//	qmail-remote通過SMTP協議向遠程主機傳送郵件

#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include "sig.h"#include "stralloc.h"#include "substdio.h"#include "subfd.h"#include "scan.h"#include "case.h"#include "error.h"#include "auto_qmail.h"#include "control.h"#include "dns.h"#include "alloc.h"#include "quote.h"#include "ip.h"#include "ipalloc.h"#include "ipme.h"#include "gen_alloc.h"#include "gen_allocdefs.h"#include "str.h"#include "now.h"#include "exit.h"#include "constmap.h"#include "tcpto.h"#include "readwrite.h"#include "timeoutconn.h"#include "timeoutread.h"#include "timeoutwrite.h"#define HUGESMTPTEXT 5000#define PORT_SMTP 25 /* silly rabbit, /etc/services is for users */unsigned long port = PORT_SMTP;GEN_ALLOC_typedef(saa,stralloc,sa,len,a)GEN_ALLOC_readyplus(saa,stralloc,sa,len,a,i,n,x,10,saa_readyplus)static stralloc sauninit = {0};
//	用來指定qmail-remote程序與遠程郵件主機SMTP會話中的主機名stralloc helohost = {0};stralloc routes = {0};struct constmap maproutes;stralloc host = {0};stralloc sender = {0};saa reciplist = {0};struct ip_address partner;void out(s) char *s; { if (substdio_puts(subfdoutsmall,s) == -1) _exit(0); }void zero() { if (substdio_put(subfdoutsmall,"\0",1) == -1) _exit(0); }void zerodie() { zero(); substdio_flush(subfdoutsmall); _exit(0); }void outsafe(sa) stralloc *sa; { int i; char ch;for (i = 0;i < sa->len;++i) {ch = sa->s[i]; if (ch < 33) ch = '?'; if (ch > 126) ch = '?';if (substdio_put(subfdoutsmall,&ch,1) == -1) _exit(0); } }void temp_nomem() { out("ZOut of memory. (#4.3.0)\n"); zerodie(); }void temp_oserr() { out("Z\System resources temporarily unavailable. (#4.3.0)\n"); zerodie(); }void temp_noconn() { out("Z\Sorry, I wasn't able to establish an SMTP connection. (#4.4.1)\n"); zerodie(); }void temp_read() { out("ZUnable to read message. (#4.3.0)\n"); zerodie(); }void temp_dnscanon() { out("Z\CNAME lookup failed temporarily. (#4.4.3)\n"); zerodie(); }void temp_dns() { out("Z\Sorry, I couldn't find any host by that name. (#4.1.2)\n"); zerodie(); }void temp_chdir() { out("Z\Unable to switch to home directory. (#4.3.0)\n"); zerodie(); }void temp_control() { out("Z\Unable to read control files. (#4.3.0)\n"); zerodie(); }void perm_partialline() { out("D\SMTP cannot transfer messages with partial final lines. (#5.6.2)\n"); zerodie(); }void perm_usage() { out("D\I (qmail-remote) was invoked improperly. (#5.3.5)\n"); zerodie(); }void perm_dns() { out("D\Sorry, I couldn't find any host named ");outsafe(&host);out(". (#5.1.2)\n"); zerodie(); }void perm_nomx() { out("D\Sorry, I couldn't find a mail exchanger or IP address. (#5.4.4)\n");zerodie(); }void perm_ambigmx() { out("D\Sorry. Although I'm listed as a best-preference MX or A for that host,\n\it isn't in my control/locals file, so I don't treat it as local. (#5.4.6)\n");zerodie(); }void outhost(){  char x[IPFMT];  if (substdio_put(subfdoutsmall,x,ip_fmt(x,&partner)) == -1) _exit(0);}int flagcritical = 0;void dropped() {  out("ZConnected to ");  outhost();  out(" but connection died. ");  if (flagcritical) out("Possible duplicate! ");  out("(#4.4.2)\n");  zerodie();}
//	用來指定qmail-remote嘗試同一個遠程郵件主機建立一個SMTP會話的時間。默認值狀態下
//如果超出60秒沒有得到遠程郵件主機的回應，那么將斷開連接。int timeoutconnect = 60;int smtpfd;int timeout = 1200;int saferead(fd,buf,len) int fd; char *buf; int len;{  int r;  r = timeoutread(timeout,smtpfd,buf,len);  if (r <= 0) dropped();  return r;}int safewrite(fd,buf,len) int fd; char *buf; int len;{  int r;  r = timeoutwrite(timeout,smtpfd,buf,len);  if (r <= 0) dropped();  return r;}char inbuf[1024];substdio ssin = SUBSTDIO_FDBUF(read,0,inbuf,sizeof inbuf);char smtptobuf[1024];substdio smtpto = SUBSTDIO_FDBUF(safewrite,-1,smtptobuf,sizeof smtptobuf);char smtpfrombuf[128];substdio smtpfrom = SUBSTDIO_FDBUF(saferead,-1,smtpfrombuf,sizeof smtpfrombuf);stralloc smtptext = {0};void get(ch)char *ch;{  substdio_get(&smtpfrom,ch,1);  if (*ch != '\r')    if (smtptext.len < HUGESMTPTEXT)     if (!stralloc_append(&smtptext,ch)) temp_nomem();}unsigned long smtpcode(){  unsigned char ch;  unsigned long code;  if (!stralloc_copys(&smtptext,"")) temp_nomem();  get(&ch); code = ch - '0';  get(&ch); code = code * 10 + (ch - '0');  get(&ch); code = code * 10 + (ch - '0');  for (;;) {    get(&ch);    if (ch != '-') break;    while (ch != '\n') get(&ch);    get(&ch);    get(&ch);    get(&ch);  }  while (ch != '\n') get(&ch);  return code;}void outsmtptext(){  int i;   if (smtptext.s) if (smtptext.len) {    out("Remote host said: ");    for (i = 0;i < smtptext.len;++i)      if (!smtptext.s[i]) smtptext.s[i] = '?';    if (substdio_put(subfdoutsmall,smtptext.s,smtptext.len) == -1) _exit(0);    smtptext.len = 0;  }}void quit(prepend,append)char *prepend;char *append;{  substdio_putsflush(&smtpto,"QUIT\r\n");  /* waiting for remote side is just too ridiculous */  out(prepend);  outhost();  out(append);  out(".\n");  outsmtptext();  zerodie();}void blast(){  int r;  char ch;  for (;;) {    r = substdio_get(&ssin,&ch,1);    if (r == 0) break;    if (r == -1) temp_read();    if (ch == '.')      substdio_put(&smtpto,".",1);    while (ch != '\n') {      substdio_put(&smtpto,&ch,1);      r = substdio_get(&ssin,&ch,1);      if (r == 0) perm_partialline();      if (r == -1) temp_read();    }    substdio_put(&smtpto,"\r\n",2);  }   flagcritical = 1;  substdio_put(&smtpto,".\r\n",3);  substdio_flush(&smtpto);}stralloc recip = {0};void smtp(){  unsigned long code;  int flagbother;  int i;   if (smtpcode() != 220) quit("ZConnected to "," but greeting failed");   substdio_puts(&smtpto,"HELO ");  substdio_put(&smtpto,helohost.s,helohost.len);  substdio_puts(&smtpto,"\r\n");  substdio_flush(&smtpto);  if (smtpcode() != 250) quit("ZConnected to "," but my name was rejected");   substdio_puts(&smtpto,"MAIL FROM:<");  substdio_put(&smtpto,sender.s,sender.len);  substdio_puts(&smtpto,">\r\n");  substdio_flush(&smtpto);  code = smtpcode();  if (code >= 500) quit("DConnected to "," but sender was rejected");  if (code >= 400) quit("ZConnected to "," but sender was rejected");   flagbother = 0;  for (i = 0;i < reciplist.len;++i) {    substdio_puts(&smtpto,"RCPT TO:<");    substdio_put(&smtpto,reciplist.sa[i].s,reciplist.sa[i].len);    substdio_puts(&smtpto,">\r\n");    substdio_flush(&smtpto);    code = smtpcode();    if (code >= 500) {      out("h"); outhost(); out(" does not like recipient.\n");      outsmtptext(); zero();    }    else if (code >= 400) {      out("s"); outhost(); out(" does not like recipient.\n");      outsmtptext(); zero();    }    else {      out("r"); zero();      flagbother = 1;    }  }  if (!flagbother) quit("DGiving up on ","");   substdio_putsflush(&smtpto,"DATA\r\n");  code = smtpcode();  if (code >= 500) quit("D"," failed on DATA command");  if (code >= 400) quit("Z"," failed on DATA command");   blast();  code = smtpcode();  flagcritical = 0;  if (code >= 500) quit("D"," failed after I sent the message");  if (code >= 400) quit("Z"," failed after I sent the message");  quit("K"," accepted message");}stralloc canonhost = {0};stralloc canonbox = {0};void addrmangle(saout,s,flagalias,flagcname)stralloc *saout; /* host has to be canonical, box has to be quoted */char *s;int *flagalias;int flagcname;{  int j;   *flagalias = flagcname;   j = str_rchr(s,'@');  if (!s[j]) {    if (!stralloc_copys(saout,s)) temp_nomem();    return;  }  if (!stralloc_copys(&canonbox,s)) temp_nomem();  canonbox.len = j;  if (!quote(saout,&canonbox)) temp_nomem();  if (!stralloc_cats(saout,"@")) temp_nomem();   if (!stralloc_copys(&canonhost,s + j + 1)) temp_nomem();  if (flagcname)    switch(dns_cname(&canonhost)) {      case 0: *flagalias = 0; break;      case DNS_MEM: temp_nomem();      case DNS_SOFT: temp_dnscanon();      case DNS_HARD: ; /* alias loop, not our problem */    }  if (!stralloc_cat(saout,&canonhost)) temp_nomem();}void getcontrols(){  if (control_init() == -1) temp_control();

  //讀入timeoutremote，timeoutremote用來指定qmail-remote在一個SMTP連接已經建立后，
  //遠程郵件主機的每一個回應的時間數。默認值為1200秒。  if (control_readint(&timeout,"control/timeoutremote") == -1) temp_control();  if (control_readint(&timeoutconnect,"control/timeoutconnect") == -1)    temp_control();  if (control_rldef(&helohost,"control/helohost",1,(char *) 0) != 1)    temp_control();

  //讀入smtproutes，smtproutes用來指定到固定目的的靜態SMTP路線
  /*
  例子：smtproutes內容如下 
	rainbow.linuxfane.com:mail8.rainbow.jp 
	:fw.rainbow.linuxfane.com:8088 
	第一行的存在會將發給rainbow.linuxfane.com的郵件重定向到mail8.rainbow.jp主機 
	第二行的存在會將任何不符合之前行條件的郵件重定向到fw.rainbow.linuxfane.com的8088端口，讓 
	郵件安全的穿越防火墻 
	qmmail-remote將按照smtproutes中的行序來進行處理
  */  switch(control_readfile(&routes,"control/smtproutes",0)) {    case -1:      temp_control();    case 0:      if (!constmap_init(&maproutes,"",0,1)) temp_nomem(); break;    case 1:      if (!constmap_init(&maproutes,routes.s,routes.len,1)) temp_nomem(); break;  }}void main(argc,argv)int argc;char **argv;{  static ipalloc ip = {0};  int i;  unsigned long random;  char **recips;  unsigned long prefme;  int flagallaliases;  int flagalias;  char *relayhost;   sig_pipeignore();  if (argc < 4) perm_usage();  if (chdir(auto_qmail) == -1) temp_chdir();  getcontrols();    if (!stralloc_copys(&host,argv[1])) temp_nomem();   relayhost = 0;  for (i = 0;i <= host.len;++i)    if ((i == 0) || (i == host.len) || (host.s[i] == '.'))      if (relayhost = constmap(&maproutes,host.s + i,host.len - i))        break;  if (relayhost && !*relayhost) relayhost = 0;   if (relayhost) {    i = str_chr(relayhost,':');    if (relayhost[i]) {      scan_ulong(relayhost + i + 1,&port);      relayhost[i] = 0;    }    if (!stralloc_copys(&host,relayhost)) temp_nomem();  }  addrmangle(&sender,argv[2],&flagalias,0);   if (!saa_readyplus(&reciplist,0)) temp_nomem();  if (ipme_init() != 1) temp_oserr();   flagallaliases = 1;  recips = argv + 3;  while (*recips) {    if (!saa_readyplus(&reciplist,1)) temp_nomem();    reciplist.sa[reciplist.len] = sauninit;    addrmangle(reciplist.sa + reciplist.len,*recips,&flagalias,!relayhost);    if (!flagalias) flagallaliases = 0;    ++reciplist.len;    ++recips;  }   random = now() + (getpid() << 16);  switch (relayhost ? dns_ip(&ip,&host) : dns_mxip(&ip,&host,random)) {    case DNS_MEM: temp_nomem();    case DNS_SOFT: temp_dns();    case DNS_HARD: perm_dns();    case 1:      if (ip.len <= 0) temp_dns();  }   if (ip.len <= 0) perm_nomx();   prefme = 100000;  for (i = 0;i < ip.len;++i)    if (ipme_is(&ip.ix[i].ip))      if (ip.ix[i].pref < prefme)        prefme = ip.ix[i].pref;   if (relayhost) prefme = 300000;  if (flagallaliases) prefme = 500000;   for (i = 0;i < ip.len;++i)    if (ip.ix[i].pref < prefme)      break;   if (i >= ip.len)    perm_ambigmx();   for (i = 0;i < ip.len;++i) if (ip.ix[i].pref < prefme) {    if (tcpto(&ip.ix[i].ip)) continue;     smtpfd = socket(AF_INET,SOCK_STREAM,0);    if (smtpfd == -1) temp_oserr();     if (timeoutconn(smtpfd,&ip.ix[i].ip,(unsigned int) port,timeoutconnect) == 0) {      tcpto_err(&ip.ix[i].ip,0);      partner = ip.ix[i].ip;      smtp(); /* does not return */    }    tcpto_err(&ip.ix[i].ip,errno == error_timeout);    close(smtpfd);  }    temp_noconn();}