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- #include <stdio.h>
- #include <stdlib.h>
- #include <signal.h>
- #include "utils.h"
- extern char m_buffer[4096];
- #define BANNER "220 " HOSTNAME " SMTP"
- #define HELOANSWER "250 " HOSTNAME
- #define CMDUNKNOWN "502 command unimplemented"
- #define DOMAINUNKNOWN "553 unknown domain"
- #define TEMPERROR "421 delivery error, please retry later"
- #define DEFERROR "521 permanent delivery error, do not retry"
- #define PORT 25
- #define fail() do { perror(__FILE__ ":"); exit(-1); } while(0);
- struct serverinfo
- {
- char *address;
- unsigned port;
- };
- unsigned long connid=0;
- struct serverinfo *get_server(char *domain)
- {
- char buffer[1024];
- unsigned long *longs;
- /* connect to mysql and get values */
- db=mysql_init(NULL);
- if(NULL==mysql_real_connect(db,DBHOST,DBUSER,DBPASS,DBNAME,0,NULL,0)) { fprintf(stderr,"%s\n",mysql_error(db)); mysql_close(db); return NULL; }
- /* clean string */
- escape(db,domain);
- /* generate sql */
- snprintf(buffer,sizeof buffer,"SELECT `host`,`port` FROM `domains` WHERE `domain`=\"%s\" ORDER BY RAND();",domain);
- /* query! */
- if(mysql_query(db,buffer)) { fprintf(stderr,"%s\n",mysql_error(db)); mysql_close(db); return NULL; }
- for(i=0;row=mysql_fetch_row(db);i++)
- {
- longs=mysql_fetch_lengths(row);
-
- }
- mysql_close(db);
- return NULL;
- }
- char *get_domain(char *line)
- {
- char *strtmp=NULL;
- char *buf=NULL;
- safestrdup(buf,strchr(line,'@')+1);
- safestrdup(strtmp,strtok(buf," \"><"));
- condfree(buf);
- return strtmp;
- }
- void handle_new_connection(unsigned long p_connid,int fd)
- {
- char *buf=NULL;
- char *from=NULL;
- char *to=NULL;
- char *domain=NULL;
- char *serveraddress=NULL;
- int fdin=-1;
- int fds[2];
- char databuffer[8192];
- int bytesread;
- int fdread,fdwrite;
- struct serverinfo *server;
- connid=p_connid;
- write_string(fd,BANNER);
- while(!socketeof(fd))
- {
- free_and_read_string(buf,fd);
- if(!cmp(buf,"HELO")||!cmp(buf,"EHLO"))
- write_string(fd,HELOANSWER);
- else if(!cmp(buf,"MAIL FROM"))
- {
- safestrdup(from,buf);
- write_string(fd,"250 Ok");
- }
- else if(!cmp(buf,"RCPT TO"))
- {
- safestrdup(to,buf);
- domain=get_domain(to);
- if(NULL==(server=get_server(domain)))
- {
- write_string(fd,DOMAINUNKNOWN);
- exit(-1);
- }
- condfree(domain);
- break;
- }
- else
- write_string(fd,CMDUNKNOWN);
- }
- if(-1==(fdin=create_connected_socket(server->address,server->port)))
- {
- write_string(fd,TEMPERROR);
- exit(-1);
- }
- do /* manage errors as we would do an exception, all in one point */
- {
- /* reproduce initial conversation on the new server */
- free_and_read_string(buf,fdin); /* read banner */
- write_string(fdin,"HELO " HOSTNAME); do { free_and_read_string(buf,fdin); } while('-'==buf[3]);
- write_string(fdin,from); do { free_and_read_string(buf,fdin); } while('-'==buf[3]);
- if(cmp(buf,"250")) { write_string(fd,DEFERROR); break; }
- write_string(fdin,to);
- /* now just copy data from one server to the other */
- while(1)
- {
- fds[0]=fd; fds[1]=fdin;
- can_read(fds,2,-1);
- if(can_read(&fd,1,0)) { fdread=fd; fdwrite=fdin; }
- else { fdread=fdin; fdwrite=fd; }
- bytesread=read(fdread,databuffer,sizeof(databuffer));
- if(bytesread<=0||write(fdwrite,databuffer,bytesread)<=0)
- {
- closeskt(fd);
- closeskt(fdin);
- break;
- }
- }
- }
- while(0);
- condfree(buf); condfree(to); condfree(from); closeskt(fd); closeskt(fdin);
- exit(0);
- }
- int main(int argc, char **argv)
- {
- int fd_server=-1,fd=-1;
- unsigned long conn=0;
- /* ignore dying child */
- signal(SIGCHLD,SIG_IGN);
- openlog("dist",0,LOG_MAIL);
- if(-1==(fd_server=create_listening_socket(PORT))) fail();
- while(-1!=(fd=accept(fd_server,NULL,0)))
- {
- debug("New connection!");
- ++conn;
- switch(fork())
- {
- case 0: closeskt(fd_server); handle_new_connection(conn,fd);
- case -1: fail();
- default: closeskt(fd);
- }
- }
- close(fd_server);
- closelog();
- exit(0);
- }
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