These functions handle the encapsulation and transmission of 802.11 frames within the software 802.11 stack.
The ieee80211_encap function encapsulates an outbound data frame contained within the mbuf chain m from the interface ifp. The argument *pni is a reference to the destination node.
If the function is successful, the mbuf chain is updated with the 802.11 frame header prepended, and a pointer to the head of the chain is returned. If an error occurs, NULL will be returned, and *pni is also set to NULL. The caller is responsible for freeing the node reference if *pni is non- NULL on return. The convention is that ic_bss is not reference counted; the caller is responsible for maintaining this reference count.
The ieee80211_add_rates utility function is used to add the rate set element *rs to the frame frm. A pointer to the location in the buffer after the addition of the rate set is returned. It is typically used when constructing management frames from within the software 802.11 stack.
The ieee80211_add_xrates utility function is used to add the extended rate set element *rs to the frame frm. A pointer to the location in the buffer after the addition of the rate set is returned. It is typically used when constructing management frames from within the software 802.11 stack in 802.11g mode.
The ieee80211_send_mgmt function transmits a management frame on the interface ic to the destination node ni of type type.
The argument arg specifies either a sequence number for authentication operations, a status code for [re]association operations, or a reason for deauthentication and deassociation operations.
Nodes other than ic_bss have their reference count incremented to reflect their use for an indeterminate amount of time. This reference is freed when the function returns.
The function returns 0 if successful; if temporary buffer space is not available, the function returns ENOMEM.