samples/bpf/hbm_out_kern.c

1 // SPDX-License-Identifier: GPL-2.0
4  * This program is free software; you can redistribute it and/or
10  * A cgroup skb BPF egress program to limit cgroup output bandwidth.
11  * It uses a modified virtual token bucket queue to limit average
20  *        - <--------------------------|------------------------> +
45  * The default bandwidth limit is set at 1Gbps but this can be changed by
47  * program does not limit connections using loopback. This behavior can be
49  * some statistics, such as percent of packets marked or dropped, which
61 	int len = skb->len;  in _hbm_out_cg()  local
76 	if (qsp != NULL && !qsp->loopback && (skb->ifindex == 1))  in _hbm_out_cg()
81 	// We may want to account for the length of headers in len  in _hbm_out_cg()
88 	else if (qdp->lasttime == 0)  in _hbm_out_cg()
94 	bpf_spin_lock(&qdp->lock);  in _hbm_out_cg()
95 	credit = qdp->credit;  in _hbm_out_cg()
96 	delta = curtime - qdp->lasttime;  in _hbm_out_cg()
102 		qdp->lasttime = curtime;  in _hbm_out_cg()
103 		new_credit = credit + CREDIT_PER_NS(delta, qdp->rate);  in _hbm_out_cg()
109 	credit -= len;  in _hbm_out_cg()
110 	qdp->credit = credit;  in _hbm_out_cg()
111 	bpf_spin_unlock(&qdp->lock);  in _hbm_out_cg()
115 	if (qsp != NULL && (qsp->rate * 128) != qdp->rate) {  in _hbm_out_cg()
116 		qdp->rate = qsp->rate * 128;  in _hbm_out_cg()
118 			   (int)qdp->rate,  in _hbm_out_cg()
119 			   CREDIT_PER_NS(1000000000, qdp->rate) * 8);  in _hbm_out_cg()
124 	if (credit < -DROP_THRESH ||  in _hbm_out_cg()
125 	    (len > LARGE_PKT_THRESH && credit < -LARGE_PKT_DROP_THRESH)) {  in _hbm_out_cg()
135 			if (credit < -MARK_THRESH)  in _hbm_out_cg()
151 				if (-credit >= MARK_THRESH +  in _hbm_out_cg()
156 			} else if (len > LARGE_PKT_THRESH) {  in _hbm_out_cg()
164 		if (qsp->no_cn)  in _hbm_out_cg()
167 	hbm_update_stats(qsp, len, curtime, congestion_flag, drop_flag,  in _hbm_out_cg()
171 		__sync_add_and_fetch(&(qdp->credit), len);  in _hbm_out_cg()