2 * util/edns.c - handle base EDNS options.
4 * Copyright (c) 2018, NLnet Labs. All rights reserved.
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39 * This file contains functions for base EDNS options.
44 #include "util/config_file.h"
45 #include "util/netevent.h"
46 #include "util/regional.h"
47 #include "util/data/msgparse.h"
48 #include "util/data/msgreply.h"
52 static int edns_keepalive(struct edns_data* edns_out, struct edns_data* edns_in,
53 struct comm_point* c, struct regional* region)
55 if(c->type == comm_udp)
58 /* To respond with a Keepalive option, the client connection
59 * must have received one message with a TCP Keepalive EDNS option,
60 * and that option must have 0 length data. Subsequent messages
61 * sent on that connection will have a TCP Keepalive option.
63 if(c->tcp_keepalive ||
64 edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_KEEPALIVE)) {
65 int keepalive = c->tcp_timeout_msec / 100;
67 data[0] = (uint8_t)((keepalive >> 8) & 0xff);
68 data[1] = (uint8_t)(keepalive & 0xff);
69 if(!edns_opt_list_append(&edns_out->opt_list, LDNS_EDNS_KEEPALIVE,
70 sizeof(data), data, region))
77 int apply_edns_options(struct edns_data* edns_out, struct edns_data* edns_in,
78 struct config_file* cfg, struct comm_point* c, struct regional* region)
80 if(cfg->do_tcp_keepalive &&
81 !edns_keepalive(edns_out, edns_in, c, region))