dhcp: stop using magic constants; use (htonl(CONST) != a) - it's smaller

function                                             old     new   delta
udhcp_get_packet                                     146     134     -12
get_raw_packet                                       368     353     -15

5 files changed, 23 insertions, 19 deletions

diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c
index e7eeb58b1..4a5c627f4 100644
--- a/networking/udhcp/clientpacket.c
+++ b/networking/udhcp/clientpacket.c
@@ -171,7 +171,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd)
         bytes = read(fd, &packet, sizeof(struct udp_dhcp_packet));
         if (bytes < 0) {
                 DEBUG("Cannot read on raw listening socket - ignoring");
-                usleep(500000); /* possible down interface, looping condition */
+                sleep(1); /* possible down interface, looping condition */
                 return -1;
         }
 
@@ -190,7 +190,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd)
 
         /* Make sure its the right packet for us, and that it passes sanity checks */
         if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
-         || packet.ip.ihl != sizeof(packet.ip) >> 2
+         || packet.ip.ihl != (sizeof(packet.ip) >> 2)
          || packet.udp.dest != htons(CLIENT_PORT)
          || bytes > (int) sizeof(struct udp_dhcp_packet)
          || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
@@ -207,7 +207,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd)
                 return -1;
         }
 
-        /* verify the UDP checksum by replacing the header with a psuedo header */
+        /* verify the UDP checksum by replacing the header with a pseudo header */
         source = packet.ip.saddr;
         dest = packet.ip.daddr;
         check = packet.udp.check;
@@ -225,7 +225,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd)
 
         memcpy(payload, &(packet.data), bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
 
-        if (ntohl(payload->cookie) != DHCP_MAGIC) {
+        if (payload->cookie != htonl(DHCP_MAGIC)) {
                 bb_error_msg("received bogus message (bad magic) - ignoring");
                 return -2;
         }
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index 179c21fdb..4f2d31c98 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -38,12 +38,18 @@ struct dhcpMessage {
         uint8_t file[128];
         uint32_t cookie;
         uint8_t options[308]; /* 312 - cookie */
-};
+} ATTRIBUTE_PACKED;
 
 struct udp_dhcp_packet {
         struct iphdr ip;
         struct udphdr udp;
         struct dhcpMessage data;
+} ATTRIBUTE_PACKED;
+
+/* Let's see whether compiler understood us right */
+struct BUG_bad_sizeof_struct_udp_dhcp_packet {
+        char BUG_bad_sizeof_struct_udp_dhcp_packet
+                [sizeof(struct udp_dhcp_packet) != 576 ? -1 : 1];
 };
 
 void udhcp_init_header(struct dhcpMessage *packet, char type);
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 3168fc69a..2b4f1644f 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -73,12 +73,13 @@ uint8_t *get_option(struct dhcpMessage *packet, int code)
 {
         int i, length;
         uint8_t *optionptr;
-        int over = 0, done = 0, curr = OPTION_FIELD;
+        int over = 0;
+        int curr = OPTION_FIELD;
 
         optionptr = packet->options;
         i = 0;
-        length = 308;
-        while (!done) {
+        length = sizeof(packet->options);
+        while (1) {
                 if (i >= length) {
                         bb_error_msg("bogus packet, option fields too long");
                         return NULL;
@@ -103,17 +104,18 @@ uint8_t *get_option(struct dhcpMessage *packet, int code)
                         i += optionptr[OPT_LEN] + 2;
                         break;
                 case DHCP_END:
-                        if (curr == OPTION_FIELD && over & FILE_FIELD) {
+                        if (curr == OPTION_FIELD && (over & FILE_FIELD)) {
                                 optionptr = packet->file;
                                 i = 0;
-                                length = 128;
+                                length = sizeof(packet->file);
                                 curr = FILE_FIELD;
-                        } else if (curr == FILE_FIELD && over & SNAME_FIELD) {
+                        } else if (curr == FILE_FIELD && (over & SNAME_FIELD)) {
                                 optionptr = packet->sname;
                                 i = 0;
-                                length = 64;
+                                length = sizeof(packet->sname);
                                 curr = SNAME_FIELD;
-                        } else done = 1;
+                        } else
+                                return NULL;
                         break;
                 default:
                         i += optionptr[OPT_LEN + i] + 2;
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 5e9adf881..33a968ce9 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -6,7 +6,7 @@
 #define TYPE_MASK       0x0F
 
 enum {
-        OPTION_IP=1,
+        OPTION_IP = 1,
         OPTION_IP_PAIR,
         OPTION_STRING,
 #if ENABLE_FEATURE_RFC3397
diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c
index 41cd32135..0abe851a4 100644
--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -57,7 +57,7 @@ int udhcp_get_packet(struct dhcpMessage *packet, int fd)
                 return -1;
         }
 
-        if (ntohl(packet->cookie) != DHCP_MAGIC) {
+        if (packet->cookie != htonl(DHCP_MAGIC)) {
                 bb_error_msg("received bogus message, ignoring");
                 return -2;
         }
@@ -123,7 +123,6 @@ uint16_t udhcp_checksum(void *addr, int count)
 
 
 /* Construct a ip/udp header for a packet, and specify the source and dest hardware address */
-void BUG_sizeof_struct_udp_dhcp_packet_must_be_576(void);
 int udhcp_raw_packet(struct dhcpMessage *payload,
                 uint32_t source_ip, int source_port,
                 uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, int ifindex)
@@ -169,9 +168,6 @@ int udhcp_raw_packet(struct dhcpMessage *payload,
         packet.ip.ttl = IPDEFTTL;
         packet.ip.check = udhcp_checksum(&(packet.ip), sizeof(packet.ip));
 
-        if (sizeof(struct udp_dhcp_packet) != 576)
-                BUG_sizeof_struct_udp_dhcp_packet_must_be_576();
-
         result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
                         (struct sockaddr *) &dest, sizeof(dest));
         if (result <= 0) {