[DHCPD] add new version DHCPD use lwip raw api.

components/net/lwip_dhcpd/SConscript

@@ -1,7 +1,11 @@
 from building import *
 
 cwd = GetCurrentDir()
-src = Glob('*.c')
+
+if GetDepend('RT_USING_LWIP202'):
+    src = ['dhcp_server_raw.c']
+else:
+    src = ['dhcp_server.c']
 
 CPPPATH = [cwd]
 

components/net/lwip_dhcpd/dhcp_server.h

@@ -31,7 +31,15 @@
 #ifndef DHCPV4_SERVER_H__
 #define DHCPV4_SERVER_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void dhcpd_start(const char *netif_name);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
 

components/net/lwip_dhcpd/dhcp_server_raw.c

@@ -0,0 +1,742 @@
+/*
+ * File      : dhcp_server_raw.c
+ *             A simple DHCP server implementation
+ *
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2011-2018, Shanghai Real-Thread Technology Co., Ltd
+ * http://www.rt-thread.com
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2014-04-01     Ren.Haibo    the first version
+ * 2018-06-12     aozima       ignore DHCP_OPTION_SERVER_ID.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include <rtthread.h>
+
+#include <lwip/opt.h>
+#include <lwip/sockets.h>
+#include <lwip/inet_chksum.h>
+#include <netif/etharp.h>
+#include <netif/ethernetif.h>
+#include <lwip/ip.h>
+#include <lwip/init.h>
+
+#if (LWIP_VERSION) < 0x02000000U
+    #error "not support old LWIP"
+#endif
+
+#if !LWIP_IPV4
+    #error "must enable IPV4"
+#endif
+
+#if (LWIP_VERSION) >= 0x02000000U
+    #include <lwip/prot/dhcp.h>
+#endif
+
+/* DHCP server option */
+
+/* allocated client ip range */
+#ifndef DHCPD_CLIENT_IP_MIN
+    #define DHCPD_CLIENT_IP_MIN     2
+#endif
+#ifndef DHCPD_CLIENT_IP_MAX
+    #define DHCPD_CLIENT_IP_MAX     254
+#endif
+
+/* the DHCP server address */
+#ifndef DHCPD_SERVER_IP
+    #define DHCPD_SERVER_IP "192.168.169.1"
+#endif
+
+#define DHCP_DEBUG_PRINTF
+
+#ifdef  DHCP_DEBUG_PRINTF
+    #define DEBUG_PRINTF        rt_kprintf("[DHCP] "); rt_kprintf
+#else
+    #define DEBUG_PRINTF(...)
+#endif /* DHCP_DEBUG_PRINTF */
+
+/* we need some routines in the DHCP of lwIP */
+#undef  LWIP_DHCP
+#define LWIP_DHCP   1
+#include <lwip/dhcp.h>
+
+/** Mac address length  */
+#define DHCP_MAX_HLEN               6
+/** dhcp default live time */
+#define DHCP_DEFAULT_LIVE_TIME      0x80510100
+
+/** Minimum length for request before packet is parsed */
+#define DHCP_MIN_REQUEST_LEN        44
+
+#define LWIP_NETIF_LOCK(...)
+#define LWIP_NETIF_UNLOCK(...)
+
+/**
+* The dhcp client node struct.
+*/
+struct dhcp_client_node
+{
+    struct dhcp_client_node *next;
+    u8_t chaddr[DHCP_MAX_HLEN];
+    ip4_addr_t ipaddr;
+    u32_t lease_end;
+};
+
+/**
+* The dhcp server struct.
+*/
+struct dhcp_server
+{
+    struct dhcp_server *next;
+    struct netif *netif;
+    struct udp_pcb *pcb;
+    struct dhcp_client_node *node_list;
+    ip4_addr_t start;
+    ip4_addr_t end;
+    ip4_addr_t current;
+};
+
+static u8_t *dhcp_server_option_find(u8_t *buf, u16_t len, u8_t option);
+
+/**
+* The dhcp server struct list.
+*/
+static struct dhcp_server *lw_dhcp_server;
+
+/**
+* Find a dhcp client node by mac address
+*
+* @param dhcpserver The dhcp server
+* @param chaddr Mac address
+* @param hlen   Mac address length
+* @return dhcp client node
+*/
+static struct dhcp_client_node *
+dhcp_client_find_by_mac(struct dhcp_server *dhcpserver, const u8_t *chaddr, u8_t hlen)
+{
+    struct dhcp_client_node *node;
+
+    for (node = dhcpserver->node_list; node != NULL; node = node->next)
+    {
+        if (memcmp(node->chaddr, chaddr, hlen) == 0)
+        {
+            return node;
+        }
+    }
+
+    return NULL;
+}
+
+/**
+* Find a dhcp client node by ip address
+*
+* @param dhcpserver The dhcp server
+* @param chaddr Mac address
+* @param hlen   Mac address length
+* @return dhcp client node
+*/
+static struct dhcp_client_node *
+dhcp_client_find_by_ip(struct dhcp_server *dhcpserver, const ip4_addr_t *ip)
+{
+    struct dhcp_client_node *node;
+
+    for (node = dhcpserver->node_list; node != NULL; node = node->next)
+    {
+        if (ip4_addr_cmp(&node->ipaddr, ip))
+        {
+            return node;
+        }
+    }
+
+    return NULL;
+}
+
+/**
+* Find a dhcp client node by ip address
+*
+* @param dhcpserver The dhcp server
+* @param chaddr Mac address
+* @param hlen   Mac address length
+* @return dhcp client node
+*/
+static struct dhcp_client_node *
+dhcp_client_find(struct dhcp_server *dhcpserver, struct dhcp_msg *msg,
+                 u8_t *opt_buf, u16_t len)
+{
+    u8_t *opt;
+    //u32_t ipaddr;
+    struct dhcp_client_node *node;
+
+    node = dhcp_client_find_by_mac(dhcpserver, msg->chaddr, msg->hlen);
+    if (node != NULL)
+    {
+        return node;
+    }
+
+    opt = dhcp_server_option_find(opt_buf, len, DHCP_OPTION_REQUESTED_IP);
+    if (opt != NULL)
+    {
+        node = dhcp_client_find_by_ip(dhcpserver, (ip4_addr_t *)(&opt[2]));
+        if (node != NULL)
+        {
+            return node;
+        }
+    }
+
+    return NULL;
+}
+
+/**
+* Find a dhcp client node by ip address
+*
+* @param dhcpserver The dhcp server
+* @param chaddr Mac address
+* @param hlen   Mac address length
+* @return dhcp client node
+*/
+static struct dhcp_client_node *
+dhcp_client_alloc(struct dhcp_server *dhcpserver, struct dhcp_msg *msg,
+                  u8_t *opt_buf, u16_t len)
+{
+    u8_t *opt;
+    u32_t ipaddr;
+    struct dhcp_client_node *node;
+
+    node = dhcp_client_find_by_mac(dhcpserver, msg->chaddr, msg->hlen);
+    if (node != NULL)
+    {
+        return node;
+    }
+
+    opt = dhcp_server_option_find(opt_buf, len, DHCP_OPTION_REQUESTED_IP);
+    if (opt != NULL)
+    {
+        node = dhcp_client_find_by_ip(dhcpserver, (ip4_addr_t *)(&opt[2]));
+        if (node != NULL)
+        {
+            return node;
+        }
+    }
+
+dhcp_alloc_again:
+    node = dhcp_client_find_by_ip(dhcpserver, &dhcpserver->current);
+    if (node != NULL)
+    {
+        ipaddr = (ntohl(dhcpserver->current.addr) + 1);
+        if (ipaddr > ntohl(dhcpserver->end.addr))
+        {
+            ipaddr = ntohl(dhcpserver->start.addr);
+        }
+        dhcpserver->current.addr = htonl(ipaddr);
+        goto dhcp_alloc_again;
+    }
+    node = (struct dhcp_client_node *)mem_malloc(sizeof(struct dhcp_client_node));
+    if (node == NULL)
+    {
+        return NULL;
+    }
+    SMEMCPY(node->chaddr, msg->chaddr, msg->hlen);
+    node->ipaddr = dhcpserver->current;
+
+    node->next = dhcpserver->node_list;
+    dhcpserver->node_list = node;
+
+    return node;
+}
+
+/**
+* find option from buffer.
+*
+* @param buf The buffer to find option
+* @param len The buffer length
+* @param option Which option to find
+* @return dhcp option buffer
+*/
+static u8_t *
+dhcp_server_option_find(u8_t *buf, u16_t len, u8_t option)
+{
+    u8_t *end = buf + len;
+    while ((buf < end) && (*buf != DHCP_OPTION_END))
+    {
+        if (*buf == option)
+        {
+            return buf;
+        }
+        buf += (buf[1] + 2);
+    }
+    return NULL;
+}
+
+/**
+* If an incoming DHCP message is in response to us, then trigger the state machine
+*/
+static void
+dhcp_server_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *recv_addr, u16_t port)
+{
+    struct dhcp_server *dhcp_server = (struct dhcp_server *)arg;
+    struct dhcp_msg *msg;
+    struct pbuf *q;
+    u8_t *opt_buf;
+    u8_t *opt;
+    struct dhcp_client_node *node;
+    u8_t msg_type;
+    u16_t length;
+    ip_addr_t addr = *recv_addr;
+    u32_t tmp;
+
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("[%s:%d] %c%c recv %d\n", __FUNCTION__, __LINE__, dhcp_server->netif->name[0], dhcp_server->netif->name[1], p->tot_len));
+    /* prevent warnings about unused arguments */
+    LWIP_UNUSED_ARG(pcb);
+    LWIP_UNUSED_ARG(addr);
+    LWIP_UNUSED_ARG(port);
+
+    if (p->len < DHCP_MIN_REQUEST_LEN)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP request message or pbuf too short\n"));
+        pbuf_free(p);
+        return;
+    }
+
+    q = pbuf_alloc(PBUF_TRANSPORT, 1500, PBUF_RAM);
+    if (q == NULL)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloc dhcp_msg failed!\n"));
+        pbuf_free(p);
+        return;
+    }
+    if (q->tot_len < p->tot_len)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloc dhcp_msg too small %d:%d\n", q->tot_len, p->tot_len));
+        pbuf_free(p);
+        return;
+    }
+
+    pbuf_copy(q, p);
+    pbuf_free(p);
+
+    msg = (struct dhcp_msg *)q->payload;
+    if (msg->op != DHCP_BOOTREQUEST)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("not a DHCP request message, but type %"U16_F"\n", (u16_t)msg->op));
+        goto free_pbuf_and_return;
+    }
+
+    if (msg->cookie != PP_HTONL(DHCP_MAGIC_COOKIE))
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("bad DHCP_MAGIC_COOKIE!\n"));
+        goto free_pbuf_and_return;
+    }
+
+    if (msg->hlen > DHCP_MAX_HLEN)
+    {
+        goto free_pbuf_and_return;
+    }
+
+    opt_buf = (u8_t *)msg + DHCP_OPTIONS_OFS;
+    length = q->tot_len - DHCP_OPTIONS_OFS;
+    opt = dhcp_server_option_find(opt_buf, length, DHCP_OPTION_MESSAGE_TYPE);
+    if (opt)
+    {
+        msg_type = *(opt + 2);
+        if (msg_type == DHCP_DISCOVER)
+        {
+            node = dhcp_client_alloc(dhcp_server, msg, opt_buf, length);
+            if (node == NULL)
+            {
+                goto free_pbuf_and_return;
+            }
+            node->lease_end = DHCP_DEFAULT_LIVE_TIME;
+            /* create dhcp offer and send */
+            msg->op = DHCP_BOOTREPLY;
+            msg->hops = 0;
+            msg->secs = 0;
+            SMEMCPY(&msg->siaddr, &(dhcp_server->netif->ip_addr), 4);
+            msg->sname[0] = '\0';
+            msg->file[0] = '\0';
+            msg->cookie = PP_HTONL(DHCP_MAGIC_COOKIE);
+            SMEMCPY(&msg->yiaddr, &node->ipaddr, 4);
+
+            opt_buf = (u8_t *)msg + DHCP_OPTIONS_OFS;
+            /* add msg type */
+            *opt_buf++ = DHCP_OPTION_MESSAGE_TYPE;
+            *opt_buf++ = 1;
+            *opt_buf++ = DHCP_OFFER;
+
+            /* add server id */
+            *opt_buf++ = DHCP_OPTION_SERVER_ID;
+            *opt_buf++ = 4;
+            SMEMCPY(opt_buf, &(dhcp_server->netif->ip_addr), 4);
+            opt_buf += 4;
+
+            /* add_lease_time */
+            *opt_buf++ = DHCP_OPTION_LEASE_TIME;
+            *opt_buf++ = 4;
+            tmp = PP_HTONL(DHCP_DEFAULT_LIVE_TIME);
+            SMEMCPY(opt_buf, &tmp, 4);
+            opt_buf += 4;
+
+            /* add config */
+            *opt_buf++ = DHCP_OPTION_SUBNET_MASK;
+            *opt_buf++ = 4;
+            SMEMCPY(opt_buf, &ip_2_ip4(&dhcp_server->netif->netmask)->addr, 4);
+            opt_buf += 4;
+
+            *opt_buf++ = DHCP_OPTION_DNS_SERVER;
+            *opt_buf++ = 4;
+#ifdef DHCP_DNS_SERVER_IP
+            {
+                ip_addr_t dns_addr;
+                ipaddr_aton(DHCP_DNS_SERVER_IP, &dns_addr);
+                SMEMCPY(opt_buf, &ip_2_ip4(&dns_addr)->addr, 4);
+            }
+#else
+            /* default use gatewary dns server */
+            SMEMCPY(opt_buf, &(dhcp_server->netif->ip_addr), 4);
+#endif /* DHCP_DNS_SERVER_IP */
+            opt_buf += 4;
+
+            *opt_buf++ = DHCP_OPTION_ROUTER;
+            *opt_buf++ = 4;
+            SMEMCPY(opt_buf, &ip_2_ip4(&dhcp_server->netif->ip_addr)->addr, 4);
+            opt_buf += 4;
+
+            /* add option end */
+            *opt_buf++ = DHCP_OPTION_END;
+
+            length = (u32_t)opt_buf - (u32_t)msg;
+            if (length < q->tot_len)
+            {
+                pbuf_realloc(q, length);
+            }
+
+            ip_2_ip4(&addr)->addr = INADDR_BROADCAST;
+            udp_sendto_if(pcb, q, &addr, port, dhcp_server->netif);
+        }
+        else
+        {
+            if (1)
+            {
+                if (msg_type == DHCP_REQUEST)
+                {
+                    node = dhcp_client_find(dhcp_server, msg, opt_buf, length);
+                    if (node != NULL)
+                    {
+                        /* Send ack */
+                        node->lease_end = DHCP_DEFAULT_LIVE_TIME;
+                        /* create dhcp offer and send */
+                        msg->op = DHCP_BOOTREPLY;
+                        msg->hops = 0;
+                        msg->secs = 0;
+                        SMEMCPY(&msg->siaddr, &(dhcp_server->netif->ip_addr), 4);
+                        msg->sname[0] = '\0';
+                        msg->file[0] = '\0';
+                        msg->cookie = PP_HTONL(DHCP_MAGIC_COOKIE);
+                        SMEMCPY(&msg->yiaddr, &node->ipaddr, 4);
+                        opt_buf = (u8_t *)msg + DHCP_OPTIONS_OFS;
+
+                        /* add msg type */
+                        *opt_buf++ = DHCP_OPTION_MESSAGE_TYPE;
+                        *opt_buf++ = 1;
+                        *opt_buf++ = DHCP_ACK;
+
+                        /* add server id */
+                        *opt_buf++ = DHCP_OPTION_SERVER_ID;
+                        *opt_buf++ = 4;
+                        SMEMCPY(opt_buf, &(dhcp_server->netif->ip_addr), 4);
+                        opt_buf += 4;
+
+                        /* add_lease_time */
+                        *opt_buf++ = DHCP_OPTION_LEASE_TIME;
+                        *opt_buf++ = 4;
+                        tmp = PP_HTONL(DHCP_DEFAULT_LIVE_TIME);
+                        SMEMCPY(opt_buf, &tmp, 4);
+                        opt_buf += 4;
+
+                        /* add config */
+                        *opt_buf++ = DHCP_OPTION_SUBNET_MASK;
+                        *opt_buf++ = 4;
+                        SMEMCPY(opt_buf, &ip_2_ip4(&dhcp_server->netif->netmask)->addr, 4);
+                        opt_buf += 4;
+
+                        *opt_buf++ = DHCP_OPTION_DNS_SERVER;
+                        *opt_buf++ = 4;
+#ifdef DHCP_DNS_SERVER_IP
+                        {
+                            ip_addr_t dns_addr;
+                            ipaddr_aton(DHCP_DNS_SERVER_IP, &dns_addr);
+                            SMEMCPY(opt_buf, &ip_2_ip4(&dns_addr)->addr, 4);
+                        }
+#else
+                        /* default use gatewary dns server */
+                        SMEMCPY(opt_buf, &(dhcp_server->netif->ip_addr), 4);
+#endif /* DHCP_DNS_SERVER_IP */
+                        opt_buf += 4;
+
+                        *opt_buf++ = DHCP_OPTION_ROUTER;
+                        *opt_buf++ = 4;
+                        SMEMCPY(opt_buf, &ip_2_ip4(&dhcp_server->netif->ip_addr)->addr, 4);
+                        opt_buf += 4;
+
+                        /* add option end */
+                        *opt_buf++ = DHCP_OPTION_END;
+
+                        length = (u32_t)opt_buf - (u32_t)msg;
+                        if (length < q->tot_len)
+                        {
+                            pbuf_realloc(q, length);
+                        }
+
+                        ip_2_ip4(&addr)->addr = INADDR_BROADCAST;
+                        udp_sendto_if(pcb, q, &addr, port, dhcp_server->netif);
+                    }
+                    else
+                    {
+                        /* Send no ack */
+                        /* create dhcp offer and send */
+                        msg->op = DHCP_BOOTREPLY;
+                        msg->hops = 0;
+                        msg->secs = 0;
+                        SMEMCPY(&msg->siaddr, &(dhcp_server->netif->ip_addr), 4);
+                        msg->sname[0] = '\0';
+                        msg->file[0] = '\0';
+                        msg->cookie = PP_HTONL(DHCP_MAGIC_COOKIE);
+                        memset(&msg->yiaddr, 0, 4);
+                        opt_buf = (u8_t *)msg + DHCP_OPTIONS_OFS;
+
+                        /* add msg type */
+                        *opt_buf++ = DHCP_OPTION_MESSAGE_TYPE;
+                        *opt_buf++ = 1;
+                        *opt_buf++ = DHCP_NAK;
+
+                        /* add server id */
+                        *opt_buf++ = DHCP_OPTION_SERVER_ID;
+                        *opt_buf++ = 4;
+                        SMEMCPY(opt_buf, &(dhcp_server->netif->ip_addr), 4);
+                        opt_buf += 4;
+
+                        /* add option end */
+                        *opt_buf++ = DHCP_OPTION_END;
+                        length = (u32_t)opt_buf - (u32_t)msg;
+                        if (length < q->tot_len)
+                        {
+                            pbuf_realloc(q, length);
+                        }
+
+                        ip_2_ip4(&addr)->addr = INADDR_BROADCAST;
+                        udp_sendto_if(pcb, q, &addr, port, dhcp_server->netif);
+                    }
+                }
+                else if (msg_type == DHCP_RELEASE)
+                {
+                    struct dhcp_client_node *node_prev = NULL;
+
+                    for (node = dhcp_server->node_list; node != NULL; node = node->next)
+                    {
+                        if (memcmp(node->chaddr, msg->chaddr, msg->hlen) == 0)
+                        {
+                            if (node == dhcp_server->node_list)
+                            {
+                                dhcp_server->node_list = node->next;
+                            }
+                            else
+                            {
+                                node_prev->next = node->next;
+                            }
+                            break;
+                        }
+                        node_prev = node;
+                        node = node->next;
+                    }
+
+                    if (node != NULL)
+                    {
+                        mem_free(node);
+                    }
+                }
+                else if (msg_type ==  DHCP_DECLINE)
+                {
+                    ;
+                }
+                else if (msg_type == DHCP_INFORM)
+                {
+                    ;
+                }
+            }
+        }
+    }
+
+free_pbuf_and_return:
+    pbuf_free(q);
+}
+
+/**
+* start dhcp server for a netif
+*
+* @param netif The netif which use dhcp server
+* @param start The Start IP address
+* @param end The netif which use dhcp server
+* @return lwIP error code
+* - ERR_OK - No error
+* - ERR_MEM - Out of memory
+*/
+err_t
+dhcp_server_start(struct netif *netif, ip4_addr_t *start, ip4_addr_t *end)
+{
+    struct dhcp_server *dhcp_server;
+
+    /* If this netif alreday use the dhcp server. */
+    for (dhcp_server = lw_dhcp_server; dhcp_server != NULL; dhcp_server = dhcp_server->next)
+    {
+        if (dhcp_server->netif == netif)
+        {
+            dhcp_server->start = *start;
+            dhcp_server->end = *end;
+            dhcp_server->current = *start;
+            return ERR_OK;
+        }
+    }
+
+    dhcp_server = NULL;
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_server_start(): starting new DHCP server\n"));
+    dhcp_server = (struct dhcp_server *)mem_malloc(sizeof(struct dhcp_server));
+    if (dhcp_server == NULL)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_server_start(): could not allocate dhcp\n"));
+        return ERR_MEM;
+    }
+
+    /* clear data structure */
+    memset(dhcp_server, 0, sizeof(struct dhcp_server));
+
+    /* store this dhcp server to list */
+    dhcp_server->next = lw_dhcp_server;
+    lw_dhcp_server = dhcp_server;
+    dhcp_server->netif = netif;
+    dhcp_server->node_list = NULL;
+    dhcp_server->start = *start;
+    dhcp_server->end = *end;
+    dhcp_server->current = *start;
+
+    /* allocate UDP PCB */
+    dhcp_server->pcb = udp_new();
+    if (dhcp_server->pcb == NULL)
+    {
+        LWIP_DEBUGF(DHCP_DEBUG  | LWIP_DBG_TRACE, ("dhcp_server_start(): could not obtain pcb\n"));
+        return ERR_MEM;
+    }
+
+    ip_set_option(dhcp_server->pcb, SOF_BROADCAST);
+    /* set up local and remote port for the pcb */
+    udp_bind(dhcp_server->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
+    //udp_connect(dhcp_server->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
+    /* set up the recv callback and argument */
+    udp_recv(dhcp_server->pcb, dhcp_server_recv, dhcp_server);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_server_start(): starting DHCP server\n"));
+
+    return ERR_OK;
+}
+
+
+void dhcpd_start(const char *netif_name)
+{
+    struct netif *netif = netif_list;
+    err_t res;
+
+    DEBUG_PRINTF("%s: %s\r\n", __FUNCTION__, netif_name);
+
+    LWIP_NETIF_LOCK();
+    if (strlen(netif_name) > sizeof(netif->name))
+    {
+        DEBUG_PRINTF("network interface name too long!\r\n");
+        goto _exit;
+    }
+
+    while (netif != RT_NULL)
+    {
+        if (strncmp(netif_name, netif->name, sizeof(netif->name)) == 0)
+            break;
+
+        netif = netif->next;
+        if (netif == RT_NULL)
+        {
+            DEBUG_PRINTF("network interface: %s not found!\r\n", netif_name);
+            break;
+        }
+    }
+
+    if (netif == RT_NULL)
+    {
+        goto _exit;
+    }
+
+    if (1)
+    {
+        extern void set_if(const char *netif_name, const char *ip_addr, const char *gw_addr, const char *nm_addr);
+
+        dhcp_stop(netif);
+
+        set_if(netif_name, DHCPD_SERVER_IP, "0.0.0.0", "255.255.255.0");
+
+        netif_set_up(netif);
+    }
+
+    {
+        char str_tmp[4 * 4 + 4] = DHCPD_SERVER_IP;
+        char *p = str_tmp;
+        ip4_addr_t ip_start, ip_end;
+
+        p = strchr(str_tmp, '.');
+        if (p)
+        {
+            p = strchr(p + 1, '.');
+            if (p)
+            {
+                p = strchr(p + 1, '.');
+            }
+        }
+        if (!p)
+        {
+            DEBUG_PRINTF("DHCPD_SERVER_IP: %s error!\r\n", str_tmp);
+            goto _exit;
+        }
+        p = p + 1; /* move to xxx.xxx.xxx.^ */
+
+        sprintf(p, "%d", DHCPD_CLIENT_IP_MIN);
+        ip4addr_aton(str_tmp, &ip_start);
+        DEBUG_PRINTF("ip_start: [%s]\r\n", str_tmp);
+        sprintf(p, "%d", DHCPD_CLIENT_IP_MAX);
+        ip4addr_aton(str_tmp, &ip_end);
+        DEBUG_PRINTF("ip_start: [%s]\r\n", str_tmp);
+
+        res = dhcp_server_start(netif, &ip_start, &ip_end);
+        if (res != 0)
+        {
+            DEBUG_PRINTF("dhcp_server_start res: %s.\r\n", res);
+        }
+    }
+
+_exit:
+    LWIP_NETIF_UNLOCK();
+    return;
+}
+
+