Function in_pcboutput_txrtlmt_locked

freebsd/netinet/in_pcb.c:3564–3612

}

int
in_pcboutput_txrtlmt_locked(struct inpcb *inp, struct ifnet *ifp, struct mbuf *mb, uint32_t max_pacing_rate)
{
	int error;

	/*
	 * If the existing send tag is for the wrong interface due to
	 * a route change, first drop the existing tag.  Set the
	 * CHANGED flag so that we will keep trying to allocate a new
	 * tag if we fail to allocate one this time.
	 */
	if (inp->inp_snd_tag != NULL && inp->inp_snd_tag->ifp != ifp) {
		in_pcbdetach_txrtlmt(inp);
		inp->inp_flags2 |= INP_RATE_LIMIT_CHANGED;
	}

	/*
	 * NOTE: When attaching to a network interface a reference is
	 * made to ensure the network interface doesn't go away until
	 * all ratelimit connections are gone. The network interface
	 * pointers compared below represent valid network interfaces,
	 * except when comparing towards NULL.
	 */
	if (max_pacing_rate == 0 && inp->inp_snd_tag == NULL) {
		error = 0;
	} else if (!(ifp->if_capenable & IFCAP_TXRTLMT)) {
		if (inp->inp_snd_tag != NULL)
			in_pcbdetach_txrtlmt(inp);
		error = 0;
	} else if (inp->inp_snd_tag == NULL) {
		/*
		 * In order to utilize packet pacing with RSS, we need
		 * to wait until there is a valid RSS hash before we
		 * can proceed:
		 */
		if (M_HASHTYPE_GET(mb) == M_HASHTYPE_NONE) {
			error = EAGAIN;
		} else {
			error = in_pcbattach_txrtlmt(inp, ifp, M_HASHTYPE_GET(mb),
			    mb->m_pkthdr.flowid, max_pacing_rate, &inp->inp_snd_tag);
		}
	} else {
		error = in_pcbmodify_txrtlmt(inp, max_pacing_rate);
	}
	if (error == 0 || error == EOPNOTSUPP)
		inp->inp_flags2 &= ~INP_RATE_LIMIT_CHANGED;

	return (error);
}

/*
 * This function should be called when the INP_RATE_LIMIT_CHANGED flag