1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __BPF_TCP_HELPERS_H 3 #define __BPF_TCP_HELPERS_H 4 5 #include <stdbool.h> 6 #include <linux/types.h> 7 #include <bpf/bpf_helpers.h> 8 #include <bpf/bpf_core_read.h> 9 #include <bpf/bpf_tracing.h> 10 11 #define BPF_STRUCT_OPS(name, args...) \ 12 SEC("struct_ops/"#name) \ 13 BPF_PROG(name, args) 14 15 #define tcp_jiffies32 ((__u32)bpf_jiffies64()) 16 17 struct sock_common { 18 unsigned char skc_state; 19 __u16 skc_num; 20 } __attribute__((preserve_access_index)); 21 22 enum sk_pacing { 23 SK_PACING_NONE = 0, 24 SK_PACING_NEEDED = 1, 25 SK_PACING_FQ = 2, 26 }; 27 28 struct sock { 29 struct sock_common __sk_common; 30 unsigned long sk_pacing_rate; 31 __u32 sk_pacing_status; /* see enum sk_pacing */ 32 } __attribute__((preserve_access_index)); 33 34 struct inet_sock { 35 struct sock sk; 36 } __attribute__((preserve_access_index)); 37 38 struct inet_connection_sock { 39 struct inet_sock icsk_inet; 40 __u8 icsk_ca_state:6, 41 icsk_ca_setsockopt:1, 42 icsk_ca_dst_locked:1; 43 struct { 44 __u8 pending; 45 } icsk_ack; 46 __u64 icsk_ca_priv[104 / sizeof(__u64)]; 47 } __attribute__((preserve_access_index)); 48 49 struct request_sock { 50 struct sock_common __req_common; 51 } __attribute__((preserve_access_index)); 52 53 struct tcp_sock { 54 struct inet_connection_sock inet_conn; 55 56 __u32 rcv_nxt; 57 __u32 snd_nxt; 58 __u32 snd_una; 59 __u8 ecn_flags; 60 __u32 delivered; 61 __u32 delivered_ce; 62 __u32 snd_cwnd; 63 __u32 snd_cwnd_cnt; 64 __u32 snd_cwnd_clamp; 65 __u32 snd_ssthresh; 66 __u8 syn_data:1, /* SYN includes data */ 67 syn_fastopen:1, /* SYN includes Fast Open option */ 68 syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */ 69 syn_fastopen_ch:1, /* Active TFO re-enabling probe */ 70 syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ 71 save_syn:1, /* Save headers of SYN packet */ 72 is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */ 73 syn_smc:1; /* SYN includes SMC */ 74 __u32 max_packets_out; 75 __u32 lsndtime; 76 __u32 prior_cwnd; 77 __u64 tcp_mstamp; /* most recent packet received/sent */ 78 } __attribute__((preserve_access_index)); 79 80 static __always_inline struct inet_connection_sock *inet_csk(const struct sock *sk) 81 { 82 return (struct inet_connection_sock *)sk; 83 } 84 85 static __always_inline void *inet_csk_ca(const struct sock *sk) 86 { 87 return (void *)inet_csk(sk)->icsk_ca_priv; 88 } 89 90 static __always_inline struct tcp_sock *tcp_sk(const struct sock *sk) 91 { 92 return (struct tcp_sock *)sk; 93 } 94 95 static __always_inline bool before(__u32 seq1, __u32 seq2) 96 { 97 return (__s32)(seq1-seq2) < 0; 98 } 99 #define after(seq2, seq1) before(seq1, seq2) 100 101 #define TCP_ECN_OK 1 102 #define TCP_ECN_QUEUE_CWR 2 103 #define TCP_ECN_DEMAND_CWR 4 104 #define TCP_ECN_SEEN 8 105 106 enum inet_csk_ack_state_t { 107 ICSK_ACK_SCHED = 1, 108 ICSK_ACK_TIMER = 2, 109 ICSK_ACK_PUSHED = 4, 110 ICSK_ACK_PUSHED2 = 8, 111 ICSK_ACK_NOW = 16 /* Send the next ACK immediately (once) */ 112 }; 113 114 enum tcp_ca_event { 115 CA_EVENT_TX_START = 0, 116 CA_EVENT_CWND_RESTART = 1, 117 CA_EVENT_COMPLETE_CWR = 2, 118 CA_EVENT_LOSS = 3, 119 CA_EVENT_ECN_NO_CE = 4, 120 CA_EVENT_ECN_IS_CE = 5, 121 }; 122 123 struct ack_sample { 124 __u32 pkts_acked; 125 __s32 rtt_us; 126 __u32 in_flight; 127 } __attribute__((preserve_access_index)); 128 129 struct rate_sample { 130 __u64 prior_mstamp; /* starting timestamp for interval */ 131 __u32 prior_delivered; /* tp->delivered at "prior_mstamp" */ 132 __s32 delivered; /* number of packets delivered over interval */ 133 long interval_us; /* time for tp->delivered to incr "delivered" */ 134 __u32 snd_interval_us; /* snd interval for delivered packets */ 135 __u32 rcv_interval_us; /* rcv interval for delivered packets */ 136 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */ 137 int losses; /* number of packets marked lost upon ACK */ 138 __u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */ 139 __u32 prior_in_flight; /* in flight before this ACK */ 140 bool is_app_limited; /* is sample from packet with bubble in pipe? */ 141 bool is_retrans; /* is sample from retransmission? */ 142 bool is_ack_delayed; /* is this (likely) a delayed ACK? */ 143 } __attribute__((preserve_access_index)); 144 145 #define TCP_CA_NAME_MAX 16 146 #define TCP_CONG_NEEDS_ECN 0x2 147 148 struct tcp_congestion_ops { 149 char name[TCP_CA_NAME_MAX]; 150 __u32 flags; 151 152 /* initialize private data (optional) */ 153 void (*init)(struct sock *sk); 154 /* cleanup private data (optional) */ 155 void (*release)(struct sock *sk); 156 157 /* return slow start threshold (required) */ 158 __u32 (*ssthresh)(struct sock *sk); 159 /* do new cwnd calculation (required) */ 160 void (*cong_avoid)(struct sock *sk, __u32 ack, __u32 acked); 161 /* call before changing ca_state (optional) */ 162 void (*set_state)(struct sock *sk, __u8 new_state); 163 /* call when cwnd event occurs (optional) */ 164 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 165 /* call when ack arrives (optional) */ 166 void (*in_ack_event)(struct sock *sk, __u32 flags); 167 /* new value of cwnd after loss (required) */ 168 __u32 (*undo_cwnd)(struct sock *sk); 169 /* hook for packet ack accounting (optional) */ 170 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample); 171 /* override sysctl_tcp_min_tso_segs */ 172 __u32 (*min_tso_segs)(struct sock *sk); 173 /* returns the multiplier used in tcp_sndbuf_expand (optional) */ 174 __u32 (*sndbuf_expand)(struct sock *sk); 175 /* call when packets are delivered to update cwnd and pacing rate, 176 * after all the ca_state processing. (optional) 177 */ 178 void (*cong_control)(struct sock *sk, const struct rate_sample *rs); 179 }; 180 181 #define min(a, b) ((a) < (b) ? (a) : (b)) 182 #define max(a, b) ((a) > (b) ? (a) : (b)) 183 #define min_not_zero(x, y) ({ \ 184 typeof(x) __x = (x); \ 185 typeof(y) __y = (y); \ 186 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 187 188 static __always_inline __u32 tcp_slow_start(struct tcp_sock *tp, __u32 acked) 189 { 190 __u32 cwnd = min(tp->snd_cwnd + acked, tp->snd_ssthresh); 191 192 acked -= cwnd - tp->snd_cwnd; 193 tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp); 194 195 return acked; 196 } 197 198 static __always_inline bool tcp_in_slow_start(const struct tcp_sock *tp) 199 { 200 return tp->snd_cwnd < tp->snd_ssthresh; 201 } 202 203 static __always_inline bool tcp_is_cwnd_limited(const struct sock *sk) 204 { 205 const struct tcp_sock *tp = tcp_sk(sk); 206 207 /* If in slow start, ensure cwnd grows to twice what was ACKed. */ 208 if (tcp_in_slow_start(tp)) 209 return tp->snd_cwnd < 2 * tp->max_packets_out; 210 211 return !!BPF_CORE_READ_BITFIELD(tp, is_cwnd_limited); 212 } 213 214 static __always_inline void tcp_cong_avoid_ai(struct tcp_sock *tp, __u32 w, __u32 acked) 215 { 216 /* If credits accumulated at a higher w, apply them gently now. */ 217 if (tp->snd_cwnd_cnt >= w) { 218 tp->snd_cwnd_cnt = 0; 219 tp->snd_cwnd++; 220 } 221 222 tp->snd_cwnd_cnt += acked; 223 if (tp->snd_cwnd_cnt >= w) { 224 __u32 delta = tp->snd_cwnd_cnt / w; 225 226 tp->snd_cwnd_cnt -= delta * w; 227 tp->snd_cwnd += delta; 228 } 229 tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_cwnd_clamp); 230 } 231 232 #endif 233