/* * 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. */ /* * ip/ip4_source_check.c: IP v4 check source address (unicast RPF check) * * Copyright (c) 2008 Eliot Dresselhaus * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include <vnet/ip/ip.h> #include <vnet/fib/ip4_fib.h> #include <vnet/fib/fib_urpf_list.h> #include <vnet/dpo/load_balance.h> /** * @file * @brief IPv4 Unicast Source Check. * * This file contains the IPv4 interface unicast source check. */ typedef struct { u8 packet_data[64]; index_t urpf; } ip4_source_check_trace_t; static u8 * format_ip4_source_check_trace (u8 * s, va_list * va) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *); ip4_source_check_trace_t *t = va_arg (*va, ip4_source_check_trace_t *); s = format (s, "%U", format_ip4_header, t->packet_data, sizeof (t->packet_data)); return s; } typedef enum { IP4_SOURCE_CHECK_NEXT_DROP, IP4_SOURCE_CHECK_N_NEXT, } ip4_source_check_next_t; typedef enum { IP4_SOURCE_CHECK_REACHABLE_VIA_RX, IP4_SOURCE_CHECK_REACHABLE_VIA_ANY, } ip4_source_check_type_t; typedef union { u32 fib_index; } ip4_source_check_config_t; always_inline uword ip4_source_check_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame, ip4_source_check_type_t source_check_type) { u32 n_left_from, *from, *to_next; u32 next_index; vlib_node_runtime_t *error_node = vlib_node_get_runtime (vm, ip4_input_node.index); from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; next_index = node->cached_next_index; if (node->flags & VLIB_NODE_FLAG_TRACE) vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors, /* stride */ 1, sizeof (ip4_source_check_trace_t)); 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 >= 4 && n_left_to_next >= 2) { vlib_buffer_t *p0, *p1; ip4_header_t *ip0, *ip1; ip4_fib_mtrie_t *mtrie0, *mtrie1; ip4_fib_mtrie_leaf_t leaf0, leaf1; ip4_source_check_config_t *c0, *c1; const load_balance_t *lb0, *lb1; u32 pi0, next0, pass0, lb_index0; u32 pi1, next1, pass1, lb_index1; /* Prefetch next iteration. */ { vlib_buffer_t *p2, *p3; p2 = vlib_get_buffer (vm, from[2]); p3 = vlib_get_buffer (vm, from[3]); vlib_prefetch_buffer_header (p2, LOAD); vlib_prefetch_buffer_header (p3, LOAD); CLIB_PREFETCH (p2->data, sizeof (ip0[0]), LOAD); CLIB_PREFETCH (p3->data, sizeof (ip1[0]), LOAD); } pi0 = to_next[0] = from[0]; pi1 = to_next[1] = from[1]; from += 2; to_next += 2; n_left_from -= 2; n_left_to_next -= 2; p0 = vlib_get_buffer (vm, pi0); p1 = vlib_get_buffer (vm, pi1); ip0 = vlib_buffer_get_current (p0); ip1 = vlib_buffer_get_current (p1); c0 = vnet_feature_next_with_data (vnet_buffer (p0)->sw_if_index [VLIB_RX], &next0, p0, sizeof (c0[0])); c1 = vnet_feature_next_with_data (vnet_buffer (p1)->sw_if_index [VLIB_RX], &next1, p1, sizeof (c1[0])); mtrie0 = &ip4_fib_get (c0->fib_index)->mtrie; mtrie1 = &ip4_fib_get (c1->fib_index)->mtrie; leaf0 = ip4_fib_mtrie_lookup_step_one (mtrie0, &ip0->src_address); leaf1 = ip4_fib_mtrie_lookup_step_one (mtrie1, &ip1->src_address); leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 2); leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 2); leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 3); leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 3); lb_index0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0); lb_index1 = ip4_fib_mtrie_leaf_get_adj_index (leaf1); lb0 = load_balance_get (lb_index0); lb1 = load_balance_get (lb_index1); /* Pass multicast. */ pass0 = ip4_address_is_multicast (&ip0->src_address) || ip0->src_address.as_u32 == clib_host_to_net_u32 (0xFFFFFFFF); pass1 = ip4_address_is_multicast (&ip1->src_address) || ip1->src_address.as_u32 == clib_host_to_net_u32 (0xFFFFFFFF); if (IP4_SOURCE_CHECK_REACHABLE_VIA_RX == source_check_type) { pass0 |= fib_urpf_check (lb0->lb_urpf, vnet_buffer (p0)->sw_if_index [VLIB_RX]); pass1 |= fib_urpf_check (lb1->lb_urpf, vnet_buffer (p1)->sw_if_index[VLIB_RX]); } else { pass0 |= fib_urpf_check_size (lb0->lb_urpf); pass1 |= fib_urpf_check_size (lb1->lb_urpf); } next0 = (pass0 ? next0 : IP4_SOURCE_CHECK_NEXT_DROP); next1 = (pass1 ? next1 : IP4_SOURCE_CHECK_NEXT_DROP); p0->error = error_node->errors[IP4_ERROR_UNICAST_SOURCE_CHECK_FAILS]; p1->error = error_node->errors[IP4_ERROR_UNICAST_SOURCE_CHECK_FAILS]; vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next, n_left_to_next, pi0, pi1, next0, next1); } while (n_left_from > 0 && n_left_to_next > 0) { vlib_buffer_t *p0; ip4_header_t *ip0; ip4_fib_mtrie_t *mtrie0; ip4_fib_mtrie_leaf_t leaf0; ip4_source_check_config_t *c0; u32 pi0, next0, pass0, lb_index0; const load_balance_t *lb0; pi0 = from[0]; to_next[0] = pi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; p0 = vlib_get_buffer (vm, pi0); ip0 = vlib_buffer_get_current (p0); c0 = vnet_feature_next_with_data (vnet_buffer (p0)->sw_if_index [VLIB_RX], &next0, p0, sizeof (c0[0])); mtrie0 = &ip4_fib_get (c0->fib_index)->mtrie; leaf0 = ip4_fib_mtrie_lookup_step_one (mtrie0, &ip0->src_address); leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 2); leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 3); lb_index0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0); lb0 = load_balance_get (lb_index0); /* Pass multicast. */ pass0 = ip4_address_is_multicast (&ip0->src_address) || ip0->src_address.as_u32 == clib_host_to_net_u32 (0xFFFFFFFF); if (IP4_SOURCE_CHECK_REACHABLE_VIA_RX == source_check_type) { pass0 |= fib_urpf_check (lb0->lb_urpf, vnet_buffer (p0)->sw_if_index [VLIB_RX]); } else { pass0 |= fib_urpf_check_size (lb0->lb_urpf); } next0 = (pass0 ? next0 : IP4_SOURCE_CHECK_NEXT_DROP); p0->error = error_node->errors[IP4_ERROR_UNICAST_SOURCE_CHECK_FAILS]; vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, pi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return frame->n_vectors; } static uword ip4_source_check_reachable_via_any (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { return ip4_source_check_inline (vm, node, frame, IP4_SOURCE_CHECK_REACHABLE_VIA_ANY); } static uword ip4_source_check_reachable_via_rx (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { return ip4_source_check_inline (vm, node, frame, IP4_SOURCE_CHECK_REACHABLE_VIA_RX); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ip4_check_source_reachable_via_any) = { .function = ip4_source_check_reachable_via_any, .name = "ip4-source-check-via-any", .vector_size = sizeof (u32), .n_next_nodes = IP4_SOURCE_CHECK_N_NEXT, .next_nodes = { [IP4_SOURCE_CHECK_NEXT_DROP] = "error-drop", }, .format_buffer = format_ip4_header, .format_trace = format_ip4_source_check_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (ip4_check_source_reachable_via_any, ip4_source_check_reachable_via_any); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ip4_check_source_reachable_via_rx) = { .function = ip4_source_check_reachable_via_rx, .name = "ip4-source-check-via-rx", .vector_size = sizeof (u32), .n_next_nodes = IP4_SOURCE_CHECK_N_NEXT, .next_nodes = { [IP4_SOURCE_CHECK_NEXT_DROP] = "error-drop", }, .format_buffer = format_ip4_header, .format_trace = format_ip4_source_check_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (ip4_check_source_reachable_via_rx, ip4_source_check_reachable_via_rx); static clib_error_t * set_ip_source_check (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { unformat_input_t _line_input, *line_input = &_line_input; vnet_main_t *vnm = vnet_get_main (); ip4_main_t *im = &ip4_main; clib_error_t *error = 0; u32 sw_if_index, is_del; ip4_source_check_config_t config; char *feature_name = "ip4-source-check-via-rx"; sw_if_index = ~0; is_del = 0; if (!unformat_user (input, unformat_line_input, line_input)) return 0; while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT) { if (unformat_user (line_input, unformat_vnet_sw_interface, vnm, &sw_if_index)) ; else if (unformat (line_input, "del")) is_del = 1; else if (unformat (line_input, "loose")) feature_name = "ip4-source-check-via-any"; else { error = unformat_parse_error (line_input); goto done; } } if (~0 == sw_if_index) { error = clib_error_return (0, "unknown interface `%U'", format_unformat_error, line_input); goto done; } config.fib_index = im->fib_index_by_sw_if_index[sw_if_index]; vnet_feature_enable_disable ("ip4-unicast", feature_name, sw_if_index, is_del == 0, &config, sizeof (config)); done: unformat_free (line_input); return error; } /*? * This command adds the 'ip4-source-check-via-rx' graph node for * a given interface. By adding the IPv4 source check graph node to * an interface, the code verifies that the source address of incoming * unicast packets are reachable over the incoming interface. Two flavours * are supported (the default is strict): * - loose: accept ingress packet if there is a route to reach the source * - strict: accept ingress packet if it arrived on an interface which * the route to the source uses. i.e. an interface that the source * is reachable via. * * @cliexpar * @parblock * Example of graph node before range checking is enabled: * @cliexstart{show vlib graph ip4-source-check-via-rx} * Name Next Previous * ip4-source-check-via-rx error-drop [0] * @cliexend * * Example of how to enable unicast source checking on an interface: * @cliexcmd{set interface ip source-check GigabitEthernet2/0/0 loose} * * Example of graph node after range checking is enabled: * @cliexstart{show vlib graph ip4-source-check-via-rx} * Name Next Previous * ip4-source-check-via-rx error-drop [0] ip4-input-no-checksum * ip4-source-and-port-range- ip4-input * @cliexend * * Example of how to display the feature enabed on an interface: * @cliexstart{show ip interface features GigabitEthernet2/0/0} * IP feature paths configured on GigabitEthernet2/0/0... * * ipv4 unicast: * ip4-source-check-via-rx * ip4-lookup * * ipv4 multicast: * ip4-lookup-multicast * * ipv4 multicast: * interface-output * * ipv6 unicast: * ip6-lookup * * ipv6 multicast: * ip6-lookup * * ipv6 multicast: * interface-output * @cliexend * * Example of how to disable unicast source checking on an interface: * @cliexcmd{set interface ip source-check GigabitEthernet2/0/0 del} * @endparblock ?*/ /* *INDENT-OFF* */ VLIB_CLI_COMMAND (set_interface_ip_source_check_command, static) = { .path = "set interface ip source-check", .function = set_ip_source_check, .short_help = "set interface ip source-check <interface> [strict|loose] [del]", }; /* *INDENT-ON* */ static clib_error_t * ip_source_check_accept (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { unformat_input_t _line_input, *line_input = &_line_input; fib_prefix_t pfx = { .fp_proto = FIB_PROTOCOL_IP4, }; clib_error_t *error = NULL; u32 table_id, is_add, fib_index; is_add = 1; table_id = ~0; /* Get a line of input. */ if (!unformat_user (input, unformat_line_input, line_input)) return 0; while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT) { if (unformat (line_input, "table %d", &table_id)) ; else if (unformat (line_input, "del")) is_add = 0; else if (unformat (line_input, "add")) is_add = 1; else if (unformat (line_input, "%U/%d", unformat_ip4_address, &pfx.fp_addr.ip4, &pfx.fp_len)) pfx.fp_proto = FIB_PROTOCOL_IP4; else { error = unformat_parse_error (line_input); goto done; } } if (~0 != table_id) { fib_index = fib_table_find (pfx.fp_proto, table_id); if (~0 == fib_index) { error = clib_error_return (0, "Nonexistent table id %d", table_id); goto done; } } else { fib_index = 0; } if (is_add) { fib_table_entry_special_add (fib_index, &pfx, FIB_SOURCE_URPF_EXEMPT, FIB_ENTRY_FLAG_DROP); } else { fib_table_entry_special_remove (fib_index, &pfx, FIB_SOURCE_URPF_EXEMPT); } done: unformat_free (line_input); return error; } /*? * Add an exemption for a prefix to pass the Unicast Reverse Path * Forwarding (uRPF) loose check. This is for testing purposes only. * If the '<em>table</em>' is not enter it is defaulted to 0. Default * is to '<em>add</em>'. VPP always performs a loose uRPF check for * for-us traffic. * * @cliexpar * Example of how to add a uRPF exception to a FIB table to pass the * loose RPF tests: * @cliexcmd{ip urpf-accept table 7 add} ?*/ /* *INDENT-OFF* */ VLIB_CLI_COMMAND (ip_source_check_accept_command, static) = { .path = "ip urpf-accept", .function = ip_source_check_accept, .short_help = "ip urpf-accept [table <table-id>] [add|del]", }; /* *INDENT-ON* */ /* Dummy init function to get us linked in. */ clib_error_t * ip4_source_check_init (vlib_main_t * vm) { return 0; } VLIB_INIT_FUNCTION (ip4_source_check_init); /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */