qemu-command: use -net socket, fd= with slirp-helper

If a slirp-helper is associated with a network interface (after
probing & preparing succesfully), pass the socket fd to QEMU and use
"-net socket,fd=".
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_command.c

@@ -28,6 +28,7 @@
 #include "qemu_alias.h"
 #include "qemu_security.h"
 #include "qemu_dbus.h"
+#include "qemu_slirp.h"
 #include "qemu_block.h"
 #include "cpu/cpu.h"
 #include "dirname.h"
@@ -3909,7 +3910,8 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
                     char **tapfd,
                     size_t tapfdSize,
                     char **vhostfd,
-                    size_t vhostfdSize)
+                    size_t vhostfdSize,
+                    const char *slirpfd)
 {
     bool is_tap = false;
     VIR_AUTOCLEAN(virBuffer) buf = VIR_BUFFER_INITIALIZER;
@@ -3979,24 +3981,28 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
         break;
 
     case VIR_DOMAIN_NET_TYPE_USER:
-        virBufferAddLit(&buf, "user,");
-        for (i = 0; i < net->guestIP.nips; i++) {
-            const virNetDevIPAddr *ip = net->guestIP.ips[i];
-            VIR_AUTOFREE(char *) addr = NULL;
-            const char *prefix = "";
-
-            if (!(addr = virSocketAddrFormat(&ip->address)))
-                goto cleanup;
-
-            if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET))
-                prefix = "net=";
-            if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6))
-                prefix = "ipv6-net=";
-
-            virBufferAsprintf(&buf, "%s%s", prefix, addr);
-            if (ip->prefix)
-                virBufferAsprintf(&buf, "/%u", ip->prefix);
-            virBufferAddChar(&buf, ',');
+        if (slirpfd) {
+            virBufferAsprintf(&buf, "socket,fd=%s,", slirpfd);
+        } else {
+            virBufferAddLit(&buf, "user,");
+            for (i = 0; i < net->guestIP.nips; i++) {
+                const virNetDevIPAddr *ip = net->guestIP.ips[i];
+                VIR_AUTOFREE(char *) addr = NULL;
+                const char *prefix = "";
+
+                if (!(addr = virSocketAddrFormat(&ip->address)))
+                    goto cleanup;
+
+                if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET))
+                    prefix = "net=";
+                if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6))
+                    prefix = "ipv6-net=";
+
+                virBufferAsprintf(&buf, "%s%s", prefix, addr);
+                if (ip->prefix)
+                    virBufferAsprintf(&buf, "/%u", ip->prefix);
+                virBufferAddChar(&buf, ',');
+            }
         }
         break;
 
@@ -8312,10 +8318,10 @@ qemuInterfaceVhostuserConnect(virQEMUDriverPtr driver,
 
 static int
 qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
+                              virDomainObjPtr vm,
                               virLogManagerPtr logManager,
                               virSecurityManagerPtr secManager,
                               virCommandPtr cmd,
-                              virDomainDefPtr def,
                               virDomainNetDefPtr net,
                               virQEMUCapsPtr qemuCaps,
                               unsigned int bootindex,
@@ -8324,6 +8330,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
                               size_t *nnicindexes,
                               int **nicindexes)
 {
+    virDomainDefPtr def = vm->def;
     int ret = -1;
     VIR_AUTOFREE(char *) nic = NULL;
     VIR_AUTOFREE(char *) host = NULL;
@@ -8334,9 +8341,11 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
     size_t vhostfdSize = 0;
     char **tapfdName = NULL;
     char **vhostfdName = NULL;
+    VIR_AUTOFREE(char *) slirpfdName = NULL;
     virDomainNetType actualType = virDomainNetGetActualType(net);
     virNetDevBandwidthPtr actualBandwidth;
     bool requireNicdev = false;
+    qemuSlirpPtr slirp;
     size_t i;
 
 
@@ -8562,6 +8571,16 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
             goto cleanup;
     }
 
+    slirp = QEMU_DOMAIN_NETWORK_PRIVATE(net)->slirp;
+    if (slirp && !standalone) {
+        int slirpfd = qemuSlirpGetFD(slirp);
+        virCommandPassFD(cmd, slirpfd,
+                         VIR_COMMAND_PASS_FD_CLOSE_PARENT);
+        if (virAsprintf(&slirpfdName, "%d", slirpfd) < 0)
+            goto cleanup;
+    }
+
+
     for (i = 0; i < tapfdSize; i++) {
         if (qemuSecuritySetTapFDLabel(driver->securityManager,
                                       def, tapfd[i]) < 0)
@@ -8586,7 +8605,8 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
 
     if (!(host = qemuBuildHostNetStr(net, driver,
                                      tapfdName, tapfdSize,
-                                     vhostfdName, vhostfdSize)))
+                                     vhostfdName, vhostfdSize,
+                                     slirpfdName)))
         goto cleanup;
     virCommandAddArgList(cmd, "-netdev", host, NULL);
 
@@ -8651,10 +8671,10 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
  */
 static int
 qemuBuildNetCommandLine(virQEMUDriverPtr driver,
+                        virDomainObjPtr vm,
                         virLogManagerPtr logManager,
                         virSecurityManagerPtr secManager,
                         virCommandPtr cmd,
-                        virDomainDefPtr def,
                         virQEMUCapsPtr qemuCaps,
                         virNetDevVPortProfileOp vmop,
                         bool standalone,
@@ -8665,6 +8685,7 @@ qemuBuildNetCommandLine(virQEMUDriverPtr driver,
     size_t i;
     int last_good_net = -1;
     virErrorPtr originalError = NULL;
+    virDomainDefPtr def = vm->def;
 
     if (def->nnets) {
         unsigned int bootNet = 0;
@@ -8680,7 +8701,7 @@ qemuBuildNetCommandLine(virQEMUDriverPtr driver,
         for (i = 0; i < def->nnets; i++) {
             virDomainNetDefPtr net = def->nets[i];
 
-            if (qemuBuildInterfaceCommandLine(driver, logManager, secManager, cmd, def, net,
+            if (qemuBuildInterfaceCommandLine(driver, vm, logManager, secManager, cmd, net,
                                               qemuCaps, bootNet, vmop,
                                               standalone, nnicindexes,
                                               nicindexes) < 0)
@@ -10402,7 +10423,7 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildFilesystemCommandLine(cmd, def, qemuCaps) < 0)
         return NULL;
 
-    if (qemuBuildNetCommandLine(driver, logManager, secManager, cmd, def,
+    if (qemuBuildNetCommandLine(driver, vm, logManager, secManager, cmd,
                                 qemuCaps, vmop, standalone,
                                 nnicindexes, nicindexes, &bootHostdevNet) < 0)
         return NULL;

src/qemu/qemu_command.h

@@ -90,7 +90,8 @@ char *qemuBuildHostNetStr(virDomainNetDefPtr net,
                           char **tapfd,
                           size_t tapfdSize,
                           char **vhostfd,
-                          size_t vhostfdSize);
+                          size_t vhostfdSize,
+                          const char *slirpfd);
 
 /* Current, best practice */
 char *qemuBuildNicDevStr(virDomainDefPtr def,

src/qemu/qemu_hotplug.c

@@ -1385,7 +1385,8 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
 
     if (!(netstr = qemuBuildHostNetStr(net, driver,
                                        tapfdName, tapfdSize,
-                                       vhostfdName, vhostfdSize)))
+                                       vhostfdName, vhostfdSize,
+                                       NULL)))
         goto cleanup;
 
     qemuDomainObjEnterMonitor(driver, vm);