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Issue #430: Record and guard UDP max payload size with servers.

This commit is contained in:
Willem Toorop 2020-02-13 17:02:24 +01:00
parent 971c43c659
commit 6cb15939ba
2 changed files with 29 additions and 2 deletions
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5
ChangeLog
View File

@ -1,6 +1,7 @@
* 2020-02-??: Versopm 1.6.0 * 2020-02-??: Versopm 1.6.0
* answer_ipv4_address and answer_ipv6_address in reply and response * Issue #432: answer_ipv4_address and answer_ipv6_address in reply
dicts. and response dicts.
* Issue #430: Record and guard UDP max payload size with servers.
* 2019-12-20: Version 1.6.0-beta.1 * 2019-12-20: Version 1.6.0-beta.1
* Migration of build system to cmake. Build now works on Ubuntu, * Migration of build system to cmake. Build now works on Ubuntu,

26
src/server.c
View File

@ -102,6 +102,8 @@ struct connection {
struct sockaddr_storage remote_in; struct sockaddr_storage remote_in;
socklen_t addrlen; socklen_t addrlen;
size_t max_udp_size;
connection *next; connection *next;
connection **prev_next; connection **prev_next;
}; };
@ -326,6 +328,17 @@ getdns_reply(getdns_context *context,
else if (conn->l->transport == GETDNS_TRANSPORT_UDP) { else if (conn->l->transport == GETDNS_TRANSPORT_UDP) {
listener *l = conn->l; listener *l = conn->l;
if (len > conn->max_udp_size) {
_getdns_rr_iter qi_spc, *qi;
(void)memset(buf + 6, 0, 6);
GLDNS_TC_SET(buf);
if ((qi = _getdns_rr_iter_init(&qi_spc, buf, len))) {
DEBUG_SERVER("Truncating reply to: %d\n",
(int)(qi->nxt - buf));
len = qi->nxt - buf;
}
}
if (conn->l->fd >= 0 && sendto(conn->l->fd, (void *)buf, len, 0, if (conn->l->fd >= 0 && sendto(conn->l->fd, (void *)buf, len, 0,
(struct sockaddr *)&conn->remote_in, conn->addrlen) == -1) { (struct sockaddr *)&conn->remote_in, conn->addrlen) == -1) {
/* TODO: handle _getdns_socketerror_wants_retry() */ /* TODO: handle _getdns_socketerror_wants_retry() */
@ -545,6 +558,7 @@ static void tcp_accept_cb(void *userarg)
return; return;
(void) memset(conn, 0, sizeof(tcp_connection)); (void) memset(conn, 0, sizeof(tcp_connection));
conn->super.max_udp_size = 65536;
conn->super.l = l; conn->super.l = l;
conn->super.addrlen = sizeof(conn->super.remote_in); conn->super.addrlen = sizeof(conn->super.remote_in);
if ((conn->fd = accept(l->fd, (struct sockaddr *) if ((conn->fd = accept(l->fd, (struct sockaddr *)
@ -629,6 +643,7 @@ static void udp_read_cb(void *userarg)
conn->l = l; conn->l = l;
conn->addrlen = sizeof(conn->remote_in); conn->addrlen = sizeof(conn->remote_in);
conn->max_udp_size = 512;
if ((len = recvfrom(l->fd, (void *)buf, sizeof(buf), 0, if ((len = recvfrom(l->fd, (void *)buf, sizeof(buf), 0,
(struct sockaddr *)&conn->remote_in, &conn->addrlen)) == -1) { (struct sockaddr *)&conn->remote_in, &conn->addrlen)) == -1) {
if ( _getdns_socketerror_wants_retry() && if ( _getdns_socketerror_wants_retry() &&
@ -713,6 +728,8 @@ static void udp_read_cb(void *userarg)
; /* FROMERR on input, ignore */ ; /* FROMERR on input, ignore */
else { else {
uint32_t max_udp_size = 512;
/* Insert connection */ /* Insert connection */
conn->super.key = conn; conn->super.key = conn;
if (!_getdns_rbtree_insert( if (!_getdns_rbtree_insert(
@ -723,6 +740,15 @@ static void udp_read_cb(void *userarg)
} }
DEBUG_SERVER("[connection add] count: %d\n", DEBUG_SERVER("[connection add] count: %d\n",
(int)l->set->connections_set.count); (int)l->set->connections_set.count);
if (!getdns_dict_get_int(request_dict,
"/additional/0/udp_payload_size", &max_udp_size))
conn->max_udp_size = max_udp_size;
else if (!getdns_dict_get_int(request_dict,
"/additional/1/udp_payload_size", &max_udp_size))
conn->max_udp_size = max_udp_size;
if ((conn->next = l->connections)) if ((conn->next = l->connections))
conn->next->prev_next = &conn->next; conn->next->prev_next = &conn->next;
conn->prev_next = &l->connections; conn->prev_next = &l->connections;