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-rw-r--r--src/plugins/cnat/cnat_snat.c252
1 files changed, 252 insertions, 0 deletions
diff --git a/src/plugins/cnat/cnat_snat.c b/src/plugins/cnat/cnat_snat.c
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+/*
+ * 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 <vnet/ip/ip.h>
+#include <cnat/cnat_snat.h>
+
+static void
+cnat_compute_prefix_lengths_in_search_order (cnat_snat_pfx_table_t *
+ table, ip_address_family_t af)
+{
+ int i;
+ vec_reset_length (table->meta[af].prefix_lengths_in_search_order);
+ /* Note: bitmap reversed so this is in fact a longest prefix match */
+ /* *INDENT-OFF* */
+ clib_bitmap_foreach (i, table->meta[af].non_empty_dst_address_length_bitmap,
+ ({
+ int dst_address_length = 128 - i;
+ vec_add1 (table->meta[af].prefix_lengths_in_search_order, dst_address_length);
+ }));
+ /* *INDENT-ON* */
+}
+
+int
+cnat_add_snat_prefix (ip_prefix_t * pfx)
+{
+ /* All packets destined to this prefix won't be source-NAT-ed */
+ cnat_snat_pfx_table_t *table = &cnat_main.snat_pfx_table;
+ clib_bihash_kv_24_8_t kv;
+ ip6_address_t *mask;
+ u64 af = ip_prefix_version (pfx);;
+
+ mask = &table->ip_masks[pfx->len];
+ if (AF_IP4 == af)
+ {
+ kv.key[0] = (u64) ip_prefix_v4 (pfx).as_u32 & mask->as_u64[0];
+ kv.key[1] = 0;
+ }
+ else
+ {
+ kv.key[0] = ip_prefix_v6 (pfx).as_u64[0] & mask->as_u64[0];
+ kv.key[1] = ip_prefix_v6 (pfx).as_u64[1] & mask->as_u64[1];
+ }
+ kv.key[2] = ((u64) af << 32) | pfx->len;
+ clib_bihash_add_del_24_8 (&table->ip_hash, &kv, 1 /* is_add */ );
+
+ table->meta[af].dst_address_length_refcounts[pfx->len]++;
+ table->meta[af].non_empty_dst_address_length_bitmap =
+ clib_bitmap_set (table->meta[af].non_empty_dst_address_length_bitmap,
+ 128 - pfx->len, 1);
+ cnat_compute_prefix_lengths_in_search_order (table, af);
+ return 0;
+}
+
+int
+cnat_del_snat_prefix (ip_prefix_t * pfx)
+{
+ cnat_snat_pfx_table_t *table = &cnat_main.snat_pfx_table;
+ clib_bihash_kv_24_8_t kv, val;
+ ip6_address_t *mask;
+ u64 af = ip_prefix_version (pfx);;
+
+ mask = &table->ip_masks[pfx->len];
+ if (AF_IP4 == af)
+ {
+ kv.key[0] = (u64) ip_prefix_v4 (pfx).as_u32 & mask->as_u64[0];
+ kv.key[1] = 0;
+ }
+ else
+ {
+ kv.key[0] = ip_prefix_v6 (pfx).as_u64[0] & mask->as_u64[0];
+ kv.key[1] = ip_prefix_v6 (pfx).as_u64[1] & mask->as_u64[1];
+ }
+ kv.key[2] = ((u64) af << 32) | pfx->len;
+
+ if (clib_bihash_search_24_8 (&table->ip_hash, &kv, &val))
+ {
+ return 1;
+ }
+ clib_bihash_add_del_24_8 (&table->ip_hash, &kv, 0 /* is_add */ );
+ /* refcount accounting */
+ ASSERT (table->meta[af].dst_address_length_refcounts[pfx->len] > 0);
+ if (--table->meta[af].dst_address_length_refcounts[pfx->len] == 0)
+ {
+ table->meta[af].non_empty_dst_address_length_bitmap =
+ clib_bitmap_set (table->meta[af].non_empty_dst_address_length_bitmap,
+ 128 - pfx->len, 0);
+ cnat_compute_prefix_lengths_in_search_order (table, af);
+ }
+ return 0;
+}
+
+u8 *
+format_cnat_snat_prefix (u8 * s, va_list * args)
+{
+ clib_bihash_kv_24_8_t *kv = va_arg (*args, clib_bihash_kv_24_8_t *);
+ CLIB_UNUSED (int verbose) = va_arg (*args, int);
+ u32 af = kv->key[2] >> 32;
+ u32 len = kv->key[2] & 0xffffffff;
+ if (AF_IP4 == af)
+ s = format (s, "%U/%d", format_ip4_address, &kv->key[0], len);
+ else
+ s = format (s, "%U/%d", format_ip6_address, &kv->key[0], len);
+ return (s);
+}
+
+static clib_error_t *
+cnat_set_snat (vlib_main_t * vm,
+ unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+ ip_address_t addr;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "%U", unformat_ip_address, &addr))
+ {
+ if (ip_addr_version (&addr) == AF_IP4)
+ clib_memcpy (&cnat_main.snat_ip4, &ip_addr_v4 (&addr),
+ sizeof (ip4_address_t));
+ else
+ clib_memcpy (&cnat_main.snat_ip6, &ip_addr_v6 (&addr),
+ sizeof (ip6_address_t));
+ }
+ else
+ return (clib_error_return (0, "unknown input '%U'",
+ format_unformat_error, input));
+ }
+
+ return (NULL);
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (cnat_set_snat_command, static) =
+{
+ .path = "cnat snat with",
+ .short_help = "cnat snat with [ip]",
+ .function = cnat_set_snat,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+cnat_snat_exclude (vlib_main_t * vm,
+ unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+ ip_prefix_t pfx;
+ u8 is_add = 1;
+ int rv;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "%U", unformat_ip_prefix, &pfx))
+ ;
+ else if (unformat (input, "del"))
+ is_add = 0;
+ else
+ return (clib_error_return (0, "unknown input '%U'",
+ format_unformat_error, input));
+ }
+
+ if (is_add)
+ rv = cnat_add_snat_prefix (&pfx);
+ else
+ rv = cnat_del_snat_prefix (&pfx);
+
+ if (rv)
+ {
+ return (clib_error_return (0, "error %d", rv, input));
+ }
+
+ return (NULL);
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (cnat_snat_exclude_command, static) =
+{
+ .path = "cnat snat exclude",
+ .short_help = "cnat snat exclude [ip]",
+ .function = cnat_snat_exclude,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+cnat_show_snat (vlib_main_t * vm,
+ unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+ cnat_snat_pfx_table_t *table = &cnat_main.snat_pfx_table;
+ vlib_cli_output (vm, "Source NAT\nip4: %U\nip6: %U\n",
+ format_ip4_address, &cnat_main.snat_ip4,
+ format_ip6_address, &cnat_main.snat_ip6);
+ vlib_cli_output (vm, "Prefixes:\n%U\n",
+ format_bihash_24_8, &table->ip_hash, 1);
+ return (NULL);
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (cnat_show_snat_command, static) =
+{
+ .path = "show cnat snat",
+ .short_help = "show cnat snat",
+ .function = cnat_show_snat,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+cnat_snat_init (vlib_main_t * vm)
+{
+ cnat_snat_pfx_table_t *table = &cnat_main.snat_pfx_table;
+ cnat_main_t *cm = &cnat_main;
+ int i;
+ for (i = 0; i < ARRAY_LEN (table->ip_masks); i++)
+ {
+ u32 j, i0, i1;
+
+ i0 = i / 32;
+ i1 = i % 32;
+
+ for (j = 0; j < i0; j++)
+ table->ip_masks[i].as_u32[j] = ~0;
+
+ if (i1)
+ table->ip_masks[i].as_u32[i0] =
+ clib_host_to_net_u32 (pow2_mask (i1) << (32 - i1));
+ }
+ clib_bihash_init_24_8 (&table->ip_hash, "snat prefixes",
+ cm->snat_hash_buckets, cm->snat_hash_memory);
+ clib_bihash_set_kvp_format_fn_24_8 (&table->ip_hash,
+ format_cnat_snat_prefix);
+
+ return (NULL);
+}
+
+VLIB_INIT_FUNCTION (cnat_snat_init);
+
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */