dhcpc: let server know we don't like oversized packets.

add TODO comment

6 files changed, 58 insertions, 47 deletions

diff --git a/networking/udhcp/Config.in b/networking/udhcp/Config.in
index 1aef69b..242a9f3 100644
--- a/networking/udhcp/Config.in
+++ b/networking/udhcp/Config.in
@@ -104,3 +104,4 @@ config UDHCPC_SLACK_FOR_BUGGY_SERVERS
 	    seems to confuse maximum allowed UDP packet size with
 	    maximum size of entire IP packet, and sends packets which are
 	    28 bytes too large.
+          Seednet (ISP) VDSL: sends packets 2 bytes too big.
diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c
index 4a5c627..406fe34 100644
--- a/networking/udhcp/clientpacket.c
+++ b/networking/udhcp/clientpacket.c
@@ -96,6 +96,9 @@ int send_discover(uint32_t xid, uint32_t requested)
 	if (requested)
 		add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
 
+	/* Explicitly saying that we want RFC-compliant packets helps
+	 * some buggy DHCP servers to NOT send bigger packets */
+	add_simple_option(packet.options, DHCP_MAX_SIZE, htons(576));
 	add_requests(&packet);
 	bb_info_msg("Sending discover...");
 	return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c
index 59a5e4a..5026598 100644
--- a/networking/udhcp/files.c
+++ b/networking/udhcp/files.c
@@ -90,7 +90,7 @@ static void attach_option(struct option_set **opt_list,
 
 	existing = find_option(*opt_list, option->code);
 	if (!existing) {
-		DEBUG("Attaching option %s to list", option->name);
+		DEBUG("Attaching option %02x to list", option->code);
 
 #if ENABLE_FEATURE_RFC3397
 		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
@@ -119,7 +119,7 @@ static void attach_option(struct option_set **opt_list,
 	}
 
 	/* add it to an existing option */
-	DEBUG("Attaching option %s to existing member of list", option->name);
+	DEBUG("Attaching option %02x to existing member of list", option->code);
 	if (option->flags & OPTION_LIST) {
 #if ENABLE_FEATURE_RFC3397
 		if ((option->flags & TYPE_MASK) == OPTION_STR1035)
@@ -170,7 +170,7 @@ static int read_opt(const char *const_line, void *arg)
 	while (1) {
 		if (!option->code)
 			return 0;
-		if (!strcasecmp(option->name, opt))
+		if (!strcasecmp(option->opt_name, opt))
 			break;
 		option++;
 	}
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 6744e2a..ffc0ed1 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -9,37 +9,42 @@
 #include "options.h"
 
 
-/* supported options are easily added here */
+/* Supported options are easily added here */
 const struct dhcp_option dhcp_options[] = {
-	/* name[12]     flags                                   code */
-	{"subnet",      OPTION_IP | OPTION_REQ,                 0x01},
-	{"timezone",    OPTION_S32,                             0x02},
-	{"router",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x03},
-	{"timesvr",     OPTION_IP | OPTION_LIST,                0x04},
-	{"namesvr",     OPTION_IP | OPTION_LIST,                0x05},
-	{"dns",         OPTION_IP | OPTION_LIST | OPTION_REQ,   0x06},
-	{"logsvr",      OPTION_IP | OPTION_LIST,                0x07},
-	{"cookiesvr",   OPTION_IP | OPTION_LIST,                0x08},
-	{"lprsvr",      OPTION_IP | OPTION_LIST,                0x09},
-	{"hostname",    OPTION_STRING | OPTION_REQ,             0x0c},
-	{"bootsize",    OPTION_U16,                             0x0d},
-	{"domain",      OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f},
-	{"swapsvr",     OPTION_IP,                              0x10},
-	{"rootpath",    OPTION_STRING,                          0x11},
-	{"ipttl",       OPTION_U8,                              0x17},
-	{"mtu",         OPTION_U16,                             0x1a},
-	{"broadcast",   OPTION_IP | OPTION_REQ,                 0x1c},
-	{"nisdomain",   OPTION_STRING | OPTION_REQ,             0x28},
-	{"nissrv",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x29},
-	{"ntpsrv",      OPTION_IP | OPTION_LIST | OPTION_REQ,   0x2a},
-	{"wins",        OPTION_IP | OPTION_LIST,                0x2c},
-	{"requestip",   OPTION_IP,                              0x32},
-	{"lease",       OPTION_U32,                             0x33},
-	{"dhcptype",    OPTION_U8,                              0x35},
-	{"serverid",    OPTION_IP,                              0x36},
-	{"message",     OPTION_STRING,                          0x38},
-	{"vendorclass", OPTION_STRING,                          0x3C},
-	{"clientid",    OPTION_STRING,                          0x3D},
+	/* 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},
@@ -48,9 +53,10 @@ const struct dhcp_option dhcp_options[] = {
 #endif
 	/* MSIE's "Web Proxy Autodiscovery Protocol" support */
 	{"wpad",        OPTION_STRING,                          0xfc},
-	{"",            0x00,                                   0x00}
+	{} /* zero-padded terminating entry */
 };
 
+
 /* Lengths of the different option types */
 const unsigned char option_lengths[] ALIGN1 = {
 	[OPTION_IP] =      4,
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 33a968c..4bf73a1 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -33,6 +33,7 @@ enum {
 
 #define DHCP_MAGIC		0x63825363
 
+
 /* DHCP option codes (partial list) */
 #define DHCP_PADDING		0x00
 #define DHCP_SUBNET		0x01
@@ -67,7 +68,6 @@ enum {
 #define DHCP_VENDOR		0x3c
 #define DHCP_CLIENT_ID		0x3d
 #define DHCP_FQDN		0x51
-
 #define DHCP_END		0xFF
 
 
@@ -98,7 +98,7 @@ enum {
 #define OPT_DATA 2
 
 struct dhcp_option {
-	char name[12];
+	char opt_name[12];
 	char flags;
 	uint8_t code;
 };
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 68de358..33d96e6 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -44,14 +44,15 @@ static int sprintip(char *dest, const char *pre, const uint8_t *ip)
 
 
 /* really simple implementation, just count the bits */
-static int mton(struct in_addr *mask)
+static int mton(uint32_t mask)
 {
-	int i;
-	unsigned long bits = ntohl(mask->s_addr);
-	/* too bad one can't check the carry bit, etc in c bit
-	 * shifting */
-	for (i = 0; i < 32 && !((bits >> i) & 1); i++);
-	return 32 - i;
+	int i = 0;
+	mask = ntohl(mask); /* 111110000-like bit pattern */
+	while (mask) {
+		i++;
+		mask <<= 1;
+	}
+	return i;
 }
 
 
@@ -69,8 +70,8 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p)
 	type = type_p->flags & TYPE_MASK;
 	optlen = option_lengths[type];
 
-	dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->name) + 2);
-	dest += sprintf(ret, "%s=", type_p->name);
+	dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->opt_name) + 2);
+	dest += sprintf(ret, "%s=", type_p->opt_name);
 
 	for (;;) {
 		switch (type) {
@@ -133,7 +134,6 @@ static char **fill_envp(struct dhcpMessage *packet)
 	char **envp;
 	char *var;
 	uint8_t *temp;
-	struct in_addr subnet;
 	char over = 0;
 
 	if (packet) {
@@ -179,8 +179,9 @@ static char **fill_envp(struct dhcpMessage *packet)
 
 		/* Fill in a subnet bits option for things like /24 */
 		if (dhcp_options[i].code == DHCP_SUBNET) {
+			uint32_t subnet;
 			memcpy(&subnet, temp, 4);
-			envp[j++] = xasprintf("mask=%d", mton(&subnet));
+			envp[j++] = xasprintf("mask=%d", mton(subnet));
 		}
 	}
 	if (packet->siaddr) {