tidy

1 files changed, 70 insertions, 107 deletions

diff --git a/libdhcp/dhcp_client.c b/libdhcp/dhcp_client.c
index ff9a0e9..d4c849c 100644
--- a/libdhcp/dhcp_client.c
+++ b/libdhcp/dhcp_client.c
@@ -116,7 +116,6 @@
 	#define CONFIG_DHCP_CAN_RECV_UNICAST_IP_WITHOUT_IP      false
 #endif
 
-
 /* Implementation *************************************************************/
 
 #if CONFIG_DHCP_DEBUG
@@ -126,18 +125,6 @@
 	#define debugf(fmt, ...) ((void)0)
 #endif
 
-#define mem_encode(dst, obj) ({           \
-	typeof(obj) _obj = obj;           \
-	memcpy(dst, &_obj, sizeof(_obj)); \
-	sizeof(_obj);                     \
-})
-
-static inline size_t strn_encode(void *dst, char *str, size_t n) {
-	size_t len = strnlen(str, n);
-	memcpy(dst, str, len);
-	return len;
-}
-
 enum requirement {
 	MUST,
 	MUST_NOT,
@@ -145,7 +132,7 @@ enum requirement {
 	SHOULD_NOT,
 	MAY,
 
-	IT_DEPENDS,
+	_SHOULD_NOT_HAPPEN,
 };
 
 struct dhcp_client {
@@ -155,7 +142,7 @@ struct dhcp_client {
 	struct net_eth_addr              self_eth_addr;
 	char                             self_hostname[63];
 
-	/* Lease.  */
+	/* Mutable.  */
 	enum {
 		STATE_INIT,
 		STATE_SELECTING,
@@ -166,7 +153,8 @@ struct dhcp_client {
 
 		STATE_INIT_REBOOT,
 		STATE_REBOOTING,
-	} state;
+	}                                state;
+	uint8_t                          last_sent_msgtyp;
 	/* Lifetime of xid:
 	 * 1. initial      : [INIT]->DHCPDISCOVER->DHCPOFFER->DHCPREQUEST-+->DHCPNAK-------------->[INIT]
 	 *                                                                |->DHCPACK->DHCPDECLINE->[INIT]
@@ -197,13 +185,10 @@ struct dhcp_client {
  * @param client->lease_server_id (sometimes)
  * @param client->sock
  *
+ * @return client->last_sent_msgtyp
  * @return whether there was an error
  */
 static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *errstr) {
-	struct dhcp_msg msg = {0};
-	size_t optlen = 0;
-	bool server_broadcasts, client_broadcasts;
-
 	/**********************************************************************\
 	 * Preconditions                                                      *
 	\**********************************************************************/
@@ -219,20 +204,18 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 		       client->state == STATE_INIT_REBOOT || /* variant initial selection */
 		       client->state == STATE_BOUND       || /* T1 expired, start renew */
 		       client->state == STATE_RENEWING    ); /* T2 expired, start rebind */
-#define IMPOSSIBLE_REQUEST_CASES \
-	case STATE_INIT: \
-	case STATE_REQUESTING: \
-	case STATE_REBINDING: \
-	case STATE_REBOOTING: \
-		assert(msgtyp == DHCP_MSGTYP_REQUEST); \
-		assert_notreached("invalid client state for sending DHCPREQUEST"); \
-	default: \
-		assert_notreached("invalid client state");
+#define IMPOSSIBLE_REQUEST_STATES \
+		     STATE_INIT: \
+		case STATE_REQUESTING: \
+		case STATE_REBINDING: \
+		case STATE_REBOOTING
 
 	/**********************************************************************\
 	 * Setup                                                              *
 	\**********************************************************************/
 
+	bool server_broadcasts, client_broadcasts;
+
 	server_broadcasts = !CONFIG_DHCP_CAN_RECV_UNICAST_IP_WITHOUT_IP;
 	if (msgtyp == DHCP_MSGTYP_REQUEST &&
 	    (client->state == STATE_BOUND || client->state == STATE_RENEWING))
@@ -249,9 +232,14 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 	}
 
 	/**********************************************************************\
-	 * Table at https://datatracker.ietf.org/doc/html/rfc2131#page-37     *
+	 * Build the message                                                  *
 	\**********************************************************************/
 
+	struct dhcp_msg msg = {0};
+	size_t optlen = 0;
+
+	/* Base structure.
+	 * https://datatracker.ietf.org/doc/html/rfc2131#page-37 */
 	msg.op     = DHCP_OP_BOOTREQUEST;
 	msg.htype  = DHCP_HTYPE_ETHERNET;
 	msg.hlen   = sizeof(client->self_eth_addr);
@@ -280,7 +268,10 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 			 * DHCPREQUEST is never sent in the REBINDING
 			 * state.  */
 		                   msg.ciaddr = client->lease_client_addr; break;
-		IMPOSSIBLE_REQUEST_CASES
+		case IMPOSSIBLE_REQUEST_STATES:
+			assert_notreached("invalid client state for sending DHCPREQUEST");
+		default:
+			assert_notreached("invalid client state");
 		}                                                          break;
 	case DHCP_MSGTYP_DECLINE:  msg.ciaddr = net_ip4_addr_zero;         break;
 	case DHCP_MSGTYP_RELEASE:  msg.ciaddr = client->lease_client_addr; break;
@@ -288,49 +279,61 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 	msg.yiaddr = net_ip4_addr_zero; /* only set by servers */
 	msg.siaddr = net_ip4_addr_zero; /* only set by servers */
 	msg.giaddr = net_ip4_addr_zero; /* only set by relays */
-	mem_encode(msg.chaddr, client->self_eth_addr);
+	memcpy(msg.chaddr, client->self_eth_addr.octets, sizeof(client->self_eth_addr));
 	/* msg.sname = "options, if indicated in 'sname/file' option'; otherwise unused"; */
 	/* msg.file  = "options, if indicated in 'sname/file' option'; otherwise unused"; */
 
-	/**********************************************************************\
-	 * https://datatracker.ietf.org/doc/html/rfc2131#section-4.1          *
-	\**********************************************************************/
-
+	/* Magic cookie.
+	 * https://datatracker.ietf.org/doc/html/rfc2131#section-4.1 */
 	msg.options[optlen++] = dhcp_magic_cookie[0];
 	msg.options[optlen++] = dhcp_magic_cookie[1];
 	msg.options[optlen++] = dhcp_magic_cookie[2];
 	msg.options[optlen++] = dhcp_magic_cookie[3];
 
-	/**********************************************************************\
-	 * Table at https://datatracker.ietf.org/doc/html/rfc2131#page-38     *
-	\**********************************************************************/
-
-#define V(x) sizeof(x), &(x)
-#define NONE 0, NULL
-
+	/* Options.  */
 	static uint8_t parameter_request_list[] = {
 		DHCP_OPT_SUBNET_MASK,
 		DHCP_OPT_ROUTER,
 		DHCP_OPT_RENEWAL_TIME,
 		DHCP_OPT_REBINDING_TIME,
 	};
-
 	const struct {
 		bool                    have_cols;
 		enum requirement        cols[5];
 		size_t                  val_len;
 		void                   *val_ptr;
 	} options[0x100] = {
-		/* https://datatracker.ietf.org/doc/html/rfc2131#page-38 */
+#define V(x) sizeof(x), &(x)
+#define NONE 0, NULL
+		/* Encode the table from
+		 * https://datatracker.ietf.org/doc/html/rfc2131#page-38 */
+#define INC_ADDR ({                                                                             \
+			enum requirement req;                                                   \
+			switch (client->state) {                                                \
+			case STATE_SELECTING: case STATE_INIT_REBOOT: req = MUST;     break;    \
+			case STATE_BOUND: case STATE_RENEWING:        req = MUST_NOT; break;    \
+			case IMPOSSIBLE_REQUEST_STATES: default:      req = _SHOULD_NOT_HAPPEN; \
+			}                                                                       \
+			req;                                                                    \
+		})
+#define INC_SERVER ({                                                                                            \
+			enum requirement req;                                                                    \
+			switch (client->state) {                                                                 \
+			case STATE_SELECTING:                                          req = MUST;     break;    \
+			case STATE_INIT_REBOOT: case STATE_BOUND: case STATE_RENEWING: req = MUST_NOT; break;    \
+			case IMPOSSIBLE_REQUEST_STATES: default:                       req = _SHOULD_NOT_HAPPEN; \
+			}                                                                                        \
+			req;                                                                                     \
+		})
 		/* Option                             DISCOVER    INFORM      REQUEST     DECLINE   RELEASE */
 		/* ------                             ----------  ----------  ----------  --------  -------- */
-		[DHCP_OPT_ADDRESS_REQUEST]   = { 1, { MAY,        MUST_NOT,   IT_DEPENDS, MUST,     MUST_NOT }, V(client->lease_client_addr) },
+		[DHCP_OPT_ADDRESS_REQUEST]   = { 1, { MAY,        MUST_NOT,   INC_ADDR,   MUST,     MUST_NOT }, V(client->lease_client_addr) },
 		[DHCP_OPT_ADDRESS_TIME]      = { 1, { MAY,        MUST_NOT,   MAY,        MUST_NOT, MUST_NOT }, NONE },
 		[DHCP_OPT_OVERLOAD]          = { 1, { MAY,        MAY,        MAY,        MAY,      MAY      }, NONE },
 		[DHCP_OPT_DHCP_MSG_TYPE]     = { 1, { MUST,       MUST,       MUST,       MUST,     MUST     }, V(msgtyp) },
 		[DHCP_OPT_CLIENT_ID]         = { 1, { MAY,        MAY,        MAY,        MAY,      MAY      }, NONE },
 		[DHCP_OPT_CLASS_ID]          = { 1, { MAY,        MAY,        MAY,        MUST_NOT, MUST_NOT }, NONE },
-		[DHCP_OPT_DHCP_SERVER_ID]    = { 1, { MUST_NOT,   MUST_NOT,   IT_DEPENDS, MUST,     MUST     }, V(client->lease_server_id) },
+		[DHCP_OPT_DHCP_SERVER_ID]    = { 1, { MUST_NOT,   MUST_NOT,   INC_SERVER, MUST,     MUST     }, V(client->lease_server_id) },
 		[DHCP_OPT_PARAMETER_LIST]    = { 1, { MAY,        MAY,        MAY,        MUST_NOT, MUST_NOT }, V(parameter_request_list) },
 		[DHCP_OPT_DHCP_MAX_MSG_SIZE] = { 1, { MAY,        MAY,        MAY,        MUST_NOT, MUST_NOT },
 		                                 CONFIG_DHCP_OPT_SIZE > DHCP_MSG_MIN_MAX_OPT_SIZE ? 2 : 0,
@@ -355,37 +358,6 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 		enum requirement req = options[opt].have_cols
 			? options[opt].cols[col]
 			: options[0].cols[col];
-		if (req == IT_DEPENDS) {
-			switch (opt) {
-			case DHCP_OPT_ADDRESS_REQUEST:
-				assert(msgtyp == DHCP_MSGTYP_REQUEST);
-				switch (client->state) {
-				case STATE_SELECTING: case STATE_INIT_REBOOT:
-					req = MUST;
-					break;
-				case STATE_BOUND: case STATE_RENEWING:
-					req = MUST_NOT;
-					break;
-				IMPOSSIBLE_REQUEST_CASES
-				}
-				break;
-			case DHCP_OPT_DHCP_SERVER_ID:
-				assert(msgtyp == DHCP_MSGTYP_REQUEST);
-				switch (client->state) {
-				case STATE_SELECTING:
-					req = MUST;
-					break;
-				case STATE_INIT_REBOOT: case STATE_BOUND: case STATE_RENEWING:
-					req = MUST_NOT;
-					break;
-				IMPOSSIBLE_REQUEST_CASES
-				}
-				break;
-			default:
-				assert_notreached("unexpected IT_DEPENDS");
-			}
-			assert(req != IT_DEPENDS);
-		}
 		switch (req) {
 		case MUST_NOT:
 			/* Do nothing.  */
@@ -404,37 +376,35 @@ static bool dhcp_client_send(struct dhcp_client *client, uint8_t msgtyp, char *e
 				optlen += options[opt].val_len;
 			}
 			break;
-		case IT_DEPENDS:
-			assert_notreached("IT_DEPENDS should have been translated already");
+		case _SHOULD_NOT_HAPPEN:
+			assert_notreached("bad table");
 		}
 	}
-
-	/**********************************************************************\
-	 * https://datatracker.ietf.org/doc/html/rfc2131#section-4.1          *
-	\**********************************************************************/
-
 	msg.options[optlen++] = DHCP_OPT_END;
 	assert(optlen <= CONFIG_DHCP_OPT_SIZE);
 
-	/* Send.  */
+	/**********************************************************************\
+	 * Send                                                               *
+	\**********************************************************************/
 	ssize_t r = VCALL(client->sock, sendto, &msg, DHCP_MSG_BASE_SIZE + optlen,
 	                  client_broadcasts ? net_ip4_addr_broadcast : client->lease_server_id, DHCP_PORT_SERVER);
 	if (r < 0) {
 		debugf("error: sendto: %zd", r);
 		return true;
 	}
+	client->last_sent_msgtyp = msgtyp;
 	return false;
 }
 
 struct dhcp_recv_msg {
-	struct dhcp_msg                  raw;
+	struct dhcp_msg		raw;
 	struct {
-		uint16_t                         len;
-		uint8_t                         *dat;
-	}                                options[0x100];
-	uint8_t                          _option_data[sizeof((struct dhcp_msg){}.options)+
-	                                              sizeof((struct dhcp_msg){}.file)+
-	                                              sizeof((struct dhcp_msg){}.sname)];
+		uint16_t                len;
+		uint8_t                *dat;
+	}                       options[0x100];
+	uint8_t                 _option_data[sizeof((struct dhcp_msg){}.options)+
+	                                     sizeof((struct dhcp_msg){}.file)+
+	                                     sizeof((struct dhcp_msg){}.sname)];
 };
 
 /** @return whether there is an error */
@@ -587,15 +557,17 @@ static ssize_t dhcp_client_recv(struct dhcp_client *client, struct dhcp_recv_msg
 	if (optoverload & 2u)
 		_dhcp_client_recv_consolidate_opts(ret, ret->raw.sname, sizeof(ret->raw.sname));
 	/* Validate presence of options.  */
-	static const struct {
+	const struct {
 		bool                    have_cols;
 		enum requirement        cols[3];
 	} option_req[0x100] = {
-		/* https://datatracker.ietf.org/doc/html/rfc2131#page-29 */
+		/* Enocde the table from
+		 * https://datatracker.ietf.org/doc/html/rfc2131#page-29 */
+#define REQ_TIME client->last_sent_msgtyp == DHCP_MSGTYP_REQUEST ? MUST : MUST_NOT
 		/* Option                             DHCPOFFER DHCPACK     DHCPNAK */
 		/* ------                             --------  ----------  -------- */
 		[DHCP_OPT_ADDRESS_REQUEST]   = { 1, { MUST_NOT, MUST_NOT,   MUST_NOT } },
-		[DHCP_OPT_ADDRESS_TIME]      = { 1, { MUST,     IT_DEPENDS, MUST_NOT } },
+		[DHCP_OPT_ADDRESS_TIME]      = { 1, { MUST,     REQ_TIME,   MUST_NOT } },
 		[DHCP_OPT_OVERLOAD]          = { 1, { MAY,      MAY,        MUST_NOT } },
 		[DHCP_OPT_DHCP_MSG_TYPE]     = { 1, { MUST,     MUST,       MUST     } },
 		[DHCP_OPT_PARAMETER_LIST]    = { 1, { MUST_NOT, MUST_NOT,   MUST_NOT } },
@@ -619,15 +591,6 @@ static ssize_t dhcp_client_recv(struct dhcp_client *client, struct dhcp_recv_msg
 		enum requirement req = option_req[opt].have_cols
 			? option_req[opt].cols[col]
 			: option_req[0].cols[col];
-		if (req == IT_DEPENDS) {
-			/* "MUST" when this is a response to a DHCPREQUEST,
-			 * "MUST_NOT" when this is a response to a DHCPINFORM.
-			 * Because this client implementation never sends
-			 * DHCPINFORM, this must be a response to
-			 * DHCPREQUEST.  */
-			req = MUST;
-			assert(req != IT_DEPENDS);
-		}
 		switch (req) {
 		case MUST:
 			if (!ret->options[opt].len)
@@ -642,8 +605,8 @@ static ssize_t dhcp_client_recv(struct dhcp_client *client, struct dhcp_recv_msg
 		case MAY:
 			/* Do nothing.  */
 			break;
-		case IT_DEPENDS:
-			assert_notreached("IT_DEPENDS should have been translated already");
+		case _SHOULD_NOT_HAPPEN:
+			assert_notreached("bad table");
 		}
 	}