Use BSD's message-digest library (-lmd) instead of UDT's own
MD5-implementation.

Original proposed to use OpenSSL for portability, but rejected by
the author anyway out of concern for Windows computers and mobile
devices:

	https://sourceforge.net/p/udt/patches/5/

This new version also allows to pass the length of the input and
modifies the only two callers (both in core.cpp) to do that -- to
avoid a strlen().

	-mi

--- src/common.h	2013-02-20 11:35:26.000000000 -0500
+++ src/common.h	2013-02-26 13:53:52.000000000 -0500
@@ -315,4 +315,5 @@
 {
    static void compute(const char* input, unsigned char result[16]);
+   static void compute(const char* input, size_t ilen, unsigned char result[16]);
 };
 
--- src/common.cpp	2013-02-20 11:35:26.000000000 -0500
+++ src/common.cpp	2013-02-26 13:56:57.000000000 -0500
@@ -56,5 +56,5 @@
 
 #include <cmath>
-#include "md5.h"
+#include <md5.h>
 #include "common.h"
 
@@ -756,10 +756,15 @@
 
 //
-void CMD5::compute(const char* input, unsigned char result[16])
+void CMD5::compute(const char* input, size_t ilen, unsigned char result[16])
 {
-   md5_state_t state;
+   MD5_CTX	state;
+
+   MD5Init(&state);
+   MD5Update(&state, (const void *)input, ilen);
+   MD5Final(result, &state);
+}
 
-   md5_init(&state);
-   md5_append(&state, (const md5_byte_t *)input, strlen(input));
-   md5_finish(&state, result);
+void CMD5::compute(const char* input, unsigned char result[16])
+{
+   compute(input, strlen(input), result);
 }
--- src/core.cpp	2013-02-20 11:35:26.000000000 -0500
+++ src/core.cpp	2013-02-26 18:49:00.000000000 -0500
@@ -40,4 +40,6 @@
 
 #ifndef WIN32
+   #include <err.h>
+   #include <stdint.h>
    #include <unistd.h>
    #include <netdb.h>
@@ -2460,12 +2461,28 @@
 
    // SYN cookie
-   char clienthost[NI_MAXHOST];
-   char clientport[NI_MAXSERV];
-   getnameinfo(addr, (AF_INET == m_iVersion) ? sizeof(sockaddr_in) : sizeof(sockaddr_in6), clienthost, sizeof(clienthost), clientport, sizeof(clientport), NI_NUMERICHOST|NI_NUMERICSERV);
+   char clientport[6]; /* Longest decimal representation of a short number */
+   char cookiestr[(AF_INET == addr->sa_family ? INET_ADDRSTRLEN : INET6_ADDRSTRLEN) +
+      sizeof(clientport) + 64];
+   int gaie = getnameinfo(addr, addr->sa_len, cookiestr, INET6_ADDRSTRLEN,
+      clientport, sizeof(clientport), NI_NUMERICHOST|NI_NUMERICSERV);
+   if (gaie) {
+#ifndef WIN32
+	warnx("getnameinfo: %s (addr->sa_family: %d -- %sAF_INET, family: %d, length: %u, "
+	    "size: %zd of %zd and %zd)",
+	    gai_strerror(gaie), addr->sa_family, addr->sa_family == AF_INET ? "" : "not ",
+	    addr->sa_family, (unsigned int)addr->sa_len,
+	    AF_INET == addr->sa_family ? sizeof(sockaddr_in) : sizeof(sockaddr_in6),
+	    sizeof(sockaddr_in), sizeof(sockaddr_in6));
+#endif
+	return -1;
+   }
    int64_t timestamp = (CTimer::getTime() - m_StartTime) / 60000000; // secret changes every one minute
-   stringstream cookiestr;
-   cookiestr << clienthost << ":" << clientport << ":" << timestamp;
+   size_t cookielen, saltedlen;
+
+   cookielen = strlen(cookiestr);
+   cookielen += sprintf(cookiestr + cookielen, ":%s:", clientport);
+   saltedlen = cookielen + sprintf(cookiestr + cookielen, "%jd", (intmax_t)timestamp);
    unsigned char cookie[16];
-   CMD5::compute(cookiestr.str().c_str(), cookie);
+   CMD5::compute(cookiestr, saltedlen, cookie);
 
    if (1 == hs.m_iReqType)
@@ -2483,6 +2500,6 @@
       {
          timestamp --;
-         cookiestr << clienthost << ":" << clientport << ":" << timestamp;
-         CMD5::compute(cookiestr.str().c_str(), cookie);
+         saltedlen = cookielen + sprintf(cookiestr + cookielen, "%jd", (intmax_t)timestamp);
+         CMD5::compute(cookiestr, saltedlen, cookie);
 
          if (hs.m_iCookie != *(int*)cookie)