Experimentl websocket support

examples/Makefile

@@ -6,4 +6,5 @@ all:
 	  $(CC) $(CFLAGS) hello.c ../mongoose.c  $$LIBS $(ADD) -o hello;
 	  $(CC) $(CFLAGS) upload.c ../mongoose.c  $$LIBS $(ADD) -o upload;
 	  $(CC) $(CFLAGS) post.c ../mongoose.c  $$LIBS $(ADD) -o post;
+	  $(CC) $(CFLAGS) -DUSE_WEBSOCKET websocket.c ../mongoose.c  $$LIBS $(ADD) -o websocket;
 	  $(CC) $(CFLAGS) chat.c ../mongoose.c  $$LIBS $(ADD) -o chat

mongoose.c

@@ -3494,6 +3494,243 @@ static void handle_propfind(struct mg_connection *conn, const char* path,
   conn->num_bytes_sent += mg_printf(conn, "%s\n", "</d:multistatus>");
 }
 
+#if defined(USE_WEBSOCKET)
+
+// START OF SHA-1 code
+// Copyright(c) By Steve Reid <steve@edmweb.com>
+#define SHA1HANDSOFF
+#if defined(__sun)
+#include "solarisfixes.h"
+#endif
+#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
+    |(rol(block->l[i],8)&0x00FF00FF))
+#elif BYTE_ORDER == BIG_ENDIAN
+#define blk0(i) block->l[i]
+#else
+#error "Endianness not defined!"
+#endif
+#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
+    ^block->l[(i+2)&15]^block->l[i&15],1))
+#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
+#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
+#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
+#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
+#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
+
+typedef struct {
+    uint32_t state[5];
+    uint32_t count[2];
+    unsigned char buffer[64];
+} SHA1_CTX;
+
+static void SHA1Transform(uint32_t state[5], const unsigned char buffer[64]) {
+  uint32_t a, b, c, d, e;
+  typedef union { unsigned char c[64]; uint32_t l[16]; } CHAR64LONG16;
+
+  CHAR64LONG16 block[1];
+  memcpy(block, buffer, 64);
+  a = state[0];
+  b = state[1];
+  c = state[2];
+  d = state[3];
+  e = state[4];
+  R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
+  R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
+  R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
+  R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
+  R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
+  R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
+  R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
+  R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
+  R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
+  R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
+  R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
+  R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
+  R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
+  R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
+  R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
+  R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
+  R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
+  R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
+  R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
+  R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
+  state[0] += a;
+  state[1] += b;
+  state[2] += c;
+  state[3] += d;
+  state[4] += e;
+  a = b = c = d = e = 0;
+  memset(block, '\0', sizeof(block));
+}
+
+static void SHA1Init(SHA1_CTX* context) {
+  context->state[0] = 0x67452301;
+  context->state[1] = 0xEFCDAB89;
+  context->state[2] = 0x98BADCFE;
+  context->state[3] = 0x10325476;
+  context->state[4] = 0xC3D2E1F0;
+  context->count[0] = context->count[1] = 0;
+}
+
+static void SHA1Update(SHA1_CTX* context, const unsigned char* data,
+                       uint32_t len) {
+  uint32_t i, j;
+
+  j = context->count[0];
+  if ((context->count[0] += len << 3) < j)
+    context->count[1]++;
+  context->count[1] += (len>>29);
+  j = (j >> 3) & 63;
+  if ((j + len) > 63) {
+    memcpy(&context->buffer[j], data, (i = 64-j));
+    SHA1Transform(context->state, context->buffer);
+    for ( ; i + 63 < len; i += 64) {
+      SHA1Transform(context->state, &data[i]);
+    }
+    j = 0;
+  }
+  else i = 0;
+  memcpy(&context->buffer[j], &data[i], len - i);
+}
+
+static void SHA1Final(unsigned char digest[20], SHA1_CTX* context) {
+  unsigned i;
+  unsigned char finalcount[8], c;
+
+  for (i = 0; i < 8; i++) {
+    finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
+                                     >> ((3-(i & 3)) * 8) ) & 255);
+  }
+  c = 0200;
+  SHA1Update(context, &c, 1);
+  while ((context->count[0] & 504) != 448) {
+    c = 0000;
+    SHA1Update(context, &c, 1);
+  }
+  SHA1Update(context, finalcount, 8);
+  for (i = 0; i < 20; i++) {
+    digest[i] = (unsigned char)
+      ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
+  }
+  memset(context, '\0', sizeof(*context));
+  memset(&finalcount, '\0', sizeof(finalcount));
+}
+// END OF SHA1 CODE
+
+static void base64_encode(const unsigned char *src, int src_len, char *dst) {
+  static const char *b64 =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+  int i, j, a, b, c;
+
+  for (i = j = 0; i < src_len; i += 3) {
+    a = src[i];
+    b = i + 1 >= src_len ? 0 : src[i + 1];
+    c = i + 2 >= src_len ? 0 : src[i + 2];
+
+    dst[j++] = b64[a >> 2];
+    dst[j++] = b64[((a & 3) << 4) | (b >> 4)];
+    if (i + 1 < src_len) {
+      dst[j++] = b64[(b & 15) << 2 | (c >> 6)];
+    }
+    if (i + 2 < src_len) {
+      dst[j++] = b64[c & 63];
+    }
+  }
+  while (j % 4 != 0) {
+    dst[j++] = '=';
+  }
+  dst[j++] = '\0';
+}
+
+static void send_websocket_handshake(struct mg_connection *conn) {
+  static const char *magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+  char buf[100], sha[20], b64_sha[sizeof(sha) * 2];
+  SHA1_CTX sha_ctx;
+
+  mg_snprintf(conn, buf, sizeof(buf), "%s%s",
+              mg_get_header(conn, "Sec-WebSocket-Key"), magic);
+  SHA1Init(&sha_ctx);
+  SHA1Update(&sha_ctx, (unsigned char *) buf, strlen(buf));
+  SHA1Final((unsigned char *) sha, &sha_ctx);
+  base64_encode((unsigned char *) sha, sizeof(sha), b64_sha);
+  mg_printf(conn, "%s%s%s",
+            "HTTP/1.1 101 Switching Protocols\r\n"
+            "Upgrade: websocket\r\n"
+            "Connection: Upgrade\r\n"
+            "Sec-WebSocket-Accept: ", b64_sha, "\r\n\r\n");
+}
+
+static void read_websocket(struct mg_connection *conn) {
+  unsigned char *mask, *buf = (unsigned char *) conn->body;
+  int n, len, mask_len, body_len;
+
+  for (;;) {
+    if ((body_len = conn->data_len - conn->request_len) >= 2) {
+      len = buf[1] & 127;
+      mask_len = buf[1] & 128 ? 4 : 0;
+      if (len < 126) {
+        conn->content_len = 2 + mask_len + len;
+        mask = buf + 2;
+      } else if (len == 126 && body_len >= 4) {
+        conn->content_len = 2 + mask_len + ((((int) buf[2]) << 8) + buf[3]);
+        mask = buf + 4;
+      } else if (body_len >= 10) {
+        conn->content_len = 2 + mask_len +
+          ((uint64_t) htonl(* (uint32_t *) &buf[2])) << 32 |
+          htonl(* (uint32_t *) &buf[6]);
+        mask = buf + 10;
+      }
+    }
+
+    if (conn->content_len > 0) {
+      conn->next_request = conn->buf + conn->data_len;
+      if (call_user(conn, MG_WEBSOCKET_MESSAGE) != NULL) {
+        break;  // Callback signalled to exit
+      }
+    } else {
+      if (wait_until_socket_is_readable(conn) == 0) {
+        break;
+      }
+      n = pull(NULL, conn, conn->buf + conn->data_len,
+               conn->buf_size - conn->data_len);
+      if (n <= 0) {
+        break;
+      }
+      conn->data_len += n;
+    }
+  }
+}
+
+static void handle_websocket_request(struct mg_connection *conn) {
+  if (strcmp(mg_get_header(conn, "Sec-WebSocket-Version"), "13") != 0) {
+    send_http_error(conn, 426, "Upgrade Required", "%s", "Upgrade Required");
+  } else if (call_user(conn, MG_WEBSOCKET_CONNECT) != NULL) {
+    // Callback has returned non-NULL, do not proceed with handshake
+  } else {
+    send_websocket_handshake(conn);
+    call_user(conn, MG_WEBSOCKET_READY);
+    read_websocket(conn);
+  }
+}
+
+static int is_websocket_request(const struct mg_connection *conn) {
+  const char *host, *upgrade, *connection, *version, *key;
+
+  host = mg_get_header(conn, "Host");
+  upgrade = mg_get_header(conn, "Upgrade");
+  connection = mg_get_header(conn, "Connection");
+  key = mg_get_header(conn, "Sec-WebSocket-Key");
+  version = mg_get_header(conn, "Sec-WebSocket-Version");
+
+  return host != NULL && upgrade != NULL && connection != NULL &&
+    key != NULL && version != NULL &&
+    !mg_strcasecmp(upgrade, "websocket") &&
+    !mg_strcasecmp(connection, "Upgrade");
+}
+#endif // !USE_WEBSOCKET
+
 // This is the heart of the Mongoose's logic.
 // This function is called when the request is read, parsed and validated,
 // and Mongoose must decide what action to take: serve a file, or
@@ -3515,6 +3752,10 @@ static void handle_request(struct mg_connection *conn) {
   DEBUG_TRACE(("%s", ri->uri));
   if (!check_authorization(conn, path)) {
     send_authorization_request(conn);
+#if defined(USE_WEBSOCKET)
+  } else if (is_websocket_request(conn)) {
+    handle_websocket_request(conn);
+#endif
   } else if (call_user(conn, MG_NEW_REQUEST) != NULL) {
     // Do nothing, callback has served the request
   } else if (!strcmp(ri->request_method, "OPTIONS")) {

mongoose.h

@@ -49,16 +49,23 @@ struct mg_request_info {
   } http_headers[64];    // Maximum 64 headers
 };
 
+
 // Various events on which user-defined function is called by Mongoose.
 enum mg_event {
   MG_NEW_REQUEST,       // New HTTP request has arrived from the client
   MG_REQUEST_COMPLETE,  // Mongoose has finished handling the request
   MG_HTTP_ERROR,        // HTTP error must be returned to the client
   MG_EVENT_LOG,         // Mongoose logs an event, request_info.log_message
-  MG_INIT_SSL           // Mongoose initializes SSL. Instead of mg_connection *,
-                        // SSL context is passed to the callback function.
+  MG_INIT_SSL,          // SSL initialization, sent before certificate setup
+  MG_WEBSOCKET_CONNECT, // Sent on HTTP connect, before websocket handshake.
+                        // If user callback returns NULL, then mongoose proceeds
+                        // with handshake, otherwise it closes the connection.
+  MG_WEBSOCKET_READY,   // Handshake has been successfully completed.
+  MG_WEBSOCKET_MESSAGE, // Incoming message from the client
+  MG_WEBSOCKET_CLOSE,   // Client has sent FIN frame
 };
 
+
 // Prototype for the user-defined function. Mongoose calls this function
 // on every MG_* event.
 //
@@ -74,8 +81,7 @@ enum mg_event {
 //   If handler returns NULL, that means that handler has not processed
 //   the request. Handler must not send any data to the client in this case.
 //   Mongoose proceeds with request handling as if nothing happened.
-typedef void * (*mg_callback_t)(enum mg_event event,
-                                struct mg_connection *conn);
+typedef void *(*mg_callback_t)(enum mg_event event, struct mg_connection *conn);
 
 
 // Start web server.

test/unit_test.c

@@ -196,7 +196,21 @@ static void test_mg_fetch(void) {
   mg_stop(ctx);
 }
 
+static void test_base64_encode(void) {
+  const char *in[] = {"a", "ab", "abc", "abcd", NULL};
+  const char *out[] = {"YQ==", "YWI=", "YWJj", "YWJjZA=="};
+  char buf[100];
+  int i;
+
+  for (i = 0; in[i] != NULL; i++) {
+    base64_encode((unsigned char *) in[i], strlen(in[i]), buf);
+    printf("[%s] [%s]\n", out[i], buf);
+    ASSERT(!strcmp(buf, out[i]));
+  }
+}
+
 int main(void) {
+  test_base64_encode();
   test_match_prefix();
   test_remove_double_dots();
   test_should_keep_alive();