[RFI - fw3 zones] raw netdev semantics

Talk about Documentation
1

From [1]

device - List of raw network device names attached to this zone, e.g. ppp+ to match any PPP interface.

What I find confusing:

  • device vs. interface in the same sentence and appearing sort of conflicting
  • how can ppp+ be considered a raw device at all, e.g. considering [2] stipulating pppoe-$interface as interface but there is no pppoe-$device?

I would have thought that a raw netdev is a physical port, such as ethX or lanX, probably also radioX.

Thus appreciate to learn what counts as raw netdev and what defines it in the OpenWrt context/lingo.

[1] https://openwrt.org/docs/guide-user/firewall/firewall_configuration
[2] https://git.openwrt.org/?p=project%2Fnetifd.git&a=search&h=HEAD&st=grep&s=ppp

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I've noticed that these terms are not always consistent across pages. The network config page uses the terms "[OpenWrt] logical interface" and "physical interface":

Sections of the type interface declare logical networks serving as containers for IP address settings, aliases, routes, physical interface names and startfirewall_rules - they play a central role within the LEDE configuration concept.

~ https://openwrt.org/docs/guide-user/base-system/basic-networking#interfaces

From the Wiki page, "interface" clearly describes an OpenWrt-enumerated config defining one logical network. An interface can include multiple physical interfaces.

In your instance, I think "raw" should be replaced with "physical interface". Also note that network is commonly used in zone definitions (which lists the logical interfaces), not device (which lists the physical interfaces).

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And how does that jibe with

e.g. ppp+ to match any PPP interface.

?

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Iptables supports a special + placeholder syntax for -i and -o flags. ppp+ will match any Linux network device (the things you see in ifconfig or ip link) starting with ppp.

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source code[3] does not seem to define PPP+ as netdev and it would appear that nftables does not either.

[3] https://github.com/torvalds/linux/blob/master/include/linux/netdevice.h

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Well PPP+ isn't a netdev, it is a wildcard pattern matching things like ppp0, pppoe-wan, pppfoo etc. which are netdevs.

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