17bc62e28SLawrence Brakmo /* Copyright (c) 2017 Facebook
27bc62e28SLawrence Brakmo *
37bc62e28SLawrence Brakmo * This program is free software; you can redistribute it and/or
47bc62e28SLawrence Brakmo * modify it under the terms of version 2 of the GNU General Public
57bc62e28SLawrence Brakmo * License as published by the Free Software Foundation.
67bc62e28SLawrence Brakmo *
77bc62e28SLawrence Brakmo * BPF program to set initial congestion window and initial receive
87bc62e28SLawrence Brakmo * window to 40 packets and send and receive buffers to 1.5MB. This
97bc62e28SLawrence Brakmo * would usually be done after doing appropriate checks that indicate
107bc62e28SLawrence Brakmo * the hosts are far enough away (i.e. large RTT).
117bc62e28SLawrence Brakmo *
12ea9b6362SJakub Kicinski * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
137bc62e28SLawrence Brakmo */
147bc62e28SLawrence Brakmo
157bc62e28SLawrence Brakmo #include <uapi/linux/bpf.h>
167bc62e28SLawrence Brakmo #include <uapi/linux/if_ether.h>
177bc62e28SLawrence Brakmo #include <uapi/linux/if_packet.h>
187bc62e28SLawrence Brakmo #include <uapi/linux/ip.h>
197bc62e28SLawrence Brakmo #include <linux/socket.h>
20*7cf245a3SToke Høiland-Jørgensen #include <bpf/bpf_helpers.h>
21*7cf245a3SToke Høiland-Jørgensen #include <bpf/bpf_endian.h>
227bc62e28SLawrence Brakmo
237bc62e28SLawrence Brakmo #define DEBUG 1
247bc62e28SLawrence Brakmo
257bc62e28SLawrence Brakmo SEC("sockops")
bpf_iw(struct bpf_sock_ops * skops)267bc62e28SLawrence Brakmo int bpf_iw(struct bpf_sock_ops *skops)
277bc62e28SLawrence Brakmo {
287bc62e28SLawrence Brakmo int bufsize = 1500000;
297bc62e28SLawrence Brakmo int rwnd_init = 40;
307bc62e28SLawrence Brakmo int iw = 40;
317bc62e28SLawrence Brakmo int rv = 0;
327bc62e28SLawrence Brakmo int op;
337bc62e28SLawrence Brakmo
347bc62e28SLawrence Brakmo /* For testing purposes, only execute rest of BPF program
357bc62e28SLawrence Brakmo * if neither port numberis 55601
367bc62e28SLawrence Brakmo */
377bc62e28SLawrence Brakmo if (bpf_ntohl(skops->remote_port) != 55601 &&
38e1853319SLawrence Brakmo skops->local_port != 55601) {
39e1853319SLawrence Brakmo skops->reply = -1;
40e1853319SLawrence Brakmo return 1;
41e1853319SLawrence Brakmo }
427bc62e28SLawrence Brakmo
437bc62e28SLawrence Brakmo op = (int) skops->op;
447bc62e28SLawrence Brakmo
457bc62e28SLawrence Brakmo #ifdef DEBUG
467bc62e28SLawrence Brakmo bpf_printk("BPF command: %d\n", op);
477bc62e28SLawrence Brakmo #endif
487bc62e28SLawrence Brakmo
497bc62e28SLawrence Brakmo /* Usually there would be a check to insure the hosts are far
507bc62e28SLawrence Brakmo * from each other so it makes sense to increase buffer sizes
517bc62e28SLawrence Brakmo */
527bc62e28SLawrence Brakmo switch (op) {
537bc62e28SLawrence Brakmo case BPF_SOCK_OPS_RWND_INIT:
547bc62e28SLawrence Brakmo rv = rwnd_init;
557bc62e28SLawrence Brakmo break;
567bc62e28SLawrence Brakmo case BPF_SOCK_OPS_TCP_CONNECT_CB:
577bc62e28SLawrence Brakmo /* Set sndbuf and rcvbuf of active connections */
587bc62e28SLawrence Brakmo rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
597bc62e28SLawrence Brakmo sizeof(bufsize));
60e1853319SLawrence Brakmo rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
617bc62e28SLawrence Brakmo &bufsize, sizeof(bufsize));
627bc62e28SLawrence Brakmo break;
637bc62e28SLawrence Brakmo case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
647bc62e28SLawrence Brakmo rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw,
657bc62e28SLawrence Brakmo sizeof(iw));
667bc62e28SLawrence Brakmo break;
677bc62e28SLawrence Brakmo case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
687bc62e28SLawrence Brakmo /* Set sndbuf and rcvbuf of passive connections */
697bc62e28SLawrence Brakmo rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
707bc62e28SLawrence Brakmo sizeof(bufsize));
71e1853319SLawrence Brakmo rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
727bc62e28SLawrence Brakmo &bufsize, sizeof(bufsize));
737bc62e28SLawrence Brakmo break;
747bc62e28SLawrence Brakmo default:
757bc62e28SLawrence Brakmo rv = -1;
767bc62e28SLawrence Brakmo }
777bc62e28SLawrence Brakmo #ifdef DEBUG
787bc62e28SLawrence Brakmo bpf_printk("Returning %d\n", rv);
797bc62e28SLawrence Brakmo #endif
807bc62e28SLawrence Brakmo skops->reply = rv;
817bc62e28SLawrence Brakmo return 1;
827bc62e28SLawrence Brakmo }
837bc62e28SLawrence Brakmo char _license[] SEC("license") = "GPL";
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