tcpdump mailing list archives
Re: Devices and adresses in libpcap
From: Guy Harris <guy () alum mit edu>
Date: Sat, 12 Apr 2008 14:05:15 -0700
David Rosal wrote:
As far as I know, each network interface (for example eth0), can have different adresses, because in pcap_findalldevs(), a pcap_if_t does not hold a single pcap_addr_t but a linked list of all addresses for each interface/device.
Yes, it can have multiple addresses, and, yes, pcap_findalldevs() returns all of the ones it can get.
But pcap_lookupnet() only returns one address for a given device.
Yes, it returns only one address.
So the question is: If pcap_lookupnet() only returns one address (and its netmask), does it mean that it discards all the other addresses for that device?
Yes, it discards any other addresses for the interface. On UN*X, it returns the IP address and mask you get from an SIOCGIFADDR and SIOCGIFNETMASK ioctl, which is probably the first of the IP addresses; on Windows, it gets the entire set of address/mask pairs and returns only the first one.
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Current thread:
- Devices and adresses in libpcap David Rosal (Apr 12)
- Re: Devices and adresses in libpcap Guy Harris (Apr 12)
- Re: Devices and adresses in libpcap David Rosal (Apr 13)
- Re: Devices and adresses in libpcap Giovanni Venturi (Apr 13)
- Re: Devices and adresses in libpcap David Rosal (Apr 13)
- Re: Devices and adresses in libpcap Guy Harris (Apr 13)
- Re: Devices and adresses in libpcap David Rosal (Apr 13)
- Re: Devices and adresses in libpcap Eloy Paris (Apr 14)
- Re: Devices and adresses in libpcap David Rosal (Apr 13)
- Re: Devices and adresses in libpcap Guy Harris (Apr 12)