[PATCH 3/3 v2] kvm tools: Setup bridged network by a script

[Amos Kong <kongjianjun@gmail.com>]

Use original hardcode network by default.

#./kvm run ... -n virtio --tapscript=./util/kvm-ifup-vbr0
# brctl show
bridge name     bridge id               STP enabled     interfaces
vbr0            8000.e272c7c391f4       no              tap0
guest)# ifconfig eth6
eth6      Link encap:Ethernet  HWaddr 00:11:22:33:44:55
          inet addr:192.168.33.192  Bcast:192.168.33.255  Mask:255.255.255.0
          inet6 addr: fe80::211:22ff:fe33:4455/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:22 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3725 (3.6 KiB)  TX bytes:852 (852.0 b)
guest)# ping amosk.info
PING amosk.info (69.175.108.82) 56(84) bytes of data.
64 bytes from nurpulat.uz (69.175.108.82): icmp_seq=1 ttl=43 time=306 ms

Changes from v1:
- rebased to latest tree
- replace system() by execv()

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
---
 tools/kvm/include/kvm/virtio-net.h |    1 +
 tools/kvm/kvm-run.c                |   10 +++++++++-
 tools/kvm/virtio-net.c             |   35 +++++++++++++++++++++++++----------
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/tools/kvm/include/kvm/virtio-net.h b/tools/kvm/include/kvm/virtio-net.h
index c889854..959ccb5 100644
--- a/tools/kvm/include/kvm/virtio-net.h
+++ b/tools/kvm/include/kvm/virtio-net.h
@@ -7,6 +7,7 @@ struct virtio_net_parameters {
 	struct kvm *self;
 	const char *host_ip;
 	char guest_mac[6];
+	const char *script;
 };
 
 void virtio_net__init(const struct virtio_net_parameters *params);
diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index 4007402..80e1a6c 100644
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -33,6 +33,7 @@
 #define DEFAULT_NETWORK		"virtio"
 #define DEFAULT_HOST_ADDR	"192.168.33.2"
 #define DEFAULT_GUEST_MAC	"00:11:22:33:44:55"
+#define DEFAULT_SCRIPT		"none"
 
 #define MB_SHIFT		(20)
 #define MIN_RAM_SIZE_MB		(64ULL)
@@ -65,6 +66,7 @@ static const char *kvm_dev;
 static const char *network;
 static const char *host_ip_addr;
 static const char *guest_mac;
+static const char *script;
 static bool single_step;
 static bool readonly_image;
 extern bool ioport_debug;
@@ -102,6 +104,8 @@ static const struct option options[] = {
 			"Assign this address to the host side networking"),
 	OPT_STRING('\0', "guest-mac", &guest_mac, "aa:bb:cc:dd:ee:ff",
 			"Assign this address to the guest side NIC"),
+	OPT_STRING('\0', "tapscript", &script, "Script path",
+			 "Assign a script to process created tap device"),
 	OPT_GROUP("Debug options:"),
 	OPT_STRING('d', "kvm-dev", &kvm_dev, "kvm-dev", "KVM device file"),
 	OPT_BOOLEAN('s', "single-step", &single_step,
@@ -277,6 +281,9 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 	if (!guest_mac)
 		guest_mac = DEFAULT_GUEST_MAC;
 
+	if (!script)
+		script = DEFAULT_SCRIPT;
+
 	term_init();
 
 	kvm = kvm__init(kvm_dev, ram_size);
@@ -320,7 +327,8 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 	if (!strncmp(network, "virtio", 6)) {
 		net_params = (struct virtio_net_parameters) {
 			.host_ip = host_ip_addr,
-			.self = kvm
+			.self = kvm,
+			.script = script
 		};
 		sscanf(guest_mac,	"%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
 							net_params.guest_mac,
diff --git a/tools/kvm/virtio-net.c b/tools/kvm/virtio-net.c
index 8d08272..f8d7276 100644
--- a/tools/kvm/virtio-net.c
+++ b/tools/kvm/virtio-net.c
@@ -17,6 +17,8 @@
 #include <arpa/inet.h>
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <unistd.h>
+#include <sys/wait.h>
 
 #define VIRTIO_NET_IRQ		14
 #define VIRTIO_NET_QUEUE_SIZE	128
@@ -280,7 +282,7 @@ static bool virtio_net__tap_init(const struct virtio_net_parameters *params)
 {
 	struct ifreq ifr;
 	int sock = socket(AF_INET, SOCK_STREAM, 0);
-	int i;
+	int i, pid, status;
 	struct sockaddr_in sin = {0};
 
 	for (i = 0 ; i < 6 ; i++)
@@ -304,18 +306,31 @@ static bool virtio_net__tap_init(const struct virtio_net_parameters *params)
 
 	ioctl(net_device.tap_fd, TUNSETNOCSUM, 1);
 
+	if (strcmp(params->script, "none")) {
+		pid = fork();
+		if (pid == 0) {
+			execl(params->script, params->script, net_device.tap_name, NULL);
+			_exit(1);
+		} else {
+			waitpid(pid, &status, 0);
+			if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
+				warning("Fail to setup tap by %s", params->script);
+				goto fail;
+			}
+		}
+	} else {
+		memset(&ifr, 0, sizeof(ifr));
 
-	memset(&ifr, 0, sizeof(ifr));
-
-	strncpy(ifr.ifr_name, net_device.tap_name, sizeof(net_device.tap_name));
+		strncpy(ifr.ifr_name, net_device.tap_name, sizeof(net_device.tap_name));
 
-	sin.sin_addr.s_addr = inet_addr(params->host_ip);
-	memcpy(&(ifr.ifr_addr), &sin, sizeof(ifr.ifr_addr));
-	ifr.ifr_addr.sa_family = AF_INET;
+		sin.sin_addr.s_addr = inet_addr(params->host_ip);
+		memcpy(&(ifr.ifr_addr), &sin, sizeof(ifr.ifr_addr));
+		ifr.ifr_addr.sa_family = AF_INET;
 
-	if (ioctl(sock, SIOCSIFADDR, &ifr) < 0) {
-		warning("Can not set ip address on tap device");
-		goto fail;
+		if (ioctl(sock, SIOCSIFADDR, &ifr) < 0) {
+			warning("Can not set ip address on tap device");
+			goto fail;
+		}
 	}
 
 	memset(&ifr, 0, sizeof(ifr));