Minor changes on DNS client.

src/api/api_msg.c

@@ -1029,13 +1029,13 @@ do_gethostbyname(void *arg)
   res = dns_gethostbyname(msg->name, msg->addr, do_dns_found, msg);
   if (res != DNS_QUERY_QUEUED) {
     /* If not queued, return to app thread directly */
-    if (res == DNS_QUERY_INVALID) {
-      /* some error occurred */
-      *msg->err = ERR_ARG;
-    } else if (res == DNS_COMPLETE) {
+    if (res == DNS_COMPLETE) {
       /* name was already in octet notation or cached */
       *msg->err = ERR_OK;
-    }
+    } else {
+      /* some error occurred */
+      *msg->err = ERR_ARG;
+    };
     /* on error or immediate success, wake up the application
      * task waiting in netconn_gethostbyname */
     sys_sem_signal(msg->sem);

src/api/sockets.c

@@ -1813,18 +1813,20 @@ lwip_fill_hostent(struct hostent *he, char *name, struct ip_addr **addr, char **
   he->h_addr_list = (char**)addr;
 }
 
-
 struct hostent*
-gethostbyname(const char *name)
+lwip_gethostbyname(const char *name)
 {
   err_t err;
   struct ip_addr addr;
 
+  /* query host IP address */
   err = netconn_gethostbyname(name, &addr);
   if (err != ERR_OK) {
+    LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
     return NULL;
   }
 
+  /* fill hostent */
   s_hostent_addr = addr;
   s_phostent_addr = &s_hostent_addr;
   s_hostent.h_name = (char*)name;
@@ -1833,6 +1835,29 @@ gethostbyname(const char *name)
   s_hostent.h_length = sizeof(struct ip_addr);
   s_hostent.h_addr_list = (char**)&s_phostent_addr;
 
+#if DNS_DEBUG
+  /* dump hostent */
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name           == %s\n",      s_hostent.h_name));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases        == 0x%08lX\n",(u32_t)(s_hostent.h_aliases)));
+  if (s_hostent.h_aliases != NULL) {
+    u8_t idx;
+    for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == 0x%08lX\n", idx, s_hostent.h_aliases[idx]));
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == %s\n",      idx, s_hostent.h_aliases[idx]));
+    }
+  }
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype       == %lu\n",    (u32_t)(s_hostent.h_addrtype)));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length         == %lu\n",    (u32_t)(s_hostent.h_length)));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list      == 0x%08lX\n", s_hostent.h_addr_list));
+  if (s_hostent.h_addr_list != NULL) {
+    u8_t idx;
+    for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]   == 0x%08lX\n", idx, s_hostent.h_addr_list[idx]));
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n",      idx, inet_ntoa(*((struct in_addr*)(s_hostent.h_addr_list[idx])))));
+    }
+  }
+#endif /* DNS_DEBUG */
+
   return &s_hostent;
 }
 #endif /* LWIP_DNS*/

src/core/dns.c

@@ -400,13 +400,13 @@ dns_send(const char* name, u8_t id)
 
     memcpy( query, dns_endquery, sizeof(dns_endquery));
 
-    // resize pbuf to the exact dns query
+    /* resize pbuf to the exact dns query */
     pbuf_realloc(p, (query+sizeof(dns_endquery))-((char*)(p->payload)));
 
-    // send dns packet
+    /* send dns packet */
     udp_send(dns_pcb, p);
 
-    // free pbuf
+    /* free pbuf */
     pbuf_free(p);
 
     return ERR_OK;
@@ -485,6 +485,8 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
   struct dns_hdr *hdr;
   struct dns_table_entry *pEntry;
   u8_t nquestions, nanswers;
+
+  LWIP_ASSERT("dns_recv: pbuf chain not yet supported", (p->next==NULL));
   
   hdr = (struct dns_hdr *)p->payload;
 
@@ -514,7 +516,7 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
     nquestions = htons(hdr->numquestions);
     nanswers   = htons(hdr->numanswers);
 
-    /* Skip the name in the question. XXX: This should really be checked
+    /* Skip the name in the "question" part. This should really be checked
        agains the name in the question, to be sure that they match. */
     pHostname = (char *) dns_parse_name((unsigned char *)p->payload + sizeof(struct dns_hdr)) + 4/*type(2)+class(2)*/;
 
@@ -524,7 +526,6 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
       if(*pHostname & 0xc0) {
         /* Compressed name. */
         pHostname +=2;
-        /* printf("Compressed anwser\n");*/
       } else {
         /* Not compressed name. */
         pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
@@ -532,9 +533,6 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
 
       /* TODO: isn't it any problem to access to dns_answer fields since pHostname's length can be unaligned? */
       ans = (struct dns_answer *)pHostname;
-      /* printf("Answer: type %x, class %x, ttl %x, length %x\n",
-         htons(ans->type), htons(ans->class), (htons(ans->ttl[0])
-           << 16) | htons(ans->ttl[1]), htons(ans->len));*/
 
       /* Check for IP address type and Internet class. Others are discarded. */
       if((ntohs(ans->type) == DNS_RRTYPE_A) && (ntohs(ans->class) == DNS_RRCLASS_IN) && (ntohs(ans->len) == 4/*IPv4 address*/) ) {
@@ -548,7 +546,7 @@ dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16
           (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
         return;
       } else {
-        pHostname = pHostname + 10 + htons(ans->len);
+        pHostname = pHostname + 10 /*type(2)+class(2)+ttl(4)+len(2)*/ + htons(ans->len);
       }
       --nanswers;
     }

src/core/init.c

@@ -194,6 +194,10 @@ lwip_sanity_check(void)
   if (TCP_WND < TCP_MSS)
     LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_WND is smaller than MSS\n"));
 #endif /* LWIP_TCP */
+#if LWIP_DNS
+  if (PBUF_POOL_BUFSIZE<(PBUF_LINK_HLEN+PBUF_IP_HLEN+PBUF_TRANSPORT_HLEN+DNS_MSG_SIZE))
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: UDP messages for DNS could need until 512 bytes\n"));
+#endif /* LWIP_DNS */
 }
 #else  /* LWIP_DEBUG */
 #define lwip_sanity_check()

src/include/lwip/dns.h

@@ -43,6 +43,9 @@
 #define DNS_TMR_INTERVAL 1000
 #endif
 
+/** DNS message max. size */
+#define DNS_MSG_SIZE     512
+
 /* enumerated list of possible result values returned by dns_gethostname() */
 typedef enum dns_result {
   DNS_QUERY_INVALID,

src/include/lwip/sockets.h

@@ -314,7 +314,7 @@ int lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptse
 int lwip_ioctl(int s, long cmd, void *argp);
 
 #if LWIP_DNS
-struct hostent *gethostbyname(const char *name);
+struct hostent *lwip_gethostbyname(const char *name);
 #endif /* LWIP_DNS */
 
 #if LWIP_COMPAT_SOCKETS
@@ -335,6 +335,7 @@ struct hostent *gethostbyname(const char *name);
 #define socket(a,b,c)         lwip_socket(a,b,c)
 #define select(a,b,c,d,e)     lwip_select(a,b,c,d,e)
 #define ioctlsocket(a,b,c)    lwip_ioctl(a,b,c)
+#define gethostbyname(a)      lwip_gethostbyname(a)
 
 #if LWIP_POSIX_SOCKETS_IO_NAMES
 #define read(a,b,c)           lwip_read(a,b,c)