diff options
| -rw-r--r-- | samples/bpf/Makefile | 1 | ||||
| -rw-r--r-- | samples/bpf/tcp_cong_kern.c | 83 |
2 files changed, 84 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 3b300db3d74d..6fdf32dffa92 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -116,6 +116,7 @@ always += cookie_uid_helper_example.o always += tcp_synrto_kern.o always += tcp_rwnd_kern.o always += tcp_bufs_kern.o +always += tcp_cong_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(srctree)/tools/lib/ diff --git a/samples/bpf/tcp_cong_kern.c b/samples/bpf/tcp_cong_kern.c new file mode 100644 index 000000000000..dac15bce1fa9 --- /dev/null +++ b/samples/bpf/tcp_cong_kern.c @@ -0,0 +1,83 @@ +/* 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 congestion control to dctcp when both hosts are + * in the same datacenter (as deteremined 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_cong(struct bpf_sock_ops *skops) +{ + char cong[] = "dctcp"; + 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 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_NEEDS_ECN: + rv = 1; + break; + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + rv = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION, + cong, sizeof(cong)); + break; + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + rv = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION, + cong, sizeof(cong)); + 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"; |