From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756479AbdJJRTd (ORCPT ); Tue, 10 Oct 2017 13:19:33 -0400 Received: from mail-pf0-f177.google.com ([209.85.192.177]:53494 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756353AbdJJRTa (ORCPT ); Tue, 10 Oct 2017 13:19:30 -0400 X-Google-Smtp-Source: AOwi7QBeidfUrQIcHYl2VtAYN3MbrC1uipk1C1I2vV3YrQMCE0GaVuOCnIvXPM1LhxMZsANcCfiseA== Date: Tue, 10 Oct 2017 10:19:21 -0700 From: Stephen Hemminger To: Christina Jacob Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, brouer@redhat.com, Sunil.Goutham@cavium.com, daniel@iogearbox.net, dsahern@gmail.com, Christina Jacob Subject: Re: [PATCH v2] xdp: Sample xdp program implementing ip forward Message-ID: <20171010101921.30136d48@shemminger-XPS-13-9360> In-Reply-To: <1507620532-25804-2-git-send-email-Christina.Jacob@cavium.com> References: <1507620532-25804-1-git-send-email-Christina.Jacob@cavium.com> <1507620532-25804-2-git-send-email-Christina.Jacob@cavium.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Oct 2017 12:58:52 +0530 Christina Jacob wrote: > +/* Get the mac address of the interface given interface name */ > +static long *getmac(char *iface) > +{ > + int fd; > + struct ifreq ifr; > + long *mac = NULL; > + > + fd = socket(AF_INET, SOCK_DGRAM, 0); > + ifr.ifr_addr.sa_family = AF_INET; > + strncpy(ifr.ifr_name, iface, IFNAMSIZ - 1); > + ioctl(fd, SIOCGIFHWADDR, &ifr); > + mac = (long *)ifr.ifr_hwaddr.sa_data; > + close(fd); > + return mac; Always check return value of ioctl. You are assuming sizeof(long) > 6 bytes. Also the byte order.