linux/samples/bpf/hbm_kern.h
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   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 <stddef.h>
  13#include <stdbool.h>
  14#include <uapi/linux/bpf.h>
  15#include <uapi/linux/if_ether.h>
  16#include <uapi/linux/if_packet.h>
  17#include <uapi/linux/ip.h>
  18#include <uapi/linux/ipv6.h>
  19#include <uapi/linux/in.h>
  20#include <uapi/linux/tcp.h>
  21#include <uapi/linux/filter.h>
  22#include <uapi/linux/pkt_cls.h>
  23#include <net/ipv6.h>
  24#include <net/inet_ecn.h>
  25#include "bpf_endian.h"
  26#include "bpf_helpers.h"
  27#include "hbm.h"
  28
  29#define DROP_PKT        0
  30#define ALLOW_PKT       1
  31#define TCP_ECN_OK      1
  32#define CWR             2
  33
  34#ifndef HBM_DEBUG  // Define HBM_DEBUG to enable debugging
  35#undef bpf_printk
  36#define bpf_printk(fmt, ...)
  37#endif
  38
  39#define INITIAL_CREDIT_PACKETS  100
  40#define MAX_BYTES_PER_PACKET    1500
  41#define MARK_THRESH             (40 * MAX_BYTES_PER_PACKET)
  42#define DROP_THRESH             (80 * 5 * MAX_BYTES_PER_PACKET)
  43#define LARGE_PKT_DROP_THRESH   (DROP_THRESH - (15 * MAX_BYTES_PER_PACKET))
  44#define MARK_REGION_SIZE        (LARGE_PKT_DROP_THRESH - MARK_THRESH)
  45#define LARGE_PKT_THRESH        120
  46#define MAX_CREDIT              (100 * MAX_BYTES_PER_PACKET)
  47#define INIT_CREDIT             (INITIAL_CREDIT_PACKETS * MAX_BYTES_PER_PACKET)
  48
  49// Time base accounting for fq's EDT
  50#define BURST_SIZE_NS           100000 // 100us
  51#define MARK_THRESH_NS          50000 // 50us
  52#define DROP_THRESH_NS          500000 // 500us
  53// Reserve 20us of queuing for small packets (less than 120 bytes)
  54#define LARGE_PKT_DROP_THRESH_NS (DROP_THRESH_NS - 20000)
  55#define MARK_REGION_SIZE_NS     (LARGE_PKT_DROP_THRESH_NS - MARK_THRESH_NS)
  56
  57// rate in bytes per ns << 20
  58#define CREDIT_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
  59#define BYTES_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
  60#define BYTES_TO_NS(bytes, rate) div64_u64(((u64)(bytes)) << 20, (u64)(rate))
  61
  62struct bpf_map_def SEC("maps") queue_state = {
  63        .type = BPF_MAP_TYPE_CGROUP_STORAGE,
  64        .key_size = sizeof(struct bpf_cgroup_storage_key),
  65        .value_size = sizeof(struct hbm_vqueue),
  66};
  67BPF_ANNOTATE_KV_PAIR(queue_state, struct bpf_cgroup_storage_key,
  68                     struct hbm_vqueue);
  69
  70struct bpf_map_def SEC("maps") queue_stats = {
  71        .type = BPF_MAP_TYPE_ARRAY,
  72        .key_size = sizeof(u32),
  73        .value_size = sizeof(struct hbm_queue_stats),
  74        .max_entries = 1,
  75};
  76BPF_ANNOTATE_KV_PAIR(queue_stats, int, struct hbm_queue_stats);
  77
  78struct hbm_pkt_info {
  79        int     cwnd;
  80        int     rtt;
  81        int     packets_out;
  82        bool    is_ip;
  83        bool    is_tcp;
  84        short   ecn;
  85};
  86
  87static int get_tcp_info(struct __sk_buff *skb, struct hbm_pkt_info *pkti)
  88{
  89        struct bpf_sock *sk;
  90        struct bpf_tcp_sock *tp;
  91
  92        sk = skb->sk;
  93        if (sk) {
  94                sk = bpf_sk_fullsock(sk);
  95                if (sk) {
  96                        if (sk->protocol == IPPROTO_TCP) {
  97                                tp = bpf_tcp_sock(sk);
  98                                if (tp) {
  99                                        pkti->cwnd = tp->snd_cwnd;
 100                                        pkti->rtt = tp->srtt_us >> 3;
 101                                        pkti->packets_out = tp->packets_out;
 102                                        return 0;
 103                                }
 104                        }
 105                }
 106        }
 107        pkti->cwnd = 0;
 108        pkti->rtt = 0;
 109        pkti->packets_out = 0;
 110        return 1;
 111}
 112
 113static void hbm_get_pkt_info(struct __sk_buff *skb,
 114                             struct hbm_pkt_info *pkti)
 115{
 116        struct iphdr iph;
 117        struct ipv6hdr *ip6h;
 118
 119        pkti->cwnd = 0;
 120        pkti->rtt = 0;
 121        bpf_skb_load_bytes(skb, 0, &iph, 12);
 122        if (iph.version == 6) {
 123                ip6h = (struct ipv6hdr *)&iph;
 124                pkti->is_ip = true;
 125                pkti->is_tcp = (ip6h->nexthdr == 6);
 126                pkti->ecn = (ip6h->flow_lbl[0] >> 4) & INET_ECN_MASK;
 127        } else if (iph.version == 4) {
 128                pkti->is_ip = true;
 129                pkti->is_tcp = (iph.protocol == 6);
 130                pkti->ecn = iph.tos & INET_ECN_MASK;
 131        } else {
 132                pkti->is_ip = false;
 133                pkti->is_tcp = false;
 134                pkti->ecn = 0;
 135        }
 136        if (pkti->is_tcp)
 137                get_tcp_info(skb, pkti);
 138}
 139
 140static __always_inline void hbm_init_vqueue(struct hbm_vqueue *qdp, int rate)
 141{
 142        bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
 143        qdp->lasttime = bpf_ktime_get_ns();
 144        qdp->credit = INIT_CREDIT;
 145        qdp->rate = rate * 128;
 146}
 147
 148static __always_inline void hbm_init_edt_vqueue(struct hbm_vqueue *qdp,
 149                                                int rate)
 150{
 151        unsigned long long curtime;
 152
 153        curtime = bpf_ktime_get_ns();
 154        bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
 155        qdp->lasttime = curtime - BURST_SIZE_NS;        // support initial burst
 156        qdp->credit = 0;                                // not used
 157        qdp->rate = rate * 128;
 158}
 159
 160static __always_inline void hbm_update_stats(struct hbm_queue_stats *qsp,
 161                                             int len,
 162                                             unsigned long long curtime,
 163                                             bool congestion_flag,
 164                                             bool drop_flag,
 165                                             bool cwr_flag,
 166                                             bool ecn_ce_flag,
 167                                             struct hbm_pkt_info *pkti,
 168                                             int credit)
 169{
 170        int rv = ALLOW_PKT;
 171
 172        if (qsp != NULL) {
 173                // Following is needed for work conserving
 174                __sync_add_and_fetch(&(qsp->bytes_total), len);
 175                if (qsp->stats) {
 176                        // Optionally update statistics
 177                        if (qsp->firstPacketTime == 0)
 178                                qsp->firstPacketTime = curtime;
 179                        qsp->lastPacketTime = curtime;
 180                        __sync_add_and_fetch(&(qsp->pkts_total), 1);
 181                        if (congestion_flag) {
 182                                __sync_add_and_fetch(&(qsp->pkts_marked), 1);
 183                                __sync_add_and_fetch(&(qsp->bytes_marked), len);
 184                        }
 185                        if (drop_flag) {
 186                                __sync_add_and_fetch(&(qsp->pkts_dropped), 1);
 187                                __sync_add_and_fetch(&(qsp->bytes_dropped),
 188                                                     len);
 189                        }
 190                        if (ecn_ce_flag)
 191                                __sync_add_and_fetch(&(qsp->pkts_ecn_ce), 1);
 192                        if (pkti->cwnd) {
 193                                __sync_add_and_fetch(&(qsp->sum_cwnd),
 194                                                     pkti->cwnd);
 195                                __sync_add_and_fetch(&(qsp->sum_cwnd_cnt), 1);
 196                        }
 197                        if (pkti->rtt)
 198                                __sync_add_and_fetch(&(qsp->sum_rtt),
 199                                                     pkti->rtt);
 200                        __sync_add_and_fetch(&(qsp->sum_credit), credit);
 201
 202                        if (drop_flag)
 203                                rv = DROP_PKT;
 204                        if (cwr_flag)
 205                                rv |= 2;
 206                        if (rv == DROP_PKT)
 207                                __sync_add_and_fetch(&(qsp->returnValCount[0]),
 208                                                     1);
 209                        else if (rv == ALLOW_PKT)
 210                                __sync_add_and_fetch(&(qsp->returnValCount[1]),
 211                                                     1);
 212                        else if (rv == 2)
 213                                __sync_add_and_fetch(&(qsp->returnValCount[2]),
 214                                                     1);
 215                        else if (rv == 3)
 216                                __sync_add_and_fetch(&(qsp->returnValCount[3]),
 217                                                     1);
 218                }
 219        }
 220}
 221