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https://github.com/lwip-tcpip/lwip.git
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Changes on DNS client. Add multiples dns servers support.
This commit is contained in:
fbernon
parent
9dd4ad6c1f
commit
8ff1194b6a
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@ -522,6 +522,9 @@ static void dhcp_handle_ack(struct netif *netif)
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dns_setserver( n, (struct ip_addr *)(&(dhcp->offered_dns_addr[n].addr)));
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#endif /* LWIP_DNS */
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}
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#if LWIP_DNS
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dns_setserver( n, &ip_addr_any);
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#endif /* LWIP_DNS */
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}
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}
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174
src/core/dns.c
174
src/core/dns.c
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@ -65,7 +65,6 @@
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*----------------------------------------------------------------------------*/
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/** @todo: define good default values (rfc compliance) */
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/** @todo: secondary server support */
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/** @todo: pbuf chain not yet supported */
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/** @todo: improve answer parsing, more checkings... */
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@ -104,7 +103,7 @@
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/* The maximum number of retries when asking for a name, before "timeout". */
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#ifndef DNS_MAX_RETRIES
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#define DNS_MAX_RETRIES 8
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#define DNS_MAX_RETRIES 4
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#endif
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/* DNS entry time to live (in DNS_TMR_INTERVAL ticks) */
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@ -191,6 +190,7 @@ PACK_STRUCT_BEGIN
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/** DNS table entry */
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struct dns_table_entry {
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u8_t state;
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u8_t numdns;
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u8_t tmr;
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u8_t retries;
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u8_t ttl;
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@ -218,6 +218,7 @@ static void dns_check_entries(void);
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static struct udp_pcb *dns_pcb;
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static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
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static u8_t dns_seqno;
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static struct ip_addr dns_servers[DNS_MAX_SERVERS];
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/**
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* Initialize the resolver and configure which DNS server to use for queries.
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@ -249,7 +250,7 @@ dns_init()
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udp_recv(dns_pcb, dns_recv, NULL);
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/* initialize default DNS primary server */
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dns_setserver(0, &dnsserver);
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dns_setserver(0, &dnsserver);
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}
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}
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return ERR_OK;
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@ -264,9 +265,8 @@ dns_init()
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void
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dns_setserver(u8_t numdns, struct ip_addr *dnsserver)
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{
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LWIP_UNUSED_ARG(numdns);
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if ((dns_pcb != NULL) && (dnsserver != NULL) && (dnsserver->addr !=0 )) {
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udp_connect( dns_pcb, dnsserver, DNS_SERVER_PORT);
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if ((numdns<DNS_MAX_SERVERS) && (dns_pcb != NULL) && (dnsserver != NULL) && (dnsserver->addr !=0 )) {
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dns_servers[numdns] = (*dnsserver);
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}
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}
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@ -276,11 +276,10 @@ dns_setserver(u8_t numdns, struct ip_addr *dnsserver)
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* the currently configured DNS server or NULL if no DNS server has
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* been configured.
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*/
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u32_t
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struct ip_addr
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dns_getserver(u8_t numdns)
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{
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LWIP_UNUSED_ARG(numdns);
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return ((dns_pcb != NULL)?dns_pcb->remote_ip.addr:0);
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return (((numdns<DNS_MAX_SERVERS) && (dns_pcb != NULL))?dns_servers[numdns]:(*IP_ADDR_ANY));
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}
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/**
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@ -356,7 +355,7 @@ dns_parse_name(unsigned char *query)
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* dns_send
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*/
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static err_t
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dns_send(const char* name, u8_t id)
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dns_send(u8_t numdns, const char* name, u8_t id)
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{
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struct dns_hdr *hdr;
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struct dns_query *qry;
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@ -365,7 +364,7 @@ dns_send(const char* name, u8_t id)
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const char *pHostname;
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u8_t n;
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LWIP_DEBUGF(DNS_DEBUG, ("dns_send: \"%s\": request\n", name));
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LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n", (u16_t)(numdns), name));
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/* if here, we have either a new query or a retry on a previous query to process */
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p = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dns_hdr)+DNS_MAX_NAME_LENGTH+sizeof(struct dns_query), PBUF_RAM);
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@ -403,7 +402,7 @@ dns_send(const char* name, u8_t id)
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pbuf_realloc(p, (query+sizeof(struct dns_query))-((char*)(p->payload)));
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/* send dns packet */
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udp_send(dns_pcb, p);
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udp_sendto(dns_pcb, p, dns_servers+numdns, DNS_SERVER_PORT);
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/* free pbuf */
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pbuf_free(p);
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@ -433,14 +432,22 @@ dns_check_entries(void)
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if (pEntry->state == DNS_STATE_ASKING) {
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if (--pEntry->tmr == 0) {
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if (++pEntry->retries == DNS_MAX_RETRIES) {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entries: \"%s\": timeout\n", pEntry->name));
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/* call specified callback function if provided */
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if (pEntry->found)
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(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
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/* flush this entry */
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pEntry->state = DNS_STATE_UNUSED;
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pEntry->found = NULL;
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continue;
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if ((pEntry->numdns+1<DNS_MAX_SERVERS) && (dns_servers[pEntry->numdns+1].addr!=0)) {
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/* change of server */
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pEntry->numdns++;
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pEntry->tmr = 1;
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pEntry->retries = 0;
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continue;
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} else {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entries: \"%s\": timeout\n", pEntry->name));
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/* call specified callback function if provided */
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if (pEntry->found)
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(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
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/* flush this entry */
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pEntry->state = DNS_STATE_UNUSED;
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pEntry->found = NULL;
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continue;
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}
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}
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/* wait longer for the next retry */
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pEntry->tmr = pEntry->retries;
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@ -450,11 +457,12 @@ dns_check_entries(void)
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}
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} else {
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pEntry->state = DNS_STATE_ASKING;
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pEntry->numdns = 0;
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pEntry->tmr = 1;
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pEntry->retries = 0;
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}
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/* send DNS packet for this entry */
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dns_send(pEntry->name, i);
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dns_send(pEntry->numdns, pEntry->name, i);
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break;
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}
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@ -485,65 +493,85 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
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struct dns_table_entry *pEntry;
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u8_t nquestions, nanswers;
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LWIP_ASSERT("dns_recv: pbuf chain not yet supported", (p->next==NULL));
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hdr = (struct dns_hdr *)p->payload;
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/* is the dns message in a pbuf chain ? */
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if (p->next != NULL) {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf chain not yet supported\n"));
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pbuf_free(p);
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return;
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}
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/* is the dns message big enought ? */
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if (p->tot_len < (sizeof(struct dns_hdr)+sizeof(struct dns_query)+sizeof(struct dns_answer))) {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
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pbuf_free(p);
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return;
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}
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/** @todo: check RFC1035 - 7.3. Processing responses */
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/* The ID in the DNS header should be our entry into the name table. */
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hdr = (struct dns_hdr *)p->payload;
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i = htons(hdr->id);
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pEntry = &dns_table[i];
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if( (i < DNS_TABLE_SIZE) && (pEntry->state == DNS_STATE_ASKING) ) {
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/* This entry is now completed. */
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pEntry->state = DNS_STATE_DONE;
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pEntry->ttl = DNS_TTL_ENTRY;
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pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
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if(i < DNS_TABLE_SIZE) {
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pEntry = &dns_table[i];
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if(pEntry->state == DNS_STATE_ASKING) {
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/* This entry is now completed. */
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pEntry->state = DNS_STATE_DONE;
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pEntry->ttl = DNS_TTL_ENTRY;
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pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
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/* We only care about the question(s) and the answers. The authrr
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and the extrarr are simply discarded. */
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nquestions = htons(hdr->numquestions);
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nanswers = htons(hdr->numanswers);
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/* We only care about the question(s) and the answers. The authrr
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and the extrarr are simply discarded. */
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nquestions = htons(hdr->numquestions);
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nanswers = htons(hdr->numanswers);
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/* Check for error. If so, call callback to inform. */
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if (((hdr->flags1 & DNS_FLAG1_RESPONSE)==0) ||(pEntry->err != 0) || (nquestions != 1)) {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
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/* call specified callback function if provided */
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if (pEntry->found)
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(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
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/* flush this entry */
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pEntry->state = DNS_STATE_UNUSED;
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pEntry->found = NULL;
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return;
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}
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/* Skip the name in the "question" part. This should really be checked
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agains the name in the question, to be sure that they match. */
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pHostname = (char *) dns_parse_name((unsigned char *)p->payload + sizeof(struct dns_hdr)) + sizeof(struct dns_query);
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while(nanswers > 0) {
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/* skip answer resource record's host name */
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pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
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/* Check for IP address type and Internet class. Others are discarded. */
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ans = (struct dns_answer *)pHostname;
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if((ntohs(ans->type) == DNS_RRTYPE_A) && (ntohs(ans->class) == DNS_RRCLASS_IN) && (ntohs(ans->len) == sizeof(struct ip_addr)) ) {
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/* read the IP address after answer resource record's header */
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pEntry->ipaddr = (*((struct ip_addr*)(ans+1)));
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
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ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
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LWIP_DEBUGF(DNS_DEBUG, ("\n"));
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/* Check for error. If so, call callback to inform. */
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if (((hdr->flags1 & DNS_FLAG1_RESPONSE)==0) ||(pEntry->err != 0) || (nquestions != 1)) {
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
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/* call specified callback function if provided */
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if (pEntry->found)
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(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
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(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
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/* flush this entry */
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pEntry->state = DNS_STATE_UNUSED;
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pEntry->found = NULL;
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/* free pbuf */
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pbuf_free(p);
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return;
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} else {
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pHostname = pHostname + sizeof(struct dns_answer) + htons(ans->len);
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}
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--nanswers;
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/* Skip the name in the "question" part. This should really be checked
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agains the name in the question, to be sure that they match. */
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pHostname = (char *) dns_parse_name((unsigned char *)p->payload + sizeof(struct dns_hdr)) + sizeof(struct dns_query);
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while(nanswers > 0) {
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/* skip answer resource record's host name */
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pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
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/* Check for IP address type and Internet class. Others are discarded. */
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ans = (struct dns_answer *)pHostname;
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if((ntohs(ans->type) == DNS_RRTYPE_A) && (ntohs(ans->class) == DNS_RRCLASS_IN) && (ntohs(ans->len) == sizeof(struct ip_addr)) ) {
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/* read the IP address after answer resource record's header */
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pEntry->ipaddr = (*((struct ip_addr*)(ans+1)));
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
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ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
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LWIP_DEBUGF(DNS_DEBUG, ("\n"));
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/* call specified callback function if provided */
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if (pEntry->found)
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(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
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/* free pbuf */
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pbuf_free(p);
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return;
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} else {
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pHostname = pHostname + sizeof(struct dns_answer) + htons(ans->len);
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}
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--nanswers;
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}
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
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}
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LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
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}
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/* free pbuf */
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pbuf_free(p);
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}
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/**
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@ -584,11 +612,11 @@ dns_query(const char *name, void (*found)(const char *name, struct ip_addr *addr
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}
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/* fill the entry */
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strcpy(pEntry->name, name);
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pEntry->found = found;
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pEntry->arg = arg;
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pEntry->state = DNS_STATE_NEW;
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pEntry->seqno = dns_seqno++;
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pEntry->state = DNS_STATE_NEW;
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pEntry->seqno = dns_seqno++;
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pEntry->found = found;
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pEntry->arg = arg;
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strcpy( pEntry->name, name);
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}
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/**
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@ -40,7 +40,12 @@
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/** DNS timer period */
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#ifndef DNS_TMR_INTERVAL
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#define DNS_TMR_INTERVAL 1000
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#define DNS_TMR_INTERVAL 1000
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#endif
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/** The maximum of DNS servers */
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#ifndef DNS_MAX_SERVERS
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#define DNS_MAX_SERVERS 2
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#endif
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/** DNS message max. size */
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@ -89,10 +94,7 @@ void dns_tmr(void);
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void dns_setserver(u8_t numdns, struct ip_addr *dnsserver);
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/* returns configured DNS server IP address */
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u32_t dns_getserver(u8_t numdns);
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/* returns IP for host 'name' only if already in table */
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u32_t dns_lookup(const char *name);
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struct ip_addr dns_getserver(u8_t numdns);
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/* resolves a host 'name' in ip address */
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DNS_RESULT dns_gethostbyname(const char *hostName, struct ip_addr *addr,
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