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qmail/qmail-remote.c
D. J. Bernstein d15ee51c9d qmail 1.02
2016-01-17 17:37:05 +01:00

427 lines
11 KiB
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#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};
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();
}
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();
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();
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();
}
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