diff options
Diffstat (limited to 'src/vnet')
| -rw-r--r-- | src/vnet/CMakeLists.txt | 2 | ||||
| -rw-r--r-- | src/vnet/ip/icmp4.c | 26 | ||||
| -rw-r--r-- | src/vnet/ip/icmp6.c | 21 | ||||
| -rw-r--r-- | src/vnet/ip/ip_sas.c | 214 | ||||
| -rw-r--r-- | src/vnet/ip/ip_sas.h | 32 |
5 files changed, 261 insertions, 34 deletions
diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt index 66a4abc3a41..18e162030b0 100644 --- a/src/vnet/CMakeLists.txt +++ b/src/vnet/CMakeLists.txt @@ -73,6 +73,7 @@ list(APPEND VNET_HEADERS util/refcount.h format_fns.h ip/ip_format_fns.h + ip/ip_sas.h ethernet/ethernet_format_fns.h ) @@ -413,6 +414,7 @@ list(APPEND VNET_SOURCES ip/punt.c ip/punt_node.c ip/vtep.c + ip/ip_sas.c ) list(APPEND VNET_MULTIARCH_SOURCES diff --git a/src/vnet/ip/icmp4.c b/src/vnet/ip/icmp4.c index 0363092d5d5..5f9ffa3b2b7 100644 --- a/src/vnet/ip/icmp4.c +++ b/src/vnet/ip/icmp4.c @@ -40,6 +40,7 @@ #include <vlib/vlib.h> #include <vnet/ip/ip.h> #include <vnet/pg/pg.h> +#include <vnet/ip/ip_sas.h> static char *icmp_error_strings[] = { #define _(f,s) s, @@ -254,8 +255,6 @@ ip4_icmp_error (vlib_main_t * vm, u32 *from, *to_next; uword n_left_from, n_left_to_next; ip4_icmp_error_next_t next_index; - ip4_main_t *im = &ip4_main; - ip_lookup_main_t *lm = &im->lookup_main; from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; @@ -286,7 +285,7 @@ ip4_icmp_error (vlib_main_t * vm, vlib_buffer_t *p0, *org_p0; ip4_header_t *ip0, *out_ip0; icmp46_header_t *icmp0; - u32 sw_if_index0, if_add_index0; + u32 sw_if_index0; ip_csum_t sum; org_p0 = vlib_get_buffer (vm, org_pi0); @@ -323,25 +322,14 @@ ip4_icmp_error (vlib_main_t * vm, out_ip0->ttl = 0xff; out_ip0->protocol = IP_PROTOCOL_ICMP; out_ip0->dst_address = ip0->src_address; - if_add_index0 = ~0; - if (PREDICT_TRUE (vec_len (lm->if_address_pool_index_by_sw_if_index) - > sw_if_index0)) - if_add_index0 = - lm->if_address_pool_index_by_sw_if_index[sw_if_index0]; - if (PREDICT_TRUE (if_add_index0 != ~0)) - { - ip_interface_address_t *if_add = - pool_elt_at_index (lm->if_address_pool, if_add_index0); - ip4_address_t *if_ip = - ip_interface_address_get_address (lm, if_add); - out_ip0->src_address = *if_ip; - } - else - { - /* interface has no IP4 address - should not happen */ + /* Prefer a source address from "offending interface" */ + if (!ip4_sas_by_sw_if_index (sw_if_index0, &out_ip0->dst_address, + &out_ip0->src_address)) + { /* interface has no IP6 address - should not happen */ next0 = IP4_ICMP_ERROR_NEXT_DROP; error0 = ICMP4_ERROR_DROP; } + out_ip0->checksum = ip4_header_checksum (out_ip0); /* Fill icmp header fields */ diff --git a/src/vnet/ip/icmp6.c b/src/vnet/ip/icmp6.c index 4bba430fadc..b6ed3ea0ec9 100644 --- a/src/vnet/ip/icmp6.c +++ b/src/vnet/ip/icmp6.c @@ -40,6 +40,7 @@ #include <vlib/vlib.h> #include <vnet/ip/ip.h> #include <vnet/pg/pg.h> +#include <vnet/ip/ip_sas.h> static u8 * format_ip6_icmp_type_and_code (u8 * s, va_list * args) @@ -475,8 +476,6 @@ ip6_icmp_error (vlib_main_t * vm, u32 *from, *to_next; uword n_left_from, n_left_to_next; ip6_icmp_error_next_t next_index; - ip6_main_t *im = &ip6_main; - ip_lookup_main_t *lm = &im->lookup_main; from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; @@ -507,7 +506,7 @@ ip6_icmp_error (vlib_main_t * vm, vlib_buffer_t *p0, *org_p0; ip6_header_t *ip0, *out_ip0; icmp46_header_t *icmp0; - u32 sw_if_index0, if_add_index0; + u32 sw_if_index0; int bogus_length; org_p0 = vlib_get_buffer (vm, org_pi0); @@ -547,18 +546,10 @@ ip6_icmp_error (vlib_main_t * vm, out_ip0->protocol = IP_PROTOCOL_ICMP6; out_ip0->hop_limit = 0xff; out_ip0->dst_address = ip0->src_address; - if_add_index0 = - lm->if_address_pool_index_by_sw_if_index[sw_if_index0]; - if (PREDICT_TRUE (if_add_index0 != ~0)) - { - ip_interface_address_t *if_add = - pool_elt_at_index (lm->if_address_pool, if_add_index0); - ip6_address_t *if_ip = - ip_interface_address_get_address (lm, if_add); - out_ip0->src_address = *if_ip; - } - else /* interface has no IP6 address - should not happen */ - { + /* Prefer a source address from "offending interface" */ + if (!ip6_sas_by_sw_if_index (sw_if_index0, &out_ip0->dst_address, + &out_ip0->src_address)) + { /* interface has no IP6 address - should not happen */ next0 = IP6_ICMP_ERROR_NEXT_DROP; error0 = ICMP6_ERROR_DROP; } diff --git a/src/vnet/ip/ip_sas.c b/src/vnet/ip/ip_sas.c new file mode 100644 index 00000000000..7d3632d95ed --- /dev/null +++ b/src/vnet/ip/ip_sas.c @@ -0,0 +1,214 @@ +/* + * Copyright (c) 2021 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 "ip_sas.h" +#include <vppinfra/types.h> +#include <vnet/ip/ip_interface.h> +#include <vnet/fib/fib_table.h> +#include <vnet/ip/ip6_link.h> +#include <vppinfra/byte_order.h> + +/* + * This file implement source address selection for VPP applications + * (e.g. ping, DNS, ICMP) + * It does not yet implement full fledged RFC6724 SAS. + * SAS assumes every IP enabled interface has an address. The algorithm will + * not go and hunt for a suitable IP address on other interfaces than the + * output interface or the specified preferred sw_if_index. + * That means that an interface with just an IPv6 link-local address must also + * be configured with an unnumbered configuration pointing to a numbered + * interface. + */ + +static int +ip6_sas_commonlen (const ip6_address_t *a1, const ip6_address_t *a2) +{ + u64 fa = clib_net_to_host_u64 (a1->as_u64[0]) ^ + clib_net_to_host_u64 (a2->as_u64[0]); + if (fa == 0) + { + u64 la = clib_net_to_host_u64 (a1->as_u64[1]) ^ + clib_net_to_host_u64 (a2->as_u64[1]); + if (la == 0) + return 128; + return 64 + __builtin_clzll (la); + } + else + { + return __builtin_clzll (fa); + } +} + +static int +ip4_sas_commonlen (const ip4_address_t *a1, const ip4_address_t *a2) +{ + u64 a = + clib_net_to_host_u32 (a1->as_u32) ^ clib_net_to_host_u32 (a2->as_u32); + if (a == 0) + return 32; + return __builtin_clz (a); +} + +/* + * walk all addresses on an interface: + * - prefer a source matching the scope of the destination address. + * - last resort pick the source address with the longest + * common prefix with destination + * NOTE: This should at some point implement RFC6724. + */ +bool +ip6_sas_by_sw_if_index (u32 sw_if_index, const ip6_address_t *dst, + ip6_address_t *src) +{ + ip_interface_address_t *ia = 0; + ip_lookup_main_t *lm6 = &ip6_main.lookup_main; + ip6_address_t *tmp, *bestsrc = 0; + int bestlen = 0, l; + + if (ip6_address_is_link_local_unicast (dst) || + dst->as_u32[0] == clib_host_to_net_u32 (0xff020000)) + { + ip6_address_copy (src, ip6_get_link_local_address (sw_if_index)); + return true; + } + + foreach_ip_interface_address ( + lm6, ia, sw_if_index, 1, ({ + if (ia->flags & IP_INTERFACE_ADDRESS_FLAG_STALE) + continue; + tmp = ip_interface_address_get_address (lm6, ia); + l = ip6_sas_commonlen (tmp, dst); + if (l > bestlen || bestsrc == 0) + { + bestsrc = tmp; + bestlen = l; + } + })); + if (bestsrc) + { + ip6_address_copy (src, bestsrc); + return true; + } + return false; +} + +/* + * walk all addresses on an interface and pick the source address with the + * longest common prefix with destination. + */ +bool +ip4_sas_by_sw_if_index (u32 sw_if_index, const ip4_address_t *dst, + ip4_address_t *src) +{ + ip_interface_address_t *ia = 0; + ip_lookup_main_t *lm4 = &ip4_main.lookup_main; + ip4_address_t *tmp, *bestsrc = 0; + int bestlen = 0, l; + + foreach_ip_interface_address ( + lm4, ia, sw_if_index, 1, ({ + if (ia->flags & IP_INTERFACE_ADDRESS_FLAG_STALE) + continue; + tmp = ip_interface_address_get_address (lm4, ia); + l = ip4_sas_commonlen (tmp, dst); + if (l > bestlen || bestsrc == 0) + { + bestsrc = tmp; + bestlen = l; + } + })); + if (bestsrc) + { + src->as_u32 = bestsrc->as_u32; + return true; + } + return false; +} + +/* + * table_id must be set. Default = 0. + * sw_if_index is the interface to pick SA from otherwise ~0 will pick from + * outbound interface. + * + * NOTE: What to do if multiple output interfaces? + * + */ +bool +ip6_sas (u32 table_id, u32 sw_if_index, const ip6_address_t *dst, + ip6_address_t *src) +{ + fib_prefix_t prefix; + u32 if_index = sw_if_index; + + /* If sw_if_index is not specified use the output interface. */ + if (sw_if_index == ~0) + { + clib_memcpy (&prefix.fp_addr.ip6, dst, sizeof (*dst)); + prefix.fp_proto = FIB_PROTOCOL_IP6; + prefix.fp_len = 128; + + u32 fib_index = fib_table_find (prefix.fp_proto, table_id); + if (fib_index == (u32) ~0) + return false; + + fib_node_index_t fei = fib_table_lookup (fib_index, &prefix); + if (fei == FIB_NODE_INDEX_INVALID) + return false; + + u32 output_sw_if_index = fib_entry_get_resolving_interface (fei); + if (output_sw_if_index == ~0) + return false; + if_index = output_sw_if_index; + } + return ip6_sas_by_sw_if_index (if_index, dst, src); +} + +/* + * table_id must be set. Default = 0. + * sw_if_index is the interface to pick SA from otherwise ~0 will pick from + * outbound interface. + * + * NOTE: What to do if multiple output interfaces? + * + */ +bool +ip4_sas (u32 table_id, u32 sw_if_index, const ip4_address_t *dst, + ip4_address_t *src) +{ + fib_prefix_t prefix; + u32 if_index = sw_if_index; + + /* If sw_if_index is not specified use the output interface. */ + if (sw_if_index == ~0) + { + clib_memcpy (&prefix.fp_addr.ip4, dst, sizeof (*dst)); + prefix.fp_proto = FIB_PROTOCOL_IP4; + prefix.fp_len = 32; + + u32 fib_index = fib_table_find (prefix.fp_proto, table_id); + if (fib_index == (u32) ~0) + return false; + + fib_node_index_t fei = fib_table_lookup (fib_index, &prefix); + if (fei == FIB_NODE_INDEX_INVALID) + return false; + + u32 output_sw_if_index = fib_entry_get_resolving_interface (fei); + if (output_sw_if_index == ~0) + return false; + if_index = output_sw_if_index; + } + return ip4_sas_by_sw_if_index (if_index, dst, src); +} diff --git a/src/vnet/ip/ip_sas.h b/src/vnet/ip/ip_sas.h new file mode 100644 index 00000000000..b1e9e732ed9 --- /dev/null +++ b/src/vnet/ip/ip_sas.h @@ -0,0 +1,32 @@ +/* + * Copyright (c) 2021 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. + */ + +#ifndef included_ip_sas_h +#define included_ip_sas_h + +#include <stdbool.h> +#include <vnet/ip/ip6_packet.h> +#include <vnet/ip/ip4_packet.h> + +bool ip6_sas_by_sw_if_index (u32 sw_if_index, const ip6_address_t *dst, + ip6_address_t *src); +bool ip4_sas_by_sw_if_index (u32 sw_if_index, const ip4_address_t *dst, + ip4_address_t *src); +bool ip6_sas (u32 table_id, u32 sw_if_index, const ip6_address_t *dst, + ip6_address_t *src); +bool ip4_sas (u32 table_id, u32 sw_if_index, const ip4_address_t *dst, + ip4_address_t *src); + +#endif |