Add Version Negotiation encoder

lib/includes/ngtcp2/ngtcp2.h

@@ -309,9 +309,9 @@ NGTCP2_EXTERN void ngtcp2_upe_padding(ngtcp2_upe *upe);
  * :enum:`NGTCP2_ERR_NOBUF`
  *     Buffer does not have enough capacity to write a payload.
  */
-NGTCP2_EXTERN int
-ngtcp2_upe_encode_version_negotiation(ngtcp2_upe *upe, uint8_t *out,
-                                      size_t outlen, uint32_t *sv, size_t nsv);
+NGTCP2_EXTERN int ngtcp2_upe_encode_version_negotiation(ngtcp2_upe *upe,
+                                                        const uint32_t *sv,
+                                                        size_t nsv);
 
 /**
  * @function

lib/ngtcp2_upe.c

@@ -80,6 +80,29 @@ void ngtcp2_upe_padding(ngtcp2_upe *upe) {
   buf->last += len;
 }
 
+int ngtcp2_upe_encode_version_negotiation(ngtcp2_upe *upe, const uint32_t *sv,
+                                          size_t nsv) {
+  ngtcp2_buf *buf = &upe->buf;
+  uint8_t *p;
+  size_t i;
+
+  if (ngtcp2_buf_left(buf) < sizeof(uint32_t) * nsv + NGTCP2_PKT_MDLEN) {
+    return NGTCP2_ERR_NOBUF;
+  }
+
+  p = buf->last;
+
+  for (i = 0; i < nsv; ++i) {
+    p = ngtcp2_put_uint32be(p, sv[i]);
+  }
+
+  assert((size_t)(p - buf->last) == sizeof(uint32_t) * nsv);
+
+  buf->last = p;
+
+  return 0;
+}
+
 size_t ngtcp2_upe_final(ngtcp2_upe *upe, const uint8_t **ppkt) {
   ngtcp2_buf *buf = &upe->buf;
   uint64_t h;

tests/main.c

@@ -68,7 +68,9 @@ int main() {
                    test_ngtcp2_pkt_encode_stream_frame) ||
       !CU_add_test(pSuite, "pkt_encode_ack_frame",
                    test_ngtcp2_pkt_encode_ack_frame) ||
-      !CU_add_test(pSuite, "upe_encode", test_ngtcp2_upe_encode)) {
+      !CU_add_test(pSuite, "upe_encode", test_ngtcp2_upe_encode) ||
+      !CU_add_test(pSuite, "upe_encode_version_negotiation",
+                   test_ngtcp2_upe_encode_version_negotiation)) {
     CU_cleanup_registry();
     return CU_get_error();
   }

tests/ngtcp2_test_helper.h

@@ -36,6 +36,11 @@
  */
 #define strsize(S) (sizeof(S) - 1)
 
+/*
+ * arraylen macro returns the number of elements in array |A|.
+ */
+#define arraylen(A) (sizeof(A) / sizeof(A[0]))
+
 /*
  * ngtcp2_t_encode_stream_frame encodes STREAM frame into |out| with
  * the given parameters.  If NGTCP2_STREAM_D_BIT is set in |flags|,

tests/ngtcp2_upe_test.c

@@ -30,6 +30,7 @@
 
 #include "ngtcp2_upe.h"
 #include "ngtcp2_pkt.h"
+#include "ngtcp2_conv.h"
 #include "ngtcp2_test_helper.h"
 
 void test_ngtcp2_upe_encode(void) {
@@ -136,3 +137,48 @@ void test_ngtcp2_upe_encode(void) {
   CU_ASSERT(NGTCP2_FRAME_PADDING == ns.type);
   CU_ASSERT(pktlen == ns.padding.len);
 }
+
+void test_ngtcp2_upe_encode_version_negotiation(void) {
+  ngtcp2_upe upe;
+  const uint32_t sv[] = {0x01, 0x02, 0x03};
+  uint8_t buf[256];
+  ngtcp2_pkt_hd hd, nhd;
+  int rv;
+  const uint8_t *out;
+  size_t pktlen;
+  ssize_t nread;
+  size_t i;
+
+  ngtcp2_upe_init(&upe, buf, sizeof(buf));
+
+  hd.flags = NGTCP2_PKT_FLAG_LONG_FORM;
+  hd.type = NGTCP2_PKT_VERSION_NEGOTIATION;
+  hd.conn_id = 1000000009;
+  hd.pkt_num = 1000000007;
+  hd.version = 0xff;
+
+  rv = ngtcp2_upe_encode_hd(&upe, &hd);
+
+  CU_ASSERT(0 == rv);
+
+  rv = ngtcp2_upe_encode_version_negotiation(&upe, sv, arraylen(sv));
+
+  CU_ASSERT(0 == rv);
+
+  pktlen = ngtcp2_upe_final(&upe, &out);
+  pktlen -= NGTCP2_PKT_MDLEN;
+
+  nread = ngtcp2_pkt_decode_hd_long(&nhd, out, pktlen);
+
+  CU_ASSERT(NGTCP2_LONG_HEADERLEN == nread);
+
+  out += nread;
+  pktlen -= (size_t)nread;
+
+  CU_ASSERT(sizeof(sv) == pktlen);
+
+  for (i = 0; i < arraylen(sv); ++i) {
+    uint32_t v = ngtcp2_get_uint32(out + sizeof(uint32_t) * i);
+    CU_ASSERT(sv[i] == v);
+  }
+}

tests/ngtcp2_upe_test.h

@@ -30,5 +30,6 @@
 #endif /* HAVE_CONFIG_H */
 
 void test_ngtcp2_upe_encode(void);
+void test_ngtcp2_upe_encode_version_negotiation(void);
 
 #endif /* NGTCP2_UPE_TEST_H */