projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| c890063e LB |
1 | /* Copyright (c) 2017 Facebook |
| 2 | * | |
| 3 | * This program is free software; you can redistribute it and/or | |
| 4 | * modify it under the terms of version 2 of the GNU General Public | |
| 5 | * License as published by the Free Software Foundation. | |
| 6 | * | |
| 7 | * BPF program to set base_rtt to 80us when host is running TCP-NV and | |
| 8 | * both hosts are in the same datacenter (as determined by IPv6 prefix). | |
| 9 | * | |
| 10 | * Use load_sock_ops to load this BPF program. | |
| 11 | */ | |
| 12 | ||
| 13 | #include <uapi/linux/bpf.h> | |
| 14 | #include <uapi/linux/tcp.h> | |
| 15 | #include <uapi/linux/if_ether.h> | |
| 16 | #include <uapi/linux/if_packet.h> | |
| 17 | #include <uapi/linux/ip.h> | |
| 18 | #include <linux/socket.h> | |
| 19 | #include "bpf_helpers.h" | |
| 20 | #include "bpf_endian.h" | |
| 21 | ||
| 22 | #define DEBUG 1 | |
| 23 | ||
| 24 | #define bpf_printk(fmt, ...) \ | |
| 25 | ({ \ | |
| 26 | char ____fmt[] = fmt; \ | |
| 27 | bpf_trace_printk(____fmt, sizeof(____fmt), \ | |
| 28 | ##__VA_ARGS__); \ | |
| 29 | }) | |
| 30 | ||
| 31 | SEC("sockops") | |
| 32 | int bpf_basertt(struct bpf_sock_ops *skops) | |
| 33 | { | |
| 34 | char cong[20]; | |
| 35 | char nv[] = "nv"; | |
| 36 | int rv = 0, n; | |
| 37 | int op; | |
| 38 | ||
| 39 | op = (int) skops->op; | |
| 40 | ||
| 41 | #ifdef DEBUG | |
| 42 | bpf_printk("BPF command: %d\n", op); | |
| 43 | #endif | |
| 44 | ||
| 45 | /* Check if both hosts are in the same datacenter. For this | |
| 46 | * example they are if the 1st 5.5 bytes in the IPv6 address | |
| 47 | * are the same. | |
| 48 | */ | |
| 49 | if (skops->family == AF_INET6 && | |
| 50 | skops->local_ip6[0] == skops->remote_ip6[0] && | |
| 51 | (bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) == | |
| 52 | (bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) { | |
| 53 | switch (op) { | |
| 54 | case BPF_SOCK_OPS_BASE_RTT: | |
| 55 | n = bpf_getsockopt(skops, SOL_TCP, TCP_CONGESTION, | |
| 56 | cong, sizeof(cong)); | |
| 57 | if (!n && !__builtin_memcmp(cong, nv, sizeof(nv)+1)) { | |
| 58 | /* Set base_rtt to 80us */ | |
| 59 | rv = 80; | |
| 60 | } else if (n) { | |
| 61 | rv = n; | |
| 62 | } else { | |
| 63 | rv = -1; | |
| 64 | } | |
| 65 | break; | |
| 66 | default: | |
| 67 | rv = -1; | |
| 68 | } | |
| 69 | } else { | |
| 70 | rv = -1; | |
| 71 | } | |
| 72 | #ifdef DEBUG | |
| 73 | bpf_printk("Returning %d\n", rv); | |
| 74 | #endif | |
| 75 | skops->reply = rv; | |
| 76 | return 1; | |
| 77 | } | |
| 78 | char _license[] SEC("license") = "GPL"; |