mirror of
https://github.com/lwip-tcpip/lwip.git
synced 2024-08-24 07:05:56 +00:00
MDNS send probes to verify domain before use
This commit is contained in:
Jens Nielsen
Erik Ekman
parent
6706b3778e
commit
d6e58d02a6
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@ -13,7 +13,7 @@
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* Things left to implement:
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* -------------------------
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*
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* - Probing/conflict resolution
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* - Tiebreaking for simultaneous probing
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* - Sending goodbye messages (zero ttl) - shutdown, DHCP lease about to expire, DHCP turned off...
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* - Checking that source address of unicast requests are on the same network
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* - Limiting multicast responses to 1 per second per resource record
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@ -63,6 +63,7 @@
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#include "lwip/mem.h"
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#include "lwip/prot/dns.h"
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#include "lwip/prot/iana.h"
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#include "lwip/timeouts.h"
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#include <string.h>
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@ -135,6 +136,12 @@ NETIF_DECLARE_EXT_CALLBACK(netif_callback)
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/* Lookup for text info on service instance */
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#define REPLY_SERVICE_TXT 0x80
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typedef enum {
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MDNS_PROBING_NOT_STARTED,
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MDNS_PROBING_ONGOING,
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MDNS_PROBING_COMPLETE,
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} mdns_probing_state;
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static const char *dnssd_protos[] = {
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"_udp", /* DNSSD_PROTO_UDP */
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"_tcp", /* DNSSD_PROTO_TCP */
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@ -168,6 +175,10 @@ struct mdns_host {
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struct mdns_service *services[MDNS_MAX_SERVICES];
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/** TTL in seconds of A/AAAA/PTR replies */
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u32_t dns_ttl;
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/** Number of probes sent for the current name */
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u8_t probes_sent;
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/** State in probing sequence */
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mdns_probing_state probing_state;
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};
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/** Information about received packet */
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@ -191,7 +202,7 @@ struct mdns_packet {
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/** Number of unparsed questions */
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u16_t questions_left;
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/** Number of answers in packet,
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* (sum of normal, authorative and additional answers)
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* (sum of normal, authoritative and additional answers)
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* read from packet header */
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u16_t answers;
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/** Number of unparsed answers */
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@ -215,6 +226,8 @@ struct mdns_outpacket {
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u16_t questions;
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/** Number of normal answers written */
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u16_t answers;
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/** Number of authoritative answers written */
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u16_t authoritative;
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/** Number of additional answers written */
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u16_t additional;
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/** Offsets for written domain names in packet.
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@ -261,6 +274,9 @@ struct mdns_answer {
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u16_t rd_offset;
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};
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static err_t mdns_send_outpacket(struct mdns_outpacket *outpkt, u8_t flags);
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static void mdns_probe(void* arg);
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static err_t
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mdns_domain_add_label_base(struct mdns_domain *domain, u8_t len)
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{
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@ -1279,11 +1295,11 @@ mdns_init_outpacket(struct mdns_outpacket *out, struct mdns_packet *in)
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* Add additional answers based on the selected answers
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* Send the packet
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*/
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static void
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mdns_send_outpacket(struct mdns_outpacket *outpkt)
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static err_t
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mdns_send_outpacket(struct mdns_outpacket *outpkt, u8_t flags)
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{
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struct mdns_service *service;
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err_t res;
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err_t res = ERR_ARG;
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int i;
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struct mdns_host *mdns = NETIF_TO_HOST(outpkt->netif);
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@ -1439,13 +1455,12 @@ mdns_send_outpacket(struct mdns_outpacket *outpkt)
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/* Write header */
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memset(&hdr, 0, sizeof(hdr));
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hdr.flags1 = DNS_FLAG1_RESPONSE | DNS_FLAG1_AUTHORATIVE;
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hdr.flags1 = flags;
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hdr.numquestions = lwip_htons(outpkt->questions);
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hdr.numanswers = lwip_htons(outpkt->answers);
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hdr.numauthrr = lwip_htons(outpkt->authoritative);
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hdr.numextrarr = lwip_htons(outpkt->additional);
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if (outpkt->legacy_query) {
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hdr.numquestions = lwip_htons(1);
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hdr.id = lwip_htons(outpkt->tx_id);
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}
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hdr.id = lwip_htons(outpkt->tx_id);
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pbuf_take(outpkt->pbuf, &hdr, sizeof(hdr));
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/* Shrink packet */
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@ -1463,9 +1478,9 @@ mdns_send_outpacket(struct mdns_outpacket *outpkt)
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/* Send created packet */
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LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Sending packet, len=%d, unicast=%d\n", outpkt->write_offset, outpkt->unicast_reply));
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if (outpkt->unicast_reply) {
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udp_sendto_if(mdns_pcb, outpkt->pbuf, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif);
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res = udp_sendto_if(mdns_pcb, outpkt->pbuf, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif);
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} else {
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udp_sendto_if(mdns_pcb, outpkt->pbuf, mcast_destaddr, LWIP_IANA_PORT_MDNS, outpkt->netif);
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res = udp_sendto_if(mdns_pcb, outpkt->pbuf, mcast_destaddr, LWIP_IANA_PORT_MDNS, outpkt->netif);
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}
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}
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@ -1474,8 +1489,10 @@ cleanup:
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pbuf_free(outpkt->pbuf);
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outpkt->pbuf = NULL;
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}
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return res;
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}
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/**
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* Send unsolicited answer containing all our known data
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* @param netif The network interface to send on
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@ -1515,7 +1532,7 @@ mdns_announce(struct netif *netif, const ip_addr_t *destination)
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announce.dest_port = LWIP_IANA_PORT_MDNS;
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SMEMCPY(&announce.dest_addr, destination, sizeof(announce.dest_addr));
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mdns_send_outpacket(&announce);
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mdns_send_outpacket(&announce, DNS_FLAG1_RESPONSE | DNS_FLAG1_AUTHORATIVE);
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}
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/**
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@ -1534,6 +1551,12 @@ mdns_handle_question(struct mdns_packet *pkt)
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err_t res;
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struct mdns_host *mdns = NETIF_TO_HOST(pkt->netif);
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if (mdns->probing_state != MDNS_PROBING_COMPLETE) {
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/* Don't answer questions until we've verified our domains via probing */
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/* todo we should check incoming questions during probing for tiebreaking */
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return;
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}
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mdns_init_outpacket(&reply, pkt);
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while (pkt->questions_left) {
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@ -1569,6 +1592,7 @@ mdns_handle_question(struct mdns_packet *pkt)
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if (replies && reply.legacy_query) {
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/* Add question to reply packet (legacy packet only has 1 question) */
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res = mdns_add_question(&reply, &q.info.domain, q.info.type, q.info.klass, 0);
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reply.questions = 1;
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if (res != ERR_OK) {
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goto cleanup;
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}
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@ -1724,7 +1748,7 @@ mdns_handle_question(struct mdns_packet *pkt)
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}
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}
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mdns_send_outpacket(&reply);
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mdns_send_outpacket(&reply, DNS_FLAG1_RESPONSE | DNS_FLAG1_AUTHORATIVE);
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cleanup:
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if (reply.pbuf) {
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@ -1741,6 +1765,8 @@ cleanup:
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static void
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mdns_handle_response(struct mdns_packet *pkt)
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{
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struct mdns_host* mdns = NETIF_TO_HOST(pkt->netif);
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/* Ignore all questions */
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while (pkt->questions_left) {
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struct mdns_question q;
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@ -1766,6 +1792,36 @@ mdns_handle_response(struct mdns_packet *pkt)
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LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Answer for domain "));
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mdns_domain_debug_print(&ans.info.domain);
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LWIP_DEBUGF(MDNS_DEBUG, (" type %d class %d\n", ans.info.type, ans.info.klass));
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/*"Apparently conflicting Multicast DNS responses received *before* the first probe packet is sent MUST
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be silently ignored" so drop answer if we haven't started probing yet*/
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if (mdns->probing_state == MDNS_PROBING_ONGOING && mdns->probes_sent > 0) {
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struct mdns_domain domain;
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u8_t i;
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u8_t conflict = 0;
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res = mdns_build_host_domain(&domain, mdns);
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if (res == ERR_OK && mdns_domain_eq(&ans.info.domain, &domain)) {
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LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Probe response matches host domain!"));
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conflict = 1;
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}
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for (i = 0; i < MDNS_MAX_SERVICES; ++i) {
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struct mdns_service* service = mdns->services[i];
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if (!service) {
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continue;
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}
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res = mdns_build_service_domain(&domain, service, 1);
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if (res == ERR_OK && mdns_domain_eq(&ans.info.domain, &domain)) {
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LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Probe response matches service domain!"));
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conflict = 1;
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}
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}
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if (conflict != 0) {
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sys_untimeout(mdns_probe, pkt->netif);
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}
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}
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}
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}
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@ -1852,13 +1908,13 @@ mdns_netif_ext_status_callback(struct netif *netif, netif_nsc_reason_t reason, c
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switch (reason) {
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case LWIP_NSC_STATUS_CHANGED:
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if (args->status_changed.state != 0) {
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mdns_resp_announce(netif);
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mdns_resp_restart(netif);
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}
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/* TODO: send goodbye message */
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break;
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case LWIP_NSC_LINK_CHANGED:
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if (args->link_changed.state != 0) {
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mdns_resp_announce(netif);
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mdns_resp_restart(netif);
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}
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break;
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case LWIP_NSC_IPV4_ADDRESS_CHANGED: /* fall through */
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@ -1875,6 +1931,83 @@ mdns_netif_ext_status_callback(struct netif *netif, netif_nsc_reason_t reason, c
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}
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#endif
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static err_t
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mdns_send_probe(struct netif* netif, const ip_addr_t *destination)
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{
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struct mdns_host* mdns;
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struct mdns_outpacket pkt;
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struct mdns_domain domain;
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u8_t i;
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err_t res;
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mdns = NETIF_TO_HOST(netif);
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memset(&pkt, 0, sizeof(pkt));
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pkt.netif = netif;
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/* Add unicast questions with rtype ANY for all our desired records */
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mdns_build_host_domain(&domain, mdns);
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res = mdns_add_question(&pkt, &domain, DNS_RRTYPE_ANY, DNS_RRCLASS_IN, 1);
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if (res != ERR_OK) {
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goto cleanup;
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}
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pkt.questions++;
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for (i = 0; i < MDNS_MAX_SERVICES; ++i) {
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struct mdns_service* service = mdns->services[i];
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if (!service) {
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continue;
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}
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mdns_build_service_domain(&domain, service, 1);
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res = mdns_add_question(&pkt, &domain, DNS_RRTYPE_ANY, DNS_RRCLASS_IN, 1);
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if (res != ERR_OK) {
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goto cleanup;
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}
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pkt.questions++;
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}
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pkt.tx_id = 0;
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SMEMCPY(&pkt.dest_addr, destination, sizeof(pkt.dest_addr));
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res = mdns_send_outpacket(&pkt, 0);
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cleanup:
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if (pkt.pbuf) {
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pbuf_free(pkt.pbuf);
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pkt.pbuf = NULL;
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}
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return res;
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}
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/**
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* Timer callback for probing network.
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*/
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static void
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mdns_probe(void* arg)
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{
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struct netif *netif = (struct netif *)arg;
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struct mdns_host* mdns = NETIF_TO_HOST(netif);
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if(mdns->probes_sent >= 3) {
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/* probing successful, announce the new name */
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mdns->probing_state = MDNS_PROBING_COMPLETE;
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mdns_resp_announce(netif);
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} else {
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#if LWIP_IPV4
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/*if ipv4 wait with probing until address is set*/
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if (!ip4_addr_isany_val(*netif_ip4_addr(netif)) &&
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mdns_send_probe(netif, IP4_ADDR_ANY) == ERR_OK)
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#endif
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{
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#if LWIP_IPV6
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if (mdns_send_probe(netif, IP6_ADDR_ANY) == ERR_OK)
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#endif
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{
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mdns->probes_sent++;
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}
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}
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sys_timeout(250, mdns_probe, netif);
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}
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}
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/**
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* @ingroup mdns
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* Activate MDNS responder for a network interface and send announce packets.
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@ -1904,6 +2037,8 @@ mdns_resp_add_netif(struct netif *netif, const char *hostname, u32_t dns_ttl)
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MEMCPY(&mdns->name, hostname, LWIP_MIN(MDNS_LABEL_MAXLEN, strlen(hostname)));
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mdns->dns_ttl = dns_ttl;
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mdns->probes_sent = 0;
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mdns->probing_state = MDNS_PROBING_NOT_STARTED;
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/* Join multicast groups */
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#if LWIP_IPV4
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@ -1945,6 +2080,10 @@ mdns_resp_remove_netif(struct netif *netif)
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mdns = NETIF_TO_HOST(netif);
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LWIP_ERROR("mdns_resp_remove_netif: Not an active netif", (mdns != NULL), return ERR_VAL);
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if (mdns->probing_state == MDNS_PROBING_ONGOING) {
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sys_untimeout(mdns_probe, netif);
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}
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for (i = 0; i < MDNS_MAX_SERVICES; i++) {
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struct mdns_service *service = mdns->services[i];
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if (service) {
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@ -2073,22 +2212,76 @@ mdns_resp_add_service_txtitem(struct mdns_service *service, const char *txt, u8_
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void
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mdns_resp_announce(struct netif *netif)
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{
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struct mdns_host* mdns = NETIF_TO_HOST(netif);
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LWIP_ASSERT_CORE_LOCKED();
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LWIP_ERROR("mdns_resp_announce: netif != NULL", (netif != NULL), return);
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if (NETIF_TO_HOST(netif) == NULL) {
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if (mdns == NULL) {
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return;
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}
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/* Announce on IPv6 and IPv4 */
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if (mdns->probing_state == MDNS_PROBING_COMPLETE)
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{
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/* Announce on IPv6 and IPv4 */
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#if LWIP_IPV6
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mdns_announce(netif, IP6_ADDR_ANY);
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mdns_announce(netif, IP6_ADDR_ANY);
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#endif
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#if LWIP_IPV4
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if (!ip4_addr_isany_val(*netif_ip4_addr(netif))) {
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mdns_announce(netif, IP4_ADDR_ANY);
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}
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if (!ip4_addr_isany_val(*netif_ip4_addr(netif))) {
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mdns_announce(netif, IP4_ADDR_ANY);
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}
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#endif
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} /* else: ip address changed while probing was ongoing? todo reset counter to restart? */
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}
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/**
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* @ingroup mdns
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* Start mdns responder. Call this when netif and all services are set up, and when cable is
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* connected after being disconnected or administrative interface is set up after being down
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* @param netif The network interface to send on
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*/
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void
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mdns_resp_start(struct netif *netif)
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{
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struct mdns_host* mdns = NETIF_TO_HOST(netif);
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LWIP_ASSERT_CORE_LOCKED();
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LWIP_ERROR("mdns_resp_start: netif != NULL", (netif != NULL), return);
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if (mdns == NULL) {
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return;
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}
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/*todo first probe timeout should be random 0-250 ms*/
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/*todo if we've failed 15 times within a 10 second period we should wait 5 seconds (or wait 5 seconds every time except first)*/
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mdns->probes_sent = 0;
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mdns->probing_state = MDNS_PROBING_ONGOING;
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sys_timeout(250, mdns_probe, netif);
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}
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/**
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* @ingroup mdns
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* Restart mdns responder. Call this when cable is connected after being disconnected or
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* administrative interface is set up after being down
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* @param netif The network interface to send on
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*/
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void
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mdns_resp_restart(struct netif *netif)
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{
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struct mdns_host* mdns = NETIF_TO_HOST(netif);
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LWIP_ASSERT_CORE_LOCKED();
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LWIP_ERROR("mdns_resp_start: netif != NULL", (netif != NULL), return);
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if (mdns == NULL) {
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return;
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}
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/* don't restart unless user called mdns_resp_start already */
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if (mdns->probing_state != MDNS_PROBING_NOT_STARTED) {
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if (mdns->probing_state == MDNS_PROBING_ONGOING) {
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sys_untimeout(mdns_probe, netif);
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}
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mdns_resp_start(netif);
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}
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}
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/**
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@ -66,6 +66,8 @@ err_t mdns_resp_del_service(struct netif *netif, s8_t slot);
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err_t mdns_resp_add_service_txtitem(struct mdns_service *service, const char *txt, u8_t txt_len);
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void mdns_resp_start(struct netif *netif);
|
||||
void mdns_resp_restart(struct netif *netif);
|
||||
void mdns_resp_announce(struct netif *netif);
|
||||
|
||||
/**
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user