diff options
Diffstat (limited to 'thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/apps/mdns/mdns.c')
| -rw-r--r-- | thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/apps/mdns/mdns.c | 2028 |
1 files changed, 2028 insertions, 0 deletions
diff --git a/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/apps/mdns/mdns.c b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/apps/mdns/mdns.c new file mode 100644 index 0000000..14334fc --- /dev/null +++ b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/apps/mdns/mdns.c @@ -0,0 +1,2028 @@ +/** + * @file + * MDNS responder implementation + * + * @defgroup mdns MDNS + * @ingroup apps + * + * RFC 6762 - Multicast DNS\n + * RFC 6763 - DNS-Based Service Discovery\n + * + * @verbinclude mdns.txt + * + * Things left to implement: + * ------------------------- + * + * - Probing/conflict resolution + * - Sending goodbye messages (zero ttl) - shutdown, DHCP lease about to expire, DHCP turned off... + * - Checking that source address of unicast requests are on the same network + * - Limiting multicast responses to 1 per second per resource record + * - Fragmenting replies if required + * - Subscribe to netif address/link change events and act on them (currently needs to be done manually) + * - Handling multi-packet known answers + * - Individual known answer detection for all local IPv6 addresses + * - Dynamic size of outgoing packet + */ + +/* + * Copyright (c) 2015 Verisure Innovation AB + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without modification, + * are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT + * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY + * OF SUCH DAMAGE. + * + * This file is part of the lwIP TCP/IP stack. + * + * Author: Erik Ekman <erik@kryo.se> + * + */ + +#include "lwip/apps/mdns.h" +#include "lwip/apps/mdns_priv.h" +#include "lwip/netif.h" +#include "lwip/udp.h" +#include "lwip/ip_addr.h" +#include "lwip/mem.h" +#include "lwip/prot/dns.h" + +#include <string.h> + +#if LWIP_MDNS_RESPONDER + +#if (LWIP_IPV4 && !LWIP_IGMP) + #error "If you want to use MDNS with IPv4, you have to define LWIP_IGMP=1 in your lwipopts.h" +#endif +#if (LWIP_IPV6 && !LWIP_IPV6_MLD) +#error "If you want to use MDNS with IPv6, you have to define LWIP_IPV6_MLD=1 in your lwipopts.h" +#endif +#if (!LWIP_UDP) + #error "If you want to use MDNS, you have to define LWIP_UDP=1 in your lwipopts.h" +#endif + +#if LWIP_IPV4 +#include "lwip/igmp.h" +/* IPv4 multicast group 224.0.0.251 */ +static const ip_addr_t v4group = DNS_MQUERY_IPV4_GROUP_INIT; +#endif + +#if LWIP_IPV6 +#include "lwip/mld6.h" +/* IPv6 multicast group FF02::FB */ +static const ip_addr_t v6group = DNS_MQUERY_IPV6_GROUP_INIT; +#endif + +#define MDNS_PORT 5353 +#define MDNS_TTL 255 + +/* Stored offsets to beginning of domain names + * Used for compression. + */ +#define NUM_DOMAIN_OFFSETS 10 +#define DOMAIN_JUMP_SIZE 2 +#define DOMAIN_JUMP 0xc000 + +static u8_t mdns_netif_client_id; +static struct udp_pcb *mdns_pcb; + +#define NETIF_TO_HOST(netif) (struct mdns_host*)(netif_get_client_data(netif, mdns_netif_client_id)) + +#define TOPDOMAIN_LOCAL "local" + +#define REVERSE_PTR_TOPDOMAIN "arpa" +#define REVERSE_PTR_V4_DOMAIN "in-addr" +#define REVERSE_PTR_V6_DOMAIN "ip6" + +#define SRV_PRIORITY 0 +#define SRV_WEIGHT 0 + +/* Payload size allocated for each outgoing UDP packet */ +#define OUTPACKET_SIZE 500 + +/* Lookup from hostname -> IPv4 */ +#define REPLY_HOST_A 0x01 +/* Lookup from IPv4/v6 -> hostname */ +#define REPLY_HOST_PTR_V4 0x02 +/* Lookup from hostname -> IPv6 */ +#define REPLY_HOST_AAAA 0x04 +/* Lookup from hostname -> IPv6 */ +#define REPLY_HOST_PTR_V6 0x08 + +/* Lookup for service types */ +#define REPLY_SERVICE_TYPE_PTR 0x10 +/* Lookup for instances of service */ +#define REPLY_SERVICE_NAME_PTR 0x20 +/* Lookup for location of service instance */ +#define REPLY_SERVICE_SRV 0x40 +/* Lookup for text info on service instance */ +#define REPLY_SERVICE_TXT 0x80 + +static const char *dnssd_protos[] = { + "_udp", /* DNSSD_PROTO_UDP */ + "_tcp", /* DNSSD_PROTO_TCP */ +}; + +/** Description of a service */ +struct mdns_service { + /** TXT record to answer with */ + struct mdns_domain txtdata; + /** Name of service, like 'myweb' */ + char name[MDNS_LABEL_MAXLEN + 1]; + /** Type of service, like '_http' */ + char service[MDNS_LABEL_MAXLEN + 1]; + /** Callback function and userdata + * to update txtdata buffer */ + service_get_txt_fn_t txt_fn; + void *txt_userdata; + /** TTL in seconds of SRV/TXT replies */ + u32_t dns_ttl; + /** Protocol, TCP or UDP */ + u16_t proto; + /** Port of the service */ + u16_t port; +}; + +/** Description of a host/netif */ +struct mdns_host { + /** Hostname */ + char name[MDNS_LABEL_MAXLEN + 1]; + /** Pointer to services */ + struct mdns_service *services[MDNS_MAX_SERVICES]; + /** TTL in seconds of A/AAAA/PTR replies */ + u32_t dns_ttl; +}; + +/** Information about received packet */ +struct mdns_packet { + /** Sender IP/port */ + ip_addr_t source_addr; + u16_t source_port; + /** If packet was received unicast */ + u16_t recv_unicast; + /** Netif that received the packet */ + struct netif *netif; + /** Packet data */ + struct pbuf *pbuf; + /** Current parsing offset in packet */ + u16_t parse_offset; + /** Identifier. Used in legacy queries */ + u16_t tx_id; + /** Number of questions in packet, + * read from packet header */ + u16_t questions; + /** Number of unparsed questions */ + u16_t questions_left; + /** Number of answers in packet, + * (sum of normal, authorative and additional answers) + * read from packet header */ + u16_t answers; + /** Number of unparsed answers */ + u16_t answers_left; +}; + +/** Information about outgoing packet */ +struct mdns_outpacket { + /** Netif to send the packet on */ + struct netif *netif; + /** Packet data */ + struct pbuf *pbuf; + /** Current write offset in packet */ + u16_t write_offset; + /** Identifier. Used in legacy queries */ + u16_t tx_id; + /** Destination IP/port if sent unicast */ + ip_addr_t dest_addr; + u16_t dest_port; + /** Number of questions written */ + u16_t questions; + /** Number of normal answers written */ + u16_t answers; + /** Number of additional answers written */ + u16_t additional; + /** Offsets for written domain names in packet. + * Used for compression */ + u16_t domain_offsets[NUM_DOMAIN_OFFSETS]; + /** If all answers in packet should set cache_flush bit */ + u8_t cache_flush; + /** If reply should be sent unicast */ + u8_t unicast_reply; + /** If legacy query. (tx_id needed, and write + * question again in reply before answer) */ + u8_t legacy_query; + /* Reply bitmask for host information */ + u8_t host_replies; + /* Bitmask for which reverse IPv6 hosts to answer */ + u8_t host_reverse_v6_replies; + /* Reply bitmask per service */ + u8_t serv_replies[MDNS_MAX_SERVICES]; +}; + +/** Domain, type and class. + * Shared between questions and answers */ +struct mdns_rr_info { + struct mdns_domain domain; + u16_t type; + u16_t klass; +}; + +struct mdns_question { + struct mdns_rr_info info; + /** unicast reply requested */ + u16_t unicast; +}; + +struct mdns_answer { + struct mdns_rr_info info; + /** cache flush command bit */ + u16_t cache_flush; + /* Validity time in seconds */ + u32_t ttl; + /** Length of variable answer */ + u16_t rd_length; + /** Offset of start of variable answer in packet */ + u16_t rd_offset; +}; + +/** + * Add a label part to a domain + * @param domain The domain to add a label to + * @param label The label to add, like <hostname>, 'local', 'com' or '' + * @param len The length of the label + * @return ERR_OK on success, an err_t otherwise if label too long + */ +err_t +mdns_domain_add_label(struct mdns_domain *domain, const char *label, u8_t len) +{ + if (len > MDNS_LABEL_MAXLEN) { + return ERR_VAL; + } + if (len > 0 && (1 + len + domain->length >= MDNS_DOMAIN_MAXLEN)) { + return ERR_VAL; + } + /* Allow only zero marker on last byte */ + if (len == 0 && (1 + domain->length > MDNS_DOMAIN_MAXLEN)) { + return ERR_VAL; + } + domain->name[domain->length] = len; + domain->length++; + if (len) { + MEMCPY(&domain->name[domain->length], label, len); + domain->length += len; + } + return ERR_OK; +} + +/** + * Internal readname function with max 6 levels of recursion following jumps + * while decompressing name + */ +static u16_t +mdns_readname_loop(struct pbuf *p, u16_t offset, struct mdns_domain *domain, unsigned depth) +{ + u8_t c; + + do { + if (depth > 5) { + /* Too many jumps */ + return MDNS_READNAME_ERROR; + } + + c = pbuf_get_at(p, offset); + offset++; + + /* is this a compressed label? */ + if((c & 0xc0) == 0xc0) { + u16_t jumpaddr; + if (offset >= p->tot_len) { + /* Make sure both jump bytes fit in the packet */ + return MDNS_READNAME_ERROR; + } + jumpaddr = (((c & 0x3f) << 8) | (pbuf_get_at(p, offset) & 0xff)); + offset++; + if (jumpaddr >= SIZEOF_DNS_HDR && jumpaddr < p->tot_len) { + u16_t res; + /* Recursive call, maximum depth will be checked */ + res = mdns_readname_loop(p, jumpaddr, domain, depth + 1); + /* Dont return offset since new bytes were not read (jumped to somewhere in packet) */ + if (res == MDNS_READNAME_ERROR) { + return res; + } + } else { + return MDNS_READNAME_ERROR; + } + break; + } + + /* normal label */ + if (c <= MDNS_LABEL_MAXLEN) { + u8_t label[MDNS_LABEL_MAXLEN]; + err_t res; + + if (c + domain->length >= MDNS_DOMAIN_MAXLEN) { + return MDNS_READNAME_ERROR; + } + if (c != 0) { + if (pbuf_copy_partial(p, label, c, offset) != c) { + return MDNS_READNAME_ERROR; + } + offset += c; + } + res = mdns_domain_add_label(domain, (char *) label, c); + if (res != ERR_OK) { + return MDNS_READNAME_ERROR; + } + } else { + /* bad length byte */ + return MDNS_READNAME_ERROR; + } + } while (c != 0); + + return offset; +} + +/** + * Read possibly compressed domain name from packet buffer + * @param p The packet + * @param offset start position of domain name in packet + * @param domain The domain name destination + * @return The new offset after the domain, or MDNS_READNAME_ERROR + * if reading failed + */ +u16_t +mdns_readname(struct pbuf *p, u16_t offset, struct mdns_domain *domain) +{ + memset(domain, 0, sizeof(struct mdns_domain)); + return mdns_readname_loop(p, offset, domain, 0); +} + +/** + * Print domain name to debug output + * @param domain The domain name + */ +static void +mdns_domain_debug_print(struct mdns_domain *domain) +{ + u8_t *src = domain->name; + u8_t i; + + while (*src) { + u8_t label_len = *src; + src++; + for (i = 0; i < label_len; i++) { + LWIP_DEBUGF(MDNS_DEBUG, ("%c", src[i])); + } + src += label_len; + LWIP_DEBUGF(MDNS_DEBUG, (".")); + } +} + +/** + * Return 1 if contents of domains match (case-insensitive) + * @param a Domain name to compare 1 + * @param b Domain name to compare 2 + * @return 1 if domains are equal ignoring case, 0 otherwise + */ +int +mdns_domain_eq(struct mdns_domain *a, struct mdns_domain *b) +{ + u8_t *ptra, *ptrb; + u8_t len; + int res; + + if (a->length != b->length) { + return 0; + } + + ptra = a->name; + ptrb = b->name; + while (*ptra && *ptrb && ptra < &a->name[a->length]) { + if (*ptra != *ptrb) { + return 0; + } + len = *ptra; + ptra++; + ptrb++; + res = lwip_strnicmp((char *) ptra, (char *) ptrb, len); + if (res != 0) { + return 0; + } + ptra += len; + ptrb += len; + } + if (*ptra != *ptrb && ptra < &a->name[a->length]) { + return 0; + } + return 1; +} + +/** + * Call user supplied function to setup TXT data + * @param service The service to build TXT record for + */ +static void +mdns_prepare_txtdata(struct mdns_service *service) +{ + memset(&service->txtdata, 0, sizeof(struct mdns_domain)); + if (service->txt_fn) { + service->txt_fn(service, service->txt_userdata); + } +} + +#if LWIP_IPV4 +/** + * Build domain for reverse lookup of IPv4 address + * like 12.0.168.192.in-addr.arpa. for 192.168.0.12 + * @param domain Where to write the domain name + * @param addr Pointer to an IPv4 address to encode + * @return ERR_OK if domain was written, an err_t otherwise + */ +static err_t +mdns_build_reverse_v4_domain(struct mdns_domain *domain, const ip4_addr_t *addr) +{ + int i; + err_t res; + const u8_t *ptr; + if (!domain || !addr) { + return ERR_ARG; + } + memset(domain, 0, sizeof(struct mdns_domain)); + ptr = (const u8_t *) addr; + for (i = sizeof(ip4_addr_t) - 1; i >= 0; i--) { + char buf[4]; + u8_t val = ptr[i]; + + lwip_itoa(buf, sizeof(buf), val); + res = mdns_domain_add_label(domain, buf, (u8_t)strlen(buf)); + LWIP_ERROR("mdns_build_reverse_v4_domain: Failed to add label", (res == ERR_OK), return res); + } + res = mdns_domain_add_label(domain, REVERSE_PTR_V4_DOMAIN, (u8_t)(sizeof(REVERSE_PTR_V4_DOMAIN)-1)); + LWIP_ERROR("mdns_build_reverse_v4_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, REVERSE_PTR_TOPDOMAIN, (u8_t)(sizeof(REVERSE_PTR_TOPDOMAIN)-1)); + LWIP_ERROR("mdns_build_reverse_v4_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, NULL, 0); + LWIP_ERROR("mdns_build_reverse_v4_domain: Failed to add label", (res == ERR_OK), return res); + + return ERR_OK; +} +#endif + +#if LWIP_IPV6 +/** + * Build domain for reverse lookup of IP address + * like b.a.9.8.7.6.5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa. for 2001:db8::567:89ab + * @param domain Where to write the domain name + * @param addr Pointer to an IPv6 address to encode + * @return ERR_OK if domain was written, an err_t otherwise + */ +static err_t +mdns_build_reverse_v6_domain(struct mdns_domain *domain, const ip6_addr_t *addr) +{ + int i; + err_t res; + const u8_t *ptr; + if (!domain || !addr) { + return ERR_ARG; + } + memset(domain, 0, sizeof(struct mdns_domain)); + ptr = (const u8_t *) addr; + for (i = sizeof(ip6_addr_t) - 1; i >= 0; i--) { + char buf; + u8_t byte = ptr[i]; + int j; + for (j = 0; j < 2; j++) { + if ((byte & 0x0F) < 0xA) { + buf = '0' + (byte & 0x0F); + } else { + buf = 'a' + (byte & 0x0F) - 0xA; + } + res = mdns_domain_add_label(domain, &buf, sizeof(buf)); + LWIP_ERROR("mdns_build_reverse_v6_domain: Failed to add label", (res == ERR_OK), return res); + byte >>= 4; + } + } + res = mdns_domain_add_label(domain, REVERSE_PTR_V6_DOMAIN, (u8_t)(sizeof(REVERSE_PTR_V6_DOMAIN)-1)); + LWIP_ERROR("mdns_build_reverse_v6_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, REVERSE_PTR_TOPDOMAIN, (u8_t)(sizeof(REVERSE_PTR_TOPDOMAIN)-1)); + LWIP_ERROR("mdns_build_reverse_v6_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, NULL, 0); + LWIP_ERROR("mdns_build_reverse_v6_domain: Failed to add label", (res == ERR_OK), return res); + + return ERR_OK; +} +#endif + +/* Add .local. to domain */ +static err_t +mdns_add_dotlocal(struct mdns_domain *domain) +{ + err_t res = mdns_domain_add_label(domain, TOPDOMAIN_LOCAL, (u8_t)(sizeof(TOPDOMAIN_LOCAL)-1)); + LWIP_ERROR("mdns_add_dotlocal: Failed to add label", (res == ERR_OK), return res); + return mdns_domain_add_label(domain, NULL, 0); +} + +/** + * Build the <hostname>.local. domain name + * @param domain Where to write the domain name + * @param mdns TMDNS netif descriptor. + * @return ERR_OK if domain <hostname>.local. was written, an err_t otherwise + */ +static err_t +mdns_build_host_domain(struct mdns_domain *domain, struct mdns_host *mdns) +{ + err_t res; + memset(domain, 0, sizeof(struct mdns_domain)); + LWIP_ERROR("mdns_build_host_domain: mdns != NULL", (mdns != NULL), return ERR_VAL); + res = mdns_domain_add_label(domain, mdns->name, (u8_t)strlen(mdns->name)); + LWIP_ERROR("mdns_build_host_domain: Failed to add label", (res == ERR_OK), return res); + return mdns_add_dotlocal(domain); +} + +/** + * Build the lookup-all-services special DNS-SD domain name + * @param domain Where to write the domain name + * @return ERR_OK if domain _services._dns-sd._udp.local. was written, an err_t otherwise + */ +static err_t +mdns_build_dnssd_domain(struct mdns_domain *domain) +{ + err_t res; + memset(domain, 0, sizeof(struct mdns_domain)); + res = mdns_domain_add_label(domain, "_services", (u8_t)(sizeof("_services")-1)); + LWIP_ERROR("mdns_build_dnssd_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, "_dns-sd", (u8_t)(sizeof("_dns-sd")-1)); + LWIP_ERROR("mdns_build_dnssd_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, dnssd_protos[DNSSD_PROTO_UDP], (u8_t)strlen(dnssd_protos[DNSSD_PROTO_UDP])); + LWIP_ERROR("mdns_build_dnssd_domain: Failed to add label", (res == ERR_OK), return res); + return mdns_add_dotlocal(domain); +} + +/** + * Build domain name for a service + * @param domain Where to write the domain name + * @param service The service struct, containing service name, type and protocol + * @param include_name Whether to include the service name in the domain + * @return ERR_OK if domain was written. If service name is included, + * <name>.<type>.<proto>.local. will be written, otherwise <type>.<proto>.local. + * An err_t is returned on error. + */ +static err_t +mdns_build_service_domain(struct mdns_domain *domain, struct mdns_service *service, int include_name) +{ + err_t res; + memset(domain, 0, sizeof(struct mdns_domain)); + if (include_name) { + res = mdns_domain_add_label(domain, service->name, (u8_t)strlen(service->name)); + LWIP_ERROR("mdns_build_service_domain: Failed to add label", (res == ERR_OK), return res); + } + res = mdns_domain_add_label(domain, service->service, (u8_t)strlen(service->service)); + LWIP_ERROR("mdns_build_service_domain: Failed to add label", (res == ERR_OK), return res); + res = mdns_domain_add_label(domain, dnssd_protos[service->proto], (u8_t)strlen(dnssd_protos[service->proto])); + LWIP_ERROR("mdns_build_service_domain: Failed to add label", (res == ERR_OK), return res); + return mdns_add_dotlocal(domain); +} + +/** + * Check which replies we should send for a host/netif based on question + * @param netif The network interface that received the question + * @param rr Domain/type/class from a question + * @param reverse_v6_reply Bitmask of which IPv6 addresses to send reverse PTRs for + * if reply bit has REPLY_HOST_PTR_V6 set + * @return Bitmask of which replies to send + */ +static int +check_host(struct netif *netif, struct mdns_rr_info *rr, u8_t *reverse_v6_reply) +{ + err_t res; + int replies = 0; + struct mdns_domain mydomain; + + LWIP_UNUSED_ARG(reverse_v6_reply); /* if ipv6 is disabled */ + + if (rr->klass != DNS_RRCLASS_IN && rr->klass != DNS_RRCLASS_ANY) { + /* Invalid class */ + return replies; + } + + /* Handle PTR for our addresses */ + if (rr->type == DNS_RRTYPE_PTR || rr->type == DNS_RRTYPE_ANY) { +#if LWIP_IPV6 + int i; + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i))) { + res = mdns_build_reverse_v6_domain(&mydomain, netif_ip6_addr(netif, i)); + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain)) { + replies |= REPLY_HOST_PTR_V6; + /* Mark which addresses where requested */ + if (reverse_v6_reply) { + *reverse_v6_reply |= (1 << i); + } + } + } + } +#endif +#if LWIP_IPV4 + if (!ip4_addr_isany_val(*netif_ip4_addr(netif))) { + res = mdns_build_reverse_v4_domain(&mydomain, netif_ip4_addr(netif)); + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain)) { + replies |= REPLY_HOST_PTR_V4; + } + } +#endif + } + + res = mdns_build_host_domain(&mydomain, NETIF_TO_HOST(netif)); + /* Handle requests for our hostname */ + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain)) { + /* TODO return NSEC if unsupported protocol requested */ +#if LWIP_IPV4 + if (!ip4_addr_isany_val(*netif_ip4_addr(netif)) + && (rr->type == DNS_RRTYPE_A || rr->type == DNS_RRTYPE_ANY)) { + replies |= REPLY_HOST_A; + } +#endif +#if LWIP_IPV6 + if (rr->type == DNS_RRTYPE_AAAA || rr->type == DNS_RRTYPE_ANY) { + replies |= REPLY_HOST_AAAA; + } +#endif + } + + return replies; +} + +/** + * Check which replies we should send for a service based on question + * @param service A registered MDNS service + * @param rr Domain/type/class from a question + * @return Bitmask of which replies to send + */ +static int +check_service(struct mdns_service *service, struct mdns_rr_info *rr) +{ + err_t res; + int replies = 0; + struct mdns_domain mydomain; + + if (rr->klass != DNS_RRCLASS_IN && rr->klass != DNS_RRCLASS_ANY) { + /* Invalid class */ + return 0; + } + + res = mdns_build_dnssd_domain(&mydomain); + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain) && + (rr->type == DNS_RRTYPE_PTR || rr->type == DNS_RRTYPE_ANY)) { + /* Request for all service types */ + replies |= REPLY_SERVICE_TYPE_PTR; + } + + res = mdns_build_service_domain(&mydomain, service, 0); + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain) && + (rr->type == DNS_RRTYPE_PTR || rr->type == DNS_RRTYPE_ANY)) { + /* Request for the instance of my service */ + replies |= REPLY_SERVICE_NAME_PTR; + } + + res = mdns_build_service_domain(&mydomain, service, 1); + if (res == ERR_OK && mdns_domain_eq(&rr->domain, &mydomain)) { + /* Request for info about my service */ + if (rr->type == DNS_RRTYPE_SRV || rr->type == DNS_RRTYPE_ANY) { + replies |= REPLY_SERVICE_SRV; + } + if (rr->type == DNS_RRTYPE_TXT || rr->type == DNS_RRTYPE_ANY) { + replies |= REPLY_SERVICE_TXT; + } + } + + return replies; +} + +/** + * Return bytes needed to write before jump for best result of compressing supplied domain + * against domain in outpacket starting at specified offset. + * If a match is found, offset is updated to where to jump to + * @param pbuf Pointer to pbuf with the partially constructed DNS packet + * @param offset Start position of a domain written earlier. If this location is suitable + * for compression, the pointer is updated to where in the domain to jump to. + * @param domain The domain to write + * @return Number of bytes to write of the new domain before writing a jump to the offset. + * If compression can not be done against this previous domain name, the full new + * domain length is returned. + */ +u16_t +mdns_compress_domain(struct pbuf *pbuf, u16_t *offset, struct mdns_domain *domain) +{ + struct mdns_domain target; + u16_t target_end; + u8_t target_len; + u8_t writelen = 0; + u8_t *ptr; + if (pbuf == NULL) { + return domain->length; + } + target_end = mdns_readname(pbuf, *offset, &target); + if (target_end == MDNS_READNAME_ERROR) { + return domain->length; + } + target_len = (u8_t)(target_end - *offset); + ptr = domain->name; + while (writelen < domain->length) { + u8_t domainlen = (u8_t)(domain->length - writelen); + u8_t labellen; + if (domainlen <= target.length && domainlen > DOMAIN_JUMP_SIZE) { + /* Compare domains if target is long enough, and we have enough left of the domain */ + u8_t targetpos = (u8_t)(target.length - domainlen); + if ((targetpos + DOMAIN_JUMP_SIZE) >= target_len) { + /* We are checking at or beyond a jump in the original, stop looking */ + break; + } + if (target.length >= domainlen && + memcmp(&domain->name[writelen], &target.name[targetpos], domainlen) == 0) { + *offset += targetpos; + return writelen; + } + } + /* Skip to next label in domain */ + labellen = *ptr; + writelen += 1 + labellen; + ptr += 1 + labellen; + } + /* Nothing found */ + return domain->length; +} + +/** + * Write domain to outpacket. Compression will be attempted, + * unless domain->skip_compression is set. + * @param outpkt The outpacket to write to + * @param domain The domain name to write + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_write_domain(struct mdns_outpacket *outpkt, struct mdns_domain *domain) +{ + int i; + err_t res; + u16_t writelen = domain->length; + u16_t jump_offset = 0; + u16_t jump; + + if (!domain->skip_compression) { + for (i = 0; i < NUM_DOMAIN_OFFSETS; ++i) { + u16_t offset = outpkt->domain_offsets[i]; + if (offset) { + u16_t len = mdns_compress_domain(outpkt->pbuf, &offset, domain); + if (len < writelen) { + writelen = len; + jump_offset = offset; + } + } + } + } + + if (writelen) { + /* Write uncompressed part of name */ + res = pbuf_take_at(outpkt->pbuf, domain->name, writelen, outpkt->write_offset); + if (res != ERR_OK) { + return res; + } + + /* Store offset of this new domain */ + for (i = 0; i < NUM_DOMAIN_OFFSETS; ++i) { + if (outpkt->domain_offsets[i] == 0) { + outpkt->domain_offsets[i] = outpkt->write_offset; + break; + } + } + + outpkt->write_offset += writelen; + } + if (jump_offset) { + /* Write jump */ + jump = lwip_htons(DOMAIN_JUMP | jump_offset); + res = pbuf_take_at(outpkt->pbuf, &jump, DOMAIN_JUMP_SIZE, outpkt->write_offset); + if (res != ERR_OK) { + return res; + } + outpkt->write_offset += DOMAIN_JUMP_SIZE; + } + return ERR_OK; +} + +/** + * Write a question to an outpacket + * A question contains domain, type and class. Since an answer also starts with these fields this function is also + * called from mdns_add_answer(). + * @param outpkt The outpacket to write to + * @param domain The domain name the answer is for + * @param type The DNS type of the answer (like 'AAAA', 'SRV') + * @param klass The DNS type of the answer (like 'IN') + * @param unicast If highest bit in class should be set, to instruct the responder to + * reply with a unicast packet + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_add_question(struct mdns_outpacket *outpkt, struct mdns_domain *domain, u16_t type, u16_t klass, u16_t unicast) +{ + u16_t question_len; + u16_t field16; + err_t res; + + if (!outpkt->pbuf) { + /* If no pbuf is active, allocate one */ + outpkt->pbuf = pbuf_alloc(PBUF_TRANSPORT, OUTPACKET_SIZE, PBUF_RAM); + if (!outpkt->pbuf) { + return ERR_MEM; + } + outpkt->write_offset = SIZEOF_DNS_HDR; + } + + /* Worst case calculation. Domain string might be compressed */ + question_len = domain->length + sizeof(type) + sizeof(klass); + if (outpkt->write_offset + question_len > outpkt->pbuf->tot_len) { + /* No space */ + return ERR_MEM; + } + + /* Write name */ + res = mdns_write_domain(outpkt, domain); + if (res != ERR_OK) { + return res; + } + + /* Write type */ + field16 = lwip_htons(type); + res = pbuf_take_at(outpkt->pbuf, &field16, sizeof(field16), outpkt->write_offset); + if (res != ERR_OK) { + return res; + } + outpkt->write_offset += sizeof(field16); + + /* Write class */ + if (unicast) { + klass |= 0x8000; + } + field16 = lwip_htons(klass); + res = pbuf_take_at(outpkt->pbuf, &field16, sizeof(field16), outpkt->write_offset); + if (res != ERR_OK) { + return res; + } + outpkt->write_offset += sizeof(field16); + + return ERR_OK; +} + +/** + * Write answer to reply packet. + * buf or answer_domain can be null. The rd_length written will be buf_length + + * size of (compressed) domain. Most uses will need either buf or answer_domain, + * special case is SRV that starts with 3 u16 and then a domain name. + * @param reply The outpacket to write to + * @param domain The domain name the answer is for + * @param type The DNS type of the answer (like 'AAAA', 'SRV') + * @param klass The DNS type of the answer (like 'IN') + * @param cache_flush If highest bit in class should be set, to instruct receiver that + * this reply replaces any earlier answer for this domain/type/class + * @param ttl Validity time in seconds to send out for IP address data in DNS replies + * @param buf Pointer to buffer of answer data + * @param buf_length Length of variable data + * @param answer_domain A domain to write after any buffer data as answer + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_add_answer(struct mdns_outpacket *reply, struct mdns_domain *domain, u16_t type, u16_t klass, u16_t cache_flush, + u32_t ttl, const u8_t *buf, size_t buf_length, struct mdns_domain *answer_domain) +{ + u16_t answer_len; + u16_t field16; + u16_t rdlen_offset; + u16_t answer_offset; + u32_t field32; + err_t res; + + if (!reply->pbuf) { + /* If no pbuf is active, allocate one */ + reply->pbuf = pbuf_alloc(PBUF_TRANSPORT, OUTPACKET_SIZE, PBUF_RAM); + if (!reply->pbuf) { + return ERR_MEM; + } + reply->write_offset = SIZEOF_DNS_HDR; + } + + /* Worst case calculation. Domain strings might be compressed */ + answer_len = domain->length + sizeof(type) + sizeof(klass) + sizeof(ttl) + sizeof(field16)/*rd_length*/; + if (buf) { + answer_len += (u16_t)buf_length; + } + if (answer_domain) { + answer_len += answer_domain->length; + } + if (reply->write_offset + answer_len > reply->pbuf->tot_len) { + /* No space */ + return ERR_MEM; + } + + /* Answer starts with same data as question, then more fields */ + mdns_add_question(reply, domain, type, klass, cache_flush); + + /* Write TTL */ + field32 = lwip_htonl(ttl); + res = pbuf_take_at(reply->pbuf, &field32, sizeof(field32), reply->write_offset); + if (res != ERR_OK) { + return res; + } + reply->write_offset += sizeof(field32); + + /* Store offsets and skip forward to the data */ + rdlen_offset = reply->write_offset; + reply->write_offset += sizeof(field16); + answer_offset = reply->write_offset; + + if (buf) { + /* Write static data */ + res = pbuf_take_at(reply->pbuf, buf, (u16_t)buf_length, reply->write_offset); + if (res != ERR_OK) { + return res; + } + reply->write_offset += (u16_t)buf_length; + } + + if (answer_domain) { + /* Write name answer (compressed if possible) */ + res = mdns_write_domain(reply, answer_domain); + if (res != ERR_OK) { + return res; + } + } + + /* Write rd_length after when we know the answer size */ + field16 = lwip_htons(reply->write_offset - answer_offset); + res = pbuf_take_at(reply->pbuf, &field16, sizeof(field16), rdlen_offset); + + return res; +} + +/** + * Helper function for mdns_read_question/mdns_read_answer + * Reads a domain, type and class from the packet + * @param pkt The MDNS packet to read from. The parse_offset field will be + * incremented to point to the next unparsed byte. + * @param info The struct to fill with domain, type and class + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_read_rr_info(struct mdns_packet *pkt, struct mdns_rr_info *info) +{ + u16_t field16, copied; + pkt->parse_offset = mdns_readname(pkt->pbuf, pkt->parse_offset, &info->domain); + if (pkt->parse_offset == MDNS_READNAME_ERROR) { + return ERR_VAL; + } + + copied = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), pkt->parse_offset); + if (copied != sizeof(field16)) { + return ERR_VAL; + } + pkt->parse_offset += copied; + info->type = lwip_ntohs(field16); + + copied = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), pkt->parse_offset); + if (copied != sizeof(field16)) { + return ERR_VAL; + } + pkt->parse_offset += copied; + info->klass = lwip_ntohs(field16); + + return ERR_OK; +} + +/** + * Read a question from the packet. + * All questions have to be read before the answers. + * @param pkt The MDNS packet to read from. The questions_left field will be decremented + * and the parse_offset will be updated. + * @param question The struct to fill with question data + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_read_question(struct mdns_packet *pkt, struct mdns_question *question) +{ + /* Safety check */ + if (pkt->pbuf->tot_len < pkt->parse_offset) { + return ERR_VAL; + } + + if (pkt->questions_left) { + err_t res; + pkt->questions_left--; + + memset(question, 0, sizeof(struct mdns_question)); + res = mdns_read_rr_info(pkt, &question->info); + if (res != ERR_OK) { + return res; + } + + /* Extract unicast flag from class field */ + question->unicast = question->info.klass & 0x8000; + question->info.klass &= 0x7FFF; + + return ERR_OK; + } + return ERR_VAL; +} + +/** + * Read an answer from the packet + * The variable length reply is not copied, its pbuf offset and length is stored instead. + * @param pkt The MDNS packet to read. The answers_left field will be decremented and + * the parse_offset will be updated. + * @param answer The struct to fill with answer data + * @return ERR_OK on success, an err_t otherwise + */ +static err_t +mdns_read_answer(struct mdns_packet *pkt, struct mdns_answer *answer) +{ + /* Read questions first */ + if (pkt->questions_left) { + return ERR_VAL; + } + + /* Safety check */ + if (pkt->pbuf->tot_len < pkt->parse_offset) { + return ERR_VAL; + } + + if (pkt->answers_left) { + u16_t copied, field16; + u32_t ttl; + err_t res; + pkt->answers_left--; + + memset(answer, 0, sizeof(struct mdns_answer)); + res = mdns_read_rr_info(pkt, &answer->info); + if (res != ERR_OK) { + return res; + } + + /* Extract cache_flush flag from class field */ + answer->cache_flush = answer->info.klass & 0x8000; + answer->info.klass &= 0x7FFF; + + copied = pbuf_copy_partial(pkt->pbuf, &ttl, sizeof(ttl), pkt->parse_offset); + if (copied != sizeof(ttl)) { + return ERR_VAL; + } + pkt->parse_offset += copied; + answer->ttl = lwip_ntohl(ttl); + + copied = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), pkt->parse_offset); + if (copied != sizeof(field16)) { + return ERR_VAL; + } + pkt->parse_offset += copied; + answer->rd_length = lwip_ntohs(field16); + + answer->rd_offset = pkt->parse_offset; + pkt->parse_offset += answer->rd_length; + + return ERR_OK; + } + return ERR_VAL; +} + +#if LWIP_IPV4 +/** Write an IPv4 address (A) RR to outpacket */ +static err_t +mdns_add_a_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct netif *netif) +{ + struct mdns_domain host; + mdns_build_host_domain(&host, NETIF_TO_HOST(netif)); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with A record\n")); + return mdns_add_answer(reply, &host, DNS_RRTYPE_A, DNS_RRCLASS_IN, cache_flush, (NETIF_TO_HOST(netif))->dns_ttl, (const u8_t *) netif_ip4_addr(netif), sizeof(ip4_addr_t), NULL); +} + +/** Write a 4.3.2.1.in-addr.arpa -> hostname.local PTR RR to outpacket */ +static err_t +mdns_add_hostv4_ptr_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct netif *netif) +{ + struct mdns_domain host, revhost; + mdns_build_host_domain(&host, NETIF_TO_HOST(netif)); + mdns_build_reverse_v4_domain(&revhost, netif_ip4_addr(netif)); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with v4 PTR record\n")); + return mdns_add_answer(reply, &revhost, DNS_RRTYPE_PTR, DNS_RRCLASS_IN, cache_flush, (NETIF_TO_HOST(netif))->dns_ttl, NULL, 0, &host); +} +#endif + +#if LWIP_IPV6 +/** Write an IPv6 address (AAAA) RR to outpacket */ +static err_t +mdns_add_aaaa_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct netif *netif, int addrindex) +{ + struct mdns_domain host; + mdns_build_host_domain(&host, NETIF_TO_HOST(netif)); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with AAAA record\n")); + return mdns_add_answer(reply, &host, DNS_RRTYPE_AAAA, DNS_RRCLASS_IN, cache_flush, (NETIF_TO_HOST(netif))->dns_ttl, (const u8_t *) netif_ip6_addr(netif, addrindex), sizeof(ip6_addr_t), NULL); +} + +/** Write a x.y.z.ip6.arpa -> hostname.local PTR RR to outpacket */ +static err_t +mdns_add_hostv6_ptr_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct netif *netif, int addrindex) +{ + struct mdns_domain host, revhost; + mdns_build_host_domain(&host, NETIF_TO_HOST(netif)); + mdns_build_reverse_v6_domain(&revhost, netif_ip6_addr(netif, addrindex)); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with v6 PTR record\n")); + return mdns_add_answer(reply, &revhost, DNS_RRTYPE_PTR, DNS_RRCLASS_IN, cache_flush, (NETIF_TO_HOST(netif))->dns_ttl, NULL, 0, &host); +} +#endif + +/** Write an all-services -> servicetype PTR RR to outpacket */ +static err_t +mdns_add_servicetype_ptr_answer(struct mdns_outpacket *reply, struct mdns_service *service) +{ + struct mdns_domain service_type, service_dnssd; + mdns_build_service_domain(&service_type, service, 0); + mdns_build_dnssd_domain(&service_dnssd); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with service type PTR record\n")); + return mdns_add_answer(reply, &service_dnssd, DNS_RRTYPE_PTR, DNS_RRCLASS_IN, 0, service->dns_ttl, NULL, 0, &service_type); +} + +/** Write a servicetype -> servicename PTR RR to outpacket */ +static err_t +mdns_add_servicename_ptr_answer(struct mdns_outpacket *reply, struct mdns_service *service) +{ + struct mdns_domain service_type, service_instance; + mdns_build_service_domain(&service_type, service, 0); + mdns_build_service_domain(&service_instance, service, 1); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with service name PTR record\n")); + return mdns_add_answer(reply, &service_type, DNS_RRTYPE_PTR, DNS_RRCLASS_IN, 0, service->dns_ttl, NULL, 0, &service_instance); +} + +/** Write a SRV RR to outpacket */ +static err_t +mdns_add_srv_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct mdns_host *mdns, struct mdns_service *service) +{ + struct mdns_domain service_instance, srvhost; + u16_t srvdata[3]; + mdns_build_service_domain(&service_instance, service, 1); + mdns_build_host_domain(&srvhost, mdns); + if (reply->legacy_query) { + /* RFC 6762 section 18.14: + * In legacy unicast responses generated to answer legacy queries, + * name compression MUST NOT be performed on SRV records. + */ + srvhost.skip_compression = 1; + } + srvdata[0] = lwip_htons(SRV_PRIORITY); + srvdata[1] = lwip_htons(SRV_WEIGHT); + srvdata[2] = lwip_htons(service->port); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with SRV record\n")); + return mdns_add_answer(reply, &service_instance, DNS_RRTYPE_SRV, DNS_RRCLASS_IN, cache_flush, service->dns_ttl, + (const u8_t *) &srvdata, sizeof(srvdata), &srvhost); +} + +/** Write a TXT RR to outpacket */ +static err_t +mdns_add_txt_answer(struct mdns_outpacket *reply, u16_t cache_flush, struct mdns_service *service) +{ + struct mdns_domain service_instance; + mdns_build_service_domain(&service_instance, service, 1); + mdns_prepare_txtdata(service); + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Responding with TXT record\n")); + return mdns_add_answer(reply, &service_instance, DNS_RRTYPE_TXT, DNS_RRCLASS_IN, cache_flush, service->dns_ttl, + (u8_t *) &service->txtdata.name, service->txtdata.length, NULL); +} + +/** + * Setup outpacket as a reply to the incoming packet + */ +static void +mdns_init_outpacket(struct mdns_outpacket *out, struct mdns_packet *in) +{ + memset(out, 0, sizeof(struct mdns_outpacket)); + out->cache_flush = 1; + out->netif = in->netif; + + /* Copy source IP/port to use when responding unicast, or to choose + * which pcb to use for multicast (IPv4/IPv6) + */ + SMEMCPY(&out->dest_addr, &in->source_addr, sizeof(ip_addr_t)); + out->dest_port = in->source_port; + + if (in->source_port != MDNS_PORT) { + out->unicast_reply = 1; + out->cache_flush = 0; + if (in->questions == 1) { + out->legacy_query = 1; + out->tx_id = in->tx_id; + } + } + + if (in->recv_unicast) { + out->unicast_reply = 1; + } +} + +/** + * Send chosen answers as a reply + * + * Add all selected answers (first write will allocate pbuf) + * Add additional answers based on the selected answers + * Send the packet + */ +static void +mdns_send_outpacket(struct mdns_outpacket *outpkt) +{ + struct mdns_service *service; + err_t res; + int i; + struct mdns_host* mdns = NETIF_TO_HOST(outpkt->netif); + + /* Write answers to host questions */ +#if LWIP_IPV4 + if (outpkt->host_replies & REPLY_HOST_A) { + res = mdns_add_a_answer(outpkt, outpkt->cache_flush, outpkt->netif); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + if (outpkt->host_replies & REPLY_HOST_PTR_V4) { + res = mdns_add_hostv4_ptr_answer(outpkt, outpkt->cache_flush, outpkt->netif); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } +#endif +#if LWIP_IPV6 + if (outpkt->host_replies & REPLY_HOST_AAAA) { + int addrindex; + for (addrindex = 0; addrindex < LWIP_IPV6_NUM_ADDRESSES; ++addrindex) { + if (ip6_addr_isvalid(netif_ip6_addr_state(outpkt->netif, addrindex))) { + res = mdns_add_aaaa_answer(outpkt, outpkt->cache_flush, outpkt->netif, addrindex); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + } + } + if (outpkt->host_replies & REPLY_HOST_PTR_V6) { + u8_t rev_addrs = outpkt->host_reverse_v6_replies; + int addrindex = 0; + while (rev_addrs) { + if (rev_addrs & 1) { + res = mdns_add_hostv6_ptr_answer(outpkt, outpkt->cache_flush, outpkt->netif, addrindex); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + addrindex++; + rev_addrs >>= 1; + } + } +#endif + + /* Write answers to service questions */ + for (i = 0; i < MDNS_MAX_SERVICES; ++i) { + service = mdns->services[i]; + if (!service) { + continue; + } + + if (outpkt->serv_replies[i] & REPLY_SERVICE_TYPE_PTR) { + res = mdns_add_servicetype_ptr_answer(outpkt, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + + if (outpkt->serv_replies[i] & REPLY_SERVICE_NAME_PTR) { + res = mdns_add_servicename_ptr_answer(outpkt, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + + if (outpkt->serv_replies[i] & REPLY_SERVICE_SRV) { + res = mdns_add_srv_answer(outpkt, outpkt->cache_flush, mdns, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + + if (outpkt->serv_replies[i] & REPLY_SERVICE_TXT) { + res = mdns_add_txt_answer(outpkt, outpkt->cache_flush, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->answers++; + } + } + + /* All answers written, add additional RRs */ + for (i = 0; i < MDNS_MAX_SERVICES; ++i) { + service = mdns->services[i]; + if (!service) { + continue; + } + + if (outpkt->serv_replies[i] & REPLY_SERVICE_NAME_PTR) { + /* Our service instance requested, include SRV & TXT + * if they are already not requested. */ + if (!(outpkt->serv_replies[i] & REPLY_SERVICE_SRV)) { + res = mdns_add_srv_answer(outpkt, outpkt->cache_flush, mdns, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->additional++; + } + + if (!(outpkt->serv_replies[i] & REPLY_SERVICE_TXT)) { + res = mdns_add_txt_answer(outpkt, outpkt->cache_flush, service); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->additional++; + } + } + + /* If service instance, SRV, record or an IP address is requested, + * supply all addresses for the host + */ + if ((outpkt->serv_replies[i] & (REPLY_SERVICE_NAME_PTR | REPLY_SERVICE_SRV)) || + (outpkt->host_replies & (REPLY_HOST_A | REPLY_HOST_AAAA))) { +#if LWIP_IPV6 + if (!(outpkt->host_replies & REPLY_HOST_AAAA)) { + int addrindex; + for (addrindex = 0; addrindex < LWIP_IPV6_NUM_ADDRESSES; ++addrindex) { + if (ip6_addr_isvalid(netif_ip6_addr_state(outpkt->netif, addrindex))) { + res = mdns_add_aaaa_answer(outpkt, outpkt->cache_flush, outpkt->netif, addrindex); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->additional++; + } + } + } +#endif +#if LWIP_IPV4 + if (!(outpkt->host_replies & REPLY_HOST_A)) { + res = mdns_add_a_answer(outpkt, outpkt->cache_flush, outpkt->netif); + if (res != ERR_OK) { + goto cleanup; + } + outpkt->additional++; + } +#endif + } + } + + if (outpkt->pbuf) { + const ip_addr_t *mcast_destaddr; + struct dns_hdr hdr; + + /* Write header */ + memset(&hdr, 0, sizeof(hdr)); + hdr.flags1 = DNS_FLAG1_RESPONSE | DNS_FLAG1_AUTHORATIVE; + hdr.numanswers = lwip_htons(outpkt->answers); + hdr.numextrarr = lwip_htons(outpkt->additional); + if (outpkt->legacy_query) { + hdr.numquestions = lwip_htons(1); + hdr.id = lwip_htons(outpkt->tx_id); + } + pbuf_take(outpkt->pbuf, &hdr, sizeof(hdr)); + + /* Shrink packet */ + pbuf_realloc(outpkt->pbuf, outpkt->write_offset); + + if (IP_IS_V6_VAL(outpkt->dest_addr)) { +#if LWIP_IPV6 + mcast_destaddr = &v6group; +#endif + } else { +#if LWIP_IPV4 + mcast_destaddr = &v4group; +#endif + } + /* Send created packet */ + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Sending packet, len=%d, unicast=%d\n", outpkt->write_offset, outpkt->unicast_reply)); + if (outpkt->unicast_reply) { + udp_sendto_if(mdns_pcb, outpkt->pbuf, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif); + } else { + udp_sendto_if(mdns_pcb, outpkt->pbuf, mcast_destaddr, MDNS_PORT, outpkt->netif); + } + } + +cleanup: + if (outpkt->pbuf) { + pbuf_free(outpkt->pbuf); + outpkt->pbuf = NULL; + } +} + +/** + * Send unsolicited answer containing all our known data + * @param netif The network interface to send on + * @param destination The target address to send to (usually multicast address) + */ +static void +mdns_announce(struct netif *netif, const ip_addr_t *destination) +{ + struct mdns_outpacket announce; + int i; + struct mdns_host* mdns = NETIF_TO_HOST(netif); + + memset(&announce, 0, sizeof(announce)); + announce.netif = netif; + announce.cache_flush = 1; +#if LWIP_IPV4 + if (!ip4_addr_isany_val(*netif_ip4_addr(netif))) + announce.host_replies = REPLY_HOST_A | REPLY_HOST_PTR_V4; +#endif +#if LWIP_IPV6 + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) { + if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i))) { + announce.host_replies |= REPLY_HOST_AAAA | REPLY_HOST_PTR_V6; + announce.host_reverse_v6_replies |= (1 << i); + } + } +#endif + + for (i = 0; i < MDNS_MAX_SERVICES; i++) { + struct mdns_service *serv = mdns->services[i]; + if (serv) { + announce.serv_replies[i] = REPLY_SERVICE_TYPE_PTR | REPLY_SERVICE_NAME_PTR | + REPLY_SERVICE_SRV | REPLY_SERVICE_TXT; + } + } + + announce.dest_port = MDNS_PORT; + SMEMCPY(&announce.dest_addr, destination, sizeof(announce.dest_addr)); + mdns_send_outpacket(&announce); +} + +/** + * Handle question MDNS packet + * 1. Parse all questions and set bits what answers to send + * 2. Clear pending answers if known answers are supplied + * 3. Put chosen answers in new packet and send as reply + */ +static void +mdns_handle_question(struct mdns_packet *pkt) +{ + struct mdns_service *service; + struct mdns_outpacket reply; + int replies = 0; + int i; + err_t res; + struct mdns_host* mdns = NETIF_TO_HOST(pkt->netif); + + mdns_init_outpacket(&reply, pkt); + + while (pkt->questions_left) { + struct mdns_question q; + + res = mdns_read_question(pkt, &q); + if (res != ERR_OK) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Failed to parse question, skipping query packet\n")); + return; + } + + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Query for domain ")); + mdns_domain_debug_print(&q.info.domain); + LWIP_DEBUGF(MDNS_DEBUG, (" type %d class %d\n", q.info.type, q.info.klass)); + + if (q.unicast) { + /* Reply unicast if any question is unicast */ + reply.unicast_reply = 1; + } + + reply.host_replies |= check_host(pkt->netif, &q.info, &reply.host_reverse_v6_replies); + replies |= reply.host_replies; + + for (i = 0; i < MDNS_MAX_SERVICES; ++i) { + service = mdns->services[i]; + if (!service) { + continue; + } + reply.serv_replies[i] |= check_service(service, &q.info); + replies |= reply.serv_replies[i]; + } + + if (replies && reply.legacy_query) { + /* Add question to reply packet (legacy packet only has 1 question) */ + res = mdns_add_question(&reply, &q.info.domain, q.info.type, q.info.klass, 0); + if (res != ERR_OK) { + goto cleanup; + } + } + } + + /* Handle known answers */ + while (pkt->answers_left) { + struct mdns_answer ans; + u8_t rev_v6; + int match; + + res = mdns_read_answer(pkt, &ans); + if (res != ERR_OK) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Failed to parse answer, skipping query packet\n")); + goto cleanup; + } + + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Known answer for domain ")); + mdns_domain_debug_print(&ans.info.domain); + LWIP_DEBUGF(MDNS_DEBUG, (" type %d class %d\n", ans.info.type, ans.info.klass)); + + + if (ans.info.type == DNS_RRTYPE_ANY || ans.info.klass == DNS_RRCLASS_ANY) { + /* Skip known answers for ANY type & class */ + continue; + } + + rev_v6 = 0; + match = reply.host_replies & check_host(pkt->netif, &ans.info, &rev_v6); + if (match && (ans.ttl > (mdns->dns_ttl / 2))) { + /* The RR in the known answer matches an RR we are planning to send, + * and the TTL is less than half gone. + * If the payload matches we should not send that answer. + */ + if (ans.info.type == DNS_RRTYPE_PTR) { + /* Read domain and compare */ + struct mdns_domain known_ans, my_ans; + u16_t len; + len = mdns_readname(pkt->pbuf, ans.rd_offset, &known_ans); + res = mdns_build_host_domain(&my_ans, mdns); + if (len != MDNS_READNAME_ERROR && res == ERR_OK && mdns_domain_eq(&known_ans, &my_ans)) { +#if LWIP_IPV4 + if (match & REPLY_HOST_PTR_V4) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: v4 PTR\n")); + reply.host_replies &= ~REPLY_HOST_PTR_V4; + } +#endif +#if LWIP_IPV6 + if (match & REPLY_HOST_PTR_V6) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: v6 PTR\n")); + reply.host_reverse_v6_replies &= ~rev_v6; + if (reply.host_reverse_v6_replies == 0) { + reply.host_replies &= ~REPLY_HOST_PTR_V6; + } + } +#endif + } + } else if (match & REPLY_HOST_A) { +#if LWIP_IPV4 + if (ans.rd_length == sizeof(ip4_addr_t) && + pbuf_memcmp(pkt->pbuf, ans.rd_offset, netif_ip4_addr(pkt->netif), ans.rd_length) == 0) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: A\n")); + reply.host_replies &= ~REPLY_HOST_A; + } +#endif + } else if (match & REPLY_HOST_AAAA) { +#if LWIP_IPV6 + if (ans.rd_length == sizeof(ip6_addr_t) && + /* TODO this clears all AAAA responses if first addr is set as known */ + pbuf_memcmp(pkt->pbuf, ans.rd_offset, netif_ip6_addr(pkt->netif, 0), ans.rd_length) == 0) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: AAAA\n")); + reply.host_replies &= ~REPLY_HOST_AAAA; + } +#endif + } + } + + for (i = 0; i < MDNS_MAX_SERVICES; ++i) { + service = mdns->services[i]; + if (!service) { + continue; + } + match = reply.serv_replies[i] & check_service(service, &ans.info); + if (match && (ans.ttl > (service->dns_ttl / 2))) { + /* The RR in the known answer matches an RR we are planning to send, + * and the TTL is less than half gone. + * If the payload matches we should not send that answer. + */ + if (ans.info.type == DNS_RRTYPE_PTR) { + /* Read domain and compare */ + struct mdns_domain known_ans, my_ans; + u16_t len; + len = mdns_readname(pkt->pbuf, ans.rd_offset, &known_ans); + if (len != MDNS_READNAME_ERROR) { + if (match & REPLY_SERVICE_TYPE_PTR) { + res = mdns_build_service_domain(&my_ans, service, 0); + if (res == ERR_OK && mdns_domain_eq(&known_ans, &my_ans)) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: service type PTR\n")); + reply.serv_replies[i] &= ~REPLY_SERVICE_TYPE_PTR; + } + } + if (match & REPLY_SERVICE_NAME_PTR) { + res = mdns_build_service_domain(&my_ans, service, 1); + if (res == ERR_OK && mdns_domain_eq(&known_ans, &my_ans)) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: service name PTR\n")); + reply.serv_replies[i] &= ~REPLY_SERVICE_NAME_PTR; + } + } + } + } else if (match & REPLY_SERVICE_SRV) { + /* Read and compare to my SRV record */ + u16_t field16, len, read_pos; + struct mdns_domain known_ans, my_ans; + read_pos = ans.rd_offset; + do { + /* Check priority field */ + len = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), read_pos); + if (len != sizeof(field16) || lwip_ntohs(field16) != SRV_PRIORITY) { + break; + } + read_pos += len; + /* Check weight field */ + len = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), read_pos); + if (len != sizeof(field16) || lwip_ntohs(field16) != SRV_WEIGHT) { + break; + } + read_pos += len; + /* Check port field */ + len = pbuf_copy_partial(pkt->pbuf, &field16, sizeof(field16), read_pos); + if (len != sizeof(field16) || lwip_ntohs(field16) != service->port) { + break; + } + read_pos += len; + /* Check host field */ + len = mdns_readname(pkt->pbuf, read_pos, &known_ans); + mdns_build_host_domain(&my_ans, mdns); + if (len == MDNS_READNAME_ERROR || !mdns_domain_eq(&known_ans, &my_ans)) { + break; + } + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: SRV\n")); + reply.serv_replies[i] &= ~REPLY_SERVICE_SRV; + } while (0); + } else if (match & REPLY_SERVICE_TXT) { + mdns_prepare_txtdata(service); + if (service->txtdata.length == ans.rd_length && + pbuf_memcmp(pkt->pbuf, ans.rd_offset, service->txtdata.name, ans.rd_length) == 0) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Skipping known answer: TXT\n")); + reply.serv_replies[i] &= ~REPLY_SERVICE_TXT; + } + } + } + } + } + + mdns_send_outpacket(&reply); + +cleanup: + if (reply.pbuf) { + /* This should only happen if we fail to alloc/write question for legacy query */ + pbuf_free(reply.pbuf); + reply.pbuf = NULL; + } +} + +/** + * Handle response MDNS packet + * Only prints debug for now. Will need more code to do conflict resolution. + */ +static void +mdns_handle_response(struct mdns_packet *pkt) +{ + /* Ignore all questions */ + while (pkt->questions_left) { + struct mdns_question q; + err_t res; + + res = mdns_read_question(pkt, &q); + if (res != ERR_OK) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Failed to parse question, skipping response packet\n")); + return; + } + } + + while (pkt->answers_left) { + struct mdns_answer ans; + err_t res; + + res = mdns_read_answer(pkt, &ans); + if (res != ERR_OK) { + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Failed to parse answer, skipping response packet\n")); + return; + } + + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Answer for domain ")); + mdns_domain_debug_print(&ans.info.domain); + LWIP_DEBUGF(MDNS_DEBUG, (" type %d class %d\n", ans.info.type, ans.info.klass)); + } +} + +/** + * Receive input function for MDNS packets. + * Handles both IPv4 and IPv6 UDP pcbs. + */ +static void +mdns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port) +{ + struct dns_hdr hdr; + struct mdns_packet packet; + struct netif *recv_netif = ip_current_input_netif(); + u16_t offset = 0; + + LWIP_UNUSED_ARG(arg); + LWIP_UNUSED_ARG(pcb); + + LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Received IPv%d MDNS packet, len %d\n", IP_IS_V6(addr)? 6 : 4, p->tot_len)); + + if (NETIF_TO_HOST(recv_netif) == NULL) { + /* From netif not configured for MDNS */ + goto dealloc; + } + + if (pbuf_copy_partial(p, &hdr, SIZEOF_DNS_HDR, offset) < SIZEOF_DNS_HDR) { + /* Too small */ + goto dealloc; + } + offset += SIZEOF_DNS_HDR; + + if (DNS_HDR_GET_OPCODE(&hdr)) { + /* Ignore non-standard queries in multicast packets (RFC 6762, section 18.3) */ + goto dealloc; + } + + memset(&packet, 0, sizeof(packet)); + SMEMCPY(&packet.source_addr, addr, sizeof(packet.source_addr)); + packet.source_port = port; + packet.netif = recv_netif; + packet.pbuf = p; + packet.parse_offset = offset; + packet.tx_id = lwip_ntohs(hdr.id); + packet.questions = packet.questions_left = lwip_ntohs(hdr.numquestions); + packet.answers = packet.answers_left = lwip_ntohs(hdr.numanswers) + lwip_ntohs(hdr.numauthrr) + lwip_ntohs(hdr.numextrarr); + +#if LWIP_IPV6 + if (IP_IS_V6(ip_current_dest_addr())) { + if (!ip_addr_cmp(ip_current_dest_addr(), &v6group)) { + packet.recv_unicast = 1; + } + } +#endif +#if LWIP_IPV4 + if (!IP_IS_V6(ip_current_dest_addr())) { + if (!ip_addr_cmp(ip_current_dest_addr(), &v4group)) { + packet.recv_unicast = 1; + } + } +#endif + + if (hdr.flags1 & DNS_FLAG1_RESPONSE) { + mdns_handle_response(&packet); + } else { + mdns_handle_question(&packet); + } + +dealloc: + pbuf_free(p); +} + +/** + * @ingroup mdns + * Initiate MDNS responder. Will open UDP sockets on port 5353 + */ +void +mdns_resp_init(void) +{ + err_t res; + + mdns_pcb = udp_new_ip_type(IPADDR_TYPE_ANY); + LWIP_ASSERT("Failed to allocate pcb", mdns_pcb != NULL); +#if LWIP_MULTICAST_TX_OPTIONS + udp_set_multicast_ttl(mdns_pcb, MDNS_TTL); +#else + mdns_pcb->ttl = MDNS_TTL; +#endif + res = udp_bind(mdns_pcb, IP_ANY_TYPE, MDNS_PORT); + LWIP_UNUSED_ARG(res); /* in case of LWIP_NOASSERT */ + LWIP_ASSERT("Failed to bind pcb", res == ERR_OK); + udp_recv(mdns_pcb, mdns_recv, NULL); + + mdns_netif_client_id = netif_alloc_client_data_id(); +} + +/** + * @ingroup mdns + * Announce IP settings have changed on netif. + * Call this in your callback registered by netif_set_status_callback(). + * This function may go away in the future when netif supports registering + * multiple callback functions. + * @param netif The network interface where settings have changed. + */ +void +mdns_resp_netif_settings_changed(struct netif *netif) +{ + LWIP_ERROR("mdns_resp_netif_ip_changed: netif != NULL", (netif != NULL), return); + + if (NETIF_TO_HOST(netif) == NULL) { + return; + } + + /* Announce on IPv6 and IPv4 */ +#if LWIP_IPV6 + mdns_announce(netif, IP6_ADDR_ANY); +#endif +#if LWIP_IPV4 + mdns_announce(netif, IP4_ADDR_ANY); +#endif +} + +/** + * @ingroup mdns + * Activate MDNS responder for a network interface and send announce packets. + * @param netif The network interface to activate. + * @param hostname Name to use. Queries for <hostname>.local will be answered + * with the IP addresses of the netif. The hostname will be copied, the + * given pointer can be on the stack. + * @param dns_ttl Validity time in seconds to send out for IP address data in DNS replies + * @return ERR_OK if netif was added, an err_t otherwise + */ +err_t +mdns_resp_add_netif(struct netif *netif, const char *hostname, u32_t dns_ttl) +{ + err_t res; + struct mdns_host* mdns; + + LWIP_ERROR("mdns_resp_add_netif: netif != NULL", (netif != NULL), return ERR_VAL); + LWIP_ERROR("mdns_resp_add_netif: Hostname too long", (strlen(hostname) <= MDNS_LABEL_MAXLEN), return ERR_VAL); + + LWIP_ASSERT("mdns_resp_add_netif: Double add", NETIF_TO_HOST(netif) == NULL); + mdns = (struct mdns_host *) mem_malloc(sizeof(struct mdns_host)); + LWIP_ERROR("mdns_resp_add_netif: Alloc failed", (mdns != NULL), return ERR_MEM); + + netif_set_client_data(netif, mdns_netif_client_id, mdns); + + memset(mdns, 0, sizeof(struct mdns_host)); + MEMCPY(&mdns->name, hostname, LWIP_MIN(MDNS_LABEL_MAXLEN, strlen(hostname))); + mdns->dns_ttl = dns_ttl; + + /* Join multicast groups */ +#if LWIP_IPV4 + res = igmp_joingroup_netif(netif, ip_2_ip4(&v4group)); + if (res != ERR_OK) { + goto cleanup; + } +#endif +#if LWIP_IPV6 + res = mld6_joingroup_netif(netif, ip_2_ip6(&v6group)); + if (res != ERR_OK) { + goto cleanup; + } +#endif + + mdns_resp_netif_settings_changed(netif); + return ERR_OK; + +cleanup: + mem_free(mdns); + netif_set_client_data(netif, mdns_netif_client_id, NULL); + return res; +} + +/** + * @ingroup mdns + * Stop responding to MDNS queries on this interface, leave multicast groups, + * and free the helper structure and any of its services. + * @param netif The network interface to remove. + * @return ERR_OK if netif was removed, an err_t otherwise + */ +err_t +mdns_resp_remove_netif(struct netif *netif) +{ + int i; + struct mdns_host* mdns; + + LWIP_ASSERT("mdns_resp_remove_netif: Null pointer", netif); + mdns = NETIF_TO_HOST(netif); + LWIP_ERROR("mdns_resp_remove_netif: Not an active netif", (mdns != NULL), return ERR_VAL); + + for (i = 0; i < MDNS_MAX_SERVICES; i++) { + struct mdns_service *service = mdns->services[i]; + if (service) { + mem_free(service); + } + } + + /* Leave multicast groups */ +#if LWIP_IPV4 + igmp_leavegroup_netif(netif, ip_2_ip4(&v4group)); +#endif +#if LWIP_IPV6 + mld6_leavegroup_netif(netif, ip_2_ip6(&v6group)); +#endif + + mem_free(mdns); + netif_set_client_data(netif, mdns_netif_client_id, NULL); + return ERR_OK; +} + +/** + * @ingroup mdns + * Add a service to the selected network interface. + * @param netif The network interface to publish this service on + * @param name The name of the service + * @param service The service type, like "_http" + * @param proto The service protocol, DNSSD_PROTO_TCP for TCP ("_tcp") and DNSSD_PROTO_UDP + * for others ("_udp") + * @param port The port the service listens to + * @param dns_ttl Validity time in seconds to send out for service data in DNS replies + * @param txt_fn Callback to get TXT data. Will be called each time a TXT reply is created to + * allow dynamic replies. + * @param txt_data Userdata pointer for txt_fn + * @return ERR_OK if the service was added to the netif, an err_t otherwise + */ +err_t +mdns_resp_add_service(struct netif *netif, const char *name, const char *service, enum mdns_sd_proto proto, u16_t port, u32_t dns_ttl, service_get_txt_fn_t txt_fn, void *txt_data) +{ + int i; + int slot = -1; + struct mdns_service *srv; + struct mdns_host* mdns; + + LWIP_ASSERT("mdns_resp_add_service: netif != NULL", netif); + mdns = NETIF_TO_HOST(netif); + LWIP_ERROR("mdns_resp_add_service: Not an mdns netif", (mdns != NULL), return ERR_VAL); + + LWIP_ERROR("mdns_resp_add_service: Name too long", (strlen(name) <= MDNS_LABEL_MAXLEN), return ERR_VAL); + LWIP_ERROR("mdns_resp_add_service: Service too long", (strlen(service) <= MDNS_LABEL_MAXLEN), return ERR_VAL); + LWIP_ERROR("mdns_resp_add_service: Bad proto (need TCP or UDP)", (proto == DNSSD_PROTO_TCP || proto == DNSSD_PROTO_UDP), return ERR_VAL); + + for (i = 0; i < MDNS_MAX_SERVICES; i++) { + if (mdns->services[i] == NULL) { + slot = i; + break; + } + } + LWIP_ERROR("mdns_resp_add_service: Service list full (increase MDNS_MAX_SERVICES)", (slot >= 0), return ERR_MEM); + + srv = (struct mdns_service*)mem_malloc(sizeof(struct mdns_service)); + LWIP_ERROR("mdns_resp_add_service: Alloc failed", (srv != NULL), return ERR_MEM); + + memset(srv, 0, sizeof(struct mdns_service)); + + MEMCPY(&srv->name, name, LWIP_MIN(MDNS_LABEL_MAXLEN, strlen(name))); + MEMCPY(&srv->service, service, LWIP_MIN(MDNS_LABEL_MAXLEN, strlen(service))); + srv->txt_fn = txt_fn; + srv->txt_userdata = txt_data; + srv->proto = (u16_t)proto; + srv->port = port; + srv->dns_ttl = dns_ttl; + + mdns->services[slot] = srv; + + /* Announce on IPv6 and IPv4 */ +#if LWIP_IPV6 + mdns_announce(netif, IP6_ADDR_ANY); +#endif +#if LWIP_IPV4 + mdns_announce(netif, IP4_ADDR_ANY); +#endif + + return ERR_OK; +} + +/** + * @ingroup mdns + * Call this function from inside the service_get_txt_fn_t callback to add text data. + * Buffer for TXT data is 256 bytes, and each field is prefixed with a length byte. + * @param service The service provided to the get_txt callback + * @param txt String to add to the TXT field. + * @param txt_len Length of string + * @return ERR_OK if the string was added to the reply, an err_t otherwise + */ +err_t +mdns_resp_add_service_txtitem(struct mdns_service *service, const char *txt, u8_t txt_len) +{ + LWIP_ASSERT("mdns_resp_add_service_txtitem: service != NULL", service); + + /* Use a mdns_domain struct to store txt chunks since it is the same encoding */ + return mdns_domain_add_label(&service->txtdata, txt, txt_len); +} + +#endif /* LWIP_MDNS_RESPONDER */ |