dhcp: heed TODO item - divorced options from their string descriptions

code shrink while at it.

function                                             old     new   delta
dhcp_option_strings                                    -     258    +258
udhcp_run_script                                    1135    1174     +39
dhcp_option_lengths                                    -      11     +11
udhcp_add_simple_option                               93      92      -1
packet_num                                             4       -      -4
read_opt                                             746     739      -7
udhcp_option_lengths                                  11       -     -11
udhcpc_main                                         2590    2494     -96
dhcp_options                                         490      70    -420
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 1/4 up/down: 308/-539)         Total: -231 bytes
   text    data     bss     dec     hex filename
 775309     929    9100  785338   bfbba busybox_old
 775098     929    9084  785111   bfad7 busybox_unstripped

8 files changed, 135 insertions, 88 deletions

diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index eecb72c..55782b5 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -77,7 +77,6 @@ void udhcp_run_script(struct dhcpMessage *packet, const char *name);
 #define end_option		udhcp_end_option
 #define add_option_string	udhcp_add_option_string
 #define add_simple_option	udhcp_add_simple_option
-#define option_lengths		udhcp_option_lengths
 /* from socket.h */
 #define listen_socket		udhcp_listen_socket
 #define read_interface		udhcp_read_interface
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 6ade1ee..d8077f7 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -19,15 +19,9 @@
 #include "options.h"
 
 
-/* Something is definitely wrong here. IPv4 addresses
- * in variables of type long?? BTW, we use inet_ntoa()
- * in the code. Manpage says that struct in_addr has a member of type long (!)
- * which holds IPv4 address, and the struct is passed by value (!!)
- */
 static int timeout; /* = 0. Must be signed */
 static uint32_t requested_ip; /* = 0 */
 static uint32_t server_addr;
-static int packet_num; /* = 0 */
 static int sockfd = -1;
 
 #define LISTEN_NONE 0
@@ -74,12 +68,6 @@ static void perform_renew(void)
 	case INIT_SELECTING:
 		break;
 	}
-
-	/* start things over */
-	packet_num = 0;
-
-	/* Kill any timeouts because the user wants this to hurry along */
-	timeout = 0;
 }
 
 
@@ -153,8 +141,11 @@ int udhcpc_main(int argc, char **argv)
 	int discover_retries = 3;
 	uint32_t xid = 0;
 	uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
-	unsigned t1 = 0, t2 = 0; /* what a wonderful names */
-	unsigned timestamp_got_lease = 0; /* for gcc */
+	int packet_num;
+	/* t1, t2... what a wonderful names... */
+	unsigned t1 = t1; /* for gcc */
+	unsigned t2 = t2;
+	unsigned timestamp_got_lease = timestamp_got_lease;
 	unsigned opt;
 	int max_fd;
 	int retval;
@@ -315,6 +306,7 @@ int udhcpc_main(int argc, char **argv)
 	state = INIT_SELECTING;
 	udhcp_run_script(NULL, "deconfig");
 	change_listen_mode(LISTEN_RAW);
+	packet_num = 0;
 
 	/* Main event loop. select() waits on signal pipe and possibly
 	 * on sockfd.
@@ -585,6 +577,10 @@ int udhcpc_main(int argc, char **argv)
 			switch (signo) {
 			case SIGUSR1:
 				perform_renew();
+				/* start things over */
+				packet_num = 0;
+				/* Kill any timeouts because the user wants this to hurry along */
+				timeout = 0;
 				break;
 			case SIGUSR2:
 				perform_release();
diff --git a/networking/udhcp/dhcpd.h b/networking/udhcp/dhcpd.h
index 28106d3..216b7ab 100644
--- a/networking/udhcp/dhcpd.h
+++ b/networking/udhcp/dhcpd.h
@@ -100,7 +100,7 @@ int send_inform(struct dhcpMessage *oldpacket);
 int read_config(const char *file);
 void write_leases(void);
 void read_leases(const char *file);
-struct option_set *find_option(struct option_set *opt_list, char code);
+struct option_set *find_option(struct option_set *opt_list, uint8_t code);
 
 
 #endif
diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c
index 5026598..63c9064 100644
--- a/networking/udhcp/files.c
+++ b/networking/udhcp/files.c
@@ -71,7 +71,7 @@ static int read_yn(const char *line, void *arg)
 
 
 /* find option 'code' in opt_list */
-struct option_set *find_option(struct option_set *opt_list, char code)
+struct option_set *find_option(struct option_set *opt_list, uint8_t code)
 {
 	while (opt_list && opt_list->data[OPT_CODE] < code)
 		opt_list = opt_list->next;
@@ -154,31 +154,29 @@ static int read_opt(const char *const_line, void *arg)
 {
 	struct option_set **opt_list = arg;
 	char *opt, *val, *endptr;
-	const struct dhcp_option *option;
-	int retval = 0, length;
-	char buffer[8];
 	char *line;
+	const struct dhcp_option *option;
+	int retval, length, idx;
+	char buffer[8] __attribute__((aligned(4)));
 	uint16_t *result_u16 = (uint16_t *) buffer;
 	uint32_t *result_u32 = (uint32_t *) buffer;
 
 	/* Cheat, the only const line we'll actually get is "" */
 	line = (char *) const_line;
 	opt = strtok(line, " \t=");
-	if (!opt) return 0;
+	if (!opt)
+		return 0;
 
-	option = dhcp_options;
-	while (1) {
-		if (!option->code)
-			return 0;
-		if (!strcasecmp(option->opt_name, opt))
-			break;
-		option++;
-	}
+	idx = index_in_strings(opt, dhcp_option_strings); /* NB: was strcasecmp! */
+	if (idx < 0)
+		return 0;
+	option = &dhcp_options[idx];
 
+	retval = 0;
 	do {
 		val = strtok(NULL, ", \t");
 		if (!val) break;
-		length = option_lengths[option->flags & TYPE_MASK];
+		length = dhcp_option_lengths[option->flags & TYPE_MASK];
 		retval = 0;
 		opt = buffer; /* new meaning for variable opt */
 		switch (option->flags & TYPE_MASK) {
diff --git a/networking/udhcp/leases.c b/networking/udhcp/leases.c
index 60e9edc..1745fee 100644
--- a/networking/udhcp/leases.c
+++ b/networking/udhcp/leases.c
@@ -98,7 +98,9 @@ struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr)
 /* check is an IP is taken, if it is, add it to the lease table */
 static int nobody_responds_to_arp(uint32_t addr)
 {
-	static const uint8_t blank_chaddr[16]; /* 16 zero bytes */
+	/* 16 zero bytes */
+	static const uint8_t blank_chaddr[16] = { 0 };
+	/* = { 0 } helps gcc to put it in rodata, not bss */
 
 	struct in_addr temp;
 	int r;
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index ffc0ed1..c224f36 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -11,54 +11,97 @@
 
 /* Supported options are easily added here */
 const struct dhcp_option dhcp_options[] = {
-	/* opt_name[12] flags                                   code */
-	{"subnet",      OPTION_IP | OPTION_REQ,                 0x01},   /* DHCP_SUBNET         */
-	{"timezone",    OPTION_S32,                             0x02},   /* DHCP_TIME_OFFSET    */
-	{"router",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x03},   /* DHCP_ROUTER         */
-	{"timesvr",     OPTION_IP | OPTION_LIST,                0x04},   /* DHCP_TIME_SERVER    */
-	{"namesvr",     OPTION_IP | OPTION_LIST,                0x05},   /* DHCP_NAME_SERVER    */
-	{"dns",         OPTION_IP | OPTION_LIST | OPTION_REQ,   0x06},   /* DHCP_DNS_SERVER     */
-	{"logsvr",      OPTION_IP | OPTION_LIST,                0x07},   /* DHCP_LOG_SERVER     */
-	{"cookiesvr",   OPTION_IP | OPTION_LIST,                0x08},   /* DHCP_COOKIE_SERVER  */
-	{"lprsvr",      OPTION_IP | OPTION_LIST,                0x09},   /* DHCP_LPR_SERVER     */
-	{"hostname",    OPTION_STRING | OPTION_REQ,             0x0c},   /* DHCP_HOST_NAME      */
-	{"bootsize",    OPTION_U16,                             0x0d},   /* DHCP_BOOT_SIZE      */
-	{"domain",      OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f}, /* DHCP_DOMAIN_NAME    */
-	{"swapsvr",     OPTION_IP,                              0x10},   /* DHCP_SWAP_SERVER    */
-	{"rootpath",    OPTION_STRING,                          0x11},   /* DHCP_ROOT_PATH      */
-	{"ipttl",       OPTION_U8,                              0x17},   /* DHCP_IP_TTL         */
-	{"mtu",         OPTION_U16,                             0x1a},   /* DHCP_MTU            */
-	{"broadcast",   OPTION_IP | OPTION_REQ,                 0x1c},   /* DHCP_BROADCAST      */
-	{"nisdomain",   OPTION_STRING | OPTION_REQ,             0x28},   /* DHCP_NTP_SERVER     */
-	{"nissrv",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x29},   /* DHCP_WINS_SERVER    */
-	{"ntpsrv",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x2a},   /* DHCP_REQUESTED_IP   */
-	{"wins",        OPTION_IP | OPTION_LIST,                0x2c},   /* DHCP_LEASE_TIME     */
-	{"requestip",   OPTION_IP,                              0x32},   /* DHCP_OPTION_OVER    */
-	{"lease",       OPTION_U32,                             0x33},   /* DHCP_MESSAGE_TYPE   */
-	{"dhcptype",    OPTION_U8,                              0x35},   /* DHCP_SERVER_ID      */
-	{"serverid",    OPTION_IP,                              0x36},   /* DHCP_PARAM_REQ      */
-	{"message",     OPTION_STRING,                          0x38},   /* DHCP_MESSAGE        */
-// TODO: 1) some options should not be parsed & passed to script -
-// maxsize sure should not, since it cannot appear in server responses!
-// grep for opt_name is fix the mess.
-// 2) Using fixed-sized char[] vector wastes space.
-	{"maxsize",     OPTION_U16,                             0x39},   /* DHCP_MAX_SIZE       */
-	{"vendorclass", OPTION_STRING,                          0x3C},   /* DHCP_VENDOR         */
-	{"clientid",    OPTION_STRING,                          0x3D},   /* DHCP_CLIENT_ID      */
-	{"tftp",        OPTION_STRING,                          0x42},
-	{"bootfile",    OPTION_STRING,                          0x43},
-	{"userclass",   OPTION_STRING,                          0x4D},
+	/* flags                                     code */
+	{ OPTION_IP | OPTION_REQ,                    0x01 }, /* DHCP_SUBNET        */
+	{ OPTION_S32,                                0x02 }, /* DHCP_TIME_OFFSET   */
+	{ OPTION_IP | OPTION_LIST | OPTION_REQ,      0x03 }, /* DHCP_ROUTER        */
+	{ OPTION_IP | OPTION_LIST,                   0x04 }, /* DHCP_TIME_SERVER   */
+	{ OPTION_IP | OPTION_LIST,                   0x05 }, /* DHCP_NAME_SERVER   */
+	{ OPTION_IP | OPTION_LIST | OPTION_REQ,      0x06 }, /* DHCP_DNS_SERVER    */
+	{ OPTION_IP | OPTION_LIST,                   0x07 }, /* DHCP_LOG_SERVER    */
+	{ OPTION_IP | OPTION_LIST,                   0x08 }, /* DHCP_COOKIE_SERVER */
+	{ OPTION_IP | OPTION_LIST,                   0x09 }, /* DHCP_LPR_SERVER    */
+	{ OPTION_STRING | OPTION_REQ,                0x0c }, /* DHCP_HOST_NAME     */
+	{ OPTION_U16,                                0x0d }, /* DHCP_BOOT_SIZE     */
+	{ OPTION_STRING | OPTION_LIST | OPTION_REQ,  0x0f }, /* DHCP_DOMAIN_NAME   */
+	{ OPTION_IP,                                 0x10 }, /* DHCP_SWAP_SERVER   */
+	{ OPTION_STRING,                             0x11 }, /* DHCP_ROOT_PATH     */
+	{ OPTION_U8,                                 0x17 }, /* DHCP_IP_TTL        */
+	{ OPTION_U16,                                0x1a }, /* DHCP_MTU           */
+	{ OPTION_IP | OPTION_REQ,                    0x1c }, /* DHCP_BROADCAST     */
+	{ OPTION_STRING | OPTION_REQ,                0x28 }, /* DHCP_NTP_SERVER    */
+	{ OPTION_IP | OPTION_LIST | OPTION_REQ,      0x29 }, /* DHCP_WINS_SERVER   */
+	{ OPTION_IP | OPTION_LIST | OPTION_REQ,      0x2a }, /* DHCP_REQUESTED_IP  */
+	{ OPTION_IP | OPTION_LIST,                   0x2c }, /* DHCP_LEASE_TIME    */
+	{ OPTION_IP,                                 0x32 }, /* DHCP_OPTION_OVER   */
+	{ OPTION_U32,                                0x33 }, /* DHCP_MESSAGE_TYPE  */
+	{ OPTION_U8,                                 0x35 }, /* DHCP_SERVER_ID     */
+	{ OPTION_IP,                                 0x36 }, /* DHCP_PARAM_REQ     */
+	{ OPTION_STRING,                             0x38 }, /* DHCP_MESSAGE       */
+	{ OPTION_STRING,                             0x3C }, /* DHCP_VENDOR        */
+	{ OPTION_STRING,                             0x3D }, /* DHCP_CLIENT_ID     */
+	{ OPTION_STRING,                             0x42 }, /* "tftp"             */
+	{ OPTION_STRING,                             0x43 }, /* "bootfile"         */
+	{ OPTION_STRING,                             0x4D }, /* "userclass"        */
 #if ENABLE_FEATURE_RFC3397
-	{"search",      OPTION_STR1035 | OPTION_LIST | OPTION_REQ, 0x77},
+	{ OPTION_STR1035 | OPTION_LIST | OPTION_REQ, 0x77 }, /* "search"           */
 #endif
 	/* MSIE's "Web Proxy Autodiscovery Protocol" support */
-	{"wpad",        OPTION_STRING,                          0xfc},
-	{} /* zero-padded terminating entry */
+	{ OPTION_STRING,                             0xfc }, /* "wpad"             */
+
+	/* Options below have no match in dhcp_option_strings[],
+	 * are not passed to dhcpc scripts, and cannot be specified
+	 * with "option XXX YYY" syntax in dhcpd config file. */
+
+	{ OPTION_U16,                                0x39 }, /* DHCP_MAX_SIZE      */
+	{ } /* zeroed terminating entry */
 };
 
+/* Used for converting options from incoming packets to env variables
+ * for udhcpc stript */
+/* Must match dhcp_options[] order */
+const char dhcp_option_strings[] ALIGN1 =
+	"subnet" "\0"      /* DHCP_SUBNET         */
+	"timezone" "\0"    /* DHCP_TIME_OFFSET    */
+	"router" "\0"      /* DHCP_ROUTER         */
+	"timesvr" "\0"     /* DHCP_TIME_SERVER    */
+	"namesvr" "\0"     /* DHCP_NAME_SERVER    */
+	"dns" "\0"         /* DHCP_DNS_SERVER     */
+	"logsvr" "\0"      /* DHCP_LOG_SERVER     */
+	"cookiesvr" "\0"   /* DHCP_COOKIE_SERVER  */
+	"lprsvr" "\0"      /* DHCP_LPR_SERVER     */
+	"hostname" "\0"    /* DHCP_HOST_NAME      */
+	"bootsize" "\0"    /* DHCP_BOOT_SIZE      */
+	"domain" "\0"      /* DHCP_DOMAIN_NAME    */
+	"swapsvr" "\0"     /* DHCP_SWAP_SERVER    */
+	"rootpath" "\0"    /* DHCP_ROOT_PATH      */
+	"ipttl" "\0"       /* DHCP_IP_TTL         */
+	"mtu" "\0"         /* DHCP_MTU            */
+	"broadcast" "\0"   /* DHCP_BROADCAST      */
+	"nisdomain" "\0"   /* DHCP_NTP_SERVER     */
+	"nissrv" "\0"      /* DHCP_WINS_SERVER    */
+	"ntpsrv" "\0"      /* DHCP_REQUESTED_IP   */
+	"wins" "\0"        /* DHCP_LEASE_TIME     */
+	"requestip" "\0"   /* DHCP_OPTION_OVER    */
+	"lease" "\0"       /* DHCP_MESSAGE_TYPE   */
+	"dhcptype" "\0"    /* DHCP_SERVER_ID      */
+	"serverid" "\0"    /* DHCP_PARAM_REQ      */
+	"message" "\0"     /* DHCP_MESSAGE        */
+	"vendorclass" "\0" /* DHCP_VENDOR         */
+	"clientid" "\0"    /* DHCP_CLIENT_ID      */
+	"tftp" "\0"
+	"bootfile" "\0"
+	"userclass" "\0"
+#if ENABLE_FEATURE_RFC3397
+	"search" "\0"
+#endif
+	/* MSIE's "Web Proxy Autodiscovery Protocol" support */
+	"wpad" "\0"
+	;
+
 
 /* Lengths of the different option types */
-const unsigned char option_lengths[] ALIGN1 = {
+const uint8_t dhcp_option_lengths[] ALIGN1 = {
 	[OPTION_IP] =      4,
 	[OPTION_IP_PAIR] = 8,
 	[OPTION_BOOLEAN] = 1,
@@ -137,8 +180,10 @@ int end_option(uint8_t *optionptr)
 	int i = 0;
 
 	while (optionptr[i] != DHCP_END) {
-		if (optionptr[i] == DHCP_PADDING) i++;
-		else i += optionptr[i + OPT_LEN] + 2;
+		if (optionptr[i] == DHCP_PADDING)
+			i++;
+		else
+			i += optionptr[i + OPT_LEN] + 2;
 	}
 	return i;
 }
@@ -173,10 +218,11 @@ int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
 			uint8_t option[6], len;
 
 			option[OPT_CODE] = code;
-			len = option_lengths[dh->flags & TYPE_MASK];
+			len = dhcp_option_lengths[dh->flags & TYPE_MASK];
 			option[OPT_LEN] = len;
-			if (BB_BIG_ENDIAN) data <<= 8 * (4 - len);
-			/* This memcpy is for broken processors which can't
+			if (BB_BIG_ENDIAN)
+				data <<= 8 * (4 - len);
+			/* This memcpy is for processors which can't
 			 * handle a simple unaligned 32-bit assignment */
 			memcpy(&option[OPT_DATA], &data, 4);
 			return add_option_string(optionptr, option);
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 4bf73a1..c98aec4 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -98,13 +98,13 @@ enum {
 #define OPT_DATA 2
 
 struct dhcp_option {
-	char opt_name[12];
-	char flags;
+	uint8_t flags;
 	uint8_t code;
 };
 
 extern const struct dhcp_option dhcp_options[];
-extern const unsigned char option_lengths[];
+extern const char dhcp_option_strings[];
+extern const uint8_t dhcp_option_lengths[];
 
 uint8_t *get_option(struct dhcpMessage *packet, int code);
 int end_option(uint8_t *optionptr);
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 33d96e6..8a18898 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -33,7 +33,7 @@ static const uint8_t max_option_length[] = {
 static inline int upper_length(int length, int opt_index)
 {
 	return max_option_length[opt_index] *
-		(length / option_lengths[opt_index]);
+		(length / dhcp_option_lengths[opt_index]);
 }
 
 
@@ -57,7 +57,7 @@ static int mton(uint32_t mask)
 
 
 /* Allocate and fill with the text of option 'option'. */
-static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p)
+static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
 {
 	int len, type, optlen;
 	uint16_t val_u16;
@@ -68,10 +68,10 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p)
 
 	len = option[OPT_LEN - 2];
 	type = type_p->flags & TYPE_MASK;
-	optlen = option_lengths[type];
+	optlen = dhcp_option_lengths[type];
 
-	dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->opt_name) + 2);
-	dest += sprintf(ret, "%s=", type_p->opt_name);
+	dest = ret = xmalloc(upper_length(len, type) + strlen(opt_name) + 2);
+	dest += sprintf(ret, "%s=", opt_name);
 
 	for (;;) {
 		switch (type) {
@@ -133,6 +133,7 @@ static char **fill_envp(struct dhcpMessage *packet)
 	int i, j;
 	char **envp;
 	char *var;
+	const char *opt_name;
 	uint8_t *temp;
 	char over = 0;
 
@@ -171,11 +172,13 @@ static char **fill_envp(struct dhcpMessage *packet)
 	envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
 	sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
 
-	for (i = 0; dhcp_options[i].code; i++) {
+	opt_name = dhcp_option_strings;
+	i = 0;
+	while (*opt_name) {
 		temp = get_option(packet, dhcp_options[i].code);
 		if (!temp)
-			continue;
-		envp[j++] = alloc_fill_opts(temp, &dhcp_options[i]);
+			goto next;
+		envp[j++] = alloc_fill_opts(temp, &dhcp_options[i], opt_name);
 
 		/* Fill in a subnet bits option for things like /24 */
 		if (dhcp_options[i].code == DHCP_SUBNET) {
@@ -183,6 +186,9 @@ static char **fill_envp(struct dhcpMessage *packet)
 			memcpy(&subnet, temp, 4);
 			envp[j++] = xasprintf("mask=%d", mton(subnet));
 		}
+ next:
+		opt_name += strlen(opt_name) + 1;
+		i++;
 	}
 	if (packet->siaddr) {
 		envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));