samples/bpf/hbm_kern.h

   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 }