}
#if defined (CONFIG_BSD) || defined (__FreeBSD_kernel__)
-static int tap_open(char *ifname, int ifname_size, int *vnet_hdr)
+static int tap_open(char *ifname, int ifname_size,
+ int *vnet_hdr, int vnet_hdr_required)
{
int fd;
char *dev;
return tap_fd;
}
-static int tap_open(char *ifname, int ifname_size, int *vnet_hdr)
+static int tap_open(char *ifname, int ifname_size,
+ int *vnet_hdr, int vnet_hdr_required)
{
char dev[10]="";
int fd;
return fd;
}
#elif defined (_AIX)
-static int tap_open(char *ifname, int ifname_size, int *vnet_hdr)
+static int tap_open(char *ifname, int ifname_size,
+ int *vnet_hdr, int vnet_hdr_required)
{
fprintf (stderr, "no tap on AIX\n");
return -1;
}
#else
-static int tap_open(char *ifname, int ifname_size, int *vnet_hdr)
+static int tap_open(char *ifname, int ifname_size,
+ int *vnet_hdr, int vnet_hdr_required)
{
struct ifreq ifr;
int fd, ret;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
- {
+ if (*vnet_hdr) {
unsigned int features;
if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
*vnet_hdr = 1;
ifr.ifr_flags |= IFF_VNET_HDR;
}
+
+ if (vnet_hdr_required && !*vnet_hdr) {
+ qemu_error("vnet_hdr=1 requested, but no kernel "
+ "support for IFF_VNET_HDR available");
+ close(fd);
+ return -1;
+ }
}
if (ifname[0] != '\0')
static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
{
- int fd;
+ int fd, vnet_hdr_required;
char ifname[128] = {0,};
const char *setup_script;
pstrcpy(ifname, sizeof(ifname), qemu_opt_get(opts, "ifname"));
}
- *vnet_hdr = 0;
- TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr));
+ *vnet_hdr = qemu_opt_get_bool(opts, "vnet_hdr", 1);
+ if (qemu_opt_get(opts, "vnet_hdr")) {
+ vnet_hdr_required = *vnet_hdr;
+ } else {
+ vnet_hdr_required = 0;
+ }
+
+ TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr, vnet_hdr_required));
if (fd < 0) {
return -1;
}
if (qemu_opt_get(opts, "fd")) {
if (qemu_opt_get(opts, "ifname") ||
qemu_opt_get(opts, "script") ||
- qemu_opt_get(opts, "downscript")) {
- qemu_error("ifname=, script= and downscript= is invalid with fd=\n");
+ qemu_opt_get(opts, "downscript") ||
+ qemu_opt_get(opts, "vnet_hdr")) {
+ qemu_error("ifname=, script=, downscript= and vnet_hdr= is invalid with fd=\n");
return -1;
}
.name = "sndbuf",
.type = QEMU_OPT_SIZE,
.help = "send buffer limit"
+ }, {
+ .name = "vnet_hdr",
+ .type = QEMU_OPT_BOOL,
+ .help = "enable the IFF_VNET_HDR flag on the tap interface"
},
{ /* end of list */ }
},
"-net tap[,vlan=n][,name=str],ifname=name\n"
" connect the host TAP network interface to VLAN 'n'\n"
#else
- "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes]\n"
+ "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes][,vnet_hdr=on|off]\n"
" connect the host TAP network interface to VLAN 'n' and use the\n"
" network scripts 'file' (default=%s)\n"
" and 'dfile' (default=%s);\n"
" use 'fd=h' to connect to an already opened TAP interface\n"
" use 'sndbuf=nbytes' to limit the size of the send buffer; the\n"
" default of 'sndbuf=1048576' can be disabled using 'sndbuf=0'\n"
+ " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag; use\n"
+ " vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
#endif
"-net socket[,vlan=n][,name=str][,fd=h][,listen=[host]:port][,connect=host:port]\n"
" connect the vlan 'n' to another VLAN using a socket connection\n"