Start some new work

1 files changed, 167 insertions, 0 deletions

diff --git a/src/qmail-smtpc/qmailr_tcpto.c b/src/qmail-smtpc/qmailr_tcpto.c
new file mode 100644
index 0000000..fc8841b
--- /dev/null
+++ b/src/qmail-smtpc/qmailr_tcpto.c
@@ -0,0 +1,167 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include <skalibs/uint32.h>
+#include <skalibs/uint64.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/cdb.h>
+#include <skalibs/tai.h>
+#include <skalibs/djbunix.h>
+
+#include <smtpd-starttls-proxy/config.h>
+#include "qmailr.h"
+
+#include <skalibs/posixishard.h>
+
+
+/*
+   tcpto implementation, should be compatible with qmail-tcpto.
+   Assumes the 4 unused bytes at the end of a record are there to
+   accommodate 64-bit time_t. Which we use. But qmail-tcpto does
+   not, so you should patch that before 2038.
+   Has ipv6 support, storing v6 records in a different file.
+   Unlike qmail's tcpto, we assume the records are sorted by IP.
+   This makes it easy to look for a record with bsearch. We
+   keep records sorted with every modification, and we aggressively
+   cut empty ones from the file.
+   For the match function, not sure what is faster between mmapping and
+   simple reading. Currently we mmap to save private/dirty RAM, but
+   that holds the lock longer; it should be ok because we switched to
+   a shared lock for this (unsure why djb didn't).
+*/
+
+static int memcmp4 (void const *a, void const *b)
+{
+  return memcmp(a, b, 4) ;
+}
+
+static int memcmp16 (void const *a, void const *b)
+{
+  return memcmp(a, b, 16) ;
+}
+
+int qmailr_tcpto_match (char const *ip, int is6)
+{
+  char const *file = is6 ? SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/tcpto6" : SMTPD_STARTTLS_PROXY_QMAIL_HOME "/queue/lock/tcpto" ;
+  uint32_t iplen = is6 ? 16 : 4 ;
+  uint32_t width = iplen + 12 ;
+  int r = 0 ;
+  char const *p ;
+  cdb c ;  /* XXX: not a cdb, we're just using the mmap wrapper */
+  int fd = openc_read(file) ;
+
+  if (fd == -1) return -1 ;
+  if (fd_lock(fd, 0, 0) == -1) goto err ;
+  if (!cdb_init_fromfd(&c, fd)) goto err ;
+  if (c.size % width) goto errproto ;
+  p = bsearch(ip, c.map, c.size / width, width, is6 ? &memcmp16 : &memcmp4) ;
+  if (p)
+  {
+    if (p[iplen] >= 2)
+    {
+      tai when ;
+      uint64_t x ;
+      uint64_unpack(p + iplen + 4, &x) ;
+      tai_u64(&when, x) ;
+      tai_sub(&when, tain_secp(&STAMP), &when) ;
+      r = tai_sec(&when) < ((60 + (getpid() & 31)) << 6) ;  /* don't ask me, ask djb */
+    }
+  }
+  cdb_free(&c) ;
+  fd_close(fd) ;
+  return r ;
+
+ errproto:
+  errno = EPROTO ;
+ err:
+  fd_close(fd) ;
+  return -1 ;
+}
+
+int qmailr_tcpto_update (char const *ip, int is6, int problem)
+{
+  char const *file = is6 ? SMTPD_STARTTLS_PROXY_QMAIL_HOME "/run/qmail-remote/tcpto6" : SMTPD_STARTTLS_PROXY_QMAIL_HOME "/queue/lock/tcpto" ;
+  uint32_t iplen = is6 ? 16 : 4 ;
+  uint32_t width = iplen + 12 ;
+  uint32_t n ;
+  char *p = 0 ;
+  struct stat st ;
+  int fdr ;
+  int fdw = openc_create(file) ;
+
+  if (fdw == -1) return 0 ;
+  if (fd_lock(fdw, 1, 0) == -1) goto err ;
+  fdr = openc_read(file) ;
+  if (fdr == -1) goto err ;
+  if (fstat(fdr, &st) == -1) goto err0 ;
+  if (st.st_size % width) goto errproto ;
+  n = st.st_size / width ;
+
+  {
+    char buf[(n+1) * width] ;  /* relax, it won't bite */
+    if (n)
+    {
+      if (allread(fdr, buf, st.st_size) < st.st_size) goto err0 ;
+      memset(buf + st.st_size, 0, width) ;
+      p = bsearch(ip, buf, n, width, is6 ? &memcmp16 : &memcmp4) ;
+      if (p)
+      {
+        if (problem)
+        {
+          tai when ;
+          uint64_t x ;
+          uint64_unpack(p + iplen + 4, &x) ;
+          tai_u64(&when, x) ;
+          tai_sub(&when, tain_secp(&STAMP), &when) ;
+          if (tai_sec(&when) < 120) p = 0 ;
+          else
+          {
+            if (++p[iplen] > 10) p[iplen] = 10 ;
+            x = tai_sec(tain_secp(&STAMP)) - TAI_MAGIC ;
+            uint64_pack(p + iplen + 4, x) ;
+          }
+        }
+        else p[iplen] = 0 ;
+      }
+    }
+    else if (problem)
+    {
+      uint64_t x = tai_sec(tain_secp(&STAMP)) - TAI_MAGIC ;
+      p = buf + n++ * width ;
+      memcpy(p, ip, iplen) ;
+      p[iplen] = 1 ;
+      memset(p + iplen + 1, 0, 3) ;
+      uint64_pack(p + iplen + 4, x) ;
+    }
+    fd_close(fdr) ;
+
+    if (p)
+    {
+      for (uint32_t i = 0 ; i < n ; i++)
+        if (!buf[i * width + iplen])
+          memcpy(buf + i * width, buf + --n * width, width) ;
+      if (n)
+      {
+        qsort(buf, n, width, is6 ? &memcmp16 : &memcmp4) ;
+        if (allwrite(fdw, buf, n * width) < n * width) goto err ;
+      }
+      if (ftruncate(fdw, n * width) == -1) goto err ;
+    }
+  }
+
+  fd_close(fdw) ;
+  return 1 ;
+
+ errproto:
+  errno = EPROTO ;
+ err0:
+  fd_close(fdr) ;
+ err:
+  fd_close(fdw) ;
+  return 0 ;
+}