[ovs-dev] [netdev 22/27] netdev-linux, netdev-bsd: Make access to AF_INET socket thread-safe.

Ben Pfaff blp at nicira.com
Thu Aug 1 21:29:45 UTC 2013


The only uses of 'af_inet_sock', in both drivers, were ioctls, so it seemed
like a good abstraction to write a function that just does such an ioctl,
and to factor out shared code into socket-util.

Signed-off-by: Ben Pfaff <blp at nicira.com>
CC: Ed Maste <emaste at freebsd.org>
---
 lib/netdev-bsd.c   |   84 +++++++++++++---------------------
 lib/netdev-linux.c |  127 +++++++++++++++++++---------------------------------
 lib/netdev-linux.h |    3 +-
 lib/socket-util.c  |   40 +++++++++++++++++
 lib/socket-util.h  |    8 +++-
 lib/vlandev.c      |    9 +---
 6 files changed, 128 insertions(+), 143 deletions(-)

diff --git a/lib/netdev-bsd.c b/lib/netdev-bsd.c
index d6a8631..503207f 100644
--- a/lib/netdev-bsd.c
+++ b/lib/netdev-bsd.c
@@ -107,9 +107,6 @@ enum {
     VALID_CARRIER = 1 << 5
 };
 
-/* An AF_INET socket (used for ioctl operations). */
-static int af_inet_sock = -1;
-
 #if defined(__NetBSD__)
 /* AF_LINK socket used for netdev_bsd_get_stats and set_etheraddr */
 static int af_link_sock = -1;
@@ -133,8 +130,6 @@ static int cache_notifier_refcount;
 
 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
 
-static int netdev_bsd_do_ioctl(const char *, struct ifreq *, unsigned long cmd,
-                               const char *cmd_name);
 static void destroy_tap(int fd, const char *name);
 static int get_flags(const struct netdev *, int *flagsp);
 static int set_flags(const char *, int flags);
@@ -181,30 +176,23 @@ netdev_get_kernel_name(const struct netdev *netdev)
 static int
 netdev_bsd_init(void)
 {
+#if defined(__NetBSD__)
     static int status = -1;
 
     if (status >= 0) {  /* already initialized */
         return status;
     }
 
-    af_inet_sock = socket(AF_INET, SOCK_DGRAM, 0);
-    status = af_inet_sock >= 0 ? 0 : errno;
-    if (status) {
-        VLOG_ERR("failed to create inet socket: %s", ovs_strerror(status));
-        return status;
-    }
-
-#if defined(__NetBSD__)
     af_link_sock = socket(AF_LINK, SOCK_DGRAM, 0);
     status = af_link_sock >= 0 ? 0 : errno;
     if (status) {
         VLOG_ERR("failed to create link socket: %s", ovs_strerror(status));
-        close(af_inet_sock);
-        af_inet_sock = -1;
     }
-#endif /* defined(__NetBSD__) */
 
     return status;
+#else
+    return 0;
+#endif /* defined(__NetBSD__) */
 }
 
 /*
@@ -381,8 +369,8 @@ netdev_bsd_create_tap(const struct netdev_class *class, const char *name,
     /* Change the name of the tap device */
 #if defined(SIOCSIFNAME)
     ifr.ifr_data = (void *)name;
-    if (ioctl(af_inet_sock, SIOCSIFNAME, &ifr) == -1) {
-        error = errno;
+    error = af_inet_ioctl(SIOCSIFNAME, &ifr);
+    if (error) {
         destroy_tap(netdev->tap_fd, ifr.ifr_name);
         goto error_unref_notifier;
     }
@@ -405,8 +393,8 @@ netdev_bsd_create_tap(const struct netdev_class *class, const char *name,
     /* Turn device UP */
     ifr_set_flags(&ifr, IFF_UP);
     strncpy(ifr.ifr_name, kernel_name, sizeof ifr.ifr_name);
-    if (ioctl(af_inet_sock, SIOCSIFFLAGS, &ifr) == -1) {
-        error = errno;
+    error = af_inet_ioctl(SIOCSIFFLAGS, &ifr);
+    if (error) {
         destroy_tap(netdev->tap_fd, kernel_name);
         goto error_unref_notifier;
     }
@@ -815,7 +803,7 @@ netdev_bsd_get_mtu(const struct netdev *netdev_, int *mtup)
         struct ifreq ifr;
         int error;
 
-        error = netdev_bsd_do_ioctl(netdev_get_kernel_name(netdev_), &ifr,
+        error = af_inet_ifreq_ioctl(netdev_get_kernel_name(netdev_), &ifr,
                                     SIOCGIFMTU, "SIOCGIFMTU");
         if (error) {
             return error;
@@ -844,15 +832,17 @@ netdev_bsd_get_carrier(const struct netdev *netdev_, bool *carrier)
 
     if (!(netdev->cache_valid & VALID_CARRIER)) {
         struct ifmediareq ifmr;
+        int error;
 
         memset(&ifmr, 0, sizeof(ifmr));
         strncpy(ifmr.ifm_name, netdev_get_kernel_name(netdev_),
                 sizeof ifmr.ifm_name);
 
-        if (ioctl(af_inet_sock, SIOCGIFMEDIA, &ifmr) == -1) {
+        error = af_inet_ioctl(SIOCGIFMEDIA, &ifmr);
+        if (error) {
             VLOG_DBG_RL(&rl, "%s: ioctl(SIOCGIFMEDIA) failed: %s",
-                        netdev_get_name(netdev_), ovs_strerror(errno));
-            return errno;
+                        netdev_get_name(netdev_), ovs_strerror(error));
+            return error;
         }
 
         netdev->carrier = (ifmr.ifm_status & IFM_ACTIVE) == IFM_ACTIVE;
@@ -1057,10 +1047,11 @@ netdev_bsd_get_features(const struct netdev *netdev,
     /* We make two SIOCGIFMEDIA ioctl calls.  The first to determine the
      * number of supported modes, and a second with a buffer to retrieve
      * them. */
-    if (ioctl(af_inet_sock, SIOCGIFMEDIA, &ifmr) == -1) {
+    error = af_inet_ioctl(SIOCGIFMEDIA, &ifmr);
+    if (error) {
         VLOG_DBG_RL(&rl, "%s: ioctl(SIOCGIFMEDIA) failed: %s",
-                    netdev_get_name(netdev), ovs_strerror(errno));
-        return errno;
+                    netdev_get_name(netdev), ovs_strerror(error));
+        return error;
     }
 
     media_list = xcalloc(ifmr.ifm_count, sizeof(int));
@@ -1073,10 +1064,10 @@ netdev_bsd_get_features(const struct netdev *netdev,
         goto cleanup;
     }
 
-    if (ioctl(af_inet_sock, SIOCGIFMEDIA, &ifmr) == -1) {
+    error = af_inet_ioctl(SIOCGIFMEDIA, &ifmr);
+    if (error) {
         VLOG_DBG_RL(&rl, "%s: ioctl(SIOCGIFMEDIA) failed: %s",
-                    netdev_get_name(netdev), ovs_strerror(errno));
-        error = errno;
+                    netdev_get_name(netdev), ovs_strerror(error));
         goto cleanup;
     }
 
@@ -1117,7 +1108,7 @@ netdev_bsd_get_in4(const struct netdev *netdev_, struct in_addr *in4,
         int error;
 
         ifr.ifr_addr.sa_family = AF_INET;
-        error = netdev_bsd_do_ioctl(netdev_get_kernel_name(netdev_), &ifr,
+        error = af_inet_ifreq_ioctl(netdev_get_kernel_name(netdev_), &ifr,
                                     SIOCGIFADDR, "SIOCGIFADDR");
         if (error) {
             return error;
@@ -1125,7 +1116,7 @@ netdev_bsd_get_in4(const struct netdev *netdev_, struct in_addr *in4,
 
         sin = (struct sockaddr_in *) &ifr.ifr_addr;
         netdev->in4 = sin->sin_addr;
-        error = netdev_bsd_do_ioctl(netdev_get_kernel_name(netdev_), &ifr,
+        error = af_inet_ifreq_ioctl(netdev_get_kernel_name(netdev_), &ifr,
                                     SIOCGIFNETMASK, "SIOCGIFNETMASK");
         if (error) {
             return error;
@@ -1348,7 +1339,7 @@ do_set_addr(struct netdev *netdev,
 {
     struct ifreq ifr;
     make_in4_sockaddr(&ifr.ifr_addr, addr);
-    return netdev_bsd_do_ioctl(netdev_get_kernel_name(netdev), &ifr, ioctl_nr,
+    return af_inet_ifreq_ioctl(netdev_get_kernel_name(netdev), &ifr, ioctl_nr,
                                ioctl_name);
 }
 
@@ -1534,7 +1525,7 @@ destroy_tap(int fd, const char *name)
     close(fd);
     strcpy(ifr.ifr_name, name);
     /* XXX What to do if this call fails? */
-    ioctl(af_inet_sock, SIOCIFDESTROY, &ifr);
+    af_inet_ioctl(SIOCIFDESTROY, &ifr);
 }
 
 static int
@@ -1543,7 +1534,7 @@ get_flags(const struct netdev *netdev, int *flags)
     struct ifreq ifr;
     int error;
 
-    error = netdev_bsd_do_ioctl(netdev_get_kernel_name(netdev), &ifr,
+    error = af_inet_ifreq_ioctl(netdev_get_kernel_name(netdev), &ifr,
                                 SIOCGIFFLAGS, "SIOCGIFFLAGS");
 
     *flags = ifr_get_flags(&ifr);
@@ -1558,7 +1549,7 @@ set_flags(const char *name, int flags)
 
     ifr_set_flags(&ifr, flags);
 
-    return netdev_bsd_do_ioctl(name, &ifr, SIOCSIFFLAGS, "SIOCSIFFLAGS");
+    return af_inet_ifreq_ioctl(name, &ifr, SIOCSIFFLAGS, "SIOCSIFFLAGS");
 }
 
 static int
@@ -1616,16 +1607,18 @@ set_etheraddr(const char *netdev_name OVS_UNUSED, int hwaddr_family OVS_UNUSED,
 {
 #if defined(__FreeBSD__)
     struct ifreq ifr;
+    int error;
 
     memset(&ifr, 0, sizeof ifr);
     strncpy(ifr.ifr_name, netdev_name, sizeof ifr.ifr_name);
     ifr.ifr_addr.sa_family = hwaddr_family;
     ifr.ifr_addr.sa_len = hwaddr_len;
     memcpy(ifr.ifr_addr.sa_data, mac, hwaddr_len);
-    if (ioctl(af_inet_sock, SIOCSIFLLADDR, &ifr) < 0) {
+    error = af_inet_ioctl(SIOCSIFLLADDR, &ifr);
+    if (error) {
         VLOG_ERR("ioctl(SIOCSIFLLADDR) on %s device failed: %s",
-                 netdev_name, ovs_strerror(errno));
-        return errno;
+                 netdev_name, ovs_strerror(error));
+        return error;
     }
     return 0;
 #elif defined(__NetBSD__)
@@ -1684,19 +1677,6 @@ set_etheraddr(const char *netdev_name OVS_UNUSED, int hwaddr_family OVS_UNUSED,
 }
 
 static int
-netdev_bsd_do_ioctl(const char *name, struct ifreq *ifr, unsigned long cmd,
-                    const char *cmd_name)
-{
-    strncpy(ifr->ifr_name, name, sizeof ifr->ifr_name);
-    if (ioctl(af_inet_sock, cmd, ifr) == -1) {
-        VLOG_DBG_RL(&rl, "%s: ioctl(%s) failed: %s", name, cmd_name,
-                    ovs_strerror(errno));
-        return errno;
-    }
-    return 0;
-}
-
-static int
 ifr_get_flags(const struct ifreq *ifr)
 {
 #ifdef HAVE_STRUCT_IFREQ_IFR_FLAGSHIGH
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index c59f590..9306100 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -400,19 +400,14 @@ struct netdev_rx_linux {
 
 static const struct netdev_rx_class netdev_rx_linux_class;
 
-/* Sockets used for ioctl operations. */
-static int af_inet_sock = -1;   /* AF_INET, SOCK_DGRAM. */
-
 /* This is set pretty low because we probably won't learn anything from the
  * additional log messages. */
 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
 
-static int netdev_linux_init(void);
+static void netdev_linux_run(void);
 
 static int netdev_linux_do_ethtool(const char *name, struct ethtool_cmd *,
                                    int cmd, const char *cmd_name);
-static int netdev_linux_do_ioctl(const char *name, struct ifreq *, int cmd,
-                                 const char *cmd_name);
 static int netdev_linux_get_ipv4(const struct netdev *, struct in_addr *,
                                  int cmd, const char *cmd_name);
 static int get_flags(const struct netdev *, unsigned int *flags);
@@ -433,7 +428,7 @@ static void netdev_linux_miimon_wait(void);
 static bool
 is_netdev_linux_class(const struct netdev_class *netdev_class)
 {
-    return netdev_class->init == netdev_linux_init;
+    return netdev_class->run == netdev_linux_run;
 }
 
 static bool
@@ -457,21 +452,6 @@ netdev_rx_linux_cast(const struct netdev_rx *rx)
     return CONTAINER_OF(rx, struct netdev_rx_linux, up);
 }
 
-static int
-netdev_linux_init(void)
-{
-    static int status = -1;
-    if (status < 0) {
-        /* Create AF_INET socket. */
-        af_inet_sock = socket(AF_INET, SOCK_DGRAM, 0);
-        status = af_inet_sock >= 0 ? 0 : errno;
-        if (status) {
-            VLOG_ERR("failed to create inet socket: %s", ovs_strerror(status));
-        }
-    }
-    return status;
-}
-
 static void
 netdev_linux_run(void)
 {
@@ -721,13 +701,15 @@ netdev_linux_rx_open(struct netdev *netdev_, struct netdev_rx **rxp)
         struct sockaddr_ll sll;
         int ifindex;
         /* Result of tcpdump -dd inbound */
-        static struct sock_filter filt[] = {
+        static const struct sock_filter filt[] = {
             { 0x28, 0, 0, 0xfffff004 }, /* ldh [0] */
             { 0x15, 0, 1, 0x00000004 }, /* jeq #4     jt 2  jf 3 */
             { 0x6, 0, 0, 0x00000000 },  /* ret #0 */
             { 0x6, 0, 0, 0x0000ffff }   /* ret #65535 */
         };
-        static struct sock_fprog fprog = { ARRAY_SIZE(filt), filt };
+        static const struct sock_fprog fprog = {
+            ARRAY_SIZE(filt), (struct sock_filter *) filt
+        };
 
         /* Create file descriptor. */
         fd = socket(PF_PACKET, SOCK_RAW, 0);
@@ -766,7 +748,7 @@ netdev_linux_rx_open(struct netdev *netdev_, struct netdev_rx **rxp)
                            sizeof fprog);
         if (error) {
             error = errno;
-            VLOG_ERR("%s: failed attach filter (%s)",
+            VLOG_ERR("%s: failed to attach filter (%s)",
                      netdev_get_name(netdev_), ovs_strerror(error));
             goto error;
         }
@@ -834,8 +816,8 @@ netdev_rx_linux_drain(struct netdev_rx *rx_)
     struct netdev_rx_linux *rx = netdev_rx_linux_cast(rx_);
     if (rx->is_tap) {
         struct ifreq ifr;
-        int error = netdev_linux_do_ioctl(netdev_rx_get_name(rx_), &ifr,
-                                          SIOCGIFTXQLEN, "SIOCGIFTXQLEN");
+        int error = af_inet_ifreq_ioctl(netdev_rx_get_name(rx_), &ifr,
+                                        SIOCGIFTXQLEN, "SIOCGIFTXQLEN");
         if (error) {
             return error;
         }
@@ -1019,8 +1001,8 @@ netdev_linux_get_mtu(const struct netdev *netdev_, int *mtup)
         struct ifreq ifr;
         int error;
 
-        error = netdev_linux_do_ioctl(netdev_get_name(netdev_), &ifr,
-                                      SIOCGIFMTU, "SIOCGIFMTU");
+        error = af_inet_ifreq_ioctl(netdev_get_name(netdev_), &ifr,
+                                    SIOCGIFMTU, "SIOCGIFMTU");
 
         netdev->netdev_mtu_error = error;
         netdev->mtu = ifr.ifr_mtu;
@@ -1053,8 +1035,8 @@ netdev_linux_set_mtu(const struct netdev *netdev_, int mtu)
         netdev->cache_valid &= ~VALID_MTU;
     }
     ifr.ifr_mtu = mtu;
-    error = netdev_linux_do_ioctl(netdev_get_name(netdev_), &ifr,
-                                  SIOCSIFMTU, "SIOCSIFMTU");
+    error = af_inet_ifreq_ioctl(netdev_get_name(netdev_), &ifr,
+                                SIOCSIFMTU, "SIOCSIFMTU");
     if (!error || error == ENODEV) {
         netdev->netdev_mtu_error = error;
         netdev->mtu = ifr.ifr_mtu;
@@ -1103,7 +1085,7 @@ netdev_linux_do_miimon(const char *name, int cmd, const char *cmd_name,
 
     memset(&ifr, 0, sizeof ifr);
     memcpy(&ifr.ifr_data, data, sizeof *data);
-    error = netdev_linux_do_ioctl(name, &ifr, cmd, cmd_name);
+    error = af_inet_ifreq_ioctl(name, &ifr, cmd, cmd_name);
     memcpy(data, &ifr.ifr_data, sizeof *data);
 
     return error;
@@ -2191,11 +2173,10 @@ do_set_addr(struct netdev *netdev,
             int ioctl_nr, const char *ioctl_name, struct in_addr addr)
 {
     struct ifreq ifr;
-    ovs_strzcpy(ifr.ifr_name, netdev_get_name(netdev), sizeof ifr.ifr_name);
-    make_in4_sockaddr(&ifr.ifr_addr, addr);
 
-    return netdev_linux_do_ioctl(netdev_get_name(netdev), &ifr, ioctl_nr,
-                                 ioctl_name);
+    make_in4_sockaddr(&ifr.ifr_addr, addr);
+    return af_inet_ifreq_ioctl(netdev_get_name(netdev), &ifr, ioctl_nr,
+                               ioctl_name);
 }
 
 /* Adds 'router' as a default IP gateway. */
@@ -2211,7 +2192,7 @@ netdev_linux_add_router(struct netdev *netdev OVS_UNUSED, struct in_addr router)
     make_in4_sockaddr(&rt.rt_gateway, router);
     make_in4_sockaddr(&rt.rt_genmask, any);
     rt.rt_flags = RTF_UP | RTF_GATEWAY;
-    error = ioctl(af_inet_sock, SIOCADDRT, &rt) < 0 ? errno : 0;
+    error = af_inet_ioctl(SIOCADDRT, &rt);
     if (error) {
         VLOG_WARN("ioctl(SIOCADDRT): %s", ovs_strerror(error));
     }
@@ -2337,7 +2318,7 @@ netdev_linux_arp_lookup(const struct netdev *netdev,
     r.arp_flags = 0;
     ovs_strzcpy(r.arp_dev, netdev_get_name(netdev), sizeof r.arp_dev);
     COVERAGE_INC(netdev_arp_lookup);
-    retval = ioctl(af_inet_sock, SIOCGARP, &r) < 0 ? errno : 0;
+    retval = af_inet_ioctl(SIOCGARP, &r);
     if (!retval) {
         memcpy(mac, r.arp_ha.sa_data, ETH_ADDR_LEN);
     } else if (retval != ENXIO) {
@@ -2403,7 +2384,7 @@ netdev_linux_change_seq(const struct netdev *netdev)
 {                                                               \
     NAME,                                                       \
                                                                 \
-    netdev_linux_init,                                          \
+    NULL,                                                       \
     netdev_linux_run,                                           \
     netdev_linux_wait,                                          \
                                                                 \
@@ -4193,14 +4174,6 @@ tc_calc_buffer(unsigned int Bps, int mtu, uint64_t burst_bytes)
 
 /* Linux-only functions declared in netdev-linux.h  */
 
-/* Returns a fd for an AF_INET socket or a negative errno value. */
-int
-netdev_linux_get_af_inet_sock(void)
-{
-    int error = netdev_linux_init();
-    return error ? -error : af_inet_sock;
-}
-
 /* Modifies the 'flag' bit in ethtool's flags field for 'netdev'.  If
  * 'enable' is true, the bit is set.  Otherwise, it is cleared. */
 int
@@ -4393,8 +4366,7 @@ get_flags(const struct netdev *dev, unsigned int *flags)
     int error;
 
     *flags = 0;
-    error = netdev_linux_do_ioctl(dev->name, &ifr, SIOCGIFFLAGS,
-                                  "SIOCGIFFLAGS");
+    error = af_inet_ifreq_ioctl(dev->name, &ifr, SIOCGIFFLAGS, "SIOCGIFFLAGS");
     if (!error) {
         *flags = ifr.ifr_flags;
     }
@@ -4407,20 +4379,23 @@ set_flags(const char *name, unsigned int flags)
     struct ifreq ifr;
 
     ifr.ifr_flags = flags;
-    return netdev_linux_do_ioctl(name, &ifr, SIOCSIFFLAGS, "SIOCSIFFLAGS");
+    return af_inet_ifreq_ioctl(name, &ifr, SIOCSIFFLAGS, "SIOCSIFFLAGS");
 }
 
 static int
 do_get_ifindex(const char *netdev_name)
 {
     struct ifreq ifr;
+    int error;
 
     ovs_strzcpy(ifr.ifr_name, netdev_name, sizeof ifr.ifr_name);
     COVERAGE_INC(netdev_get_ifindex);
-    if (ioctl(af_inet_sock, SIOCGIFINDEX, &ifr) < 0) {
+
+    error = af_inet_ioctl(SIOCGIFINDEX, &ifr);
+    if (error) {
         VLOG_WARN_RL(&rl, "ioctl(SIOCGIFINDEX) on %s device failed: %s",
-                     netdev_name, ovs_strerror(errno));
-        return -errno;
+                     netdev_name, ovs_strerror(error));
+        return -error;
     }
     return ifr.ifr_ifindex;
 }
@@ -4452,18 +4427,20 @@ get_etheraddr(const char *netdev_name, uint8_t ea[ETH_ADDR_LEN])
 {
     struct ifreq ifr;
     int hwaddr_family;
+    int error;
 
     memset(&ifr, 0, sizeof ifr);
     ovs_strzcpy(ifr.ifr_name, netdev_name, sizeof ifr.ifr_name);
     COVERAGE_INC(netdev_get_hwaddr);
-    if (ioctl(af_inet_sock, SIOCGIFHWADDR, &ifr) < 0) {
+    error = af_inet_ioctl(SIOCGIFHWADDR, &ifr);
+    if (error) {
         /* ENODEV probably means that a vif disappeared asynchronously and
          * hasn't been removed from the database yet, so reduce the log level
          * to INFO for that case. */
-        VLOG(errno == ENODEV ? VLL_INFO : VLL_ERR,
+        VLOG(error == ENODEV ? VLL_INFO : VLL_ERR,
              "ioctl(SIOCGIFHWADDR) on %s device failed: %s",
-             netdev_name, ovs_strerror(errno));
-        return errno;
+             netdev_name, ovs_strerror(error));
+        return error;
     }
     hwaddr_family = ifr.ifr_hwaddr.sa_family;
     if (hwaddr_family != AF_UNSPEC && hwaddr_family != ARPHRD_ETHER) {
@@ -4479,18 +4456,19 @@ set_etheraddr(const char *netdev_name,
               const uint8_t mac[ETH_ADDR_LEN])
 {
     struct ifreq ifr;
+    int error;
 
     memset(&ifr, 0, sizeof ifr);
     ovs_strzcpy(ifr.ifr_name, netdev_name, sizeof ifr.ifr_name);
     ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
     memcpy(ifr.ifr_hwaddr.sa_data, mac, ETH_ADDR_LEN);
     COVERAGE_INC(netdev_set_hwaddr);
-    if (ioctl(af_inet_sock, SIOCSIFHWADDR, &ifr) < 0) {
+    error = af_inet_ioctl(SIOCSIFHWADDR, &ifr);
+    if (error) {
         VLOG_ERR("ioctl(SIOCSIFHWADDR) on %s device failed: %s",
-                 netdev_name, ovs_strerror(errno));
-        return errno;
+                 netdev_name, ovs_strerror(error));
     }
-    return 0;
+    return error;
 }
 
 static int
@@ -4498,37 +4476,24 @@ netdev_linux_do_ethtool(const char *name, struct ethtool_cmd *ecmd,
                         int cmd, const char *cmd_name)
 {
     struct ifreq ifr;
+    int error;
 
     memset(&ifr, 0, sizeof ifr);
     ovs_strzcpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
     ifr.ifr_data = (caddr_t) ecmd;
 
     ecmd->cmd = cmd;
-    if (ioctl(af_inet_sock, SIOCETHTOOL, &ifr) == 0) {
-        return 0;
-    } else {
-        if (errno != EOPNOTSUPP) {
+    error = af_inet_ioctl(SIOCETHTOOL, &ifr);
+    if (error) {
+        if (error != EOPNOTSUPP) {
             VLOG_WARN_RL(&rl, "ethtool command %s on network device %s "
-                         "failed: %s", cmd_name, name, ovs_strerror(errno));
+                         "failed: %s", cmd_name, name, ovs_strerror(error));
         } else {
             /* The device doesn't support this operation.  That's pretty
              * common, so there's no point in logging anything. */
         }
-        return errno;
-    }
-}
-
-static int
-netdev_linux_do_ioctl(const char *name, struct ifreq *ifr, int cmd,
-                      const char *cmd_name)
-{
-    ovs_strzcpy(ifr->ifr_name, name, sizeof ifr->ifr_name);
-    if (ioctl(af_inet_sock, cmd, ifr) == -1) {
-        VLOG_DBG_RL(&rl, "%s: ioctl(%s) failed: %s", name, cmd_name,
-                     ovs_strerror(errno));
-        return errno;
     }
-    return 0;
+    return error;
 }
 
 static int
@@ -4539,7 +4504,7 @@ netdev_linux_get_ipv4(const struct netdev *netdev, struct in_addr *ip,
     int error;
 
     ifr.ifr_addr.sa_family = AF_INET;
-    error = netdev_linux_do_ioctl(netdev_get_name(netdev), &ifr, cmd, cmd_name);
+    error = af_inet_ifreq_ioctl(netdev_get_name(netdev), &ifr, cmd, cmd_name);
     if (!error) {
         const struct sockaddr_in *sin = ALIGNED_CAST(struct sockaddr_in *,
                                                      &ifr.ifr_addr);
diff --git a/lib/netdev-linux.h b/lib/netdev-linux.h
index 7874dd6..0c61bc9 100644
--- a/lib/netdev-linux.h
+++ b/lib/netdev-linux.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011 Nicira, Inc.
+ * Copyright (c) 2011, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,5 @@ struct netdev;
 
 int netdev_linux_ethtool_set_flag(struct netdev *netdev, uint32_t flag,
                                   const char *flag_name, bool enable);
-int netdev_linux_get_af_inet_sock(void);
 
 #endif /* netdev-linux.h */
diff --git a/lib/socket-util.c b/lib/socket-util.c
index 1d0cede..7ae6d1f 100644
--- a/lib/socket-util.c
+++ b/lib/socket-util.c
@@ -26,6 +26,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/ioctl.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -1353,3 +1354,42 @@ error:
     *n_fdsp = 0;
     return EPROTO;
 }
+
+/* Calls ioctl() on an AF_INET sock, passing the specified 'command' and
+ * 'arg'.  Returns 0 if successful, otherwise a positive errno value. */
+int
+af_inet_ioctl(int command, const void *arg)
+{
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+    static int sock;
+
+    if (ovsthread_once_start(&once)) {
+        sock = socket(AF_INET, SOCK_DGRAM, 0);
+        if (sock < 0) {
+            sock = -errno;
+            VLOG_ERR("failed to create inet socket: %s", ovs_strerror(errno));
+        }
+        ovsthread_once_done(&once);
+    }
+
+    return (sock < 0 ? -sock
+            : ioctl(sock, command, arg) == -1 ? errno
+            : 0);
+}
+
+int
+af_inet_ifreq_ioctl(const char *name, struct ifreq *ifr, int cmd,
+                    const char *cmd_name)
+{
+    int error;
+
+    ovs_strzcpy(ifr->ifr_name, name, sizeof ifr->ifr_name);
+    error = af_inet_ioctl(cmd, ifr);
+    if (error) {
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
+        VLOG_DBG_RL(&rl, "%s: ioctl(%s) failed: %s", name, cmd_name,
+                     ovs_strerror(error));
+    }
+    return error;
+}
+
diff --git a/lib/socket-util.h b/lib/socket-util.h
index 96aad5d..937e6b9 100644
--- a/lib/socket-util.h
+++ b/lib/socket-util.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -97,4 +97,10 @@ int recv_data_and_fds(int sock,
                       void *data, size_t size,
                       int fds[SOUTIL_MAX_FDS], size_t *n_fdsp);
 
+/* Helpers for calling ioctl() on an AF_INET socket. */
+struct ifreq;
+int af_inet_ioctl(int command, const void *arg);
+int af_inet_ifreq_ioctl(const char *name, struct ifreq *,
+                        int cmd, const char *cmd_name);
+
 #endif /* socket-util.h */
diff --git a/lib/vlandev.c b/lib/vlandev.c
index 5f58f10..282d28c 100644
--- a/lib/vlandev.c
+++ b/lib/vlandev.c
@@ -26,6 +26,7 @@
 #include "dummy.h"
 #include "hash.h"
 #include "shash.h"
+#include "socket-util.h"
 #include "vlog.h"
 
 VLOG_DEFINE_THIS_MODULE(vlandev);
@@ -237,17 +238,11 @@ do_vlan_ioctl(const char *netdev_name, struct vlan_ioctl_args *via,
 {
     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
     int error;
-    int sock;
 
     via->cmd = cmd;
     ovs_strlcpy(via->device1, netdev_name, sizeof via->device1);
 
-    sock = netdev_linux_get_af_inet_sock();
-    if (sock < 0) {
-        return -sock;
-    }
-
-    error = ioctl(sock, SIOCSIFVLAN, via) < 0 ? errno : 0;
+    error = af_inet_ioctl(SIOCSIFVLAN, via);
     if (error) {
         VLOG_WARN_RL(&rl, "%s: VLAN ioctl %s failed (%s)",
                      netdev_name, cmd_name, ovs_strerror(error));
-- 
1.7.10.4




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