gitee.com/ks-custle/core-gm@v0.0.0-20230922171213-b83bdd97b62c/grpc/credentials/alts/internal/conn/utils.go (about)

     1  /*
     2   *
     3   * Copyright 2018 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  package conn
    20  
    21  import core "gitee.com/ks-custle/core-gm/grpc/credentials/alts/internal"
    22  
    23  // NewOutCounter returns an outgoing counter initialized to the starting sequence
    24  // number for the client/server side of a connection.
    25  func NewOutCounter(s core.Side, overflowLen int) (c Counter) {
    26  	c.overflowLen = overflowLen
    27  	if s == core.ServerSide {
    28  		// Server counters in ALTS record have the little-endian high bit
    29  		// set.
    30  		c.value[counterLen-1] = 0x80
    31  	}
    32  	return
    33  }
    34  
    35  // NewInCounter returns an incoming counter initialized to the starting sequence
    36  // number for the client/server side of a connection. This is used in ALTS record
    37  // to check that incoming counters are as expected, since ALTS record guarantees
    38  // that messages are unwrapped in the same order that the peer wrapped them.
    39  func NewInCounter(s core.Side, overflowLen int) (c Counter) {
    40  	c.overflowLen = overflowLen
    41  	if s == core.ClientSide {
    42  		// Server counters in ALTS record have the little-endian high bit
    43  		// set.
    44  		c.value[counterLen-1] = 0x80
    45  	}
    46  	return
    47  }
    48  
    49  // CounterFromValue creates a new counter given an initial value.
    50  func CounterFromValue(value []byte, overflowLen int) (c Counter) {
    51  	c.overflowLen = overflowLen
    52  	copy(c.value[:], value)
    53  	return
    54  }
    55  
    56  // CounterSide returns the connection side (client/server) a sequence counter is
    57  // associated with.
    58  func CounterSide(c []byte) core.Side {
    59  	if c[counterLen-1]&0x80 == 0x80 {
    60  		return core.ServerSide
    61  	}
    62  	return core.ClientSide
    63  }