DTLS: Introduce custom I/O callbacks API and structure

Author: julek-wolfssl

src/wolfio.c

@@ -638,6 +638,18 @@ static int isDGramSock(int sfd)
     }
 }
 
+void wolfSSL_SetRecvFrom(WOLFSSL* ssl, WolfSSLRecvFrom recvFrom)
+{
+    if (ssl != NULL)
+        ssl->buffers.dtlsCtx.recvfrom = recvFrom;
+}
+
+void wolfSSL_SetSendTo(WOLFSSL* ssl, WolfSSLSento sendTo)
+{
+    if (ssl != NULL)
+        ssl->buffers.dtlsCtx.sendto = sendTo;
+}
+
 /* The receive embedded callback
  *  return : nb bytes read, or error
  */
@@ -686,10 +698,6 @@ int EmbedReceiveFrom(WOLFSSL *ssl, char *buf, int sz, void *ctx)
         /* Store the peer address. It is used to calculate the DTLS cookie. */
         newPeer = dtlsCtx->peer.sa == NULL || !ssl->options.dtlsStateful;
         peer = &lclPeer;
-        if (dtlsCtx->peer.sa != NULL) {
-            XMEMCPY(peer, (SOCKADDR_S*)dtlsCtx->peer.sa, MIN(sizeof(lclPeer),
-                    dtlsCtx->peer.sz));
-        }
         peerSz = sizeof(lclPeer);
     }
 
@@ -785,8 +793,16 @@ int EmbedReceiveFrom(WOLFSSL *ssl, char *buf, int sz, void *ctx)
 
         {
             XSOCKLENT inPeerSz = peerSz;
-            recvd = (int)DTLS_RECVFROM_FUNCTION(sd, buf, (size_t)sz,
-                 ssl->rflags, (SOCKADDR*)peer, peer != NULL ? &inPeerSz : NULL);
+            if (dtlsCtx->recvfrom == NULL) {
+                recvd = (int)DTLS_RECVFROM_FUNCTION(sd, buf, (size_t)sz,
+                        ssl->rflags, (SOCKADDR*)peer,
+                        peer != NULL ? &inPeerSz : NULL);
+            }
+            else {
+                recvd = (int)dtlsCtx->recvfrom(sd, buf, (size_t) sz,
+                        ssl->rflags, (SOCKADDR*) peer,
+                        peer != NULL ? &inPeerSz : NULL);
+            }
             /* Truncate peerSz. From the RECV(2) man page
              * The returned address is truncated if the buffer provided is too
              * small; in this case, addrlen will return a value greater than was
@@ -914,8 +930,14 @@ int EmbedSendTo(WOLFSSL* ssl, char *buf, int sz, void *ctx)
 #endif
     }
 
-    sent = (int)DTLS_SENDTO_FUNCTION(sd, buf, (size_t)sz, ssl->wflags,
-            (const SOCKADDR*)peer, peerSz);
+    if (dtlsCtx->sendto == NULL) {
+        sent = (int)DTLS_SENDTO_FUNCTION(sd, buf, (size_t)sz, ssl->wflags,
+                (const SOCKADDR*)peer, peerSz);
+    }
+    else {
+        sent = (int)dtlsCtx->sendto(sd, buf, (size_t)sz, ssl->wflags,
+                (const SOCKADDR*)peer, peerSz);
+    }
 
     sent = TranslateIoReturnCode(sent, sd, SOCKET_SENDING);
 

wolfssl/internal.h

@@ -26,6 +26,7 @@
 
 #include <wolfssl/wolfcrypt/types.h>
 #include <wolfssl/ssl.h>
+#include <wolfssl/wolfio.h>
 #ifdef HAVE_CRL
     #include <wolfssl/crl.h>
 #endif
@@ -2730,6 +2731,7 @@ struct WOLFSSL_SOCKADDR {
     void*        sa; /* pointer to the sockaddr_in or sockaddr_in6 */
 };
 
+#ifdef WOLFSSL_DTLS
 typedef struct WOLFSSL_DTLS_CTX {
 #ifdef WOLFSSL_RW_THREADED
     /* Protect peer access after the handshake */
@@ -2743,6 +2745,8 @@ typedef struct WOLFSSL_DTLS_CTX {
 #endif
     int rfd;
     int wfd;
+    WolfSSLRecvFrom recvfrom;
+    WolfSSLSento sendto;
     byte userSet:1;
     byte connected:1; /* When set indicates rfd and wfd sockets are
                        * connected (connect() and bind() both called).
@@ -2752,6 +2756,7 @@ typedef struct WOLFSSL_DTLS_CTX {
     byte processingPendingRecord:1;
 #endif
 } WOLFSSL_DTLS_CTX;
+#endif
 
 
 typedef struct WOLFSSL_DTLS_PEERSEQ {

wolfssl/wolfio.h

@@ -624,6 +624,15 @@ WOLFSSL_LOCAL int BioReceiveInternal(WOLFSSL_BIO* biord, WOLFSSL_BIO* biowr,
                                      char* buf, int sz);
 #endif
 WOLFSSL_LOCAL int SslBioReceive(WOLFSSL* ssl, char* buf, int sz, void* ctx);
+
+#ifdef WOLFSSL_DTLS
+    typedef ssize_t (*WolfSSLRecvFrom)(int sockfd, void* buf, size_t len, int flags,
+                            void* src_addr, void* addrlen);
+    typedef ssize_t (*WolfSSLSento)(int sockfd, const void* buf, size_t len, int flags,
+                          const void* dest_addr, word32 addrlen);
+    WOLFSSL_API void wolfSSL_SetRecvFrom(WOLFSSL* ssl, WolfSSLRecvFrom recvFrom);
+    WOLFSSL_API void wolfSSL_SetSendTo(WOLFSSL* ssl, WolfSSLSento sendTo);
+#endif
 #if defined(USE_WOLFSSL_IO)
     /* default IO callbacks */