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 #include <libvirt/libvirt.h>
  15
  16 typedef struct offer OFFER;
  17 struct offer {
  18     char *name;
  19     float cost;
  20     unsigned long memory;
  21     AvahiEntryGroup *group;
  22     short int reservate;
  23     OFFER *next;
  24 };
  25
  26 OFFER *offers_head = NULL;
  27 OFFER *offers_tail = NULL;
  28
  29 unsigned long reservate = 0;
  30
  31 static int accept_tender(const char *name, unsigned long memory, AvahiClient *c) {
  32     OFFER * offer_new;
  33     char domain[254];
  34     if ((offer_new = (OFFER *) malloc(sizeof(OFFER))) == NULL) {
  35         return -1;
  36     }
  37     snprintf(domain, 254, "%s.%s", name, avahi_client_get_host_name_fqdn(c));
  38     offer_new->name = strdup(name);
  39     offer_new->memory = memory;
  40     offer_new->reservate = 1;
  41     offer_new->cost = 0.0f;
  42     reservate =+ memory;
  43     offer_new->group = avahi_entry_group_new(c, entry_group_callback, NULL);
  44     offer_new->next = NULL;
  45
  46     /* TODO: enable givemetake only after domains are migrated! */
  47     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);
  48     avahi_entry_group_commit(offer_new->group);
  49
  50     if (!offers_head)
  51         offers_head = offer_new;
  52     else
  53         offers_tail->next = offer_new;
  54
  55     offers_tail = offer_new;
  56
  57     return 0;
  58 }
  59
  60 static int offer_tender(const char *name, unsigned long memory, AvahiClient *c) {
  61     OFFER * offer_new;
  62     virConnectPtr conn = NULL; /* the hypervisor connection */
  63
  64     unsigned long long free_memory;
  65     char domain[254], txt[254];
  66
  67     /* NULL means connect to local Xen hypervisor */
  68     conn = virConnectOpenReadOnly(NULL);
  69     if (conn == NULL) {
  70         fprintf(stderr, "Failed to connect to hypervisor\n");
  71         return -1;
  72     }
  73
  74     free_memory = virNodeGetFreeMemory(conn) - reservate;
  75     virConnectClose(conn);
  76
  77     if ((offer_new = (OFFER *) malloc(sizeof(OFFER))) == NULL) {
  78         return -1;
  79     }
  80
  81     offer_new->cost = (float)memory / (float)free_memory;
  82     snprintf(domain, 254, "%s.%s", name, avahi_client_get_host_name_fqdn(c));
  83     snprintf(txt, 254, "cost=%f", offer_new->cost);
  84
  85     printf("Puts hand up: %f\n", offer_new->cost);
  86
  87     /* Here we assume that Avahi will guarantee uniqueness */
  88     offer_new->name = strdup(name);
  89     offer_new->memory = memory;
  90     offer_new->reservate = 0;
  91     offer_new->group = avahi_entry_group_new(c, entry_group_callback, NULL);
  92     offer_new->next = NULL;
  93     avahi_entry_group_add_service(offer_new->group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, domain, "_tender._tcp", NULL, NULL, 651, txt, NULL, NULL);
  94     avahi_entry_group_commit(offer_new->group);
  95
  96
  97     if (!offers_head)
  98         offers_head = offer_new;
  99     else
 100         offers_tail->next = offer_new;
 101
 102     offers_tail = offer_new;
 103
 104     return 0;
 105 }
 106
 107
 108 int pull_tender(const char *name) {
 109     OFFER *offer_prev = NULL;
 110     OFFER *offer_find = offers_head;
 111
 112     while (offer_find) {
 113         if (strcmp(offer_find->name, name) == 0) {
 114             if (offer_find->reservate == 1) reservate =- offer_find->memory;
 115             free(offer_find->name);
 116             avahi_entry_group_free(offer_find->group);
 117             if (!offer_prev)
 118                 offers_head = offer_find->next;
 119             else
 120                 offer_prev->next = offer_find->next;
 121
 122             free(offer_find);
 123             return 0;
 124         } else {
 125             offer_prev = offer_find;
 126             offer_find = offer_find->next;
 127         }
 128     }
 129     return -1;
 130 }
 131
 132 void parse_tender(AvahiServiceResolver *r, const char *name, AvahiStringList *txt) {
 133     AvahiStringList *needle;
 134     if ((needle = avahi_string_list_find (txt, "memory")) != NULL) {
 135         unsigned long int amount;
 136         char *memory;
 137         avahi_string_list_get_pair (needle, NULL, &memory, NULL);
 138         amount = strtoul(memory, NULL, 10);
 139
 140         if (errno != ERANGE && amount > 0) {
 141             if ((needle = avahi_string_list_find (txt, "domain")) != NULL) {
 142                 char *winner;
 143                 avahi_string_list_get_pair (needle, NULL, &winner, NULL);
 144
 145                 if (strcmp(winner, avahi_client_get_host_name_fqdn(avahi_service_resolver_get_client(r))) == 0) {
 146                     accept_tender(name, amount, avahi_service_resolver_get_client(r));
 147                 }
 148
 149                 avahi_free(winner);
 150             } else {
 151                 offer_tender(name, amount, avahi_service_resolver_get_client(r));
 152             }
 153         }
 154
 155         avahi_free(memory);
 156     }
 157 }