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/*
This file is part of libquickmail.
libquickmail is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
libquickmail is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with libquickmail. If not, see <http://www.gnu.org/licenses/>.
*/
#include "smtpsocket.h"
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#if _MSC_VER
#define va_copy(dst,src) ((dst) = (src))
#endif
////////////////////////////////////////////////////////////////////////
#define DEBUG_ERROR(errmsg)
static const char* ERRMSG_MEMORY_ALLOCATION_ERROR = "Memory allocation error";
////////////////////////////////////////////////////////////////////////
SOCKET socket_open (const char* smtpserver, unsigned int smtpport, char** errmsg)
{
struct in_addr ipv4addr;
SOCKET sock;
struct sockaddr_in remote_sock_addr;
static const struct linger linger_option = {-1, 2}; //linger 2 seconds when disconnecting
//determine IPv4 address of SMTP server
ipv4addr.s_addr = inet_addr(smtpserver);
if (ipv4addr.s_addr == INADDR_NONE) {
struct hostent* addr;
if ((addr = gethostbyname(smtpserver)) != NULL && (addr->h_addrtype == AF_INET && addr->h_length >= 1 && ((struct in_addr*)addr->h_addr)->s_addr != 0))
memcpy(&ipv4addr, addr->h_addr, sizeof(ipv4addr));
}
if (ipv4addr.s_addr == INADDR_NONE) {
if (errmsg)
*errmsg = "Unable to resolve SMTP server host name";
return INVALID_SOCKET;
}
//create socket
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET) {
if (errmsg)
*errmsg = "Error creating socket for SMTP connection";
return INVALID_SOCKET;
}
//connect
remote_sock_addr.sin_family = AF_INET;
remote_sock_addr.sin_port = htons(smtpport);
remote_sock_addr.sin_addr.s_addr = ipv4addr.s_addr;
if (connect(sock, (struct sockaddr*)&remote_sock_addr, sizeof(remote_sock_addr)) != 0) {
if (errmsg)
*errmsg = "Error connecting to SMTP server";
socket_close(sock);
return INVALID_SOCKET;
}
//set linger option
setsockopt(sock, SOL_SOCKET, SO_LINGER, (const char*)&linger_option, sizeof(linger_option));
return sock;
}
void socket_close (SOCKET sock)
{
#ifndef _WIN32
shutdown(sock, 2);
#else
closesocket(sock);
#endif
}
int socket_send (SOCKET sock, const char* buf, int len)
{
int total_sent = 0;
int l = 0;
if (sock == 0 || !buf)
return 0;
if (len < 0)
len = strlen(buf);
while (len > 0 && (l = send(sock, buf, len, 0)) < len) {
if (l == SOCKET_ERROR || l > len)
return (total_sent > 0 ? total_sent : -1);
total_sent += l;
buf += l;
len -= l;
}
return total_sent + l;
}
int socket_data_waiting (SOCKET sock, int timeoutseconds)
{
fd_set rfds;
struct timeval tv;
if (sock == 0)
return 0;
//make a set with only this socket
FD_ZERO(&rfds);
FD_SET(sock, &rfds);
//make a timeval with the supplied timeout
tv.tv_sec = timeoutseconds;
tv.tv_usec = 0;
//check the socket
return (select(1, &rfds, NULL, NULL, &tv) > 0);
}
char* socket_receive_smtp (SOCKET sock)
{
char* buf = NULL;
int bufsize = READ_BUFFER_CHUNK_SIZE;
int pos = 0;
int linestart;
int n;
if ((buf = (char*)malloc(bufsize)) == NULL) {
DEBUG_ERROR(ERRMSG_MEMORY_ALLOCATION_ERROR)
return NULL;
}
do {
//insert line break if response is multiple lines
if (pos > 0) {
buf[pos++] = '\n';
if (pos >= bufsize) {
char* newbuf;
if ((newbuf = (char*)realloc(buf, bufsize + READ_BUFFER_CHUNK_SIZE)) == NULL) {
free(buf);
DEBUG_ERROR(ERRMSG_MEMORY_ALLOCATION_ERROR)
return NULL;
}
buf = newbuf;
bufsize += READ_BUFFER_CHUNK_SIZE;
}
}
//add each character read until it is a line break
linestart = pos;
while ((n = recv(sock, buf + pos, 1, 0)) == 1) {
//detect optional carriage return (CR)
if (buf[pos] == '\r')
if (recv(sock, buf + pos, 1, 0) < 1)
return NULL;
//detect line feed (LF)
if (buf[pos] == '\n')
break;
//enlarge buffer if necessary
if (++pos >= bufsize) {
char* newbuf;
if ((newbuf = (char*)realloc(buf, bufsize + READ_BUFFER_CHUNK_SIZE)) == NULL) {
free(buf);
DEBUG_ERROR(ERRMSG_MEMORY_ALLOCATION_ERROR)
return NULL;
}
buf = newbuf;
bufsize += READ_BUFFER_CHUNK_SIZE;
}
}
//exit on error (e.g. if connection is closed)
if (n < 1)
return NULL;
} while (!isdigit(buf[linestart]) || !isdigit(buf[linestart + 1]) || !isdigit(buf[linestart + 2]) || buf[linestart + 3] != ' ');
buf[pos] = 0;
return buf;
}
int socket_get_smtp_code (SOCKET sock, char** message)
{
int code;
char* buf = socket_receive_smtp(sock);
if (!buf || strlen(buf) < 4 || (buf[3] != ' ' && buf[3] != '-')) {
free(buf);
return 999;
}
//get code
buf[3] = 0;
code = atoi(buf);
//get error message (if needed)
if (message /*&& code >= 400*/)
*message = strdup(buf + 4);
//clean up and return
free(buf);
return code;
}
int socket_smtp_command (SOCKET sock, FILE* debuglog, const char* template, ...)
{
char* message;
int statuscode;
//send command (if one is supplied)
if (template) {
va_list ap;
va_list aq;
char* cmd;
int cmdlen;
va_start(ap, template);
//construct command to send
va_copy(aq, ap);
cmdlen = vsnprintf(NULL, 0, template, aq);
va_end(aq);
if ((cmd = (char*)malloc(cmdlen + 3)) == NULL) {
DEBUG_ERROR(ERRMSG_MEMORY_ALLOCATION_ERROR)
if (debuglog)
fprintf(debuglog, "%s\n", ERRMSG_MEMORY_ALLOCATION_ERROR);
va_end(ap);
return 999;
}
vsnprintf(cmd, cmdlen + 1, template, ap);
//log command to send
if (debuglog)
fprintf(debuglog, "SMTP> %s\n", cmd);
//append CR+LF
strcpy(cmd + cmdlen, "\r\n");
cmdlen += 2;
//send command
statuscode = socket_send(sock, cmd, cmdlen);
//clean up
free(cmd);
va_end(ap);
if (statuscode < 0)
return 999;
}
//receive result
message = NULL;
statuscode = socket_get_smtp_code(sock, &message);
if (debuglog)
fprintf(debuglog, "SMTP< %i %s\n", statuscode, (message ? message : ""));
free(message);
return statuscode;
}
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