cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

bpf_iter_setsockopt.c (1551B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2021 Facebook */
      3#include "bpf_iter.h"
      4#include "bpf_tracing_net.h"
      5#include <bpf/bpf_helpers.h>
      6#include <bpf/bpf_endian.h>
      7
      8#define bpf_tcp_sk(skc)	({				\
      9	struct sock_common *_skc = skc;			\
     10	sk = NULL;					\
     11	tp = NULL;					\
     12	if (_skc) {					\
     13		tp = bpf_skc_to_tcp_sock(_skc);		\
     14		sk = (struct sock *)tp;			\
     15	}						\
     16	tp;						\
     17})
     18
     19unsigned short reuse_listen_hport = 0;
     20unsigned short listen_hport = 0;
     21char cubic_cc[TCP_CA_NAME_MAX] = "bpf_cubic";
     22char dctcp_cc[TCP_CA_NAME_MAX] = "bpf_dctcp";
     23bool random_retry = false;
     24
     25static bool tcp_cc_eq(const char *a, const char *b)
     26{
     27	int i;
     28
     29	for (i = 0; i < TCP_CA_NAME_MAX; i++) {
     30		if (a[i] != b[i])
     31			return false;
     32		if (!a[i])
     33			break;
     34	}
     35
     36	return true;
     37}
     38
     39SEC("iter/tcp")
     40int change_tcp_cc(struct bpf_iter__tcp *ctx)
     41{
     42	char cur_cc[TCP_CA_NAME_MAX];
     43	struct tcp_sock *tp;
     44	struct sock *sk;
     45	int ret;
     46
     47	if (!bpf_tcp_sk(ctx->sk_common))
     48		return 0;
     49
     50	if (sk->sk_family != AF_INET6 ||
     51	    (sk->sk_state != TCP_LISTEN &&
     52	     sk->sk_state != TCP_ESTABLISHED) ||
     53	    (sk->sk_num != reuse_listen_hport &&
     54	     sk->sk_num != listen_hport &&
     55	     bpf_ntohs(sk->sk_dport) != listen_hport))
     56		return 0;
     57
     58	if (bpf_getsockopt(tp, SOL_TCP, TCP_CONGESTION,
     59			   cur_cc, sizeof(cur_cc)))
     60		return 0;
     61
     62	if (!tcp_cc_eq(cur_cc, cubic_cc))
     63		return 0;
     64
     65	if (random_retry && bpf_get_prandom_u32() % 4 == 1)
     66		return 1;
     67
     68	bpf_setsockopt(tp, SOL_TCP, TCP_CONGESTION, dctcp_cc, sizeof(dctcp_cc));
     69	return 0;
     70}
     71
     72char _license[] SEC("license") = "GPL";