Hi, Long interface names like this may look like an obscure corner case, but they have become less obscure with systemd's network features, especially the NamePolicy=mac feature (see systemd.link(5)) which should cause ethernet interfaces to be renamed to something like enx00112233445566.
On Linux, isc-dhcp (not only the client) uses the SOCK_PACKET inteface with the sockaddr_pkt structure. (net/if_packet.h) to send "raw" packets. sockaddr_pkt.spkt_device[] has room for only 14 characters. This includes the terminating \0 character, leaving us with 13 useable characters. The reason for all this is use of that deprecated interface. isc-dhcp could use the AF_PACKET introduced with Linux 2.2 instead (as suggested in a comment in if_packet.h). In that case, the interface name is irrelevant when sending a packet, only the ifindex is used -- and it's possible to look that up using interface names of up to 15 characters. (Which is already done in get_hw_addr.) Cheers, -Hilko -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
