projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| c400296b 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 initial receive window to 40 packets when using IPv6 | |
| 8 | * and the first 5.5 bytes of the IPv6 addresses are not the same (in this | |
| 9 | * example that means both hosts are not the same datacenter). | |
| 10 | * | |
| 11 | * Use load_sock_ops to load this BPF program. | |
| 12 | */ | |
| 13 | ||
| 14 | #include <uapi/linux/bpf.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_rwnd(struct bpf_sock_ops *skops) | |
| 33 | { | |
| 34 | int rv = -1; | |
| 35 | int op; | |
| 36 | ||
| 37 | /* For testing purposes, only execute rest of BPF program | |
| 38 | * if neither port numberis 55601 | |
| 39 | */ | |
| 40 | if (bpf_ntohl(skops->remote_port) != | |
| 016e661b LB |
41 | 55601 && skops->local_port != 55601) { |
| 42 | skops->reply = -1; | |
| 43 | return 1; | |
| 44 | } | |
| c400296b LB |
45 | |
| 46 | op = (int) skops->op; | |
| 47 | ||
| 48 | #ifdef DEBUG | |
| 49 | bpf_printk("BPF command: %d\n", op); | |
| 50 | #endif | |
| 51 | ||
| 52 | /* Check for RWND_INIT operation and IPv6 addresses */ | |
| 53 | if (op == BPF_SOCK_OPS_RWND_INIT && | |
| 54 | skops->family == AF_INET6) { | |
| 55 | ||
| 56 | /* If the first 5.5 bytes of the IPv6 address are not the same | |
| 57 | * then both hosts are not in the same datacenter | |
| 58 | * so use a larger initial advertized window (40 packets) | |
| 59 | */ | |
| 60 | if (skops->local_ip6[0] != skops->remote_ip6[0] || | |
| 61 | (bpf_ntohl(skops->local_ip6[1]) & 0xfffff000) != | |
| 62 | (bpf_ntohl(skops->remote_ip6[1]) & 0xfffff000)) | |
| 63 | rv = 40; | |
| 64 | } | |
| 65 | #ifdef DEBUG | |
| 66 | bpf_printk("Returning %d\n", rv); | |
| 67 | #endif | |
| 68 | skops->reply = rv; | |
| 69 | return 1; | |
| 70 | } | |
| 71 | char _license[] SEC("license") = "GPL"; |