[Qemu-devel] [PATCH] qemu-ga: Add guest-getip command

[Michal Privoznik]

This command returns an array of:

 [ifname, ipaddr, ipaddr_family, prefix, hwaddr]

for each interface in the system that has an IP address.
Currently, only IPv4 and IPv6 are supported.

Signed-off-by: Michal Privoznik <address@hidden>
---
 qapi-schema-guest.json     |   16 +++++
 qga/guest-agent-commands.c |  156 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 172 insertions(+), 0 deletions(-)

diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json
index 5f8a18d..14de133 100644
--- a/qapi-schema-guest.json
+++ b/qapi-schema-guest.json
@@ -219,3 +219,19 @@
 ##
 { 'command': 'guest-fsfreeze-thaw',
   'returns': 'int' }
+
+##
+# @guest-getip:
+#
+# Get list of guest IP addresses, MAC address
+# and netmasks
+#
+# Returns: List of GuestIFAddress
+#
+# Since: 1.1
+##
+{ 'type': 'GuestIFAddress',
+  'data': {'iface': {'name': 'str', 'ipaddr': 'str', 'ipaddrtype': 'int',
+                     'prefix': 'int', 'hwaddr': 'str'} } }
+{ 'command': 'guest-getip',
+  'returns': ['GuestIFAddress'] }
diff --git a/qga/guest-agent-commands.c b/qga/guest-agent-commands.c
index a09c8ca..4caffa7 100644
--- a/qga/guest-agent-commands.c
+++ b/qga/guest-agent-commands.c
@@ -5,6 +5,7 @@
  *
  * Authors:
  *  Michael Roth      <address@hidden>
+ *  Michal Privoznik  <address@hidden>
  *
  * 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 +588,154 @@ 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)
+{
+  x = ((x & 0xaaaaaaaaU) >> 1) + (x & 0x55555555U);
+  x = ((x & 0xccccccccU) >> 2) + (x & 0x33333333U);
+  x = (x >> 16) + (x & 0xffff);
+  x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f);
+  return (x >> 8) + (x & 0x00ff);
+}
+
+/*
+ * Get the list of interfaces among with their
+ * IP/MAC addresses, prefixes and IP versions
+ */
+GuestIFAddressList * qmp_guest_getip(Error **err)
+{
+    GuestIFAddressList *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 cleanup;
+    }
+
+    ifa = ifap;
+    while (ifa) {
+        GuestIFAddressList *info = NULL;
+        char addr4[INET_ADDRSTRLEN];
+        char addr6[INET6_ADDRSTRLEN];
+        unsigned char *mac_addr;
+        void *tmpAddrPtr = 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 */
+            tmpAddrPtr = &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
+            inet_ntop(AF_INET, tmpAddrPtr, 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);
+
+            /* This is safe as '1' and '0' cannot be shuffled in netmask. */
+            tmpAddrPtr = &((struct sockaddr_in *)ifa->ifa_netmask)->sin_addr;
+            info->value->iface.prefix = count_one_bits(((uint32_t *) 
tmpAddrPtr)[0]);
+        } else if (family == AF_INET6) {
+            /* interface with IPv6 address */
+            tmpAddrPtr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+            inet_ntop(AF_INET6, tmpAddrPtr, 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. */
+            tmpAddrPtr=&((struct sockaddr_in6 *)ifa->ifa_netmask)->sin6_addr;
+            info->value->iface.prefix = count_one_bits(((uint32_t *) 
tmpAddrPtr)[0]) +
+                count_one_bits(((uint32_t *) tmpAddrPtr)[1]) +
+                count_one_bits(((uint32_t *) tmpAddrPtr)[2]) +
+                count_one_bits(((uint32_t *) tmpAddrPtr)[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;
+        }
+
+        info->value->iface.ipaddrtype = family;
+
+        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 cleanup;
+        }
+
+        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 cleanup;
+        }
+
+        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 cleanup;
+        }
+
+        close(sock);
+    }
+
+cleanup:
+    freeifaddrs(ifap);
+
+    return head;
+}
-- 
1.7.3.4