zebra: Add support for SRv6 SID formats

Add functionalities to manage SRv6 SID formats (register / unregister /
lookup) and create two SID formats upon SRv6 Manager initialization:
`uncompressed-f4024` and `usid-f3216`.

In future commits, we will add the CLI to allow the user to choose
between the two formats.

Signed-off-by: Carmine Scarpitta <cscarpit@cisco.com>

1 files changed, 125 insertions, 7 deletions

diff --git a/zebra/zebra_srv6.c b/zebra/zebra_srv6.c
index bb872ef91c..dffc6ca091 100644
--- a/zebra/zebra_srv6.c
+++ b/zebra/zebra_srv6.c
@@ -90,6 +90,98 @@ static int zebra_srv6_cleanup(struct zserv *client)
 	return 0;
 }
 
+/* --- Zebra SRv6 SID format management functions --------------------------- */
+
+void zebra_srv6_sid_format_register(struct zebra_srv6_sid_format *format)
+{
+	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
+
+	/* Ensure that the format is registered only once */
+	assert(!zebra_srv6_sid_format_lookup(format->name));
+
+	listnode_add(srv6->sid_formats, format);
+}
+
+void zebra_srv6_sid_format_unregister(struct zebra_srv6_sid_format *format)
+{
+	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
+
+	listnode_delete(srv6->sid_formats, format);
+}
+
+struct zebra_srv6_sid_format *zebra_srv6_sid_format_lookup(const char *name)
+{
+	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
+	struct zebra_srv6_sid_format *format;
+	struct listnode *node;
+
+	for (ALL_LIST_ELEMENTS_RO(srv6->sid_formats, node, format))
+		if (!strncmp(name, format->name, sizeof(format->name)))
+			return format;
+
+	return NULL;
+}
+
+/*
+ * Helper function to create the SRv6 compressed format `usid-f3216`.
+ */
+static struct zebra_srv6_sid_format *create_srv6_sid_format_usid_f3216(void)
+{
+	struct zebra_srv6_sid_format *format = NULL;
+
+	format = zebra_srv6_sid_format_alloc(
+		ZEBRA_SRV6_SID_FORMAT_USID_F3216_NAME);
+
+	format->type = SRV6_SID_FORMAT_TYPE_USID;
+
+	/* Define block/node/function length */
+	format->block_len = ZEBRA_SRV6_SID_FORMAT_USID_F3216_BLOCK_LEN;
+	format->node_len = ZEBRA_SRV6_SID_FORMAT_USID_F3216_NODE_LEN;
+	format->function_len = ZEBRA_SRV6_SID_FORMAT_USID_F3216_FUNCTION_LEN;
+	format->argument_len = ZEBRA_SRV6_SID_FORMAT_USID_F3216_ARGUMENT_LEN;
+
+	/* Define the ranges from which the SID function can be allocated */
+	format->config.usid.lib_start =
+		ZEBRA_SRV6_SID_FORMAT_USID_F3216_LIB_START;
+	format->config.usid.elib_start =
+		ZEBRA_SRV6_SID_FORMAT_USID_F3216_ELIB_START;
+	format->config.usid.elib_end = ZEBRA_SRV6_SID_FORMAT_USID_F3216_ELIB_END;
+	format->config.usid.wlib_start =
+		ZEBRA_SRV6_SID_FORMAT_USID_F3216_WLIB_START;
+	format->config.usid.wlib_end = ZEBRA_SRV6_SID_FORMAT_USID_F3216_WLIB_END;
+	format->config.usid.ewlib_start =
+		ZEBRA_SRV6_SID_FORMAT_USID_F3216_EWLIB_START;
+
+	return format;
+}
+
+/*
+ * Helper function to create the SRv6 uncompressed format.
+ */
+static struct zebra_srv6_sid_format *create_srv6_sid_format_uncompressed(void)
+{
+	struct zebra_srv6_sid_format *format = NULL;
+
+	format = zebra_srv6_sid_format_alloc(
+		ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_NAME);
+
+	format->type = ZEBRA_SRV6_SID_FORMAT_TYPE_UNCOMPRESSED;
+
+	/* Define block/node/function length */
+	format->block_len = ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_BLOCK_LEN;
+	format->node_len = ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_NODE_LEN;
+	format->function_len =
+		ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_FUNCTION_LEN;
+	format->argument_len =
+		ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_ARGUMENT_LEN;
+
+	/* Define the ranges from which the SID function can be allocated */
+	format->config.uncompressed.explicit_start =
+		ZEBRA_SRV6_SID_FORMAT_UNCOMPRESSED_F4024_EXPLICIT_RANGE_START;
+
+	return format;
+}
+
 void zebra_srv6_locator_add(struct srv6_locator *locator)
 {
 	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
@@ -222,10 +314,24 @@ struct zebra_srv6 srv6;
 struct zebra_srv6 *zebra_srv6_get_default(void)
 {
 	static bool first_execution = true;
+	struct zebra_srv6_sid_format *format_usidf3216;
+	struct zebra_srv6_sid_format *format_uncompressed;
 
 	if (first_execution) {
 		first_execution = false;
 		srv6.locators = list_new();
+
+		/* Initialize list of SID formats */
+		srv6.sid_formats = list_new();
+		srv6.sid_formats->del = delete_zebra_srv6_sid_format;
+
+		/* Create SID format `usid-f3216` */
+		format_usidf3216 = create_srv6_sid_format_usid_f3216();
+		zebra_srv6_sid_format_register(format_usidf3216);
+
+		/* Create SID format `uncompressed` */
+		format_uncompressed = create_srv6_sid_format_uncompressed();
+		zebra_srv6_sid_format_register(format_uncompressed);
 	}
 	return &srv6;
 }
@@ -430,18 +536,30 @@ void zebra_srv6_encap_src_addr_unset(void)
 void zebra_srv6_terminate(void)
 {
 	struct srv6_locator *locator;
+	struct zebra_srv6_sid_format *format;
 
-	if (!srv6.locators)
-		return;
+	if (srv6.locators) {
+		while (listcount(srv6.locators)) {
+			locator = listnode_head(srv6.locators);
 
-	while (listcount(srv6.locators)) {
-		locator = listnode_head(srv6.locators);
+			listnode_delete(srv6.locators, locator);
+			srv6_locator_free(locator);
+		}
 
-		listnode_delete(srv6.locators, locator);
-		srv6_locator_free(locator);
+		list_delete(&srv6.locators);
 	}
 
-	list_delete(&srv6.locators);
+	/* Free SRv6 SID formats */
+	if (srv6.sid_formats) {
+		while (listcount(srv6.sid_formats)) {
+			format = listnode_head(srv6.sid_formats);
+
+			zebra_srv6_sid_format_unregister(format);
+			zebra_srv6_sid_format_free(format);
+		}
+
+		list_delete(&srv6.sid_formats);
+	}
 }
 
 void zebra_srv6_init(void)