Merge branch 'lukeshu/cover'

7 files changed, 266 insertions, 102 deletions

diff --git a/libdhcp/CMakeLists.txt b/libdhcp/CMakeLists.txt
index dee7cb6..f14e46d 100644
--- a/libdhcp/CMakeLists.txt
+++ b/libdhcp/CMakeLists.txt
@@ -7,7 +7,14 @@ add_library(libdhcp INTERFACE)
 target_include_directories(libdhcp PUBLIC INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/include)
 target_sources(libdhcp INTERFACE
 	dhcp_client.c
+	dhcp_common.c
 )
 target_link_libraries(libdhcp INTERFACE
 	libmisc
+	libhw_generic
 )
+
+if (ENABLE_TESTS)
+	add_lib_test(libdhcp test_client)
+	target_link_libraries(test_client libcr libhw_cr)
+endif()
diff --git a/libdhcp/dhcp_client.c b/libdhcp/dhcp_client.c
index bf88961..57a2f60 100644
--- a/libdhcp/dhcp_client.c
+++ b/libdhcp/dhcp_client.c
@@ -179,9 +179,10 @@ static const char *state_strs[] = {
 };
 
 /**
- * For convenience in switch blocks, a list of the states that, when
- * msgtyp==DHCP_MSGTYP_REQUEST, dhcp_client_send() has assert()ed the state is
- * not.
+ * IMPOSSIBLE_REQUEST_STATES is a convenience macro for use in switch
+ * blocks; it is a list of the states that (when
+ * msgtyp==DHCP_MSGTYP_REQUEST) dhcp_client_send() has assert()ed the
+ * state is not.
  */
 #define IMPOSSIBLE_REQUEST_STATES \
 		     STATE_INIT: \
@@ -700,14 +701,6 @@ static ssize_t dhcp_client_recv(struct dhcp_client *client, struct dhcp_recv_msg
 	return 0;
 }
 
-/** @return true if there's a conflict, false if the addr appears to be unused */
-static bool dhcp_check_conflict(lo_interface net_packet_conn sock, struct net_ip4_addr addr) {
-	assert(!LO_IS_NULL(sock));
-	ssize_t v = LO_CALL(sock, sendto, "CHECK_IP_CONFLICT", 17, addr, 5000);
-	log_debugln("check_ip_conflict => ", v);
-	return v != -NET_EARP_TIMEOUT;
-}
-
 static void dhcp_client_take_lease(struct dhcp_client *client, struct dhcp_recv_msg *msg, bool ifup) {
 	assert(client);
 	assert(msg);
@@ -805,7 +798,7 @@ static void dhcp_client_setstate(struct dhcp_client *client,
 					dhcp_client_setstate(client, STATE_INIT, 0, NULL, scratch_msg);
 					break;
 				case DHCP_MSGTYP_ACK:
-					if (dhcp_check_conflict(client->sock, client->lease_client_addr)) {
+					if (LO_CALL(client->iface, arp_ping, client->lease_client_addr)) {
 						log_debugln("IP ", (net_ip4_addr, client->lease_client_addr), " is already in use");
 						dhcp_client_setstate(client, STATE_INIT, DHCP_MSGTYP_DECLINE, "IP is already in use", scratch_msg);
 					} else {
diff --git a/libdhcp/dhcp_common.c b/libdhcp/dhcp_common.c
new file mode 100644
index 0000000..d691836
--- /dev/null
+++ b/libdhcp/dhcp_common.c
@@ -0,0 +1,104 @@
+/* libdhcp/dhcp_common.c - Base definitions for the DHCP protocol
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include "dhcp_common.h"
+
+/**
+ * DHCP Options
+ * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml#options
+ */
+bool dhcp_opt_length_is_valid(uint8_t opt, uint16_t len) {
+	switch (opt) {
+	/* RFC 2132 */
+	case DHCP_OPT_PAD:               return len == 0;
+	case DHCP_OPT_SUBNET_MASK:       return len == 4;
+	case DHCP_OPT_TIME_OFFSET:       return len == 4;
+	case DHCP_OPT_ROUTER:            return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_TIME_SERVER:       return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_NAME_SERVER:       return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_DOMAIN_SERVER:     return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_LOG_SERVER:        return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_QUOTES_SERVER:     return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_LPR_SERVER:        return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_IMPRESS_SERVER:    return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_RLP_SERVER:        return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_HOSTNAME:          return len >= 1;
+	case DHCP_OPT_BOOT_FILE_SIZE:    return len == 2;
+	case DHCP_OPT_MERIT_DUMP_FILE:   return len >= 1;
+	case DHCP_OPT_DOMAIN_NAME:       return len >= 1;
+	case DHCP_OPT_SWAP_SERVER:       return len == 4; /* IANA says length is "N", but RFC 2132 says "length is 4"; likely releated to errata ID 487 */
+	case DHCP_OPT_ROOT_PATH:         return len >= 1;
+	case DHCP_OPT_EXTENSION_FILE:    return len >= 1;
+	case DHCP_OPT_FORWARD_ONOFF:     return len == 1;
+	case DHCP_OPT_SRCRTE_ONOFF:      return len == 1;
+	case DHCP_OPT_POLICY_FILTER:     return len >= 8 && len % 8 == 0;
+	case DHCP_OPT_MAX_DG_ASSEMBLY:   return len == 2;
+	case DHCP_OPT_DEFAULT_IP_TTL:    return len == 1;
+	case DHCP_OPT_MTU_TIMEOUT:       return len == 4;
+	case DHCP_OPT_MTU_PLATEAU:       return len >= 2 && len % 2 == 0;
+	case DHCP_OPT_MTU_INTERFACE:     return len == 2;
+	case DHCP_OPT_MTU_SUBNET:        return len == 1;
+	case DHCP_OPT_BROADCAST_ADDRESS: return len == 4;
+	case DHCP_OPT_MASK_DISCOVERY:    return len == 1;
+	case DHCP_OPT_MASK_SUPPLIER:     return len == 1;
+	case DHCP_OPT_ROUTER_DISCOVERY:  return len == 1;
+	case DHCP_OPT_ROUTER_REQUEST:    return len == 4;
+	case DHCP_OPT_STATIC_ROUTE:      return len >= 8 && len % 8 == 0;
+	case DHCP_OPT_TRAILERS:          return len == 1;
+	case DHCP_OPT_ARP_TIMEOUT:       return len == 4;
+	case DHCP_OPT_ETHERNET:          return len == 1;
+	case DHCP_OPT_DEFAULT_TCP_TTL:   return len == 1;
+	case DHCP_OPT_KEEPALIVE_TIME:    return len == 4;
+	case DHCP_OPT_KEEPALIVE_DATA:    return len == 1;
+	case DHCP_OPT_NIS_DOMAIN:        return len >= 1;
+	case DHCP_OPT_NIS_SERVERS:       return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_NTP_SERVERS:       return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_VENDOR_SPECIFIC:   return len >= 1;
+	case DHCP_OPT_NETBIOS_NAME_SRV:  return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_NETBIOS_DIST_SRV:  return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_NETBIOS_NODE_TYPE: return len == 1;
+	case DHCP_OPT_NETBIOS_SCOPE:     return len >= 1;
+	case DHCP_OPT_X_WINDOW_FONT:     return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_X_WINDOW_MANAGER:  return len >= 4 && len % 4 == 0;
+	case DHCP_OPT_ADDRESS_REQUEST:   return len == 4;
+	case DHCP_OPT_ADDRESS_TIME:      return len == 4;
+	case DHCP_OPT_OVERLOAD:          return len == 1;
+	case DHCP_OPT_DHCP_MSG_TYPE:     return len == 1;
+	case DHCP_OPT_DHCP_SERVER_ID:    return len == 4;
+	case DHCP_OPT_PARAMETER_LIST:    return len >= 1;
+	case DHCP_OPT_DHCP_MESSAGE:      return len >= 1;
+	case DHCP_OPT_DHCP_MAX_MSG_SIZE: return len == 2;
+	case DHCP_OPT_RENEWAL_TIME:      return len == 4;
+	case DHCP_OPT_REBINDING_TIME:    return len == 4;
+	case DHCP_OPT_CLASS_ID:          return len >= 1;
+	case DHCP_OPT_CLIENT_ID:         return len >= 2;
+
+	/* RFC 2132 */
+	case DHCP_OPT_END:               return len == 0;
+
+	/* Unrecognized */
+	default:
+		return true;
+	}
+}
+
+/**
+ * DHCP Message Type 53 Values
+ * https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml#message-type-53
+ */
+const char *dhcp_msgtyp_str(uint8_t typ) {
+	switch (typ) {
+	case DHCP_MSGTYP_DISCOVER: return "DHCP_MSGTYP_DISCOVER";
+	case DHCP_MSGTYP_OFFER:    return "DHCP_MSGTYP_OFFER";
+	case DHCP_MSGTYP_REQUEST:  return "DHCP_MSGTYP_REQUEST";
+	case DHCP_MSGTYP_DECLINE:  return "DHCP_MSGTYP_DECLINE";
+	case DHCP_MSGTYP_ACK:      return "DHCP_MSGTYP_ACK";
+	case DHCP_MSGTYP_NAK:      return "DHCP_MSGTYP_NAK";
+	case DHCP_MSGTYP_RELEASE:  return "DHCP_MSGTYP_RELEASE";
+	case DHCP_MSGTYP_INFORM:   return "DHCP_MSGTYP_INFORM";
+	default:                   return const_byte_str(typ);
+	}
+}
diff --git a/libdhcp/dhcp_common.h b/libdhcp/dhcp_common.h
index 5b51ce2..a0cdd3c 100644
--- a/libdhcp/dhcp_common.h
+++ b/libdhcp/dhcp_common.h
@@ -1,6 +1,6 @@
 /* libdhcp/dhcp_common.h - Base definitions for the DHCP protocol
  *
- * Copyright (C) 2024  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * -----------------------------------------------------------------------------
@@ -67,8 +67,9 @@
 #ifndef _LIBDHCP_DHCP_COMMON_H_
 #define _LIBDHCP_DHCP_COMMON_H_
 
-#include <libmisc/endian.h>
-#include <libmisc/log.h> /* for const_byte_str() */
+#include <libhw/generic/net.h> /* for struct net_ip4_addr */
+#include <libmisc/endian.h>    /* for uint{n}be_t */
+#include <libmisc/log.h>       /* for const_byte_str() */
 
 /* Config *********************************************************************/
 
@@ -215,80 +216,7 @@ static const uint8_t dhcp_magic_cookie[] = {99, 130, 83, 99};
                                                        /* ... */
 #define DHCP_OPT_END                    ((uint8_t)255) /* RFC2132: length: 0; meaning: None */
 
-static inline bool dhcp_opt_length_is_valid(uint8_t opt, uint16_t len) {
-	switch (opt) {
-	/* RFC 2132 */
-	case DHCP_OPT_PAD:               return len == 0;
-	case DHCP_OPT_SUBNET_MASK:       return len == 4;
-	case DHCP_OPT_TIME_OFFSET:       return len == 4;
-	case DHCP_OPT_ROUTER:            return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_TIME_SERVER:       return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_NAME_SERVER:       return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_DOMAIN_SERVER:     return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_LOG_SERVER:        return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_QUOTES_SERVER:     return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_LPR_SERVER:        return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_IMPRESS_SERVER:    return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_RLP_SERVER:        return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_HOSTNAME:          return len >= 1;
-	case DHCP_OPT_BOOT_FILE_SIZE:    return len == 2;
-	case DHCP_OPT_MERIT_DUMP_FILE:   return len >= 1;
-	case DHCP_OPT_DOMAIN_NAME:       return len >= 1;
-	case DHCP_OPT_SWAP_SERVER:       return len == 4; /* IANA says length is "N", but RFC 2132 says "length is 4"; likely releated to errata ID 487 */
-	case DHCP_OPT_ROOT_PATH:         return len >= 1;
-	case DHCP_OPT_EXTENSION_FILE:    return len >= 1;
-	case DHCP_OPT_FORWARD_ONOFF:     return len == 1;
-	case DHCP_OPT_SRCRTE_ONOFF:      return len == 1;
-	case DHCP_OPT_POLICY_FILTER:     return len >= 8 && len % 8 == 0;
-	case DHCP_OPT_MAX_DG_ASSEMBLY:   return len == 2;
-	case DHCP_OPT_DEFAULT_IP_TTL:    return len == 1;
-	case DHCP_OPT_MTU_TIMEOUT:       return len == 4;
-	case DHCP_OPT_MTU_PLATEAU:       return len >= 2 && len % 2 == 0;
-	case DHCP_OPT_MTU_INTERFACE:     return len == 2;
-	case DHCP_OPT_MTU_SUBNET:        return len == 1;
-	case DHCP_OPT_BROADCAST_ADDRESS: return len == 4;
-	case DHCP_OPT_MASK_DISCOVERY:    return len == 1;
-	case DHCP_OPT_MASK_SUPPLIER:     return len == 1;
-	case DHCP_OPT_ROUTER_DISCOVERY:  return len == 1;
-	case DHCP_OPT_ROUTER_REQUEST:    return len == 4;
-	case DHCP_OPT_STATIC_ROUTE:      return len >= 8 && len % 8 == 0;
-	case DHCP_OPT_TRAILERS:          return len == 1;
-	case DHCP_OPT_ARP_TIMEOUT:       return len == 4;
-	case DHCP_OPT_ETHERNET:          return len == 1;
-	case DHCP_OPT_DEFAULT_TCP_TTL:   return len == 1;
-	case DHCP_OPT_KEEPALIVE_TIME:    return len == 4;
-	case DHCP_OPT_KEEPALIVE_DATA:    return len == 1;
-	case DHCP_OPT_NIS_DOMAIN:        return len >= 1;
-	case DHCP_OPT_NIS_SERVERS:       return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_NTP_SERVERS:       return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_VENDOR_SPECIFIC:   return len >= 1;
-	case DHCP_OPT_NETBIOS_NAME_SRV:  return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_NETBIOS_DIST_SRV:  return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_NETBIOS_NODE_TYPE: return len == 1;
-	case DHCP_OPT_NETBIOS_SCOPE:     return len >= 1;
-	case DHCP_OPT_X_WINDOW_FONT:     return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_X_WINDOW_MANAGER:  return len >= 4 && len % 4 == 0;
-	case DHCP_OPT_ADDRESS_REQUEST:   return len == 4;
-	case DHCP_OPT_ADDRESS_TIME:      return len == 4;
-	case DHCP_OPT_OVERLOAD:          return len == 1;
-	case DHCP_OPT_DHCP_MSG_TYPE:     return len == 1;
-	case DHCP_OPT_DHCP_SERVER_ID:    return len == 4;
-	case DHCP_OPT_PARAMETER_LIST:    return len >= 1;
-	case DHCP_OPT_DHCP_MESSAGE:      return len >= 1;
-	case DHCP_OPT_DHCP_MAX_MSG_SIZE: return len == 2;
-	case DHCP_OPT_RENEWAL_TIME:      return len == 4;
-	case DHCP_OPT_REBINDING_TIME:    return len == 4;
-	case DHCP_OPT_CLASS_ID:          return len >= 1;
-	case DHCP_OPT_CLIENT_ID:         return len >= 2;
-
-	/* RFC 2132 */
-	case DHCP_OPT_END:               return len == 0;
-
-	/* Unrecognized */
-	default:
-		return true;
-	}
-};
+bool dhcp_opt_length_is_valid(uint8_t opt, uint16_t len);
 
 /**
  * DHCP Message Type 53 Values
@@ -303,18 +231,6 @@ static inline bool dhcp_opt_length_is_valid(uint8_t opt, uint16_t len) {
 #define DHCP_MSGTYP_RELEASE             ((uint8_t)  7) /* RFC2132, client->server */
 #define DHCP_MSGTYP_INFORM              ((uint8_t)  8) /* RFC2132, client->server */
 
-static const char *dhcp_msgtyp_str(uint8_t typ) {
-	switch (typ) {
-	case DHCP_MSGTYP_DISCOVER: return "DHCP_MSGTYP_DISCOVER";
-	case DHCP_MSGTYP_OFFER:    return "DHCP_MSGTYP_OFFER";
-	case DHCP_MSGTYP_REQUEST:  return "DHCP_MSGTYP_REQUEST";
-	case DHCP_MSGTYP_DECLINE:  return "DHCP_MSGTYP_DECLINE";
-	case DHCP_MSGTYP_ACK:      return "DHCP_MSGTYP_ACK";
-	case DHCP_MSGTYP_NAK:      return "DHCP_MSGTYP_NAK";
-	case DHCP_MSGTYP_RELEASE:  return "DHCP_MSGTYP_RELEASE";
-	case DHCP_MSGTYP_INFORM:   return "DHCP_MSGTYP_INFORM";
-	default:                   return const_byte_str(typ);
-	}
-}
+const char *dhcp_msgtyp_str(uint8_t typ);
 
 #endif /* _LIBDHCP_DHCP_COMMON_H_ */
diff --git a/libdhcp/tests/config.h b/libdhcp/tests/config.h
new file mode 100644
index 0000000..53079fe
--- /dev/null
+++ b/libdhcp/tests/config.h
@@ -0,0 +1,25 @@
+/* config.h - Compile-time configuration for the libdhcp tests
+ *
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _CONFIG_H_
+#define _CONFIG_H_
+
+#define CONFIG_COROUTINE_STACK_SIZE_DEFAULT    (16*1024)
+#define CONFIG_COROUTINE_NAME_LEN              16
+#define CONFIG_COROUTINE_NUM                   16
+
+#define CONFIG_COROUTINE_MEASURE_STACK         1
+#define CONFIG_COROUTINE_PROTECT_STACK         1
+#define CONFIG_COROUTINE_DEBUG                 1
+#define CONFIG_COROUTINE_VALGRIND              1
+#define CONFIG_COROUTINE_GDB                   1
+
+#define CONFIG_DHCP_CAN_RECV_UNICAST_IP_WITHOUT_IP      0 /* bool */
+#define CONFIG_DHCP_DEBUG                               1 /* bool */
+#define CONFIG_DHCP_OPT_SIZE                            312 /* minimum of 312 */
+#define CONFIG_DHCP_SELECTING_NS                        (5*NS_PER_S)
+
+#endif /* _CONFIG_H_ */
diff --git a/libdhcp/tests/test.h b/libdhcp/tests/test.h
new file mode 120000
index 0000000..2fb1bd5
--- /dev/null
+++ b/libdhcp/tests/test.h
@@ -0,0 +1 @@
+../../libmisc/tests/test.h
\ No newline at end of file
diff --git a/libdhcp/tests/test_client.c b/libdhcp/tests/test_client.c
new file mode 100644
index 0000000..90efd01
--- /dev/null
+++ b/libdhcp/tests/test_client.c
@@ -0,0 +1,118 @@
+/* libdhcp/tests/test_client.c - Tests for libdhcp client
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <string.h> /* for memcpy() */
+
+#include <libcr/coroutine.h>
+#include <libhw/generic/net.h>
+#include <libhw/host_alarmclock.h>
+
+#include <libdhcp/client.h>
+
+#include "test.h"
+
+/******************************************************************************/
+
+struct test_udp {
+};
+LO_IMPLEMENTATION_H(io_closer, struct test_udp, test_udp);
+LO_IMPLEMENTATION_C(io_closer, struct test_udp, test_udp, static);
+LO_IMPLEMENTATION_H(net_packet_conn, struct test_udp, test_udp);
+LO_IMPLEMENTATION_C(net_packet_conn, struct test_udp, test_udp, static);
+
+static ssize_t test_udp_sendto(struct test_udp *LM_UNUSED(self), void *LM_UNUSED(buf), size_t len, struct net_ip4_addr LM_UNUSED(node), uint16_t LM_UNUSED(port)) {
+	return len;
+}
+
+static ssize_t test_udp_recvfrom(struct test_udp *LM_UNUSED(self), void *buf, size_t len, struct net_ip4_addr *ret_node, uint16_t *ret_port) {
+	static const uint8_t resp_offer[] = {0x02,0x01,0x06,0x00,0xE8,0x40,0xC6,0x79,0x00,0x01,0x80,0x00,0x00,0x00,0x00,0x00,0xC0,0xA8,0x0A,0x78,0xC0,0xA8,0x0A,0x01,0x00,0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x63,0x82,0x53,0x63,0x35,0x01,0x02,0x36,0x04,0xC0,0xA8,0x0A,0x01,0x33,0x04,0x00,0x00,0xA8,0xC0,0x3A,0x04,0x00,0x00,0x54,0x60,0x3B,0x04,0x00,0x00,0x93,0xA8,0x01,0x04,0xFF,0xFF,0xFF,0x00,0x1C,0x04,0xC0,0xA8,0x0A,0xFF,0x03,0x04,0xC0,0xA8,0x0A,0x01,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
+	static const uint8_t resp_ack[]   = {0x02,0x01,0x06,0x00,0xE8,0x40,0xC6,0x79,0x00,0x01,0x80,0x00,0x00,0x00,0x00,0x00,0xC0,0xA8,0x0A,0x78,0xC0,0xA8,0x0A,0x01,0x00,0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x63,0x82,0x53,0x63,0x35,0x01,0x05,0x36,0x04,0xC0,0xA8,0x0A,0x01,0x33,0x04,0x00,0x00,0xA8,0xC0,0x3A,0x04,0x00,0x00,0x54,0x60,0x3B,0x04,0x00,0x00,0x93,0xA8,0x01,0x04,0xFF,0xFF,0xFF,0x00,0x1C,0x04,0xC0,0xA8,0x0A,0xFF,0x03,0x04,0xC0,0xA8,0x0A,0x01,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
+
+	static unsigned cnt = 0;
+	const void *resp;
+	size_t resp_len;
+	switch (cnt++) {
+	case 0: resp = resp_offer; resp_len = sizeof(resp_offer); break;
+	case 1: resp = resp_ack; resp_len = sizeof(resp_ack); break;
+	default: return -NET_ERECV_TIMEOUT;
+	}
+	test_assert(len >= resp_len);
+	memcpy(buf, resp, resp_len);
+	*ret_node = ((struct net_ip4_addr){{192,168,10,1}});
+	*ret_port = 67;
+	return resp_len;
+}
+
+static void test_udp_set_recv_deadline(struct test_udp *LM_UNUSED(self), uint64_t LM_UNUSED(ns_since_boot)) {
+	/* Do nothing?  */
+}
+
+static int test_udp_close(struct test_udp *LM_UNUSED(self)) {
+	assert_notreached("not implemented");
+}
+
+/******************************************************************************/
+
+struct test_iface {
+	struct net_iface_config cfg;
+
+	struct test_udp         conn;
+};
+LO_IMPLEMENTATION_H(net_iface, struct test_iface, test);
+LO_IMPLEMENTATION_C(net_iface, struct test_iface, test, static);
+
+static struct net_eth_addr test_hwaddr(struct test_iface *LM_UNUSED(self)) {
+	struct net_eth_addr ret = {{1, 2, 3, 4, 5, 6}};
+	return ret;
+}
+
+static void test_ifup(struct test_iface *LM_UNUSED(self), struct net_iface_config LM_UNUSED(cfg)) {
+	cr_exit();
+}
+
+static void test_ifdown(struct test_iface *LM_UNUSED(self)) {
+	assert_notreached("not implemented");
+}
+
+static bool test_arp_ping(struct test_iface *LM_UNUSED(self), struct net_ip4_addr LM_UNUSED(addr)) {
+	return false;
+}
+
+static lo_interface net_stream_listener test_tcp_listen(struct test_iface *LM_UNUSED(self), uint16_t LM_UNUSED(local_port)) {
+	assert_notreached("not implemented");
+}
+
+static lo_interface net_stream_conn test_tcp_dial(struct test_iface *LM_UNUSED(self), struct net_ip4_addr LM_UNUSED(remote_node), uint16_t LM_UNUSED(remote_port)) {
+	assert_notreached("not implemented");
+}
+
+static lo_interface net_packet_conn test_udp_conn(struct test_iface *self, uint16_t local_port) {
+	bool once = false;
+	test_assert(local_port == 68);
+	test_assert(!once);
+	once = true;
+	return lo_box_test_udp_as_net_packet_conn(&self->conn);
+}
+
+/******************************************************************************/
+
+COROUTINE dhcp_cr(void *) {
+	cr_begin();
+	struct test_iface iface = {};
+	dhcp_client_main(lo_box_test_as_net_iface(&iface), "test-client");
+	cr_end();
+}
+
+int main() {
+	struct hostclock clock_monotonic = {
+		.clock_id = CLOCK_MONOTONIC,
+	};
+	bootclock = lo_box_hostclock_as_alarmclock(&clock_monotonic);
+
+	coroutine_add("dhcp", dhcp_cr, NULL);
+	coroutine_main();
+	return 0;
+}