[v2] qemu-ga: Add guest-network-info command

diff to v1:
-move from guest-getip to guest-network-info
-replace black boxed algorithm for population count
-several coding styles improvements

 qapi-schema-guest.json     |   29 ++++++++
 qga/guest-agent-commands.c |  163 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 192 insertions(+), 0 deletions(-)

diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json
index 5f8a18d..ca4fdc5 100644
--- a/qapi-schema-guest.json
+++ b/qapi-schema-guest.json
@@ -219,3 +219,32 @@ 
 ##
 { 'command': 'guest-fsfreeze-thaw',
   'returns': 'int' }
+
+##
+# @guest-network-info:
+#
+# Get list of guest IP addresses, MAC addresses
+# and netmasks.
+#
+# @name: The name of interface for which info are being delivered
+#
+# @ipaddr: IP address assigned to @name
+#
+# @ipaddrtype: Type of @ipaddr (e.g. ipv4, ipv6)
+#
+# @prefix: Network prefix length
+#
+# @hwaddr: Hardware address of @name
+#
+# Returns: List of GuestNetworkInfo on success.
+#
+# Since: 1.1
+##
+{ 'enum': 'GuestIpAddrType',
+  'data': [ 'ipv4', 'ipv6' ] }
+{ 'type': 'GuestNetworkInfo',
+  'data': {'iface': {'name': 'str', 'ipaddr': 'str',
+                     'ipaddrtype': 'GuestIpAddrType',
+                     'prefix': 'int', 'hwaddr': 'str'} } }
+{ 'command': 'guest-network-info',
+  'returns': ['GuestNetworkInfo'] }
diff --git a/qga/guest-agent-commands.c b/qga/guest-agent-commands.c
index a09c8ca..4843899 100644
--- a/qga/guest-agent-commands.c
+++ b/qga/guest-agent-commands.c
@@ -5,6 +5,7 @@ 
  *
  * Authors:
  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
+ *  Michal Privoznik  <mprivozn@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
@@ -23,6 +24,10 @@ 
 
 #include <sys/types.h>
 #include <sys/ioctl.h>
+#include <ifaddrs.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <net/if.h>
 #include "qga/guest-agent-core.h"
 #include "qga-qmp-commands.h"
 #include "qerror.h"
@@ -583,3 +588,161 @@  void ga_command_state_init(GAState *s, GACommandState *cs)
 #endif
     ga_command_state_add(cs, guest_file_init, NULL);
 }
+
+/* Count the number of '1' bits in @x */
+static int32_t
+count_one_bits(uint32_t x)
+{
+    uint32_t count = 0;
+    for (count = 0; x; count++) {
+        x &= x-1;
+    }
+    return count;
+}
+
+/*
+ * Get the list of interfaces among with their
+ * IP/MAC addresses, prefixes and IP versions
+ */
+GuestNetworkInfoList *qmp_guest_network_info(Error **err)
+{
+    GuestNetworkInfoList *head = NULL, *cur_item = NULL;
+    struct ifaddrs *ifap = NULL, *ifa = NULL;
+    char err_msg[512];
+
+    slog("guest-getip called");
+
+    if (getifaddrs(&ifap) < 0) {
+        snprintf(err_msg, sizeof(err_msg),
+                 "getifaddrs failed : %s", strerror(errno));
+        error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+        goto error;
+    }
+
+    ifa = ifap;
+    while (ifa) {
+        GuestNetworkInfoList *info = NULL;
+        char addr4[INET_ADDRSTRLEN];
+        char addr6[INET6_ADDRSTRLEN];
+        unsigned char *mac_addr;
+        void *tmp_addr_ptr = NULL;
+        int sock, family;
+        int mac_supported;
+        struct ifreq ifr;
+
+        /* Step over interfaces without an address */
+        if (!ifa->ifa_addr) {
+            continue;
+        }
+
+        g_debug("Processing %s interface", ifa->ifa_name);
+
+        family = ifa->ifa_addr->sa_family;
+
+        if (family == AF_INET) {
+            /* interface with IPv4 address */
+            tmp_addr_ptr = &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
+            inet_ntop(AF_INET, tmp_addr_ptr, addr4, sizeof(addr4));
+
+            info = g_malloc0(sizeof(*info));
+            info->value = g_malloc0(sizeof(*info->value));
+            info->value->iface.name = g_strdup(ifa->ifa_name);
+            info->value->iface.ipaddr = g_strdup(addr4);
+            info->value->iface.ipaddrtype = GUEST_IP_ADDR_TYPE_IPV4;
+
+            /* This is safe as '1' and '0' cannot be shuffled in netmask. */
+            tmp_addr_ptr = &((struct sockaddr_in *)ifa->ifa_netmask)->sin_addr;
+            info->value->iface.prefix =
+                count_one_bits(((uint32_t *) tmp_addr_ptr)[0]);
+        } else if (family == AF_INET6) {
+            /* interface with IPv6 address */
+            tmp_addr_ptr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+            inet_ntop(AF_INET6, tmp_addr_ptr, addr6, sizeof(addr6));
+
+            info = g_malloc0(sizeof(*info));
+            info->value = g_malloc0(sizeof(*info->value));
+            info->value->iface.name = g_strdup(ifa->ifa_name);
+            info->value->iface.ipaddr = g_strdup(addr6);
+
+            /* This is safe as '1' and '0' cannot be shuffled in netmask. */
+            tmp_addr_ptr = &((struct sockaddr_in6 *)ifa->ifa_netmask)->sin6_addr;
+            info->value->iface.prefix =
+                count_one_bits(((uint32_t *) tmp_addr_ptr)[0]) +
+                count_one_bits(((uint32_t *) tmp_addr_ptr)[1]) +
+                count_one_bits(((uint32_t *) tmp_addr_ptr)[2]) +
+                count_one_bits(((uint32_t *) tmp_addr_ptr)[3]);
+        }
+
+        /* Add new family here */
+
+        mac_supported = ifa->ifa_flags & SIOCGIFHWADDR;
+
+        ifa = ifa->ifa_next;
+
+        if (!info) {
+            continue;
+        }
+
+        if (!cur_item) {
+            head = cur_item = info;
+        } else {
+            cur_item->next = info;
+            cur_item = info;
+        }
+
+        g_debug("Appending to return: iface=%s, ip=%s, type=%llu,  prefix=%llu",
+                info->value->iface.name,
+                info->value->iface.ipaddr,
+                (unsigned long long) info->value->iface.ipaddrtype,
+                (unsigned long long) info->value->iface.prefix);
+
+        /* If we can't get get MAC address on this interface,
+         * don't even try but continue to another interface */
+        if (!mac_supported) {
+            continue;
+        }
+
+        sock = socket(PF_INET, SOCK_STREAM, 0);
+
+        if (sock == -1) {
+            snprintf(err_msg, sizeof(err_msg),
+                     "failed to create socket: %s", strerror(errno));
+            error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+            goto error;
+        }
+
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name,  info->value->iface.name, IF_NAMESIZE);
+        if (ioctl(sock, SIOCGIFHWADDR, &ifr) == -1) {
+            snprintf(err_msg, sizeof(err_msg),
+                     "failed to get MAC addres of %s: %s",
+                     info->value->iface.name,
+                     strerror(errno));
+            error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+            goto error;
+        }
+
+        mac_addr = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
+
+        if (asprintf(&info->value->iface.hwaddr,
+                     "%02x:%02x:%02x:%02x:%02x:%02x",
+                     (int) mac_addr[0], (int) mac_addr[1],
+                     (int) mac_addr[2], (int) mac_addr[3],
+                     (int) mac_addr[4], (int) mac_addr[5]) == -1) {
+            snprintf(err_msg, sizeof(err_msg),
+                     "failed to format MAC: %s", strerror(errno));
+            error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+            goto error;
+        }
+
+        close(sock);
+    }
+
+    freeifaddrs(ifap);
+    return head;
+
+error:
+    freeifaddrs(ifap);
+    qapi_free_GuestNetworkInfoList(head);
+    return NULL;
+}