net/announce.c

   1 /*
   2  *  Self-announce
   3  *  (c) 2017-2019 Red Hat, Inc.
   4  *
   5  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   6  * See the COPYING file in the top-level directory.
   7  */
   8
   9 #include "qemu/osdep.h"
  10 #include "qemu/cutils.h"
  11 #include "net/announce.h"
  12 #include "net/net.h"
  13 #include "qapi/clone-visitor.h"
  14 #include "qapi/qapi-visit-net.h"
  15 #include "qapi/qapi-commands-net.h"
  16 #include "trace.h"
  17
  18 static GData *named_timers;
  19
  20 int64_t qemu_announce_timer_step(AnnounceTimer *timer)
  21 {
  22     int64_t step;
  23
  24     step =  timer->params.initial +
  25             (timer->params.rounds - timer->round - 1) *
  26             timer->params.step;
  27
  28     if (step < 0 || step > timer->params.max) {
  29         step = timer->params.max;
  30     }
  31     timer_mod(timer->tm, qemu_clock_get_ms(timer->type) + step);
  32
  33     return step;
  34 }
  35
  36 /*
  37  * If 'free_named' is true, then remove the timer from the list
  38  * and free the timer itself.
  39  */
  40 void qemu_announce_timer_del(AnnounceTimer *timer, bool free_named)
  41 {
  42     bool free_timer = false;
  43     if (timer->tm) {
  44         timer_free(timer->tm);
  45         timer->tm = NULL;
  46     }
  47     qapi_free_strList(timer->params.interfaces);
  48     timer->params.interfaces = NULL;
  49     if (free_named && timer->params.has_id) {
  50         AnnounceTimer *list_timer;
  51         /*
  52          * Sanity check: There should only be one timer on the list with
  53          * the id.
  54          */
  55         list_timer = g_datalist_get_data(&named_timers, timer->params.id);
  56         assert(timer == list_timer);
  57         free_timer = true;
  58         g_datalist_remove_data(&named_timers, timer->params.id);
  59     }
  60     trace_qemu_announce_timer_del(free_named, free_timer, timer->params.id);
  61     g_free(timer->params.id);
  62     timer->params.id = NULL;
  63
  64     if (free_timer) {
  65         g_free(timer);
  66     }
  67 }
  68
  69 /*
  70  * Under BQL/main thread
  71  * Reset the timer to the given parameters/type/notifier.
  72  */
  73 void qemu_announce_timer_reset(AnnounceTimer *timer,
  74                                AnnounceParameters *params,
  75                                QEMUClockType type,
  76                                QEMUTimerCB *cb,
  77                                void *opaque)
  78 {
  79     /*
  80      * We're under the BQL, so the current timer can't
  81      * be firing, so we should be able to delete it.
  82      */
  83     qemu_announce_timer_del(timer, false);
  84
  85     QAPI_CLONE_MEMBERS(AnnounceParameters, &timer->params, params);
  86     timer->round = params->rounds;
  87     timer->type = type;
  88     timer->tm = timer_new_ms(type, cb, opaque);
  89 }
  90
  91 #ifndef ETH_P_RARP
  92 #define ETH_P_RARP 0x8035
  93 #endif
  94 #define ARP_HTYPE_ETH 0x0001
  95 #define ARP_PTYPE_IP 0x0800
  96 #define ARP_OP_REQUEST_REV 0x3
  97
  98 static int announce_self_create(uint8_t *buf,
  99                                 uint8_t *mac_addr)
 100 {
 101     /* Ethernet header. */
 102     memset(buf, 0xff, 6);         /* destination MAC addr */
 103     memcpy(buf + 6, mac_addr, 6); /* source MAC addr */
 104     *(uint16_t *)(buf + 12) = htons(ETH_P_RARP); /* ethertype */
 105
 106     /* RARP header. */
 107     *(uint16_t *)(buf + 14) = htons(ARP_HTYPE_ETH); /* hardware addr space */
 108     *(uint16_t *)(buf + 16) = htons(ARP_PTYPE_IP); /* protocol addr space */
 109     *(buf + 18) = 6; /* hardware addr length (ethernet) */
 110     *(buf + 19) = 4; /* protocol addr length (IPv4) */
 111     *(uint16_t *)(buf + 20) = htons(ARP_OP_REQUEST_REV); /* opcode */
 112     memcpy(buf + 22, mac_addr, 6); /* source hw addr */
 113     memset(buf + 28, 0x00, 4);     /* source protocol addr */
 114     memcpy(buf + 32, mac_addr, 6); /* target hw addr */
 115     memset(buf + 38, 0x00, 4);     /* target protocol addr */
 116
 117     /* Padding to get up to 60 bytes (ethernet min packet size, minus FCS). */
 118     memset(buf + 42, 0x00, 18);
 119
 120     return 60; /* len (FCS will be added by hardware) */
 121 }
 122
 123 /*
 124  * Helper to print ethernet mac address
 125  */
 126 static const char *qemu_ether_ntoa(const MACAddr *mac)
 127 {
 128     static char ret[18];
 129
 130     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 131              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 132
 133     return ret;
 134 }
 135
 136 static void qemu_announce_self_iter(NICState *nic, void *opaque)
 137 {
 138     AnnounceTimer *timer = opaque;
 139     uint8_t buf[60];
 140     int len;
 141     bool skip;
 142
 143     if (timer->params.has_interfaces) {
 144         strList *entry = timer->params.interfaces;
 145         /* Skip unless we find our name in the requested list */
 146         skip = true;
 147
 148         while (entry) {
 149             if (!strcmp(entry->value, nic->ncs->name)) {
 150                 /* Found us */
 151                 skip = false;
 152                 break;
 153             }
 154             entry = entry->next;
 155         }
 156     } else {
 157         skip = false;
 158     }
 159
 160     trace_qemu_announce_self_iter(timer->params.has_id ? timer->params.id : "_",
 161                                   nic->ncs->name,
 162                                   qemu_ether_ntoa(&nic->conf->macaddr), skip);
 163
 164     if (!skip) {
 165         len = announce_self_create(buf, nic->conf->macaddr.a);
 166
 167         qemu_send_packet_raw(qemu_get_queue(nic), buf, len);
 168
 169         /* if the NIC provides it's own announcement support, use it as well */
 170         if (nic->ncs->info->announce) {
 171             nic->ncs->info->announce(nic->ncs);
 172         }
 173     }
 174 }
 175 static void qemu_announce_self_once(void *opaque)
 176 {
 177     AnnounceTimer *timer = (AnnounceTimer *)opaque;
 178
 179     qemu_foreach_nic(qemu_announce_self_iter, timer);
 180
 181     if (--timer->round) {
 182         qemu_announce_timer_step(timer);
 183     } else {
 184         qemu_announce_timer_del(timer, true);
 185     }
 186 }
 187
 188 void qemu_announce_self(AnnounceTimer *timer, AnnounceParameters *params)
 189 {
 190     qemu_announce_timer_reset(timer, params, QEMU_CLOCK_REALTIME,
 191                               qemu_announce_self_once, timer);
 192     if (params->rounds) {
 193         qemu_announce_self_once(timer);
 194     } else {
 195         qemu_announce_timer_del(timer, true);
 196     }
 197 }
 198
 199 void qmp_announce_self(AnnounceParameters *params, Error **errp)
 200 {
 201     AnnounceTimer *named_timer;
 202     if (!params->has_id) {
 203         params->id = g_strdup("");
 204         params->has_id = true;
 205     }
 206
 207     named_timer = g_datalist_get_data(&named_timers, params->id);
 208
 209     if (!named_timer) {
 210         named_timer = g_new0(AnnounceTimer, 1);
 211         g_datalist_set_data(&named_timers, params->id, named_timer);
 212     }
 213
 214     qemu_announce_self(named_timer, params);
 215 }