From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Paasch Subject: [RFC 01/14] tcp: Write options after the header has been fully done Date: Mon, 18 Dec 2017 13:50:56 -0800 Message-ID: <20171218215109.38700-2-cpaasch@apple.com> References: <20171218215109.38700-1-cpaasch@apple.com> Content-Transfer-Encoding: 7BIT Cc: Eric Dumazet , Mat Martineau , Alexei Starovoitov To: netdev@vger.kernel.org Return-path: Received: from mail-out6.apple.com ([17.151.62.28]:48858 "EHLO mail-in6.apple.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935637AbdLRVva (ORCPT ); Mon, 18 Dec 2017 16:51:30 -0500 In-reply-to: <20171218215109.38700-1-cpaasch@apple.com> Sender: netdev-owner@vger.kernel.org List-ID: The generic TCP-option framework will need to have access to the full TCP-header (e.g., if we want to compute a checksum for TCP-MD5). Thus, we move the call to tcp_options_write() to after all the fields in the header have been filled out. Signed-off-by: Christoph Paasch Reviewed-by: Mat Martineau --- net/ipv4/tcp_output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 04be9f833927..0f66d101d0ca 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1126,7 +1126,6 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, } } - tcp_options_write((__be32 *)(th + 1), tp, &opts); skb_shinfo(skb)->gso_type = sk->sk_gso_type; if (likely(!(tcb->tcp_flags & TCPHDR_SYN))) { th->window = htons(tcp_select_window(sk)); @@ -1137,6 +1136,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, */ th->window = htons(min(tp->rcv_wnd, 65535U)); } + tcp_options_write((__be32 *)(th + 1), tp, &opts); #ifdef CONFIG_TCP_MD5SIG /* Calculate the MD5 hash, as we have all we need now */ if (md5) { @@ -3242,8 +3242,8 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */ th->window = htons(min(req->rsk_rcv_wnd, 65535U)); - tcp_options_write((__be32 *)(th + 1), NULL, &opts); th->doff = (tcp_header_size >> 2); + tcp_options_write((__be32 *)(th + 1), NULL, &opts); __TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS); #ifdef CONFIG_TCP_MD5SIG -- 2.15.0