/* ----------------------------------------------------------------- * * - MailSMTP - Sends a SMTP-message through a SMTP server. - * * - By Andreas Westling - * * - - * * - License: Any free license (including Public Domain). - * * - - * * - Remove main() and win32_init() to use the mainsmtp()-function - * * - in your application. - * * - - * * - BSD/Linux: - * * - * Just compile. - * * - - * * - Solaris: - * * - * Link with -lsocket -lnsl. - * * - - * * - Windows: - * * - * Add -D_MAILSMTP_WIN32 to compilation command line. - * * - * Initialize winsock before calling this function. Can be - * * - done using this little function: - * * - int win32_init() { - * * - WORD wVersionRequested; - * * - WSADATA wsaData; - * * - wVersionRequested=MAKEWORD(1,1); - * * - if (WSAStartup(wVersionRequested,&wsaData) != 0) { - * * - return 1; - * * - } - * * - return 0; - * * - } - * * - * Remember to call WSACleanup() when you are finished with - * * - network operations. - * * - * Link with -lwsock32. - * * ----------------------------------------------------------------- */ #include #include #include #include #ifdef _MAILSMTP_WIN32 # include # define uint32_t int #else # include # include # include # include #endif #define MAILSMTP_PORT 25 /* Port to connect to. */ #define MAILSMTP_TIMEOUT 10 /* Timeout (seconds). */ #define MAILSMTP_STATUS_OK 250 #define MAILSMTP_STATUS_READY 220 #define MAILSMTP_STATUS_START_INPUT 354 int mailsmtp (char *server, char *from, char *to, char *subject, char *msg); #ifdef _MAILSMTP_WIN32 int win32_init () { WORD wVersionRequested; WSADATA wsaData; wVersionRequested = MAKEWORD (1, 1); if (WSAStartup (wVersionRequested, &wsaData) != 0) { return 1; } return 0; } #endif int main (void) { #ifdef _MAILSMTP_WIN32 win32_init (); #endif printf ("Returnvalue: %d\n", mailsmtp ("nonexisting-mailserver.com", "user@nonexisting-mailserver.com", "anotheruser@nonexisting-mailserver.com", "This is a subject", "This is a Testmail")); #ifdef _MAILSMTP_WIN32 WSACleanup (); #endif return 0; } /* ----------------------------------------------------------------- * * - mailsmtp(): char ptr * char ptr * char ptr * char ptr - * * - * char ptr -> int - * * - - * * - Sends a SMTP mail message. - * * - - * * - Input: server - SMTP server to use. - * * - from - Email-address to send from. - * * - to - Email-address to send to. - * * - subject - The subject. May be NULL. - * * - msg - The message. May be NULL. - * * - Output: (int) - 0 = Successful. - * * - 1 = Unable to contact SMTP - * * - server. - * * - 2 = SMTP server refused to - * * - accept message. - * * - 3 = Argument error. - * * - 4 = Out of memory. - * * ----------------------------------------------------------------- */ int mailsmtp (char *server, char *from, char *to, char *subject, char *msg) { struct sockaddr_in saddr; struct hostent *he; struct timeval tv; char *domain, *buf; int s, bufsize, len = 0, state, err; fd_set fd; saddr.sin_family = AF_INET; saddr.sin_port = htons (MAILSMTP_PORT); if (!server || !from || !to) { return 3; } /* Only 20 needed really but added some extra chars * in case of small changes in the code. */ bufsize = 32 + strlen (to); if (subject) bufsize += strlen (subject); if (msg) bufsize += strlen (msg); buf = malloc (bufsize); if (!buf) { return 4; } domain = strchr (from, '@'); if (!domain) { free (buf); return 3; } domain++; /* Lookup IP-address of server. */ if (!(he = gethostbyname (server))) { free (buf); return 1; } if ((s = socket (AF_INET, SOCK_STREAM, 0)) == -1) { free (buf); return 1; } saddr.sin_addr.s_addr = *(uint32_t *) he->h_addr_list[0]; /* Connect to server. */ if (connect (s, (struct sockaddr *)&saddr, sizeof (saddr)) == -1) { free (buf); return 1; } /* Commloop. */ for (state = 0; state < 6; state++) { /* Can we receive from server? */ FD_ZERO (&fd); FD_SET (s, &fd); tv.tv_sec = MAILSMTP_TIMEOUT; tv.tv_usec = 0; if (select (s + 1, &fd, NULL, NULL, &tv) < 1) { shutdown (s, 2); close (s); free (buf); return 2; } /* Receive status from server and check it. */ if (recv (s, buf, 3, 0) != 3) { free (buf); return 2; } buf[3] = 0; err = 0; switch (state) { case 1: case 2: case 3: case 5: /* Ok. */ err += atoi (buf) != MAILSMTP_STATUS_OK; break; case 0: /* Service ready greeting. */ err += atoi (buf) != MAILSMTP_STATUS_READY; break; case 4: /* Start mail input. */ err += atoi (buf) != MAILSMTP_STATUS_START_INPUT; default: break; } if (err) { shutdown (s, 2); close (s); free (buf); return 2; } /* Ignore everything after the status-number. */ do { FD_ZERO (&fd); FD_SET (s, &fd); tv.tv_sec = 0; tv.tv_usec = 10; err = select (s + 1, &fd, NULL, NULL, &tv); if (err < 0) { shutdown (s, 2); close (s); free (buf); return 2; } if (!err) { break; } if (recv (s, buf, 1, 0) < 1) { free (buf); return 2; } } while (1); /* Can we send to server? */ FD_ZERO (&fd); FD_SET (s, &fd); tv.tv_sec = MAILSMTP_TIMEOUT; tv.tv_usec = 0; if (select (s + 1, NULL, &fd, NULL, &tv) < 1) { shutdown (s, 2); close (s); free (buf); return 2; } /* Send command according to state. */ err = 0; switch (state) { case 0: /* Send domain hello. */ len = sprintf (buf, "HELO %s\x0d\x0a", domain); break; case 1: /* Send sender mail address. */ len = sprintf (buf, "MAIL FROM:<%s>\x0d\x0a", from); break; case 2: /* Send receiver mail address. */ len = sprintf (buf, "RCPT TO:<%s>\x0d\x0a", to); break; case 3: /* Initiate data transfer. */ len = sprintf (buf, "DATA\x0d\x0a"); break; case 4: /* Send message header, subject and message. */ if (subject && msg) { len = sprintf (buf, "To:%s\x0d\x0aSubject:%s\x0d\x0a\x0d\x0a%s\x0d\x0a.\x0d\x0a", to, subject, msg); } else if (msg) { len = sprintf (buf, "To:%s\x0d\x0aSubject:\x0d\x0a\x0d\x0a%s\x0d\x0a.\x0d\x0a", to, msg); } else if (subject) { len = sprintf (buf, "To:%s\x0d\x0aSubject:%s\x0d\x0a\x0d\x0a.\x0d\x0a", to, subject); } break; case 5: /* Quit transaction. */ len = sprintf (buf, "QUIT\x0d\x0a"); break; } err += (send (s, buf, len, 0) != len); if (err) { shutdown (s, 2); close (s); free (buf); return 2; } } shutdown (s, 2); close (s); free (buf); return 0; }