^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* Copyright (c) 2017 Facebook
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * This program is free software; you can redistribute it and/or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * modify it under the terms of version 2 of the GNU General Public
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * License as published by the Free Software Foundation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * BPF program to set initial congestion window and initial receive
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * window to 40 packets and send and receive buffers to 1.5MB. This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * would usually be done after doing appropriate checks that indicate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * the hosts are far enough away (i.e. large RTT).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <uapi/linux/bpf.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <uapi/linux/if_ether.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <uapi/linux/if_packet.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <uapi/linux/ip.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/socket.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <bpf/bpf_helpers.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #include <bpf/bpf_endian.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #define DEBUG 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) SEC("sockops")
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) int bpf_iw(struct bpf_sock_ops *skops)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) int bufsize = 1500000;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) int rwnd_init = 40;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) int iw = 40;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) int rv = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) int op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) /* For testing purposes, only execute rest of BPF program
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * if neither port numberis 55601
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) if (bpf_ntohl(skops->remote_port) != 55601 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) skops->local_port != 55601) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) skops->reply = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) op = (int) skops->op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) #ifdef DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) bpf_printk("BPF command: %d\n", op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) /* Usually there would be a check to insure the hosts are far
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * from each other so it makes sense to increase buffer sizes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) switch (op) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) case BPF_SOCK_OPS_RWND_INIT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) rv = rwnd_init;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) case BPF_SOCK_OPS_TCP_CONNECT_CB:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) /* Set sndbuf and rcvbuf of active connections */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) sizeof(bufsize));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) &bufsize, sizeof(bufsize));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) sizeof(iw));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) /* Set sndbuf and rcvbuf of passive connections */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) sizeof(bufsize));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) &bufsize, sizeof(bufsize));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) rv = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) #ifdef DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) bpf_printk("Returning %d\n", rv);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) skops->reply = rv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) char _license[] SEC("license") = "GPL";