udhcp: MAC_BCAST_ADDR and blank_chaddr are in fact constant, move to rodata.

a few global variables reduced to smallints
function                                             old     new   delta
add_lease                                             75     227    +152
static.blank_chaddr                                    -      16     +16
MAC_BCAST_ADDR                                         -       6      +6
sockfd                                                 4       8      +4
udhcp_run_script                                    1153    1155      +2
state                                                  8       5      -3
listen_mode                                            4       1      -3
perform_release                                      152     148      -4
fd                                                     8       4      -4
blank_chaddr                                          16       -     -16
udhcpc_main                                         2518    2497     -21
.rodata                                           131864  131832     -32
oldest_expired_lease                                  61       -     -61
clear_lease                                          127       -    -127
------------------------------------------------------------------------------
(add/remove: 2/3 grow/shrink: 3/6 up/down: 180/-271)          Total: -91 bytes

9 files changed, 169 insertions, 156 deletions

diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index 46cc0348f..721888f6d 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -15,6 +15,8 @@
 #include "common.h"
 
 
+const uint8_t MAC_BCAST_ADDR[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
 long uptime(void)
 {
         struct sysinfo info;
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index 00890ac1c..6c0db5b4c 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -14,8 +14,7 @@
 
 #define DEFAULT_SCRIPT  "/usr/share/udhcpc/default.script"
 
-#define COMBINED_BINARY
-
+extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */
 
 /*** packet.h ***/
 
@@ -52,7 +51,8 @@ int udhcp_get_packet(struct dhcpMessage *packet, int fd);
 uint16_t udhcp_checksum(void *addr, int count);
 int udhcp_raw_packet(struct dhcpMessage *payload,
                 uint32_t source_ip, int source_port,
-                uint32_t dest_ip, int dest_port, uint8_t *dest_arp, int ifindex);
+                uint32_t dest_ip, int dest_port,
+                const uint8_t *dest_arp, int ifindex);
 int udhcp_kernel_packet(struct dhcpMessage *payload,
                 uint32_t source_ip, int source_port,
                 uint32_t dest_ip, int dest_port);
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index e8cdd79df..362e70169 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -17,22 +17,23 @@
 #include "options.h"
 
 
-static int state;
 /* 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 unsigned long timeout;
 static unsigned long requested_ip; /* = 0 */
 static uint32_t server_addr;
-static unsigned long timeout;
 static int packet_num; /* = 0 */
-static int fd = -1;
+static int sockfd = -1;
 
 #define LISTEN_NONE 0
 #define LISTEN_KERNEL 1
 #define LISTEN_RAW 2
-static int listen_mode;
+static smallint listen_mode;
+
+static smallint state;
 
 struct client_config_t client_config;
 
@@ -42,8 +43,10 @@ static void change_mode(int new_mode)
 {
         DEBUG("entering %s listen mode",
                 new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
-        if (fd >= 0) close(fd);
-        fd = -1;
+        if (sockfd >= 0) {
+                close(sockfd);
+                sockfd = -1;
+        }
         listen_mode = new_mode;
 }
 
@@ -111,6 +114,7 @@ static void client_background(void)
  * If that will be properly disabled for NOMMU, client_background()
  * will work on NOMMU too */
 #else
+// chdir(/) is problematic. Imagine that e.g. pidfile name is RELATIVE! what will unlink do then, eh?
         bb_daemonize(DAEMON_CHDIR_ROOT);
         logmode &= ~LOGMODE_STDIO;
 #endif
@@ -289,13 +293,13 @@ int udhcpc_main(int argc, char **argv)
                 tv.tv_sec = timeout - uptime();
                 tv.tv_usec = 0;
 
-                if (listen_mode != LISTEN_NONE && fd < 0) {
+                if (listen_mode != LISTEN_NONE && sockfd < 0) {
                         if (listen_mode == LISTEN_KERNEL)
-                                fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
+                                sockfd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
                         else
-                                fd = raw_socket(client_config.ifindex);
+                                sockfd = raw_socket(client_config.ifindex);
                 }
-                max_fd = udhcp_sp_fd_set(&rfds, fd);
+                max_fd = udhcp_sp_fd_set(&rfds, sockfd);
 
                 if (tv.tv_sec > 0) {
                         DEBUG("Waiting on select...");
@@ -342,7 +346,8 @@ int udhcpc_main(int argc, char **argv)
                                         packet_num++;
                                 } else {
                                         /* timed out, go back to init state */
-                                        if (state == RENEW_REQUESTED) udhcp_run_script(NULL, "deconfig");
+                                        if (state == RENEW_REQUESTED)
+                                                udhcp_run_script(NULL, "deconfig");
                                         state = INIT_SELECTING;
                                         timeout = now;
                                         packet_num = 0;
@@ -393,12 +398,12 @@ int udhcpc_main(int argc, char **argv)
                                 timeout = 0x7fffffff;
                                 break;
                         }
-                } else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
+                } else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
                         /* a packet is ready, read it */
 
                         if (listen_mode == LISTEN_KERNEL)
-                                len = udhcp_get_packet(&packet, fd);
-                        else len = get_raw_packet(&packet, fd);
+                                len = udhcp_get_packet(&packet, sockfd);
+                        else len = get_raw_packet(&packet, sockfd);
 
                         if (len == -1 && errno != EINTR) {
                                 DEBUG("error on read, %s, reopening socket", strerror(errno));
@@ -418,7 +423,8 @@ int udhcpc_main(int argc, char **argv)
                                 continue;
                         }
 
-                        if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
+                        message = get_option(&packet, DHCP_MESSAGE_TYPE);
+                        if (message == NULL) {
                                 bb_error_msg("cannot get option from packet - ignoring");
                                 continue;
                         }
diff --git a/networking/udhcp/dhcpd.h b/networking/udhcp/dhcpd.h
index 40959e4ae..7c4fe695a 100644
--- a/networking/udhcp/dhcpd.h
+++ b/networking/udhcp/dhcpd.h
@@ -14,81 +14,6 @@
 /* where to find the DHCP server configuration file */
 #define DHCPD_CONF_FILE         "/etc/udhcpd.conf"
 
-/*****************************************************************/
-/* Do not modify below here unless you know what you are doing!! */
-/*****************************************************************/
-
-/* DHCP protocol -- see RFC 2131 */
-#define SERVER_PORT             67
-#define CLIENT_PORT             68
-
-#define DHCP_MAGIC              0x63825363
-
-/* DHCP option codes (partial list) */
-#define DHCP_PADDING            0x00
-#define DHCP_SUBNET             0x01
-#define DHCP_TIME_OFFSET        0x02
-#define DHCP_ROUTER             0x03
-#define DHCP_TIME_SERVER        0x04
-#define DHCP_NAME_SERVER        0x05
-#define DHCP_DNS_SERVER         0x06
-#define DHCP_LOG_SERVER         0x07
-#define DHCP_COOKIE_SERVER      0x08
-#define DHCP_LPR_SERVER         0x09
-#define DHCP_HOST_NAME          0x0c
-#define DHCP_BOOT_SIZE          0x0d
-#define DHCP_DOMAIN_NAME        0x0f
-#define DHCP_SWAP_SERVER        0x10
-#define DHCP_ROOT_PATH          0x11
-#define DHCP_IP_TTL             0x17
-#define DHCP_MTU                0x1a
-#define DHCP_BROADCAST          0x1c
-#define DHCP_NTP_SERVER         0x2a
-#define DHCP_WINS_SERVER        0x2c
-#define DHCP_REQUESTED_IP       0x32
-#define DHCP_LEASE_TIME         0x33
-#define DHCP_OPTION_OVER        0x34
-#define DHCP_MESSAGE_TYPE       0x35
-#define DHCP_SERVER_ID          0x36
-#define DHCP_PARAM_REQ          0x37
-#define DHCP_MESSAGE            0x38
-#define DHCP_MAX_SIZE           0x39
-#define DHCP_T1                 0x3a
-#define DHCP_T2                 0x3b
-#define DHCP_VENDOR             0x3c
-#define DHCP_CLIENT_ID          0x3d
-#define DHCP_FQDN               0x51
-
-#define DHCP_END                0xFF
-
-
-#define BOOTREQUEST             1
-#define BOOTREPLY               2
-
-#define ETH_10MB                1
-#define ETH_10MB_LEN            6
-
-#define DHCPDISCOVER            1
-#define DHCPOFFER               2
-#define DHCPREQUEST             3
-#define DHCPDECLINE             4
-#define DHCPACK                 5
-#define DHCPNAK                 6
-#define DHCPRELEASE             7
-#define DHCPINFORM              8
-
-#define BROADCAST_FLAG          0x8000
-
-#define OPTION_FIELD            0
-#define FILE_FIELD              1
-#define SNAME_FIELD             2
-
-/* miscellaneous defines */
-#define MAC_BCAST_ADDR          (uint8_t *) "\xff\xff\xff\xff\xff\xff"
-#define OPT_CODE 0
-#define OPT_LEN 1
-#define OPT_DATA 2
-
 struct option_set {
         uint8_t *data;
         struct option_set *next;
@@ -140,13 +65,9 @@ struct dhcpOfferedAddr {
         uint32_t expires;       /* host order */
 };
 
-extern uint8_t blank_chaddr[];
-
-void clear_lease(uint8_t *chaddr, uint32_t yiaddr);
-struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease);
+struct dhcpOfferedAddr *add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease);
 int lease_expired(struct dhcpOfferedAddr *lease);
-struct dhcpOfferedAddr *oldest_expired_lease(void);
-struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr);
+struct dhcpOfferedAddr *find_lease_by_chaddr(const uint8_t *chaddr);
 struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr);
 uint32_t find_address(int check_expired);
 
diff --git a/networking/udhcp/leases.c b/networking/udhcp/leases.c
index 2f7847d74..5d8775f63 100644
--- a/networking/udhcp/leases.c
+++ b/networking/udhcp/leases.c
@@ -8,25 +8,41 @@
 #include "dhcpd.h"
 
 
-uint8_t blank_chaddr[] = {[0 ... 15] = 0};
+/* Find the oldest expired lease, NULL if there are no expired leases */
+static struct dhcpOfferedAddr *oldest_expired_lease(void)
+{
+        struct dhcpOfferedAddr *oldest = NULL;
+        unsigned long oldest_lease = time(0);
+        unsigned i;
+
+
+        for (i = 0; i < server_config.max_leases; i++)
+                if (oldest_lease > leases[i].expires) {
+                        oldest_lease = leases[i].expires;
+                        oldest = &(leases[i]);
+                }
+        return oldest;
+}
+
 
 /* clear every lease out that chaddr OR yiaddr matches and is nonzero */
-void clear_lease(uint8_t *chaddr, uint32_t yiaddr)
+static void clear_lease(const uint8_t *chaddr, uint32_t yiaddr)
 {
-        unsigned int i, j;
+        unsigned i, j;
 
         for (j = 0; j < 16 && !chaddr[j]; j++);
 
         for (i = 0; i < server_config.max_leases; i++)
-                if ((j != 16 && !memcmp(leases[i].chaddr, chaddr, 16)) ||
-                    (yiaddr && leases[i].yiaddr == yiaddr)) {
+                if ((j != 16 && memcmp(leases[i].chaddr, chaddr, 16) != 0)
+                 || (yiaddr && leases[i].yiaddr == yiaddr)
+                ) {
                         memset(&(leases[i]), 0, sizeof(struct dhcpOfferedAddr));
                 }
 }
 
 
 /* add a lease into the table, clearing out any old ones */
-struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
+struct dhcpOfferedAddr *add_lease(const uint8_t *chaddr, uint32_t yiaddr, unsigned long lease)
 {
         struct dhcpOfferedAddr *oldest;
 
@@ -52,31 +68,14 @@ int lease_expired(struct dhcpOfferedAddr *lease)
 }
 
 
-/* Find the oldest expired lease, NULL if there are no expired leases */
-struct dhcpOfferedAddr *oldest_expired_lease(void)
-{
-        struct dhcpOfferedAddr *oldest = NULL;
-        unsigned long oldest_lease = time(0);
-        unsigned int i;
-
-
-        for (i = 0; i < server_config.max_leases; i++)
-                if (oldest_lease > leases[i].expires) {
-                        oldest_lease = leases[i].expires;
-                        oldest = &(leases[i]);
-                }
-        return oldest;
-
-}
-
-
 /* Find the first lease that matches chaddr, NULL if no match */
-struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr)
+struct dhcpOfferedAddr *find_lease_by_chaddr(const uint8_t *chaddr)
 {
-        unsigned int i;
+        unsigned i;
 
         for (i = 0; i < server_config.max_leases; i++)
-                if (!memcmp(leases[i].chaddr, chaddr, 16)) return &(leases[i]);
+                if (!memcmp(leases[i].chaddr, chaddr, 16))
+                        return &(leases[i]);
 
         return NULL;
 }
@@ -85,10 +84,11 @@ struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr)
 /* Find the first lease that matches yiaddr, NULL is no match */
 struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr)
 {
-        unsigned int i;
+        unsigned i;
 
         for (i = 0; i < server_config.max_leases; i++)
-                if (leases[i].yiaddr == yiaddr) return &(leases[i]);
+                if (leases[i].yiaddr == yiaddr)
+                        return &(leases[i]);
 
         return NULL;
 }
@@ -97,6 +97,8 @@ 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 check_ip(uint32_t addr)
 {
+        static const uint8_t blank_chaddr[16]; /* 16 zero bytes */
+
         struct in_addr temp;
 
         if (arpping(addr, server_config.server, server_config.arp, server_config.interface) == 0) {
@@ -105,7 +107,8 @@ static int check_ip(uint32_t addr)
                         inet_ntoa(temp), server_config.conflict_time);
                 add_lease(blank_chaddr, addr, server_config.conflict_time);
                 return 1;
-        } else return 0;
+        }
+        return 0;
 }
 
 
@@ -125,7 +128,7 @@ uint32_t find_address(int check_expired)
                 /* ie, 192.168.55.255 */
                 if ((addr & 0xFF) == 0xFF) continue;
 
-                /* Only do if it isn't an assigned as a static lease */
+                /* Only do if it isn't assigned as a static lease */
                 if (!reservedIp(server_config.static_leases, htonl(addr))) {
 
                         /* lease is not taken */
@@ -133,11 +136,10 @@ uint32_t find_address(int check_expired)
                         lease = find_lease_by_yiaddr(ret);
 
                         /* no lease or it expired and we are checking for expired leases */
-                        if ( (!lease || (check_expired && lease_expired(lease)))
+                        if ((!lease || (check_expired && lease_expired(lease)))
                          && /* and it isn't on the network */ !check_ip(ret)
                         ) {
                                 return ret;
-                                break;
                         }
                 }
         }
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 11f013fd4..5e9adf881 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -23,6 +23,80 @@ enum {
 #define OPTION_REQ      0x10 /* have the client request this option */
 #define OPTION_LIST     0x20 /* There can be a list of 1 or more of these */
 
+/*****************************************************************/
+/* Do not modify below here unless you know what you are doing!! */
+/*****************************************************************/
+
+/* DHCP protocol -- see RFC 2131 */
+#define SERVER_PORT             67
+#define CLIENT_PORT             68
+
+#define DHCP_MAGIC              0x63825363
+
+/* DHCP option codes (partial list) */
+#define DHCP_PADDING            0x00
+#define DHCP_SUBNET             0x01
+#define DHCP_TIME_OFFSET        0x02
+#define DHCP_ROUTER             0x03
+#define DHCP_TIME_SERVER        0x04
+#define DHCP_NAME_SERVER        0x05
+#define DHCP_DNS_SERVER         0x06
+#define DHCP_LOG_SERVER         0x07
+#define DHCP_COOKIE_SERVER      0x08
+#define DHCP_LPR_SERVER         0x09
+#define DHCP_HOST_NAME          0x0c
+#define DHCP_BOOT_SIZE          0x0d
+#define DHCP_DOMAIN_NAME        0x0f
+#define DHCP_SWAP_SERVER        0x10
+#define DHCP_ROOT_PATH          0x11
+#define DHCP_IP_TTL             0x17
+#define DHCP_MTU                0x1a
+#define DHCP_BROADCAST          0x1c
+#define DHCP_NTP_SERVER         0x2a
+#define DHCP_WINS_SERVER        0x2c
+#define DHCP_REQUESTED_IP       0x32
+#define DHCP_LEASE_TIME         0x33
+#define DHCP_OPTION_OVER        0x34
+#define DHCP_MESSAGE_TYPE       0x35
+#define DHCP_SERVER_ID          0x36
+#define DHCP_PARAM_REQ          0x37
+#define DHCP_MESSAGE            0x38
+#define DHCP_MAX_SIZE           0x39
+#define DHCP_T1                 0x3a
+#define DHCP_T2                 0x3b
+#define DHCP_VENDOR             0x3c
+#define DHCP_CLIENT_ID          0x3d
+#define DHCP_FQDN               0x51
+
+#define DHCP_END                0xFF
+
+
+#define BOOTREQUEST             1
+#define BOOTREPLY               2
+
+#define ETH_10MB                1
+#define ETH_10MB_LEN            6
+
+#define DHCPDISCOVER            1
+#define DHCPOFFER               2
+#define DHCPREQUEST             3
+#define DHCPDECLINE             4
+#define DHCPACK                 5
+#define DHCPNAK                 6
+#define DHCPRELEASE             7
+#define DHCPINFORM              8
+
+#define BROADCAST_FLAG          0x8000
+
+#define OPTION_FIELD            0
+#define FILE_FIELD              1
+#define SNAME_FIELD             2
+
+/* miscellaneous defines */
+#define OPT_CODE 0
+#define OPT_LEN 1
+#define OPT_DATA 2
+
 struct dhcp_option {
         char name[12];
         char flags;
diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c
index 25c55faab..da3807773 100644
--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -112,7 +112,7 @@ uint16_t udhcp_checksum(void *addr, int count)
 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, uint8_t *dest_arp, int ifindex)
+                uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, int ifindex)
 {
         int fd;
         int result;
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index dc8ff7a1c..98706a592 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -9,7 +9,6 @@
  */
 
 #include "common.h"
-#include "dhcpd.h"
 #include "dhcpc.h"
 #include "options.h"
 
@@ -77,7 +76,7 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p)
                 switch (type) {
                 case OPTION_IP_PAIR:
                         dest += sprintip(dest, "", option);
-                        *(dest++) = '/';
+                        *dest++ = '/';
                         option += 4;
                         optlen = 4;
                 case OPTION_IP: /* Works regardless of host byte order. */
@@ -132,34 +131,42 @@ static char **fill_envp(struct dhcpMessage *packet)
         int num_options = 0;
         int i, j;
         char **envp;
+        char *var;
         uint8_t *temp;
         struct in_addr subnet;
         char over = 0;
 
-        if (packet == NULL)
-                num_options = 0;
-        else {
-                for (i = 0; dhcp_options[i].code; i++)
+        if (packet) {
+                for (i = 0; dhcp_options[i].code; i++) {
                         if (get_option(packet, dhcp_options[i].code)) {
                                 num_options++;
                                 if (dhcp_options[i].code == DHCP_SUBNET)
                                         num_options++; /* for mton */
                         }
-                if (packet->siaddr) num_options++;
-                if ((temp = get_option(packet, DHCP_OPTION_OVER)))
+                }
+                if (packet->siaddr)
+                        num_options++;
+                temp = get_option(packet, DHCP_OPTION_OVER);
+                if (temp)
                         over = *temp;
-                if (!(over & FILE_FIELD) && packet->file[0]) num_options++;
-                if (!(over & SNAME_FIELD) && packet->sname[0]) num_options++;
+                if (!(over & FILE_FIELD) && packet->file[0])
+                        num_options++;
+                if (!(over & SNAME_FIELD) && packet->sname[0])
+                        num_options++;
         }
 
         envp = xzalloc(sizeof(char *) * (num_options + 5));
         j = 0;
         envp[j++] = xasprintf("interface=%s", client_config.interface);
-        envp[j++] = xasprintf("PATH=%s",
-                getenv("PATH") ? : "/bin:/usr/bin:/sbin:/usr/sbin");
-        envp[j++] = xasprintf("HOME=%s", getenv("HOME") ? : "/");
+        var = getenv("PATH");
+        if (var)
+                envp[j++] = xasprintf("PATH=%s", var);
+        var = getenv("HOME");
+        if (var)
+                envp[j++] = xasprintf("HOME=%s", var);
 
-        if (packet == NULL) return envp;
+        if (packet == NULL)
+                return envp;
 
         envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
         sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
@@ -206,19 +213,20 @@ void udhcp_run_script(struct dhcpMessage *packet, const char *name)
         DEBUG("vfork'ing and execle'ing %s", client_config.script);
 
         envp = fill_envp(packet);
+
         /* call script */
+// can we use wait4pid(spawn(...)) here?
         pid = vfork();
-        if (pid) {
-                waitpid(pid, NULL, 0);
-                for (curr = envp; *curr; curr++) free(*curr);
-                free(envp);
-                return;
-        } else if (pid == 0) {
+        if (pid < 0) return;
+        if (pid == 0) {
                 /* close fd's? */
                 /* exec script */
                 execle(client_config.script, client_config.script,
                        name, NULL, envp);
-                bb_perror_msg("script %s failed", client_config.script);
-                exit(1);
+                bb_perror_msg_and_die("script %s failed", client_config.script);
         }
+        waitpid(pid, NULL, 0);
+        for (curr = envp; *curr; curr++)
+                free(*curr);
+        free(envp);
 }
diff --git a/networking/udhcp/serverpacket.c b/networking/udhcp/serverpacket.c
index 8889fda86..e1a88addd 100644
--- a/networking/udhcp/serverpacket.c
+++ b/networking/udhcp/serverpacket.c
@@ -38,7 +38,7 @@ static int send_packet_to_relay(struct dhcpMessage *payload)
 /* send a packet to a specific arp address and ip address by creating our own ip packet */
 static int send_packet_to_client(struct dhcpMessage *payload, int force_broadcast)
 {
-        uint8_t *chaddr;
+        const uint8_t *chaddr;
         uint32_t ciaddr;
 
         if (force_broadcast) {