QUIC wire format support

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18382)

1 files changed, 72 insertions, 4 deletions

diff --git a/crypto/packet.c b/crypto/packet.c
index 09f6a9cea9..5123426d75 100644
--- a/crypto/packet.c
+++ b/crypto/packet.c
@@ -225,6 +225,18 @@ static int put_value(unsigned char *data, size_t value, size_t len)
     return 1;
 }
 
+static int put_quic_value(unsigned char *data, size_t value, size_t len)
+{
+    if (data == NULL)
+        return 1;
+
+    /* Value too large for field. */
+    if (ossl_quic_vlint_encode_len(value) > len)
+        return 0;
+
+    ossl_quic_vlint_encode_n(data, value, len);
+    return 1;
+}
 
 /*
  * Internal helper function used by WPACKET_close(), WPACKET_finish() and
@@ -261,10 +273,15 @@ static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
     if (sub->lenbytes > 0) {
         unsigned char *buf = GETBUF(pkt);
 
-        if (buf != NULL
-                && !put_value(&buf[sub->packet_len], packlen,
-                              sub->lenbytes))
-            return 0;
+        if (buf != NULL) {
+            if ((sub->flags & WPACKET_FLAGS_QUIC_VLINT) == 0) {
+                if (!put_value(&buf[sub->packet_len], packlen, sub->lenbytes))
+                    return 0;
+            } else {
+                if (!put_quic_value(&buf[sub->packet_len], packlen, sub->lenbytes))
+                    return 0;
+            }
+        }
     } else if (pkt->endfirst && sub->parent != NULL
                && (packlen != 0
                    || (sub->flags
@@ -510,3 +527,54 @@ void WPACKET_cleanup(WPACKET *pkt)
     }
     pkt->subs = NULL;
 }
+
+int WPACKET_start_quic_sub_packet_bound(WPACKET *pkt, size_t max_len)
+{
+    size_t enclen = ossl_quic_vlint_encode_len(max_len);
+
+    if (enclen == 0)
+        return 0;
+
+    if (WPACKET_start_sub_packet_len__(pkt, enclen) == 0)
+        return 0;
+
+    pkt->subs->flags |= WPACKET_FLAGS_QUIC_VLINT;
+    return 1;
+}
+
+int WPACKET_start_quic_sub_packet(WPACKET *pkt)
+{
+    /*
+     * Assume no (sub)packet will exceed 4GiB, thus the 8-byte encoding need not
+     * be used.
+     */
+    return WPACKET_start_quic_sub_packet_bound(pkt, OSSL_QUIC_VLINT_4B_MIN);
+}
+
+int WPACKET_quic_sub_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
+{
+    if (!WPACKET_start_quic_sub_packet_bound(pkt, len)
+            || !WPACKET_allocate_bytes(pkt, len, allocbytes)
+            || !WPACKET_close(pkt))
+        return 0;
+
+    return 1;
+}
+
+/*
+ * Write a QUIC variable-length integer to the packet.
+ */
+int WPACKET_quic_write_vlint(WPACKET *pkt, uint64_t v)
+{
+    unsigned char *b = NULL;
+    size_t enclen = ossl_quic_vlint_encode_len(v);
+
+    if (enclen == 0)
+        return 0;
+
+    if (WPACKET_allocate_bytes(pkt, enclen, &b) == 0)
+        return 0;
+
+    ossl_quic_vlint_encode(b, v);
+    return 1;
+}