1 files changed, 230 insertions, 0 deletions
diff --git a/lib/ngtcp2_ppe.c b/lib/ngtcp2_ppe.c
new file mode 100644
index 0000000..82aa80c
--- /dev/null
+++ b/lib/ngtcp2_ppe.c
@@ -0,0 +1,230 @@
+/*
+ * ngtcp2
+ *
+ * Copyright (c) 2017 ngtcp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "ngtcp2_ppe.h"
+
+#include <string.h>
+#include <assert.h>
+
+#include "ngtcp2_str.h"
+#include "ngtcp2_conv.h"
+
+void ngtcp2_ppe_init(ngtcp2_ppe *ppe, uint8_t *out, size_t outlen,
+                     ngtcp2_crypto_cc *cc) {
+  ngtcp2_buf_init(&ppe->buf, out, outlen);
+
+  ppe->hdlen = 0;
+  ppe->len_offset = 0;
+  ppe->pkt_num_offset = 0;
+  ppe->pkt_numlen = 0;
+  ppe->pkt_num = 0;
+  ppe->sample_offset = 0;
+  ppe->cc = cc;
+}
+
+int ngtcp2_ppe_encode_hd(ngtcp2_ppe *ppe, const ngtcp2_pkt_hd *hd) {
+  ngtcp2_ssize rv;
+  ngtcp2_buf *buf = &ppe->buf;
+  ngtcp2_crypto_cc *cc = ppe->cc;
+
+  if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
+    return NGTCP2_ERR_NOBUF;
+  }
+
+  if (hd->flags & NGTCP2_PKT_FLAG_LONG_FORM) {
+    ppe->len_offset = 1 + 4 + 1 + hd->dcid.datalen + 1 + hd->scid.datalen;
+    if (hd->type == NGTCP2_PKT_INITIAL) {
+      ppe->len_offset += ngtcp2_put_uvarintlen(hd->token.len) + hd->token.len;
+    }
+    ppe->pkt_num_offset = ppe->len_offset + NGTCP2_PKT_LENGTHLEN;
+    rv = ngtcp2_pkt_encode_hd_long(
+        buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
+  } else {
+    ppe->pkt_num_offset = 1 + hd->dcid.datalen;
+    rv = ngtcp2_pkt_encode_hd_short(
+        buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
+  }
+  if (rv < 0) {
+    return (int)rv;
+  }
+
+  ppe->sample_offset = ppe->pkt_num_offset + 4;
+
+  buf->last += rv;
+
+  ppe->pkt_numlen = hd->pkt_numlen;
+  ppe->hdlen = (size_t)rv;
+
+  ppe->pkt_num = hd->pkt_num;
+
+  return 0;
+}
+
+int ngtcp2_ppe_encode_frame(ngtcp2_ppe *ppe, ngtcp2_frame *fr) {
+  ngtcp2_ssize rv;
+  ngtcp2_buf *buf = &ppe->buf;
+  ngtcp2_crypto_cc *cc = ppe->cc;
+
+  if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
+    return NGTCP2_ERR_NOBUF;
+  }
+
+  rv = ngtcp2_pkt_encode_frame(
+      buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, fr);
+  if (rv < 0) {
+    return (int)rv;
+  }
+
+  buf->last += rv;
+
+  return 0;
+}
+
+ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt) {
+  ngtcp2_buf *buf = &ppe->buf;
+  ngtcp2_crypto_cc *cc = ppe->cc;
+  uint8_t *payload = buf->begin + ppe->hdlen;
+  size_t payloadlen = ngtcp2_buf_len(buf) - ppe->hdlen;
+  uint8_t mask[NGTCP2_HP_SAMPLELEN];
+  uint8_t *p;
+  size_t i;
+  int rv;
+
+  assert(cc->encrypt);
+  assert(cc->hp_mask);
+
+  if (ppe->len_offset) {
+    ngtcp2_put_uvarint30(
+        buf->begin + ppe->len_offset,
+        (uint16_t)(payloadlen + ppe->pkt_numlen + cc->aead.max_overhead));
+  }
+
+  ngtcp2_crypto_create_nonce(ppe->nonce, cc->ckm->iv.base, cc->ckm->iv.len,
+                             ppe->pkt_num);
+
+  rv = cc->encrypt(payload, &cc->aead, &cc->ckm->aead_ctx, payload, payloadlen,
+                   ppe->nonce, cc->ckm->iv.len, buf->begin, ppe->hdlen);
+  if (rv != 0) {
+    return NGTCP2_ERR_CALLBACK_FAILURE;
+  }
+
+  buf->last = payload + payloadlen + cc->aead.max_overhead;
+
+  /* TODO Check that we have enough space to get sample */
+  assert(ppe->sample_offset + NGTCP2_HP_SAMPLELEN <= ngtcp2_buf_len(buf));
+
+  rv = cc->hp_mask(mask, &cc->hp, &cc->hp_ctx, buf->begin + ppe->sample_offset);
+  if (rv != 0) {
+    return NGTCP2_ERR_CALLBACK_FAILURE;
+  }
+
+  p = buf->begin;
+  if (*p & NGTCP2_HEADER_FORM_BIT) {
+    *p = (uint8_t)(*p ^ (mask[0] & 0x0f));
+  } else {
+    *p = (uint8_t)(*p ^ (mask[0] & 0x1f));
+  }
+
+  p = buf->begin + ppe->pkt_num_offset;
+  for (i = 0; i < ppe->pkt_numlen; ++i) {
+    *(p + i) ^= mask[i + 1];
+  }
+
+  if (ppkt != NULL) {
+    *ppkt = buf->begin;
+  }
+
+  return (ngtcp2_ssize)ngtcp2_buf_len(buf);
+}
+
+size_t ngtcp2_ppe_left(ngtcp2_ppe *ppe) {
+  ngtcp2_crypto_cc *cc = ppe->cc;
+
+  if (ngtcp2_buf_left(&ppe->buf) < cc->aead.max_overhead) {
+    return 0;
+  }
+
+  return ngtcp2_buf_left(&ppe->buf) - cc->aead.max_overhead;
+}
+
+size_t ngtcp2_ppe_pktlen(ngtcp2_ppe *ppe) {
+  ngtcp2_crypto_cc *cc = ppe->cc;
+
+  return ngtcp2_buf_len(&ppe->buf) + cc->aead.max_overhead;
+}
+
+size_t ngtcp2_ppe_padding(ngtcp2_ppe *ppe) {
+  ngtcp2_crypto_cc *cc = ppe->cc;
+  ngtcp2_buf *buf = &ppe->buf;
+  size_t len;
+
+  assert(ngtcp2_buf_left(buf) >= cc->aead.max_overhead);
+
+  len = ngtcp2_buf_left(buf) - cc->aead.max_overhead;
+  memset(buf->last, 0, len);
+  buf->last += len;
+
+  return len;
+}
+
+size_t ngtcp2_ppe_padding_hp_sample(ngtcp2_ppe *ppe) {
+  ngtcp2_crypto_cc *cc = ppe->cc;
+  ngtcp2_buf *buf = &ppe->buf;
+  size_t max_samplelen;
+  size_t len = 0;
+
+  assert(cc->aead.max_overhead);
+
+  max_samplelen =
+      ngtcp2_buf_len(buf) + cc->aead.max_overhead - ppe->sample_offset;
+  if (max_samplelen < NGTCP2_HP_SAMPLELEN) {
+    len = NGTCP2_HP_SAMPLELEN - max_samplelen;
+    assert(ngtcp2_ppe_left(ppe) >= len);
+    memset(buf->last, 0, len);
+    buf->last += len;
+  }
+
+  return len;
+}
+
+size_t ngtcp2_ppe_padding_size(ngtcp2_ppe *ppe, size_t n) {
+  ngtcp2_crypto_cc *cc = ppe->cc;
+  ngtcp2_buf *buf = &ppe->buf;
+  size_t pktlen = ngtcp2_buf_len(buf) + cc->aead.max_overhead;
+  size_t len;
+
+  if (pktlen >= n) {
+    return 0;
+  }
+
+  len = n - pktlen;
+  buf->last = ngtcp2_setmem(buf->last, 0, len);
+
+  return len;
+}
+
+int ngtcp2_ppe_ensure_hp_sample(ngtcp2_ppe *ppe) {
+  ngtcp2_buf *buf = &ppe->buf;
+  return ngtcp2_buf_left(buf) >= (4 - ppe->pkt_numlen) + NGTCP2_HP_SAMPLELEN;
+}