/* * Copyright (c) 2020 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 <urpf/urpf.h> #include <vnet/fib/fib_table.h> /* *INDENT-OFF* */ static const char *urpf_feat_arcs[N_AF][VLIB_N_DIR] = { [AF_IP4] = { [VLIB_RX] = "ip4-unicast", [VLIB_TX] = "ip4-output", }, [AF_IP6] = { [VLIB_RX] = "ip6-unicast", [VLIB_TX] = "ip6-output", }, }; static const char *urpf_feats[N_AF][VLIB_N_DIR][URPF_N_MODES] = { [AF_IP4] = { [VLIB_RX] = { [URPF_MODE_STRICT] = "ip4-rx-urpf-strict", [URPF_MODE_LOOSE] = "ip4-rx-urpf-loose", }, [VLIB_TX] = { [URPF_MODE_STRICT] = "ip4-tx-urpf-strict", [URPF_MODE_LOOSE] = "ip4-tx-urpf-loose", }, }, [AF_IP6] = { [VLIB_RX] = { [URPF_MODE_STRICT] = "ip6-rx-urpf-strict", [URPF_MODE_LOOSE] = "ip6-rx-urpf-loose", }, [VLIB_TX] = { [URPF_MODE_STRICT] = "ip6-tx-urpf-strict", [URPF_MODE_LOOSE] = "ip6-tx-urpf-loose", }, }, }; /* *INDENT-ON* */ /** * Per-af, per-direction, per-interface uRPF configs */ static urpf_mode_t *urpf_cfgs[N_AF][VLIB_N_DIR]; u8 * format_urpf_mode (u8 * s, va_list * a) { urpf_mode_t mode = va_arg (*a, int); switch (mode) { #define _(a,b) \ case URPF_MODE_##a: \ return (format (s, "%s", b)); foreach_urpf_mode #undef _ } return (format (s, "unknown")); } static uword unformat_urpf_mode (unformat_input_t * input, va_list * args) { urpf_mode_t *mode = va_arg (*args, urpf_mode_t *); if (0) ; #define _(a,b) \ else if (unformat (input, b)) \ { \ *mode = URPF_MODE_##a; \ return (1); \ } foreach_urpf_mode #undef _ return 0; } void urpf_update (urpf_mode_t mode, u32 sw_if_index, ip_address_family_t af, vlib_dir_t dir) { urpf_mode_t old; vec_validate_init_empty (urpf_cfgs[af][dir], sw_if_index, URPF_MODE_OFF); old = urpf_cfgs[af][dir][sw_if_index]; if (mode != old) { if (URPF_MODE_OFF != old) /* disable what we have */ vnet_feature_enable_disable (urpf_feat_arcs[af][dir], urpf_feats[af][dir][old], sw_if_index, 0, 0, 0); if (URPF_MODE_OFF != mode) /* enable what's new */ vnet_feature_enable_disable (urpf_feat_arcs[af][dir], urpf_feats[af][dir][mode], sw_if_index, 1, 0, 0); } /* else - no change to existing config */ urpf_cfgs[af][dir][sw_if_index] = mode; } static clib_error_t * urpf_cli_update (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 (); clib_error_t *error = NULL; ip_address_family_t af; urpf_mode_t mode; u32 sw_if_index; vlib_dir_t dir; sw_if_index = ~0; af = AF_IP4; dir = VLIB_RX; mode = URPF_MODE_STRICT; 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, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index)) ; else if (unformat (line_input, "%U", unformat_urpf_mode, &mode)) ; else if (unformat (line_input, "%U", unformat_ip_address_family, &af)) ; else if (unformat (line_input, "%U", unformat_vlib_rx_tx, &dir)) ; 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; } urpf_update (mode, sw_if_index, af, dir); done: unformat_free (line_input); return error; } /*? * This command configures uRPF on an 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-rx-urpf-strict} * Name Next Previous * ip4-rx-urpf-strict ip4-drop [0] * @cliexend * * Example of how to enable unicast source checking on an interface: * @cliexcmd{set urpf ip4 rx GigabitEthernet2/0/0 loose} * * Example of graph node after range checking is enabled: * @cliexstart{show vlib graph ip4-rx-urpf-loose} * Name Next Previous * ip4-rx-urpf-loose ip4-drop [0] ip4-input-no-checksum * ip4-source-and-port-range- ip4-input * @cliexend * * Example of how to display the feature enabled on an interface: * @cliexstart{show ip interface features GigabitEthernet2/0/0} * IP feature paths configured on GigabitEthernet2/0/0... * * ipv4 unicast: * ip4-rx-urpf-loose * 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 urpf ip4 off GigabitEthernet2/0/0} * @endparblock ?*/ /* *INDENT-OFF* */ VLIB_CLI_COMMAND (set_interface_ip_source_check_command, static) = { .path = "set urpf", .function = urpf_cli_update, .short_help = "set urpf [ip4|ip6] [rx|tx] [off|strict|loose] <INTERFACE>", }; /* *INDENT-ON* */ static clib_error_t * urpf_cli_accept (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { unformat_input_t _line_input, *line_input = &_line_input; clib_error_t *error = NULL; fib_prefix_t fpfx; ip_prefix_t pfx; 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", unformat_ip_prefix, &pfx)) ; else { error = unformat_parse_error (line_input); goto done; } } ip_prefix_to_fib_prefix (&pfx, &fpfx); fib_index = fib_table_find (fpfx.fp_proto, table_id); if (~0 == fib_index) { error = clib_error_return (0, "Nonexistent table id %d", table_id); goto done; } if (is_add) fib_table_entry_special_add (fib_index, &fpfx, FIB_SOURCE_URPF_EXEMPT, FIB_ENTRY_FLAG_DROP); else fib_table_entry_special_remove (fib_index, &fpfx, 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{set urpf-accept table 7 10.0.0.0/8 add} ?*/ /* *INDENT-OFF* */ VLIB_CLI_COMMAND (urpf_accept_command, static) = { .path = "set urpf-accept", .function = urpf_cli_accept, .short_help = "urpf-accept [table <table-id>] [add|del] <PREFIX>", }; /* *INDENT-ON* */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */