原文：http://apps.hi.baidu.com/share/detail/18176963

#ifdef WIN32

#include

#include

#else

#include

#include

#include

#include

#include

#include

#include

#endif

struct data6

{

unsigned int d4:6;

unsigned int d3:6;

unsigned int d2:6;

unsigned int d1:6;

};

// 协议中加密部分使用的是base64方法

char con628(char c6);

void base64(char *dbuf,char *buf128,int len);

void sendemail(char *email,char *body);

int open_socket(struct sockaddr *addr);

int main()

{

char email[] = "987654321@qq.com";

char body[] = "From: \"lucy\"<123456789@qq.com>\r\n"

"To: \"dasiy\"<987654321@qq.com>\r\n"

"Subject: Hello\r\n\r\n"

"Hello World, Hello Email!";

sendemail(email, body);

return 0;

}

char con628(char c6)

{

char rtn = '\0';

if (c6 < 26) rtn = c6 + 65;

else if (c6 < 52) rtn = c6 + 71;

else if (c6 < 62) rtn = c6 - 4;

else if (c6 == 62) rtn = 43;

else rtn = 47;

return rtn;

}

// base64的实现

void base64(char *dbuf, char *buf128, int len)

{

struct data6 *ddd = NULL;

int i = 0;

char buf[256] = {0};

char *tmp = NULL;

char cc = '\0';

memset(buf, 0, 256);

strcpy(buf, buf128);

for(i = 1; i <= len/3; i++)

{

tmp = buf+(i-1)*3;

cc = tmp[2];

tmp[2] = tmp[0];

tmp[0] = cc;

ddd = (struct data6 *)tmp;

dbuf[(i-1)*4+0] = con628((unsigned int)ddd->d1);

dbuf[(i-1)*4+1] = con628((unsigned int)ddd->d2);

dbuf[(i-1)*4+2] = con628((unsigned int)ddd->d3);

dbuf[(i-1)*4+3] = con628((unsigned int)ddd->d4);

}

if(len%3 == 1)

{

tmp = buf+(i-1)*3;

cc = tmp[2];

tmp[2] = tmp[0];

tmp[0] = cc;

ddd = (struct data6 *)tmp;

dbuf[(i-1)*4+0] = con628((unsigned int)ddd->d1);

dbuf[(i-1)*4+1] = con628((unsigned int)ddd->d2);

dbuf[(i-1)*4+2] = '=';

dbuf[(i-1)*4+3] = '=';

}

if(len%3 == 2)

{

tmp = buf+(i-1)*3;

cc = tmp[2];

tmp[2] = tmp[0];

tmp[0] = cc;

ddd = (struct data6 *)tmp;

dbuf[(i-1)*4+0] = con628((unsigned int)ddd->d1);

dbuf[(i-1)*4+1] = con628((unsigned int)ddd->d2);

dbuf[(i-1)*4+2] = con628((unsigned int)ddd->d3);

dbuf[(i-1)*4+3] = '=';

}

return;

}

// 发送邮件

void sendemail(char *email, char *body)

{

int sockfd = 0;

struct sockaddr_in their_addr = {0};

char buf[1500] = {0};

char rbuf[1500] = {0};

char login[128] = {0};

char pass[128] = {0};

#ifdef WIN32

WSADATA WSAData;

WSAStartup(MAKEWORD(2, 2), &WSAData);

#endif

memset(&their_addr, 0, sizeof(their_addr));

their_addr.sin_family = AF_INET;

their_addr.sin_port = htons(25);

their_addr.sin_addr.s_addr = inet_addr("112.90.141.71");//qq smtp 服务器

// 连接邮件服务器，如果连接后没有响应，则2 秒后重新连接

sockfd = open_socket((struct sockaddr *)&their_addr);

memset(rbuf,0,1500);

while(recv(sockfd, rbuf, 1500, 0) == 0)

{

printf("reconnect...\n");

Sleep(2);

//close(sockfd);

sockfd = open_socket((struct sockaddr *)&their_addr);

memset(rbuf,0,1500);

}

printf("%s\n", rbuf);

// EHLO

memset(buf, 0, 1500);

sprintf(buf, "EHLO abcdefg-PC\r\n");

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// AUTH LOGIN

memset(buf, 0, 1500);

sprintf(buf, "AUTH LOGIN\r\n");

send(sockfd, buf, strlen(buf), 0);

printf("%s\n", buf);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// USER

memset(buf, 0, 1500);

sprintf(buf,"12345678");//你的qq号

memset(login, 0, 128);

base64(login, buf, strlen(buf));

sprintf(buf, "%s\r\n", login);

send(sockfd, buf, strlen(buf), 0);

printf("%s\n", buf);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// PASSWORD

sprintf(buf, "qqpassword");//你的qq密码

memset(pass, 0, 128);

base64(pass, buf, strlen(buf));

sprintf(buf, "%s\r\n", pass);

send(sockfd, buf, strlen(buf), 0);

printf("%s\n", buf);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// MAIL FROM

memset(buf, 0, 1500);

sprintf(buf, "MAIL FROM: <123456789@qq.com>\r\n");

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// RCPT TO 第一个收件人

sprintf(buf, "RCPT TO:\r\n", email);

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// DATA 准备开始发送邮件内容

sprintf(buf, "DATA\r\n");

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// 发送邮件内容，\r\n.\r\n内容结束标记

sprintf(buf, "%s\r\n.\r\n", body);

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// QUIT

sprintf(buf, "QUIT\r\n");

send(sockfd, buf, strlen(buf), 0);

memset(rbuf, 0, 1500);

recv(sockfd, rbuf, 1500, 0);

printf("%s\n", rbuf);

// VC2005 需要使用

closesocket(sockfd);

//close(sockfd);

#ifdef WIN32

WSACleanup();

#endif

return;

}

// 打开TCP Socket连接

int open_socket(struct sockaddr *addr)

{

int sockfd = 0;

sockfd=socket(PF_INET, SOCK_STREAM, 0);

if(sockfd < 0)

{

fprintf(stderr, "Open sockfd(TCP) error!\n");

exit(-1);

}

if(connect(sockfd, addr, sizeof(struct sockaddr)) < 0)

{

fprintf(stderr, "Connect sockfd(TCP) error!\n");

exit(-1);

}

return sockfd;

}