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-rw-r--r--include/uapi/linux/bpf.h26
-rw-r--r--net/core/filter.c46
-rw-r--r--net/ipv4/tcp_nv.c40
-rw-r--r--samples/bpf/Makefile1
-rw-r--r--samples/bpf/tcp_basertt_kern.c78
-rw-r--r--samples/bpf/tcp_bbf.readme26
-rw-r--r--tools/testing/selftests/bpf/bpf_helpers.h3
7 files changed, 213 insertions, 7 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d83f95ea6a1b..f650346aaa1a 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 09e011f20291..ccf62f44140a 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 1ff73982e28c..a978e3fa71ec 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 * <desired cwnd> / 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 3534ccfb5920..ea2b9e6135f3 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 000000000000..4bf4fc597db9
--- /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 <uapi/linux/bpf.h>
+#include <uapi/linux/tcp.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include <linux/socket.h>
+#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 000000000000..831fb601e3c9
--- /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 e25dbf6038cf..609514f74482 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,
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