| liblldp_clif(3) | Linux | liblldp_clif(3) |
clif_vsi,clif_vsievt,clif_vsiwait - Manipulate VDP IEEE 802.1 Ratified Standard Associations
#include "include/clif.h"
int clif_vsi(struct clif *connp, char *ifname, unsigned int tlvid, char *cmd, char *reply, size_t *reply_len);
int clif_vsievt(struct clif *connp, char *reply, size_t *reply_len, int wait);
int clif_vsiwait(struct clif *connp, char *ifname, unsigned int tlvid, char *cmd, char *reply, size_t *reply_len, int wait);
The Virtual station interface Discovery Protocol is a protocol to manage the association and deassociation of virtual machine network interfaces (VSIs) between the station and an adjacent switch. VDP is typically used with the local switch in VEPA mode and the adjacent switch port in reflective relay (also called haripin) mode. This allows all traffic to be sent to the switch for processing. Reflective relay mode is negotiated via EVB TLVs (see lldptool-evb).
This man pages describes the IEEE 802.1 Qbg ratified standard dated from July 5th, 2012. This differs from the draft 0.2 which is implemented as well, see lldptool-vdp(8). For clarification in this man page the version complying to the ratified standard is called VDP22 and the version complying to the draft 0.2 is called VDP.
Each VDP22 TLVs contains a command mode, manager identifier, type identifier, type identifier version, VSI instance identifier, migiration hints and filter information. The fields are explained next:
This function sends a VSI command to lldpad(8). Parameter connp is a pointer to the connection information. This information is obtained by calling clif_open and clif_attach. Parameter ifname is the interface name lldpad (8) uses to send the VSI data. Paramenter tlvid is the number of the VSI request. Valid numbers are 1 (for Preassociation), 2 (for Preassociation with resource reservation) and 3 (for association), 4 (for Deassociation). Parameter cmd points to a character string containing the VSI command. The layout of the VSI command has been explained above. All VSI fields are concatenated together and separated to by commas (',') to form one large string. Parameter reply is a pointer to a character array to receive the reply from lldpad(8). Parameter reply_len holds the maximum number of characters available in the array pointed to by reply. On successful return of the call, reply_len contains the number of characters stored by lldpad(8) as the response of the command.
The functions returns zero on success and the reply and reply_len parameters are set. Reply_len contains the number of bytes in the memory area pointed to by reply. Reply contains the same information and format as the cmd parameter with several exceptions:
The function returns zero when the command was accepted by lldpad(8). Otherwise it returns a positive number on why the command was not accepted.
After a successful return of clif_vsi, lldpad(8) has sent the command to the switch and waits for a response from the switch. The switch can still deny the request. Function clif_vsievt waits for parameter wait seconds for a reply from lldpad(8). Parameter reply_len specifies the maximum buffer size pointed to by parameter reply. If a response was received in wait seconds, the function returns zero and sets reply_len to the number of bytes received and reply contains the response. The format is the same as in clif_vsi.
Since the switch can disassociate an established VSI association any time, it is recommended to call clif_vsievt periodically to check for disassociate event messages from lldpad(8).
If the functions fails it returns
This function combines clif_vsi and clif_vsievt into one function call.
Code sample to create an VSI association on eth0:
char ok[MAX_CLIF_MSGBUF];
int rc;
size_t ok_len = sizeof(ok);
char *cmd ="assoc,blabla,12345,1,00000000-1111-2222-3333-aabbccddeeff"
",none,10-aa:bb:00:00:00:10,11-aa:bb:00:00:00:11";
struct clif *tool_conn = clif_open();
if (!tool_conn) {
fprintf(stderr, "%s can not open connection to LLDPAD0,
progname);
exit(5);
}
/* Attach to the vdp22 module */
if (clif_attach(tool_conn, "80c4")) {
fprintf(stderr, "%s can not attach to LLDPAD0, progname);
clif_close(tool_conn);
tool_conn = NULL;
exit(5);
}
rc = clif_vsiwait(tool_conn, "eth0", 1, cmd, ok, &ok_len, 5);
if (!rc) {
/* Parse the response in ok */
....
}
clif_detach(tool_conn));
clif_close(tool_conn);
lldptool-vdp(8), lldptool-evb(8),
lldptool-evb22(8), lldptool(8), lldpad(8)
IEEE 802.1Qbg (http://www.ieee802.org/1/pages/802.1bg.html)
Thomas Richter
| February 2014 | open-lldp |