[dpdk-dev] [PATCH v6 6/6] doc/ipsec: update ipsec programmer's guide

[Vladimir Medvedkin <vladimir.medvedkin@intel.com>]

Add section about ipsec SAD
Update release notes

Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
---
 doc/guides/prog_guide/ipsec_lib.rst    | 152 +++++++++++++++++++++++++++++++++
 doc/guides/rel_notes/release_19_11.rst |   3 +
 2 files changed, 155 insertions(+)

diff --git a/doc/guides/prog_guide/ipsec_lib.rst b/doc/guides/prog_guide/ipsec_lib.rst
index 63b75b6..4487e4c 100644
--- a/doc/guides/prog_guide/ipsec_lib.rst
+++ b/doc/guides/prog_guide/ipsec_lib.rst
@@ -143,6 +143,158 @@ In that mode the library functions perform
 To accommodate future custom implementations function pointers
 model is used for both *crypto_prepare* and *process* implementations.
 
+SA database API
+----------------
+
+SA database(SAD) is a table with <key, value> pairs.
+
+Value is an opaque user provided pointer to the user defined SA data structure.
+
+According to RFC4301 each SA can be uniquely identified by a key
+which is either:
+
+  - security parameter index(SPI)
+  - or SPI and destination IP(DIP)
+  - or SPI, DIP and source IP(SIP)
+
+In case of multiple matches, longest matching key will be returned.
+
+Create/destroy
+~~~~~~~~~~~~~~
+
+librte_ipsec SAD implementation provides ability to create/destroy SAD tables.
+
+To create SAD table user has to specify how many entries of each key type is
+required and IP protocol type (IPv4/IPv6).
+As an example:
+
+
+.. code-block:: c
+
+    struct rte_ipsec_sad *sad;
+    struct rte_ipsec_sad_conf conf;
+
+    conf.socket_id = -1;
+    conf.max_sa[RTE_IPSEC_SAD_SPI_ONLY] = some_nb_rules_spi_only;
+    conf.max_sa[RTE_IPSEC_SAD_SPI_DIP] = some_nb_rules_spi_dip;
+    conf.max_sa[RTE_IPSEC_SAD_SPI_DIP_SIP] = some_nb_rules_spi_dip_sip;
+    conf.flags = RTE_IPSEC_SAD_FLAG_RW_CONCURRENCY;
+
+    sad = rte_ipsec_sad_create("test", &conf);
+
+.. note::
+
+    for more information please refer to ipsec library API reference
+
+Add/delete rules
+~~~~~~~~~~~~~~~~
+
+Library also provides methods to add or delete key/value pairs from the SAD.
+To add user has to specify key, key type and a value which is an opaque pointer to SA.
+The key type reflects a set of tuple fields that will be used for lookup of the SA.
+As mentioned above there are 3 types of a key and the representation of a key type is:
+
+.. code-block:: c
+
+        RTE_IPSEC_SAD_SPI_ONLY,
+        RTE_IPSEC_SAD_SPI_DIP,
+        RTE_IPSEC_SAD_SPI_DIP_SIP,
+
+As an example, to add new entry into the SAD for IPv4 addresses:
+
+.. code-block:: c
+
+    struct rte_ipsec_sa *sa;
+    union rte_ipsec_sad_key key;
+
+    key.v4.spi = rte_cpu_to_be_32(spi_val);
+    if (key_type >= RTE_IPSEC_SAD_SPI_DIP) /* DIP is optional*/
+        key.v4.dip = rte_cpu_to_be_32(dip_val);
+    if (key_type == RTE_IPSEC_SAD_SPI_DIP_SIP) /* SIP is optional*/
+        key.v4.sip = rte_cpu_to_be_32(sip_val);
+
+    rte_ipsec_sad_add(sad, &key, key_type, sa);
+
+.. note::
+
+    By performance reason it is better to keep spi/dip/sip in net byte order
+    to eliminate byteswap on lookup
+
+To delete user has to specify key and key type.
+
+Delete code would look like:
+
+.. code-block:: c
+
+    union rte_ipsec_sad_key key;
+
+    key.v4.spi = rte_cpu_to_be_32(necessary_spi);
+    if (key_type >= RTE_IPSEC_SAD_SPI_DIP) /* DIP is optional*/
+        key.v4.dip = rte_cpu_to_be_32(necessary_dip);
+    if (key_type == RTE_IPSEC_SAD_SPI_DIP_SIP) /* SIP is optional*/
+        key.v4.sip = rte_cpu_to_be_32(necessary_sip);
+
+    rte_ipsec_sad_del(sad, &key, key_type);
+
+
+Lookup
+~~~~~~
+Library provides lookup by the given {SPI,DIP,SIP} tuple of
+inbound ipsec packet as a key.
+
+The search key is represented by:
+
+.. code-block:: c
+
+    union rte_ipsec_sad_key {
+        struct rte_ipsec_sadv4_key  v4;
+        struct rte_ipsec_sadv6_key  v6;
+    };
+
+where v4 is a tuple for IPv4:
+
+.. code-block:: c
+
+    struct rte_ipsec_sadv4_key {
+        uint32_t spi;
+        uint32_t dip;
+        uint32_t sip;
+    };
+
+and v6 is a tuple for IPv6:
+
+.. code-block:: c
+
+    struct rte_ipsec_sadv6_key {
+        uint32_t spi;
+        uint8_t dip[16];
+        uint8_t sip[16];
+    };
+
+As an example, lookup related code could look like that:
+
+.. code-block:: c
+
+    int i;
+    union rte_ipsec_sad_key keys[BURST_SZ];
+    const union rte_ipsec_sad_key *keys_p[BURST_SZ];
+    void *vals[BURST_SZ];
+
+    for (i = 0; i < BURST_SZ_MAX; i++) {
+        keys[i].v4.spi = esp_hdr[i]->spi;
+        keys[i].v4.dip = ipv4_hdr[i]->dst_addr;
+        keys[i].v4.sip = ipv4_hdr[i]->src_addr;
+        keys_p[i] = &keys[i];
+    }
+    rte_ipsec_sad_lookup(sad, keys_p, vals, BURST_SZ);
+
+    for (i = 0; i < BURST_SZ_MAX; i++) {
+        if (vals[i] == NULL)
+            printf("SA not found for key index %d\n", i);
+        else
+            printf("SA pointer is %p\n", vals[i]);
+    }
+
 
 Supported features
 ------------------
diff --git a/doc/guides/rel_notes/release_19_11.rst b/doc/guides/rel_notes/release_19_11.rst
index 85953b9..581f311 100644
--- a/doc/guides/rel_notes/release_19_11.rst
+++ b/doc/guides/rel_notes/release_19_11.rst
@@ -115,6 +115,9 @@ New Features
   Added eBPF JIT support for arm64 architecture to improve the eBPF program
   performance.
 
+* **Updated the IPSec library.**
+
+ Added SA Database API to ``librte_ipsec``
 
 Removed Items
 -------------
-- 
2.7.4