Re: [Qemu-devel] [PATCH v4 4/4] Add support for net bridge

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

On 11/02/2011 04:12 AM, Mark Wu wrote:
> On 11/02/2011 01:13 AM, Corey Bryant wrote:
>> static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
>> {
>> int fd, vnet_hdr_required;
>> @@ -433,8 +570,11 @@ int net_init_tap(QemuOpts *opts, Monitor *mon,
>> const char *name, VLANState *vlan
>> if (qemu_opt_get(opts, "ifname") ||
>> qemu_opt_get(opts, "script") ||
>> qemu_opt_get(opts, "downscript") ||
>> - qemu_opt_get(opts, "vnet_hdr")) {
>> - error_report("ifname=, script=, downscript= and vnet_hdr= is invalid
>> with fd=");
>> + qemu_opt_get(opts, "vnet_hdr") ||
>> + qemu_opt_get(opts, "br") ||
>> + qemu_opt_get(opts, "helper")) {
>> + error_report("ifname=, script=, downscript=, vnet_hdr=,"
>> + "br= and helper= are invalid with fd=");
>> return -1;
>> }
> If
>> @@ -446,7 +586,40 @@ int net_init_tap(QemuOpts *opts, Monitor *mon,
>> const char *name, VLANState *vlan
>> fcntl(fd, F_SETFL, O_NONBLOCK);
>>
>> vnet_hdr = tap_probe_vnet_hdr(fd);
>> + } else if (qemu_opt_get(opts, "helper")) {
>> + if (qemu_opt_get(opts, "ifname") ||
>> + qemu_opt_get(opts, "script") ||
>> + qemu_opt_get(opts, "downscript")) {
>> + error_report("ifname=, script= and downscript="
>> + "are invalid with helper=");
>> + return -1;
>> + }
>> +
>> + if (!qemu_opt_get(opts, "br")) {
>> + qemu_opt_set(opts, "br", DEFAULT_BRIDGE_INTERFACE);
>> + }
>> +
>> + fd = net_bridge_run_helper(qemu_opt_get(opts, "helper"),
>> + qemu_opt_get(opts, "br"));
>> + if (fd == -1) {
>> + return -1;
>> + }
>> +
>> + fcntl(fd, F_SETFL, O_NONBLOCK);
>> +
>> + vnet_hdr = tap_probe_vnet_hdr(fd);
>> +
>> + s = net_tap_fd_init(vlan, "bridge", name, fd, vnet_hdr);
>>
> The helper run with "--use-vnet" by default, so the option "vnet_hdr"
> will not be honored. We can make "vnet_hdr" invalid with "br" or check
> the option "vnet_hdr" in function net_bridge_run_helper.
>

Good point.  It seems like we should honor the "vnet_hdr" option rather 
than make it invalid for a network helper.

-- 
Regards,
Corey