From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark McLoughlin Subject: [PATCH] kvm: qemu: Handle tap fds with IFF_VNET_HDR Date: Wed, 20 Aug 2008 18:04:58 +0100 Message-ID: <1219251898.5068.33.camel@muff> References: <1218485535-877-1-git-send-email-markmc@redhat.com> <48A1957C.4070007@qumranet.com> <1218638393.29159.38.camel@muff> <48A30ABE.3040903@qumranet.com> Reply-To: Mark McLoughlin Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([66.187.233.31]:56033 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751839AbYHTRFZ (ORCPT ); Wed, 20 Aug 2008 13:05:25 -0400 In-Reply-To: <48A30ABE.3040903@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: Allow users to pass an IFF_VNET_HDR tap fd via "-net tap,fd=X" by querying the fd with the recently added TUNGETIFF ioctl() to see if IFF_VNET_HDR has been enabled. Note: users wishing to pass an IFF_VNET_HDR tap fd to qemu should check both that a) this version of qemu can handle such an fd and b) that the TUNGETIFF ioctl() is available in the running kernel. We add a comment to the "qemu -help" output to indicate to users that this version of qemu supports IFF_VNET_HDR. Signed-off-by: Mark McLoughlin --- qemu/vl.c | 21 ++++++++++++++++++++- 1 files changed, 20 insertions(+), 1 deletions(-) diff --git a/qemu/vl.c b/qemu/vl.c index 2dc1311..b9b202e 100644 --- a/qemu/vl.c +++ b/qemu/vl.c @@ -4536,6 +4536,22 @@ void tap_using_vnet_hdr(void *opaque, int using_vnet_hdr) s->using_vnet_hdr = using_vnet_hdr != 0; } +static int tap_probe_vnet_hdr(int fd) +{ +#if defined(TUNGETIFF) && defined(IFF_VNET_HDR) + struct ifreq ifr; + + if (ioctl(fd, TUNGETIFF, &ifr) != 0) { + fprintf(stderr, "TUNGETIFF ioctl() failed: %s\n", strerror(errno)); + return 0; + } + + return ifr.ifr_flags & IFF_VNET_HDR; +#else + return 0; +#endif +} + #ifdef TUNSETOFFLOAD static void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, int ecn) @@ -5501,7 +5517,7 @@ int net_client_init(const char *device, const char *p) fd = strtol(buf, NULL, 0); fcntl(fd, F_SETFL, O_NONBLOCK); ret = -1; - if (net_tap_fd_init(vlan, fd, 0)) + if (net_tap_fd_init(vlan, fd, tap_probe_vnet_hdr(fd))) ret = 0; } else { if (get_param_value(ifname, sizeof(ifname), "ifname", p) <= 0) { @@ -8319,6 +8335,9 @@ static void help(int exitcode) " and 'dfile' (default=%s);\n" " use '[down]script=no' to disable script execution;\n" " use 'fd=h' to connect to an already opened TAP interface\n" +#if defined(TUNGETIFF) && defined(IFF_VNET_HDR) + " 'h' may optinally be configured with the IFF_VNET_HDR flag\n" +#endif #endif "-net socket[,vlan=n][,fd=h][,listen=[host]:port][,connect=host:port]\n" " connect the vlan 'n' to another VLAN using a socket connection\n" -- 1.5.4.1