bpf: Support for setting initial receive window
This patch adds suppport for setting the initial advertized window from within a BPF_SOCK_OPS program. This can be used to support larger initial cwnd values in environments where it is known to be safe. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
committed by
David S. Miller
parent
61bc4d8daa
commit
13d3b1ebe2
@@ -351,6 +351,7 @@ void tcp_openreq_init_rwin(struct request_sock *req,
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int full_space = tcp_full_space(sk_listener);
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u32 window_clamp;
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__u8 rcv_wscale;
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u32 rcv_wnd;
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int mss;
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mss = tcp_mss_clamp(tp, dst_metric_advmss(dst));
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@@ -363,6 +364,12 @@ void tcp_openreq_init_rwin(struct request_sock *req,
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(req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0))
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req->rsk_window_clamp = full_space;
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rcv_wnd = tcp_rwnd_init_bpf((struct sock *)req);
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if (rcv_wnd == 0)
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rcv_wnd = dst_metric(dst, RTAX_INITRWND);
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else if (full_space < rcv_wnd * mss)
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full_space = rcv_wnd * mss;
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/* tcp_full_space because it is guaranteed to be the first packet */
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tcp_select_initial_window(full_space,
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mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0),
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@@ -370,7 +377,7 @@ void tcp_openreq_init_rwin(struct request_sock *req,
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&req->rsk_window_clamp,
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ireq->wscale_ok,
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&rcv_wscale,
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dst_metric(dst, RTAX_INITRWND));
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rcv_wnd);
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ireq->rcv_wscale = rcv_wscale;
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}
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EXPORT_SYMBOL(tcp_openreq_init_rwin);
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