Binary header encoding.

Also fixes a rather embarrassing bug in bin_encoder.c.
	Change on 2014/12/12 by ctiller <ctiller@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82024795

7 files changed, 310 insertions, 80 deletions

diff --git a/src/core/transport/chttp2/bin_encoder.c b/src/core/transport/chttp2/bin_encoder.c
index 39a303bce9..e3b5fe9fcf 100644
--- a/src/core/transport/chttp2/bin_encoder.c
+++ b/src/core/transport/chttp2/bin_encoder.c
@@ -32,6 +32,9 @@
  */
 
 #include "src/core/transport/chttp2/bin_encoder.h"
+
+#include <string.h>
+
 #include "src/core/transport/chttp2/huffsyms.h"
 #include <grpc/support/log.h>
 
@@ -123,7 +126,7 @@ gpr_slice grpc_chttp2_base64_encode(gpr_slice input) {
   /* encode full triplets */
   for (i = 0; i < input_triplets; i++) {
     out[0] = alphabet[in[0] >> 2];
-    out[1] = alphabet[((in[0] & 0x2) << 4) | (in[1] >> 4)];
+    out[1] = alphabet[((in[0] & 0x3) << 4) | (in[1] >> 4)];
     out[2] = alphabet[((in[1] & 0xf) << 2) | (in[2] >> 6)];
     out[3] = alphabet[in[2] & 0x3f];
     out += 4;
@@ -136,13 +139,13 @@ gpr_slice grpc_chttp2_base64_encode(gpr_slice input) {
       break;
     case 1:
       out[0] = alphabet[in[0] >> 2];
-      out[1] = alphabet[(in[0] & 0x2) << 4];
+      out[1] = alphabet[(in[0] & 0x3) << 4];
       out += 2;
       in += 1;
       break;
     case 2:
       out[0] = alphabet[in[0] >> 2];
-      out[1] = alphabet[((in[0] & 0x2) << 4) | (in[1] >> 4)];
+      out[1] = alphabet[((in[0] & 0x3) << 4) | (in[1] >> 4)];
       out[2] = alphabet[(in[1] & 0xf) << 2];
       out += 3;
       in += 2;
@@ -238,7 +241,7 @@ gpr_slice grpc_chttp2_base64_encode_and_huffman_compress(gpr_slice input) {
 
   /* encode full triplets */
   for (i = 0; i < input_triplets; i++) {
-    enc_add2(&out, in[0] >> 2, ((in[0] & 0x2) << 4) | (in[1] >> 4));
+    enc_add2(&out, in[0] >> 2, ((in[0] & 0x3) << 4) | (in[1] >> 4));
     enc_add2(&out, ((in[1] & 0xf) << 2) | (in[2] >> 6), in[2] & 0x3f);
     in += 3;
   }
@@ -248,11 +251,11 @@ gpr_slice grpc_chttp2_base64_encode_and_huffman_compress(gpr_slice input) {
     case 0:
       break;
     case 1:
-      enc_add2(&out, in[0] >> 2, (in[0] & 0x2) << 4);
+      enc_add2(&out, in[0] >> 2, (in[0] & 0x3) << 4);
       in += 1;
       break;
     case 2:
-      enc_add2(&out, in[0] >> 2, ((in[0] & 0x2) << 4) | (in[1] >> 4));
+      enc_add2(&out, in[0] >> 2, ((in[0] & 0x3) << 4) | (in[1] >> 4));
       enc_add1(&out, (in[1] & 0xf) << 2);
       in += 2;
       break;
@@ -269,3 +272,8 @@ gpr_slice grpc_chttp2_base64_encode_and_huffman_compress(gpr_slice input) {
   GPR_ASSERT(in == GPR_SLICE_END_PTR(input));
   return output;
 }
+
+int grpc_is_binary_header(const char *key, size_t length) {
+  if (length < 5) return 0;
+  return 0 == memcmp(key + length - 4, "-bin", 4);
+}
diff --git a/src/core/transport/chttp2/bin_encoder.h b/src/core/transport/chttp2/bin_encoder.h
index 86031137dc..2310f841f8 100644
--- a/src/core/transport/chttp2/bin_encoder.h
+++ b/src/core/transport/chttp2/bin_encoder.h
@@ -51,4 +51,6 @@ gpr_slice grpc_chttp2_huffman_compress(gpr_slice input);
    return y; */
 gpr_slice grpc_chttp2_base64_encode_and_huffman_compress(gpr_slice input);
 
+int grpc_is_binary_header(const char *key, size_t length);
+
 #endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_BIN_ENCODER_H_ */
diff --git a/src/core/transport/chttp2/gen_hpack_tables.c b/src/core/transport/chttp2/gen_hpack_tables.c
index 301b79ef2c..3b9e8ed4dc 100644
--- a/src/core/transport/chttp2/gen_hpack_tables.c
+++ b/src/core/transport/chttp2/gen_hpack_tables.c
@@ -332,10 +332,29 @@ static void generate_base64_huff_encoder_table() {
   printf("};\n");
 }
 
+static void generate_base64_inverse_table() {
+  static const char alphabet[] =
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+  unsigned char inverse[256];
+  int i;
+
+  memset(inverse, 255, sizeof(inverse));
+  for (i = 0; i < strlen(alphabet); i++) {
+    inverse[(unsigned char)alphabet[i]] = i;
+  }
+
+  printf("static const gpr_uint8 inverse_base64[256] = {");
+  for (i = 0; i < 256; i++) {
+    printf("%d,", inverse[i]);
+  }
+  printf("};\n");
+}
+
 int main(void) {
   generate_huff_tables();
   generate_first_byte_lut();
   generate_base64_huff_encoder_table();
+  generate_base64_inverse_table();
 
   return 0;
 }
diff --git a/src/core/transport/chttp2/hpack_parser.c b/src/core/transport/chttp2/hpack_parser.c
index 33588a73d4..246935fd79 100644
--- a/src/core/transport/chttp2/hpack_parser.c
+++ b/src/core/transport/chttp2/hpack_parser.c
@@ -37,13 +37,21 @@
 #include <string.h>
 #include <assert.h>
 
-#include "src/core/support/murmur_hash.h"
+#include "src/core/transport/chttp2/bin_encoder.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/port_platform.h>
 #include <grpc/support/string.h>
 #include <grpc/support/useful.h>
 
+typedef enum {
+  NOT_BINARY,
+  B64_BYTE0,
+  B64_BYTE1,
+  B64_BYTE2,
+  B64_BYTE3
+} binary_state;
+
 /* How parsing works:
 
    The parser object keeps track of a function pointer which represents the
@@ -68,8 +76,12 @@ static int parse_string_prefix(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end);
 static int parse_key_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                             const gpr_uint8 *end);
-static int parse_value_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
-                              const gpr_uint8 *end);
+static int parse_value_string_with_indexed_key(grpc_chttp2_hpack_parser *p,
+                                               const gpr_uint8 *cur,
+                                               const gpr_uint8 *end);
+static int parse_value_string_with_literal_key(grpc_chttp2_hpack_parser *p,
+                                               const gpr_uint8 *cur,
+                                               const gpr_uint8 *end);
 
 static int parse_value0(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                         const gpr_uint8 *end);
@@ -582,6 +594,27 @@ static const gpr_int16 emit_sub_tbl[249 * 16] = {
     13,  22,  22,  22,  22,  256, 256, 256, 256,
 };
 
+static const gpr_uint8 inverse_base64[256] = {
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62,  255,
+    255, 255, 63,  52,  53,  54,  55,  56,  57,  58,  59,  60,  61,  255, 255,
+    255, 64,  255, 255, 255, 0,   1,   2,   3,   4,   5,   6,   7,   8,   9,
+    10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,
+    25,  255, 255, 255, 255, 255, 255, 26,  27,  28,  29,  30,  31,  32,  33,
+    34,  35,  36,  37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,
+    49,  50,  51,  255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+    255,
+};
+
 /* emission helpers */
 static void on_hdr(grpc_chttp2_hpack_parser *p, grpc_mdelem *md,
                    int add_to_table) {
@@ -724,7 +757,7 @@ static int finish_lithdr_incidx_v(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_incidx(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_value_string, finish_lithdr_incidx};
+      parse_value_string_with_indexed_key, finish_lithdr_incidx};
   p->next_state = and_then;
   p->index = (*cur) & 0x3f;
   return parse_string_prefix(p, cur + 1, end);
@@ -734,7 +767,8 @@ static int parse_lithdr_incidx(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_incidx_x(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_string_prefix, parse_value_string, finish_lithdr_incidx};
+      parse_string_prefix, parse_value_string_with_indexed_key,
+      finish_lithdr_incidx};
   p->next_state = and_then;
   p->index = 0x3f;
   p->parsing.value = &p->index;
@@ -745,8 +779,8 @@ static int parse_lithdr_incidx_x(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_incidx_v(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_key_string, parse_string_prefix, parse_value_string,
-      finish_lithdr_incidx_v};
+      parse_key_string, parse_string_prefix,
+      parse_value_string_with_literal_key, finish_lithdr_incidx_v};
   p->next_state = and_then;
   return parse_string_prefix(p, cur + 1, end);
 }
@@ -776,7 +810,7 @@ static int finish_lithdr_notidx_v(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_notidx(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_value_string, finish_lithdr_notidx};
+      parse_value_string_with_indexed_key, finish_lithdr_notidx};
   p->next_state = and_then;
   p->index = (*cur) & 0xf;
   return parse_string_prefix(p, cur + 1, end);
@@ -786,7 +820,8 @@ static int parse_lithdr_notidx(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_notidx_x(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_string_prefix, parse_value_string, finish_lithdr_notidx};
+      parse_string_prefix, parse_value_string_with_indexed_key,
+      finish_lithdr_notidx};
   p->next_state = and_then;
   p->index = 0xf;
   p->parsing.value = &p->index;
@@ -797,8 +832,8 @@ static int parse_lithdr_notidx_x(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_notidx_v(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_key_string, parse_string_prefix, parse_value_string,
-      finish_lithdr_notidx_v};
+      parse_key_string, parse_string_prefix,
+      parse_value_string_with_literal_key, finish_lithdr_notidx_v};
   p->next_state = and_then;
   return parse_string_prefix(p, cur + 1, end);
 }
@@ -828,7 +863,7 @@ static int finish_lithdr_nvridx_v(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_nvridx(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_value_string, finish_lithdr_nvridx};
+      parse_value_string_with_indexed_key, finish_lithdr_nvridx};
   p->next_state = and_then;
   p->index = (*cur) & 0xf;
   return parse_string_prefix(p, cur + 1, end);
@@ -838,7 +873,8 @@ static int parse_lithdr_nvridx(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_nvridx_x(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_string_prefix, parse_value_string, finish_lithdr_nvridx};
+      parse_string_prefix, parse_value_string_with_indexed_key,
+      finish_lithdr_nvridx};
   p->next_state = and_then;
   p->index = 0xf;
   p->parsing.value = &p->index;
@@ -849,8 +885,8 @@ static int parse_lithdr_nvridx_x(grpc_chttp2_hpack_parser *p,
 static int parse_lithdr_nvridx_v(grpc_chttp2_hpack_parser *p,
                                  const gpr_uint8 *cur, const gpr_uint8 *end) {
   static const grpc_chttp2_hpack_parser_state and_then[] = {
-      parse_key_string, parse_string_prefix, parse_value_string,
-      finish_lithdr_nvridx_v};
+      parse_key_string, parse_string_prefix,
+      parse_value_string_with_literal_key, finish_lithdr_nvridx_v};
   p->next_state = and_then;
   return parse_string_prefix(p, cur + 1, end);
 }
@@ -1043,8 +1079,8 @@ static int parse_string_prefix(grpc_chttp2_hpack_parser *p,
 }
 
 /* append some bytes to a string */
-static void append_string(grpc_chttp2_hpack_parser_string *str,
-                          const gpr_uint8 *data, size_t length) {
+static void append_bytes(grpc_chttp2_hpack_parser_string *str,
+                         const gpr_uint8 *data, size_t length) {
   if (length + str->length > str->capacity) {
     str->capacity = str->length + length;
     str->str = gpr_realloc(str->str, str->capacity);
@@ -1053,45 +1089,156 @@ static void append_string(grpc_chttp2_hpack_parser_string *str,
   str->length += length;
 }
 
+static int append_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
+                         const gpr_uint8 *end) {
+  grpc_chttp2_hpack_parser_string *str = p->parsing.str;
+  gpr_uint32 bits;
+  gpr_uint8 decoded[3];
+  switch ((binary_state)p->binary) {
+    case NOT_BINARY:
+      append_bytes(str, cur, end - cur);
+      return 1;
+    b64_byte0:
+    case B64_BYTE0:
+      if (cur == end) {
+        p->binary = B64_BYTE0;
+        return 1;
+      }
+      bits = inverse_base64[*cur];
+      ++cur;
+      if (bits == 255)
+        return 0;
+      else if (bits == 64)
+        goto b64_byte0;
+      p->base64_buffer = bits << 18;
+    /* fallthrough */
+    b64_byte1:
+    case B64_BYTE1:
+      if (cur == end) {
+        p->binary = B64_BYTE1;
+        return 1;
+      }
+      bits = inverse_base64[*cur];
+      ++cur;
+      if (bits == 255)
+        return 0;
+      else if (bits == 64)
+        goto b64_byte1;
+      p->base64_buffer |= bits << 12;
+    /* fallthrough */
+    b64_byte2:
+    case B64_BYTE2:
+      if (cur == end) {
+        p->binary = B64_BYTE2;
+        return 1;
+      }
+      bits = inverse_base64[*cur];
+      ++cur;
+      if (bits == 255)
+        return 0;
+      else if (bits == 64)
+        goto b64_byte2;
+      p->base64_buffer |= bits << 6;
+    /* fallthrough */
+    b64_byte3:
+    case B64_BYTE3:
+      if (cur == end) {
+        p->binary = B64_BYTE3;
+        return 1;
+      }
+      bits = inverse_base64[*cur];
+      ++cur;
+      if (bits == 255)
+        return 0;
+      else if (bits == 64)
+        goto b64_byte3;
+      p->base64_buffer |= bits;
+      bits = p->base64_buffer;
+      decoded[0] = bits >> 16;
+      decoded[1] = bits >> 8;
+      decoded[2] = bits;
+      append_bytes(str, decoded, 3);
+      goto b64_byte0;
+  }
+  gpr_log(GPR_ERROR, "should never reach here");
+  abort();
+  return 1;
+}
+
 /* append a null terminator to a string */
-static void finish_str(grpc_chttp2_hpack_parser_string *str) {
+static int finish_str(grpc_chttp2_hpack_parser *p) {
   gpr_uint8 terminator = 0;
-  append_string(str, &terminator, 1);
-  str->length--; /* don't actually count the null terminator */
+  gpr_uint8 decoded[2];
+  gpr_uint32 bits;
+  grpc_chttp2_hpack_parser_string *str = p->parsing.str;
+  switch ((binary_state)p->binary) {
+    case NOT_BINARY:
+      break;
+    case B64_BYTE0:
+      break;
+    case B64_BYTE1:
+      gpr_log(GPR_ERROR, "illegal base64 encoding");
+      return 0; /* illegal encoding */
+    case B64_BYTE2:
+      bits = p->base64_buffer;
+      if (bits & 0xffff) {
+        gpr_log(GPR_ERROR, "trailing bits in base64 encoding: 0x%04x",
+                bits & 0xffff);
+        return 0;
+      }
+      decoded[0] = bits >> 16;
+      append_bytes(str, decoded, 1);
+      break;
+    case B64_BYTE3:
+      bits = p->base64_buffer;
+      if (bits & 0xff) {
+        gpr_log(GPR_ERROR, "trailing bits in base64 encoding: 0x%02x",
+                bits & 0xff);
+        return 0;
+      }
+      decoded[0] = bits >> 16;
+      decoded[1] = bits >> 8;
+      append_bytes(str, decoded, 2);
+      break;
+  }
+  append_bytes(str, &terminator, 1);
+  p->parsing.str->length--; /* don't actually count the null terminator */
+  return 1;
 }
 
 /* decode a nibble from a huffman encoded stream */
-static void huff_nibble(grpc_chttp2_hpack_parser *p, gpr_uint8 nibble) {
+static int huff_nibble(grpc_chttp2_hpack_parser *p, gpr_uint8 nibble) {
   gpr_int16 emit = emit_sub_tbl[16 * emit_tbl[p->huff_state] + nibble];
   gpr_int16 next = next_sub_tbl[16 * next_tbl[p->huff_state] + nibble];
   if (emit != -1) {
     if (emit >= 0 && emit < 256) {
       gpr_uint8 c = emit;
-      append_string(p->parsing.str, &c, 1);
+      if (!append_string(p, &c, (&c) + 1)) return 0;
     } else {
       assert(emit == 256);
     }
   }
   p->huff_state = next;
+  return 1;
 }
 
 /* decode full bytes from a huffman encoded stream */
-static void add_huff_bytes(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
-                           const gpr_uint8 *end) {
+static int add_huff_bytes(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
+                          const gpr_uint8 *end) {
   for (; cur != end; ++cur) {
-    huff_nibble(p, *cur >> 4);
-    huff_nibble(p, *cur & 0xf);
+    if (!huff_nibble(p, *cur >> 4) || !huff_nibble(p, *cur & 0xf)) return 0;
   }
+  return 1;
 }
 
 /* decode some string bytes based on the current decoding mode
    (huffman or not) */
-static void add_str_bytes(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
-                          const gpr_uint8 *end) {
+static int add_str_bytes(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
+                         const gpr_uint8 *end) {
   if (p->huff) {
-    add_huff_bytes(p, cur, end);
+    return add_huff_bytes(p, cur, end);
   } else {
-    append_string(p->parsing.str, cur, end - cur);
+    return append_string(p, cur, end);
   }
 }
 
@@ -1101,11 +1248,10 @@ static int parse_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
   size_t remaining = p->strlen - p->strgot;
   size_t given = end - cur;
   if (remaining <= given) {
-    add_str_bytes(p, cur, cur + remaining);
-    finish_str(p->parsing.str);
-    return parse_next(p, cur + remaining, end);
+    return add_str_bytes(p, cur, cur + remaining) && finish_str(p) &&
+           parse_next(p, cur + remaining, end);
   } else {
-    add_str_bytes(p, cur, cur + given);
+    if (!add_str_bytes(p, cur, cur + given)) return 0;
     p->strgot += given;
     p->state = parse_string;
     return 1;
@@ -1114,25 +1260,63 @@ static int parse_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
 
 /* begin parsing a string - performs setup, calls parse_string */
 static int begin_parse_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
-                              const gpr_uint8 *end,
+                              const gpr_uint8 *end, gpr_uint8 binary,
                               grpc_chttp2_hpack_parser_string *str) {
   p->strgot = 0;
   str->length = 0;
   p->parsing.str = str;
   p->huff_state = 0;
+  p->binary = binary;
   return parse_string(p, cur, end);
 }
 
 /* parse the key string */
 static int parse_key_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                             const gpr_uint8 *end) {
-  return begin_parse_string(p, cur, end, &p->key);
+  return begin_parse_string(p, cur, end, NOT_BINARY, &p->key);
+}
+
+/* check if a key represents a binary header or not */
+typedef enum { BINARY_HEADER, PLAINTEXT_HEADER, ERROR_HEADER } is_binary_header;
+
+static is_binary_header is_binary_literal_header(grpc_chttp2_hpack_parser *p) {
+  return grpc_is_binary_header(p->key.str, p->key.length) ? BINARY_HEADER
+                                                          : PLAINTEXT_HEADER;
+}
+
+static is_binary_header is_binary_indexed_header(grpc_chttp2_hpack_parser *p) {
+  grpc_mdelem *elem = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  if (!elem) return ERROR_HEADER;
+  return grpc_is_binary_header(
+             (const char *)GPR_SLICE_START_PTR(elem->key->slice),
+             GPR_SLICE_LENGTH(elem->key->slice))
+             ? BINARY_HEADER
+             : PLAINTEXT_HEADER;
 }
 
 /* parse the value string */
 static int parse_value_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
-                              const gpr_uint8 *end) {
-  return begin_parse_string(p, cur, end, &p->value);
+                              const gpr_uint8 *end, is_binary_header type) {
+  switch (type) {
+    case BINARY_HEADER:
+      return begin_parse_string(p, cur, end, B64_BYTE0, &p->value);
+    case PLAINTEXT_HEADER:
+      return begin_parse_string(p, cur, end, NOT_BINARY, &p->value);
+    case ERROR_HEADER:
+      return 0;
+  }
+}
+
+static int parse_value_string_with_indexed_key(grpc_chttp2_hpack_parser *p,
+                                               const gpr_uint8 *cur,
+                                               const gpr_uint8 *end) {
+  return parse_value_string(p, cur, end, is_binary_indexed_header(p));
+}
+
+static int parse_value_string_with_literal_key(grpc_chttp2_hpack_parser *p,
+                                               const gpr_uint8 *cur,
+                                               const gpr_uint8 *end) {
+  return parse_value_string(p, cur, end, is_binary_literal_header(p));
 }
 
 /* PUBLIC INTERFACE */
diff --git a/src/core/transport/chttp2/hpack_parser.h b/src/core/transport/chttp2/hpack_parser.h
index cf68042fbd..799513e7ff 100644
--- a/src/core/transport/chttp2/hpack_parser.h
+++ b/src/core/transport/chttp2/hpack_parser.h
@@ -78,12 +78,15 @@ struct grpc_chttp2_hpack_parser {
   gpr_uint32 strgot;
   /* huffman decoding state */
   gpr_uint16 huff_state;
+  /* is the string being decoded binary? */
+  gpr_uint8 binary;
   /* is the current string huffman encoded? */
   gpr_uint8 huff;
   /* set by higher layers, used by grpc_chttp2_header_parser_parse to signal
      it should append a metadata boundary at the end of frame */
   gpr_uint8 is_boundary;
   gpr_uint8 is_eof;
+  gpr_uint32 base64_buffer;
 
   /* hpack table */
   grpc_chttp2_hptbl table;
diff --git a/src/core/transport/chttp2/stream_encoder.c b/src/core/transport/chttp2/stream_encoder.c
index d46366d8b2..07eeb0a474 100644
--- a/src/core/transport/chttp2/stream_encoder.c
+++ b/src/core/transport/chttp2/stream_encoder.c
@@ -38,6 +38,7 @@
 
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
+#include "src/core/transport/chttp2/bin_encoder.h"
 #include "src/core/transport/chttp2/hpack_table.h"
 #include "src/core/transport/chttp2/timeout_encoding.h"
 #include "src/core/transport/chttp2/varint.h"
@@ -269,62 +270,79 @@ static void emit_indexed(grpc_chttp2_hpack_compressor *c, gpr_uint32 index,
   GRPC_CHTTP2_WRITE_VARINT(index, 1, 0x80, add_tiny_header_data(st, len), len);
 }
 
+static gpr_slice get_wire_value(grpc_mdelem *elem, gpr_uint8 *huffman_prefix) {
+  if (grpc_is_binary_header((const char *)GPR_SLICE_START_PTR(elem->key->slice),
+                            GPR_SLICE_LENGTH(elem->key->slice))) {
+    *huffman_prefix = 0x80;
+    return grpc_mdstr_as_base64_encoded_and_huffman_compressed(elem->value);
+  }
+  /* TODO(ctiller): opportunistically compress non-binary headers */
+  *huffman_prefix = 0x00;
+  return elem->value->slice;
+}
+
 static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c,
-                               gpr_uint32 key_index, grpc_mdstr *value,
+                               gpr_uint32 key_index, grpc_mdelem *elem,
                                framer_state *st) {
   int len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 2);
-  int len_val = GPR_SLICE_LENGTH(value->slice);
+  gpr_uint8 huffman_prefix;
+  gpr_slice value_slice = get_wire_value(elem, &huffman_prefix);
+  int len_val = GPR_SLICE_LENGTH(value_slice);
   int len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   GRPC_CHTTP2_WRITE_VARINT(key_index, 2, 0x40,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, 0x00,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, gpr_slice_ref(value->slice));
+  add_header_data(st, gpr_slice_ref(value_slice));
 }
 
 static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
-                              gpr_uint32 key_index, grpc_mdstr *value,
+                              gpr_uint32 key_index, grpc_mdelem *elem,
                               framer_state *st) {
   int len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 4);
-  int len_val = GPR_SLICE_LENGTH(value->slice);
+  gpr_uint8 huffman_prefix;
+  gpr_slice value_slice = get_wire_value(elem, &huffman_prefix);
+  int len_val = GPR_SLICE_LENGTH(value_slice);
   int len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   GRPC_CHTTP2_WRITE_VARINT(key_index, 4, 0x00,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, 0x00,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, gpr_slice_ref(value->slice));
+  add_header_data(st, gpr_slice_ref(value_slice));
 }
 
 static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
-                                 grpc_mdstr *key, grpc_mdstr *value,
-                                 framer_state *st) {
-  int len_key = GPR_SLICE_LENGTH(key->slice);
-  int len_val = GPR_SLICE_LENGTH(value->slice);
+                                 grpc_mdelem *elem, framer_state *st) {
+  int len_key = GPR_SLICE_LENGTH(elem->key->slice);
+  gpr_uint8 huffman_prefix;
+  gpr_slice value_slice = get_wire_value(elem, &huffman_prefix);
+  int len_val = GPR_SLICE_LENGTH(value_slice);
   int len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1);
   int len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   *add_tiny_header_data(st, 1) = 0x40;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, gpr_slice_ref(key->slice));
-  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, 0x00,
+  add_header_data(st, gpr_slice_ref(elem->key->slice));
+  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, gpr_slice_ref(value->slice));
+  add_header_data(st, gpr_slice_ref(value_slice));
 }
 
 static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
-                                grpc_mdstr *key, grpc_mdstr *value,
-                                framer_state *st) {
-  int len_key = GPR_SLICE_LENGTH(key->slice);
-  int len_val = GPR_SLICE_LENGTH(value->slice);
+                                grpc_mdelem *elem, framer_state *st) {
+  int len_key = GPR_SLICE_LENGTH(elem->key->slice);
+  gpr_uint8 huffman_prefix;
+  gpr_slice value_slice = get_wire_value(elem, &huffman_prefix);
+  int len_val = GPR_SLICE_LENGTH(value_slice);
   int len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1);
   int len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   *add_tiny_header_data(st, 1) = 0x00;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, gpr_slice_ref(key->slice));
-  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, 0x00,
+  add_header_data(st, gpr_slice_ref(elem->key->slice));
+  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, gpr_slice_ref(value->slice));
+  add_header_data(st, gpr_slice_ref(value_slice));
 }
 
 static gpr_uint32 dynidx(grpc_chttp2_hpack_compressor *c, gpr_uint32 index) {
@@ -338,6 +356,7 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
   gpr_uint32 key_hash = elem->key->hash;
   gpr_uint32 elem_hash = key_hash ^ elem->value->hash;
   size_t decoder_space_usage;
+  gpr_uint32 indices_key;
   int should_add_elem;
 
   inc_filter(HASH_FRAGMENT_1(elem_hash), &c->filter_elems_sum, c->filter_elems);
@@ -371,35 +390,29 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
 
   /* no hits for the elem... maybe there's a key? */
 
+  indices_key = c->indices_keys[HASH_FRAGMENT_2(key_hash)];
   if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == elem->key &&
-      c->indices_keys[HASH_FRAGMENT_2(key_hash)] > c->tail_remote_index) {
+      indices_key > c->tail_remote_index) {
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
-      emit_lithdr_incidx(c,
-                         dynidx(c, c->indices_keys[HASH_FRAGMENT_2(key_hash)]),
-                         elem->value, st);
+      emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st);
       add_elem(c, elem);
     } else {
-      emit_lithdr_noidx(c,
-                        dynidx(c, c->indices_keys[HASH_FRAGMENT_2(key_hash)]),
-                        elem->value, st);
+      emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
       grpc_mdelem_unref(elem);
     }
     return;
   }
 
+  indices_key = c->indices_keys[HASH_FRAGMENT_3(key_hash)];
   if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key &&
-      c->indices_keys[HASH_FRAGMENT_3(key_hash)] > c->tail_remote_index) {
+      indices_key > c->tail_remote_index) {
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
-      emit_lithdr_incidx(c,
-                         dynidx(c, c->indices_keys[HASH_FRAGMENT_3(key_hash)]),
-                         elem->value, st);
+      emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st);
       add_elem(c, elem);
     } else {
-      emit_lithdr_noidx(c,
-                        dynidx(c, c->indices_keys[HASH_FRAGMENT_3(key_hash)]),
-                        elem->value, st);
+      emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
       grpc_mdelem_unref(elem);
     }
     return;
@@ -408,10 +421,10 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
   /* no elem, key in the table... fall back to literal emission */
 
   if (should_add_elem) {
-    emit_lithdr_incidx_v(c, elem->key, elem->value, st);
+    emit_lithdr_incidx_v(c, elem, st);
     add_elem(c, elem);
   } else {
-    emit_lithdr_noidx_v(c, elem->key, elem->value, st);
+    emit_lithdr_noidx_v(c, elem, st);
     grpc_mdelem_unref(elem);
   }
 }
diff --git a/src/core/transport/metadata.c b/src/core/transport/metadata.c
index 9edfd5bfd1..1a869cfbc5 100644
--- a/src/core/transport/metadata.c
+++ b/src/core/transport/metadata.c
@@ -540,6 +540,7 @@ gpr_slice grpc_mdstr_as_base64_encoded_and_huffman_compressed(grpc_mdstr *gs) {
   if (!s->has_base64_and_huffman_encoded) {
     s->base64_and_huffman =
         grpc_chttp2_base64_encode_and_huffman_compress(s->slice);
+    s->has_base64_and_huffman_encoded = 1;
   }
   slice = s->base64_and_huffman;
   unlock(ctx);