dev_queue_xmit(9) [centos man page]

DEV_QUEUE_XMIT(9)					      Network device support						 DEV_QUEUE_XMIT(9)

NAME

       dev_queue_xmit - transmit a buffer

SYNOPSIS

       int dev_queue_xmit(struct sk_buff * skb);

ARGUMENTS

       skb
	   buffer to transmit

DESCRIPTION

       Queue a buffer for transmission to a network device. The caller must have set the device and priority and built the buffer before calling
       this function. The function can be called from an interrupt.

       A negative errno code is returned on a failure. A success does not guarantee the frame will be transmitted as it may be dropped due to
       congestion or traffic shaping.

       ----------------------------------------------------------------------------------- I notice this method can also return errors from the
       queue disciplines, including NET_XMIT_DROP, which is a positive value. So, errors can also be positive.

       Regardless of the return value, the skb is consumed, so it is currently difficult to retry a send to this method. (You can bump the ref
       count before sending to hold a reference for retry if you are careful.)

       When calling this method, interrupts MUST be enabled. This is because the BH enable code must have IRQs enabled so that it will not
       deadlock. --BLG

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							 DEV_QUEUE_XMIT(9)

STRUCT 
IEEE80211_TX_(9) 				      Rate control interface					   STRUCT IEEE80211_TX_(9)

NAME

       struct_ieee80211_tx_rate_control - rate control information for/from RC algo

SYNOPSIS

       struct ieee80211_tx_rate_control {
	 struct ieee80211_hw * hw;
	 struct ieee80211_supported_band * sband;
	 struct ieee80211_bss_conf * bss_conf;
	 struct sk_buff * skb;
	 struct ieee80211_tx_rate reported_rate;
	 bool rts;
	 bool short_preamble;
	 u8 max_rate_idx;
	 u32 rate_idx_mask;
	 u8 * rate_idx_mcs_mask;
	 bool bss;
       };

MEMBERS

       hw
	   The hardware the algorithm is invoked for.

       sband
	   The band this frame is being transmitted on.

       bss_conf
	   the current BSS configuration

       skb
	   the skb that will be transmitted, the control information in it needs to be filled in

       reported_rate
	   The rate control algorithm can fill this in to indicate which rate should be reported to userspace as the current rate and used for
	   rate calculations in the mesh network.

       rts
	   whether RTS will be used for this frame because it is longer than the RTS threshold

       short_preamble
	   whether mac80211 will request short-preamble transmission if the selected rate supports it

       max_rate_idx
	   user-requested maximum (legacy) rate (deprecated; this will be removed once drivers get updated to use rate_idx_mask)

       rate_idx_mask
	   user-requested (legacy) rate mask

       rate_idx_mcs_mask
	   user-requested MCS rate mask (NULL if not in use)

       bss
	   whether this frame is sent out in AP or IBSS mode

AUTHOR

       Johannes Berg <johannes@sipsolutions.net>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   STRUCT IEEE80211_TX_(9)