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/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "crc32.h"
#include "net.h"
#include "imap-keepalive.h"
#include <time.h>
static bool imap_remote_ip_is_usable(const struct ip_addr *ip)
{
unsigned int addr;
if (ip->family == 0)
return FALSE;
if (ip->family == AF_INET) {
#define IP4(a,b,c,d) ((unsigned)(a)<<24|(unsigned)(b)<<16|(unsigned)(c)<<8|(unsigned)(d))
addr = ip->u.ip4.s_addr;
if (addr >= IP4(10,0,0,0) && addr <= IP4(10,255,255,255))
return FALSE; /* 10/8 */
if (addr >= IP4(192,168,0,0) && addr <= IP4(192,168,255,255))
return FALSE; /* 192.168/16 */
if (addr >= IP4(172,16,0,0) && addr <= IP4(172,31,255,255))
return FALSE; /* 172.16/12 */
if (addr >= IP4(127,0,0,0) && addr <= IP4(127,255,255,255))
return FALSE; /* 127/8 */
#undef IP4
}
else if (ip->family == AF_INET6) {
addr = ip->u.ip6.s6_addr[0];
if (addr == 0xfc || addr == 0xfd)
return FALSE; /* fc00::/7 */
}
return TRUE;
}
unsigned int
imap_keepalive_interval_msecs(const char *username, const struct ip_addr *ip,
unsigned int interval_secs)
{
unsigned int client_hash;
client_hash = ip != NULL && imap_remote_ip_is_usable(ip) ?
net_ip_hash(ip) : crc32_str(username);
interval_secs -= (time(NULL) + client_hash) % interval_secs;
return interval_secs * 1000;
}
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