X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/b45a9b185120a10455859341d8035cce9b441fc8..b412eb61bfd400ad70afe11ac3a5fb2931124804:/net/tap.c

diff --git a/net/tap.c b/net/tap.c
index 1f26dc9992..17e91355ce 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -34,6 +34,7 @@
 #include <net/if.h>
 
 #include "net.h"
+#include "monitor.h"
 #include "sysemu.h"
 #include "qemu-char.h"
 #include "qemu-common.h"
@@ -346,15 +347,10 @@ static TAPState *net_tap_fd_init(VLANState *vlan,
 
 static int launch_script(const char *setup_script, const char *ifname, int fd)
 {
-    sigset_t oldmask, mask;
     int pid, status;
     char *args[3];
     char **parg;
 
-    sigemptyset(&mask);
-    sigaddset(&mask, SIGCHLD);
-    sigprocmask(SIG_BLOCK, &mask, &oldmask);
-
     /* try to launch network script */
     pid = fork();
     if (pid == 0) {
@@ -378,7 +374,6 @@ static int launch_script(const char *setup_script, const char *ifname, int fd)
         while (waitpid(pid, &status, 0) != pid) {
             /* loop */
         }
-        sigprocmask(SIG_SETMASK, &oldmask, NULL);
 
         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
             return 0;
@@ -388,6 +383,170 @@ 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 fd_buf[6+10];
+        char br_buf[6+IFNAMSIZ] = {0};
+        char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
+
+        for (i = 0; i < open_max; i++) {
+            if (i != STDIN_FILENO &&
+                i != STDOUT_FILENO &&
+                i != STDERR_FILENO &&
+                i != sv[1]) {
+                close(i);
+            }
+        }
+
+        snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
+
+        if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
+            /* assume helper is a command */
+
+            if (strstr(helper, "--br=") == NULL) {
+                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);
+
+            parg = args;
+            *parg++ = (char *)"sh";
+            *parg++ = (char *)"-c";
+            *parg++ = helper_cmd;
+            *parg++ = NULL;
+
+            execv("/bin/sh", args);
+        } else {
+            /* assume helper is just the executable path name */
+
+            snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
+
+            parg = args;
+            *parg++ = (char *)helper;
+            *parg++ = (char *)"--use-vnet";
+            *parg++ = fd_buf;
+            *parg++ = br_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, 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), "helper=%s,br=%s",
+             qemu_opt_get(opts, "helper"), qemu_opt_get(opts, "br"));
+
+    return 0;
+}
+
 static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
 {
     int fd, vnet_hdr_required;
@@ -424,21 +583,46 @@ static int net_tap_init(QemuOpts *opts, int *vnet_hdr)
     return fd;
 }
 
-int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan)
+int net_init_tap(QemuOpts *opts, 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") ||
+            qemu_opt_get(opts, "helper")) {
+            error_report("ifname=, script=, downscript=, vnet_hdr=, "
+                         "and helper= are invalid with fd=");
+            return -1;
+        }
+
+        fd = net_handle_fd_param(cur_mon, qemu_opt_get(opts, "fd"));
+        if (fd == -1) {
+            return -1;
+        }
+
+        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= is invalid with fd=");
+            error_report("ifname=, script=, downscript=, and vnet_hdr= "
+                         "are invalid with helper=");
             return -1;
         }
 
-        fd = net_handle_fd_param(mon, qemu_opt_get(opts, "fd"));
+        fd = net_bridge_run_helper(qemu_opt_get(opts, "helper"),
+                                   DEFAULT_BRIDGE_INTERFACE);
         if (fd == -1) {
             return -1;
         }
@@ -446,6 +630,9 @@ 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 = "bridge";
+
     } else {
         if (!qemu_opt_get(opts, "script")) {
             qemu_opt_set(opts, "script", DEFAULT_NETWORK_SCRIPT);
@@ -459,9 +646,11 @@ 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;
@@ -473,6 +662,9 @@ 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", qemu_opt_get(opts, "helper"));
     } else {
         const char *ifname, *script, *downscript;
 
@@ -495,7 +687,7 @@ int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan
         int vhostfd, r;
         bool force = qemu_opt_get_bool(opts, "vhostforce", false);
         if (qemu_opt_get(opts, "vhostfd")) {
-            r = net_handle_fd_param(mon, qemu_opt_get(opts, "vhostfd"));
+            r = net_handle_fd_param(cur_mon, qemu_opt_get(opts, "vhostfd"));
             if (r == -1) {
                 return -1;
             }