socket错误号

发表于 分类于 阅读次数： 阅读次数： 本文字数： 6.7k 阅读时长 ≈ 6 分钟

socket编程中的出现的错误号基本含义：

1
2
3
4
5
6
7
#include <errno.h>
...
{
    ...
    ret = sendto(fd, msg, msgLen, 0, (struct sockaddr*)&un, size);
    printf("%d sendto errno:%d\n", getpid(), errno);
}

错误号—errno

1
2
3
4
5
6
7
8
9
10
11
12
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NUM 135
int main(void)
{
	int i;
	for (i = 0; i < NUM; i++) {
		printf("%d: %s\n", i, strerror(i));
	}
	return 0;
}
  • 结果：
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    0: Success
    1: Operation not permitted
    2: No such file or directory
    3: No such process
    4: Interrupted system call
    5: Input/output error
    6: No such device or address
    7: Argument list too long
    8: Exec format error
    9: Bad file descriptor
    10: No child processes
    11: Resource temporarily unavailable
    12: Cannot allocate memory
    13: Permission denied
    14: Bad address
    15: Block device required
    16: Device or resource busy
    17: File exists
    18: Invalid cross-device link
    19: No such device
    20: Not a directory
    21: Is a directory
    22: Invalid argument
    23: Too many open files in system
    24: Too many open files
    25: Inappropriate ioctl for device
    26: Text file busy
    27: File too large
    28: No space left on device
    29: Illegal seek
    30: Read-only file system
    31: Too many links
    32: Broken pipe
    33: Numerical argument out of domain
    34: Numerical result out of range
    35: Resource deadlock avoided
    36: File name too long
    37: No locks available
    38: Function not implemented
    39: Directory not empty
    40: Too many levels of symbolic links
    41: Unknown error 41
    42: No message of desired type
    43: Identifier removed
    44: Channel number out of range
    45: Level 2 not synchronized
    46: Level 3 halted
    47: Level 3 reset
    48: Link number out of range
    49: Protocol driver not attached
    50: No CSI structure available
    51: Level 2 halted
    52: Invalid exchange
    53: Invalid request descriptor
    54: Exchange full
    55: No anode
    56: Invalid request code
    57: Invalid slot
    58: Unknown error 58
    59: Bad font file format
    60: Device not a stream
    61: No data available
    62: Timer expired
    63: Out of streams resources
    64: Machine is not on the network
    65: Package not installed
    66: Object is remote
    67: Link has been severed
    68: Advertise error
    69: Srmount error
    70: Communication error on send
    71: Protocol error
    72: Multihop attempted
    73: RFS specific error
    74: Bad message
    75: Value too large for defined data type
    76: Name not unique on network
    77: File descriptor in bad state
    78: Remote address changed
    79: Can not access a needed shared library
    80: Accessing a corrupted shared library
    81: .lib section in a.out corrupted
    82: Attempting to link in too many shared libraries
    83: Cannot exec a shared library directly
    84: Invalid or incomplete multibyte or wide character
    85: Interrupted system call should be restarted
    86: Streams pipe error
    87: Too many users
    88: Socket operation on non-socket
    89: Destination address required
    90: Message too long
    91: Protocol wrong type for socket
    92: Protocol not available
    93: Protocol not supported
    94: Socket type not supported
    95: Operation not supported
    96: Protocol family not supported
    97: Address family not supported by protocol
    98: Address already in use
    99: Cannot assign requested address
    100: Network is down
    101: Network is unreachable
    102: Network dropped connection on reset
    103: Software caused connection abort
    104: Connection reset by peer
    105: No buffer space available
    106: Transport endpoint is already connected
    107: Transport endpoint is not connected
    108: Cannot send after transport endpoint shutdown
    109: Too many references: cannot splice
    110: Connection timed out
    111: Connection refused
    112: Host is down
    113: No route to host
    114: Operation already in progress
    115: Operation now in progress
    116: Stale file handle
    117: Structure needs cleaning
    118: Not a XENIX named type file
    119: No XENIX semaphores available
    120: Is a named type file
    121: Remote I/O error
    122: Disk quota exceeded
    123: No medium found
    124: Wrong medium type
    125: Operation canceled
    126: Required key not available
    127: Key has expired
    128: Key has been revoked
    129: Key was rejected by service
    130: Owner died
    131: State not recoverable
    132: Operation not possible due to RF-kill
    133: Memory page has hardware error
    134: Unknown error 134

宏定义

  • include/uapi/asm-generic/errno-base.h/_ASM_GENERIC_ERRNO_BASE_H
  • include/uapi/asm-generic/errno.h/_ASM_GENERIC_ERRNO_H

    Linux内核中的位置

111： ECONNREFUSED

A connect() on a stream socket found no one listening on the remote address.

From: man connect

  1. 拒绝连接。一般发生在连接建立时

    • 拔服务器端网线测试，客户端设置keep alive时，recv较快返回0， 先收到ECONNREFUSED (Connection refused)错误码，其后都是ETIMEOUT。

  2. an error returned from connect(), so it can only occur in a client(if a client is defined as the party that initiates the connection

场景：使用UDP在进程间socket通信，sendto发送消息时，返回错误，错误号为111.

对端的socket没有进行接收所致。

115: EINPROGRESS

The socket is nonblocking and the connection cannot be completed immediately. It is possible to select(2) or poll(2) for completion by selecting the socket for writing. After select(2) indicates writability, use getsockopt(2) to read the SO_ERROR option at level SOL_SOCKET to determine whether connect() completed successfully (SO_ERROR is zero) or unsuccessfully (SO_ERROR is one of the usual error codes listed here, explaining the reason for the failure).

From: man connect

  • 非阻塞的socket，connect调用后立即返回，连接过程还在执行

场景： TCP连接中进行connect错误后，返回值：-1，错误号：115

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
int connect_timeout(int fd, struct sockaddr_in *addr, unsigned int wait_seconds)
{
	int ret;
	socklen_t addrlen = sizeof(struct sockaddr_in);

	if (wait_seconds > 0)
		activate_nonblock(fd);	//设为非阻塞

	ret = connect(fd, (struct sockaddr*)addr, addrlen);
	if (ret < 0 && errno == EINPROGRESS) {
		struct timeval timeout;
		fd_set write_fdset;

		FD_ZERO(&write_fdset);
		FD_SET(fd, &write_fdset);

		timeout.tv_sec = wait_seconds;
		timeout.tv_usec = 0;

		do {
			ret = select(fd + 1, NULL, &write_fdset, NULL, &timeout);
		} while (ret < 0 && errno == EINTR);

		if (ret == 0) {
			ret = -1;
			errno = ETIMEDOUT;
			printf("%s:%d, select error[%d]:%s, ret=%d\n", __func__, __LINE__, errno, strerror(errno), ret);
		} else if (ret < 0) {
			printf("%s:%d, select error[%d]:%s, ret=%d\n", __func__, __LINE__, errno, strerror(errno), ret);
			return -1;
		} else if (ret == 1) {
			int err;
			socklen_t socklen = sizeof(err);
			ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &socklen);
			if (ret == -1) {
				printf("%s:%d, getsockopt error[%d]:%s, ret=%d\n", __func__, __LINE__, errno, strerror(errno), ret);
				return -1;
			}
			if (err == 0) {
				ret = 0; //success
			} else {
				errno = err;
				ret = -1;
				printf("%s:%d, getsockopt error[%d]:%s, ret=%d\n", __func__, __LINE__, errno, strerror(errno), ret);
			}
		}
	}
	if (wait_seconds > 0) {
		deactivate_nonblock(fd);	//设回阻塞
	}
	return ret;
}

int net_set_nonblocking(int sock)
{
    int flags, res;

    flags = fcntl(sock, F_GETFL, 0);
    if (flags < 0) {
        flags = 0;
    }

    res = fcntl(sock, F_SETFL, flags | O_NONBLOCK);
    if (res < 0) {
        printf("fcntl return err:%d!\n", res);
        return -1;
    }

    return 0;
}

4: EINTR

1
2
3
do {
    n = recv(new_fd, buff, 500, 0);
} while (n < 0 && errno == EINTR);

34: ERANGE

#define ERANGE 34 /* Math result not representable */ 结果无法表示

在socket连接中，server端关闭了该连接