Don't require OpenSSL 3

Author: mickel8

bundlex.exs

@@ -15,7 +15,7 @@ defmodule ExDTLS.BundlexProject do
         os_deps: [openssl: :pkg_config],
         libs: ["pthread"],
         interface: [:nif],
-        compiler_flags: ["-DEXDTLS_DEBUG"],
+        # compiler_flags: ["-DEXDTLS_DEBUG"],
         preprocessor: Unifex
       ]
     ]

c_src/ex_dtls/bio_frag.c

@@ -1,5 +1,6 @@
 
 #include "bio_frag.h"
+#include <openssl/bio.h>
 
 static int bwrite(BIO *bio, const char *buf, int len);
 static int bread(BIO *bio, char *buf, int len);
@@ -8,23 +9,16 @@ static int create(BIO *bio);
 static int destroy(BIO *bio);
 static long callback_ctrl(BIO *bio, int cmd, BIO_info_cb *fp);
 
-// static const BIO_METHOD bio_methods = {
-//   BIO_TYPE_BIO,
-//   "DTLS fragmentation for mem BIO",
-//   bwrite_conv,
-//   bwrite,
-//   bread_conv,
-//   bread,
-//   NULL,
-//   NULL,
-//   ctrl,
-//   create,
-//   destroy,
-//   callback_ctrl
-// };
-
 static BIO_METHOD *bio_methods = NULL;
 
+#define MAX_FRAGS 100
+
+struct Ctx {
+  int frag_sizes[MAX_FRAGS];
+  int witer;
+  int riter;
+};
+
 const BIO_METHOD *BIO_f_frag(void) {
   bio_methods = BIO_meth_new(BIO_TYPE_FILTER, "DTLS fragmentation for mem BIO");
 
@@ -39,50 +33,99 @@ const BIO_METHOD *BIO_f_frag(void) {
 }
 
 static int create(BIO *bio) {
-  DEBUG("BIO frag create");
-  // indicate that BIO initialization is complete 
+  struct Ctx *ctx = calloc(1, sizeof(struct Ctx));
+  for (int i = 0; i < MAX_FRAGS; i++) {
+    ctx->frag_sizes[i] = 0;
+  }
+  ctx->witer = 0;
+  ctx->riter = 0;
+
+  BIO_set_data(bio, ctx);
   BIO_set_init(bio, 1);
   return 1;
 }
 
 static int destroy(BIO *bio) {
-  DEBUG("BIO frag destroy");
   if (bio == NULL) {
     return 0;
   }
 
+  struct Ctx *ctx = BIO_get_data(bio);
+  free(ctx);
+  BIO_set_data(bio, NULL);
   BIO_set_init(bio, 0);
   return 1;
 }
 
 static int bread(BIO *bio, char *buf, int len) {
-  DEBUG("BIO frag bread");
   BIO *next = BIO_next(bio);
   if (next == NULL) {
     return 0;
   }
 
-  return BIO_read(next, buf, len);
+  struct Ctx *ctx = BIO_get_data(bio);
+
+  if (len != ctx->frag_sizes[ctx->riter]) {
+    return 0;
+  }
+
+  int ret = BIO_read(next, buf, len);
+
+  if (ret > 0) {
+    if (ret == ctx->frag_sizes[ctx->riter]) {
+      ctx->frag_sizes[ctx->riter] = 0;
+      ctx->riter++;
+
+      if (ctx->riter == ctx->witer && ctx->frag_sizes[ctx->riter] == 0) {
+        // reset iterators
+        ctx->riter = 0;
+        ctx->witer = 0;
+      }
+
+    } else if (ret < ctx->frag_sizes[ctx->riter]) {
+      ctx->frag_sizes[ctx->riter] -= ret;
+    } else {
+      // This should never happen
+      return 0;
+    }
+  };
+
+  return ret;
 }
 
 static int bwrite(BIO *bio, const char *buf, int len) {
-  DEBUG("BIO frag bwrite %d", len);
   BIO *next = BIO_next(bio);
   if (next == NULL) {
     return 0;
   }
 
-  return BIO_write(next, buf, len);
+  struct Ctx *ctx = BIO_get_data(bio);
+
+  if (ctx->witer >= MAX_FRAGS) {
+    return 0;
+  }
+
+  int ret = BIO_write(next, buf, len);
+  if (ret > 0) {
+    ctx->frag_sizes[ctx->witer] = ret;
+    ctx->witer++;
+  }
+
+  return ret;
 }
 
 static long ctrl(BIO *bio, int cmd, long num, void *ptr) {
-  DEBUG("BIO frag ctrl");
-
   BIO *next = BIO_next(bio);
   if (next == NULL) {
     return 0;
   }
 
+  struct Ctx *ctx = BIO_get_data(bio);
+
+  if (cmd == BIO_CTRL_PENDING) {
+    return ctx->frag_sizes[ctx->riter];
+  }
+
   return BIO_ctrl(next, cmd, num, ptr);
 }
 
@@ -94,5 +137,3 @@ static long callback_ctrl(BIO *bio, int cmd, BIO_info_cb *fp) {
 
   return BIO_callback_ctrl(next, cmd, fp);
 }
-
-

c_src/ex_dtls/dtls.c

@@ -35,46 +35,42 @@ SSL *create_ssl(SSL_CTX *ssl_ctx, int mode) {
     return NULL;
   }
 
-  // BIO *frag_bio = BIO_new(BIO_f_frag());
-  // if (frag_bio == NULL) {
-  //   DEBUG("Cannot create frag bio");
-  //   return NULL;
-  // }
+  BIO *frag_bio = BIO_new(BIO_f_frag());
+  if (frag_bio == NULL) {
+    DEBUG("Cannot create frag bio");
+    return NULL;
+  }
 
-  // BIO *wmem_bio = BIO_new(BIO_s_mem());
-  // if (wmem_bio == NULL) {
-  //   DEBUG("Cannot create write mem bio");
-  //   return NULL;
-  // }
+  BIO *wmem_bio = BIO_new(BIO_s_mem());
+  if (wmem_bio == NULL) {
+    DEBUG("Cannot create write mem bio");
+    return NULL;
+  }
 
-  // BIO *wchain = BIO_push(frag_bio, wmem_bio);
+  BIO *wchain = BIO_push(frag_bio, wmem_bio);
 
   BIO *rmem_bio = BIO_new(BIO_s_mem());
   if (rmem_bio == NULL) {
     DEBUG("Cannot create read mem bio");
     return NULL;
   }
 
-  BIO *rbio = BIO_new(BIO_s_dgram_mem());
-  if (rbio == NULL) {
-    DEBUG("Cannot create read dgram mem bio");
-    return NULL;
-  }
-
-  BIO *wbio = BIO_new(BIO_s_dgram_mem());
-  if (wbio == NULL) {
-    DEBUG("Cannot create write dgram mem bio");
-    return NULL;
-  }
+  // #TODO Move to the BIO_s_dgram_mem once we require OpenSSL 3
+  // BIO *rbio = BIO_new(BIO_s_dgram_mem());
+  // if (rbio == NULL) {
+  //   DEBUG("Cannot create read dgram mem bio");
+  //   return NULL;
+  // }
 
-  // SSL_set_bio(ssl, rmem_bio, wchain);
-  SSL_set_bio(ssl, rbio, wbio);
-  
-  // printf("Setting MTU to 1000\n");
-  // if (SSL_set_mtu(ssl, 1500) == 0) {
+  // BIO *wbio = BIO_new(BIO_s_dgram_mem());
+  // if (wbio == NULL) {
+  //   DEBUG("Cannot create write dgram mem bio");
   //   return NULL;
-  // } 
-  
+  // }
+
+  SSL_set_bio(ssl, rmem_bio, wchain);
+  // SSL_set_bio(ssl, rbio, wbio);
+
   return ssl;
 }
 

c_src/ex_dtls/native.c

@@ -34,11 +34,6 @@ int handle_load(UnifexEnv *env, void **priv_data) {
   UNIFEX_UNUSED(env);
   UNIFEX_UNUSED(priv_data);
 
-  if (OPENSSL_VERSION_NUMBER < 0x30000000L) {
-    DEBUG("ExDTLS requires OpenSSL 3");
-    return -1;
-  }
-
   FILE *urandom = fopen("/dev/urandom", "r");
   if (urandom == NULL) {
     DEBUG("Cannot open /dev/urandom");