// SPDX-License-Identifier: Apache-2.0 // Copyright(c) 2023 Cisco Systems, Inc. /* * npt66.c: NPT66 plugin * An implementation of Network Prefix Translation for IPv6-to-IPv6 (NPTv6) as * specified in RFC6296. */ #include <stdio.h> #include <stdint.h> #include <inttypes.h> #include <vlib/vlib.h> #include <vnet/feature/feature.h> #include <vppinfra/pool.h> #include "npt66.h" static int npt66_feature_enable_disable (u32 sw_if_index, bool is_add) { if (vnet_feature_enable_disable ("ip6-unicast", "npt66-input", sw_if_index, is_add, 0, 0) != 0) return -1; if (vnet_feature_enable_disable ("ip6-output", "npt66-output", sw_if_index, is_add, 0, 0) != 0) return -1; return 0; } static void ipv6_prefix_zero (ip6_address_t *address, int prefix_len) { int byte_index = prefix_len / 8; int bit_offset = prefix_len % 8; uint8_t mask = (1 << (8 - bit_offset)) - 1; if (byte_index < 16) { address->as_u8[byte_index] &= mask; for (int i = byte_index + 1; i < 16; i++) { address->as_u8[i] = 0; } } } int npt66_binding_add_del (u32 sw_if_index, ip6_address_t *internal, int internal_plen, ip6_address_t *external, int external_plen, bool is_add) { npt66_main_t *nm = &npt66_main; int rv = 0; /* Currently limited to a single binding per interface */ npt66_binding_t *b = npt66_interface_by_sw_if_index (sw_if_index); if (is_add) { bool configure_feature = false; /* Ensure prefix lengths are less than or equal to a /64 */ if (internal_plen > 64 || external_plen > 64) return VNET_API_ERROR_INVALID_VALUE; /* Create a binding entry (or update existing) */ if (!b) { pool_get_zero (nm->bindings, b); configure_feature = true; } b->internal = *internal; b->internal_plen = internal_plen; b->external = *external; b->external_plen = external_plen; b->sw_if_index = sw_if_index; ipv6_prefix_zero (&b->internal, internal_plen); ipv6_prefix_zero (&b->external, external_plen); vec_validate_init_empty (nm->interface_by_sw_if_index, sw_if_index, ~0); nm->interface_by_sw_if_index[sw_if_index] = b - nm->bindings; uword delta = 0; delta = ip_csum_add_even (delta, b->external.as_u64[0]); delta = ip_csum_add_even (delta, b->external.as_u64[1]); delta = ip_csum_sub_even (delta, b->internal.as_u64[0]); delta = ip_csum_sub_even (delta, b->internal.as_u64[1]); delta = ip_csum_fold (delta); b->delta = delta; if (configure_feature) rv = npt66_feature_enable_disable (sw_if_index, is_add); } else { /* Delete a binding entry */ npt66_binding_t *b = npt66_interface_by_sw_if_index (sw_if_index); if (!b) return VNET_API_ERROR_NO_SUCH_ENTRY; nm->interface_by_sw_if_index[sw_if_index] = ~0; pool_put (nm->bindings, b); rv = npt66_feature_enable_disable (sw_if_index, is_add); } return rv; } /* * Do a lookup in the interface vector (interface_by_sw_if_index) * and return pool entry. */ npt66_binding_t * npt66_interface_by_sw_if_index (u32 sw_if_index) { npt66_main_t *nm = &npt66_main; if (!nm->interface_by_sw_if_index || sw_if_index > (vec_len (nm->interface_by_sw_if_index) - 1)) return 0; u32 index = nm->interface_by_sw_if_index[sw_if_index]; if (index == ~0) return 0; if (pool_is_free_index (nm->bindings, index)) return 0; return pool_elt_at_index (nm->bindings, index); }