diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index d83f95ea6a1b283fa12e02099f4788f6755f2c5b..f650346aaa1a75c35094ec2202d36115ba2d6cdd 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -613,12 +613,22 @@ union bpf_attr { * int bpf_setsockopt(bpf_socket, level, optname, optval, optlen) * Calls setsockopt. Not all opts are available, only those with * integer optvals plus TCP_CONGESTION. - * Supported levels: SOL_SOCKET and IPROTO_TCP + * Supported levels: SOL_SOCKET and IPPROTO_TCP * @bpf_socket: pointer to bpf_socket - * @level: SOL_SOCKET or IPROTO_TCP + * @level: SOL_SOCKET or IPPROTO_TCP * @optname: option name * @optval: pointer to option value - * @optlen: length of optval in byes + * @optlen: length of optval in bytes + * Return: 0 or negative error + * + * int bpf_getsockopt(bpf_socket, level, optname, optval, optlen) + * Calls getsockopt. Not all opts are available. + * Supported levels: IPPROTO_TCP + * @bpf_socket: pointer to bpf_socket + * @level: IPPROTO_TCP + * @optname: option name + * @optval: pointer to option value + * @optlen: length of optval in bytes * Return: 0 or negative error * * int bpf_skb_adjust_room(skb, len_diff, mode, flags) @@ -721,7 +731,8 @@ union bpf_attr { FN(sock_map_update), \ FN(xdp_adjust_meta), \ FN(perf_event_read_value), \ - FN(perf_prog_read_value), + FN(perf_prog_read_value), \ + FN(getsockopt), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -955,6 +966,13 @@ enum { BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control * needs ECN */ + BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is + * based on the path and may be + * dependent on the congestion control + * algorithm. In general it indicates + * a congestion threshold. RTTs above + * this indicate congestion + */ }; #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */ diff --git a/net/core/filter.c b/net/core/filter.c index 09e011f20291e48d4425434276032ed8b8457348..ccf62f44140a4a2a86f23ceccbfdc013a784f0ba 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3273,7 +3273,7 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock, static const struct bpf_func_proto bpf_setsockopt_proto = { .func = bpf_setsockopt, - .gpl_only = true, + .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_ANYTHING, @@ -3282,6 +3282,48 @@ static const struct bpf_func_proto bpf_setsockopt_proto = { .arg5_type = ARG_CONST_SIZE, }; +BPF_CALL_5(bpf_getsockopt, struct bpf_sock_ops_kern *, bpf_sock, + int, level, int, optname, char *, optval, int, optlen) +{ + struct sock *sk = bpf_sock->sk; + int ret = 0; + + if (!sk_fullsock(sk)) + goto err_clear; + +#ifdef CONFIG_INET + if (level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) { + if (optname == TCP_CONGESTION) { + struct inet_connection_sock *icsk = inet_csk(sk); + + if (!icsk->icsk_ca_ops || optlen <= 1) + goto err_clear; + strncpy(optval, icsk->icsk_ca_ops->name, optlen); + optval[optlen - 1] = 0; + } else { + goto err_clear; + } + } else { + goto err_clear; + } + return ret; +#endif +err_clear: + memset(optval, 0, optlen); + return -EINVAL; +} + +static const struct bpf_func_proto bpf_getsockopt_proto = { + .func = bpf_getsockopt, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_UNINIT_MEM, + .arg5_type = ARG_CONST_SIZE, +}; + static const struct bpf_func_proto * bpf_base_func_proto(enum bpf_func_id func_id) { @@ -3460,6 +3502,8 @@ static const struct bpf_func_proto * switch (func_id) { case BPF_FUNC_setsockopt: return &bpf_setsockopt_proto; + case BPF_FUNC_getsockopt: + return &bpf_getsockopt_proto; case BPF_FUNC_sock_map_update: return &bpf_sock_map_update_proto; default: diff --git a/net/ipv4/tcp_nv.c b/net/ipv4/tcp_nv.c index 1ff73982e28c58ecd0faa787e5ee30793e30dea8..a978e3fa71ec7b367d1c40b7ff65c488f76a21b2 100644 --- a/net/ipv4/tcp_nv.c +++ b/net/ipv4/tcp_nv.c @@ -39,7 +39,7 @@ * nv_cong_dec_mult Decrease cwnd by X% (30%) of congestion when detected * nv_ssthresh_factor On congestion set ssthresh to this * / 8 * nv_rtt_factor RTT averaging factor - * nv_loss_dec_factor Decrease cwnd by this (50%) when losses occur + * nv_loss_dec_factor Decrease cwnd to this (80%) when losses occur * nv_dec_eval_min_calls Wait this many RTT measurements before dec cwnd * nv_inc_eval_min_calls Wait this many RTT measurements before inc cwnd * nv_ssthresh_eval_min_calls Wait this many RTT measurements before stopping @@ -61,7 +61,7 @@ static int nv_min_cwnd __read_mostly = 2; static int nv_cong_dec_mult __read_mostly = 30 * 128 / 100; /* = 30% */ static int nv_ssthresh_factor __read_mostly = 8; /* = 1 */ static int nv_rtt_factor __read_mostly = 128; /* = 1/2*old + 1/2*new */ -static int nv_loss_dec_factor __read_mostly = 512; /* => 50% */ +static int nv_loss_dec_factor __read_mostly = 819; /* => 80% */ static int nv_cwnd_growth_rate_neg __read_mostly = 8; static int nv_cwnd_growth_rate_pos __read_mostly; /* 0 => fixed like Reno */ static int nv_dec_eval_min_calls __read_mostly = 60; @@ -101,6 +101,11 @@ struct tcpnv { u32 nv_last_rtt; /* last rtt */ u32 nv_min_rtt; /* active min rtt. Used to determine slope */ u32 nv_min_rtt_new; /* min rtt for future use */ + u32 nv_base_rtt; /* If non-zero it represents the threshold for + * congestion */ + u32 nv_lower_bound_rtt; /* Used in conjunction with nv_base_rtt. It is + * set to 80% of nv_base_rtt. It helps reduce + * unfairness between flows */ u32 nv_rtt_max_rate; /* max rate seen during current RTT */ u32 nv_rtt_start_seq; /* current RTT ends when packet arrives * acking beyond nv_rtt_start_seq */ @@ -132,9 +137,24 @@ static inline void tcpnv_reset(struct tcpnv *ca, struct sock *sk) static void tcpnv_init(struct sock *sk) { struct tcpnv *ca = inet_csk_ca(sk); + int base_rtt; tcpnv_reset(ca, sk); + /* See if base_rtt is available from socket_ops bpf program. + * It is meant to be used in environments, such as communication + * within a datacenter, where we have reasonable estimates of + * RTTs + */ + base_rtt = tcp_call_bpf(sk, BPF_SOCK_OPS_BASE_RTT); + if (base_rtt > 0) { + ca->nv_base_rtt = base_rtt; + ca->nv_lower_bound_rtt = (base_rtt * 205) >> 8; /* 80% */ + } else { + ca->nv_base_rtt = 0; + ca->nv_lower_bound_rtt = 0; + } + ca->nv_allow_cwnd_growth = 1; ca->nv_min_rtt_reset_jiffies = jiffies + 2 * HZ; ca->nv_min_rtt = NV_INIT_RTT; @@ -144,6 +164,19 @@ static void tcpnv_init(struct sock *sk) ca->cwnd_growth_factor = 0; } +/* If provided, apply upper (base_rtt) and lower (lower_bound_rtt) + * bounds to RTT. + */ +inline u32 nv_get_bounded_rtt(struct tcpnv *ca, u32 val) +{ + if (ca->nv_lower_bound_rtt > 0 && val < ca->nv_lower_bound_rtt) + return ca->nv_lower_bound_rtt; + else if (ca->nv_base_rtt > 0 && val > ca->nv_base_rtt) + return ca->nv_base_rtt; + else + return val; +} + static void tcpnv_cong_avoid(struct sock *sk, u32 ack, u32 acked) { struct tcp_sock *tp = tcp_sk(sk); @@ -265,6 +298,9 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) if (ca->nv_eval_call_cnt < 255) ca->nv_eval_call_cnt++; + /* Apply bounds to rtt. Only used to update min_rtt */ + avg_rtt = nv_get_bounded_rtt(ca, avg_rtt); + /* update min rtt if necessary */ if (avg_rtt < ca->nv_min_rtt) ca->nv_min_rtt = avg_rtt; diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 3534ccfb5920975823c2188e16b0fda507008713..ea2b9e6135f3cdd45f1e44e99a53fe95c786e64b 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -129,6 +129,7 @@ always += tcp_bufs_kern.o always += tcp_cong_kern.o always += tcp_iw_kern.o always += tcp_clamp_kern.o +always += tcp_basertt_kern.o always += xdp_redirect_kern.o always += xdp_redirect_map_kern.o always += xdp_redirect_cpu_kern.o diff --git a/samples/bpf/tcp_basertt_kern.c b/samples/bpf/tcp_basertt_kern.c new file mode 100644 index 0000000000000000000000000000000000000000..4bf4fc597db9a616da5f21669201357b293e542c --- /dev/null +++ b/samples/bpf/tcp_basertt_kern.c @@ -0,0 +1,78 @@ +/* Copyright (c) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * BPF program to set base_rtt to 80us when host is running TCP-NV and + * both hosts are in the same datacenter (as determined by IPv6 prefix). + * + * Use load_sock_ops to load this BPF program. + */ + +#include +#include +#include +#include +#include +#include +#include "bpf_helpers.h" +#include "bpf_endian.h" + +#define DEBUG 1 + +#define bpf_printk(fmt, ...) \ +({ \ + char ____fmt[] = fmt; \ + bpf_trace_printk(____fmt, sizeof(____fmt), \ + ##__VA_ARGS__); \ +}) + +SEC("sockops") +int bpf_basertt(struct bpf_sock_ops *skops) +{ + char cong[20]; + char nv[] = "nv"; + int rv = 0, n; + int op; + + op = (int) skops->op; + +#ifdef DEBUG + bpf_printk("BPF command: %d\n", op); +#endif + + /* Check if both hosts are in the same datacenter. For this + * example they are if the 1st 5.5 bytes in the IPv6 address + * are the same. + */ + if (skops->family == AF_INET6 && + skops->local_ip6[0] == skops->remote_ip6[0] && + (bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) == + (bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) { + switch (op) { + case BPF_SOCK_OPS_BASE_RTT: + n = bpf_getsockopt(skops, SOL_TCP, TCP_CONGESTION, + cong, sizeof(cong)); + if (!n && !__builtin_memcmp(cong, nv, sizeof(nv)+1)) { + /* Set base_rtt to 80us */ + rv = 80; + } else if (n) { + rv = n; + } else { + rv = -1; + } + break; + default: + rv = -1; + } + } else { + rv = -1; + } +#ifdef DEBUG + bpf_printk("Returning %d\n", rv); +#endif + skops->reply = rv; + return 1; +} +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/tcp_bbf.readme b/samples/bpf/tcp_bbf.readme new file mode 100644 index 0000000000000000000000000000000000000000..831fb601e3c97e872c3487eafda9aef2551630ba --- /dev/null +++ b/samples/bpf/tcp_bbf.readme @@ -0,0 +1,26 @@ +This file describes how to run the tcp_*_kern.o tcp_bpf (or socket_ops) +programs. These programs attach to a cgroupv2. The following commands create +a cgroupv2 and attach a bash shell to the group. + + mkdir -p /tmp/cgroupv2 + mount -t cgroup2 none /tmp/cgroupv2 + mkdir -p /tmp/cgroupv2/foo + bash + echo $$ >> /tmp/cgroupv2/foo/cgroup.procs + +Anything that runs under this shell belongs to the foo cgroupv2 To load +(attach) one of the tcp_*_kern.o programs: + + ./load_sock_ops -l /tmp/cgroupv2/foo tcp_basertt_kern.o + +If the "-l" flag is used, the load_sock_ops program will continue to run +printing the BPF log buffer. The tcp_*_kern.o programs use special print +functions to print logging information (if enabled by the ifdef). + +If using netperf/netserver to create traffic, you need to run them under the +cgroupv2 to which the BPF programs are attached (i.e. under bash shell +attached to the cgroupv2). + +To remove (unattach) a socket_ops BPF program from a cgroupv2: + + ./load_sock_ops -r /tmp/cgroupv2/foo diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index e25dbf6038cf6d9ea8afb0d2db2fd7acd1b46d0f..609514f7448254e976c2b7d0b58cb20a24b19365 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -67,6 +67,9 @@ static int (*bpf_xdp_adjust_meta)(void *ctx, int offset) = static int (*bpf_setsockopt)(void *ctx, int level, int optname, void *optval, int optlen) = (void *) BPF_FUNC_setsockopt; +static int (*bpf_getsockopt)(void *ctx, int level, int optname, void *optval, + int optlen) = + (void *) BPF_FUNC_getsockopt; static int (*bpf_sk_redirect_map)(void *map, int key, int flags) = (void *) BPF_FUNC_sk_redirect_map; static int (*bpf_sock_map_update)(void *map, void *key, void *value,