三層交換機之VLAN_XLATE

博通交換芯片中，QinQ域功能實現主要依賴於VLAN_XLATE和VCAP(VFP)資源實現。其中，VLAN_XLATE實現常規QinQ域；VCAP實現靈活QinQ域，因為靈活QinQ域需要匹配除VLAN和MAC之外的其他字段，比如EtherType、IpProtocol、UDP Src/Dst Port等，這種方式又稱為基於流（Based on Flow）。

VLAN_XLATE和EGR_VLAN_XLATE表均包含多個表項資源，使用Hash算法查找。

VLAN_XLATE

VLAN_XLATE表查找有兩種相互獨立的方式，首先使用PORT_TAB.VT_KEY_TYPE作為Key值進行Hash查找，查找失敗的情況下，繼續使用PORT_TAB.VT_KEY_TYPE2作為Key值進行Hash查找。

 

 

/* Key types for vlan translation lookup. */
typedef enum bcm_vlan_translate_key_e {
    bcmVlanTranslateKeyInvalid,         /* Invalid Key Type. */
    bcmVlanTranslateKeyDouble,          /* Use O-VID[11:0] and I-VID[11:0]. */
    bcmVlanTranslateKeyOuter,           /* Use O-VID[11:0] */
    bcmVlanTranslateKeyInner,           /* Use I-VID[11:0] */
    bcmVlanTranslateKeyOuterTag,        /* Use O-TAG[15:0] */
    bcmVlanTranslateKeyInnerTag,        /* Use I-TAG[15:0] */
    bcmVlanTranslateKeyOuterPri,        /* Use (VLAN-PRI, VLAN-CFI => O-TAG[15:12]) */
    bcmVlanTranslateKeyPortDouble,      /* Use Port, O-VID[11:0] and I-VID[11:0]. */
    bcmVlanTranslateKeyPortOuter,       /* Use Port, O-VID[11:0] */
    bcmVlanTranslateKeyPortInner,       /* Use Port, I-VID[11:0] */
    bcmVlanTranslateKeyPortOuterTag,    /* Use Port, O-TAG[15:0] */
    bcmVlanTranslateKeyPortInnerTag,    /* Use Port, I-TAG[15:0] */
    bcmVlanTranslateKeyPortOuterPri     /* Use Port, (VLAN-PRI, VLAN-CFI =>O-TAG[15:12]) */
} bcm_vlan_translate_key_t;

EGR_VLAN_XLATE

首先進行DT查找，然后進行OVID查找。

VLAN RANGE CHECKING

允許將CVID(Customer VLAN ID)或者IVID(Inner VLAN ID)范圍段映射到相同的PVID/SVID/OVID，這樣可以使用一條VLAN_XLATE表項和VLAN_PROFILE表項實現，從而節省VLAN_XLATE資源：

1） 最多支持128個VLAN RANGE profiles

2） 每個VLAN RANGE profile最多支持8個VLAN RANGEs

3） 同一個VLAN RANGE profile內的8個VLAN RANGEs不能重疊

4） CVID和PVID/SVID不能重疊

過程如下：

1） 入端口報文CVID進入VLAN range checking邏輯，通過(MODID, port)索引VLAN_RANGE_IDX表，返回指向IGR_VLAN_RANGE_TBL的索引號；

2） IGR_VLAN_RANGE_TBL的每個表項包含6個VLAN對（MIN,MAX）支持6個VLAN范圍段；如果CVID與任意VLAN對匹配，則命中，該報文的CVID被替換為VLAN_MIN值；如果未命中，則CVID用來進行VLAN_XLATE查找；

BCM SDK API

Ingress

/* Add an entry to the VLAN Translation table. */
extern int bcm_vlan_translate_add(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t new_vid, 
int prio);

 將指定端口入端口old_vid的報文轉換為new_vid的報文。

對於StrataXGS III系列交換芯片，支持優先級替換，prio為-1表示轉換后不更改報文優先級，prio為0~7表示轉換后的報文優先級。

對於支持VLAN action API的交換芯片，prio表示內部優先級，不支持-1。

/* Add an entry to the VLAN Translation table. */
extern int bcm_vlan_translate_get(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t *new_vid, 
int *prio);

 

/* Delete an entry or entries from the VLAN Translation table. */
extern int bcm_vlan_translate_delete(
int unit, 
int port, 
bcm_vlan_t old_vid);

 刪除old_vid相關的所有VLAN_XLATE表項

/* Remove all entries from the VLAN Translation table. */
extern int bcm_vlan_translate_delete_all(
int unit);

 

/* Add an entry to the VLAN Translation table and assign VLAN actions. */
extern int bcm_vlan_translate_action_add(
int unit, 
bcm_gport_t port, 
bcm_vlan_translate_key_t key_type, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan, 
bcm_vlan_action_set_t *action);

 key_type必須為bcmVlanPortTranslateKeyFirst或者bcmVlanPortTranslateKeySecond之一，它們由bcm_vlan_control_port_set配置，可以通過bcm_vlan_control_port_get獲取。

使用bcm_vlan_translate_action_add創建VLAN_XLATE表項轉換的報文必須是tagged。

/* Get an entry to the VLAN Translation table and assign VLAN actions. */
extern int bcm_vlan_translate_action_get(
int unit, 
bcm_gport_t port, 
bcm_vlan_translate_key_t key_type, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan, 
bcm_vlan_action_set_t *action);

 

/* Delete an entry from the VLAN Translation table. */
extern int bcm_vlan_translate_action_delete(
int unit, 
bcm_gport_t port, 
bcm_vlan_translate_key_t key_type, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan);

獲取指定端口、key_type和VLAN的VLAN_XLATE動作。

Egress

/* Add an entry to the egress VLAN Translation table. */
extern int bcm_vlan_translate_egress_add(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t new_vid, 
int prio);

 

/* Get an entry to the egress VLAN Translation table. */
extern int bcm_vlan_translate_egress_get(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t *new_vid, 
int *prio);

 

/* Remove an entry or entries from the VLAN egress Translation table. */
extern int bcm_vlan_translate_egress_delete(
int unit, 
int port, 
bcm_vlan_t old_vid);

 

/* Remove all entries from the egress VLAN Translation table. */
extern int bcm_vlan_translate_egress_delete_all(
int unit);

 

/* 
* Add an entry to the egress VLAN Translation table and assign VLAN
* actions.
*/
extern int bcm_vlan_translate_egress_action_add(
int unit, 
int port_class, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan, 
bcm_vlan_action_set_t *action);

 

/* 
* Get an entry to the egress VLAN Translation table and assign VLAN
* actions.
*/
extern int bcm_vlan_translate_egress_action_get(
int unit, 
int port_class, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan, 
bcm_vlan_action_set_t *action);

 

/* Delete an entry from the egress VLAN Translation table. */
extern int bcm_vlan_translate_egress_action_delete(
int unit, 
int port_class, 
bcm_vlan_t outer_vlan, 
bcm_vlan_t inner_vlan);

 

 

Dtag & Vlan Range

/* Add an entry to the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_add(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t new_vid, 
int prio);

對入端口VLAN為old_vid的single inner-tagged的報文添加new_vid的外層VLAN。 

/* Get an entry to the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_get(
int unit, 
int port, 
bcm_vlan_t old_vid, 
bcm_vlan_t *new_vid, 
int *prio);

 

/* Remove an entry from the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_delete(
int unit, 
int port, 
bcm_vlan_t old_vid);

 

/* Remove all entries from the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_delete_all(
int unit);

 

/* Add a VLAN range to the VLAN Translation table. */
extern int bcm_vlan_translate_range_add(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high, 
bcm_vlan_t new_vid, 
int int_prio);

將入端口VLAN在old_vid_low~old_vid_high范圍以內的報文，轉換為new_vid的報文。

/* Get a VLAN range to the VLAN Translation table. */
extern int bcm_vlan_translate_range_get(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high, 
bcm_vlan_t *new_vid, 
int *int_prio);

 

/* Delete a VLAN range from the VLAN Translation table. */
extern int bcm_vlan_translate_range_delete(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high);

 

/* Remove all VLAN ranges from the VLAN Translation table. */
extern int bcm_vlan_translate_range_delete_all(
int unit);

 

/* Add VLAN range to the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_range_add(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high, 
bcm_vlan_t new_vid, 
int int_prio);

對於入端口VLAN在old_vid_low~old_vid_high范圍內的single inner-tagged的報文，添加new_vid的外層VLAN。 

/* Get VLAN range to the VLAN Translation table for double-tagging. */
extern int bcm_vlan_dtag_range_get(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high, 
bcm_vlan_t *new_vid, 
int *prio);

 

/* 
* Remove a VLAN range from the VLAN Translation table for
* double-tagging.
*/
extern int bcm_vlan_dtag_range_delete(
int unit, 
int port, 
bcm_vlan_t old_vid_low, 
bcm_vlan_t old_vid_high);

 

/* 
* Remove all VLAN ranges from the VLAN Translation table for
* double-tagging.
*/
extern int bcm_vlan_dtag_range_delete_all(
int unit);

 

 

/* bcm_vlan_translate_action_range_add */
extern int bcm_vlan_translate_action_range_add(
int unit, 
bcm_gport_t port, 
bcm_vlan_t outer_vlan_low, 
bcm_vlan_t outer_vlan_high, 
bcm_vlan_t inner_vlan_low, 
bcm_vlan_t inner_vlan_high, 
bcm_vlan_action_set_t *action);

 如果要轉換double-tagged或者single outer-tagged報文，那么outer_vlan_low/high用來指定入端口報文外層VLAN的范圍，inner_vlan_low/high必須指定為BCM_VLAN_INVALID。同時，入端口必須通過bcm_vlan_control_port_set配置為bcmVlanPortTranslateKeyOuter。

如果要轉換single inner-tagged報文，那么inner_vlan_low/high指定VLAN范圍，outer_vlan_low/high必須指定為BCM_VLAN_INVALID。同時，入端口必須通過bcm_vlan_control_port_set配置為bcmVlanPortTranslateKeyInner。

對於untagged報文，該VLAN_XLATE表項無效。

/* bcm_vlan_translate_action_range_get */
extern int bcm_vlan_translate_action_range_get(
int unit, 
bcm_gport_t port, 
bcm_vlan_t outer_vlan_low, 
bcm_vlan_t outer_vlan_high, 
bcm_vlan_t inner_vlan_low, 
bcm_vlan_t inner_vlan_high, 
bcm_vlan_action_set_t *action);

 

/* bcm_vlan_translate_action_range_delete */
extern int bcm_vlan_translate_action_range_delete(
int unit, 
bcm_gport_t port, 
bcm_vlan_t outer_vlan_low, 
bcm_vlan_t outer_vlan_high, 
bcm_vlan_t inner_vlan_low, 
bcm_vlan_t inner_vlan_high);

 

/* bcm_vlan_translate_action_range_delete_all */
extern int bcm_vlan_translate_action_range_delete_all(
int unit);