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struct nl_msg *build_msg(int ifindex, struct nl_addr *lladdr, int mtu)
{
struct nl_msg *msg;
struct nlattr *info, *vlan;
struct ifinfomsg ifi = {
.ifi_family = AF_INET,
.ifi_index = ifindex,
};
/* Allocate a default sized netlink message */
if (!(msg = nlmsg_alloc_simple(RTM_SETLINK, 0)))
return NULL;
/* Append the protocol specific header (struct ifinfomsg)*/
if (nlmsg_append(msg, &ifi, sizeof(ifi), NLMSG_ALIGNTO) < 0)
goto nla_put_failure
/* Append a 32 bit integer attribute to carry the MTU */
NLA_PUT_U32(msg, IFLA_MTU, mtu);
/* Append a unspecific attribute to carry the link layer address */
NLA_PUT_ADDR(msg, IFLA_ADDRESS, lladdr);
/* Append a container for nested attributes to carry link information */
if (!(info = nla_nest_start(msg, IFLA_LINKINFO)))
goto nla_put_failure;
/* Put a string attribute into the container */
NLA_PUT_STRING(msg, IFLA_INFO_KIND, "vlan");
/*
* Append another container inside the open container to carry
* vlan specific attributes
*/
if (!(vlan = nla_nest_start(msg, IFLA_INFO_DATA)))
goto nla_put_failure;
/* add vlan specific info attributes here... */
/* Finish nesting the vlan attributes and close the second container. */
nla_nest_end(msg, vlan);
/* Finish nesting the link info attribute and close the first container. */
nla_nest_end(msg, info);
return msg;
nla_put_failure:
nlmsg_free(msg);
return NULL;
}
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