Eric Lee / smarc-fsl-linux-kernel

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samples/bpf/tcp_bufs_kern.c 2.12 KB
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d9925368a   Lawrence Brakmo   bpf: Sample BPF p... 
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  /* 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 initial receive window to 40 packets and send
   * and receive buffers to 1.5MB. This would usually be done after
   * doing appropriate checks that indicate the hosts are far enough
   * away (i.e. large RTT).
   *
ea9b63620   Jakub Kicinski   samples: bpf: rem... 
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   * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
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   */
  
  #include <uapi/linux/bpf.h>
  #include <uapi/linux/if_ether.h>
  #include <uapi/linux/if_packet.h>
  #include <uapi/linux/ip.h>
  #include <linux/socket.h>
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  #include <bpf/bpf_helpers.h>
  #include <bpf/bpf_endian.h>
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  #define DEBUG 1
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  SEC("sockops")
  int bpf_bufs(struct bpf_sock_ops *skops)
  {
  	int bufsize = 1500000;
  	int rwnd_init = 40;
  	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 &&
a4174f056   Lawrence Brakmo   bpf: Fix tcp_bufs... 
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  	    skops->local_port != 55601) {
  		skops->reply = -1;
  		return 1;
  	}
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  	op = (int) skops->op;
  
  #ifdef DEBUG
  	bpf_printk("Returning %d
  ", rv);
  #endif
  
  	/* Usually there would be a check to insure the hosts are far
  	 * from each other so it makes sense to increase buffer sizes
  	 */
  	switch (op) {
  	case BPF_SOCK_OPS_RWND_INIT:
  		rv = rwnd_init;
  		break;
  	case BPF_SOCK_OPS_TCP_CONNECT_CB:
  		/* Set sndbuf and rcvbuf of active connections */
  		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
  				    sizeof(bufsize));
a4174f056   Lawrence Brakmo   bpf: Fix tcp_bufs... 
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  		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
  				     &bufsize, sizeof(bufsize));
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  		break;
  	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
  		/* Nothing to do */
  		break;
  	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
  		/* Set sndbuf and rcvbuf of passive connections */
  		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
  				    sizeof(bufsize));
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  		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
  				     &bufsize, sizeof(bufsize));
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  		break;
  	default:
  		rv = -1;
  	}
  #ifdef DEBUG
  	bpf_printk("Returning %d
  ", rv);
  #endif
  	skops->reply = rv;
  	return 1;
  }
  char _license[] SEC("license") = "GPL";