b826ab586c
All our hash functions are based on siphash24(), factor out siphash_init() and siphash24_finalize() and pass the siphash state to the hash functions rather than the hash key. This simplifies the hash functions, and in particular makes composition simpler as calling siphash24_compress() repeatedly on separate chunks of input has the same effect as first concatenating the input and then calling siphash23_compress() on the result.
164 lines
4.6 KiB
C
164 lines
4.6 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "siphash24.h"
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#include "resolved-dns-server.h"
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/* After how much time to repeat classic DNS requests */
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#define DNS_TIMEOUT_MIN_USEC (500 * USEC_PER_MSEC)
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#define DNS_TIMEOUT_MAX_USEC (5 * USEC_PER_SEC)
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int dns_server_new(
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Manager *m,
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DnsServer **ret,
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DnsServerType type,
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Link *l,
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int family,
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const union in_addr_union *in_addr) {
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DnsServer *s, *tail;
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assert(m);
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assert((type == DNS_SERVER_LINK) == !!l);
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assert(in_addr);
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s = new0(DnsServer, 1);
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if (!s)
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return -ENOMEM;
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s->n_ref = 1;
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s->type = type;
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s->family = family;
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s->address = *in_addr;
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s->resend_timeout = DNS_TIMEOUT_MIN_USEC;
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if (type == DNS_SERVER_LINK) {
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LIST_FIND_TAIL(servers, l->dns_servers, tail);
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LIST_INSERT_AFTER(servers, l->dns_servers, tail, s);
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s->link = l;
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} else if (type == DNS_SERVER_SYSTEM) {
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LIST_FIND_TAIL(servers, m->dns_servers, tail);
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LIST_INSERT_AFTER(servers, m->dns_servers, tail, s);
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} else if (type == DNS_SERVER_FALLBACK) {
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LIST_FIND_TAIL(servers, m->fallback_dns_servers, tail);
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LIST_INSERT_AFTER(servers, m->fallback_dns_servers, tail, s);
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} else
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assert_not_reached("Unknown server type");
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s->manager = m;
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/* A new DNS server that isn't fallback is added and the one
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* we used so far was a fallback one? Then let's try to pick
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* the new one */
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if (type != DNS_SERVER_FALLBACK &&
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m->current_dns_server &&
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m->current_dns_server->type == DNS_SERVER_FALLBACK)
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manager_set_dns_server(m, NULL);
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if (ret)
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*ret = s;
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return 0;
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}
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DnsServer* dns_server_ref(DnsServer *s) {
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if (!s)
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return NULL;
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assert(s->n_ref > 0);
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s->n_ref ++;
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return s;
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}
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static DnsServer* dns_server_free(DnsServer *s) {
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if (!s)
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return NULL;
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if (s->link && s->link->current_dns_server == s)
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link_set_dns_server(s->link, NULL);
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if (s->manager && s->manager->current_dns_server == s)
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manager_set_dns_server(s->manager, NULL);
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free(s);
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return NULL;
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}
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DnsServer* dns_server_unref(DnsServer *s) {
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if (!s)
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return NULL;
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assert(s->n_ref > 0);
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if (s->n_ref == 1)
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dns_server_free(s);
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else
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s->n_ref --;
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return NULL;
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}
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void dns_server_packet_received(DnsServer *s, usec_t rtt) {
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assert(s);
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if (rtt > s->max_rtt) {
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s->max_rtt = rtt;
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s->resend_timeout = MIN(MAX(DNS_TIMEOUT_MIN_USEC, s->max_rtt * 2),
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DNS_TIMEOUT_MAX_USEC);
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}
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}
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void dns_server_packet_lost(DnsServer *s, usec_t usec) {
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assert(s);
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if (s->resend_timeout <= usec)
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s->resend_timeout = MIN(s->resend_timeout * 2, DNS_TIMEOUT_MAX_USEC);
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}
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static void dns_server_hash_func(const void *p, struct siphash *state) {
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const DnsServer *s = p;
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assert(s);
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siphash24_compress(&s->family, sizeof(s->family), state);
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siphash24_compress(&s->address, FAMILY_ADDRESS_SIZE(s->family), state);
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}
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static int dns_server_compare_func(const void *a, const void *b) {
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const DnsServer *x = a, *y = b;
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if (x->family < y->family)
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return -1;
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if (x->family > y->family)
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return 1;
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return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
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}
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const struct hash_ops dns_server_hash_ops = {
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.hash = dns_server_hash_func,
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.compare = dns_server_compare_func
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};
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