102 lines
3.2 KiB
Objective-C
102 lines
3.2 KiB
Objective-C
//
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// PacketStream.m
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// TunnelKit
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//
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// Created by Davide De Rosa on 4/25/19.
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// Copyright (c) 2021 Davide De Rosa. All rights reserved.
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//
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// https://github.com/passepartoutvpn
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//
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// This file is part of TunnelKit.
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//
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// TunnelKit is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// TunnelKit is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with TunnelKit. If not, see <http://www.gnu.org/licenses/>.
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//
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#import "PacketStream.h"
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static const NSInteger PacketStreamHeaderLength = sizeof(uint16_t);
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@implementation PacketStream
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+ (void)memcpyXor:(uint8_t *)dst src:(NSData *)src xorMask:(uint8_t)xorMask
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{
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if (xorMask != 0) {
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for (int i = 0; i < src.length; ++i) {
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dst[i] = ((uint8_t *)(src.bytes))[i] ^ xorMask;
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}
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return;
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}
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memcpy(dst, src.bytes, src.length);
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}
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+ (NSArray<NSData *> *)packetsFromStream:(NSData *)stream until:(NSInteger *)until xorMask:(uint8_t)xorMask
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{
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NSInteger ni = 0;
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NSMutableArray<NSData *> *parsed = [[NSMutableArray alloc] init];
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while (ni + PacketStreamHeaderLength <= stream.length) {
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const NSInteger packlen = CFSwapInt16BigToHost(*(uint16_t *)(stream.bytes + ni));
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const NSInteger start = ni + PacketStreamHeaderLength;
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const NSInteger end = start + packlen;
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if (end > stream.length) {
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break;
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}
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NSData *packet = [stream subdataWithRange:NSMakeRange(start, packlen)];
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uint8_t* packetBytes = (uint8_t*) packet.bytes;
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if (xorMask != 0) {
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for (int i = 0; i < packet.length; i++) {
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packetBytes[i] ^= xorMask;
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}
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}
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[parsed addObject:packet];
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ni = end;
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}
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if (until) {
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*until = ni;
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}
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return parsed;
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}
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+ (NSData *)streamFromPacket:(NSData *)packet xorMask:(uint8_t)xorMask
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{
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NSMutableData *raw = [[NSMutableData alloc] initWithLength:(PacketStreamHeaderLength + packet.length)];
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uint8_t *ptr = raw.mutableBytes;
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*(uint16_t *)ptr = CFSwapInt16HostToBig(packet.length);
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ptr += PacketStreamHeaderLength;
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[PacketStream memcpyXor:ptr src:packet xorMask:xorMask];
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return raw;
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}
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+ (NSData *)streamFromPackets:(NSArray<NSData *> *)packets xorMask:(uint8_t)xorMask
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{
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NSInteger streamLength = 0;
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for (NSData *p in packets) {
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streamLength += PacketStreamHeaderLength + p.length;
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}
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NSMutableData *raw = [[NSMutableData alloc] initWithLength:streamLength];
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uint8_t *ptr = raw.mutableBytes;
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for (NSData *packet in packets) {
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*(uint16_t *)ptr = CFSwapInt16HostToBig(packet.length);
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ptr += PacketStreamHeaderLength;
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[PacketStream memcpyXor:ptr src:packet xorMask:xorMask];
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ptr += packet.length;
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}
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return raw;
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}
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@end
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