【程序】在STM32单片机上用1700行代码实现基于LwIP 2.1.2协议栈raw API和FatFs文件系统的FTP服务器（20200703版）

本程序在LwIP 2.1.2协议栈上用raw API实现了一个FTP服务器。文件存储在Winbond的W25Q128 SPI Flash中，通过FatFs读写文件，建立了FAT文件系统，容量为16MB。程序只有1700多行代码，由头文件ftp.h和源文件ftpd.c组成。

主要特点： 1. 采用lwip的raw API实现，可以在裸机环境下运行，支持IPv6 2. 兼容Windows文件管理器和FileZilla FTP客户端 3. 实现了文件浏览、上传、下载、重命名、新建文件夹、删除文件夹和文件等基本FTP功能 4. 支持IPv4和IPv6的主动模式和被动模式。可以在FileZilla客户端中强制使用主动模式，主动模式下电脑必须要关闭防火墙才能访问FTP服务器 5. nettime.c实现了从互联网获取北京时间的功能，并保存到单片机的RTC实时时钟，不用担心通过FTP上传的文件没有日期和时间信息。时间服务器选择的是utcnist.colorado.edu，端口号为37

不足之处： 1. 没有用户权限配置功能，目前所有的用户（包括匿名用户）都能上传和下载文件 2. 暂不支持FileZilla中的断点续传功能 3. FileZilla无法自动检测编码，必须改为强制UTF-8，文件名才不会乱码

【STM32F107VC+DP83848+W25Q128+FTP程序】

程序下载地址：https://pan.baidu.com/s/1KECwLCFMJIj4wO_WDz0o-A（提取码：gk5t）

DP83848.c中的三个重要配置项：（1）ETH_REMAP：若ETH部分引脚被重映射到了PD口，则应配置为1，否则为0 （2）USE_MII：如果DP83848以太网收发芯片使用的是MII接口则应配置为1，使用RMII接口则应配置为0 （3）RESET_N引脚：DP83848芯片的复位引脚，本例程中接的是PB15，可以改成其他引脚 请根据开发板的情况，正确配置DP83848.c中的这三个项目。

DP83848芯片的RESET引脚最好接上外部下拉电阻，避免单片机PA8没有输出时钟时DP83848未处于复位状态，干扰电路正常运行。 启动文件startup_stm32f107xc.s中应该设置合适的栈大小Stack_Size，供FatFs使用。

HSE晶振的大小在项目属性的C/C++选项卡中的Preprocessor Symbols中的HSE_VALUE上设置。 本例程设置的是25000000，即25MHz。若修改了晶振大小，则还需修改common.c的clock_init时钟初始化函数。

【STM32F103RE+88W8801+W25Q128+FTP程序】

请参阅：https://blog.csdn.net/ZLK1214/article/details/107117885

【LwIP 2.0.3版本兼容性】

若要在2.0.3版本的lwip中运行，需要将2.1.2版本的pbuf_free_header和pbuf_remove_header函数复制过来，然后在ftpd.c顶部包含头文件<ctype.h>。

【BUG勘误】

1. Windows文件管理器中往FTP里面复制某些中文文件名的文件会失败。 这是由于Windows本身的BUG导致的，微软一直没有修复该BUG：https://social.technet.microsoft.com/Forums/en-US/6b4df752-51d1-42fb-baf1-8600fa0bdfc5/utf8-encoding-bug-report-about-using-ftp-with-windows-explorer Win7和Win10均有此BUG。往电脑上的FTP服务器上传文件后会出现问号，往本文的ftpd服务器上上传文件会直接提示失败。 FTP程序本身没有问题，fatfs的配置也没有问题。 要想上传中文文件名的文件，最好选择专业的FTP软件，如FileZilla。

2. tcp_accept函数没有对err参数做判断。当内存不足时收到新的FTP连接，整个程序就会卡死。 可通过FileZilla连续上传多个文件来复现此bug。串口输出如下：

ftpd_data_sent_list: paused! sndbuf=24, slen=62 [Send] len=590 [Recv] len=60 ftpd_sent: 39 bytes of response sent ftpd_sent: processed 6 bytes ftpd_data_sent_list: paused! sndbuf=24, slen=62 [Recv] len=66 FTPD accepted [233.2.0.8]:755! 220 LwIP FTP Service Assertion "tcp_write: invalid pcb" failed at line 414 in lwip-2.1.2\core\tcp_out.c SIGABRT: Abnormal termination Exited! returncode=1

在lwip中，tcp_accept回调函数的newpcb参数有可能为NULL，此时err参数为ERR_MEM。所以回调函数中必须要先判断err是否为ERR_OK，才能执行后面的操作。

解决方案是在ftpd_accept和ftpd_data_accept函数的最开头，添加如下判断：

if (err != ERR_OK) return err;

修改后的文件的下载链接：https://pan.baidu.com/s/1PdY-jRxs3wUM8LjQ3Ohedg（提取码：v23k）

【程序运行截图】

1. 使用Windows文件管理器通过计算机名访问FTP服务器（已登录admin用户，密码为123456）

2. FTP登录界面

3. FileZilla访问FTP服务器（必须要开启强制UTF-8编码才能防止中文文件名乱码）

4. FileZilla上传文件

6. 通过板子的IPv6地址访问FTP服务器

【程序运行结果】

STM32F107VC ETH SystemCoreClock=72000000 LSI is ready! Failed to start ETH! MAC address: 00:80:E1:CD:9E:1A IPv6 link-local address: FE80::280:E1FF:FECD:9E1A SPI Flash: M=0xef, ID=0x17 SPI Flash: M=0xef, ID=0x4018 Disk is mounted! DP83848 interrupt occurred! status=0x2c20 Link is up! ETH is restarted! [Send] len=350 [Send] len=86 [Send] len=78 [Send] len=86 [Recv] len=60 [Recv] len=60 [Recv] len=60 [Send] len=350 [Recv] len=60 [Recv] len=60 [Send] len=86 [Recv] len=208 [Send] len=70 [Recv] len=142 [Send] len=86 [Recv] len=86 [Send] len=78 [Recv] len=590 [Send] len=350 [Recv] len=590 [Send] len=42 [Send] len=42 [Send] len=42 [Send] len=42 [Send] len=86 DHCP supplied address! IP address: 192.168.1.2 Subnet mask: 255.255.255.0 Default gateway: 192.168.1.1 IPv6 address 1: 2409:8A62:362:1050:280:E1FF:FECD:9E1A DNS Server: 192.168.1.1 [Send] len=42 Time server IP: not in cache! [Recv] len=60 [Send] len=80 [Recv] len=116 Time server IP: 128.138.140.44 Connecting to 128.138.140.44... [Send] len=58 [Recv] len=60 Connected! [Send] len=54 [Recv] len=208 [Recv] len=60 [Send] len=54 [Recv] len=60 Time from network: 2020-07-03 21:17:57 RTC is not updated! Connection to the time server is closed! [Send] len=54 [Recv] len=60 [Send] len=42 [Send] len=42 [Recv] len=60 [Send] len=42 [Recv] len=208 [Recv] len=60 [Recv] len=208 [Recv] len=208 [Recv] len=60 [Recv] len=140 [Recv] len=208 [Recv] len=140 [Recv] len=60 [Recv] len=208 [Recv] len=140 [Recv] len=208 [Recv] len=60 [Recv] len=208 [Recv] len=140 [Recv] len=140 [Recv] len=60 [Recv] len=208 [Recv] len=86 [Send] len=86 [Recv] len=86 [Send] len=78 [Recv] len=74 FTPD accepted [2409:8A62:362:1050:883B:55B0:939C:EE8]:54466! 220 LwIP FTP Service [Send] len=96 [Recv] len=208 [Send] len=96 [Recv] len=74 ftpd_sent: 22 bytes of response sent [Recv] len=90 ftpd_recv: received 16 bytes USER anonymous 331 Anonymous access allowed, send identity (e-mail name) as password. [Send] len=146 [Recv] len=74 ftpd_sent: 72 bytes of response sent ftpd_sent: processed 16 bytes [Recv] len=88 ftpd_recv: received 14 bytes PASS IEUser@ 230 Login successful. [Send] len=97 [Recv] len=88 [Send] len=74 [Recv] len=60 [Send] len=97 [Recv] len=74 ftpd_sent: 23 bytes of response sent ftpd_sent: processed 14 bytes [Recv] len=88 ftpd_recv: received 14 bytes opts utf8 on 200 Always in UTF8 mode. [Send] len=100 [Recv] len=74 ftpd_sent: 26 bytes of response sent ftpd_sent: processed 14 bytes [Recv] len=80 ftpd_recv: received 6 bytes syst 500 Unknown command. [Send] len=96 [Recv] len=80 [Send] len=74 [Recv] len=208 [Send] len=96 [Recv] len=74 ftpd_sent: 22 bytes of response sent ftpd_sent: processed 6 bytes [Recv] len=85 ftpd_recv: received 11 bytes site help 500 Unknown command. [Send] len=96 [Recv] len=85 [Send] len=74 [Recv] len=92 [Send] len=96 [Recv] len=74 ftpd_sent: 22 bytes of response sent ftpd_sent: processed 11 bytes [Recv] len=79 ftpd_recv: received 5 bytes PWD 257 "/" is the current directory. [Send] len=109 [Recv] len=74 ftpd_sent: 35 bytes of response sent ftpd_sent: processed 5 bytes [Recv] len=82 ftpd_recv: received 8 bytes TYPE A 200 Switching to ASCII mode. [Send] len=104 [Recv] len=82 [Send] len=74 [Recv] len=92 [Recv] len=60 [Recv] len=208 [Recv] len=92 [Send] len=104 [Recv] len=86 [Send] len=86 [Recv] len=208 [Recv] len=140 [Send] len=104 [Recv] len=74 ftpd_sent: 30 bytes of response sent ftpd_sent: processed 8 bytes [Recv] len=80 ftpd_recv: received 6 bytes EPSV 229 Entering Extended Passive Mode (|||57805|). [Send] len=123 [Recv] len=80 [Send] len=74 [Recv] len=140 [Recv] len=60 [Send] len=123 [Recv] len=74 ftpd_sent: 49 bytes of response sent ftpd_sent: processed 6 bytes [Recv] len=86 [Send] len=78 [Recv] len=74 FTPD data connection to [2409:8A62:362:1050:883B:55B0:939C:EE8]:54468 is established! [Recv] len=80 ftpd_recv: received 6 bytes LIST 150 Here comes the directory listing. [Send] len=113 [Recv] len=80 [Send] len=74 [Send] len=113 [Recv] len=74 ftpd_sent: 39 bytes of response sent ftpd_sent: processed 6 bytes 04-04-2020 08:18PM 9471 111110.xlsx 04-01-2020 11:26PM 934844 HeartOfCat_20200401.zip 05-18-2020 09:13PM 9236 pt32.xlsx 04-27-2020 09:57PM 917 test.c FTPD data connection [2409:8A62:362:1050:883B:55B0:939C:EE8]:54468 is shutdown by the server! [Send] len=295 226 Directory send OK. [Send] len=98 [Recv] len=74 ftpd_sent: 24 bytes of response sent [Recv] len=208 [Send] len=295 [Recv] len=74 [Recv] len=74 FTPD data connection [2409:8A62:362:1050:883B:55B0:939C:EE8]:54468 is closed by the client! [Send] len=74 [Recv] len=74 [Send] len=74 [Recv] len=60 [Recv] len=208

【主要代码】

ftpd.h：

#ifndef _FTPD_H #define _FTPD_H #ifndef FTPD_DEBUG #define FTPD_DEBUG LWIP_DBG_OFF #endif #define FTPD_PORT 21 // FTP服务器端口号 #define FTPD_PASV 1 // 是否允许使用PASV命令 // 命令处理过程中的异常情况 #define FTPD_CMDSTEP_CONNFAILED 0x1000 // 连接建立失败 #define FTPD_CMDSTEP_CONNABORTED 0x2000 // 连接建立成功但异常中止 #define FTPD_CMDSTEP_CONNSHUTDOWN 0x4000 // 连接建立成功后被客户端关闭 // FTP客户端状态位 #if FTPD_PASV #define FTPD_FLAG_PASSIVE 0x01 // 当前是否为被动模式 #endif #define FTPD_FLAG_CLOSE 0x02 // 收到客户端的TCP第一次挥手后, 请求发送第三次挥手 #define FTPD_FLAG_SHUTDOWN 0x04 // 请求发送TCP第一次挥手, 然后接收客户端第三次挥手 #define FTPD_FLAG_RENAME 0x08 // 是否正在重命名文件 #define FTPD_FLAG_AGAIN 0x10 // 当前FTP命令还没有执行完毕, 控制连接上的数据发送完毕后应继续回来处理 #define FTPD_FLAG_NEWDATACONN 0x20 // 数据连接已创建但还未连接上 #define FTPD_FLAG_TCPERROR 0x40 // TCP发送数据出错 // 数据连接关闭方式 #define FTPD_FREEDATA_ABORT 0 // 强行中止数据连接 #define FTPD_FREEDATA_CLOSE 1 // 关闭数据连接 (客户端已关闭) #define FTPD_FREEDATA_SHUTDOWN 2 // 关闭数据连接 (客户端未关闭) #ifndef MAX_PATH #define MAX_PATH 260 #endif struct ftpd_user { char *name; char *password; }; struct ftpd_account { struct ftpd_user user; char *rootpath; }; #ifdef FF_DEFINED struct ftpd_state { struct tcp_pcb *ctrlconn; struct tcp_pcb *dataconn; int dataport; char cmd[MAX_PATH + 20]; int cmdlen; char *cmdarg; int cmdstep; char last; char type; char path[MAX_PATH]; char rename[MAX_PATH]; struct ftpd_user user; int userid; int flags; int sent; // 未收到确认的已发送字节数 struct pbuf *queue; // 数据接收队列 void *dataout; int dataout_len; DIR *dp; FIL *fp; FILINFO *finfo; }; #else struct ftpd_state; #endif int ftpd_concat_path(char *buffer, int bufsize, const char *filename); int ftpd_file_exists(const char *path); #ifdef FF_DEFINED time_t ftpd_filetime(WORD fdate, WORD ftime, struct tm *ptm); #endif int ftpd_fullpath(const struct ftpd_state *state, char *buffer, int bufsize, const char *filename, char **puserpath); int ftpd_init(void); void *ftpd_memrchr(const void *s, int c, size_t n); int ftpd_simplify_path(char *path, int basepos); char *ftpd_strdup(const char *s); #endif

ftpd.c：（2021年1月7日版本）

/*************************** 基于LwIP raw API的FTP服务器***************************** ** 注意事项: ** 1. 使用FileZilla客户端连接FTP服务器时, 字符集应该选择"强制UTF-8" ** 不能选择"自动检测", 这样文件名才不会乱码 ** 2. 若想要移动文件, 可在文件管理器中使用"xxx/", "../"这样的语法重命名文件 ** 例如想要把"abc.txt"移动到当前目录的123目录下, 则可以将文件重命名为"123/abc.txt" ** 将"def.doc"移动到父目录的456文件夹下, 则应该重命名为"../456/def.doc" ** 3. 服务器使用FatFs读写磁盘文件 ** 如果出现HardFault错误, 则可能是startup_stm32*.s启动文件里面的Stack_Size值太小 ** 将其改大就可以解决问题 ************************************************************************************/ #include <ff.h> #include <lwip/tcp.h> #include <string.h> #include <time.h> #include "ftpd.h" static err_t ftpd_accept(void *arg, struct tcp_pcb *newpcb, err_t err); static void ftpd_change_user(struct ftpd_state *state, const char *newuser); static int ftpd_copy_cmd(struct ftpd_state *state); #if FTPD_PASV static err_t ftpd_data_accept(void *arg, struct tcp_pcb *newpcb, err_t err); #endif static void ftpd_data_check(struct ftpd_state *state); static err_t ftpd_data_connected(void *arg, struct tcp_pcb *tpcb, err_t err); static void ftpd_data_err(void *arg, err_t err); static err_t ftpd_data_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err); static err_t ftpd_data_sent(void *arg, struct tcp_pcb *tpcb, u16_t len); static err_t ftpd_data_sent_list(void *arg, struct tcp_pcb *tpcb, u16_t len); static err_t ftpd_data_sent_retr(void *arg, struct tcp_pcb *tpcb, u16_t len); static void ftpd_err(void *arg, err_t err); static void ftpd_free(struct ftpd_state *state); static err_t ftpd_free_data(struct ftpd_state *state, int option); static int ftpd_is_valid_user(struct ftpd_user *user, int *pid); static int ftpd_prepare_data(struct ftpd_state *state); static void ftpd_process_cmd(struct ftpd_state *state); static int ftpd_process_data_cmd(struct ftpd_state *state); static int ftpd_process_directory_cmd(struct ftpd_state *state); static int ftpd_process_file_cmd(struct ftpd_state *state); static int ftpd_process_opt_cmd(struct ftpd_state *state); static int ftpd_process_user_cmd(struct ftpd_state *state); static err_t ftpd_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err); static int ftpd_send_msg(struct ftpd_state *state, const char *s); static err_t ftpd_sent(void *arg, struct tcp_pcb *tpcb, u16_t len); // 用户列表以及对应的根目录 static const struct ftpd_account ftpd_users[] = { {{"anonymous", NULL}, "C:/public"}, // 匿名用户 {{"admin", "123456"}, "C:/"}, {{"test", "789123"}, "C:/test"} }; // 盘符可在ffconf.h中的FF_VOLUME_STRS处指定 static struct tcp_pcb *ftpd_tpcb; /* 控制连接收到新请求 */ static err_t ftpd_accept(void *arg, struct tcp_pcb *newpcb, err_t err) { struct ftpd_state *state; if (err != ERR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("FTPD failed to accept [%s]:%d! err=%d\n", ipaddr_ntoa(&newpcb->remote_ip), newpcb->remote_port, err)); return err; } state = mem_malloc(sizeof(struct ftpd_state)); if (state == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("FTPD failed to accept [%s]:%d!\n", ipaddr_ntoa(&newpcb->remote_ip), newpcb->remote_port)); tcp_abort(newpcb); return ERR_ABRT; } memset(state, 0, sizeof(struct ftpd_state)); state->ctrlconn = newpcb; state->dataport = -1; state->type = 'A'; strcpy(state->path, "/"); state->userid = -1; LWIP_DEBUGF(FTPD_DEBUG, ("FTPD accepted [%s]:%d!\n", ipaddr_ntoa(&newpcb->remote_ip), newpcb->remote_port)); ftpd_send_msg(state, "220 LwIP FTP Service\r\n"); tcp_arg(newpcb, state); tcp_err(newpcb, ftpd_err); tcp_recv(newpcb, ftpd_recv); tcp_sent(newpcb, ftpd_sent); return ERR_OK; } /* 改变用户名并清空密码 */ static void ftpd_change_user(struct ftpd_state *state, const char *newuser) { if (state->user.name != NULL) { mem_free(state->user.name); state->user.name = NULL; } if (state->user.password != NULL) { mem_free(state->user.password); state->user.password = NULL; } if (newuser != NULL) state->user.name = ftpd_strdup(newuser); } /* 将文件夹和文件名连接在一起形成新路径 */ // 将buffer和filename连接起来, 保存到buffer中, 同时保证字符串末尾不带斜杠(根目录除外); buffer的最大容量为bufsize // 成功时返回字符串的长度; 失败时返回-1且buffer中的内容不变 int ftpd_concat_path(char *buffer, int bufsize, const char *filename) { char *p; int addslash, fileabs, folderlen, namelen, len; // 找出字符串的连接位置, 并去掉buffer的尾斜杠和filename的首斜杠 if (filename != NULL && filename[0] == '/') { // 如果文件名是绝对路径, 则需要把文件夹路径改为根目录 fileabs = 1; filename++; // 去掉首斜杠 if (buffer[0] == '/') folderlen = 1; // 文件夹路径不带盘符时只保留根目录符号 (首斜杠) else { p = strchr(buffer, ':'); if (p != NULL) folderlen = p + 1 - buffer; // 文件夹路径带盘符时只保留盘符 else folderlen = 0; // 如果buffer是相对路径, 清空字符串 } } else { // 如果文件名不是绝对路径, 则可以直接在文件夹路径末尾连接上文件名 fileabs = 0; folderlen = strlen(buffer); if (folderlen > 1 && buffer[folderlen - 1] == '/') folderlen--; } // 去掉filename的尾斜杠 if (filename != NULL) namelen = strlen(filename); else namelen = 0; if (namelen != 0 && filename[namelen - 1] == '/') namelen--; // 计算字符串连接在一起后需要的缓冲区大小 if (folderlen == 0) addslash = fileabs; // 路径为空时加不加斜杠取决于文件名是不是绝对路径 else if (folderlen == 1 && buffer[0] == '/') addslash = 0; // 路径为斜杠时不加斜杠 else if (folderlen != 0 && buffer[folderlen - 1] == ':') addslash = 1; // 路径最后一个字符为冒号时要加斜杠 else if (namelen == 0) addslash = 0; // 文件名为空时不加斜杠 else addslash = 1; // 其他情况都要加斜杠 len = folderlen + addslash + namelen; // 连接后的长度 if (len >= bufsize) return -1; // 缓冲区不够 // 连接字符串 if (addslash) buffer[folderlen] = '/'; if (namelen != 0) memcpy(buffer + folderlen + addslash, filename, namelen); buffer[len] = '\0'; return len; } /* 将数据接收队列queue中的FTP命令字符串提取到state->cmd中, 并释放占用的pbuf内存 */ // 返回值: 0表示还没有收到完整命令; 1表示收到了完整命令; 2表示收到了完整命令, 但超过了缓冲区最大长度 // state->cmdlen表示已收到了当前命令多少个字符 (包括\r\n) static int ftpd_copy_cmd(struct ftpd_state *state) { char *c; int complete = 0; // 是否收到完整命令 int cnt = 0; // 本次复制的字符数 int i; struct pbuf *p; for (p = state->queue; p != NULL && complete == 0; p = p->next) { c = p->payload; for (i = 0; i < p->len && complete == 0; i++) { if (state->last == '\r' && *c == '\n') { if (state->cmdlen <= sizeof(state->cmd)) { state->cmd[state->cmdlen - 1] = '\0'; // 把\r替换成\0 complete = 1; } else complete = 2; } else { if (state->cmdlen < sizeof(state->cmd)) state->cmd[state->cmdlen] = *c; } state->cmdlen++; state->last = *c; c++; cnt++; } } state->queue = pbuf_free_header(state->queue, cnt); return complete; } #if FTPD_PASV /* 数据连接被动模式连接建立成功 */ static err_t ftpd_data_accept(void *arg, struct tcp_pcb *newpcb, err_t err) { struct ftpd_state *state = arg; if (err != ERR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("FTPD failed to accept [%s]:%d! err=%d\n", ipaddr_ntoa(&newpcb->remote_ip), newpcb->remote_port, err)); return err; } if (!ip_addr_cmp(&newpcb->remote_ip, &state->ctrlconn->remote_ip)) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_WARNING, ("%s: IP address mismatch!\n", __FUNCTION__)); tcp_abort(newpcb); return ERR_ABRT; } tcp_close(state->dataconn); // 关闭端口监听 state->dataconn = newpcb; tcp_err(newpcb, ftpd_data_err); return ftpd_data_connected(arg, newpcb, err); } #endif /* 检查数据连接是否未开始发送数据 */ // 这个函数应该在控制连接发送完开始信息后调用一次 static void ftpd_data_check(struct ftpd_state *state) { #if FTPD_PASV if (state->flags & FTPD_FLAG_PASSIVE) { // 在PASV模式下, 连接可能会在PASV命令执行完毕的时候就建立成功 // 但必须要等到数据传输命令(如LIST命令)的响应(如150响应)发送完毕后, 才能开始发送数据 if ((state->flags & FTPD_FLAG_NEWDATACONN) == 0) ftpd_data_sent(state, state->dataconn, 0); // PORT模式下不存在这个问题, 因为连接建立后就可以立即开始发送数据 } #endif } /* 数据连接主动模式建立成功 */ static err_t ftpd_data_connected(void *arg, struct tcp_pcb *tpcb, err_t err) { struct ftpd_state *state = arg; LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection to [%s]:%d is established!\n", ipaddr_ntoa(&tpcb->remote_ip), tpcb->remote_port)); state->flags &= ~FTPD_FLAG_NEWDATACONN; tcp_recv(tpcb, ftpd_data_recv); tcp_sent(tpcb, ftpd_data_sent); return ftpd_data_sent(arg, tpcb, 0); } /* 数据连接出错 */ static void ftpd_data_err(void *arg, err_t err) { struct ftpd_state *state = arg; LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_WARNING, ("FTPD data error! err=%d\n", err)); if (state != NULL) { state->dataconn = NULL; // 调用err回调函数时, tpcb已经被LwIP释放了, 所以不需要再次释放 ftpd_free_data(state, FTPD_FREEDATA_ABORT); if (state->flags & FTPD_FLAG_NEWDATACONN) { state->flags &= ~FTPD_FLAG_NEWDATACONN; state->cmdstep |= FTPD_CMDSTEP_CONNFAILED; ftpd_send_msg(state, "425 Failed to establish connection.\r\n"); } else { state->cmdstep |= FTPD_CMDSTEP_CONNABORTED; ftpd_process_cmd(state); } } } /* 数据连接收到数据 */ static err_t ftpd_data_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err) { struct ftpd_state *state = arg; struct pbuf *q; FRESULT fr; UINT bw; if (p != NULL) { if (state != NULL) { if (strcasecmp(state->cmd, "STOR") == 0) { LWIP_DEBUGF(FTPD_DEBUG, ("%s: %d bytes received\n", __FUNCTION__, p->tot_len)); for (q = p; q != NULL; q = q->next) { fr = f_write(state->fp, q->payload, q->len, &bw); if (bw != q->len) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: f_write() failed! fr=%d, q->len=%u, bw=%u\n", __FUNCTION__, fr, q->len, bw)); pbuf_free(p); err = ftpd_free_data(state, FTPD_FREEDATA_ABORT); state->cmdstep = FTPD_CMDSTEP_CONNABORTED; ftpd_process_cmd(state); return err; } } } } tcp_recved(tpcb, p->tot_len); pbuf_free(p); } else { if (state != NULL) { LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection [%s]:%d is shutdown by the client!\n", ipaddr_ntoa(&tpcb->remote_ip), tpcb->remote_port)); ftpd_free_data(state, FTPD_FREEDATA_CLOSE); // 通知命令处理函数, 数据连接已被客户端关闭 state->cmdstep |= FTPD_CMDSTEP_CONNSHUTDOWN; ftpd_process_cmd(state); } else LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection [%s]:%d is closed by the client!\n", ipaddr_ntoa(&tpcb->remote_ip), tpcb->remote_port)); } return ERR_OK; } static err_t ftpd_data_sent(void *arg, struct tcp_pcb *tpcb, u16_t len) { err_t err = ERR_OK; struct ftpd_state *state = arg; if (state != NULL) { if (strcasecmp(state->cmd, "LIST") == 0) err = ftpd_data_sent_list(arg, tpcb, len); else if (strcasecmp(state->cmd, "RETR") == 0) err = ftpd_data_sent_retr(arg, tpcb, len); } return err; } /* 发送文件列表 */ static err_t ftpd_data_sent_list(void *arg, struct tcp_pcb *tpcb, u16_t len) { char buffer[MAX_PATH + 100]; err_t err; int bufsize, loop, slen; struct ftpd_state *state = arg; struct tm tm; FRESULT fr; if (state->finfo == NULL) { loop = 2; state->finfo = mem_malloc(sizeof(FILINFO)); if (state->finfo == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc() failed!\n", __FUNCTION__)); goto err; } } else loop = 1; while (loop) { if (loop == 2) { // 读取下一个文件的信息 fr = f_readdir(state->dp, state->finfo); if (fr != FR_OK || state->finfo->fname[0] == '\0') { if (fr != FR_OK) LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: f_readdir() failed! fr=%d\n", __FUNCTION__, fr)); // 读取文件信息失败 // 列表发送完毕 ftpd_free_data(state, FTPD_FREEDATA_SHUTDOWN); state->cmdstep = 2; ftpd_process_cmd(state); break; } } if (strcmp(state->finfo->fname, ".") == 0 || strcmp(state->finfo->fname, "..") == 0) { LWIP_DEBUGF(FTPD_DEBUG, ("%s: jumping over \"%s\"\n", __FUNCTION__, state->finfo->fname)); continue; } ftpd_filetime(state->finfo->fdate, state->finfo->ftime, &tm); slen = strftime(buffer, sizeof(buffer), "%m-%d-%Y %I:%M%p ", &tm); if (state->finfo->fattrib & AM_DIR) strcpy(buffer + slen, "<DIR> "); else sprintf(buffer + slen, "%14u ", state->finfo->fsize); slen += 15; slen += sprintf(buffer + slen, "%s\r\n", state->finfo->fname); LWIP_ASSERT("slen < sizeof(buffer)", slen < sizeof(buffer)); bufsize = tcp_sndbuf(tpcb); if (bufsize >= slen) { LWIP_DEBUGF(FTPD_DEBUG, ("%s", buffer)); err = tcp_write(tpcb, buffer, slen, TCP_WRITE_FLAG_COPY); if (err != ERR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_write() failed! err=%d\n", __FUNCTION__, err)); goto err; } loop = 2; } else { // TCP滑动窗口不够了, 暂时退出, 等待前面的数据发送完毕 LWIP_DEBUGF(FTPD_DEBUG, ("%s: paused! sndbuf=%d, slen=%d\n", __FUNCTION__, bufsize, slen)); loop = 0; } } return ERR_OK; err: err = ftpd_free_data(state, FTPD_FREEDATA_ABORT); state->cmdstep = FTPD_CMDSTEP_CONNABORTED; ftpd_process_cmd(state); return err; } /* 发送文件内容 */ static err_t ftpd_data_sent_retr(void *arg, struct tcp_pcb *tpcb, u16_t len) { char buffer[30]; err_t err; struct ftpd_state *state = arg; unsigned int size; FRESULT fr; UINT br; // 等待上一段数据发送完毕 state->dataout_len -= len; if (state->dataout_len != 0) return ERR_OK; // 释放上一段数据占用的内存 if (state->dataout != NULL) { mem_free(state->dataout); state->dataout = NULL; } size = tcp_sndbuf(tpcb); LWIP_ASSERT("sndbuf != 0", size != 0); state->dataout = mem_malloc(size); if (state->dataout == NULL) { // 内存分配失败时改用buffer缓冲区 LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc() failed!\n", __FUNCTION__)); if (size > sizeof(buffer)) size = sizeof(buffer); } if (state->dataout != NULL) fr = f_read(state->fp, state->dataout, size, &br); else fr = f_read(state->fp, buffer, size, &br); if (fr != FR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: failed to read file! fr=%d\n", __FUNCTION__, fr)); goto err; } if (br < size) size = br; if (size > 0) { state->dataout_len = size; if (state->dataout != NULL) err = tcp_write(tpcb, state->dataout, size, 0); else err = tcp_write(tpcb, buffer, size, TCP_WRITE_FLAG_COPY); if (err != ERR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_write() failed! err=%d\n", __FUNCTION__, err)); goto err; } } if (f_eof(state->fp)) { // 文件发送完毕 ftpd_free_data(state, FTPD_FREEDATA_SHUTDOWN); state->cmdstep = 2; ftpd_process_cmd(state); } return ERR_OK; err: err = ftpd_free_data(state, FTPD_FREEDATA_ABORT); state->cmdstep = FTPD_CMDSTEP_CONNABORTED; ftpd_process_cmd(state); return err; } /* 控制连接出错 */ static void ftpd_err(void *arg, err_t err) { struct ftpd_state *state = arg; LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_WARNING, ("FTPD error! err=%d\n", err)); if (state != NULL) { state->ctrlconn = NULL; ftpd_free(state); } } /* 判断指定文件是否存在 */ // 如果是判断文件夹是否存在, 则字符串末尾不能有斜杠 int ftpd_file_exists(const char *path) { FRESULT fr; if (strcmp(path + 1, ":") == 0 || strcmp(path + 1, ":/") == 0) return 1; fr = f_stat(path, NULL); return fr == FR_OK; } /* 将文件时间转换为C标准格式 */ // 在STM32中, time_t是32位的无符号整数 (unsigned int) // 因为没有符号位, 所以time_t支持超过2038年的年份, 可以放心使用 time_t ftpd_filetime(WORD fdate, WORD ftime, struct tm *ptm) { memset(ptm, 0, sizeof(struct tm)); ptm->tm_year = ((fdate >> 9) & 0x7f) + 80; ptm->tm_mon = ((fdate >> 5) & 0x0f) - 1; ptm->tm_mday = fdate & 0x1f; ptm->tm_hour = (ftime >> 11) & 0x1f; ptm->tm_min = (ftime >> 5) & 0x3f; ptm->tm_sec = (ftime & 0x1f) << 1; // 如果ptm中的日期有误, 则这个函数能自动修正 // 否则如果输出了错误的日期, 那么Windows的文件管理器会错误地显示快捷方式图标 return mktime(ptm); } /* 关闭FTP控制连接和数据连接, 释放state结构体以及里面的成员占用的内存 */ static void ftpd_free(struct ftpd_state *state) { if (state == NULL) return; ftpd_free_data(state, FTPD_FREEDATA_ABORT); // 如果数据连接尚未关闭, 则强行中止 if (state->ctrlconn != NULL) { if (state->flags & FTPD_FLAG_CLOSE) LWIP_DEBUGF(FTPD_DEBUG, ("FTPD connection [%s]:%d is closed by the server!\n", ipaddr_ntoa(&state->ctrlconn->remote_ip), state->ctrlconn->remote_port)); else LWIP_DEBUGF(FTPD_DEBUG, ("FTPD connection [%s]:%d is shutdown by the server!\n", ipaddr_ntoa(&state->ctrlconn->remote_ip), state->ctrlconn->remote_port)); tcp_arg(state->ctrlconn, NULL); tcp_close(state->ctrlconn); state->ctrlconn = NULL; } ftpd_change_user(state, NULL); mem_free(state); } /* 关闭FTP数据连接并释放相关内存 */ // 关闭连接时通常将option设为FTPD_FREEDATA_SHUTDOWN // 只有在ftpd_data_recv(p=NULL)中才使用FTPD_FREEDATA_CLOSE static err_t ftpd_free_data(struct ftpd_state *state, int option) { err_t err = ERR_OK; if (state == NULL) return err; state->dataport = -1; if (state->dataconn != NULL) { tcp_arg(state->dataconn, NULL); // 连接关闭后, 回调函数仍有可能触发, 所以必须和state彻底脱离关系 #if FTPD_PASV if ((state->flags & FTPD_FLAG_PASSIVE) && (state->flags & FTPD_FLAG_NEWDATACONN)) { LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data pcb is removed!\n")); tcp_close(state->dataconn); } else { #endif if (option == FTPD_FREEDATA_ABORT) { LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection [%s]:%d is aborted!\n", ipaddr_ntoa(&state->dataconn->remote_ip), state->dataconn->remote_port)); tcp_abort(state->dataconn); err = ERR_ABRT; } else { if (option == FTPD_FREEDATA_CLOSE) LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection [%s]:%d is closed by the server!\n", ipaddr_ntoa(&state->dataconn->remote_ip), state->dataconn->remote_port)); else LWIP_DEBUGF(FTPD_DEBUG, ("FTPD data connection [%s]:%d is shutdown by the server!\n", ipaddr_ntoa(&state->dataconn->remote_ip), state->dataconn->remote_port)); tcp_close(state->dataconn); } #if FTPD_PASV } #endif state->dataconn = NULL; } if (state->dataout != NULL) { mem_free(state->dataout); state->dataout = NULL; state->dataout_len = 0; } // 只有文件夹成功打开了之后, 才可以将指针赋给state->dp if (state->dp != NULL) { f_closedir(state->dp); mem_free(state->dp); state->dp = NULL; } // 只有文件成功打开了之后, 才可以将指针赋给state->fp if (state->fp != NULL) { f_close(state->fp); mem_free(state->fp); state->fp = NULL; } if (state->finfo != NULL) { mem_free(state->finfo); state->finfo = NULL; } return err; } /* 将用户根文件夹路径(rootpath)、当前文件夹路径(state->path)和文件名(filename)连接起来, 放入buffer缓冲区中 */ // buffer的原有内容会被忽略并清空, bufsize为缓冲区的大小 // puserpath为输出参数, 其内容是以用户文件夹为根目录的文件路径 int ftpd_fullpath(const struct ftpd_state *state, char *buffer, int bufsize, const char *filename, char **puserpath) { int basepos, ret; // 在缓冲区中准备好用户文件夹的路径 if (state->userid == -1) return -1; // 未登录, 连接失败 basepos = strlen(ftpd_users[state->userid].rootpath); if (basepos + 1 > bufsize) return -1; // 缓冲区不够 strcpy(buffer, ftpd_users[state->userid].rootpath); // 获取相对于用户文件夹的文件路径 if (buffer[basepos - 1] == '/') basepos--; // 使userpath的第一个字符为斜杠 // 如果没有斜杠, 则userpath指向\0, 下面连接路径后可能会变成斜杠 if (puserpath != NULL) *puserpath = buffer + basepos; // 连接state->path字符串 if (filename == NULL || filename[0] != '/') { // filename不是以用户文件夹为根目录的绝对路径, 而是相对于state->path的相对路径 // 需要将rootpath, state->path和filename这三个字符串连在一起 // filename == NULL的情况可视为空字符串, 是相对路径 LWIP_ASSERT("state->path[0] == '/'", state->path[0] == '/'); // state->path的首字符始终为斜杠 ret = ftpd_concat_path(buffer, bufsize, state->path + 1); if (ret == -1) return -1; } else { // filename是以用户文件夹为根目录的绝对路径 // 跳过斜杠字符, 只将rootpath和不带首斜杠的filename连起来 filename++; } // 连接filename字符串 ret = ftpd_concat_path(buffer, bufsize, filename); if (ret == -1) return -1; ret = ftpd_simplify_path(buffer, basepos); if (puserpath != NULL && **puserpath == '\0') *puserpath = "/"; // 如果最终结果就是用户根目录, 那么应该用正斜杠表示, 而不是空字符串 return ret; } /* 判断输入的用户名和密码是否正确 */ static int ftpd_is_valid_user(struct ftpd_user *user, int *pid) { int i; int n = LWIP_ARRAYSIZE(ftpd_users); if (user->name == NULL) return 0; // 未输入用户名 for (i = 0; i < n; i++) { if (strcasecmp(user->name, ftpd_users[i].user.name) == 0) { if (pid != NULL) *pid = i; if (ftpd_users[i].user.password == NULL) return 1; // 任何密码都可以 else if (user->password != NULL && strcmp(user->password, ftpd_users[i].user.password) == 0) return 1; // 密码正确 else return 0; // 密码错误 } } return 0; // 用户名不存在 } /* 启动ftpd服务器 */ int ftpd_init(void) { err_t err; struct tcp_pcb *temp; if (ftpd_tpcb != NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_WARNING, ("%s: FTPD server is already started!\n", __FUNCTION__)); return -1; } temp = tcp_new(); if (temp == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_new() failed!\n", __FUNCTION__)); return -1; } err = tcp_bind(temp, IP_ANY_TYPE, FTPD_PORT); if (err != ERR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_bind() failed! err=%d\n", __FUNCTION__, err)); tcp_close(temp); return -1; } ftpd_tpcb = tcp_listen(temp); if (ftpd_tpcb == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_listen() failed!\n", __FUNCTION__)); tcp_close(temp); return -1; } temp = NULL; tcp_accept(ftpd_tpcb, ftpd_accept); return 0; } /* memchr的反向版本 */ void *ftpd_memrchr(const void *s, int c, size_t n) { const char *p = s; int i; for (i = n - 1; i >= 0; i--) { if (p[i] == c) return (void *)&p[i]; } return NULL; } /* 准备好数据连接 */ // 若函数返回-1, 则表示连接建立失败, 此时已发送了425消息, 不用再发送其他错误消息 static int ftpd_prepare_data(struct ftpd_state *state) { err_t err; int ret = -1; if (state->dataport == -1) { ftpd_send_msg(state, "425 Use PORT or PASV first.\r\n"); return -1; } #if FTPD_PASV if (state->flags & FTPD_FLAG_PASSIVE) { LWIP_ASSERT("state->dataconn != NULL", state->dataconn != NULL); ret = 0; } else { #endif LWIP_ASSERT("state->dataconn == NULL", state->dataconn == NULL); state->dataconn = tcp_new(); if (state->dataconn == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_new() failed!\n", __FUNCTION__)); goto end; } tcp_arg(state->dataconn, state); err = tcp_connect(state->dataconn, &state->ctrlconn->remote_ip, state->dataport, ftpd_data_connected); if (err == ERR_OK) { // 使用PORT模式时, 最好将电脑的防火墙关闭, 以免板子连不上电脑而出错 LWIP_DEBUGF(FTPD_DEBUG, ("FTPD is connecting to [%s]:%d...\n", ipaddr_ntoa(&state->ctrlconn->remote_ip), state->dataport)); tcp_err(state->dataconn, ftpd_data_err); state->flags |= FTPD_FLAG_NEWDATACONN; ret = 0; } else LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_connect() failed! err=%d\n", __FUNCTION__, err)); #if FTPD_PASV } #endif end: if (ret == -1) { ftpd_send_msg(state, "425 Failed to establish connection.\r\n"); if (state->dataconn != NULL) { tcp_arg(state->dataconn, NULL); tcp_close(state->dataconn); state->dataconn = NULL; state->dataport = -1; } } return ret; } /* 处理命令 */ static void ftpd_process_cmd(struct ftpd_state *state) { int ret; // 只有当上一个命令的所有回应都发送完毕时, 才开始处理下一条命令 if (state->sent != 0) return; else if (state->flags & FTPD_FLAG_TCPERROR) goto end; if ((state->flags & FTPD_FLAG_AGAIN) == 0) { // 上一条命令已执行完毕 if (state->flags & (FTPD_FLAG_CLOSE | FTPD_FLAG_SHUTDOWN)) { ftpd_free(state); return; } // 从接收队列中取出一条新命令 ret = ftpd_copy_cmd(state); if (ret == 0) return; // 命令不完整 LWIP_DEBUGF(FTPD_DEBUG, ("%s\n", state->cmd)); state->cmdstep = 0; // 当前是命令的第一步操作 if (ret == 2) { ftpd_send_msg(state, "500 Syntax error, command unrecognized.\r\n"); goto end; } // 提取出命令参数 state->cmdarg = strchr(state->cmd, ' '); if (state->cmdarg != NULL) *state->cmdarg++ = '\0'; else state->cmdarg = ""; } else { // 上一条命令未执行完毕, 虽然state->sent==0, 但还需要继续发送更多数据 // cmd和cmdarg不变, 命令可根据cmdstep的值决定当前是第几步操作 state->flags &= ~FTPD_FLAG_AGAIN; } // 处理各种命令 if (ftpd_process_user_cmd(state)) // 这个必须第一个处理 ; else if (ftpd_process_data_cmd(state)) ; else if (ftpd_process_directory_cmd(state)) ; else if (ftpd_process_file_cmd(state)) ; else if (ftpd_process_opt_cmd(state)) ; else ftpd_send_msg(state, "500 Unknown command.\r\n"); end: // TCP无法发送数据时, 强制关闭连接 if (state->sent == 0 && state->flags & FTPD_FLAG_TCPERROR) { state->flags = (state->flags & ~FTPD_FLAG_AGAIN) | FTPD_FLAG_SHUTDOWN; ftpd_free(state); } } /* 处理与数据连接有关的命令 */ static int ftpd_process_data_cmd(struct ftpd_state *state) { char ip[IPADDR_STRLEN_MAX]; int i, j, ret; int isport = 0; ip_addr_t ipaddr; #if FTPD_PASV char buffer[100]; err_t err; int ispasv = 0; struct tcp_pcb *newpcb; #endif #if LWIP_IPV6 if (IP_IS_V4_VAL(state->ctrlconn->remote_ip)) { #endif if (strcasecmp(state->cmd, "PORT") == 0) isport = 4; #if FTPD_PASV else if (strcasecmp(state->cmd, "PASV") == 0) ispasv = 4; #endif #if LWIP_IPV6 } else if (IP_IS_V6_VAL(state->ctrlconn->remote_ip)) { if (strcasecmp(state->cmd, "EPRT") == 0) isport = 6; #if FTPD_PASV else if (strcasecmp(state->cmd, "EPSV") == 0) ispasv = 6; #endif } #endif if (isport) { // 如果之前启动了PASV模式, 则关闭创建的监听连接 state->dataport = -1; #if FTPD_PASV if (state->flags & FTPD_FLAG_PASSIVE) { state->flags &= ~FTPD_FLAG_PASSIVE; if (state->dataconn != NULL) { tcp_close(state->dataconn); state->dataconn = NULL; } } #endif // 提取出IP地址 #if LWIP_IPV6 if (isport == 4) { #endif for (i = j = 0; i < sizeof(ip) && j < 4; i++) { if (isdigit(state->cmdarg[i])) ip[i] = state->cmdarg[i]; else if (state->cmdarg[i] == ',') { ip[i] = '.'; j++; } else break; } if (j != 4) goto porterr; ip[i - 1] = '\0'; #if LWIP_IPV6 } else { if (memcmp(state->cmdarg, "|2|", 3) != 0) goto porterr; for (i = 0; i < sizeof(ip); i++) { if (state->cmdarg[3 + i] == '|') break; ip[i] = state->cmdarg[3 + i]; } if (i == sizeof(ip)) goto porterr; ip[i] = '\0'; } #endif ret = ipaddr_aton(ip, &ipaddr); if (ret == 0 || !ip_addr_cmp(&ipaddr, &state->ctrlconn->remote_ip)) goto porterr; // 提取出端口号 #if LWIP_IPV6 if (isport == 4) { #endif ret = sscanf(state->cmdarg + i, "%d,%d", &i, &j); if (ret != 2) goto porterr; ret = i * 256 + j; #if LWIP_IPV6 } else { i = sscanf(state->cmdarg + 4 + i, "%d", &ret); if (i != 1) goto porterr; } #endif if (ret != 0 && ret < 65536) { state->dataport = ret; #if LWIP_IPV6 if (isport == 4) { #endif #if FTPD_PASV ftpd_send_msg(state, "200 PORT command successful. Consider using PASV.\r\n"); #else ftpd_send_msg(state, "200 PORT command successful.\r\n"); #endif #if LWIP_IPV6 } else ftpd_send_msg(state, "200 EPRT command successful.\r\n"); #endif return 1; } porterr: #if LWIP_IPV6 if (isport == 4) #endif ftpd_send_msg(state, "500 Illegal PORT command.\r\n"); #if LWIP_IPV6 else ftpd_send_msg(state, "500 Illegal EPRT command.\r\n"); #endif } #if FTPD_PASV else if (ispasv) { if (state->dataconn == NULL) { state->dataconn = tcp_new(); if (state->dataconn == NULL) goto pasverr; #if LWIP_IPV6 if (ispasv == 4) #endif err = tcp_bind(state->dataconn, IP_ADDR_ANY, 0); #if LWIP_IPV6 else err = tcp_bind(state->dataconn, IP6_ADDR_ANY, 0); #endif if (err != ERR_OK) goto pasverr; newpcb = tcp_listen(state->dataconn); if (newpcb == NULL) goto pasverr; state->dataconn = newpcb; tcp_arg(state->dataconn, state); tcp_accept(state->dataconn, ftpd_data_accept); state->dataport = state->dataconn->local_port; state->flags |= FTPD_FLAG_NEWDATACONN | FTPD_FLAG_PASSIVE; } #if LWIP_IPV6 if (ispasv == 4) { #endif ipaddr_ntoa_r(&state->ctrlconn->local_ip, ip, sizeof(ip)); for (i = 0; ip[i] != '\0'; i++) { if (ip[i] == '.') ip[i] = ','; } sprintf(buffer, "227 Entering Passive Mode (%s,%d,%d).\r\n", ip, (state->dataport >> 8) & 0xff, state->dataport & 0xff); #if LWIP_IPV6 } else sprintf(buffer, "229 Entering Extended Passive Mode (|||%d|).\r\n", state->dataport); #endif ftpd_send_msg(state, buffer); return 1; pasverr: #if LWIP_IPV6 if (ispasv == 4) #endif ftpd_send_msg(state, "500 PASV command failed.\r\n"); #if LWIP_IPV6 else ftpd_send_msg(state, "500 EPSV command failed.\r\n"); #endif if (state->dataconn != NULL) { tcp_close(state->dataconn); state->dataconn = NULL; } } #endif else return 0; return 1; } static int ftpd_process_directory_cmd(struct ftpd_state *state) { char buffer[MAX_PATH]; char *path; int ret; DIR *dp = NULL; FRESULT fr; if (strcasecmp(state->cmd, "PWD") == 0) { ftpd_send_msg(state, "257 \""); ftpd_send_msg(state, state->path); ftpd_send_msg(state, "\" is the current directory.\r\n"); } else if (strcasecmp(state->cmd, "CWD") == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, &path); if (ret == -1) goto cwderr; else if (!ftpd_file_exists(buffer)) goto cwderr; strcpy(state->path, path); ftpd_send_msg(state, "250 Directory successfully changed.\r\n"); return 1; cwderr: ftpd_send_msg(state, "550 Failed to change directory.\r\n"); } else if (strcasecmp(state->cmd, "LIST") == 0) { if (state->cmdstep == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, NULL, NULL); if (ret == -1) goto listerr; LWIP_ASSERT("state->dp == NULL", state->dp == NULL); dp = mem_malloc(sizeof(DIR)); if (dp == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc(sizeof(DIR)) failed!\n", __FUNCTION__)); goto listerr; } fr = f_opendir(dp, buffer); if (fr != FR_OK) goto listerr; state->dp = dp; // 文件夹打开了之后才能赋给state->dp ret = ftpd_prepare_data(state); if (ret == -1) goto listerr2; state->cmdstep = 1; state->flags |= FTPD_FLAG_AGAIN; ftpd_send_msg(state, "150 Here comes the directory listing.\r\n"); return 1; listerr: state->cmdstep = FTPD_CMDSTEP_CONNABORTED; listerr2: // 这里涉及到两个不同的操作 // 一个是关闭文件夹, 另一个是释放存储文件夹信息的内存 if (state->dp != NULL) { f_closedir(state->dp); state->dp = NULL; } if (dp != NULL) { mem_free(dp); dp = NULL; } } else if (state->cmdstep == 1) { state->flags |= FTPD_FLAG_AGAIN; ftpd_data_check(state); } else if (state->cmdstep == 2) ftpd_send_msg(state, "226 Directory send OK.\r\n"); if (state->cmdstep & (FTPD_CMDSTEP_CONNABORTED | FTPD_CMDSTEP_CONNSHUTDOWN)) ftpd_send_msg(state, "450 Failed to list the folder.\r\n"); } else if (strcasecmp(state->cmd, "MKD") == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, &path); if (ret != -1) { fr = f_mkdir(buffer); if (fr == FR_OK) { ftpd_send_msg(state, "257 \""); ftpd_send_msg(state, path); ftpd_send_msg(state, "\" created.\r\n"); return 1; } } ftpd_send_msg(state, "550 Create directory operation failed.\r\n"); } else if (strcasecmp(state->cmd, "RMD") == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret != -1) { fr = f_unlink(buffer); if (fr == FR_OK) { ftpd_send_msg(state, "250 Remove directory operation successful.\r\n"); return 1; } } ftpd_send_msg(state, "550 Remove directory operation failed.\r\n"); } else return 0; return 1; } /* 处理与文件有关的命令 */ static int ftpd_process_file_cmd(struct ftpd_state *state) { char buffer[MAX_PATH]; int ret; long size; FIL *fp = NULL; FRESULT fr; if (strcasecmp(state->cmd, "SIZE") == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret == -1) goto sizeerr; fp = mem_malloc(sizeof(FIL)); if (fp == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc(sizeof(FIL)) failed!\n", __FUNCTION__)); goto sizeerr; } fr = f_open(fp, buffer, FA_READ); if (fr != FR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: f_open() failed! fr=%d\n", __FUNCTION__, fr)); goto sizeerr; } size = f_size(fp); f_close(fp); mem_free(fp); sprintf(buffer, "213 %ld\r\n", size); ftpd_send_msg(state, buffer); return 1; sizeerr: ftpd_send_msg(state, "550 Could not get file size.\r\n"); if (fp != NULL) mem_free(fp); } else if (strcasecmp(state->cmd, "RETR") == 0) { if (state->cmdstep == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret == -1) goto retrerr; LWIP_ASSERT("state->fp == NULL", state->fp == NULL); fp = mem_malloc(sizeof(FIL)); if (fp == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc(sizeof(FIL)) failed!\n", __FUNCTION__)); goto retrerr; } fr = f_open(fp, buffer, FA_READ); if (fr != FR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: f_open() failed! fr=%d\n", __FUNCTION__, fr)); goto retrerr; } state->fp = fp; // 文件打开了之后才能赋给state->fp ret = ftpd_prepare_data(state); if (ret == -1) goto retrerr2; state->cmdstep = 1; state->flags |= FTPD_FLAG_AGAIN; sprintf(buffer, "150 Opening %s mode data connection for ", (state->type == 'I') ? "BINARY" : "ASCII"); ftpd_send_msg(state, buffer); ftpd_send_msg(state, state->cmdarg); size = f_size(state->fp); sprintf(buffer, " (%ld bytes).\r\n", size); ftpd_send_msg(state, buffer); return 1; retrerr: ftpd_send_msg(state, "550 Failed to open file.\r\n"); retrerr2: if (state->fp != NULL) { f_close(state->fp); state->fp = NULL; } if (fp != NULL) { mem_free(fp); fp = NULL; } } else if (state->cmdstep == 1) { state->flags |= FTPD_FLAG_AGAIN; ftpd_data_check(state); } else if (state->cmdstep == 2) ftpd_send_msg(state, "226 Transfer complete.\r\n"); else if (state->cmdstep & (FTPD_CMDSTEP_CONNSHUTDOWN | FTPD_CMDSTEP_CONNABORTED)) ftpd_send_msg(state, "451 Requested action aborted: local error in processing.\r\n"); } else if (strcasecmp(state->cmd, "STOR") == 0) { if (state->cmdstep == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret == -1) goto storerr; LWIP_ASSERT("state->fp == NULL", state->fp == NULL); fp = mem_malloc(sizeof(FIL)); if (fp == NULL) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: mem_malloc(sizeof(FIL)) failed!\n", __FUNCTION__)); goto storerr; } fr = f_open(fp, buffer, FA_CREATE_ALWAYS | FA_WRITE); if (fr != FR_OK) { LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: f_open() failed! fr=%d, path=\"%s\"\n", __FUNCTION__, fr, buffer)); goto storerr; } state->fp = fp; // 文件打开了之后才能赋给state->fp ret = ftpd_prepare_data(state); if (ret == -1) goto storerr2; state->cmdstep = 1; state->flags |= FTPD_FLAG_AGAIN; ftpd_send_msg(state, "150 Ok to send data.\r\n"); return 1; storerr: ftpd_send_msg(state, "550 Failed to open file.\r\n"); storerr2: if (state->fp != NULL) { f_close(state->fp); state->fp = NULL; } if (fp != NULL) { mem_free(fp); fp = NULL; } } else if (state->cmdstep == 1) { state->flags |= FTPD_FLAG_AGAIN; ftpd_data_check(state); } else if (state->cmdstep & FTPD_CMDSTEP_CONNSHUTDOWN) ftpd_send_msg(state, "226 Transfer complete.\r\n"); else if (state->cmdstep & FTPD_CMDSTEP_CONNABORTED) ftpd_send_msg(state, "451 Requested action aborted: local error in processing.\r\n"); } else if (strcasecmp(state->cmd, "DELE") == 0) { ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret != -1) { ret = f_unlink(buffer); if (ret == 0) { ftpd_send_msg(state, "250 Delete operation successful.\r\n"); return 1; } } ftpd_send_msg(state, "550 Delete operation failed.\r\n"); } else if (strcasecmp(state->cmd, "RNFR") == 0) { ret = ftpd_fullpath(state, state->rename, sizeof(state->rename), state->cmdarg, NULL); if (ret != -1) { state->flags |= FTPD_FLAG_RENAME; ftpd_send_msg(state, "350 Ready for RNTO.\r\n"); } else { state->flags &= ~FTPD_FLAG_RENAME; ftpd_send_msg(state, "550 RNFR command failed.\r\n"); } } else if (strcasecmp(state->cmd, "RNTO") == 0) { if ((state->flags & FTPD_FLAG_RENAME) == 0) { ftpd_send_msg(state, "503 RNFR required first.\r\n"); return 1; } state->flags &= ~FTPD_FLAG_RENAME; ret = ftpd_fullpath(state, buffer, MAX_PATH, state->cmdarg, NULL); if (ret != -1) { ret = f_rename(state->rename, buffer); if (ret == 0) { ftpd_send_msg(state, "250 Rename successful.\r\n"); return 1; } } ftpd_send_msg(state, "550 Rename failed.\r\n"); } else return 0; return 1; } /* 处理与服务器选项有关的命令 */ static int ftpd_process_opt_cmd(struct ftpd_state *state) { if (strcasecmp(state->cmd, "opts") == 0) { if (strcasecmp(state->cmdarg, "utf8 on") == 0) ftpd_send_msg(state, "200 Always in UTF8 mode.\r\n"); else ftpd_send_msg(state, "501 Option not understood.\r\n"); } else if (strcasecmp(state->cmd, "TYPE") == 0) { if (strcasecmp(state->cmdarg, "A") == 0) ftpd_send_msg(state, "200 Switching to ASCII mode.\r\n"); else if (strcasecmp(state->cmdarg, "I") == 0) ftpd_send_msg(state, "200 Switching to Binary mode.\r\n"); else { ftpd_send_msg(state, "500 Unrecognised TYPE command.\r\n"); return 1; } state->type = state->cmdarg[0]; } else if (strcasecmp(state->cmd, "noop") == 0) ftpd_send_msg(state, "200 NOOP ok.\r\n"); else return 0; return 1; } /* 处理与用户有关的命令 */ static int ftpd_process_user_cmd(struct ftpd_state *state) { int userid; if (strcasecmp(state->cmd, "USER") == 0) { if (state->userid != -1) ftpd_send_msg(state, "530 Can't change to another user.\r\n"); else { ftpd_change_user(state, state->cmdarg); if (strcasecmp(state->cmdarg, "ANONYMOUS") == 0 && ftpd_is_valid_user(&state->user, NULL)) ftpd_send_msg(state, "331 Anonymous access allowed, send identity (e-mail name) as password.\r\n"); else ftpd_send_msg(state, "331 Please specify the password.\r\n"); } } else if (strcasecmp(state->cmd, "PASS") == 0) { if (state->userid != -1) ftpd_send_msg(state, "230 Already logged in.\r\n"); else if (state->user.name == NULL) ftpd_send_msg(state, "503 Login with USER first.\r\n"); else { state->user.password = ftpd_strdup(state->cmdarg); if (ftpd_is_valid_user(&state->user, &userid)) { if (ftpd_file_exists(ftpd_users[userid].rootpath)) { state->userid = userid; ftpd_send_msg(state, "230 Login successful.\r\n"); } else { ftpd_change_user(state, NULL); ftpd_send_msg(state, "530 Please create the home directory \""); ftpd_send_msg(state, ftpd_users[userid].rootpath); ftpd_send_msg(state, "\" before logging in.\r\n"); } } else { ftpd_change_user(state, NULL); ftpd_send_msg(state, "530 Login incorrect.\r\n"); } } } else if (strcasecmp(state->cmd, "QUIT") == 0) { ftpd_send_msg(state, "221 Goodbye.\r\n"); state->flags |= FTPD_FLAG_SHUTDOWN; } else if (state->userid == -1) ftpd_send_msg(state, "530 Please login with USER and PASS.\r\n"); else return 0; return 1; } static err_t ftpd_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err) { struct ftpd_state *state = arg; if (p != NULL) { LWIP_DEBUGF(FTPD_DEBUG, ("%s: received %d bytes\n", __FUNCTION__, p->tot_len)); if (state->queue == NULL) state->queue = p; else pbuf_cat(state->queue, p); } else { if (state != NULL) { LWIP_DEBUGF(FTPD_DEBUG, ("FTPD connection [%s]:%d is shutdown by the client!\n", ipaddr_ntoa(&tpcb->remote_ip), tpcb->remote_port)); state->flags |= FTPD_FLAG_CLOSE; } else { LWIP_DEBUGF(FTPD_DEBUG, ("FTPD connection [%s]:%d is closed by the client!\n", ipaddr_ntoa(&tpcb->remote_ip), tpcb->remote_port)); return ERR_OK; } } ftpd_process_cmd(state); return ERR_OK; } /* 发送回应 */ static int ftpd_send_msg(struct ftpd_state *state, const char *s) { err_t err; int len; if (state->flags & FTPD_FLAG_TCPERROR) return -1; len = strlen(s); LWIP_DEBUGF(FTPD_DEBUG, ("%s", s)); LWIP_ASSERT("sndbuf >= len", tcp_sndbuf(state->ctrlconn) >= len); err = tcp_write(state->ctrlconn, s, len, TCP_WRITE_FLAG_COPY); if (err != ERR_OK) { state->flags |= FTPD_FLAG_TCPERROR; LWIP_DEBUGF(FTPD_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("%s: tcp_write() failed! err=%d\n", __FUNCTION__, err)); return -1; } state->sent += len; return len; } static err_t ftpd_sent(void *arg, struct tcp_pcb *tpcb, u16_t len) { struct ftpd_state *state = arg; LWIP_DEBUGF(FTPD_DEBUG, ("%s: %d bytes of response sent\n", __FUNCTION__, len)); if (state != NULL) { state->sent -= len; if (state->sent == 0) { if (state->cmdlen != 0) { LWIP_DEBUGF(FTPD_DEBUG, ("%s: processed %d bytes\n", __FUNCTION__, state->cmdlen)); tcp_recved(state->ctrlconn, state->cmdlen); state->cmdlen = 0; } ftpd_process_cmd(state); } } return ERR_OK; } /* 去除路径中的"./"和"../"以及"//" */ // path必须为绝对路径 (可以带盘符也可以不带盘符), 不允许为相对路径 // basepos是字符串中用户根目录末尾的斜杠的位置, 用于保证"../"在后退时不会退到用户根目录以外 // 比如"C:/foo/bar", 如果用户根目录是C:/foo, 那么basepos应该为6 int ftpd_simplify_path(char *path, int basepos) { char *base, *p, *pp, *q; int len; // 检查path是否为绝对路径 if (*path != '/') { p = strchr(path, '/'); if (p == NULL || *(p - 1) != ':') return -1; // path不允许为相对路径 } // 检查并修正basepos参数 len = strlen(path); if (basepos < 0) basepos = 0; else if (basepos > len) basepos = len; base = path + basepos; if (*base != '/' && *base != '\0') { base = strchr(base, '/'); if (base == NULL) base = path + len; basepos = base - path; } p = base; // 当前目录 pp = base; // 父目录 do { q = strchr(p + 1, '/'); if (q != NULL) { len = q - p; if (len == 1 || (len == 2 && memcmp(p, "/.", 2) == 0)) memmove(p, q, strlen(q) + 1); else if (len == 3 && memcmp(p, "/..", 3) == 0) { memmove(pp, q, strlen(q) + 1); p = pp; pp = ftpd_memrchr(base, '/', pp - base); if (pp == NULL) pp = p; } else { pp = p; p = q; } } else { len = strlen(p); if (len == 1 || (len == 2 && memcmp(p, "/.", 2) == 0)) { if (p == path || *(p - 1) == ':') p++; *p = '\0'; } else if (len == 3 && memcmp(p, "/..", 3) == 0) { if (pp == path || *(pp - 1) == ':') pp++; *pp = '\0'; } } } while (q != NULL); return 0; } /* 开辟一块内存空间, 用于长期保存局部变量中的字符串, 避免函数退出时局部变量失效 */ char *ftpd_strdup(const char *s) { char *p; int len; len = strlen(s) + 1; p = mem_malloc(len); if (p != NULL) memcpy(p, s, len); return p; }