1 files changed, 80 insertions, 0 deletions
diff --git a/src/src/host_address.c b/src/src/host_address.c
new file mode 100644
index 000000000..9e6f958be
--- /dev/null
+++ b/src/src/host_address.c
@@ -0,0 +1,80 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2020 - 2022 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#include "exim.h"
+
+/*************************************************
+*        Extract port from address string        *
+*************************************************/
+
+/* In the spool file, and in the -oMa and -oMi options, a host plus port is
+given as an IP address followed by a dot and a port number. This function
+decodes this.
+
+An alternative format for the -oMa and -oMi options is [ip address]:port which
+is what Exim 4 uses for output, because it seems to becoming commonly used,
+whereas the dot form confuses some programs/people. So we recognize that form
+too.
+
+Argument:
+  address    points to the string; if there is a port, the '.' in the string
+             is overwritten with zero to terminate the address; if the string
+             is in the [xxx]:ppp format, the address is shifted left and the
+             brackets are removed
+
+Returns:     0 if there is no port, else the port number. If there's a syntax
+             error, leave the incoming address alone, and return 0.
+*/
+
+int
+host_address_extract_port(uschar * address)
+{
+int port = 0;
+uschar *endptr;
+
+/* Handle the "bracketed with colon on the end" format */
+
+if (*address == '[')
+  {
+  uschar *rb = address + 1;
+  while (*rb != 0 && *rb != ']') rb++;
+  if (*rb++ == 0) return 0;        /* Missing ]; leave invalid address */
+  if (*rb == ':')
+    {
+    port = Ustrtol(rb + 1, &endptr, 10);
+    if (*endptr != 0) return 0;    /* Invalid port; leave invalid address */
+    }
+  else if (*rb != 0) return 0;     /* Bad syntax; leave invalid address */
+  memmove(address, address + 1, rb - address - 2);
+  rb[-2] = 0;
+  }
+
+/* Handle the "dot on the end" format */
+
+else
+  {
+  int skip = -3;                   /* Skip 3 dots in IPv4 addresses */
+  address--;
+  while (*(++address) != 0)
+    {
+    int ch = *address;
+    if (ch == ':') skip = 0;       /* Skip 0 dots in IPv6 addresses */
+      else if (ch == '.' && skip++ >= 0) break;
+    }
+  if (*address == 0) return 0;
+  port = Ustrtol(address + 1, &endptr, 10);
+  if (*endptr != 0) return 0;      /* Invalid port; leave invalid address */
+  *address = 0;
+  }
+
+return port;
+}
+
+/* vi: aw ai sw=2
+*/
+/* End of host.c */