Hi, I've modified the qemu source to add support for specifying a ifname
when using -netdev tap or -netdev bridge with a helper. Currently this
is not supported and all interface names are named tap0, tap1, ...
Hopfully i'm submitting this correctly, if not I appologize. Also, my C
is a bit rusty... well it was never great to begin with :)
--
Shaun Reitan
NDCHost.com
From 9af8c88781d63637822c6edea1f83e98199a570b Mon Sep 17 00:00:00 2001
From: Shaun Reitan <shaun.rei...@ndchost.com>
Date: Mon, 15 Jan 2018 17:40:38 -0800
Subject: [PATCH 1/4] Add support for setting a TAP interface name
Signed-off-by: Shaun Reitan <shaun.rei...@ndchost.com>
---
qemu-bridge-helper.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index 5396fbf..7b01cd5 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -57,7 +57,7 @@ typedef QSIMPLEQ_HEAD(ACLList, ACLRule) ACLList;
static void usage(void)
{
fprintf(stderr,
- "Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd\n");
+ "Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd
[--ifname=name]\n");
}
static int parse_acl_file(const char *filename, ACLList *acl_list)
@@ -223,6 +223,7 @@ int main(int argc, char **argv)
int use_vnet = 0;
int mtu;
const char *bridge = NULL;
+ const char *ifname = NULL;
char iface[IFNAMSIZ];
int index;
ACLRule *acl_rule;
@@ -249,6 +250,8 @@ int main(int argc, char **argv)
bridge = &argv[index][5];
} else if (strncmp(argv[index], "--fd=", 5) == 0) {
unixfd = atoi(&argv[index][5]);
+ } else if (strncmp(argv[index], "--ifname=", 9) == 0) {
+ ifname = &argv[index][9];
} else {
usage();
return EXIT_FAILURE;
@@ -320,7 +323,11 @@ int main(int argc, char **argv)
/* request a tap device, disable PI, and add vnet header support if
* requested and it's available. */
- prep_ifreq(&ifr, "tap%d");
+ if (ifname == NULL) {
+ prep_ifreq(&ifr, "tap%d");
+ } else {
+ prep_ifreq(&ifr, ifname);
+ }
ifr.ifr_flags = IFF_TAP|IFF_NO_PI;
if (use_vnet && has_vnet_hdr(fd)) {
ifr.ifr_flags |= IFF_VNET_HDR;
--
2.9.5
From 35a24821d437d1955c00dc64f7cd82d24e31ecda Mon Sep 17 00:00:00 2001
From: Shaun Reitan <shaun.rei...@ndchost.com>
Date: Mon, 15 Jan 2018 17:42:32 -0800
Subject: [PATCH 2/4] Add ifname to NetdevBridgeOptions
Signed-off-by: Shaun Reitan <shaun.rei...@ndchost.com>
---
qapi/net.json | 1 +
1 file changed, 1 insertion(+)
diff --git a/qapi/net.json b/qapi/net.json
index 4beff5d..5b5b281 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -402,6 +402,7 @@
{ 'struct': 'NetdevBridgeOptions',
'data': {
'*br': 'str',
+ '*ifname': 'str',
'*helper': 'str' } }
##
--
2.9.5
From 92bbc897a04628358e6d698d70c5a257a912b67c Mon Sep 17 00:00:00 2001
From: Shaun Reitan <shaun.rei...@ndchost.com>
Date: Mon, 15 Jan 2018 17:43:24 -0800
Subject: [PATCH 3/4] Add ifname support to -netdev bridge options
Signed-off-by: Shaun Reitan <shaun.rei...@ndchost.com>
---
qemu-options.hx | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/qemu-options.hx b/qemu-options.hx
index 678181c..81cbc3c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1961,7 +1961,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
" use 'queues=n' to specify the number of queues to be created for
multiqueue TAP\n"
" use 'poll-us=n' to speciy the maximum number of microseconds that
could be\n"
" spent on busy polling for vhost net\n"
- "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
+ "-netdev bridge,id=str[,br=bridge][,helper=helper][,ifname=name]\n"
" configure a host TAP network backend with ID 'str' that is\n"
" connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
" using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
--
2.9.5
From 797ca0174430ffd0dc8c5a36ce86380816ff2eee Mon Sep 17 00:00:00 2001
From: Shaun Reitan <shaun.rei...@ndchost.com>
Date: Mon, 15 Jan 2018 17:43:42 -0800
Subject: [PATCH 4/4] Add ability to set ifname when using -netdev bridge
and
-netdev tap when using a helper
Signed-off-by: Shaun Reitan <shaun.rei...@ndchost.com>
---
net/tap.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
diff --git a/net/tap.c b/net/tap.c
index 979e622..1180094 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -472,7 +472,7 @@ static int recv_fd(int c)
}
static int net_bridge_run_helper(const char *helper, const char
*bridge,
- Error **errp)
+ const char *ifname, Error **errp)
{
sigset_t oldmask, mask;
int pid, status;
@@ -499,7 +499,8 @@ static int net_bridge_run_helper(const char *helper,
const char *bridge,
int open_max = sysconf(_SC_OPEN_MAX), i;
char fd_buf[6+10];
char br_buf[6+IFNAMSIZ] = {0};
- char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
+ char ifname_buf[10+IFNAMSIZ];
+ char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) +
sizeof(ifname_buf) + 15];
for (i = 3; i < open_max; i++) {
if (i != sv[1]) {
@@ -516,8 +517,12 @@ static int net_bridge_run_helper(const char
*helper, const char *bridge,
snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=",
bridge);
}
- snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
- helper, "--use-vnet", fd_buf, br_buf);
+ if (strstr(helper, "--ifname=") == NULL && ifname != NULL) {
+ snprintf(ifname_buf, sizeof(ifname_buf), "%s%s", "--ifname=", ifname);
+ }
+
+ snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s %s",
+ helper, "--use-vnet", fd_buf, br_buf, ifname_buf);
parg = args;
*parg++ = (char *)"sh";
@@ -536,6 +541,12 @@ static int net_bridge_run_helper(const char
*helper, const char *bridge,
*parg++ = (char *)"--use-vnet";
*parg++ = fd_buf;
*parg++ = br_buf;
+
+ if (ifname != NULL) {
+ snprintf(ifname_buf, sizeof(ifname_buf), "%s%s", "--ifname=", ifname);
+ *parg++ = ifname_buf;
+ }
+
*parg++ = NULL;
execv(helper, args);
@@ -586,7 +597,7 @@ int net_init_bridge(const Netdev *netdev, const char
*name,
helper = bridge->has_helper ? bridge->helper :
DEFAULT_BRIDGE_HELPER;
br = bridge->has_br ? bridge->br : DEFAULT_BRIDGE_INTERFACE;
- fd = net_bridge_run_helper(helper, br, errp);
+ fd = net_bridge_run_helper(helper, br, bridge->ifname, errp);
if (fd == -1) {
return -1;
}
@@ -854,16 +865,17 @@ free_fail:
g_free(vhost_fds);
return -1;
} else if (tap->has_helper) {
- if (tap->has_ifname || tap->has_script || tap->has_downscript ||
- tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
- error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
- "queues=, and vhostfds= are invalid with helper=");
+ if (tap->has_script || tap->has_downscript || tap->has_vnet_hdr ||
+ tap->has_queues || tap->has_vhostfds) {
+ error_setg(errp, "script=, downscript=, vnet_hdr=, queues=, and "
+ "vhostfds= are invalid with helper=");
return -1;
}
fd = net_bridge_run_helper(tap->helper,
tap->has_br ?
tap->br : DEFAULT_BRIDGE_INTERFACE,
+ tap->ifname,
errp);
if (fd == -1) {
return -1;
--
2.9.5
