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addrwatch.c
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addrwatch.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <errno.h>
#include "addrwatch.h"
#include "list.h"
struct AddrItem {
char *addr;
enum {
ST_NULL,
ST_UP,
ST_DOWN
} state;
};
struct AddrWatcher {
int timeout;
list_t *addrs;
addr_watcher_cb_t cb;
void *ud;
int loop;
};
static struct AddrItem * addr_item_create(const char *addr);
static void addr_item_destructor(void *p);
static int addr_item_match_addr(void *p1, void *p2);
int addrwatch(const char *addr)
{
int sock, flags, r;
struct sockaddr_in sa;
r = -1;
if( (sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
goto FIN1;
flags = 1;
if( setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof(int)) == -1 )
goto FIN2;
memset(&sa, 0, sizeof(sa));
sa.sin_family = AF_INET;
if( inet_pton(AF_INET, addr, &sa.sin_addr) != 1 )
goto FIN2;
if( bind(sock, (struct sockaddr *)&sa, sizeof(sa)) == 0 )
r = 1;
else if( errno == EADDRNOTAVAIL )
r = 0;
else
r = -1;
FIN2:
close(sock);
FIN1:
return r;
}
addr_watcher_t * addr_watcher_create(addr_watcher_cb_t cb, void *userdata, int timeout)
{
addr_watcher_t *watcher;
watcher = malloc(sizeof(addr_watcher_t));
memset(watcher, 0, sizeof(*watcher));
watcher->timeout = timeout;
watcher->addrs = list_create();
watcher->cb = cb;
watcher->ud = userdata;
return watcher;
}
void addr_watcher_destroy(addr_watcher_t *watcher)
{
list_destroy(watcher->addrs, addr_item_destructor);
free(watcher);
}
int addr_watcher_add_addr(addr_watcher_t *watcher, const char *addr)
{
struct AddrItem *item;
if( list_find(watcher->addrs, addr_item_match_addr, (void *)addr) == NULL ) {
item = addr_item_create(addr);
list_append(watcher->addrs, item);
}
return list_size(watcher->addrs);
}
int addr_watcher_del_addr(addr_watcher_t *watcher, const char *addr)
{
struct AddrItem *item;
if( (item = list_remove_first_match(watcher->addrs, addr_item_match_addr, (void *)addr)) ) {
addr_item_destructor(item);
}
return list_size(watcher->addrs);
}
int addr_watcher_watch(addr_watcher_t *watcher)
{
struct AddrItem *item;
list_iterator_t *li;
int n = 0, up, state;
for( li = list_first(watcher->addrs) ; li != NULL ; li = list_next(li) ) {
item = (struct AddrItem *)list_iter_value(li);
if( (up = addrwatch(item->addr)) == -1 ) {
return -1;
}
else {
state = up ? ST_UP : ST_DOWN;
if( state != item->state ) {
item->state = state;
watcher->cb(watcher, item->addr, up, watcher->ud);
n++;
}
}
}
return n;
}
int addr_watcher_watchloop(addr_watcher_t *watcher)
{
int total = 0, n;
struct timeval now, next, timeout;
watcher->loop = 1;
gettimeofday(&next, NULL);
while( watcher->loop ) {
gettimeofday(&now, NULL);
if( timercmp(&now, &next, >) ) {
if( (n = addr_watcher_watch(watcher)) == -1 ) {
watcher->loop = 0;
total = -1;
}
else {
total += n;
timeout.tv_sec = watcher->timeout / 1000;
timeout.tv_usec = (watcher->timeout % 1000) * 1000;
timeradd(&now, &timeout, &next);
}
}
if( watcher->loop ) {
gettimeofday(&now, NULL);
if( timercmp(&next, &now, >) ) {
timersub(&next, &now, &timeout);
usleep(timeout.tv_sec*1000000 + timeout.tv_usec);
}
}
}
return total;
}
void addr_watcher_breakloop(addr_watcher_t *watcher)
{
watcher->loop = 0;
}
static struct AddrItem * addr_item_create(const char *addr)
{
struct AddrItem *item;
item = malloc(sizeof(struct AddrItem));
memset(item, 0, sizeof(*item));
item->state = ST_NULL;
item->addr = malloc(strlen(addr)+1);
strcpy(item->addr, addr);
return item;
}
static void addr_item_destructor(void *p)
{
struct AddrItem *item = (struct AddrItem *)p;
free(item->addr);
free(item);
}
static int addr_item_match_addr(void *p1, void *p2)
{
return strcmp(((struct AddrItem *)p1)->addr, (char *)p2) == 0;
}