lwip-users
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lwip-users] TCP 2.0.2 pcb->snd_nxt is not updated somewhere?


From: Joel Cunningham
Subject: Re: [lwip-users] TCP 2.0.2 pcb->snd_nxt is not updated somewhere?
Date: Mon, 07 Aug 2017 09:32:14 -0500


On Aug 7, 2017, at 4:43 AM, Simonas Kazlauskas <address@hidden> wrote:

So it seems like for some reason the pcb->snd_nxt is one-off.

This seems really strange.  For an active open, sending of the SYN packet advances pcb->snd_nxt by 1.  See the following code in tcp_output():

snd_nxt = lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
  pcb->snd_nxt = snd_nxt;
}

In tcp_priv.h:

#define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))

Joel

reply via email to

[Prev in Thread] Current Thread [Next in Thread]