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/* $Cambridge: exim/exim-src/src/dcc.c,v 1.5 2009/11/12 08:34:23 nm4 Exp $ */
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/*************************************************
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* Exim - an Internet mail transport agent *
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*************************************************/
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/* Copyright (c) Wolfgang Breyha 2005-2009
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* Vienna University Computer Center
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* See the file NOTICE for conditions of use and distribution.
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/* This patch is based on code from Tom Kistners exiscan (ACL integration) and
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* the DCC local_scan patch from Christopher Bodenstein */
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/* Code for calling dccifd. Called from acl.c. */
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#ifdef EXPERIMENTAL_DCC
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uschar dcc_header_str[256];
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uschar dcc_result_str[256];
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/* This function takes a file descriptor and a buffer as input and
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* returns either 0 for success or errno in case of error. */
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int flushbuffer (int socket, uschar *buffer)
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rsp = write(socket, buffer, Ustrlen(buffer));
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debug_printf("Result of the write() = %d\n", rsp);
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debug_printf("Error writing buffer to socket: %s\n", strerror(errno));
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debug_printf("Wrote buffer to socket:\n%s\n", buffer);
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int dcc_process(uschar **listptr) {
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uschar *list = *listptr;
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uschar *dcc_daemon_ip = US"";
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uschar *dcc_default_ip_option = US"127.0.0.1";
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uschar *dcc_ip_option = US"";
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uschar *dcc_helo_option = US"localhost";
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uschar *dcc_reject_message = US"Rejected by DCC";
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uschar *xtra_hdrs = NULL;
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int i, j, k, c, retval, sockfd, resp, line;
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struct sockaddr_un serv_addr;
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struct sockaddr_in serv_addr_in;
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struct hostent *ipaddress;
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uschar sockip[40], client_ip[40];
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uschar rcpt[128], from[128];
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uschar dcc_return_text[1024];
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uschar mbox_path[1024];
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uschar message_subdir[2];
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struct header_line *dcchdr;
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uschar *dcc_acl_options;
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uschar dcc_acl_options_buffer[10];
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uschar dcc_xtra_hdrs[1024];
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if ((dcc_acl_options = string_nextinlist(&list, &sep,
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dcc_acl_options_buffer,
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sizeof(dcc_acl_options_buffer))) != NULL)
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/* parse 1st option */
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if ( (strcmpic(dcc_acl_options,US"false") == 0) ||
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(Ustrcmp(dcc_acl_options,"0") == 0) ) {
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/* explicitly no matching */
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/* special cases (match anything except empty) */
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if ( (strcmpic(dcc_acl_options,US"true") == 0) ||
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(Ustrcmp(dcc_acl_options,"*") == 0) ||
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(Ustrcmp(dcc_acl_options,"1") == 0) ) {
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dcc_acl_options = dcc_acl_options;
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/* empty means "don't match anything" */
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/* if we scanned this message last time, just return */
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/* open the spooled body */
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message_subdir[1] = '\0';
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for (i = 0; i < 2; i++) {
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message_subdir[0] = (split_spool_directory == (i == 0))? message_id[5] : 0;
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sprintf(CS mbox_path, "%s/input/%s/%s-D", spool_directory, message_subdir, message_id);
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data_file = Ufopen(mbox_path,"rb");
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if (data_file != NULL)
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if (data_file == NULL) {
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/* error while spooling */
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log_write(0, LOG_MAIN|LOG_PANIC,
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"dcc acl condition: error while opening spool file");
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/* Initialize the variables */
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bzero(sockip,sizeof(sockip));
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if (dccifd_address) {
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if (dccifd_address[0] == '/')
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Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
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if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2) {
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log_write(0, LOG_MAIN,
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"dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address);
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(void)fclose(data_file);
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/* opts is what we send as dccifd options - see man dccifd */
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/* We don't support any other option than 'header' so just copy that */
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bzero(opts,sizeof(opts));
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Ustrncpy(opts, "header", sizeof(opts)-1);
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Ustrncpy(client_ip, dcc_ip_option, sizeof(client_ip)-1);
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/* If the dcc_client_ip is not provided use the
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* sender_host_address or 127.0.0.1 if it is NULL */
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debug_printf("my_ip_option = %s - client_ip = %s - sender_host_address = %s\n", dcc_ip_option, client_ip, sender_host_address);
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if(!(Ustrcmp(client_ip, ""))){
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/* Do we have a sender_host_address or is it NULL? */
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if(sender_host_address){
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Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
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/* sender_host_address is NULL which means it comes from localhost */
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Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
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debug_printf("Client IP: %s\n", client_ip);
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Ustrncpy(sockip, dcc_daemon_ip, sizeof(sockip)-1);
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/* strncat(opts, my_request, strlen(my_request)); */
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Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
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Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1);
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Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2);
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/* initialize the other variables */
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dcchdr = header_list;
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/* we set the default return value to DEFER */
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bzero(sendbuf,sizeof(sendbuf));
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bzero(xhdr,sizeof(xhdr));
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bzero(rcpt,sizeof(rcpt));
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bzero(from,sizeof(from));
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/* send a null return path as "<>". */
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if (Ustrlen(sender_address) > 0)
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Ustrncpy(from, sender_address, sizeof(from));
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Ustrncpy(from, "<>", sizeof(from));
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Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1);
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/**************************************
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* Now creating the socket connection *
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**************************************/
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/* If there is a dcc_daemon_ip, we use a tcp socket, otherwise a UNIX socket */
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if(Ustrcmp(sockip, "")){
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ipaddress = gethostbyname((char *)sockip);
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bzero((char *) &serv_addr_in, sizeof(serv_addr_in));
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serv_addr_in.sin_family = AF_INET;
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bcopy((char *)ipaddress->h_addr, (char *)&serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
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serv_addr_in.sin_port = htons(portnr);
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if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){
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debug_printf("Creating socket failed: %s\n", strerror(errno));
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log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
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/* if we cannot create the socket, defer the mail */
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(void)fclose(data_file);
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/* Now connecting the socket (INET) */
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if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){
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debug_printf("Connecting socket failed: %s\n", strerror(errno));
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log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
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/* if we cannot contact the socket, defer the mail */
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(void)fclose(data_file);
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/* connecting to the dccifd UNIX socket */
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bzero((char *)&serv_addr,sizeof(serv_addr));
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serv_addr.sun_family = AF_UNIX;
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Ustrcpy(serv_addr.sun_path, sockpath);
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if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){
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debug_printf("Creating socket failed: %s\n", strerror(errno));
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log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
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/* if we cannot create the socket, defer the mail */
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(void)fclose(data_file);
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/* Now connecting the socket (UNIX) */
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if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){
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debug_printf("Connecting socket failed: %s\n", strerror(errno));
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log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
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/* if we cannot contact the socket, defer the mail */
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(void)fclose(data_file);
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/* the socket is open, now send the options to dccifd*/
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debug_printf("\n---------------------------\nSocket opened; now sending input\n-----------------\n");
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/* First, fill in the input buffer */
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Ustrncpy(sendbuf, opts, sizeof(sendbuf));
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Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
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debug_printf("opts = %s\nsender = %s\nrcpt count = %d\n", opts, from, recipients_count);
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debug_printf("Sending options:\n****************************\n");
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/* let's send each of the recipients to dccifd */
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for (i = 0; i < recipients_count; i++){
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debug_printf("recipient = %s\n",recipients_list[i].address);
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if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf))
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debug_printf("Writing buffer: %s\n", sendbuf);
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flushbuffer(sockfd, sendbuf);
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bzero(sendbuf, sizeof(sendbuf));
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Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
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Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
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/* send a blank line between options and message */
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Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
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/* Now we send the input buffer */
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debug_printf("%s\n****************************\n", sendbuf);
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flushbuffer(sockfd, sendbuf);
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/* now send the message */
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/* Clear the input buffer */
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bzero(sendbuf, sizeof(sendbuf));
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/* First send the headers */
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/* Now send the headers */
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debug_printf("Sending headers:\n****************************\n");
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Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
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while((dcchdr=dcchdr->next)) {
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if(dcchdr->slen > sizeof(sendbuf)-2) {
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/* The size of the header is bigger than the size of
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* the input buffer, so split it up in smaller parts. */
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flushbuffer(sockfd, sendbuf);
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bzero(sendbuf, sizeof(sendbuf));
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while(j < dcchdr->slen)
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for(i = 0; i < sizeof(sendbuf)-2; i++) {
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sendbuf[i] = dcchdr->text[j];
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flushbuffer(sockfd, sendbuf);
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bzero(sendbuf, sizeof(sendbuf));
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} else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) {
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flushbuffer(sockfd, sendbuf);
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bzero(sendbuf, sizeof(sendbuf));
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Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
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Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2);
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/* a blank line separates header from body */
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Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
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flushbuffer(sockfd, sendbuf);
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debug_printf("\n****************************\n%s", sendbuf);
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/* Clear the input buffer */
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bzero(sendbuf, sizeof(sendbuf));
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/* now send the body */
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debug_printf("Writing body:\n****************************\n");
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(void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
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while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) {
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flushbuffer(sockfd, sendbuf);
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bzero(sendbuf, sizeof(sendbuf));
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debug_printf("\n****************************\n");
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/* shutdown() the socket */
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if(shutdown(sockfd, 1) < 0){
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debug_printf("Couldn't shutdown socket: %s\n", strerror(errno));
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log_write(0,LOG_MAIN,"Couldn't shutdown socket: %s\n", strerror(errno));
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/* If there is a problem with the shutdown()
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(void)fclose(data_file);
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debug_printf("\n-------------------------\nInput sent.\n-------------------------\n");
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/********************************
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* receiving output from dccifd *
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********************************/
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debug_printf("\n-------------------------------------\nNow receiving output from server\n-----------------------------------\n");
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/******************************************************************
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* We should get 3 lines: *
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* 1/ First line is overall result: either 'A' for Accept, *
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* 'R' for Reject, 'S' for accept Some recipients or *
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* 'T' for a Temporary error. *
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* 2/ Second line contains the list of Accepted/Rejected *
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* recipients in the form AARRA (A = accepted, R = rejected). *
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* 3/ Third line contains the X-DCC header. *
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******************************************************************/
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line = 1; /* we start at the first line of the output */
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j = 0; /* will be used as index for the recipients list */
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k = 0; /* initializing the index of the X-DCC header: xhdr[k] */
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/* Let's read from the socket until there's nothing left to read */
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bzero(recvbuf, sizeof(recvbuf));
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while((resp = read(sockfd, recvbuf, sizeof(recvbuf)-1)) > 0) {
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/* How much did we get from the socket */
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c = Ustrlen(recvbuf) + 1;
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debug_printf("Length of the output buffer is: %d\nOutput buffer is:\n------------\n%s\n-----------\n", c, recvbuf);
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/* Now let's read each character and see what we've got */
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for(i = 0; i < c; i++) {
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/* First check if we reached the end of the line and
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* then increment the line counter */
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if(recvbuf[i] == '\n') {
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/* The first character of the first line is the
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* overall response. If there's another character
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* on that line it is not correct. */
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/* Now get the value and set the
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* return value accordingly */
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if(recvbuf[i] == 'A') {
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debug_printf("Overall result = A\treturning OK\n");
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Ustrcpy(dcc_return_text, "Mail accepted by DCC");
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else if(recvbuf[i] == 'R') {
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debug_printf("Overall result = R\treturning FAIL\n");
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if(sender_host_name) {
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log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address);
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log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address);
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Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1);
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else if(recvbuf[i] == 'S') {
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debug_printf("Overall result = S\treturning OK\n");
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Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC");
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/* Since we're in an ACL we want a global result
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* so we accept for all */
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else if(recvbuf[i] == 'G') {
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debug_printf("Overall result = G\treturning FAIL\n");
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Ustrcpy(dcc_return_text, "Greylisted by DCC");
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else if(recvbuf[i] == 'T') {
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debug_printf("Overall result = T\treturning DEFER\n");
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log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf);
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Ustrcpy(dcc_return_text, "Temporary error with DCC");
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debug_printf("Overall result = something else\treturning DEFER\n");
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log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf);
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Ustrcpy(dcc_return_text, "Unknown DCC response");
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/* We're on the first line but not on the first character,
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* there must be something wrong. */
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debug_printf("Line = %d but i = %d != 0 character is %c - This is wrong!\n", line, i, recvbuf[i]);
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log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf);
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/* On the second line we get a list of
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* answer for each recipient. We don't care about
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* it because we're in an acl and so just take the
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/* The third and following lines is the X-DCC header,
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* so we store it in xhdr. */
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/* check if we don't get more than what we can handle */
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if(k < sizeof(xhdr)) { /* xhdr has a length of 120 */
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xhdr[k] = recvbuf[i];
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debug_printf("We got more output than we can store in the X-DCC header. Truncating at 120 characters.\n");
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/* Wrong line number. There must be a problem with the output. */
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debug_printf("Wrong line number in output. Line number is %d\n", line);
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/* we reinitialize the output buffer before we read again */
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bzero(recvbuf,sizeof(recvbuf));
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/* We have read everything from the socket */
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/* We need the terminate the X-DCC header with a '\n' character. This needs to be k-1
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* for xhdr[k] contains '\0'. */
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/* Now let's sum up what we've got. */
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debug_printf("\n--------------------------\nOverall result = %d\nX-DCC header: %sReturn message: %s\ndcc_result: %s\n", retval, xhdr, dcc_return_text, dcc_result);
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/* We only add the X-DCC header if it starts with X-DCC */
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if(!(Ustrncmp(xhdr, "X-DCC", 5))){
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if(dcc_direct_add_header) {
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header_add(' ' , "%s", xhdr);
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/* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
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debug_printf("Wrong format of the X-DCC header: %s\n", xhdr);
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/* check if we should add additional headers passed in acl_m_dcc_add_header */
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if(dcc_direct_add_header) {
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if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) {
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Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2);
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if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n')
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Ustrcat(dcc_xtra_hdrs, "\n");
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header_add(' ', "%s", dcc_xtra_hdrs);
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debug_printf("adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs);
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/* Now return to exim main process */
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debug_printf("Before returning to exim main process:\nreturn_text = %s - retval = %d\ndcc_result = %s\n", dcc_return_text, retval, dcc_result);
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(void)fclose(data_file);
added
removed
src/dcc.c
