From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:41724) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rcj1Z-0000Kz-60 for qemu-devel@nongnu.org; Mon, 19 Dec 2011 14:37:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rcj1W-0000jr-KF for qemu-devel@nongnu.org; Mon, 19 Dec 2011 14:37:25 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:49709) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rcj1W-0000jC-7B for qemu-devel@nongnu.org; Mon, 19 Dec 2011 14:37:22 -0500 Received: from /spool/local by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 19 Dec 2011 12:37:17 -0700 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pBJJaKwr093466 for ; Mon, 19 Dec 2011 12:36:20 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pBJJaHni009808 for ; Mon, 19 Dec 2011 12:36:19 -0700 Message-ID: <4EEF922B.4050802@us.ibm.com> Date: Mon, 19 Dec 2011 13:36:11 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1324300318-3419-1-git-send-email-coreyb@linux.vnet.ibm.com> <1324300318-3419-5-git-send-email-coreyb@linux.vnet.ibm.com> In-Reply-To: <1324300318-3419-5-git-send-email-coreyb@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 4/4] Add support for net bridge List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Corey Bryant Cc: rmarwah@linux.vnet.ibm.com, qemu-devel@nongnu.org On 12/19/2011 07:11 AM, Corey Bryant wrote: > The most common use of -net tap is to connect a tap device to a bridge. This > requires the use of a script and running qemu as root in order to allocate a > tap device to pass to the script. > > This model is great for portability and flexibility but it's incredibly > difficult to eliminate the need to run qemu as root. The only really viable > mechanism is to use tunctl to create a tap device, attach it to a bridge as > root, and then hand that tap device to qemu. The problem with this mechanism > is that it requires administrator intervention whenever a user wants to create > a guest. > > By essentially writing a helper that implements the most common qemu-ifup > script that can be safely given cap_net_admin, we can dramatically simplify > things for non-privileged users. We still support existing -net tap options > as a mechanism for advanced users and backwards compatibility. > > Currently, this is very Linux centric but there's really no reason why it > couldn't be extended for other Unixes. > > A typical invocation would be similar to one of the following: > > qemu linux.img -net bridge -net nic,model=virtio > > qemu linux.img -net tap,helper=/usr/local/libexec/qemu-bridge-helper > -net nic,model=virtio > > qemu linux.img -netdev bridge,id=hn0 > -device virtio-net-pci,netdev=hn0,id=nic1 > > qemu linux.img -netdev tap,helper=/usr/local/libexec/qemu-bridge-helper,id=hn0 > -device virtio-net-pci,netdev=hn0,id=nic1 > > The default bridge that we attach to is br0. The thinking is that a distro > could preconfigure such an interface to allow out-of-the-box bridged networking. > > Alternatively, if a user wants to use a different bridge, a typical invocation > would be simliar to one of the following: > > qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio > > qemu linux.img -net tap,helper=/usr/local/libexec/qemu-bridge-helper,br=qemubr0 > -net nic,model=virtio > > qemu linux.img -netdev bridge,br=qemubr0,id=hn0 > -device virtio-net-pci,netdev=hn0,id=nic1 > > qemu linux.img -netdev tap,helper=/usr/local/libexec/qemu-bridge-helper,br=qemubr0,id=hn0 > -device virtio-net-pci,netdev=hn0,id=nic1 > > Signed-off-by: Anthony Liguori > Signed-off-by: Richa Marwaha > Signed-off-by: Corey Bryant > --- > configure | 2 + > net.c | 29 ++++++++- > net.h | 3 + > net/tap.c | 187 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > net/tap.h | 3 + > qemu-options.hx | 74 ++++++++++++++++++---- > 6 files changed, 281 insertions(+), 17 deletions(-) > > diff --git a/configure b/configure > index 6ed4196..4839694 100755 > --- a/configure > +++ b/configure > @@ -2905,6 +2905,8 @@ echo "sysconfdir=$sysconfdir">> $config_host_mak > echo "docdir=$docdir">> $config_host_mak > echo "confdir=$confdir">> $config_host_mak > echo "libexecdir=\${prefix}/libexec">> $config_host_mak > +echo "CONFIG_QEMU_SHAREDIR=\"$prefix$datasuffix\"">> $config_host_mak > +echo "CONFIG_QEMU_HELPERDIR=\"$prefix/libexec\"">> $config_host_mak > > case "$cpu" in > i386|x86_64|alpha|arm|cris|hppa|ia64|lm32|m68k|microblaze|mips|mips64|ppc|ppc64|s390|s390x|sparc|sparc64|unicore32) > diff --git a/net.c b/net.c > index f7bebf8..9296224 100644 > --- a/net.c > +++ b/net.c > @@ -952,6 +952,14 @@ static const struct { > .type = QEMU_OPT_STRING, > .help = "script to shut down the interface", > }, { > + .name = "br", > + .type = QEMU_OPT_STRING, > + .help = "bridge name", > + }, { I don't think passing br= makes a whole of sense for -net tap. I think it would make more sense to make sure that helper could take a shell string so you could do: -netdev tap,helper="/usr/libexec/qemu-bridge-helper --br=br0" Regards, Anthony Liguori > + .name = "helper", > + .type = QEMU_OPT_STRING, > + .help = "command to execute to configure bridge", > + }, { > .name = "sndbuf", > .type = QEMU_OPT_SIZE, > .help = "send buffer limit" > @@ -1049,6 +1057,23 @@ static const struct { > { /* end of list */ } > }, > }, > + [NET_CLIENT_TYPE_BRIDGE] = { > + .type = "bridge", > + .init = net_init_bridge, > + .desc = { > + NET_COMMON_PARAMS_DESC, > + { > + .name = "br", > + .type = QEMU_OPT_STRING, > + .help = "bridge name", > + }, { > + .name = "helper", > + .type = QEMU_OPT_STRING, > + .help = "command to execute to configure bridge", > + }, > + { /* end of list */ } > + }, > + }, > }; > > int net_client_init(Monitor *mon, QemuOpts *opts, int is_netdev) > @@ -1071,7 +1096,8 @@ int net_client_init(Monitor *mon, QemuOpts *opts, int is_netdev) > #ifdef CONFIG_VDE > strcmp(type, "vde") != 0&& > #endif > - strcmp(type, "socket") != 0) { > + strcmp(type, "socket") != 0&& > + strcmp(type, "bridge") != 0) { > qerror_report(QERR_INVALID_PARAMETER_VALUE, "type", > "a netdev backend type"); > return -1; > @@ -1141,6 +1167,7 @@ static int net_host_check_device(const char *device) > #ifdef CONFIG_VDE > ,"vde" > #endif > + , "bridge" > }; > for (i = 0; i< sizeof(valid_param_list) / sizeof(char *); i++) { > if (!strncmp(valid_param_list[i], device, > diff --git a/net.h b/net.h > index c6b4190..0fd7e23 100644 > --- a/net.h > +++ b/net.h > @@ -36,6 +36,7 @@ typedef enum { > NET_CLIENT_TYPE_SOCKET, > NET_CLIENT_TYPE_VDE, > NET_CLIENT_TYPE_DUMP, > + NET_CLIENT_TYPE_BRIDGE, > > NET_CLIENT_TYPE_MAX > } net_client_type; > @@ -173,6 +174,8 @@ int do_netdev_del(Monitor *mon, const QDict *qdict, QObject **ret_data); > > #define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup" > #define DEFAULT_NETWORK_DOWN_SCRIPT "/etc/qemu-ifdown" > +#define DEFAULT_BRIDGE_HELPER CONFIG_QEMU_HELPERDIR "/qemu-bridge-helper" > +#define DEFAULT_BRIDGE_INTERFACE "br0" > > void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd); > > diff --git a/net/tap.c b/net/tap.c > index 6c27a94..b2b82a1 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -382,6 +382,143 @@ static int launch_script(const char *setup_script, const char *ifname, int fd) > return -1; > } > > +static int recv_fd(int c) > +{ > + int fd; > + uint8_t msgbuf[CMSG_SPACE(sizeof(fd))]; > + struct msghdr msg = { > + .msg_control = msgbuf, > + .msg_controllen = sizeof(msgbuf), > + }; > + struct cmsghdr *cmsg; > + struct iovec iov; > + uint8_t req[1]; > + ssize_t len; > + > + cmsg = CMSG_FIRSTHDR(&msg); > + cmsg->cmsg_level = SOL_SOCKET; > + cmsg->cmsg_type = SCM_RIGHTS; > + cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); > + msg.msg_controllen = cmsg->cmsg_len; > + > + iov.iov_base = req; > + iov.iov_len = sizeof(req); > + > + msg.msg_iov =&iov; > + msg.msg_iovlen = 1; > + > + len = recvmsg(c,&msg, 0); > + if (len> 0) { > + memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd)); > + return fd; > + } > + > + return len; > +} > + > +static int net_bridge_run_helper(const char *helper, const char *bridge) > +{ > + sigset_t oldmask, mask; > + int pid, status; > + char *args[5]; > + char **parg; > + int sv[2]; > + > + sigemptyset(&mask); > + sigaddset(&mask, SIGCHLD); > + sigprocmask(SIG_BLOCK,&mask,&oldmask); > + > + if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) { > + return -1; > + } > + > + /* try to launch bridge helper */ > + pid = fork(); > + if (pid == 0) { > + int open_max = sysconf(_SC_OPEN_MAX), i; > + char buf[32]; > + > + snprintf(buf, sizeof(buf), "%d", sv[1]); > + > + for (i = 0; i< open_max; i++) { > + if (i != STDIN_FILENO&& > + i != STDOUT_FILENO&& > + i != STDERR_FILENO&& > + i != sv[1]) { > + close(i); > + } > + } > + parg = args; > + *parg++ = (char *)helper; > + *parg++ = (char *)"--use-vnet"; > + *parg++ = (char *)bridge; > + *parg++ = buf; > + *parg++ = NULL; > + execv(helper, args); > + _exit(1); > + } else if (pid> 0) { > + int fd; > + > + close(sv[1]); > + > + do { > + fd = recv_fd(sv[0]); > + } while (fd == -1&& errno == EINTR); > + > + close(sv[0]); > + > + while (waitpid(pid,&status, 0) != pid) { > + /* loop */ > + } > + sigprocmask(SIG_SETMASK,&oldmask, NULL); > + if (fd< 0) { > + fprintf(stderr, "failed to recv file descriptor\n"); > + return -1; > + } > + > + if (WIFEXITED(status)&& WEXITSTATUS(status) == 0) { > + return fd; > + } > + } > + fprintf(stderr, "failed to launch bridge helper\n"); > + return -1; > +} > + > +int net_init_bridge(QemuOpts *opts, Monitor *mon, const char *name, > + VLANState *vlan) > +{ > + TAPState *s; > + int fd, vnet_hdr; > + > + if (!qemu_opt_get(opts, "br")) { > + qemu_opt_set(opts, "br", DEFAULT_BRIDGE_INTERFACE); > + } > + if (!qemu_opt_get(opts, "helper")) { > + qemu_opt_set(opts, "helper", DEFAULT_BRIDGE_HELPER); > + } > + > + 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); > + if (!s) { > + close(fd); > + return -1; > + } > + > + snprintf(s->nc.info_str, sizeof(s->nc.info_str), > + "br=%s", qemu_opt_get(opts, "br")); > + > + return 0; > +} > + > static int net_tap_init(QemuOpts *opts, int *vnet_hdr) > { > int fd, vnet_hdr_required; > @@ -422,13 +559,17 @@ int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan > { > TAPState *s; > int fd, vnet_hdr = 0; > + const char *model; > > if (qemu_opt_get(opts, "fd")) { > 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; > } > > @@ -440,7 +581,41 @@ 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); > + > + model = "tap"; > + > + } else if (qemu_opt_get(opts, "helper")) { > + 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= " > + "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); > + > + model = "bridge"; > + > } else { > + if (qemu_opt_get(opts, "br")) { > + error_report("br= is invalid with script="); > + return -1; > + } > + > if (!qemu_opt_get(opts, "script")) { > qemu_opt_set(opts, "script", DEFAULT_NETWORK_SCRIPT); > } > @@ -453,9 +628,11 @@ int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan > if (fd == -1) { > return -1; > } > + > + model = "tap"; > } > > - s = net_tap_fd_init(vlan, "tap", name, fd, vnet_hdr); > + s = net_tap_fd_init(vlan, model, name, fd, vnet_hdr); > if (!s) { > close(fd); > return -1; > @@ -467,6 +644,10 @@ int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan > > if (qemu_opt_get(opts, "fd")) { > snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd); > + } else if (qemu_opt_get(opts, "helper")) { > + snprintf(s->nc.info_str, sizeof(s->nc.info_str), > + "helper=%s,br=%s", qemu_opt_get(opts, "helper"), > + qemu_opt_get(opts, "br")); > } else { > const char *ifname, *script, *downscript; > > diff --git a/net/tap.h b/net/tap.h > index e44bd2b..56c591f 100644 > --- a/net/tap.h > +++ b/net/tap.h > @@ -57,4 +57,7 @@ int tap_get_fd(VLANClientState *vc); > struct vhost_net; > struct vhost_net *tap_get_vhost_net(VLANClientState *vc); > > +int net_init_bridge(QemuOpts *opts, Monitor *mon, const char *name, > + VLANState *vlan); > + > #endif /* QEMU_NET_TAP_H */ > diff --git a/qemu-options.hx b/qemu-options.hx > index 087a3b9..4f2385d 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -1205,11 +1205,14 @@ DEF("net", HAS_ARG, QEMU_OPTION_net, > "-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][,vnet_hdr=on|off][,vhost=on|off][,vhostfd=h][,vhostforce=on|off]\n" > - " connect the host TAP network interface to VLAN 'n' and use the\n" > - " network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" > - " and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" > + "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off][,vhostfd=h][,vhostforce=on|off]\n" > + " connect the host TAP network interface to VLAN 'n' \n" > + " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" > + " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" > + " to deconfigure it\n" > " use '[down]script=no' to disable script execution\n" > + " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") and\n" > + " bridge 'br' (default=" DEFAULT_BRIDGE_INTERFACE ") to configure it\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 is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" > @@ -1219,6 +1222,10 @@ DEF("net", HAS_ARG, QEMU_OPTION_net, > " (only has effect for virtio guests which use MSIX)\n" > " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" > " use 'vhostfd=h' to connect to an already opened vhost net device\n" > + "-net bridge[,vlan=n][,name=str][,br=bridge][,helper=helper]\n" > + " connects a host TAP network interface to a host bridge device 'br'\n" > + " (default=" DEFAULT_BRIDGE_INTERFACE ") using the program 'helper'\n" > + " (default=" DEFAULT_BRIDGE_HELPER ")\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" > @@ -1242,6 +1249,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, > "user|" > #endif > "tap|" > + "bridge|" > #ifdef CONFIG_VDE > "vde|" > #endif > @@ -1378,26 +1386,66 @@ processed and applied to -net user. Mixing them with the new configuration > syntax gives undefined results. Their use for new applications is discouraged > as they will be removed from future versions. > > -@item -net tap[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,ifname=@var{name}] [,script=@var{file}][,downscript=@var{dfile}] > -Connect the host TAP network interface @var{name} to VLAN @var{n}, use > -the network script @var{file} to configure it and the network script > +@item -net tap[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}] > +Connect the host TAP network interface @var{name} to VLAN @var{n}. > + > +Use the network script @var{file} to configure it and the network script > @var{dfile} to deconfigure it. If @var{name} is not provided, the OS > -automatically provides one. @option{fd}=@var{h} can be used to specify > -the handle of an already opened host TAP interface. The default network > -configure script is @file{/etc/qemu-ifup} and the default network > -deconfigure script is @file{/etc/qemu-ifdown}. Use @option{script=no} > -or @option{downscript=no} to disable script execution. Example: > +automatically provides one. The default network configure script is > +@file{/etc/qemu-ifup} and the default network deconfigure script is > +@file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no} > +to disable script execution. > + > +If running QEMU as an unprivileged user, use the network helper > +@var{helper} to configure the TAP interface. The default network > +helper executable is @file{/usr/local/libexec/qemu-bridge-helper} > +and the default bridge device is @file{br0}. > + > +@option{fd}=@var{h} can be used to specify the handle of an already > +opened host TAP interface. > + > +Examples: > > @example > +#launch a QEMU instance with the default network script > qemu linux.img -net nic -net tap > @end example > > -More complicated example (two NICs, each one connected to a TAP device) > @example > +#launch a QEMU instance with two NICs, each one connected > +#to a TAP device > qemu linux.img -net nic,vlan=0 -net tap,vlan=0,ifname=tap0 \ > -net nic,vlan=1 -net tap,vlan=1,ifname=tap1 > @end example > > +@example > +#launch a QEMU instance with the default network helper to > +#connect a TAP device to bridge br0 > +qemu linux.img -net nic -net tap,helper=/usr/local/libexec/qemu-bridge-helper > +@end example > + > +@item -net bridge[,vlan=@var{n}][,name=@var{name}][,br=@var{bridge}][,helper=@var{helper}] > +Connect a host TAP network interface to a host bridge device. > + > +Use the network helper @var{helper} to configure the TAP interface and > +attach it to the bridge. The default network helper executable is > +@file{/usr/local/libexec/qemu-bridge-helper} and the default bridge > +device is @file{br0}. > + > +Examples: > + > +@example > +#launch a QEMU instance with the default network helper to > +#connect a TAP device to bridge br0 > +qemu linux.img -net bridge -net nic,model=virtio > +@end example > + > +@example > +#launch a QEMU instance with the default network helper to > +#connect a TAP device to bridge qemubr0 > +qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio > +@end example > + > @item -net socket[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}] [,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}] > > Connect the VLAN @var{n} to a remote VLAN in another QEMU virtual