setsocketopt在lwip中使用

setsocketopt函数用于设置和得到socket的各种参数和属性，常见的有地址复用、发送时间延时和接收时间延时等作用，具体的作用请参见MSDN。

今儿主要讨论的是setsocketopt函数直接在freertos_lwip STM32F2系列调用失败的原因，返回错误-1。为了明确问题，我们跟踪代码发现上一层返回的错误代码是0X5C== 92，参加如下错误列表：

#ifdef LWIP_PROVIDE_ERRNO


#define  EPERM         1  /* Operation not permitted */
#define  ENOENT        2  /* No such file or directory */
#define  ESRCH         3  /* No such process */
#define  EINTR         4  /* Interrupted system call */
#define  EIO           5  /* I/O error */
#define  ENXIO         6  /* No such device or address */
#define  E2BIG         7  /* Arg list too long */
#define  ENOEXEC       8  /* Exec format error */
#define  EBADF         9  /* Bad file number */
#define  ECHILD       10  /* No child processes */
#define  EAGAIN       11  /* Try again */
#define  ENOMEM       12  /* Out of memory */
#define  EACCES       13  /* Permission denied */
#define  EFAULT       14  /* Bad address */
#define  ENOTBLK      15  /* Block device required */
#define  EBUSY        16  /* Device or resource busy */
#define  EEXIST       17  /* File exists */
#define  EXDEV        18  /* Cross-device link */
#define  ENODEV       19  /* No such device */
#define  ENOTDIR      20  /* Not a directory */
#define  EISDIR       21  /* Is a directory */
#define  EINVAL       22  /* Invalid argument */
#define  ENFILE       23  /* File table overflow */
#define  EMFILE       24  /* Too many open files */
#define  ENOTTY       25  /* Not a typewriter */
#define  ETXTBSY      26  /* Text file busy */
#define  EFBIG        27  /* File too large */
#define  ENOSPC       28  /* No space left on device */
#define  ESPIPE       29  /* Illegal seek */
#define  EROFS        30  /* Read-only file system */
#define  EMLINK       31  /* Too many links */
#define  EPIPE        32  /* Broken pipe */
#define  EDOM         33  /* Math argument out of domain of func */
#define  ERANGE       34  /* Math result not representable */
#define  EDEADLK      35  /* Resource deadlock would occur */
#define  ENAMETOOLONG 36  /* File name too long */
#define  ENOLCK       37  /* No record locks available */
#define  ENOSYS       38  /* Function not implemented */
#define  ENOTEMPTY    39  /* Directory not empty */
#define  ELOOP        40  /* Too many symbolic links encountered */
#define  EWOULDBLOCK  EAGAIN  /* Operation would block */
#define  ENOMSG       42  /* No message of desired type */
#define  EIDRM        43  /* Identifier removed */
#define  ECHRNG       44  /* Channel number out of range */
#define  EL2NSYNC     45  /* Level 2 not synchronized */
#define  EL3HLT       46  /* Level 3 halted */
#define  EL3RST       47  /* Level 3 reset */
#define  ELNRNG       48  /* Link number out of range */
#define  EUNATCH      49  /* Protocol driver not attached */
#define  ENOCSI       50  /* No CSI structure available */
#define  EL2HLT       51  /* Level 2 halted */
#define  EBADE        52  /* Invalid exchange */
#define  EBADR        53  /* Invalid request descriptor */
#define  EXFULL       54  /* Exchange full */
#define  ENOANO       55  /* No anode */
#define  EBADRQC      56  /* Invalid request code */
#define  EBADSLT      57  /* Invalid slot */


#define  EDEADLOCK    EDEADLK


#define  EBFONT       59  /* Bad font file format */
#define  ENOSTR       60  /* Device not a stream */
#define  ENODATA      61  /* No data available */
#define  ETIME        62  /* Timer expired */
#define  ENOSR        63  /* Out of streams resources */
#define  ENONET       64  /* Machine is not on the network */
#define  ENOPKG       65  /* Package not installed */
#define  EREMOTE      66  /* Object is remote */
#define  ENOLINK      67  /* Link has been severed */
#define  EADV         68  /* Advertise error */
#define  ESRMNT       69  /* Srmount error */
#define  ECOMM        70  /* Communication error on send */
#define  EPROTO       71  /* Protocol error */
#define  EMULTIHOP    72  /* Multihop attempted */
#define  EDOTDOT      73  /* RFS specific error */
#define  EBADMSG      74  /* Not a data message */
#define  EOVERFLOW    75  /* Value too large for defined data type */
#define  ENOTUNIQ     76  /* Name not unique on network */
#define  EBADFD       77  /* File descriptor in bad state */
#define  EREMCHG      78  /* Remote address changed */
#define  ELIBACC      79  /* Can not access a needed shared library */
#define  ELIBBAD      80  /* Accessing a corrupted shared library */
#define  ELIBSCN      81  /* .lib section in a.out corrupted */
#define  ELIBMAX      82  /* Attempting to link in too many shared libraries */
#define  ELIBEXEC     83  /* Cannot exec a shared library directly */
#define  EILSEQ       84  /* Illegal byte sequence */
#define  ERESTART     85  /* Interrupted system call should be restarted */
#define  ESTRPIPE     86  /* Streams pipe error */
#define  EUSERS       87  /* Too many users */
#define  ENOTSOCK     88  /* Socket operation on non-socket */
#define  EDESTADDRREQ 89  /* Destination address required */
#define  EMSGSIZE     90  /* Message too long */
#define  EPROTOTYPE   91  /* Protocol wrong type for socket */
#define  ENOPROTOOPT  92  /* Protocol not available */
#define  EPROTONOSUPPORT 93  /* Protocol not supported */
#define  ESOCKTNOSUPPORT 94  /* Socket type not supported */
#define  EOPNOTSUPP      95  /* Operation not supported on transport endpoint */
#define  EPFNOSUPPORT    96  /* Protocol family not supported */
#define  EAFNOSUPPORT    97  /* Address family not supported by protocol */
#define  EADDRINUSE      98  /* Address already in use */
#define  EADDRNOTAVAIL   99  /* Cannot assign requested address */
#define  ENETDOWN       100  /* Network is down */
#define  ENETUNREACH    101  /* Network is unreachable */
#define  ENETRESET      102  /* Network dropped connection because of reset */
#define  ECONNABORTED   103  /* Software caused connection abort */
#define  ECONNRESET     104  /* Connection reset by peer */
#define  ENOBUFS        105  /* No buffer space available */
#define  EISCONN        106  /* Transport endpoint is already connected */
#define  ENOTCONN       107  /* Transport endpoint is not connected */
#define  ESHUTDOWN      108  /* Cannot send after transport endpoint shutdown */
#define  ETOOMANYREFS   109  /* Too many references: cannot splice */
#define  ETIMEDOUT      110  /* Connection timed out */
#define  ECONNREFUSED   111  /* Connection refused */
#define  EHOSTDOWN      112  /* Host is down */
#define  EHOSTUNREACH   113  /* No route to host */
#define  EALREADY       114  /* Operation already in progress */
#define  EINPROGRESS    115  /* Operation now in progress */
#define  ESTALE         116  /* Stale NFS file handle */
#define  EUCLEAN        117  /* Structure needs cleaning */
#define  ENOTNAM        118  /* Not a XENIX named type file */
#define  ENAVAIL        119  /* No XENIX semaphores available */
#define  EISNAM         120  /* Is a named type file */
#define  EREMOTEIO      121  /* Remote I/O error */
#define  EDQUOT         122  /* Quota exceeded */


#define  ENOMEDIUM      123  /* No medium found */
#define  EMEDIUMTYPE    124  /* Wrong medium type */

发现问题的原因在于协议不支持，那么我们就需要配置opt.文件使协议栈支持setsocketopt函数。

首先我们需要定义LWIP_TCPIP_CORE_LOCKING宏定义为真才能使能setsocketopt函数，具体代码如下：

#ifndef LWIP_TCPIP_CORE_LOCKING
//#define LWIP_TCPIP_CORE_LOCKING         0
#endif

修改为：

#ifndef LWIP_TCPIP_CORE_LOCKING
#define LWIP_TCPIP_CORE_LOCKING         1
#endif

使能setocketopt函数后我们需要使能这个函数的一些功能，例如使能地址复用功能那么需要将SO_REUSE宏定义定义为真

#ifndef SO_REUSE
#define SO_REUSE                        0
#endif

修改为：

#ifndef SO_REUSE
#define SO_REUSE                        1
#endif

例如使能发送超时功能那么需要将LWIP_SO_RCVTIMEO宏定义定义为真

#ifndef LWIP_SO_RCVTIMEO
//#define LWIP_SO_RCVTIMEO                0
#endif

修改为：

#ifndef LWIP_SO_RCVTIMEO
#define LWIP_SO_RCVTIMEO                1
#endif