1 /* SPDX-License-Identifier: GPL-2.0
2 *
3 * Copyright (c) 2019 Facebook
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * Include file for sample Host Bandwidth Manager (HBM) BPF programs
10 */
11 #define KBUILD_MODNAME "foo"
12 #include <uapi/linux/bpf.h>
13 #include <uapi/linux/if_ether.h>
14 #include <uapi/linux/if_packet.h>
15 #include <uapi/linux/ip.h>
16 #include <uapi/linux/ipv6.h>
17 #include <uapi/linux/in.h>
18 #include <uapi/linux/tcp.h>
19 #include <uapi/linux/filter.h>
20 #include <uapi/linux/pkt_cls.h>
21 #include <net/ipv6.h>
22 #include <net/inet_ecn.h>
23 #include <bpf/bpf_endian.h>
24 #include <bpf/bpf_helpers.h>
25 #include "hbm.h"
26
27 #define DROP_PKT 0
28 #define ALLOW_PKT 1
29 #define TCP_ECN_OK 1
30 #define CWR 2
31
32 #ifndef HBM_DEBUG // Define HBM_DEBUG to enable debugging
33 #undef bpf_printk
34 #define bpf_printk(fmt, ...)
35 #endif
36
37 #define INITIAL_CREDIT_PACKETS 100
38 #define MAX_BYTES_PER_PACKET 1500
39 #define MARK_THRESH (40 * MAX_BYTES_PER_PACKET)
40 #define DROP_THRESH (80 * 5 * MAX_BYTES_PER_PACKET)
41 #define LARGE_PKT_DROP_THRESH (DROP_THRESH - (15 * MAX_BYTES_PER_PACKET))
42 #define MARK_REGION_SIZE (LARGE_PKT_DROP_THRESH - MARK_THRESH)
43 #define LARGE_PKT_THRESH 120
44 #define MAX_CREDIT (100 * MAX_BYTES_PER_PACKET)
45 #define INIT_CREDIT (INITIAL_CREDIT_PACKETS * MAX_BYTES_PER_PACKET)
46
47 // Time base accounting for fq's EDT
48 #define BURST_SIZE_NS 100000 // 100us
49 #define MARK_THRESH_NS 50000 // 50us
50 #define DROP_THRESH_NS 500000 // 500us
51 // Reserve 20us of queuing for small packets (less than 120 bytes)
52 #define LARGE_PKT_DROP_THRESH_NS (DROP_THRESH_NS - 20000)
53 #define MARK_REGION_SIZE_NS (LARGE_PKT_DROP_THRESH_NS - MARK_THRESH_NS)
54
55 // rate in bytes per ns << 20
56 #define CREDIT_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
57 #define BYTES_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
58 #define BYTES_TO_NS(bytes, rate) div64_u64(((u64)(bytes)) << 20, (u64)(rate))
59
60 struct {
61 __uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
62 __type(key, struct bpf_cgroup_storage_key);
63 __type(value, struct hbm_vqueue);
64 } queue_state SEC(".maps");
65
66 struct {
67 __uint(type, BPF_MAP_TYPE_ARRAY);
68 __uint(max_entries, 1);
69 __type(key, u32);
70 __type(value, struct hbm_queue_stats);
71 } queue_stats SEC(".maps");
72
73 struct hbm_pkt_info {
74 int cwnd;
75 int rtt;
76 int packets_out;
77 bool is_ip;
78 bool is_tcp;
79 short ecn;
80 };
81
82 static int get_tcp_info(struct __sk_buff *skb, struct hbm_pkt_info *pkti)
83 {
84 struct bpf_sock *sk;
85 struct bpf_tcp_sock *tp;
86
87 sk = skb->sk;
88 if (sk) {
89 sk = bpf_sk_fullsock(sk);
90 if (sk) {
91 if (sk->protocol == IPPROTO_TCP) {
92 tp = bpf_tcp_sock(sk);
93 if (tp) {
94 pkti->cwnd = tp->snd_cwnd;
95 pkti->rtt = tp->srtt_us >> 3;
96 pkti->packets_out = tp->packets_out;
97 return 0;
98 }
99 }
100 }
101 }
102 pkti->cwnd = 0;
103 pkti->rtt = 0;
104 pkti->packets_out = 0;
105 return 1;
106 }
107
108 static void hbm_get_pkt_info(struct __sk_buff *skb,
109 struct hbm_pkt_info *pkti)
110 {
111 struct iphdr iph;
112 struct ipv6hdr *ip6h;
113
114 pkti->cwnd = 0;
115 pkti->rtt = 0;
116 bpf_skb_load_bytes(skb, 0, &iph, 12);
117 if (iph.version == 6) {
118 ip6h = (struct ipv6hdr *)&iph;
119 pkti->is_ip = true;
120 pkti->is_tcp = (ip6h->nexthdr == 6);
121 pkti->ecn = (ip6h->flow_lbl[0] >> 4) & INET_ECN_MASK;
122 } else if (iph.version == 4) {
123 pkti->is_ip = true;
124 pkti->is_tcp = (iph.protocol == 6);
125 pkti->ecn = iph.tos & INET_ECN_MASK;
126 } else {
127 pkti->is_ip = false;
128 pkti->is_tcp = false;
129 pkti->ecn = 0;
130 }
131 if (pkti->is_tcp)
132 get_tcp_info(skb, pkti);
133 }
134
135 static __always_inline void hbm_init_vqueue(struct hbm_vqueue *qdp, int rate)
136 {
137 bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
138 qdp->lasttime = bpf_ktime_get_ns();
139 qdp->credit = INIT_CREDIT;
140 qdp->rate = rate * 128;
141 }
142
143 static __always_inline void hbm_init_edt_vqueue(struct hbm_vqueue *qdp,
144 int rate)
145 {
146 unsigned long long curtime;
147
148 curtime = bpf_ktime_get_ns();
149 bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
150 qdp->lasttime = curtime - BURST_SIZE_NS; // support initial burst
151 qdp->credit = 0; // not used
152 qdp->rate = rate * 128;
153 }
154
155 static __always_inline void hbm_update_stats(struct hbm_queue_stats *qsp,
156 int len,
157 unsigned long long curtime,
158 bool congestion_flag,
159 bool drop_flag,
160 bool cwr_flag,
161 bool ecn_ce_flag,
162 struct hbm_pkt_info *pkti,
163 int credit)
164 {
165 int rv = ALLOW_PKT;
166
167 if (qsp != NULL) {
168 // Following is needed for work conserving
169 __sync_add_and_fetch(&(qsp->bytes_total), len);
170 if (qsp->stats) {
171 // Optionally update statistics
172 if (qsp->firstPacketTime == 0)
173 qsp->firstPacketTime = curtime;
174 qsp->lastPacketTime = curtime;
175 __sync_add_and_fetch(&(qsp->pkts_total), 1);
176 if (congestion_flag) {
177 __sync_add_and_fetch(&(qsp->pkts_marked), 1);
178 __sync_add_and_fetch(&(qsp->bytes_marked), len);
179 }
180 if (drop_flag) {
181 __sync_add_and_fetch(&(qsp->pkts_dropped), 1);
182 __sync_add_and_fetch(&(qsp->bytes_dropped),
183 len);
184 }
185 if (ecn_ce_flag)
186 __sync_add_and_fetch(&(qsp->pkts_ecn_ce), 1);
187 if (pkti->cwnd) {
188 __sync_add_and_fetch(&(qsp->sum_cwnd),
189 pkti->cwnd);
190 __sync_add_and_fetch(&(qsp->sum_cwnd_cnt), 1);
191 }
192 if (pkti->rtt)
193 __sync_add_and_fetch(&(qsp->sum_rtt),
194 pkti->rtt);
195 __sync_add_and_fetch(&(qsp->sum_credit), credit);
196
197 if (drop_flag)
198 rv = DROP_PKT;
199 if (cwr_flag)
200 rv |= 2;
201 if (rv == DROP_PKT)
202 __sync_add_and_fetch(&(qsp->returnValCount[0]),
203 1);
204 else if (rv == ALLOW_PKT)
205 __sync_add_and_fetch(&(qsp->returnValCount[1]),
206 1);
207 else if (rv == 2)
208 __sync_add_and_fetch(&(qsp->returnValCount[2]),
209 1);
210 else if (rv == 3)
211 __sync_add_and_fetch(&(qsp->returnValCount[3]),
212 1);
213 }
214 }
215 }
216
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