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[lwip-devel] [bug #61653] PPP Netmask Changed
From: |
Ashley Duncan |
Subject: |
[lwip-devel] [bug #61653] PPP Netmask Changed |
Date: |
Thu, 9 Dec 2021 17:37:23 -0500 (EST) |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36 |
URL:
<https://savannah.nongnu.org/bugs/?61653>
Summary: PPP Netmask Changed
Project: lwIP - A Lightweight TCP/IP stack
Submitted by: ashesman
Submitted on: Thu 09 Dec 2021 10:37:21 PM UTC
Category: PPP
Severity: 3 - Normal
Item Group: Faulty Behaviour
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Planned Release: None
lwIP version: 2.1.2
_______________________________________________________
Details:
Hi,
I am not sure if this is an issue, or my misunderstanding of PPP. Please
forgive me if it is the later...
I am using a PPPoS connection to a Ublox Nina W15 WiFi module. Has been
working great for years.
Today I tried to send UDP broadcast packets on the PPP netif. I calculate the
broadcast IP address by ORing the compliment of the netmask with the netif IP
address. I noticed that even though the PPP link is configured for netmask
255.255.255.0, once connected the netmask is changed to 255.255.255.255
(IPADDR_BROADCAST). this happens in get_mask, line 1232 of ppp.c.
The above calculation results in the broadcast address being calculated as the
netifs IP address. So any packets sent on that PPP netif are caught by
loopback and not actually sent on the PPP link.
I guess that a PPP link is always one to one so the concept of broadcast may
not exist on PPP? Although in most PPPoS cases, the PPP link is a conduit to
another network interface so should pass all traffic in both directions?
_______________________________________________________
Reply to this item at:
<https://savannah.nongnu.org/bugs/?61653>
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- [lwip-devel] [bug #61653] PPP Netmask Changed,
Ashley Duncan <=