feat: DNS resolver — enable lwIP DNS, kernel dns_resolve() wrapper with async callbac...

diff --git a/Makefile b/Makefile
index 686d3ce6dc99d989608ac26a4bde61c51a6c06d4..404e8630b1e9c2fb4530f4b2b48e67242924f40a 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ ifeq ($(ARCH),x86)
         $(LWIPDIR)/core/netif.c $(LWIPDIR)/core/pbuf.c $(LWIPDIR)/core/raw.c \
         $(LWIPDIR)/core/stats.c $(LWIPDIR)/core/sys.c $(LWIPDIR)/core/tcp.c \
         $(LWIPDIR)/core/tcp_in.c $(LWIPDIR)/core/tcp_out.c $(LWIPDIR)/core/timeouts.c \
-        $(LWIPDIR)/core/udp.c
+        $(LWIPDIR)/core/udp.c $(LWIPDIR)/core/dns.c
     LWIP_IPV4 := $(LWIPDIR)/core/ipv4/etharp.c $(LWIPDIR)/core/ipv4/icmp.c \
         $(LWIPDIR)/core/ipv4/ip4.c $(LWIPDIR)/core/ipv4/ip4_addr.c \
         $(LWIPDIR)/core/ipv4/ip4_frag.c

diff --git a/include/dns.h b/include/dns.h
new file mode 100644 (file)
index 0000000..d33fd92
--- /dev/null
+++ b/include/dns.h
@@ -0,0 +1,9 @@
+#ifndef DNS_H
+#define DNS_H
+
+#include <stdint.h>
+
+void dns_resolver_init(uint32_t server_ip);
+int  dns_resolve(const char* hostname, uint32_t* out_ip);
+
+#endif

diff --git a/src/net/dns.c b/src/net/dns.c
new file mode 100644 (file)
index 0000000..c24e8cd
--- /dev/null
+++ b/src/net/dns.c
@@ -0,0 +1,62 @@
+#include "dns.h"
+#include "uart_console.h"
+
+#include "lwip/dns.h"
+#include "lwip/ip_addr.h"
+
+void dns_resolver_init(uint32_t server_ip) {
+    dns_init();
+    ip_addr_t dns_server;
+    IP4_ADDR(&dns_server, (server_ip >> 24) & 0xFF,
+                          (server_ip >> 16) & 0xFF,
+                          (server_ip >> 8) & 0xFF,
+                          server_ip & 0xFF);
+    dns_setserver(0, &dns_server);
+    uart_print("[DNS] Resolver initialized\n");
+}
+
+static volatile int dns_done;
+static volatile uint32_t dns_result_ip;
+
+static void dns_found_cb(const char* name, const ip_addr_t* ipaddr, void* arg) {
+    (void)name;
+    (void)arg;
+    if (ipaddr) {
+        dns_result_ip = ip4_addr_get_u32(ip_2_ip4(ipaddr));
+    } else {
+        dns_result_ip = 0;
+    }
+    dns_done = 1;
+}
+
+int dns_resolve(const char* hostname, uint32_t* out_ip) {
+    if (!hostname || !out_ip) return -1;
+
+    ip_addr_t resolved;
+    dns_done = 0;
+    dns_result_ip = 0;
+
+    err_t err = dns_gethostbyname(hostname, &resolved, dns_found_cb, 0);
+    if (err == ERR_OK) {
+        /* Already cached */
+        *out_ip = ip4_addr_get_u32(ip_2_ip4(&resolved));
+        return 0;
+    }
+    if (err == ERR_INPROGRESS) {
+        /* Wait for callback — simple busy-wait with timeout */
+        extern uint32_t get_tick_count(void);
+        uint32_t deadline = get_tick_count() + 250; /* 5 second timeout at 50Hz */
+        while (!dns_done && get_tick_count() < deadline) {
+            /* Let lwIP process packets */
+            extern void schedule(void);
+            schedule();
+        }
+        if (dns_done && dns_result_ip != 0) {
+            *out_ip = dns_result_ip;
+            return 0;
+        }
+        return -2; /* timeout or NXDOMAIN */
+    }
+
+    return -1; /* error */
+}

diff --git a/src/net/lwip_port/lwipopts.h b/src/net/lwip_port/lwipopts.h
index 2146ebd7802cbc8f4307b08a461dec87ca67fb43..662be298a424ce098c8738d21c3d6334ae110dee 100644 (file)
--- a/src/net/lwip_port/lwipopts.h
+++ b/src/net/lwip_port/lwipopts.h
@@ -28,7 +28,8 @@
 #define LWIP_TCP                1
 #define LWIP_DHCP               0
 #define LWIP_AUTOIP             0
-#define LWIP_DNS                0
+#define LWIP_DNS                1
+#define LWIP_NO_CTYPE_H         1
 #define LWIP_IGMP               0
 
 /* ---- TCP tuning ---- */