 : 0; + + ip0 = (ip6_header_t *) (vlib_buffer_get_current (b[0]) + delta0); + + /* + * Pass non-global unicast traffic + */ + if (PREDICT_FALSE (!ip6_address_is_global_unicast (&ip0->src_address) + || + !ip6_address_is_global_unicast (&ip0->src_address))) + goto trace0; + /* Pass non-udp, non-tcp traffic */ + if (PREDICT_FALSE (ip0->protocol != IP_PROTOCOL_TCP && + ip0->protocol != IP_PROTOCOL_UDP)) + goto trace0; + + udp0 = ip6_next_header (ip0); + + /* + * See if we know about this flow. + * Key set up for the out2in path, the performant case + */ + key0 = (ct6_session_key_t *) & kvp0; + clib_memcpy_fast (&key0->src, &ip0->dst_address, + sizeof (ip6_address_t)); + clib_memcpy_fast (&key0->dst, &ip0->src_address, + sizeof (ip6_address_t)); + key0->as_u64[4] = 0; + key0->as_u64[5] = 0; + key0->sport = udp0->dst_port; + key0->dport = udp0->src_port; + key0->proto = ip0->protocol; + + /* Need to create a new session? */ + if (clib_bihash_search_48_8 (&cmp->session_hash, &kvp0, &kvp0) < 0) + { + s0 = + ct6_create_or_recycle_session (cmp, &kvp0, now, my_thread_index, + &recycled, &created); + session_index0 = kvp0.value; + } + else + { + s0 = pool_elt_at_index (cmp->sessions[my_thread_index], kvp0.value); + session_index0 = kvp0.value; + ct6_update_session_hit (cmp, s0, now); + } + + trace0: + if (is_trace) + { + if (b[0]->flags & VLIB_BUFFER_IS_TRACED) + { + ct6_in2out_trace_t *t = + vlib_add_trace (vm, node, b[0], sizeof (*t)); + t->next_index = next[0]; + t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX]; + t->session_index = session_index0; + } + } + + b += 1; + next += 1; + n_left_from -= 1; + } + + vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors); + + vlib_node_increment_counter (vm, node->node_index, + CT6_IN2OUT_ERROR_PROCESSED, frame->n_vectors); + vlib_node_increment_counter (vm, node->node_index, + CT6_IN2OUT_ERROR_CREATED, created); + vlib_node_increment_counter (vm, node->node_index, + CT6_IN2OUT_ERROR_RECYCLED, recycled); + + return frame->n_vectors; +} + +VLIB_NODE_FN (ct6_in2out_node) (vlib_main_t * vm, vlib_node_runtime_t * node, + vlib_frame_t * frame) +{ + if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE)) + return ct6_in2out_inline (vm, node, frame, 1 /* is_trace */ ); + else + return ct6_in2out_inline (vm, node, frame, 0 /* is_trace */ ); +} + +/* *INDENT-OFF* */ +#ifndef CLIB_MARCH_VARIANT +VLIB_REGISTER_NODE (ct6_in2out_node) = +{ + .name = "ct6-in2out", + .vector_size = sizeof (u32), + .format_trace = format_ct6_in2out_trace, + .type = VLIB_NODE_TYPE_INTERNAL, + + .n_errors = ARRAY_LEN(ct6_in2out_error_strings), + .error_strings = ct6_in2out_error_strings, + + .n_next_nodes = CT6_IN2OUT_N_NEXT, + + /* edit / add dispositions here */ + .next_nodes = { + [CT6_IN2OUT_NEXT_DROP] = "error-drop", + }, + .unformat_buffer = unformat_ethernet_header, +}; +#endif /* CLIB_MARCH_VARIANT */ +/* *INDENT-ON* */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ -- cgit 1.2.3-korg