add sqmail-4.2.29asqmail-4.2

1 files changed, 201 insertions, 0 deletions

diff --git a/src/dns.c b/src/dns.c
new file mode 100644
index 0000000..3f1154b
--- /dev/null
+++ b/src/dns.c
@@ -0,0 +1,201 @@
+#include <netdb.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <sys/socket.h>
+#include "ip.h"
+#include "ipalloc.h"
+#include "fmt.h"
+#include "alloc.h"
+#include "str.h"
+#include "stralloc.h"
+#include "dnsresolv.h"
+#include "case.h"
+#include "dns.h"
+#include "buffer.h"
+#include "exit.h"
+
+/**
+ @file dns.c
+ @brief DNS helpers: dns_ipplus, dns_ipalloc, dns_ip (IPv4+IPv6), dns_mxip
+ */
+
+static stralloc glue = {0};
+static stralloc ip = {0};
+
+static int dns_ipplus(ipalloc *ia,stralloc *sa,int pref)
+{
+  struct ip_mx ix;
+  int error = 0;
+  char ip4[4];
+  char ip6[16];
+  int i; 
+
+  /* Case 1: sa is just IPv4 */
+
+  if (ip4_scanbracket(sa->s,ip4)) {
+    if (!stralloc_copys(&glue,sa->s)) return DNS_MEM;
+    if (!stralloc_0(&glue)) return DNS_MEM;
+    if (glue.s[0]) {
+      ix.pref = 0;
+      ix.af = AF_INET;
+      byte_copy(&ix.addr,4,ip4); //  = ip; //cp
+      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
+      return 0;
+    }
+  }
+
+  /* Case 2: sa is just IPv6 */
+
+  if (ip6_scanbracket(sa->s,ip6)) { 
+    if (!stralloc_copys(&glue,sa->s)) return DNS_MEM;
+    if (!stralloc_0(&glue)) return DNS_MEM;
+    if (glue.s[0]) {
+      ix.pref = 0;
+      ix.af = AF_INET6;
+      byte_copy(&ix.addr,16,ip6); //  = ip; //cp
+      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
+      return 0;
+    }
+  }
+
+  /* Case 3: sa is fqdn and looking for IPv6 */
+
+  if (dns_ip6(&ip,sa) > 0) {
+    for (i = 0; i + 16 <= ip.len; i += 16) {
+      if (ip6_isv4mapped(ip.s + i)) continue;
+        ix.af = AF_INET6;
+        ix.pref = pref;
+        byte_copy(&ix.addr,16,ip.s + i); //  = ip; //cp
+        str_copy(ix.mxh,sa->s);          // mx hostname
+        if (!ipalloc_append(ia,&ix)) { error = DNS_MEM; break; }
+        error = 0;
+      }
+  } else
+    error = 1;
+
+  /* Case 4: sa is fqdn and looking for IPv4 */
+
+  if (dns_ip4(&ip,sa) > 0) {
+    for (i = 0; i + 4 <= ip.len; i += 4) {
+      ix.af = AF_INET;
+      ix.pref = pref;
+      byte_copy(&ix.addr,4,ip.s + i); //  = ip; //cp
+      str_copy(ix.mxh,sa->s);         // mx hostname
+      if (!ipalloc_append(ia,&ix)) { error = DNS_MEM; break; }
+      error = 0;
+    }
+  } else
+    error += 2; 
+
+  return error;
+}
+
+int dns_ipalloc(ipalloc *ia,stralloc *sa)
+{
+  if (!ipalloc_readyplus(ia,0)) return DNS_MEM;
+  ia->len = 0;
+
+  return dns_ipplus(ia,sa,0);
+}
+
+/* dns_mxip */
+
+int dns_mxip(ipalloc *ia,stralloc *sa,unsigned long random) {
+  struct mx { stralloc sa; unsigned short p; } *mx;
+  struct ip_mx ix;
+  int nummx;
+  int i;
+  int j = 0;
+  int len;
+  int flagsoft;
+  uint16 pref;
+
+  /* Case 1: sa is just IPv4 or IPv6 */
+
+  if (!ipalloc_readyplus(ia,0)) return DNS_MEM;
+  ia->len = 0;
+
+  if (!stralloc_copys(&glue,sa->s)) return DNS_MEM;
+  if (!stralloc_0(&glue)) return DNS_MEM;
+  if (glue.s[0]) {
+    ix.pref = 0;
+    if (!glue.s[ip4_scan(glue.s,(char *)&ix.addr.ip4)] || \
+        !glue.s[ip4_scanbracket(glue.s,(char *)&ix.addr.ip4)]) {
+      ix.af = AF_INET;
+      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
+      return 0;
+    }
+    if (!glue.s[ip6_scan(glue.s,(char *)&ix.addr.ip6)] || \
+        !glue.s[ip6_scanbracket(glue.s,(char *)&ix.addr.ip6)]) {
+      ix.af = AF_INET6;
+      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
+      return 0;
+    }
+  }
+
+  /* Case 2:  sa is FQDN and do a mx lookup */
+
+  DNS_INIT
+  nummx = 0;
+  len = 0;
+  i = dns_mx(&ip,sa);
+  mx = (struct mx *) alloc(i * sizeof(struct mx));
+  if (!mx) return DNS_MEM;
+
+  if (i) {
+    do {
+      j = str_chr(ip.s + len + 2,'\0');  /* several answers */
+      mx[nummx].sa.s = 0;
+      if (!stralloc_copys(&mx[nummx].sa,ip.s + len + 2)) { /* mxhost name */
+        alloc_free(mx); return DNS_MEM;
+      }
+      ip.s[len + 3] = '\0';
+      uint16_unpack_big(ip.s + len,&pref);
+      mx[nummx].p = pref;
+      len += j + 3;
+      ++nummx;
+    } while (len < ip.len);
+  }
+
+  if (!nummx) return dns_ipalloc(ia,sa); /* e.g., CNAME -> A */
+  flagsoft = 0;
+
+  while (nummx > 0) {
+    unsigned long numsame;
+    i = 0;
+    numsame = 1;
+    for (j = 1; j < nummx; ++j) {
+      if (mx[j].p < mx[i].p) {
+        i = j;
+        numsame = 1;
+      }
+      else if (mx[j].p == mx[i].p) {
+        ++numsame;
+        random = random * 69069 + 1;
+        if ((random / 2) < (2147483647 / numsame)) i = j;
+      }
+    }
+
+    switch (dns_ipplus(ia,&mx[i].sa,mx[i].p)) {
+      case -1: return DNS_MEM;
+      case -2: case -3: flagsoft = -5; break;
+    }
+
+    alloc_free(mx[i].sa.s);
+    mx[i] = mx[--nummx];
+  }
+
+  alloc_free(mx);
+  return flagsoft;
+}
+
+int dns_ip(ipalloc *ia,stralloc *sa)
+{
+
+  if (!ipalloc_readyplus(ia,0)) return DNS_MEM;
+  ia->len = 0;
+
+  return dns_ipplus(ia,sa,0);
+}