samples/bpf/hbm_edt_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
68 	int len = skb->len;  in _hbm_out_cg()  local
74 	if (qsp != NULL && !qsp->loopback && (skb->ifindex == 1))  in _hbm_out_cg()
79 	// We may want to account for the length of headers in len  in _hbm_out_cg()
86 	if (qdp->lasttime == 0)  in _hbm_out_cg()
92 	bpf_spin_lock(&qdp->lock);  in _hbm_out_cg()
93 	delta = qdp->lasttime - curtime;  in _hbm_out_cg()
95 	if (delta < -BURST_SIZE_NS) {  in _hbm_out_cg()
97 		qdp->lasttime = curtime - BURST_SIZE_NS;  in _hbm_out_cg()
98 		delta = -BURST_SIZE_NS;  in _hbm_out_cg()
100 	sendtime = qdp->lasttime;  in _hbm_out_cg()
101 	delta_send = BYTES_TO_NS(len, qdp->rate);  in _hbm_out_cg()
102 	__sync_add_and_fetch(&(qdp->lasttime), delta_send);  in _hbm_out_cg()
103 	bpf_spin_unlock(&qdp->lock);  in _hbm_out_cg()
107 	skb->tstamp = sendtime;  in _hbm_out_cg()
110 	if (qsp != NULL && (qsp->rate * 128) != qdp->rate)  in _hbm_out_cg()
111 		qdp->rate = qsp->rate * 128;  in _hbm_out_cg()
116 				       len > LARGE_PKT_THRESH)) {  in _hbm_out_cg()
139 			} else if (len > LARGE_PKT_THRESH) {  in _hbm_out_cg()
153 	if (qsp != NULL && qsp->no_cn)  in _hbm_out_cg()
156 	hbm_update_stats(qsp, len, curtime, congestion_flag, drop_flag,  in _hbm_out_cg()
160 		__sync_add_and_fetch(&(qdp->lasttime), -delta_send);  in _hbm_out_cg()