node/tender.c

   1 #include <stdio.h>
   2 #include "node.h"
   3
   4 #include <avahi-client/client.h>
   5 #include <avahi-client/publish.h>
   6 #include <avahi-client/lookup.h>
   7
   8 #include <avahi-common/alternative.h>
   9 #include <avahi-common/simple-watch.h>
  10 #include <avahi-common/malloc.h>
  11 #include <avahi-common/error.h>
  12 #include <avahi-common/timeval.h>
  13
  14
  15 #include <libvirt/libvirt.h>
  16
  17 static int accept_tender(const char *name, unsigned long memory, AvahiClient *c) {
  18     OFFER * offer_new;
  19     char domain[254];
  20     if ((offer_new = (OFFER *) malloc(sizeof(OFFER))) == NULL) {
  21         return -1;
  22     }
  23     snprintf(domain, 254, "%s.%s", name, avahi_client_get_host_name_fqdn(c));
  24     offer_new->name = strdup(name);
  25     offer_new->memory = memory;
  26     offer_new->reservate = 1;
  27     offer_new->cost = 0.0f;
  28     reservate =+ memory;
  29     offer_new->group = avahi_entry_group_new(c, entry_group_callback, NULL);
  30     offer_new->next = NULL;
  31
  32     /* TODO: enable givemetake only after domains are migrated! */
  33     avahi_entry_group_add_service(offer_new->group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, domain, "_tender._tcp", NULL, NULL, 651, "givemetake=1", NULL, NULL);
  34     avahi_entry_group_commit(offer_new->group);
  35
  36     if (!offers_head)
  37         offers_head = offer_new;
  38     else
  39         offers_tail->next = offer_new;
  40
  41     offers_tail = offer_new;
  42
  43     return 0;
  44 }
  45
  46 static int offer_tender(const char *name, unsigned long memory, AvahiClient *c) {
  47     OFFER * offer_new;
  48     virConnectPtr conn = NULL; /* the hypervisor connection */
  49
  50     unsigned long long free_memory;
  51     char domain[254], txt[254];
  52
  53     /* NULL means connect to local Xen hypervisor */
  54     conn = virConnectOpenReadOnly(NULL);
  55     if (conn == NULL) {
  56         fprintf(stderr, "Failed to connect to hypervisor\n");
  57         return -1;
  58     }
  59
  60     free_memory = virNodeGetFreeMemory(conn) - reservate;
  61     virConnectClose(conn);
  62
  63     if ((offer_new = (OFFER *) malloc(sizeof(OFFER))) == NULL) {
  64         return -1;
  65     }
  66
  67     offer_new->cost = (float)memory / (float)free_memory;
  68     snprintf(domain, 254, "%s.%s", name, avahi_client_get_host_name_fqdn(c));
  69     snprintf(txt, 254, "cost=%f", offer_new->cost);
  70
  71     printf("Puts hand up: %f\n", offer_new->cost);
  72
  73     /* Here we assume that Avahi will guarantee uniqueness */
  74     offer_new->name = strdup(name);
  75     offer_new->memory = memory;
  76     offer_new->reservate = 0;
  77     offer_new->group = avahi_entry_group_new(c, entry_group_callback, NULL);
  78     offer_new->next = NULL;
  79     avahi_entry_group_add_service(offer_new->group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, domain, "_tender._tcp", NULL, NULL, 651, txt, NULL, NULL);
  80     avahi_entry_group_commit(offer_new->group);
  81
  82
  83     if (!offers_head)
  84         offers_head = offer_new;
  85     else
  86         offers_tail->next = offer_new;
  87
  88     offers_tail = offer_new;
  89
  90     return 0;
  91 }
  92
  93
  94 int pull_tender(const char *name) {
  95     OFFER *offer_prev = NULL;
  96     OFFER *offer_find = offers_head;
  97
  98     while (offer_find) {
  99         if (strcmp(offer_find->name, name) == 0) {
 100             if (offer_find->reservate == 1) reservate =- offer_find->memory;
 101             free(offer_find->name);
 102             avahi_entry_group_free(offer_find->group);
 103             if (!offer_prev)
 104                 offers_head = offer_find->next;
 105             else
 106                 offer_prev->next = offer_find->next;
 107
 108             free(offer_find);
 109             return 0;
 110         } else {
 111             offer_prev = offer_find;
 112             offer_find = offer_find->next;
 113         }
 114     }
 115     return -1;
 116 }
 117
 118 void parse_tender(AvahiServiceResolver *r, const char *name, AvahiStringList *txt) {
 119     AvahiStringList *needle;
 120     if ((needle = avahi_string_list_find (txt, "memory")) != NULL) {
 121         unsigned long int amount;
 122         char *memory;
 123         avahi_string_list_get_pair (needle, NULL, &memory, NULL);
 124         amount = strtoul(memory, NULL, 10);
 125
 126         if (errno != ERANGE && amount > 0) {
 127             if ((needle = avahi_string_list_find (txt, "domain")) != NULL) {
 128                 char *winner;
 129                 avahi_string_list_get_pair (needle, NULL, &winner, NULL);
 130
 131                 if (strcmp(winner, avahi_client_get_host_name_fqdn(avahi_service_resolver_get_client(r))) == 0) {
 132                     accept_tender(name, amount, avahi_service_resolver_get_client(r));
 133                 }
 134
 135                 avahi_free(winner);
 136             } else {
 137                 offer_tender(name, amount, avahi_service_resolver_get_client(r));
 138             }
 139         }
 140
 141         avahi_free(memory);
 142     }
 143 }