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| -rw-r--r-- | samples/bpf/Makefile | 1 | ||||
| -rw-r--r-- | samples/bpf/tcp_clamp_kern.c | 102 |
2 files changed, 103 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 242d76e84a4b..9c650589e80f 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -118,6 +118,7 @@ always += tcp_rwnd_kern.o always += tcp_bufs_kern.o always += tcp_cong_kern.o always += tcp_iw_kern.o +always += tcp_clamp_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(srctree)/tools/lib/ diff --git a/samples/bpf/tcp_clamp_kern.c b/samples/bpf/tcp_clamp_kern.c new file mode 100644 index 000000000000..d68eadd9ca2d --- /dev/null +++ b/samples/bpf/tcp_clamp_kern.c @@ -0,0 +1,102 @@ +/* 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. + * + * Sample BPF program to set send and receive buffers to 150KB, sndcwnd clamp + * to 100 packets and SYN and SYN_ACK RTOs to 10ms when both hosts are within + * the same datacenter. For his example, we assume they are within the same + * datacenter when the first 5.5 bytes of their IPv6 addresses are the same. + * + * Use load_sock_ops to load this BPF program. + */ + +#include <uapi/linux/bpf.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_clamp(struct bpf_sock_ops *skops) +{ + int bufsize = 150000; + int to_init = 10; + int clamp = 100; + int rv = 0; + int op; + + /* For testing purposes, only execute rest of BPF program + * if neither port numberis 55601 + */ + if (bpf_ntohl(skops->remote_port) != 55601 && skops->local_port != 55601) + return -1; + + op = (int) skops->op; + +#ifdef DEBUG + bpf_printk("BPF command: %d\n", op); +#endif + + /* Check that both hosts are within same datacenter. For this example + * it is the case when the first 5.5 bytes of their IPv6 addresses 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_TIMEOUT_INIT: + rv = to_init; + break; + case BPF_SOCK_OPS_TCP_CONNECT_CB: + /* Set sndbuf and rcvbuf of active connections */ + rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, + &bufsize, sizeof(bufsize)); + rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, + SO_RCVBUF, &bufsize, + sizeof(bufsize)); + break; + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + rv = bpf_setsockopt(skops, SOL_TCP, + TCP_BPF_SNDCWND_CLAMP, + &clamp, sizeof(clamp)); + break; + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + /* Set sndbuf and rcvbuf of passive connections */ + rv = bpf_setsockopt(skops, SOL_TCP, + TCP_BPF_SNDCWND_CLAMP, + &clamp, sizeof(clamp)); + rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, + SO_SNDBUF, &bufsize, + sizeof(bufsize)); + rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, + SO_RCVBUF, &bufsize, + sizeof(bufsize)); + 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"; |