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

diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c
index e7eeb58..4a5c627 100644 (file)
--- 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 179c21f..4f2d31c 100644 (file)
--- 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 3168fc6..2b4f164 100644 (file)
--- 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 5e9adf8..33a968c 100644 (file)
--- 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 41cd321..0abe851 100644 (file)
--- 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) {